JP2006525460A - Fluid pump - Google Patents

Abstract

The present invention provides a fluid pump that includes a housing defining a cavity. The cavity includes at least one fluid inlet and outlet and at least one set of coils for generating a magnetic field. In use, the impeller (3) comprises the body, the cavity comprising a number of vanes (4A, 4B) and a number of driver magnets (9) located on the body for biasing fluid from the inlet to the outlet Located in. In use, the impeller is suspended in the cavity by axial coupling and is rotated by the magnetic field generated by the coil.

Description

  The present invention relates to motors, and more particularly to a fluid pump using an impeller suitable for use as a cardiac assist device or heart replacement device, such as an LVAD (left ventricular device) or BiVAD (biventricular device).

  In this specification, reference to any prior art does not mean that the prior art forms part of ordinary general knowledge, or any form of suggestion, It should not be considered that way.

  High-quality, high-productivity machines require high-speed, maintenance-free motors. Since such motors use non-contact supports, magnetic bearings have been gradually introduced into these machines. However, early magnetic bearing systems required a separate drive motor. Therefore, when this technique is applied to a fluid pump, a seal is required to prevent fluid from contacting the drive motor.

  In order to overcome this problem, self-bearing motors have been developed. Self-bearing motors generate a magnetic field that operates to suspend and rotate the rotor, thereby removing bearing and motor functions from the same set of coils or two sets of coils located at the same circumferential position. Can be provided. A number of magnetic principles can achieve this goal based on the so-called reluctance and Lorentz theory. When applied to centrifugal pump technology, the use of a self-bearing motor eliminates the need to use a shaft or seal. This is because the rotor is completely contained within the pump cavity.

This is particularly relevant in the field of cardiac transplant surgery that has been developed as a high performance response to the problem of life-threatening damage to the human heart.
However, as the average age of the entire population increases, the absolute number of severe heart failure is increasing, and the number of patients who will eventually undergo heart transplant surgery is increasing. Unfortunately, there is always a shortage of suitable substitute organs available, making it increasingly difficult to use for all patients at risk of serious death due to the heart Yes.

  Another approach to the lack of available cardiac donors is to increase the work of the patient's heart, or ideally, an artificial pump that is suitable for replacing the entire malfunctioning heart Various attempts have been made to develop

  One of the challenges in providing such an effective pump is that the available power source must be used efficiently. Since it is very important to operate with high reliability without stopping such a pump, it is necessary to peak efficiency when using the power supply. When functioning for purposes other than experimental prototypes, such pumps must allow the patient to remain without a device for refueling or refilling for a significant amount of time.

  The pump must also minimize the destructive effects of the pump mechanism on the blood cells. All pump segments that generate excessive shear stress cause traumatic hemolysis in that region. In addition, segments that promote blood retention can form dangerous clots in the pump that travel throughout the body, are carried, and are necessary for life support in the surrounding circulatory system. Potentially occludes the artery.

  One of the important problems of energy loss and blood trauma occurs in connection with the method of rotating the pump rotor, i.e. the impeller. The use of conventional bearings to support the rotor can cause increased power consumption and device lifetime problems associated with frictional resistance and consequent wear, respectively. In addition, this technique promotes blood cell trauma due to excessive heat generation and high shear stress at the bearing contact sites associated with flow dwelling around the rotating shaft. This means that maintenance procedures must be performed to remove these adverse effects.

Various attempts have been made to suspend the pump rotor or impeller magnetically or hydrodynamically in order to provide a bearing that is friction free and does not require a seal.
Patent document 1 entitled “Rotary Pump With Hydrodynamically Suspended Impeller” (Rotary Pump with Dynamically Suspended Impeller) has an open or closed impeller blade whose edge is used as a fluid thrust bearing. A pump without the featured seal and shaft is described. The rotational torque is supplied by the interaction between a magnet embedded in the blade and a rotating magnetic field generated in a coil fixed to the pump housing.

  In the case of a fluid bearing, the gap needs to be relatively narrow in order to supply a sufficient bearing force. High shear stress is located in such a gap, and if blood cells enter this region, hemolysis may occur. Hydrodynamic bearings rely on a passive response to the force applied to the impeller. That is, the bearing stiffness cannot be changed for a given condition. If the force exceeds the predetermined bearing stiffness, touchdown will occur soon. Furthermore, a hydrodynamically suspended rotor generates bearing force stiffness in proportion to the rotational speed of the rotor. Ventricular assist devices can destroy the ventricular wall if the circulatory system requires excessive flow and can therefore occlude the inlet cannula to the pump. In order to prevent this annoying problem, the rotational speed of the pump must be reduced for some time so that the ventricular wall can be separated from the situation where the pump with suspended fluid bearings cannot do anything. This is because reducing the rotational speed reduces bearing stiffness and reduces potential impeller touchdown.

  From the standpoint of potential obstacles to passive hydrodynamic suspension technology, for example, as described in Patent Document 2 and Patent Document 3, the magnetic bearing technology that controls the position of the rotor in the pump cavity is mainly used. Other configurations have been proposed.

  Patent Document 2 entitled “Magnetically Suspended and Rotated Rotor” includes a permanent magnet located in an impeller and a pump housing, respectively, and stabilized by an electromagnet on the housing. An impeller for a supported blood pump is described. This configuration of the magnetic suspension system is inefficient due to the relatively wide magnetic “air gap”. That is, the distance from the rotor magnet to the housing magnet is relatively long, so that excessive magnetic flux leakage occurs and efficiency is lowered. Furthermore, to provide both functions separately, the magnetic suspension system is remote from the drive mechanism, increasing size and electronic circuitry.

U.S. Pat. No. 6,057,056 describes an improved rotor for a blood pump that relies on the position of the impeller to achieve the dynamic balance achieved by a combination of fluid and buoyancy. The rotor is electromagnetically driven by an electromagnetic drive system that operates with one or more arrays of permanent magnets. Permanent magnets can be housed in radial vanes on the surface of the rotor including drive components arranged in a brushless motor configuration. In this device, the rotational movement of the rotor takes place around an axis that changes relative to the pump housing.
US Pat. No. 6,609,883 US Pat. No. 5,326,344 International Publication No. 99/01663 Pamphlet

  This arrangement is due to an attempt to eliminate the need for very precise axis control and design and manufacture. Part of the immediate problem is that in a magnetic levitation system, if the rotor axis deviates from its normally centered position, it must avoid introducing large forces that would otherwise occur. It is. The rotor includes a series of external shrouds that are formed around an internal hole for containing the inlet fluid and provide a plurality of annular flow channels. This arrangement increases the surface area in contact with blood during normal pump operation. Red blood cell fragility has become a very important concern in such devices. This is because the shear and frictional interaction between the moving component and the blood volume tends to lyse the red blood cells.

  In addition, most centrifugal heart pumps that have been used to assist the left ventricle to date are characterized by a conventional one-sided suction impeller. That is, a rotating impeller that includes a set of vanes is used to bias blood from one inlet to one outlet. However, this technology can generate unbalanced fluid forces experienced by the impeller that must be countered by the dwell zone under the impeller and the forces generated by the suspension technology, thus increasing the bearing power requirements. , Increasing the overall loss of efficiency. Attempting to put magnetic material in the rotor required for suspension and / or drive will not work because the rotor size is very small. By using a double-sided suction impeller, the axial fluid force is better balanced and there is no potential stagnation zone.

  In addition, when using these pumps to solve the use of biventricular assist, the current technology must implant and operate two separate pumps, and two for assisting the left and right heart Since independent pumps must be controlled, the transplant size is increased and control is further complicated. Attempts to generate one rotary centrifuge device, BiVAD, are difficult to vary the output flow of each cavity separately because the impellers have a common rotational speed, and from the high pressure left cavity Difficult to prevent leakage into low pressure right cavity.

In the case of the first broad form, the present invention provides:
a) a housing forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a housing having a set of coils for generating a magnetic field;
b) an impeller located in the cavity,
i) in use, a body forming an impeller axis substantially parallel to the cavity axis;
ii) a number of vanes located on the body for urging fluid from the inlet to the outlet during use;
iii) an impeller having a number of driver magnets located in the magnetic field during use;
c) at least two sensors capable of detecting the position of the impeller in the cavity;
d) a radial bearing for controlling the position of the impeller in a direction perpendicular to the cavity axis;
e) an axial coupling to control the position of the impeller in a direction parallel to the cavity axis;
f) A fluid pump including a sensor and a controller coupled to the first and second sets of coils to control the magnetic field during use and thereby control the rotation of the impeller about the impeller axis. I will provide a.

Axial coupling is
a) a second set of coils for generating a second magnetic field;
b) can be included in the body and include a number of axial support magnets located in use in the second magnetic field. In that case, the control device controls the second magnetic field, thereby controlling the movement of the impeller in a direction parallel to the cavity axis.

  The axial coupling may include a first set of coils and a number of axial support magnets provided in the body and located in the magnetic field during use. In that case, the control device controls the magnetic field, thereby controlling the movement of the impeller in a direction parallel to the cavity axis.

Axial coupling is
a) a set of magnets coupled to the housing to generate an axial control magnetic field, and b) provided within the body and located within the axial control magnetic field during use thereby It may include at least one of a number of axial support magnets that limit impeller motion in a direction parallel to the cavity axis.

The support magnet in the axial direction may be a driver magnet.
Axial coupling is
a) a first bearing member coupled to the housing;
b) may include a second bearing member coupled to the impeller. The first and second bearing members cooperate to limit impeller movement in a direction parallel to the cavity axis.

Radial bearings
a) the inner surface of the housing;
b) When the fluid is pumped in use, a boundary layer is formed between the inner surface portion and the outer surface portion, thereby cooperating with the inner surface so that impeller movement in a direction perpendicular to the cavity axis is limited. And at least a portion of the outer surface of the impeller shaped like this.

  The radial bearing can include a second set of coils for generating a second magnetic field. In this case, the control device controls the third magnetic field by the signal from the sensor, thereby controlling the movement of the impeller in the direction perpendicular to the cavity axis.

The fluid pump typically includes at least one sensor located at the first end of the cavity and at least two sensors located at the second opposite end of the cavity.
The vane dimensions are usually selected to control at least one of the fluid pressure and flow rate at the outlet.

This dimension is
a) The height of the blade,
b) impeller diameter,
c) the length of the blade,
d) blade width,
e) the angle of the inlet and outlet vanes,
f) blade shape,
g) may include at least one of the number of vanes.

