JPH0769202B2 - Ultrasonic fluid meter - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ultrasonic fluid measuring instrument that measures the flow velocity in a pipe using ultrasonic waves and monitors or controls this measured value.

[Prior Art] Conventionally, when measuring the flow velocity or flow rate of a fluid to be measured flowing in a pipe using ultrasonic waves, a probe such as an ultrasonic flowmeter is fixed to the outer wall of the pipe before use. There is. Further, in recent years, during open heart surgery and other operations, development of an artificial heart-lung machine, an auxiliary heart, or an artificial heart device for assisting the heart or cardiopulmonary function externally or temporarily outside the body has been advanced. There is. Then, the artificial heart-lung machine, assist heart, or artificial heart device is also effective in clinical application to patients during actual treatment.

In such clinical applications, especially blood flow measurement,
An important monitoring element, ultrasonic flow meters allow the measurement of flow without direct contact with blood.
It is said to be effective.

On the other hand, according to the "flow rate measuring pipe" disclosed in JP-A-60-181616, a thin film portion is formed on the outer peripheral surface of the inner pipe at a position along a diagonal line of the measuring pipe, and the thin film portion is interposed therebetween. It has been proposed that the flow rate can be detected by an ultrasonic transducer in a sterilized and stable state.

[Problems to be Solved by the Invention] When using the former ultrasonic flowmeter described above, the probe for flow velocity measurement is adhered to the outer wall of the pipe with an adhesive, or the pipe is attached with a band or a special holder. Must be fixed to the outer wall of the, and if the mounting position is wrong, the recovery operation is very troublesome. Further, if the tube is thick, ultrasonic waves are absorbed by the tube wall and attenuated, which may deteriorate the measurement accuracy. In particular, in order to prevent the deterioration of the measurement accuracy due to the attenuation of the ultrasonic wave, the ultrasonic wave output must be increased, which is not preferable because the cost is increased.

Further, according to the "flow rate measuring tube" disclosed in the above-mentioned JP-A-60-181616, an ultrasonic transducer is provided in the measuring tube held in a state of being inserted into the outer peripheral surface of the inner tube. However, the probe provided with the ultrasonic transducer cannot be easily attached to and detached from the tubular body, and the probe must always be used in an integrated state.

Therefore, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to be detachably attached to a tubular body when using a measurement probe detachably provided to the tubular body. An object of the present invention is to provide an ultrasonic fluid measuring instrument that can clearly indicate the mounting position of a tube measurement probe and can further improve the measurement accuracy of flow velocity.

[Means for Solving Problems] In order to solve the above-mentioned problems and achieve the object, an ultrasonic fluid measuring instrument according to the present invention is provided with a tubular body through which a fluid to be measured flows and a tubular body. An ultrasonic fluid measuring instrument comprising a flow velocity measuring probe detachably attached to the tubular body, wherein the tubular body is formed with a recess for positioning the flow velocity measuring probe on the outer peripheral surface of the tubular body, and The measuring probe includes an ultrasonic wave detecting means in which at least a part of the measuring probe is infiltrated into the recess, and an elastic body having a substantially C-shaped cross section for gripping the flow velocity measuring probe with respect to the tubular body. And a grip portion made of.

According to the first embodiment of the ultrasonic fluid measuring instrument of the present invention, the thickness of the portion of the tubular body provided with the recess is sufficiently reduced from the thickness of the other portion of the tubular body. It has a feature.

According to the second embodiment of the ultrasonic fluid measuring instrument of the present invention, the thickness of the portion of the tubular body provided with the recess is 0.
It is characterized by being set to 3 to 0.7 mm.

According to a third embodiment of the ultrasonic fluid measuring instrument according to the present invention, the bottom surface of the recess is formed of a curved surface, and the thickness of the portion of the tubular body provided with the recess has a predetermined value. It is characterized by being kept constant.

According to a fourth embodiment of the ultrasonic fluid measuring instrument of the present invention, the bottom surface of the recess is composed of a flat surface, and the thickness of the central portion of the tube portion provided with the recess is the smallest. It is characterized by

[Operation] In the ultrasonic fluid measurement device configured as described above,
When the probe is attached to the outer wall of the tube, the recess formed in the probe may be targeted, and the operator does not have to make a mistake in the attachment position. Also, by providing this recess, the thickness of the portion of the tube body in which this recess is provided will be reduced. Therefore, the ultrasonic wave passing through the portion having the reduced thickness is less attenuated here, and the measurement accuracy is improved.

