CN110462211A - Double Disc and Double Cylinder Pumps - Google Patents

Abstract

The invention relates to a pump (1) comprising two pumping assemblies distributed symmetrically with respect to a plane perpendicular to an axis of a drive shaft (12), each pumping assembly comprising a cylinder (4, 5), a disc (2, 3), suction pipes (8, 9) and delivery pipes (10, 11), the discs (2, 3) of each assembly are interconnected at the plane of symmetry.

Description

Double Disc and Double Cylinder Pumps

The present invention relates to the field of pumps, in particular for high pressure and high output pumping, in particular for drilling operations in the range of several hundred meters to several kilometers.

In the field of hydrocarbon production, it is now found that the wellbore needs to be drawn deeper and deeper, which means working at higher and higher injection pressures. Therefore, oil companies and service industries in the oil industry require pumps at very high pressures (eg, for jetting drilling mud) to reach the required depths. These pumps must also be reliable, economical, flexible and compact in order to meet the increasingly stringent requirements of the energy sector.

In general, pumps driven by crankshafts are most prevalent in all industry sectors: equipment, oil, gas and agro-industry, automotive industry, construction (heating, wells, air conditioning, water pumps, etc.), and more specifically for processing Water and waste (water networks and drainage systems). To date, pumps of this type have included a limited number of pistons (approximately 5), which are unexpectedly subjected to high stresses and sudden changes in pressure that can occur on the delivery side because of the size constraints of the crankshaft. As such, these pumps are limited in their power, their pressure/output pairing (limited by the "water hammer" created by the sinusoidal pressure of the crankshaft), their weight, their efficiency, and their longevity. Furthermore, they do not offer the possibility of having a variable displacement and therefore lack flexibility of use.

Another positive displacement pump technology is the barrel piston pump, also known as a wobble-plate pump or swashplate pump, which involves a disk and a barrel. For this type of pump, the pistons are distributed in a circle, unlike crankshaft pumps where the pistons are aligned. Pumps designed with discs and cylinders operate using a wobble disc system or wobble disc system in which the disc actuates the individual pistons one after the other. When one piston is in the suction phase, the opposite piston is in delivery mode, providing constant flow upstream and downstream of the pump. The distribution of the positions of the pistons guided by the cylinders provides a gradual distribution of the load as the shaft is rotated by the motor.

Primarily used for low pressure and low output pumping (mainly for pumping hydraulic oil), this type of pump offers many advantages:

- Excellent weight/power ratio

- very good quality / price ratio

- Favorable mechanical and volumetric efficiency

- Possibility to have variable displacement by adjusting the angle of the disc.

Generally speaking, there are three main designs of barrel piston pumps:

- Fixed cylinder pump (Fig. 1): In this configuration of pump 1, where the cylinder is fixed, the swash plate/oscillating plate 2 rotates (driven by the shaft 5) to produce the movement of the piston 3 in its bushing 4 . The connection between the piston 3 and the disc 2 is then provided by a ball joint sliding pad that rubs against the disc 2 . The advantage here is that the rotating parts have a very low inertia.

- Rotary Cylinder Swing Disc Pump ( FIG. 2 ): Inside the pump 1 , the disc 2 is fixed and the cylinder 6 carrying the piston 3 rotates, causing the movement of the piston 3 in its bushing 4 . The piston 3-disc 2 connection is provided in the same way as in the first configuration. The advantage of this design is that it is easy to make the angle of the oscillating plate adjustable, and therefore variable displacement is possible. Conversely, as the cylinder and all pistons are rotated, the inertia of each rotating component increases significantly.

- Oscillating disc pump: In this design the cylinder is fixed and there are two discs; the inclined first disc rotates and only transmits the oscillating motion to the second disc. Thus, the piston can be connected to the second wobble disc without the need for friction elements, for example using a connecting rod connected to the piston and disc by means of a ball joint connection. Since there are no friction elements (and occasionally some are found in geothermal applications), this is the only design suitable for high pressure pumping. It also provides excellent mechanical efficiency.

In the case of such a barrel piston pump, the number and diameter of the pistons and the angle of the disc determine the desired output of the pump. In fact, when the pump is running, the pistons are alternately at high pressure and then at atmospheric pressure, so that the cylinder/piston assembly exerts a load on the disc, the module of which is spatially non-uniform. Specifically, on the suction pipe (atmospheric pressure), the load is relatively low, and on the delivery pipe, the load is the largest.