Normal,
a) The housing is
i) at least two fluid inlets;
ii) including at least two fluid outlets;
b) The impeller
i) at least two body portions;
ii) including first and second sets of vanes located on the first and second body portions, respectively. Each pair of vanes is for urging fluid from each inlet to each outlet during use.

  Preferably, the impeller cooperates with the cavity to form first and second cavity portions. Each cavity portion includes an inlet, an outlet, and an impeller, respectively, and the cavities are configured to substantially prevent movement of fluid between the cavity portions.

The first and second sets of vanes each have approximately the same dimensions, thereby providing fluid at the outlet at approximately the same pressure and flow rate.
The first and second sets of vanes have different respective dimensions, thereby supplying fluid at respective first and second pressures at each outlet.

The first outlet can be coupled to the second inlet.
The cavity can be substantially rotationally symmetric with respect to the cavity axis, in which case the coils are circumferentially spaced around the cavity.

The main body is substantially rotationally symmetric with respect to the impeller shaft, and the driver magnets are directed radially outward from the impeller shaft and are spaced circumferentially about the impeller shaft.
Preferably, the driver magnet is preferably located inward in the radial direction of the coil.

The first set of coils can be located radially inward of the second set of coils.
The coil is usually mounted on the yoke.

The yoke can include a slot for receiving a coil.
A set of coils can include three pairs of first coils. The first coil in each pair is located opposite the circumferential direction so that the controller can conduct current through the coil in the corresponding direction, thereby rotating the impeller.

The control device
a) Determine the required impeller rotation speed,
b) determining a control signal sequence for each pair of first coils;
c) Each control signal sequence can be supplied to each pair of first coils to move the driver in a predetermined direction and thereby rotate the impeller.

  The second set of coils can include three pairs of second coils. The second coil in each pair is located oppositely in the circumferential direction so that the controller can pass current through the coil in the corresponding opposite direction, thereby driving the driver member relative to the cavity axis. It can move in the radial direction.

The control device is usually
a) monitor the sensor;
b) determining the movement of the driver shaft in the radial direction relative to the cavity axis;
c) selecting one or more pairs of second magnets;
d) generate a control signal for each selected pair;
e) A control signal can be supplied to each selected pair to move the driver in a predetermined direction, thereby moving the driver axis in the direction of the cavity axis.

  The controller can be formed from a processing system having a memory and a processor. The processing system can generate a control signal for controlling the magnetic field generated by the coil according to a predetermined algorithm stored in the memory.

The processing system can be combined with a signal generator. The control signal can be generated by causing the signal generator to pass a predetermined current through the coil by the processing system.
The driver magnet can include eight circumferentially spaced permanent magnets. The magnetic poles of the magnets are aligned in a direction perpendicular to the driver shaft, and are arranged so that the alignment direction of the magnetic poles is reversed between adjacent magnets.

The body is
a) two body ends,
b) can include a number of vanes located on the ends of the body. The blades extend from the surface of the end of the body in a direction substantially parallel to the driver shaft, are radially outward from the driver shaft, and are spaced circumferentially around the driver shaft.

Each body end is generally conical.
The body can include a generally cylindrical central body portion located between the two body ends. The driver magnet is located within the cylindrical central body portion.

The cavity can include first and second cavity ends. Each cavity end is
a) an inlet located along the cavity axis;
b) facing the direction perpendicular to the cavity axis and having an outlet arranged radially offset from the cavity axis;
c) It is generally conical to cooperate with the impeller so that the vanes can bias fluid from the inlet to the outlet against rotation of the impeller.

  The impeller and cavity usually work together to substantially prevent fluid from flowing from one cavity end to the other cavity end. The vanes on each body end have a respective height or length, thereby controlling the fluid pressure or flow rate at the outlet in each end.

Preferably, the pump includes at least two sensors located within at least one of the cavity ends, thereby measuring the distance between the sensors and the surface of each body end.
The impeller can include a shroud that is coupled to the vanes. The sensor can determine the position of the shroud.

The pump may include at least three sensors located radially outward from the cavity axis and spaced circumferentially around the cavity axis.
The sensor can include a radiation source capable of emitting radiation in the direction of the surface of each body end, and a detector for detecting the reflected radiation.

The impeller can include a position magnet, and the sensor is formed from a Hall effect sensor that can determine the magnetic field generated by the position magnet.
In this case, the position magnet may be a driver magnet.

The support magnet can take the form of a substantially cone or a truncated cone.
The impeller and the cavity can take a substantially cylindrical shape.
The impeller can include one or more wedges located on the outer periphery of the body, thereby cooperating with the inner surface to hydrodynamically control the position of the impeller in a direction perpendicular to the cavity axis.

A wedge can be provided in the central body portion.
The axial support magnet can be formed from a magnet material located in the magnetic field.
The axial support magnet can be made from soft iron.

The impeller can include a shroud on each body end.
Each shroud can include a driver magnet.
Each shroud can include an axial support magnet.

The pump can include a set of second magnets located within each of the two cavity ends.
In the case of the first broad form, the present invention provides:
a) a housing forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a housing having first and second sets of coils for generating first and second magnetic fields;
b) an impeller located in the cavity,
i) in use, a body forming an impeller axis substantially parallel to the cavity axis;
ii) a number of vanes located on the body to urge fluid from the inlet to the outlet during use;
iii) an impeller having a number of driver magnets located within the first and second magnetic fields during use;
c) at least two sensors capable of detecting the position of the impeller in the cavity;
d) combined with the first and second sets of sensors and coils and in use;
i) controlling the first magnetic field, thereby controlling the rotation of the impeller about the impeller axis;
ii) providing a fluid pump comprising a controller for controlling the second magnetic field and thereby controlling the movement of the impeller in a direction perpendicular to the cavity axis.

The control device can control the second magnetic field, thereby controlling the movement of the impeller parallel to the cavity axis.
The fluid pump can include an axial coupling to limit impeller motion in a direction parallel to the cavity axis.

In the case of the first broad form, the present invention provides:
a) a housing having an inner surface forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a housing having a set of coils coupled to the housing to generate a magnetic field;
b) an impeller located in the cavity,
i) a body forming an impeller shaft;
ii) a number of vanes located on the body to urge fluid from the inlet to the outlet during use;
iii) a number of driver magnets located in the magnetic field during use;
iv) When the fluid is pumped on the outer surface and in use, a boundary layer is formed between the inner surface portion and the outer surface portion, thereby limiting impeller movement in a direction perpendicular to the cavity axis, An impeller having an outer surface shaped such that at least a portion of the outer surface cooperates with a correspondingly shaped portion of the inner surface;
c) axial coupling to limit impeller movement in a direction parallel to the cavity axis;
d) providing a fluid pump including a controller for controlling the first magnetic field and thereby rotating the impeller about the impeller axis;

Axial coupling is
a) a second set of coils for generating a second magnetic field;
b) at least two sensors for sensing the position of the impeller in the cavity, wherein the controller is coupled to the second set of sensors and coils, and in use, the controller has a second magnetic field Thereby controlling the movement of the impeller in a direction parallel to the cavity axis.

Axial coupling is
a) a set of magnets coupled to the housing to generate an axial control magnetic field, and b) provided within the body and located within the axial control magnetic field during use thereby It may include at least one of a number of axial support magnets that limit impeller motion in a direction parallel to the cavity axis.

Axial coupling is
a) a first bearing member coupled to the housing;
b) a second bearing member coupled to the impeller. The first and second bearing members cooperate to limit impeller movement in a direction parallel to the cavity axis.

In the case of the first broad form, the present invention provides:
a) a housing forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a housing having a set of coils for generating a magnetic field;
b) an impeller located in the cavity,
i) in use, a body forming an impeller axis substantially parallel to the cavity axis;
ii) a number of vanes located on the body to urge fluid from the inlet to the outlet during use;
iii) during use, an impeller having a number of driver magnets located in the first magnetic field;
c) at least two sensors capable of detecting the position of the impeller in the cavity;
d) a controller coupled to a sensor and a set of coils, which in use controls the magnetic field, thereby i) controlling the rotation of the impeller about the impeller axis;
and ii) a fluid pump including a controller that controls the movement of the impeller in a direction parallel to the cavity axis.

In the case of the first broad form, the present invention provides:
a) a housing forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a set of coils for generating a first magnetic field;
iv) a housing having a set of magnets for generating an axial control magnetic field;
b) an impeller located in the cavity,
i) in use, a body forming an impeller axis substantially parallel to the cavity axis;
ii) a number of vanes located on the body to urge fluid from the inlet to the outlet during use;
iii) a number of driver magnets located in the first magnetic field during use;
iv) an impeller having a number of support magnets located in the axial control field and thereby restricting the movement of the impeller in a direction parallel to the cavity axis;
c) providing a fluid pump including a controller coupled to a set of coils to control the first magnetic field, thereby controlling the rotation of the driver about the driver axis.

In the case of the first broad form, the present invention provides:
a) a housing forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a first bearing member;
iv) a housing having a set of coils for generating each magnetic field;
b) an impeller located in the cavity,
i) in use, a body forming an impeller axis substantially parallel to the cavity axis;
ii) a number of vanes located on the body to urge fluid from the inlet to the outlet during use;
iii) multiple driver magnets;
iv) an impeller having a second bearing member, wherein the first and second bearing members cooperate to thereby limit impeller movement in a direction parallel to the cavity axis;
c) providing a fluid pump including a controller coupled to a set of coils and capable of controlling the magnetic field generated by the first set of coils and thereby controlling the rotation of the driver about the driver axis. To do.

The fluid pump typically further includes a radial bearing for controlling the movement of the impeller in a direction perpendicular to the cavity axis.
Radial bearings
a) the inner surface of the housing;
b) having an outer surface, and in use, when the fluid is pumped, a boundary layer is formed between the inner surface portion and the outer surface portion, thereby limiting impeller movement in a direction perpendicular to the cavity axis. And an impeller having at least a portion of the outer surface shaped to cooperate with a correspondingly shaped portion of the inner surface.

Radial bearings
a) a second set of coils for generating a second magnetic field;
b) may include at least two sensors capable of detecting the position of the impeller within the cavity. In this case, the control device controls the third magnetic field by the signal from the sensor, thereby controlling the movement of the impeller in the direction perpendicular to the cavity axis.