[Embodiment] Hereinafter, the configuration of an embodiment in which the ultrasonic fluid meter according to the present invention is applied to a tube used in an ultrasonic flow meter will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the ultrasonic flowmeter 10 is detachably attached to the outer wall of a tube 12 through which blood as a fluid to be measured flows while the attached state is maintained, and blood flowing in the tube 12 is retained. Probe 14 for detecting the flow rate of the ultrasonic wave through ultrasonic waves, and electrically connected to this probe 14 through a cable 16, and calculates the flow rate of blood flowing in the tube 12 based on the flow rate detected by the probe 14. And a computing device 18.

In this embodiment, the probe 14 is used to measure the blood flow rate in the blood circuit for the assisting heart, and the blood removing canister for sending blood from the patient to the pump 20 for the assisting heart, It is used as the tube 12 through which blood as the fluid to be measured described above flows. A pump 20 for the auxiliary heart is provided with a blood-sending cannula 22 for returning the blood energized here to the patient.

The probe 14 described above includes a probe body 24 detachably attached to the outer wall of the tube 12 through which blood as a fluid to be measured flows, as shown by different cross sections in FIGS. 2A and 2B. In this probe body 24, an ultrasonic transmitter 26a that is fixed in the base 24a of the probe body 24 and outputs ultrasonic waves toward the blood flowing in the tube 12,
An ultrasonic receiver 26b that receives ultrasonic waves reflected in flowing blood and detects data relating to the flow velocity is provided with their axes intersecting each other. Cable mentioned above
One end of 16 is the ultrasonic transmitter 26a and the ultrasonic receiver 26b.
Are connected to and respectively.

The ultrasonic transmitter 26a and the ultrasonic receiver 26b constitute a detection mechanism 26 that detects data regarding the flow velocity. The detection mechanism 26 is arranged on the mount 24b made of acrylic resin in the base 24a.

Further, as is clear from FIG. 2B, the portion of the base 24a facing the outer wall of the tube 12 is formed so as to project toward the portion of the tube 12 to be attached in a planar rectangular shape. Then, on the surface of the projecting portion of the base 24a, a recess 24c for accommodating the mounting base 24b with the detection mechanism 26 attached thereto is formed.

Further, as is clear from FIG. 2A, the probe main body 24 is
In a state of being integrally formed with the base 24a, the outer wall of the pipe 12 is grasped so as to be sandwiched from both sides, and the base 24a is arranged at intervals so as to prevent the base 24a from falling off from the pipe 12. It is provided with a pair of gripping pieces 24d. The probe main body 24 including these gripping pieces 24d is made of urethane rubber as an elastic body.

In addition, the distance between the tips of the pair of gripping pieces 24d is
The diameter is set smaller than the diameter of the tube 12, and the interval in the middle portion is set to be substantially the same as the diameter of the tube 12. In this way, when the probe 14 is mounted, this mounted state is maintained, and at the time of mounting, since the pair of gripping pieces 24d is formed of an elastic body, these The tip is configured to be open and well grasped by the outer wall of tube 12.

Here, in this embodiment, the inner surfaces of the base 24a and the pair of gripping pieces 24d are set to be continuous and are formed in a shape corresponding to the outer wall of the tube 12. That is, the probe main body 24 is formed in a substantially C shape as a whole. Thus, in the state where the probe 14 is attached to the outer wall of the tube 12, as shown in FIG. 2A, the inner surfaces of the base 24a and the pair of gripping pieces 24d are in close contact with the outer peripheral surface of the tube 12, The frictional engagement with each other ensures that the mounted state is maintained.

On the other hand, the blood removal cannula as the tube 12 to which such a probe 14 is attached is made of a soft vinyl chloride resin, and the attached portion of the tube 12 has a portion as shown in FIGS. 1 and 3. A recess 12a into which the protruding portion of the probe 14 is fitted is formed. This mounted portion is set on the side of the tube 12 that is close to the pump 20. This recess 12a is
With the function to clearly indicate the mounting position of the probe 14, the recess 12
The thickness of the tube 12 is reduced by the amount of forming a, and the tube 12 is made to have the minimum thickness t.
It will exert the function of reducing the attenuation of ultrasonic waves transmitted from a.