In addition, when using barrel piston pumps in very deep drilling combined with high pressure and high flow (high delivery) fields, whether they have a rotating cylinder, wobble or oscillating disk, the force exerted by a large number of pistons can cause damage to the disk and the Considerable loads are placed on the mechanical connections between the components, which in extreme conditions can lead to deformation of the disc or breakage of the connections. Furthermore, the connection (section) between the piston and the disc, eg provided by a ball joint pad, needs to be designed with minimal friction.

This imbalance in the load applied to the disks can create large forces on the disks and on the mechanical connections of the system, which results in heavier and larger components that consume more energy for the pump. Also, if the applied load is too great, the connection (section) between the piston and the disc, eg using a ball joint pad, may not be designed.

Also known is the patent CN 103696920, which describes a hydraulic pump comprising two disc and two cylinder assemblies, each rigid assembly having a set of pistons. In this design, the discs are positioned at opposite ends of the pump and the cylinder is in the middle, so the pump has only one suction and one delivery. However, such pumps require each disc to be sized independently, which can be difficult in high pressure and high output applications. In addition, this configuration of the various pump elements does not allow for common adjustment of the angle (tilt) of the disc.

To overcome these drawbacks, the present invention relates to a dual-barrel dual-disc pump with dual suction/delivery sections, the elements of each barrel-disc-suction-delivery section assembly being distributed along the drive shaft in order to reduce stress on discs and different mechanical connections, thereby reducing the risk of cracking.

Device according to the invention

The present invention relates to a barrel piston pump comprising at least one drive shaft, a first pumping assembly and a second pumping assembly, each pumping assembly being formed from elements comprising at least one disc, a cylinder, a suction pipe and a delivery pipe , the cylinder includes at least two compression chambers distributed in the circumferential direction, and at least two pistons move in translation respectively in the compression chambers of the cylinder of each of the components, and the two components of the two components The disk of each assembly is inclined at an angle with respect to the axis of rotation of the drive shaft that produces relative rotation between the disk and the cylinder of each of the two assemblies sports.

According to the invention, the elements of the second assembly are distributed symmetrically with respect to the elements of the first assembly with respect to a plane perpendicular to the axis of rotation of the drive shaft, and the disks of the two assemblies are in The symmetry planes are connected to each other.

Advantageously, the suction pipe and the delivery pipe of one and the same assembly can be positioned symmetrically with respect to the axis of the drive shaft.

According to an embodiment of the invention, the discs of the two assemblies may be formed as a single unit.

According to one embodiment option, the discs of the two assemblies may be connected to each other by connecting means passing through the symmetry plane.

According to one embodiment, the connection means may comprise a pivot connection positioned at a point substantially at the perimeter of the two discs.

According to an alternative form of embodiment of the present invention, the relative rotational movement may be rotational movement of the disk of each of the assemblies.

According to another alternative form of embodiment of the present invention, each of the assemblies may further comprise a wobble plate, the wobble plate of each of the assemblies pivotally connected to the wobble plate of the same assembly Spin the disc.

According to another embodiment option of the present invention, the relative rotational movement may be a rotational movement of the cylinder of each of the assemblies.

According to one embodiment, the absolute value of the angle of inclination of the disc of each of the assemblies relative to the axis of the drive shaft may be comprised between 70° and 90°.

Advantageously, the pump may comprise means for controlling the angular inclination of the disc of each of the assemblies relative to the axis of the drive shaft.

Furthermore, the present invention relates to the use of said barrel piston pump for drilling operations, in particular for injecting drilling mud into a drilled wellbore.

Description of drawings

Other features and advantages of the device according to the invention will become apparent when reading the following description of non-limiting exemplary embodiments with reference to the following figures.

Figure 1, already described, shows a fixed-cylinder oscillating pump according to the prior art.

Figure 2, which has already been described, shows a rotary cylinder oscillating disc pump according to the prior art.

Figure 3 shows a pump according to a first embodiment of the invention.

Figure 4 shows a pump according to a second embodiment of the invention.

Detailed ways

The invention relates to a barrel type piston pump. Cartridge piston pumps are used to pump fluids (eg, water, oil, gas, drilling mud, etc.) by means of the linear displacement of multiple pistons. This type of pump has the advantage of being compact, having favorable mechanical and volumetric efficiencies, and having an excellent weight/power ratio. The barrel piston pump according to the present invention may be a stationary cylinder pump, a rotary cylinder pump or a swing type pump.