The fluid pump includes at least one sensor located at the first end of the cavity and at least two sensors located at the second opposite end of the cavity.
In the case of the first broad form, the present invention provides:
a) a housing having an inner surface forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a set of coils coupled to the housing for generating the first magnetic field;
iv) a housing having a set of magnets coupled to the housing to generate an axial control magnetic field;
b) an impeller located in the cavity for biasing fluid from the inlet to the outlet,
i) a body forming an impeller shaft;
ii) in use, a number of driver magnets located in the first magnetic field;
iii) On the outer surface, when the fluid is pumped in use, a boundary layer is formed between the inner surface portion and the outer surface portion so that impeller motion in a direction perpendicular to the cavity axis is limited. An outer surface shaped such that at least a portion of the outer surface cooperates with a correspondingly shaped portion of the inner surface;
iv) an impeller having a number of axial support magnets located in the axial control field and thereby restricting the movement of the impeller in a direction parallel to the cavity axis;
c) providing a fluid pump including a control device for controlling the magnetic field and thereby rotating the impeller about the impeller axis.

In the first broad form, the present invention is a method for pumping fluid by a fluid pump, wherein the fluid pump comprises:
a) a housing forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a housing having first and second sets of coils for generating first and second magnetic fields;
b) an impeller located in the cavity,
i) a body forming an impeller axis substantially parallel to the cavity axis;
ii) a number of vanes located on the body to urge fluid from the inlet to the outlet during use;
iii) an impeller having a number of driver magnets located within the first and second magnetic fields during use;
c) having at least two sensors capable of detecting the position of the impeller in the cavity;
i) controlling the first magnetic field, thereby controlling the rotation of the impeller about the impeller axis;
ii) controlling the second magnetic field, thereby controlling the movement of the impeller in a direction perpendicular to the cavity axis.

In the first broad form, the present invention is a method for pumping fluid by a fluid pump, wherein the fluid pump comprises:
a) a housing forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a housing having a set of coils for generating a magnetic field;
b) an impeller located in the cavity,
i) in use, a body forming an impeller axis substantially parallel to the cavity axis;
ii) a number of vanes located on the body to urge fluid from the inlet to the outlet during use;
iii) an impeller having a number of driver magnets located in the magnetic field during use;
c) having at least two sensors capable of detecting the position of the impeller in the cavity and controlling the magnetic field, and i) controlling the rotation of the impeller about the impeller axis;
ii) controlling the movement of the impeller in a direction parallel to the cavity axis.

  In the case of the first broad form, the present invention, when executed on a suitable processing system, causes the processing system to perform the method seen from the eighth and ninth broad forms of claim 46 or 48. A computer program product including computer executable code is provided.

In the case of the first broad configuration, the present invention is mounted in a pump cavity for use with a fluid pump, and the fluid flows from the first and second inlets to the corresponding first and second outlets. To provide an impeller that can be biased. Impeller
a) a main body forming an impeller shaft and including first and second main body ends;
b) in use, a set of vanes located on each body end to bias fluid from each inlet to the corresponding outlet;
c) a number of driver magnets located within the first and second magnetic fields during use;
d) In use, when the fluid is pumped, a boundary layer is formed between the inner surface portion and the outer surface portion, thereby limiting the movement of the impeller in a direction perpendicular to the cavity axis. And an outer surface portion shaped to cooperate with a portion of the shape.

The impeller forms part of a fluid pump according to claim 4.
In the case of the first broad configuration, the present invention is mounted in a pump cavity for use with a fluid pump, and the fluid flows from the first and second inlets to the corresponding first and second outlets. To provide an impeller that can be biased. Impeller
a) a main body forming an impeller shaft and including first and second main body ends;
b) a pair of vanes located on each body end to bias fluid from each inlet to the corresponding outlet during use;
c) a number of driver magnets located within the first and second magnetic fields during use;
d) including at least a first portion of an axial coupling for limiting impeller movement in a direction parallel to the impeller axis.

Axial coupling is
a) a second bearing member capable of cooperating with a first bearing member provided on the housing, and b) of a number of support magnets for positioning an axial control magnetic field during use At least one of them can be included.

The vane dimensions are usually selected to control at least one of the fluid pressure and flow rate at the outlet.
This dimension is usually
a) The height of the blade,
b) impeller diameter,
c) the length of the blade,
d) blade width,
e) the angle of the inlet and outlet vanes,
f) blade shape,
g) including at least one of the number of blades.

  The impeller is in use during pump use so that the inlets are aligned parallel to the body axis when each inlet is positioned to deliver fluid along the body axis in the direction of each body end. It can be located in the cavity. The impeller rotates during use, thereby urging the fluid radially outward in the direction of the outlet.

The body can include a generally cylindrical central body portion located between the two ends. The driver magnet is located within the cylindrical central body portion.
The impeller can cooperate with the pump cavity to form first and second cavity portions. Each cavity portion includes a respective inlet, outlet, and body end. The impeller can substantially prevent fluid movement between the cavities.

The impeller can be used with a heart pump. The first and second sets of wings can each pump blood to assist the left and right ventricles.

An example of the present invention will be described with reference to the accompanying drawings.
1A to 1E are examples of a fluid pump incorporating a double impeller. As shown, the pump includes a housing 1 having two conical ends 1A, 1B forming a cavity 2 containing an impeller 3 therein. The impeller is formed from two generally conical body ends 3A, 3B each having a number of vanes 4 mounted thereon.

Each housing part 1A, 1B comprises an inlet 5A, 5B and an outlet 6A, 6B.
The housing includes a gap gap 8A between the rim 8 and the impeller 3 that effectively cooperate to divide the cavity 2 into two cavities. The cavity ends form 2A and 2B, respectively, to reduce fluid flow between the two cavities. Therefore, in this example, the pump efficiently incorporates two pumps formed by the cavities 2A, 2B. During use, the impeller 3 rotates about an axis indicated generally by the reference numeral 7. As will be appreciated by those skilled in the art, this rotation forces the fluid at each inlet 5A, 5B in the direction of each outlet 6A, 6B.

  In order to improve the operating efficiency, it is preferred that the inlets 5A, 5B are aligned with the cavity shaft 7, thereby directing the flow of blood directly onto the impeller 3, thereby contacting the vanes 4. Thereby, the influence of the radial displacement on the impeller 3 due to the flow of fluid into the pump is reduced to a minimum. However, in order to reduce the size of the axial device and improve anatomical compatibility when using a heart pump, fluid must enter the cavity from a direction substantially perpendicular to the cavity axis. To accomplish this, the inlet includes a 90 degree bend to align the fluid inflow into the cavity 2 along the cavity axis 7.

  Note that although this arrangement is anatomically suitable, a straight cannula parallel to the axis of rotation 7 of the impeller can be used instead of the inlet volutes 5A, 5B.

  This can be achieved by the inlet volute 5C, 5D. An example is shown in FIGS. 2A and 2B. The flow enters the inlet volute 5C, 5C through each port 5E, 5F and comprises a lip 5H at the eye of the rotating component and impeller in the form of a volute shown at 5G. This lip 5H also reduces circulation and potential stagnation within this region. Therefore, it has a spiral component that assists in moving into the rotating impeller blades as fluid enters the inlets 5A, 5B. Inlet volutes 5C, 5D further improve anatomical compatibility when a fluid pump is implanted under the patient's heart. In the case of some examples of pumps, it is preferred that the inlet and outlet flows be in the same plane. Furthermore, the axial size of the fluid can be reduced by using a flat “pancake” type inlet volute.

  In use, the inlet volutes 5C, 5D direct the blood in the direction of the rotating impeller 3. The vane 4 is in the form of a helical channel and moves blood through each outlet volute 37A, 37B connected to the outlet 6A, 6B, respectively.

  2C-2F show examples of multiple exit volutes. As shown in FIG. 2C, the first part of the volutes 37 </ b> A and 37 </ b> B is a narrow space between the blade 4 and the inner surface of the cavity 2, called “draining” 38 </ b> A. The volute can be thicker and bulge outwardly to be continuous with the outlets 6A, 6B, or alternatively, further bulge outwardly within the vaneless diffuser 38C, as shown in FIG. 2E. This volute structure helps to reduce turbulence and reduce wall friction during inflow when the volume of blood is biased toward the outlet. This is because the fluid velocity is kept constant, thereby reducing the occurrence of shear stress and preserving the component force of the pumping fluid.

  In the embodiment of FIG. 2D, the volute is split. In this example, the radial gap gap between the rotor and the housing, or the first volute area 37A, widens from the first point (draining) 38A until it accommodates half of the impeller, ie about 180 degrees. It has become. A second drainer 38B is implemented at 180 degrees where the second volute 37B begins. A split or “double” volute has low radial thrust and has various levels of heart disease, thus improving efficiency over a wider range of motion encountered by patients in need of assistance during support.

  Alternatively, FIG. 2F shows a concentric volute. The radial hydraulic thrust is reduced only at the point where the efficiency of the single volute is highest, while the concentric volute receives the maximum radial thrust at all operating conditions.

  The levitation and rotation of the impeller 3 in the cavity 2 and around the cavity axis can be done in many ways. In one example, this levitation and rotation is installed in a coil 11, 12 with current flowing in the housing and in the impeller shown in FIG. 4B and described in further detail below. This is done by two sets of magnets consisting of a set of permanent driver magnets 9.

  In this example, the first set of magnets (coil 11) cooperates with the driver magnet 9 embedded in the impeller to supply rotational torque. The second set of magnets (coils 12) is used to form a magnet bearing that can be used to maintain the position of the impeller 3 within the cavity.

  However, if an appropriate control strategy is used, a single set of coils must provide both the bearing and motor flux generation functions. Therefore, the first and second sets of magnets (coils) can be combined into a set of magnets (coils) and a superimposed current can be applied to separately generate bearing and motor flux.

  Thus, using two sets of coils 11, 12, such that if one set of one or more coils fails, the corresponding coil in the other set of coils can perform the function. It should be understood that redundancy can be obtained.

  In use, if the impeller is located in the middle of the cavity 2, it can be positioned with minimal force. However, the position of the rotor is inherently unstable due to the negative rigidity or the attractive force of the permanent magnet on the stator. Active magnetic bearings therefore provide additional magnetic flux to counteract any disturbance forces. Schweitzer, G.M. Breuler, H .; Traxler, A .; (1994) "Active Magnetic Bearings: Basics, Characteristics and Applications of Active Magnetic Bearings" (Active Magnetic Bearings: Basics, Properties and Applications of Active Magnetic Bearings). Usually used in magnetic motor bearing system by reluctance theory.

