FR3072735A1 - ROTARY BARREL PUMP WITH DOUBLE TRAYS - Google Patents

Abstract

The present invention relates to a rotary barrel pump (6), which comprises two plates: a movable plate (2) also driven by the drive shaft (5), and a variable inclination plate (7), the two plates (2, 7) being pivotally connected to each other.

Description

The present invention relates to the field of pumps, in particular for high pressure pumping, in particular for drilling operations.

Today, crankshaft pumps are the most common in all industry sectors: capital goods, oil, gas and food industries, automotive, construction (heating, wells, air conditioning, water pumps, etc.) and more specifically for water and waste treatment (water and sanitation network). However, they are still built on concepts dating from the 1930s, and are the subject of very few research and development studies to improve their performance, reduce their cost, minimize maintenance costs or decrease their environmental footprint. These pumps have limits in terms of power, pressure / flow couple (that is to say limits which result in phenomena related to "water hammer" generated by the sinusoidal response of the pressure produced by the crankshaft), weight, efficiency and service life. In addition, they do not allow to have a variable displacement and therefore lack flexibility of use.

In addition, in the field of hydrocarbon production, it is currently observed that the boreholes must reach increasingly deeper depths, which implies working with ever higher injection pressures. Oil companies therefore need very high pressure pumps to reach the depths required for the injection, for example, of drilling muds. They must also be reliable, economical, flexible and compact, in order to meet the increasingly demanding demands of the energy sector.

Another positive displacement pump technology is the barrel pump. Primarily intended for pumping at lower pressure and flow (they are mainly used in the pumping of hydraulic oils), they offer many advantages:

• Excellent weight / power ratio • Very good value for money • Interesting mechanical and volumetric efficiency • Possibility of variable displacement by adjusting the inclination of the platform

Pumps designed with a barrel operate using a turntable system which actuates the different pistons one after the other. When a piston is in the intake phase, the opposite piston is in discharge mode, which provides a constant flow upstream and downstream of the pump. The distribution of the positions of the pistons with a guide by the barrel ensures a progressive distribution of the forces during the rotation of the shaft driven by the motor.

There are three main barrel pump architectures:

• Fixed barrel pumps (Figure 1): in this pump 1 configuration, where the barrel is fixed, it is the inclined plate 2 which rotates (driven by the shaft 5) in order to generate the movement of the pistons 3 in their liners 4 (compression chamber). The connection between the pistons 3 and the plate 2 is then ensured by swivel shoes which rub on the plate 2. The advantage here is to have a very low inertia of the rotating parts. However, this configuration makes it difficult to install variable displacement. In addition, in the case of high pressures and flow rates, the friction forces between the plate and the pads are not negligible, and make the production of the pump complex or even impossible.

• Barrel pumps with swash plate: the barrel is fixed in this architecture and there are two plates, a first inclined plate is in rotation and transfers to the second plate only the oscillation movement. Thus, the pistons can be linked to the second swash plate without the need for friction elements, for example with a connecting rod linked to the piston and to the plate by ball joints. This architecture is suitable for high pressure pumping due to the absence of friction elements (we find some of them on the geothermal market). It also offers excellent mechanical performance. This configuration makes it possible to produce a variable displacement, it nevertheless remains difficult to integrate and to design.

• Rotary barrel pumps (Figure 2): within pump 1, the plate 2 is fixed and the barrel 6 carrying the pistons 3 is in rotation, thus ensuring the movement of the pistons 3 in their liners 4 (compression chamber). The piston 3 - plate 2 connection is provided in the same way as for the first configuration. The advantage of this architecture is that one can easily make the plate adjustable in inclination and thus have the possibility of variable displacement. On the other hand, the inertia of the rotating parts increases significantly since the barrel and the set of pistons are rotated. In addition, for this configuration, there is significant friction between the plate and the connecting rods linked to the pistons. These frictions generate losses in terms of performance.