Here, this minimum thickness t is set from the viewpoint of the accuracy of forming the recess 12a and the attenuation rate of the ultrasonic wave, and in this embodiment, 0.5 ± 0.2 mm, that is, This thickness t is set within a range of 0.7 mm at maximum and 0.3 mm at minimum.

The thickness t is constant in all parts as shown in FIG. In other words, the bottom surface of the recess 12a is
The tube 12 is formed of a curved surface along the inner peripheral surface, and the lower surface of the protrusion formed on the base 24a of the probe body 24 is also formed of a curved surface along the inner peripheral surface of the tube 12.

An operation of using the probe 14 for measuring the flow velocity in the ultrasonic flowmeter 10 configured as above will be described.

In the open-heart surgery, in order to control the driving state of the pump 20 for the auxiliary heart when the auxiliary heart is used,
The flow rate of the blood removed is measured by the ultrasonic flow meter 10. In this measurement, first, on the bottom surface of the recess 12a of the tube 12, in order to prevent air and bubbles from entering between the probe body 14 and the probe body 14 and increasing the attenuation of the ultrasonic wave, Liquid is applied. After the application of this jelly, the probe 14 for measuring the flow velocity is fitted into the tube to which blood as the fluid to be measured flows, that is, the portion to be attached of the blood removal cannula 12. Here, since the recess 12a is formed in the portion of the tube 12 at the mounted position, the operator
It is possible to surely and easily recognize the mounted position without making a mistake. Also, the mounting operation is simply
It suffices to press the tube 12 between the tip portions of the pair of gripping pieces 24d of the probe main body 24 having a C-shaped cross section, which are separated from each other. That is, since the pair of gripping pieces 24d is formed of an elastic body, the distance between the tip portions of the gripping pieces 24d is
Although the diameter is set to be smaller than the diameter, the gripping pieces 24d open outward with the pressing operation. After that, the tip portion passes through the diameter portion of the tube 12 to be closed again by the elastic return force of the gripping piece 24d, and the second A
It will be in the state shown in the figure. In this way, the probe 14 is securely gripped by the outer wall of the tube 12, and this gripped state is well maintained.

After that, by starting the operation of the arithmetic unit 18, ultrasonic waves from the ultrasonic transmitter 26a of the detection mechanism 26, for example, 5MHz.
Is transmitted as a continuous wave of. The ultrasonic waves thus transmitted are reflected by the blood flowing in the tube 12, and the reflected ultrasonic waves are received by the ultrasonic receiver 26b with different frequencies due to the Doppler effect. .

The data on the flow velocity at the place received by the ultrasonic receiver 26b is sent to the arithmetic unit 18 via the cable 16, where the arithmetic unit 18 performs information processing and
The flow rate of blood flowing inside is calculated.

In this way, after the blood flow rate is measured and the open-heart surgery is completed, the probe 14 is removed from the tube 12, and the series of measurement operations is completed. After this, the recess 12a formed in the tube 12
, The thickness t of this portion is set to be extremely thin. Therefore, in order to protect this, the dummy probe 28
As shown in the figure, the pipe 12 is attached to the attached portion. As described in detail above, according to this embodiment, since the probe 14 for measuring the flow velocity is formed of the elastic body in a substantially C-shaped cross section,
The mounted state of the probe 14 is maintained well, the mounting operation of the probe 14 is extremely simplified, and the operation time is shortened. In this way, even if you need to measure the flow urgently,
By using this probe 14, it is possible to surely deal with it.

Further, according to this embodiment, since the recess 12a is formed in the mounting portion of the tube 12 to which the probe 14 is mounted, the operator does not make a mistake in the mounting position of the probe 14. Further, by forming the recess 12a in the tube 12, the thickness of the tube 12 of this mounted portion is set to be extremely thin, and accordingly, the attenuation of the ultrasonic waves used for measurement is satisfactorily suppressed and the measurement is performed. The accuracy will be improved.