This form of pump assembly can also assist or substitute for one or more ventricles of the mammalian heart. This connects the pump inlets 5A, 5B to the left ventricle or atrium, supplies energy to the fluid through the bilateral centrifugal impeller 3, and connects the outlets 6A, 6B to the aorta, thereby the natural function of the left heart. It is done by assisting. Additionally or alternatively, the inlets 5A, 5B can be connected to the right ventricle / atrium, and the outlets 6A, 6B can be connected to the pulmonary artery, thereby assisting the left or right or right heart, respectively.
First Specific Example A first specific example of a pump is described below with reference to a pump that can assist or substitute for the function of the left ventricle (LVAD) of the heart.

  FIG. 1A is a detailed cross-sectional view of an example of a pump used as an embodiment of a left ventricular assist device. As already explained, this configuration provides two fluid feeds to a double-sided centrifugal pump consisting of two generally conical body portions 3A, 3B each having a number of vanes 4A, 4B mounted thereon. Includes volute type inlets 5C, 5D.

  The vanes are configured such that the same pressure is generated at the outlets 6A, 6B of each cavity 2A, 2B. This actually represents two centrifugal pumps operating in parallel, so that the output flow in the cannula 40 is 2 of the flow rate generated at each outlet 6A, 6B for a specific pressure increase. Is double. In this example, the cavity 2 is divided into two cavities 2A, 2B by a narrow gap gap 8A, which is a place for a radial type magnetic motor bearing. In this example, as shown in the figure, the coils 11, 12 are resident on the outside of the pump housing 1 and are coupled to a permanent driver magnet 9 embedded in the cylindrical circumference of the impeller. is doing. This magnetic bearing provides impeller suspension and rotational torque without contact in the radial (x, y) direction. FIG. 1E is a detailed exploded view of the pump.

  The inlet flow is supplied by a single cannula 39 from the left ventricle or atrium, and two conduits connected to the inlets 5A, 5B to provide a uniform flow within both cavities 2A, 2B. It is divided into 39A and 38B. With this arrangement, left ventricular pressure fluctuations that occur during systole and diastole are routed directly through the balanced inlet volutes 5C, 5D to both inlets 5A, 5B of the pump, so that the impeller The axial thrust received by 3 is reduced to the minimum. This is a function that is difficult to obtain with a conventional one-sided pump.

  FIG. 3A is an example of the configuration of the impeller 3 used in this example. More specifically, FIG. 3A shows that the impeller consists of three parts, namely, in one example, the end parts 3A, 3B including the permanent driver magnet 9 and the central part 3C. The end portions 3A and 3B include respective sets of blades 4A and 5B as shown in the drawing.

  The configuration of the blades 4A and 4B can control the characteristics of the flow supplied to the outlets 6A and 6B. This control is performed by a number of factors, as will be described in more detail below. However, it will be appreciated that many different blade arrangements can be used.

  For example, FIG. 3B shows another impeller configuration. In this example, the shroud 3D is used on the vanes 4A, 4B to improve hydraulic efficiency and provide a closer proximity sensor target. However, this situation does not potentially increase the shear value between the shroud 3D and the cavity 2 and improves the resolution of the sensor, as will be described in more detail below.

  FIG. 3C shows an embodiment of a “sloped toward the back” vane that can be used to produce the desired flow characteristics. The outer and inner blade diameters are 4D, 4C, the exit vane angle is 4E, the entrance vane angle is 4F, and the vane height is 4G. Alternatively, as shown in FIG. 3D, it can be straightened radially from the initial portion of the blade 4 or can be tilted forward (not shown).

  Preferably, the fluid leaving the impeller 3 is collected by nine split volute type casings 37A, 37B and sent to the outlets 6A, 6B at a helical angle corresponding to the relative angle of the flow away from the vanes 4 at design conditions. It is preferable. The outlet flow is combined by conduits 40A, 40B to supply a single cannula to the aorta.

  Alternatively, each output stream 6A, 6B can be directed to a different site of the aorta, for example, the ascending and descending aorta. By doing so, additional blood flow can be supplied to certain organs that are otherwise lacking blood from one ascending aorta interface, but no additional interface sites to the circulatory system are required.

  When designing the configuration of the impeller 3 and the housing 1, those skilled in the art can understand by computational fluid dynamics technology, but it is possible to make sure that there is no residence zone in the split cannula and that a thrombus can occur. Sex must be removed.

  In an example, as shown in FIG. 4A, the impeller 3 is suspended and coupled to a driver magnet 9 installed in the central portion 3C of the impeller 3 to generate coils 11, 12 that generate respective magnetic fields. Driven by the first and second sets of

  As shown in FIG. 4B, the first and second sets of coils 11, 12 are located in the outer section of the housing 1 that circumferentially surrounds the driver magnets 9, thereby providing the necessary magnetism. Supply bearings and rotational torque.

  The set of coils 11 and 12 is disposed on a common yoke 15 that functions as a stator. Preferably, the yoke is made from a laser or water jet cut laminated or sintered iron core to reduce eddy current losses. The magnetic material may be a rare earth, neodymium, or any material that can be used to provide sufficient magnetic flux. In one example, each set consists of six coils, but the number of coils need not be six.

  As shown in FIGS. 4C to 4E, the coils 11 and 12 can have a yoke 15 (referred to as a “slotless” arrangement) installed on the same plane. In the case of this configuration, a permanent magnet shape 9A is required as shown in FIG. 4F. Compared with other arrangements, this arrangement reduces the generation of radial forces, but significantly reduces the degree of negative stiffness instability and reduces inductance, thus increasing the rotational speed. can do. This is because less back electromotive force is generated. If the mass of the impeller is larger or the size of the coil is larger, the occupied space of this magnetic bearing type becomes larger.

  Alternatively, the coil can be placed in a slot 15A in a yoke (referred to as a “slot type”) where the yoke is radially inward as shown at 15C, 15D in FIG. 4G. Extend to. In the case of this configuration, it is preferable to use the magnet shape 9B shown in FIGS. 4H and 4I in order to reduce the generated cogging torque. With this stator type, larger bearings and torque can be generated, but speed is limited due to the relatively large inductance. However, the rotational speed can be made sufficiently fast for this application.

  Additionally or alternatively, to improve the magnetic flux density, the magnet can be configured in a Halbach array, as shown in FIG. 4J. In this case, each individual magnet is made up of a plurality of smaller magnets with slightly different radial polar orientations.

  During use, the driver magnet 9 is arranged such that its magnetic pole is aligned perpendicular to the axis of the impeller 3. In this case, adjacent magnets have magnetic poles aligned in the opposing direction. By doing so, an alternating magnetic field is created around the outside of the impeller 3 as indicated by the arrow 10. More specifically, in this example, the magnetic field extends radially outward from the permanent magnet 9. In this case, as shown in the figure, the direction of the magnetic field alternating between them is directed outward in the radial direction or inward in the radial direction.

  An example of a method for controlling the rotation and position of the impeller will be described below with reference to FIGS. 5A and 5B which are sectional views of the circumference of the coils 11 and 12 and the yoke 15 for indicating the directions of the coils 11 and 12. To do. In this example, the first set of coils 11 provides rotational torque (referred to as a “motor coil”) and the second set of coils 12 serves as a bearing function (referred to as a “bearing coil”). I will provide a.

  More specifically, in the case of FIG. 5A, a current flows through a pair of opposed motor coils 11A and 11B of the motor winding as shown in the figure. Thereby, a magnetic field indicated by an arrow 16A is generated, and a Lorentz force is generated in the coil as indicated by an arrow 16B. Since the coil is fixed to the stator, this causes the impeller body to rotate in the direction of the arrow 17. Therefore, the impeller can be rotated by supplying an appropriate current to the motor coil.

  In the case of FIG. 5B, a current flows through the pair of opposed coils 12A and 12B of the bearing winding as shown in the figure. As a result, Lorentz force is generated in the coils 12A and 12B as indicated by an arrow 16B. Since the coils 11 and 12 are fixed to the stator yoke 15, the impeller 3 thereby moves laterally with respect to the cavity shaft 7 as indicated by an arrow 18. Similarly, the impeller can be moved laterally by supplying an appropriate current to the bearing coil.

  The lateral movement is usually performed by a control device. FIG. 6 shows an example. In this example, the controller includes a processing system 20 having a processor 21, a memory 22, and an external interface 23 coupled together through a bus 24. An optional input / output device 25 can also be installed.

  The processing system 20 is coupled to three sensors 26A, 26B, 26C and a signal generator 27 via an external interface 23. The signal generator 27 is a pair of opposed coils as shown generally for motor coils 11A, 11B, 11C, 11D, 11E, 11F and bearing coils 12A, 12B, 12C, 12D, 12E, 12F, respectively. Are coupled to the motor coil and the bearing coil. As shown, the coils are arranged as pairs of opposed position coils 11A, 11B; 11C, 11D; 11E, 11F and 12A, 12B; 12C, 12D; 12E, 12F.

  In use, the processor 21 determines from the data stored in the memory 22 the current that must be supplied to the motor coil to achieve the required rotational speed. In the case of a heart pump, one speed is preset before implanting the device. It will be appreciated that this can be accomplished by storing information defining a pre-set speed in memory 22 and using a remote processing system coupled to I / O device 25 or external interface 23. Will be able to.

  Alternatively, several speeds can be set while the pump is in use. This can be done by using a suitable detection system, for example via a wired or wireless connection with the input / output device 25 or external interface 23, or in response to an external stimulus such as a potential heart rate rise. It can be carried out.

  In any case, a signal representing the current to be supplied is supplied to the signal generator 27, which operates to generate the appropriate current, which in turn is the motor coil 11A, 11B. , 11C. This usually involves the operation of a pair of motor coils in a predetermined sequence to cause the impeller to perform the desired motion.

In particular, consider the above configuration including eight equally spaced permanent magnets 9 and six equally spaced motor coils and bearing coils 11, 12 as shown.
During rotation, the motor coil 11 pair is driven by a three-phase current. Accurate rotational speed can be monitored by a suitably installed Hall effect sensor mounted to detect changes in the position of the driver magnet relative to a sensor fixed at the housing position. Alternatively, the counter electromotive force generated in the first set of magnets can be related to the rotational speed. Once this speed is determined, this speed can be fed back to the controller to maintain the set rotational speed.

  In the case of controlling the position of the impeller in the lateral direction, this control can be performed by causing the processor to determine position information from the sensors 26A, 26B, and 26C. To perform this control, for example, by providing a suitable aperture generally within the housing 1 (not shown) in the interior surfaces of the cavities 2A, 2B, as shown in FIGS. 7A, 7B, and 7C, A sensor is installed in the housing.