A barrel piston pump according to the present invention generally includes a housing, and within the housing includes:

- drive shaft: this drive shaft is driven in rotation relative to the housing by an external energy source, in particular driving a machine (for example a heat engine or an electric motor), in particular by means of a transmission (for example a gearbox);

- a first set of pumping elements, comprising at least one disc, a cylinder (referred to as a cylinder), suction and delivery pipes, and a second set of pumping elements, comprising at least the same elements as the first pumping assembly, these sets/ The elements of each group/assembly in the assembly are distributed along the drive shaft. In the conventional manner, the cylinder comprises at least two compression chambers (also called bushings) distributed circumferentially (in other words, the compression chambers are arranged in a circle), and at least two pistons move in translation in the compression chambers, respectively, the pistons The translational movement within the compression chamber enables the pumping of the fluid. The tray of each assembly may be in a substantially tray-shaped form. However, the disc can have any shape. Only the compression chambers (and pistons) are arranged on the circumference (in a circular arrangement). Furthermore, in the conventional manner, the fluid to be pumped through the suction line of one of the assemblies enters the compression chamber of that assembly, is compressed and is then delivered from the pump through the delivery line of that assembly.

Furthermore, according to the present invention:

- the disk of each of the two assemblies is inclined at an angle relative to the axis of rotation of the drive shaft. The angular inclination of the disc affects the stroke of the piston in the compression chamber, which determines the displacement of the pump;

- the drive shaft induces a relative rotational movement between the cylinder and the disk of each of the two assemblies. Therefore, according to the present invention, the drive shaft can also rotate the disk as well as the cylinder

- The distribution of the elements of the second assembly is symmetrical with respect to the distribution of the elements of the first assembly with respect to a plane perpendicular to the axis of rotation of the drive shaft, at which plane of symmetry the disks of the two assemblies are interconnected. Thus, the barrel piston pump according to the present invention comprises, from one end to the other end, a first suction and delivery pipe, a first cylinder, a first disk, a second disk, a second cylinder and a second suction and delivery pipe, all of which are driven shaft passes through.

Thus, according to the invention, the discs of each pumping assembly are inclined at the same angle in absolute value and face each other. The force applied to each disc by the translational motion of the piston in each compression chamber of each cylinder has the same norm but opposite directions. Since the disks of the two assemblies are connected to each other, this configuration makes it possible to reduce the axial loads experienced by the disks and by the disk-piston mechanical connection.

Advantageously, the suction and delivery pipes of each pumping assembly can be positioned symmetrically with respect to the axis of the drive shaft, or in other words, the suction and delivery pipes of the same assembly face each other with respect to (across) the drive shaft. Therefore, the distribution of the axial force on the disc can be more easily balanced.

According to a first alternative form of embodiment of the invention, the drive shaft rotates the disk of each of the two assemblies, the rotational movement being considered relative to the casing of the pump. Thus, this first alternative describes a pump in which the cylinder is fixed. According to this alternative, the rotating disks of a given assembly are tilted relative to the drive shaft at the same inclination angle as the rotating disks of the other assembly, each disk also being rotated by the drive shaft.

According to a second alternative form of embodiment of the invention, the drive shaft rotates the cylinder or cylinder of each of the two pumping assemblies, the rotational movement being considered relative to the casing of the pump. Thus, this second alternative describes a rotary cylinder oscillating disc pump. In this alternative, the discs of each pumping assembly are fixed and tilted at the same absolute tilt angle. For this alternative, the rotary cylinder of each pumping assembly causes translational movement of the pistons in their respective compression chambers via the connection between the pistons and the disks of their respective pumping assemblies.