To overcome these drawbacks, the present invention relates to a rotary barrel pump, which comprises two plates: a movable plate also driven by the drive shaft, and a variable inclination plate, the two plates being in pivot connection one compared to each other. Thus, the drive of the movable plate by the drive shaft allows contact between two rotating parts: the connecting rods and the movable plate, which makes it possible to limit the losses by friction between these parts. The variable tilt allows variable displacement of the pump.

The device according to the invention

The present invention relates to a barrel pump comprising a casing, and comprising within said casing:

- a drive shaft,

a cylinder block comprising at least two compression chambers distributed circumferentially, said cylinder block being driven by said drive shaft,

- a mobile platform,

- At least two pistons in translation respectively in said compression chambers of said cylinder block, said pistons being driven by said movable plate by means of connecting rods.

Said movable plate is driven by said drive shaft, and said barrel pump comprises a plate with variable inclination relative to said drive shaft, said movable plate being in pivot connection with respect to said plate with variable inclination around the axis of said variable inclination plate.

According to one embodiment of the invention, said pivot link between said movable plate and said variable inclination plate is formed of means for supporting the loads and means for holding the assembly of the two plates.

Advantageously, said pivot link between said movable plate and said variable inclination plate is formed by a stop with tapered rollers and a ball bearing.

Preferably, said tapered roller stop is disposed between an external shoulder of said movable plate and an internal shoulder of said variable inclination plate.

Advantageously, said ball bearing is disposed between an external shoulder of said movable plate and an internal shoulder of said plate with variable inclination.

According to one embodiment, said movable plate is driven by said drive shaft by a finger ball joint.

According to one aspect, said finger ball joint comprises a device for forming a ball joint finger connection in the form of a hollow part of revolution comprising an internal substantially cylindrical surface and an external surface having substantially the shape of a sphere truncated at its two ends. , and said internal surface comprises at least one female groove or groove, and in that said external surface comprises at least one domed groove.

Advantageously, the device for forming a ball joint connection with a finger is mounted on said drive shaft by means of a key or a splined shaft, and said movable plate is mounted on said device by means of at least one cooperating groove. with said at least one domed groove.

Preferably, said movable plate has a partially spherical internal surface.

According to an implementation of the invention, said barrel pump comprises means for controlling the inclination of said plate with variable inclination.

Advantageously, said tilt control means comprises a wheel and worm system.

Preferably, said connecting rods are linked to said movable plate without friction pads.

Furthermore, the invention relates to the use of said barrel pump according to one of the preceding characteristics for a drilling operation, in particular for the injection of drilling mud into a wellbore.

Brief presentation of the figures

Other characteristics and advantages of the device according to the invention will appear on reading the description below of nonlimiting examples of embodiments, with reference to the appended figures and described below.

FIG. 1, already described, illustrates a fixed barrel pump according to the prior art.

Figure 2, already described, illustrates a rotary barrel pump according to the prior art.

FIG. 3 illustrates a barrel pump according to an embodiment of the invention.

FIG. 4 illustrates a device for forming a ball-and-socket connection necessary for the rotation and the inclination of the movable plate according to an embodiment of the invention.

FIG. 5 illustrates the pivot connection between the movable plate and the variable inclination plate according to an embodiment of the invention.

Detailed description of the invention

The present invention relates to a rotary barrel pump. The purpose of the barrel pump is to pump a fluid (for example: water, oil, gas, drilling mud, etc.) by means of a linear displacement of several pistons. This type of pump has the advantage of being compact, having interesting mechanical and volumetric yields, an excellent weight / power ratio. In addition, the rotary barrel pumps are suitable for high pressure pumping.