  These drawings detail the preferred technique used to determine the position of the impeller. Around each of the cavities 2A and 2B, a set of apertures are provided in the main body portions 1A and 1B at equal intervals in the circumferential direction. In use, only one set of sensors 26A, 26B, 26C can be used. This is because only one set of sensors is sufficient to determine the position of the impeller 3 in the lateral direction (x, y). However, it may also be advantageous to include sensors 26D, 26E, and 26F in all apertures in order to determine the position of the impeller with all degrees of freedom and provide some positioning redundancy. There is.

  In the preferred embodiment, each set of apertures is arranged at an interval such that the sensors 26A, 26B are arranged along the x-axis and y-axis having an origin coincident with the cavity axis. The third sensor 26C is located in the middle between the −x axis and the −y axis. The sensors 26A, 26B, 26C operate by measuring the distance “d” between each sensor and the surface 33 of the impeller 3, as shown in FIG. The distances measured for the three sensors 26A, 26B, 26C can be understood by anyone skilled in the art by measuring these distances to the x, y and z planes so that the impeller body Used to determine the position of In the case of this example, since it is only necessary to measure the position of the impeller 3 in the xy plane, this can theoretically be performed only by the sensors 26A and 26B. In practice, the third sensor is intended to be unaffected by changes in the position of the impeller 3 along the cavity axis.

  The distance between the sensors 26A, 26B, 26C and the impeller surface 33 can be measured in a number of ways. Thus, for example, preferably the sensors 26A, 26B, 26C are preferably Hall effect sensors that can detect the magnetic field generated by a permanent magnetic sensor target that can be made from the driver magnet 9. Next, the processor 21 can use the magnitude of the current generated by the Hall effect sensor to obtain the position of the impeller 3.

  Alternatively, as can be understood by one skilled in the art, each sensor 26A, 26B, 26C can be made from a radiation source, such as an LED laser, and a corresponding photodetector.

  As another method of measuring the position of the surface of the impeller 3, as shown in FIG. 9, a surrounding plate 3 </ b> D can be mounted on the blade 34. In this case, the position of the impeller 3 can be measured by measuring the distance d1 between the magnetic sensor target embedded in the surrounding plate 3D and the sensors 26A, 26B, and 26C.

  This method is advantageous in that the distance d1 between the permanent magnetic sensor target and the sensors 26A, 26B, 26C is shorter than the distance d between the surface 33 and the sensors 26A, 26B, 26C. In addition to this, when measuring the distance between the surface 33 and the sensors 26A, 26B, 26C, the vanes 4 periodically pass between the sensors 26A, 26B, 26C and the surface 33, which Affects the measured value. As a result, the use of the shroud 3D allows the processor to detect the impeller position more quickly and more accurately with higher resolution. However, if the surrounding plate 3D is used, the effect of the impeller 3 may be reduced, and turbulence may be generated in the cavities 2A and 2B. This is undesirable for certain applications, such as when the system is used as a heart pump.

  Another way of sensing the position of the impeller within the cavity 2 is that the voltage and current waveforms of each motor coil and / or bearing coil can be monitored by the processing system 20 for sensing the position of the impeller. Related to so-called “self-sensing” technology. The component of the current waveform is related to the circuit inductance, which changes opposite to the movement of the permanent driver magnet 9 in the air gap 8A. By recording and analyzing the voltage of the counter electromotive force generated by the motor, the rotational position can be sensed by a signal from the bearing coil that determines the position. In this example, it can be seen that the bearing coil 12 and the motor coil 11 form a sensor 26.

  In any case, when the processing system 20 detects a lateral movement of the impeller such that the shaft of the impeller 3 and the cavity shaft 7 are no longer in alignment, the processor must supply the selected pair of bearing coils 12. A predetermined algorithm is used to generate the current that must be generated. This one indication is transferred to the signal generator 27, which responds by generating appropriate currents and applying these currents to a selected one of the bearing coils 12. The current in the coil 12 moves the impeller body, as will be described below, thereby realigning the impeller body axis with the cavity axis.

  It will be appreciated that the sensor 26 can also determine the rotational position of the impeller 3 so that the processing system 3 can monitor and adjust the rotational speed.

  In addition, other magnetic bearing technologies such as those based on reluctance type magnetic theory can be used. For this configuration, those skilled in the art will appreciate that a slightly different control tactic and a slotted stator configuration with 6 coils around a 6 iron-only core is required.

  More specifically, it is preferable to position the impeller so that the magnet 9 is located inward in the radial direction of the motor coil and the bearing coils 11 and 12. This is because in this way there is an optimal coupling between the coils 11, 12 and the permanent magnet 9, thereby providing optimal efficiency and hence stiffness in the radial direction. This can be done in a number of ways depending on the particular implementation.

In addition to controlling the lateral position of the impeller 3, it is also necessary to reliably maintain the position of the impeller along the cavity axis ("axial position").
In the case of the above example, the permanent driver magnet 9 is attached to the magnetic field generated in the motor coil and bearing coils 11, 12. Thereby, a certain amount of return movement to the axial null position is performed. More specifically, when the impeller is displaced along the cavity axis, the attractive force of the coils 11 and 12 pushes the impeller back to the optimal position by an effect called passive stability.

  In general, this alone is sufficient in most cases to maintain axial alignment, especially when the fluid pressure is approximately equal in both cavities 2A, 2B. However, other or another axial alignment can be achieved by using an additional support magnet. In this case, the support magnet can be installed in the housing with the corresponding magnet installed in the main body of the impeller 3.

  This can be done with various magnet configurations. Thus, for example, a flat (parallel to the radial axis) or frusto-conical permanent magnet 35 can be placed along the circumference of the housing parts 1A, 1B, as shown in FIG. This can be done with one suitably shaped magnet or a series of circumferentially spaced magnets 35. In any case, the support magnets 35A, 35B cooperate with corresponding permanent support magnets 36A, 36B located in the impeller body 3. If the magnets are configured with similar polarities facing each other, the support magnet 35 repels the support magnet 36, thereby moving the impeller body to the center of the cavity.

  Therefore, when the impeller 3 moves in a direction parallel to the cavity axis 7, the distance between the support magnet 35 and the corresponding support magnet 36 is shortened, thereby increasing the resulting repulsive force, thereby reducing the impeller. Move toward the center of the cavity corresponding to the optimal position.

Even if the impeller is tilted by the gyroscope effect, the force to push the impeller back to a stable position increases.
Alternatively, in this example, a coil can be used in place of the magnet 35. In this case, by configuring the support magnet 36 in a manner similar to that of the driver magnet 9, the axial bearing can be further used to drive the impeller in a manner similar to that described above.

  One skilled in the art will understand that some form of active magnetic suspension must be implemented with at least one degree of freedom as described by the Earnshaws Theorem. Using this arrangement, the polar axis of the housing magnet and the rotor magnet will have an angle with respect to the impeller axis. However, the rotor and / or housing magnet can be physically perpendicular to the impeller axis, in which case the angle is preferably 0 degrees and the magnetic poles are parallel to the impeller axis. It is desirable. Preferably, this angle corresponds to the angle of the cone forming the impeller 3 in order to narrow the gap between the rotor permanent magnet and the housing permanent magnet. However, it is appropriate if it is within the range of 0 to 65 degrees. This angle must be positioned to provide the maximum reaction to the axially changing load applied by the pumped fluid. This angle may actually be different from the rotor magnet to the housing magnet direction to provide either radial support or axial support.

This therefore provides a self-balancing technique for maintaining the impeller position in the axial direction.
In the above case, when the permanent magnet 36 is located on the impeller main body, the closer to the magnet 35 in the housing portions 1A, 1B, the greater the effect of the magnet. Therefore, the magnet 36 can be mounted on a shroud located on the blade 4. FIG. 11A shows an example of this state. Those skilled in the art will understand that this allows the distance measurements obtained by the sensors 26A, 26B, 26C to be obtained by measuring the distance to the magnet 36 mounted on the shroud. can do. FIG. 11B shows the appearance of the housing 1. In the case of this example, the housing can incorporate the support magnet 35.

In any case, the inclusion of an additional passive permanent magnet in the system generally reduces the axial force applied to the impeller, thus reducing the current required to maintain the axial impeller suspension. Tesumu.
Second Specific Example In the case of the second specific example, compared to the first example, the pump can assist the natural function of the left ventricle with, or instead of, a slow rotational speed or impeller diameter. Can work to be.

  This can be achieved by using a double impeller configuration as two pumps in series rather than in parallel as in the first specific example (hereinafter referred to as XLVAD). Therefore, in the above example, fluid enters the first inlet volute 5C directly from the left ventricle / atrium. The fluid passes through the inlet 5A by vanes 4A on the impeller 3A in the cavity 2A which serves to bias the fluid in the direction of the outlet 6A. The fluid then moves through the crossover volute from the outlet 6A to the inlet 5B and therefore enters the pump cavity 2B. The vanes 4B send fluid into the circulatory system through the outlet 6B and via the cannula to the aorta. The fluid is separated from the cavities 2A, 2B by the gap gap 8A.

  By operating the pump as two centrifugal pumps in series, the pressure of the fluid is increased by two stages. Therefore, the fluid entering the cavity 2A must increase in pressure by about half of the increase in total output pressure required while the fluid moves from the inlet 5A to the outlet 6B. Therefore, the fluid entering the cavity 2B through the inlet 5B is already half the desired total pressure value and can therefore increase the other half of the total pressure required in the cavity 2B.

  As a result, the rotation speed of the impeller can be made slower than that of the LVAD example. The reduction in speed is about LVAD RPM / √2. This reduction in rotational speed significantly reduces the level of shear stress in the pump and potentially reduces the level of hemolysis.

  As another method, as described in fluid mechanics theory, the impeller rotational speed can be kept constant by reducing the outer diameter of the impeller in order to increase the required pressure.

  When this configuration is used, the pressure distribution between the two cavities 2A and 2B may be unbalanced, and an axial force may be generated in the direction of the cavity axis 7 in the direction of the cavity 2A where the pressure is low. Similarly, fluid may leak from the cavity 2B to the cavity 2A through the gap gap 8A due to a pressure difference between the cavities 2A and 2B.

  Therefore, an impeller suspension method is typically used that cancels the axial force and thus reduces the level of leakage flow that occurs. However, this method need not necessarily be used.