According to a third alternative form of embodiment of the invention, each of the two pumping assemblies comprises at least two discs parallel to each other (and thus both inclined at the same angle at the same time): rotated by the drive shaft and a swinging plate oscillated by the rotating plate, the swinging plate is pivotally connected relative to the rotating plate about the axis of the rotating plate. Therefore, according to this alternative, the rotating disk only transmits the oscillating motion to the oscillating disk and not the rotational motion. According to this design, the piston of each compression chamber of a given pumping assembly is driven by the wobble plate of that assembly, for example by means of a connecting rod (the connecting rod uses a ball joint connection to connect the wobble plate and the piston, thereby converting the wobble motion into The translational movement of the piston), and the translation of the piston within the compression chamber enables the pumping of the fluid. According to this alternative form of the invention, the rotating disk can be driven by the drive shaft by means of a pinned ball joint (finger ball joint), the position of which determines the two disks (rotating disk and oscillating disk) relative to the drive shaft angle of inclination. It will be thought that a ball joint with pins is a connection between two elements (in this case a drive shaft and a rotating disc) with four degrees of connection (freedom) and two relative motions (freedom) degrees; only two relative rotations are possible, three translational motions and a final rotational connection. Usually, it is a ball joint with pins (spikes, fingers) that prevent one of them from rotating.

According to one embodiment of the invention applicable to any of the above-mentioned alternatives, the trays of the two components are formed as a single unit. This makes it possible to reduce the fragility of the contact between the two discs and thus to increase the reliability of the pump according to the invention.

According to one embodiment of the invention applicable to any of the above alternative forms, the discs of the two assemblies are connected to each other by connecting means. Advantageously, the connection means connecting the disks of the two assemblies comprises a pivoting connection positioned at a point substantially at the perimeter of the two disks. Traditionally, pivot connections are formed by sliding or rolling bearings that facilitate the relative movement of the elements. The pivotal connection allows adjustment of the inclination of the discs of each pumping assembly. Preferably, the connection means connecting the discs of the two assemblies comprises in addition to the pivotal connection at least one spacer element of variable length positioned so as to reinforce the two elements joined together by the pivotal connection. Assemblies formed by tilted discs.

Advantageously, the angular inclination of one or more discs of each assembly is continuously adjustable by controlling the inclination of the discs, thereby enabling variable displacement. Specifically, the angular inclination of the disc affects the stroke of the piston. Therefore, the pump according to this alternative form offers good flexibility due to the continuous variation of the individual displacements. Furthermore, this fourth alternative form of pump according to an embodiment allows for a stepwise operation of the pump: for example, at start-up the angle of inclination can be small and then can be increased depending on the desired conditions (fluid throughput and pressure) . This makes it possible to improve the reliability of the pump. According to an exemplary embodiment, the means for controlling the inclination of the disc interact with the connecting means connecting the discs of the two pumping assemblies. According to an embodiment option of the present invention, wherein the connecting means comprise a pivoting link and a variable height spacer element as described above, means for controlling the inclination of the disc and means for adjusting the height of the spacer elements Coordinate to increase or decrease the spacing between discs. According to an embodiment option of the invention, the means for controlling the inclination of the disc are provided by a worm.

According to one embodiment of the present invention, the pump according to the present invention may comprise a plurality of pistons in each cylinder, the number of which is between three and fifteen, preferably between five and eleven. Thus, a large number of pistons provide continuous flow upstream and downstream of the pump.

According to one embodiment of the invention, which can be applied to any of the above-mentioned alternatives, the disk(s) of each pumping element assembly (rotating disks in the case of the first alternative, rotating disks in the second alternative) In the case of a fixed wobble disk, or in the case of a third alternative, a rotating disk and a wobble disk) the angle of inclination is comprised between 70° and 90° in absolute value with respect to the axis of the drive shaft. In other words, one or more disks in one assembly are inclined between 0° and 20° relative to the plane of symmetry of the first and second pumping assemblies, while one or more disks in the other assembly are inclined relative to the plane of symmetry of the first and second pumping assemblies. This same plane of symmetry is inclined between -20° and 0.

Figure 3 shows, by way of non-limiting illustration, a section through the axis of rotation of the drive shaft of the cylinder/disc swing pump according to one embodiment of the invention. The pump 1 according to the embodiment shown is a rotary cylinder swing pump. The pump includes a drive shaft 12 mounted for rotation in a housing (not shown). Rotation of the drive shaft 12 is accomplished by external sources, not shown, such as an electric motor and a gearbox. The pump 1 comprises two pumping assemblies distributed symmetrically with respect to each other with respect to a plane of symmetry perpendicular to the axis of rotation of the shaft. The first assembly (or the second assembly) includes a corresponding fixed disk 2 (or 3), a rotating cylinder (or cylinder block) 4 (or 5), a suction pipe 8 (or 9) and a delivery pipe 10 (or 11). In this figure two pistons 6, 7 are shown for each cylinder, these pistons being arranged in their respective compression chambers and connected to their respective discs by means of ball joint slides. The drive shaft 12 drives the cylinders 4, 5 of each pumping assembly. The disks of each pumping assembly are inclined at the same inclination angle in absolute value with respect to a plane perpendicular to the axis of rotation of the drive shaft. According to this embodiment of the invention, the fixed discs 2, 3 of each set of pumping elements are interconnected by pivotal connections 13 and via spacer elements 14, the length of which may be variable. It is therefore clear that the axial loads on the disks and on the disk-piston mechanical connection are reduced, since the disks face each other directly and experience the same but oppositely directed stresses.