Further, since the cannula is generally tapered, if the probe 14 is not attached to the portion of the cannula corresponding to the inner diameter of the probe 14, the probe 14 may fall out due to looseness, or the measurement accuracy may deteriorate. According to this embodiment, since the mounting position is clearly indicated by the recess 12a, such a fear can be completely eliminated.

It goes without saying that the present invention is not limited to the configuration of the above-described embodiment and can be variously modified without departing from the scope of the present invention.

For example, in the above-described embodiment, the recess 12a formed in the tube 12 is formed so that the thickness of the part of the tube 12 in which the recess 12a is provided is constant as shown in FIG. Although described, the present invention is not limited to such a configuration, and as shown as a modified example in FIG. 5, the bottom surface of the recess 12b is formed of a flat surface, and the pipe is set by providing the recess 12b. 12
The minimum thickness may be defined as the thickness t as described above. By setting the recess 12b in this manner, the effect of simplifying the operation of forming the recess 12b is achieved.

Further, in the above-described embodiment, the tube 12 in which the recess 12a is formed has been described as being composed of the blood removal cannula, but the structure is not limited to such a structure, and is not limited to FIG. As shown as a modified example of the above, the blood supply cannula 22 may be provided with a recess 22a. The point is that this recess is set anywhere where the fluid to be measured flows.

[Effects of the Invention] As described above, according to the ultrasonic fluid measuring instrument of the present invention, when the measurement probe detachably attached to the tubular body is used, the mounting position of the measurement probe is clearly specified. Thus, it is possible to provide an ultrasonic fluid measuring instrument that can be reliably fixed and can further improve the measurement accuracy of the flow velocity.

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing the structure of a flow velocity measuring probe to which an embodiment of an ultrasonic fluid measuring instrument according to the present invention is applied and an ultrasonic flow meter using the same; FIGS. 2A and 2B. FIG. 4 is a cross-sectional view showing how the probe is attached to the tube by cutting it with different cutting planes; FIG. 3 is a cross-sectional view of the tube showing the shape of the recess; FIG. 4 is a perspective view showing how the dummy probe is attached. FIG. 5 is a sectional view showing a modified example of the recess; and FIG. 6 is a front view showing another modified example of the setting position of the recess. In the figure, 10 ... Ultrasonic flowmeter, 12 ... Tube (blood removal cannula), 12a ... Recess, 14 ... Flow velocity measurement probe, 16 ...
… Cable, 18 …… Computing device, 20 …… Pump, 22 …… Blood supply canister, 22a …… Recess, 24 …… Probe body, 24a
...... Base, 24b ...... Mounting base, 24c ...... Recess, 24d ...... Grip piece, 26 ...... Detection mechanism, 26a ...... Ultrasonic transmitter, 26b ......
Ultrasonic receiver, 28 ... a dummy probe.

Claims (5)

[Claims] 1. An ultrasonic fluid measuring instrument comprising a tubular body through which a fluid to be measured flows, and a flow velocity measuring probe detachably attached to the tubular body, wherein the tubular body is A concave portion for positioning and fixing the flow velocity measuring probe is formed on the outer peripheral surface of the tubular body, and the flow velocity measuring probe has an ultrasonic detecting means in which at least a part of the probe is embedded in the concave portion, An ultrasonic fluid measuring instrument, comprising: a grip portion made of an elastic body having a substantially C-shaped cross section for gripping the flow velocity measuring probe with respect to the tubular body. 2. The thickness according to claim 1, wherein the thickness of the portion of the tubular body provided with the recess is sufficiently reduced from the thickness of other portions of the tubular body. Ultrasonic fluid meter. 3. The ultrasonic fluid measuring instrument according to claim 2, wherein the thickness of the portion of the tubular body provided with the recess is set to 0.3 to 0.7 mm. . 4. The bottom surface of the recess is composed of a curved surface, and the thickness of the portion of the tubular body provided with the recess is kept constant at a predetermined value. The ultrasonic fluid measuring instrument according to the second item of the range. 5. The bottom surface of the recess is formed of a flat surface, and the cross-sectional shape is substantially D-shaped so that the thickness of the portion of the tubular body provided with the recess is the smallest in the central portion. The ultrasonic fluid measuring instrument according to claim 2 or 3, wherein the ultrasonic fluid measuring instrument is formed.