  12A to 12F show the configuration of the first example for the X-LVAD operation. In this example, a reference number similar to the above reference number, which is 50 larger, is used. Therefore, each element of the pump will not be described in detail.

  In the case of this example, the impeller 53 is completely suspended in the axial direction, and rotates around the hollow shaft 57 by an axial magnetic motor bearing. Radial freedom is limited by the combination of passive magnetic forces generated by an active axial bearing coupled with a fluid bearing located at 58. In the case of a hydrodynamic bearing, the gap gap 58A that serves to significantly reduce the flow of fluid from the cavity 52B to the cavity 52A needs to be the narrowest. It will be appreciated that the cavity 52 is shaped to accommodate other impeller shapes accordingly.

  In this example, the impeller 53 is cylindrical and uses a shroud 53D to improve hydraulic efficiency and provide an area for placing magnetic material. The vane 44A is constructed by correctly selecting the vane angle and height in order to increase the pressure by half the desired total pressure increase required by the pump. In an example, the pressure increase from the inlet 55A to the outlet 56A is about 50 mmHg.

  Fluid exits the first stage through outlet 56A and enters “crossover” volute 56C. This volute efficiently transfers the fluid to the second stage inlet 55B. The fluid entering the second stage is half of the total pressure and requires vanes 54B to raise the latter half of the total pressure. The vanes 54B can have slightly different profiles so that they can be used at different inlet conditions.

  In this example, the magnet system is used for both axial suspension and rotation of the impeller 53 including the cavity 52. An example of this magnet system will be described below with reference to FIGS. 12G to 12L.

  In this case, the two slotted stators 65 </ b> A and 65 </ b> B are located above and below the impeller 53 in the axial direction. Magnetic fields generated by the coils 61A and 61B wound around the core 65C in the stators 65A and 65B are coupled to a special-shaped permanent driver magnet 59 embedded in the surrounding plate 53D of the impeller 53.

  In this example, four driver magnets 59A are located on the first end 53A of the impeller that includes a corresponding set of driver magnets 59B located on the second end 53B. However, other numbers of magnets can be used.

  In the case of a motor function, the same current is supplied to the coils 61A and 61B located in the top and bottom stators 65A and 65B. In this example, six coils 61A and 61B are shown, but other numbers of coils can be used.

  In the case of the bearing function, when the current supplied to the coil 61A increases, the current supplied to the coil 61B correspondingly decreases, thereby increasing the magnetic attractive force to the coil 61A and decreasing the magnetic attractive force to the coil 61B. To do. Therefore, a force is generated along the cavity axis 57 toward the coil 61 </ b> A, and therefore this force can be used to change the position of the impeller 53 along the cavity axis 57. This control is again performed by determining the position of the impeller 53 using a suitable sensor 76 coupled to the processing system 70. Next, the operation is performed in a manner similar to that described with reference to FIGS. 5A, 5B and 6, but this operation has already been described and will not be described in detail.

  Another way to install the two sets of driver magnets 59A, 59B is to allow the stator 65A to operate only as a magnetic bearing coupled to the iron on the first end 53A of the impeller. In this case, rotational torque is only supplied by the bottom stator 65B having more iron cores coupled with a suitable number of driver magnets 59B embedded in the end 53B.

  In this example, the sensor 76 is required for an axial type magnetic bearing, so a target is set on the flat impeller shroud 53D to directly sense only axial movement. Can be mounted as follows.

  In another example, the magnetic field generated by the coils 61A, 61B is directly coupled to the iron embedded in the enclosure 55D at either end 53A, 53B of the impeller 53. This allows only axial bearing control to be performed and can therefore be used to control the position of the impeller 53 along the cavity shaft 57. By coupling the three-phase motor with a magnet 59 embedded in the cylindrical circumference of the impeller 53, rotational torque is supplied in a manner similar to that already described. This can be achieved using an arrangement similar to that described in FIGS.

In one example, the motor has six coils wound around six core stators located within the housing, facing radially outward from the outer periphery of the impeller.
In all the above examples, the radial motion can be controlled in many different ways. For example, such control can be performed by an appropriate set of coils installed on the housing 51. As already described with reference to FIGS. 1-11, this coil may include an additional set of driver coils or control coils.

  Alternatively, radial movement can be limited by using a hydrodynamic bearing in the gap gap 8A between the impeller 3 and the housing 8. In this case, the cylindrical circumference of the impeller can be made from a large number of small tapered wedges 90. FIG. 13G shows an example.

Preferably, the wedge 90 has a rounded edge to reduce blood component damage. However, when the edge is rounded, the rigidity of the fluid bearing is lowered. Combining these wedges with relative rotational speeds creates thrust as the fluid is tightened through the tapered gap as described by Reynold's lubrication theory. This radial thrust is used to balance all radial forces generated within the pump.
Third Specific Example A third specific example relates to a single pump called BiVAD that can assist or replace the function of both the left and right ventricles of the heart.

  An example of this pump will be described below with reference to FIGS. 13A to 13H. In these figures, like reference numbers that are more than 100 are used to indicate similar integers to those shown in the first particular example.

  In this example, fluid is pumped from the left ventricle into the cavity 102A via a cannula connected to the inlet 105A. The fluid enters the cylindrical impeller 103 and its vanes 104A urge the fluid through the volute 137A in the direction of the outlet 106A and return to the circulatory system through a cannula connected to the aorta. This provides sufficient flow rate and pressure required by the systemic circulatory system to increase 100 mm Hg pressure at a flow rate of 5 L / min in some cases.

  At the same time, fluid is pumped from the right ventricle into the cavity 102B via a cannula connected to the inlet 105B. The fluid flows to the side surface 103B of the impeller 103, and the impeller has vanes 104B that urge the fluid in the direction of the outlet 106B through the volute 137B. In this case, the vanes 104B are designed to provide a flow rate and pressure suitable for the pulmonary circulatory system that, in one example, increases the pressure by 20 mmHg at a flow rate of 5 L / min. Fluid is delivered through a suitable cannula connected to the pulmonary artery.

In this example, axial suspension and impeller drive are performed as described in the first or second specific example.
In the example of FIG. 13, the impeller 103 is driven by a coupling magnetic field generated by the coils 111A and 111B wound on the stators 115A and 115B to the driver magnets 109A and 109B embedded in the surrounding plate 103D. Rotate.

  Alternatively or additionally, the axial position can be controlled by a pure axial magnetic bearing located in the housing 101B that is coupled to the iron-only target in the shroud 103D.

  It can be appreciated that other motor coils and bearing coils as described in the above embodiments can be used when other means of controlling the position of the impeller along the cavity axis are used. right.

  Again, control of the radial position can be accomplished using a suitable coil configuration that cooperates with the driver magnet 109 located within the central portion 103C of the impeller 103. Alternatively, this control can be performed by a hydrodynamic suspension as described in the second specific example.

  In the case of the following example, the narrow gap gap 8A and the short cylindrical portion in this region reduce the flow of leakage from the high pressure side to the low pressure side by creating an appropriate resistance to the fluid flow. And therefore less pollution.

  As shown in FIGS. 13H-13J, differential pressure and flow characteristics are achieved by the dimensions of the set of vanes 104A, 104B. More specifically, since the impeller operates at one rotational speed, a pressure difference can be created by providing different impeller blades 104A and 104B on the high pressure impeller side 103A and the low pressure side 103B.

In this case, as shown in FIG. 13J, the length of the blade 104B on the impeller portion 103B is shorter than the length of the blade 104A on the impeller portion 103A.
In the case of this example, when the impeller 103 is rotating at 2200 rpm, the required flow velocity and pressure can be obtained by the following dimensions.

・ Bane 104A Ll = 22mm
・ Radius of blade end 103A Rl = 25mm
・ Bane 104B Lr = 11mm
・ Radius of impeller end 103B R = 12.5mm
In this example, it should be understood that this pressure differential minimizes blood flow from the left side of the pump to the right side. However, since these values represent the flow of blood that has been blown with oxygen to blood that has not been blown with oxygen, this does not represent a medical problem.

  It will be appreciated from the above description that a number of different axial and radial bearings can be provided along with a number of different rotary drives. These bearings can be used in any combination with a cylindrical or double conical impeller.

Thus, for example, the system can use the various combinations described below.
A passive axial suspension by a magnetically coupled permanent magnet in a pump housing including a permanent magnet in the impeller. A passive axial suspension by a physical coupling between the housing and the impeller indicated by reference numerals 150 and 151 in FIG. Active axial suspension by magnetically coupled coil in pump housing with permanent magnet or iron in impeller Active radial suspension by magnetically coupled coil in pump housing with permanent magnet in impeller Fluid between impeller and housing Passive radial suspension due to mechanical effects-Impeller rotation by a magnetic coupling coil in a pump housing that contains a permanent magnet in the impeller Many modifications and modifications will readily occur to those skilled in the art. All such changes and modifications that will readily occur to those skilled in the art fall within the spirit and scope of the present invention which has been broadly described.

  Therefore, while the above description focuses on the use of a fluid pump as a cardiac assist device, this fluid pump is for other purposes and all fluid pumping where pressure and flow rate fall within the operating parameters of the device. It can also be used for applications.

(A)-(E) are the schematic sectional drawing of an example of the fluid pump which incorporates an impeller, an end view, a top view, a perspective view, and an exploded perspective view. (A)-(F) are schematic plan views of examples of inlet and outlet volutes for use with the pumps of FIGS. 1 (A) -1 (E). (A)-(D) are the schematic perspective view and top view of an example of the impeller for using with the pump of FIG. 1 (A) -FIG.1 (E). (A)-(J) are schematic diagrams of examples of magnets for use in the pumps of FIGS. 1 (A)-(E). (A), (B) is a schematic plan view of the magnetic field which a coil generate | occur | produces with the pump of FIG. 1 (A)-FIG. 1 (E), and the corresponding motion of an impeller. FIG. 2 is a schematic view of an example of a control device for controlling the pumps of FIGS. (A)-(C) are the schematic perspective view, the top view, and the side view of an example of the sensor for using with the pump of FIG. 1 (A) -FIG.1 (E). 4 is a schematic diagram of an example of sensing the position of the impeller of FIG. 4 is a schematic diagram of an example of sensing the position of the impeller of FIG. 1 is a schematic illustration of an example of a fluid pump having an additional axial suspension. (A), (B) is a schematic perspective view of an example of an impeller and a housing for use in a pump having an active axial suspension. (A)-(L) are schematic diagrams of another example of a fluid pump incorporating an impeller. (A)-(J) are schematic diagrams of another example of a fluid pump incorporating an impeller. 1 is a schematic cross-sectional view of a fluid pump having an axial bearing.