The barrel pump according to the invention comprises a housing and comprises within the housing:

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

- a movable (rotary) plate driven by the drive shaft: the movable plate is driven relative to the drive shaft, this plate is therefore rotatable, moreover, the movable plate is inclined relative to the drive shaft,

- a cylinder block (called barrel), comprising at least two compression chambers (also called liners) distributed circumferentially (in other words the compression chambers are distributed in a circle), the cylinder block is rotary, and driven by the drive shaft,

- at least two pistons in translation respectively in the compression chambers, the pistons are driven by the movable plate by means of connecting rods (the connecting rods connect, by means of ball joints, the movable plate and the pistons so as to transform the movement of the movable plate in translational movement of the pistons), and the translation of the pistons within the compression chambers pump the fluid, and

a plate with variable inclination relative to the drive shaft, apart from adjusting its inclination, this plate is fixed relative to the casing, and the movable plate is in pivot connection relative to the plate with variable inclination around the axis of the plate with variable inclination (this axis corresponding to a direction normal to the plate, and possibly corresponding to the axis of revolution of the plate with variable inclination in the case where the plate has a disc shape), thus, the inclination of the movable table is identical to the inclination of the table with variable inclination.

The variable inclination of the variable inclination plate allows variable displacement of the pump, by modifying the stroke of the pistons.

Advantageously, the ball joint connections between the connecting rods and the movable plate are implemented without friction pads (there is no friction connection between the connecting rods and the movable plate), this is made possible by the movable plate. Indeed, one of the specificities of the invention is based on the design of the double plate, and more specifically of the connection of the mobile plate with the variable inclination plate and its drive via the power input shaft. Most of the plate pumps on the market are intended for activities with lower flow rates and pressures and the mechanical stresses on the various components of the pump are therefore more limited. In the context of high-speed and high-pressure use of these pumps on the market, the mechanical forces involved are considerable and, for these pumps, the friction pads are essential. In addition, the design of friction pads between the connecting rods and the inclined plate becomes critical, in addition to reducing by a few points the final performance of the pump. The design of a double plate, one fixed and the other rotating, therefore allows an increase in the final efficiency of the pump, bypassing friction pads, and allows use of the pump at high flow and high pressure.

According to one embodiment of the invention, the pivot connection between the movable plate and the variable inclination plate can be formed of means for supporting the loads and means for holding the assembly of the two plates. For example, this pivot link can be formed of a tapered roller stop and a ball bearing. The tapered roller thrust is capable of supporting the axial and radial loads exerted on the plates, the ball bearing makes it possible to hold the assembly of the two plates (mobile and with variable inclination).

According to one aspect of this embodiment, the movable plate can have two external shoulders for the arrangement of the tapered roller thrust bearing and the ball bearing. The shoulder with the smallest diameter may be intended to receive the tapered roller stop and may be located on the side of the movable plate remote from the connecting rods. In addition, the shoulder with the largest diameter may be intended to receive the ball bearing, and may be located near the side of the movable plate close to the connecting rods.

In addition, the variable tilt table can have two internal shoulders for the arrangement of the tapered roller thrust bearing and the ball bearing. The shoulder with the smallest diameter can be intended to receive the tapered roller stop, and can be located towards the center of the plate with variable inclination. In addition, the shoulder with the largest diameter may be intended to receive the ball bearing, and may be located on the side of the variable inclination plate close to the movable plate.

This installation of the tapered roller thrust bearing and the ball bearing by means of the internal and external shoulders allows a simple assembly of the two plates.

According to an implementation of the invention, the movable plate can be driven by the drive shaft by a finger ball joint. A ball-and-socket connection is a connection between two mechanical elements, which has four degrees of connection and two degrees of relative movement; only two relative rotations are possible, the three translations and the last rotation being linked. Generally speaking, it is a ball joint with a finger preventing it from rotating. The operating principle of this type of link is to ensure the transmission of torque between two rotating assemblies whose axes are not collinear.

The ball joint to finger connection allows synchronization of the rotation of the movable plate and the cylinder block (barrel).