Figure 4 shows an alternative to the pump shown in Figure 3 . In particular, the pump in this non-limiting exemplary embodiment of the pump according to the invention additionally comprises means for controlling the angular inclination of the disc 15 of each pumping assembly in the form of a worm that controls the variable length spacer elements form.

The invention also relates to the use of the pump according to the invention for drilling operations, in particular for injecting drilling mud into a drilled wellbore. In particular, since the pump according to the invention makes it possible to balance the distribution of the axial load, the pump according to the invention can be dimensioned to be able to withstand high pressures and high delivery outputs. In particular, this improvement in the axial load distribution makes it possible to increase the number of pistons to achieve the desired output, and with smaller radial dimensions (larger number of pistons and smaller diameter). For example, a pump according to the invention can be dimensioned to operate at pressures of the order of up to 1500 bar (bar), ie 150 MPa. Furthermore, the pump according to the present invention can be sized to operate at a delivery output (flow rate) varying in the range of 30 to 600 m ³ /h.

Claims (11)

1. A barrel piston pump (1) comprising at least one drive shaft (12), a first pumping assembly and a second pumping assembly, each pumping assembly consisting of at least one disc (2, 3), a cylinder The elements of the body (4, 5), the suction pipe (8, 9) and the delivery pipe (10, 11) are formed, said cylinder (4, 5) comprising at least two compression chambers distributed circumferentially, at least two pistons (6, 7) respectively move in translation within the compression chambers of the cylinders (4, 5) of each of the two assemblies, the discs (2, 3 of each of the two assemblies) ) is inclined at an angle relative to the axis of rotation of the drive shaft (12) in the discs (2, 3) of each of the two assemblies and the A relative rotational movement occurs between the cylinders (4, 5), characterized in that the element of the second assembly is relative to the first assembly with respect to a plane perpendicular to the axis of rotation of the drive shaft (12). The elements are distributed symmetrically and the discs (2, 3) of the two assemblies are connected to each other at the symmetry plane. 2. The pump according to claim 1, characterized in that the suction pipes (8, 9) and the delivery pipes (10, 11) of the same assembly are relative to all positions of the drive shaft (12) The axis is symmetrically positioned. 3. Pump according to one of the preceding claims, characterized in that the pump (1) comprises control means (15) for controlling the said components in each of said assemblies The angle of the discs (2, 3) relative to the axis of the drive shaft (12) is inclined. 4. Pump according to one of the claims 1 or 2, characterized in that the discs (2, 3) of the two assemblies are formed as a single unit. 5. Pump according to one of the claims 1 to 3, characterized in that the discs (2, 3) of the two assemblies are connected by connecting means (13, 14) passing through the symmetry plane to each other. 6. Pump according to claim 5, characterised in that the connecting means (13, 14) comprise a pivoting connection (13) positioned substantially between the two discs (13). 2, 3) at the point at the perimeter. 7. Pump according to one of the preceding claims, characterized in that said relative rotational movement is a rotational movement of said discs (2, 3) of each said assembly. 8. The pump of claim 7, wherein each said assembly additionally comprises a wobble plate, said wobble plate of each said assembly being pivotally connected to said rotating plate ( 2, 3). 9. Pump according to one of the claims 1 to 6, characterized in that the relative rotational movement is the rotational movement of the cylinders (4, 5) of each of the assemblies. 10. Pump according to one of the preceding claims, characterized in that the absolute value of the angle of inclination of the discs (2, 3) of each of the assemblies with respect to the axis of the drive shaft (12) Values are included between 70° and 90°. 11. Use of a barrel piston pump according to one of the preceding claims for drilling operations, in particular for injecting drilling mud into a drilled wellbore.