Claims (78)

A fluid pump,
a) a housing forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a housing having a set of coils for generating a magnetic field;
b) an impeller located in the cavity,
i) in use, a body forming an impeller axis substantially parallel to the cavity axis;
ii) a number of vanes located on the body for urging fluid from the inlet to the outlet during use;
iii) an impeller having a number of driver magnets located in the magnetic field during use;
c) at least two sensors adapted to detect the position of the impeller within the cavity;
d) a radial bearing for controlling the position of the impeller in a direction perpendicular to the cavity axis;
e) radial coupling to control the position of the impeller in a direction parallel to the cavity axis;
f) In use, a controller coupled to the first and second sets of sensors and coils to control the magnetic field and thereby control rotation of the impeller about the impeller axis And fluid pump including. The axial coupling is
a) a second set of coils for generating a second magnetic field;
b) a plurality of axial support magnets provided in the main body and located in use in the second magnetic field, wherein the controller controls the second magnetic field, thereby The fluid pump according to claim 1, wherein movement of the impeller in a direction parallel to the cavity axis is controlled. The axial coupling is provided in the first set of coils and the body and includes a number of axial support magnets located in use in the magnetic field during use; The fluid pump of claim 1, wherein the fluid pump controls a motion of the impeller in a direction parallel to the cavity axis. The axial coupling is
a) a set of magnets coupled to the housing to generate an axial control field; and b) provided within the body and located in use within the axial control field. The fluid pump of claim 1 including at least one of a plurality of axial support magnets thereby restricting movement of the impeller in a direction parallel to the cavity axis. The fluid pump according to any one of claims 2 to 4, wherein the supporting magnet in the axial direction is the driver magnet. The axial coupling is
a) a first bearing member coupled to the housing;
and b) a second bearing member coupled to the impeller, wherein the first and second bearing members cooperate to thereby limit movement of the impeller in a direction parallel to the cavity axis. 2. The fluid pump according to 1. The radial bearing is
a) the inner surface of the housing;
b) when a fluid is pumped during use, a boundary layer is formed between the inner surface portion and the outer surface portion, thereby limiting the movement of the impeller in a direction perpendicular to the cavity axis. The fluid pump according to any one of claims 1 to 6, comprising at least a part of an outer surface of the impeller having a shape that cooperates with an inner surface. The radial bearing includes a second set of coils for generating a second magnetic field, and the controller controls the third magnetic field by a signal from the sensor, thereby perpendicular to the cavity axis. The fluid pump according to claim 1, wherein the movement of the impeller in a specific direction is controlled. The fluid pump of claim 1, wherein the fluid pump includes at least one sensor located at a first end of the cavity and at least two sensors located at a second opposing end of the cavity. The fluid pump according to item 1. The fluid pump according to any one of claims 1 to 9, wherein the size of the blade is selected to control at least one of the fluid pressure and the flow velocity at the outlet. The dimensions are
a) the height of the blade,
b) the diameter of the impeller,
c) the length of the blade,
d) the width of the blade,
e) the angle of the inlet and outlet vanes,
f) the shape of the blade,
11. The fluid pump of claim 10, comprising g) at least one of the number of vanes. a) the housing is
i) at least two fluid inlets;
ii) at least two fluid outlets;
b) the impeller
i) at least two body portions;
ii) first and second sets of vanes located on the first and second body portions, respectively, each set of vanes biasing fluid in use from each inlet to each outlet. The fluid pump according to any one of 1 to 11. The impeller cooperates with the cavities to form first and second cavity portions, each cavity portion including an inlet, an outlet, and the impeller, respectively, wherein the cavities are fluids between the cavity portions. The fluid pump of claim 12, wherein the fluid pump is configured to substantially prevent movement. 14. A fluid pump according to claim 12 or 13, wherein the first and second sets of vanes each have substantially the same dimensions, thereby supplying fluid at the outlet at substantially the same pressure and flow rate. 14. A fluid according to claim 12 or 13, wherein the first and second sets of vanes each have different dimensions, thereby supplying fluid at the respective first and second pressures at each outlet. pump. The fluid pump of claim 15, wherein the first outlet is coupled to the second inlet. 17. The cavity according to any one of claims 1 to 16, wherein the cavity is substantially rotationally symmetric with respect to the cavity axis and the coils are circumferentially spaced around the cavity. Fluid pump. The body is substantially rotationally symmetric with respect to the impeller, and the driver magnets are located radially outward from the impeller and spaced circumferentially around the impeller shaft. The fluid pump according to any one of 1 to 17. The fluid pump according to claim 18, wherein the driver magnet is located inward in the radial direction of the coil. The fluid pump of claim 2, wherein the first set of coils is located radially inward of the second set of coils. The fluid pump according to claim 1, wherein the coil is mounted on a yoke. The fluid pump of claim 21, wherein the yoke includes a slot for receiving the coil. The set of coils includes three pairs of first coils, the first coils in each pair are positioned facing each other in the circumferential direction, and the control device is in a corresponding direction. 23. A fluid pump according to any one of the preceding claims, wherein an electric current can be passed through the coil, thereby rotating the impeller. The control device is
a) Determine the required impeller rotation speed,
b) determining a control signal sequence for each pair of first coils;
24. A fluid pump according to claim 23, adapted to provide each control signal sequence to each pair of first coils to move a driver in a predetermined direction and thereby rotate the impeller. . The second set of coils includes three pairs of second coils, the second coils in each pair are located facing in the circumferential direction, and the control device corresponds to 3. A fluid pump according to claim 2, adapted to allow current to flow through the coil in an opposing direction, thereby moving the driver member radially relative to the cavity axis. The control device is
a) monitor the sensor;
b) determining any movement of the driver shaft in the radial direction relative to the cavity shaft;
c) selecting one or more pairs of second magnets;
d) generate a control signal for each selected pair;
26) adapted to supply said control signal to each said selected pair for moving said driver in a predetermined direction and thereby moving said driver axis in the direction of said cavity axis The fluid pump described. The control device is formed of a processing system having a memory and a processor, and the processing system generates a control signal for controlling the magnetic field generated by the coil according to a predetermined algorithm stored in the memory. 27. A fluid pump according to any one of claims 1 to 26 adapted to do so. 28. The fluid pump of claim 27, wherein the processing system is coupled to a signal generator and the control signal is formed by causing the signal generator to supply a predetermined current to the coil by the processing system. . The driver magnet includes eight circumferentially spaced permanent magnets, the magnetic poles of the magnet are aligned in a direction perpendicular to the driver shaft, and the direction of magnetic pole alignment is adjacent The fluid pump according to any one of claims 1 to 28, wherein the fluid pump is disposed so as to be reversed. The body is
a) two body ends,
b) a plurality of vanes located on the end of the body, the vanes extending from the surface of the end of the body in a direction substantially parallel to the driver shaft and radially outward from the driver shaft 30. The fluid pump according to any one of claims 1 to 29, wherein the fluid pump is located in a circumferential direction and spaced circumferentially around the driver shaft. 31. A fluid pump according to claim 30, wherein each body end is substantially conical. 32. A fluid pump according to claim 30 or 31, wherein the body includes a generally cylindrical central body portion positioned between the two body ends, and the driver magnet is located within the cylindrical central body portion. . The cavity includes first and second cavity ends, each cavity end comprising:
a) an inlet located along the cavity axis;
b) an outlet that is oriented perpendicular to the cavity axis and is radially offset from the cavity axis;
33. The method of claim 31 or 32, wherein the blade is adapted to urge fluid from the inlet to the outlet in response to rotation of the impeller and has a generally conical shape to cooperate with the impeller. The fluid pump described. The impeller and the cavity cooperate to substantially prevent fluid from flowing from one cavity end to the other cavity end, and the vanes on each body end are at a certain height. 34. The fluid pump of claim 33, having a length, thereby controlling the pressure or flow rate at the outlet in each end. 35. The method of claims 30-34, wherein the pump includes at least two sensors located within at least one of the cavity ends, thereby measuring the distance between the sensors and the surface of each body end. The fluid pump according to any one of the above. 36. The fluid pump of claim 35, wherein the impeller includes a shroud coupled to the vanes, and the sensor is adapted to determine a position of the shroud. 37. The pump includes at least three sensors positioned radially outward from the cavity axis and spaced circumferentially around the cavity axis. The fluid pump described in 1. 38. Any one of claims 35 to 37, wherein the sensor includes a radiation source adapted to emit radiation in the direction of the surface of each body end, and a detector for detecting reflected radiation. The fluid pump described. 38. A fluid pump according to any one of claims 35 to 37, wherein the impeller includes a position magnet, and the sensor is formed from a Hall effect sensor adapted to measure a magnetic field generated by the position magnet. 40. The fluid pump according to claim 39, wherein the position magnet is the driver magnet. The fluid pump according to claim 6, 9 or 15, wherein the support magnet has a substantially conical or truncated cone shape. The fluid pump according to any one of claims 1 to 41, wherein the impeller and the cavity have a substantially cylindrical shape. The impeller includes one or more wedges located on an outer periphery of the body, thereby cooperating with an inner surface to hydrodynamically control the position of the impeller in a direction perpendicular to the cavity axis. Item 8. The fluid pump according to Item 7. 44. A fluid pump according to claim 43, wherein the wedge is provided within a central body portion. The fluid pump according to any one of claims 2 to 5, wherein the axial support magnet is formed of a magnet material located in a magnetic field. 46. A fluid pump according to claim 45, wherein the axial support magnet is formed from soft iron. 31. A fluid pump according to claim 30, wherein the impeller includes a shroud on each body end. 48. The fluid pump of claim 47, wherein each shroud includes a driver magnet. 48. The fluid pump of claim 47, wherein each shroud includes an axial support magnet. The fluid pump of claim 2, wherein the pump includes a set of second magnets located within each of the two cavity ends. A fluid pump,
a) a housing forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a housing having first and second sets of coils for generating first and second magnetic fields;
b) an impeller located in the cavity,
i) a main body forming an impeller shaft substantially parallel to the hollow shaft in use;
ii) a number of vanes located on the body for urging fluid from the inlet to the outlet during use;
iii) an impeller having a number of driver magnets located in the first and second magnetic fields during use;
c) at least two sensors adapted to detect the position of the impeller within the cavity;
d) a controller coupled to the first and second sets of sensors and coils, in use;
i) controlling the first magnetic field, thereby controlling the rotation of the impeller about the impeller axis;