According to one aspect of this implementation of the invention, the finger ball joint can be formed by means of a specific device for forming a finger ball joint. The device for forming the finger ball joint can be a hollow part of revolution. It is recalled that in geometry, a part of revolution is a part generated by a closed planar surface rotating around an axis located in the same plane as it and having in common with it no point or only points of its border .

For reasons of clarity of the description, the term “device” is used in the rest of the description to designate the specific device for forming a ball-to-finger connection.

The device for forming the finger ball joint has a substantially cylindrical internal surface. Thus, the hollow of the device is substantially cylindrical. In this way, the device is adapted to be mounted on a cylindrical shaft. The internal surface comprises at least one groove for the insertion of a key or at least one female groove for the insertion of a splined shaft, for the purpose of transmitting the torque between a shaft and the device. The use of a key or spline transmission allows the transmission of significant torque.

The device according to the invention comprises an external surface having substantially the shape of a truncated sphere at its ends. The sphere is truncated by two planes perpendicular to the axis of revolution of the device. This partially spherical shape of the external surface allows a ball joint connection. In addition, the external surface comprises at least one domed groove. The domed groove allows on the one hand to form the finger of the finger ball joint, and on the other hand allows the transmission of significant torque, between the device and an element positioned on the external surface of the device (for example a plate or a disk).

This design of the device for forming a ball-and-socket connection allows a high compactness, a large angular movement, and a simplicity of implementation.

Advantageously, the groove (s) and the groove (s) are parallel to the axis of revolution of the device.

Preferably, the groove or grooves of the external surface have a domed shape parallel to the generally spherical shape of the external surface of the device. Thus, it can be splines with involute circles in order to have the greatest transmissible torque.

According to one aspect of this embodiment of the invention, the external surface comprises a plurality of domed grooves regularly distributed over the circumference of the spherical surface. In this way, a greater torque can be transmitted between the device according to the invention, and the element positioned on the external surface of the device. The grooves are preferably parallel to each other. For example, the external surface of the device can comprise between five and nineteen curved splines, preferably between seven and thirteen, in order to optimize the production and the torque transmissible by the device, as well as to optimize the distribution of the forces in the splines.

Thus, for the connection of a finger ball joint between the drive shaft and the movable plate, the device for forming a finger ball joint is mounted on the drive shaft by means of at least one key or by means of 'a grooved tree. In addition, the movable plate is mounted on the external surface of the device to form a connection with a finger ball joint by means of at least one domed groove (female groove) cooperating with the domed groove or grooves.

Thanks to the invention, a finger ball joint is formed between the drive shaft and the movable plate: the movable plate can rotate by means of the spherical external surface of the device, and the torque can be transmitted from the shaft. to the plate by the key or the splines of the drive shaft and by the domed flute (s).

This is a spherical finger joint at constant speed without sliding. This means that the speed of rotation at the entry of the link is identical to the speed of rotation at the exit of the link, and that this link is made without sliding but by a direct mechanical drive.

This design of the connection allows a ball joint to finger having a high compactness, a large angular clearance, and a simplicity of implementation.

To make the ball joint to finger connection, the movable plate may have a substantially spherical internal surface, provided with female grooves.

In order to facilitate the assembly of the connection, the movable plate can be made up of two half-shells. Alternatively, the movable plate can be made in one piece.

According to one aspect of the invention, the movable plate can comprise a means forming an angular stop. It can be a surface coming into contact with the shaft, for example, the plate can include a conical internal surface coming into contact with the shaft for the maximum angle of travel.

As an alternative to this embodiment of a finger ball joint, the finger ball joint can be a ball joint.

The plates can have substantially the shape of a disc. However, the trays can have any shape. Only the compression chambers (and the pistons) are distributed on a circle.

Advantageously, the pump according to the invention may include a number of pistons between three and fifteen, preferably between five and eleven. Thus, a high number of pistons provides a continuous flow upstream and downstream of the pump.