ii) a fluid pump comprising a controller for controlling the second magnetic field and thereby controlling the movement of the impeller in a direction perpendicular to the cavity axis. 52. The fluid pump of claim 51, wherein the controller controls the second magnetic field, thereby controlling the movement of the impeller parallel to the cavity axis. 52. The fluid pump of claim 51, wherein the fluid pump includes an axial coupling to limit movement of the impeller in a direction parallel to the cavity axis. A fluid pump,
a) a housing having an inner surface forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a housing having a set of coils coupled to the housing for generating a magnetic field;
b) an impeller located in the cavity,
i) a body forming an impeller shaft;
ii) a number of vanes located on the body for urging fluid from the inlet to the outlet during use;
iii) a number of driver magnets located in the magnetic field during use;
iv) an outer surface, when in use, fluid is pumped, a boundary layer is formed between the inner surface portion and the outer surface portion, thereby limiting movement of the impeller in a direction perpendicular to the cavity axis An impeller having an outer surface shaped such that at least a portion of the outer surface cooperates with a correspondingly shaped portion of the inner surface;
c) an axial coupling to limit the movement of the impeller in a direction parallel to the cavity axis;
d) a fluid pump including a controller for controlling the first magnetic field and thereby rotating the impeller about the impeller axis. The axial coupling is
a) a second set of coils for generating a second magnetic field;
b) at least two sensors for sensing the position of the impeller within the cavity, wherein the controller is coupled to the second set of sensors and coils and is in use 55. A fluid pump according to claim 53 or 54, which controls the second magnetic field and thereby controls the movement of the impeller in a direction parallel to the cavity axis. The axial coupling is
a) a set of magnets coupled to the housing to generate an axial control field; and b) provided within the body and located in use within the axial control field. 55. A fluid pump according to claim 53 or 54, comprising at least one of a number of axial support magnets thereby restricting movement of the impeller in a direction parallel to the cavity axis. The axial coupling is
a) a first bearing member coupled to the housing;
b) a second bearing member coupled to the impeller, wherein the first and second bearing members cooperate to thereby limit movement of the impeller in a direction parallel to the cavity axis. Item 55. The fluid pump according to Item 53 or 54. A fluid pump,
a) a housing forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a housing having a set of coils for generating a magnetic field;
b) an impeller located in the cavity,
i) in use, a body forming an impeller axis substantially parallel to the cavity axis;
ii) a number of vanes located on the body for urging fluid from the inlet to the outlet during use;
iii) an impeller having a number of driver magnets located within the first magnetic field during use;
c) at least two sensors adapted to detect the position of the impeller within the cavity;
d) a controller coupled to the sensor and the set of coils, wherein in use, the magnetic field is controlled, thereby i) controlling the rotation of the impeller about the impeller axis;
ii) a fluid pump including a control device that controls movement of the impeller in a direction parallel to the cavity axis. In the fluid pump,
a) a housing forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a set of coils for generating a first magnetic field;
iv) a housing having a set of magnets for generating an axial control magnetic field;
b) an impeller located in the cavity,
i) in use, a body forming the impeller axis substantially parallel to the cavity axis;
ii) a number of vanes located on the body for urging fluid from the inlet to the outlet during use;
iii) a number of driver magnets located within the first magnetic field during use;
iv) an impeller having a number of support magnets located in the axial control field and thereby restricting the movement of the impeller in a direction parallel to the cavity axis;
c) a fluid pump coupled to the set of coils for controlling the first magnetic field and thereby controlling the rotation of the driver about the driver axis. In the fluid pump,
a) a housing forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a first bearing member;
iv) a housing having a set of coils for generating each magnetic field;
b) an impeller located in the cavity,
i) in use, a body forming the impeller axis substantially parallel to the cavity axis;
ii) a number of vanes located on the body for urging fluid from the inlet to the outlet during use;
iii) multiple driver magnets;
iv) a second bearing member, wherein the first and second bearing members cooperate to thereby limit movement of the impeller in a direction parallel to the cavity axis. Impeller,
c) coupled to the set of coils and adapted to control the magnetic field generated by the first set of coils, thereby controlling the rotation of the driver about the driver axis A fluid pump including a control device. The fluid pump according to any one of claims 8 to 10, wherein the fluid pump further includes a bearing for controlling the movement of the impeller in a direction perpendicular to the cavity axis. The bearing is
a) the inner surface of the housing;
b) an outer surface, and in use, when a fluid is pumped, a boundary layer is formed between the inner surface portion and the outer surface portion, thereby limiting movement of the impeller in a direction perpendicular to the cavity axis 12. The fluid pump of claim 11, wherein at least a portion of the outer surface includes an impeller having an outer surface having a shape that cooperates with a correspondingly shaped portion of the inner surface. The bearing is
a) a second set of coils for generating a second magnetic field;
b) at least two sensors adapted to detect the position of the impeller within the cavity, wherein the controller controls the third magnetic field according to a signal from the sensor, whereby the cavity The fluid pump of claim 11, wherein the movement of the impeller in a direction perpendicular to the axis is controlled. 14. The fluid pump includes at least one sensor located at a first end of the cavity and at least two sensors located at a second opposing end of the cavity. The fluid pump according to any one of the above. A fluid pump,
a) a housing having an inner surface forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a set of coils coupled to the housing for generating a first magnetic field;
iv) a housing having a set of magnets coupled to the housing to generate an axial control magnetic field;
b) an impeller located within the cavity for biasing fluid from the inlet to the outlet;
i) a body forming an impeller shaft;
ii) in use, a number of driver magnets located in the first magnetic field;
iii) an outer surface, and when in use, fluid is pumped, a boundary layer is formed between the inner surface portion and the outer surface portion, thereby limiting movement of the impeller in a direction perpendicular to the cavity axis. An outer surface that is shaped such that at least a portion of the outer surface cooperates with a correspondingly shaped portion of the inner surface;
iv) an impeller having a number of axial support magnets located in the axial control field and thereby restricting the movement of the impeller in a direction parallel to the cavity axis;
c) a fluid pump including a control device for controlling the magnetic field and thereby rotating the impeller about the impeller axis. a) a housing forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a housing having first and second sets of coils for generating first and second magnetic fields;
b) an impeller located in the cavity,
i) in use, a body forming the impeller axis substantially parallel to the cavity axis;
ii) a number of vanes located on the body for urging fluid from the inlet to the outlet during use;
iii) an impeller having a number of driver magnets located in the first and second magnetic fields during use;
c) a method for pumping fluid with a fluid pump having at least two sensors adapted to detect the position of the impeller within the cavity,
i) controlling the first magnetic field, thereby controlling rotation of the impeller about the impeller axis;
ii) controlling the second magnetic field, thereby controlling the movement of the impeller in a direction perpendicular to the cavity axis. a) a housing forming a cavity having a cavity axis,
i) at least one fluid inlet;
ii) at least one fluid outlet;
iii) a housing having a set of coils for generating a magnetic field;
b) an impeller located in the cavity,
i) in use, a body forming an impeller axis substantially parallel to the cavity axis;
ii) a number of vanes located on the body for urging fluid from the inlet to the outlet during use;
iii) an impeller having a number of driver magnets located within the first magnetic field during use;
c) a method for pumping fluid by a fluid pump having at least two sensors adapted to detect the position of the impeller in the cavity, wherein the method controls the magnetic field, i) the Controlling rotation of the impeller about the impeller axis;
ii) controlling the movement of the impeller in a direction parallel to the cavity axis. 68. A computer program product comprising computer executable code that, when executed on a suitable processing system, causes the processing system to perform the method of claim 66 or 67. An impeller for use with a fluid pump, wherein the impeller is mounted within the pump cavity and is adapted to bias fluid from the first and second inlets to the corresponding first and second outlets;
a) a main body forming an impeller shaft and including first and second main body ends;
b) in use, a set of vanes located on each body end to bias fluid from each inlet to the corresponding outlet;
c) a number of driver magnets located within said first and second magnetic fields during use;
d) In use, when a fluid is pumped, a boundary layer is formed between the inner surface portion and the outer surface portion, thereby limiting the movement of the impeller in a direction perpendicular to the cavity axis. An impeller including an outer surface portion shaped to cooperate with a correspondingly shaped portion of the inner surface. 70. The impeller of claim 69, wherein the impeller forms part of the fluid pump of claim 1. An impeller for use in a fluid pump, mounted in the pump cavity, for biasing fluid from the first and second inlets to the corresponding first and second outlets;
a) a main body forming an impeller shaft and including first and second main body ends;
b) in use, a set of vanes located on each body end to bias fluid from each inlet to the corresponding outlet;
c) a number of driver magnets located within said first and second magnetic fields during use;
d) an impeller including at least a first portion of an axial coupling for limiting movement of the impeller in a direction parallel to the impeller axis. The axial coupling is
a) a second bearing member adapted to cooperate with a first bearing member provided on the housing; and b) a plurality of support magnets for positioning the axial control magnetic field during use. 62. An impeller according to claim 61 comprising at least one of the following. 73. An impeller according to claims 69-72, wherein the size of the blade is selected to control at least one of the fluid pressure and the flow rate at the outlet. The dimensions are
a) the height of the blade,
b) the diameter of the impeller,
c) the length of the blade,
d) the width of the blade,
e) the angle of the inlet and outlet vanes,
f) the shape of the blade,
64. The impeller of claim 63, comprising g) at least one of the number of blades. The impeller is used so that the inlet is aligned parallel to the axis of the body when each inlet is positioned to deliver fluid along the axis of the body in the direction of each body end. 75. Any one of claims 69 to 74, wherein the impeller is located in the cavity of the pump and rotates during use, thereby urging the fluid radially outward in the direction of the outlet. The impeller described in 1. 76. The method of any one of claims 69 to 75, wherein the body includes a generally cylindrical central body portion positioned between the two ends, and the driver magnet is located within the cylindrical central body portion. The impeller described. The impeller can cooperate with the pump cavity to form first and second cavity portions, each cavity portion including a respective inlet, outlet, and body end, wherein the impeller includes 77. An impeller according to any one of claims 69 to 76, adapted to substantially prevent fluid movement between the cavities. 78. Any of claims 69-77, wherein the impeller can be used with a heart pump, and the first and second sets of vanes are adapted to pump blood to assist the left and right ventricles, respectively. The impeller according to item 1.

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