Conventionally, the pump also has an inlet and an outlet for the fluid to be pumped. The fluid passes through the inlet of the pump, enters a compression chamber, is compressed, then discharged from the pump through the outlet by means of the piston.

According to one embodiment of the invention, the angle of inclination of the plate with variable inclination relative to the axial direction of the drive shaft can be between 70 ° and 90 °. In other words, the variable tilting table (and a fortiori the turntable) can be tilted at an angle between 0 and 20 ° relative to a radial direction of the drive shaft.

In accordance with an implementation of the invention, the barrel pump may include means for controlling the inclination of the plate with variable inclination. For example, this control means may include a wheel and worm system.

According to one aspect of the invention, the barrel can be produced in two parts, a first part being intended for guiding, and the second part being intended for sealing.

FIG. 3 illustrates, schematically and without limitation, a kinematic diagram of a rotary barrel pump according to an embodiment of the invention. The rotary barrel pump 1 comprises a drive shaft 5. The rotation of the drive shaft 5 is carried out by an external source, not shown, for example an electric machine and a gearbox. The drive shaft 5 is rotated relative to the casing 15. In addition, the drive shaft 5 rotates the barrel 6 which has compression chambers 4.

The drive shaft 5 also drives a movable plate 2 by means of a ball joint with finger 9.

The pump 1 also comprises a variable inclination plate 7 which, apart from its inclination adjustment, is fixed relative to the casing 15. The means for adjusting the inclination of the variable inclination plate 7 is not not shown.

The movable plate 2 is in pivot connection with respect to the variable inclination plate 7 around the axis of the variable inclination plate 7.

The pump 1 comprises a piston 3 driven by a translational movement (back and forth movement) within a compression chamber 4.

The back and forth movement of the piston 3 is achieved by means of a connecting rod 8 which connects the movable plate 2 and the piston 3 by means of ball joint connections. This back and forth movement of the piston 3 within the compression chamber 4 makes it possible to pump the fluid.

FIG. 4 illustrates, diagrammatically and in a nonlimiting manner, a device for forming a ball-joint connection with a finger according to an embodiment of the invention. The device 10 is a part of revolution around the axis XX. The device 10 is hollow, and has an internal cylindrical surface 11. The internal surface 11 has a groove 14. The section of the groove 14 is substantially rectangular. The device 10 comprises an external surface 12 having the shape of substantially a truncated sphere at its two ends, the truncation being carried out at the level of two planes perpendicular to the axis XX. The external surface 12 comprises a plurality of curved splines 13, in the illustrated case nine curved splines 13. The curved splines 13 have an external surface substantially parallel to the external surface 12 of the device. These are grooves 13 with involute circles.

FIG. 5 illustrates, diagrammatically and in a nonlimiting manner, the pivot connection between the two plates (mobile and with variable inclination). Figure 5 is a sectional view along a plane containing the axis of the drive shaft 5. In this figure are shown the variable inclination plate 7, the movable plate 2, and connecting rods 8. The connecting rods 8 are in ball joint connection in the movable plate 2 without friction pads.

The axis YY represents the axis of the variable inclination plate 7. The movable plate 2 is in pivot connection on the variable inclination plate 7 around the axis YY of inclination of the variable inclination plate 7. Thus, the inclination of the movable plate 2 is identical to the inclination of the variable inclination plate 7. This pivot connection is formed by a stop for tapered rollers 16 and a ball bearing 18.

The movable plate 2 has two external shoulders 20 and 22 for the arrangement of the tapered roller stop 16 and the ball bearing 18. The shoulder 20 with the smallest diameter is intended to receive the tapered roller stop 16 and is located on the side of the movable plate 2 remote from the connecting rods 8. In addition, the shoulder 22 with the largest diameter is intended to receive the ball bearing 18, and is located near the side of the movable plate 2 near the connecting rods 8.

In addition, the variable inclination plate 7 has two internal shoulders 19 and 21 for the arrangement of the tapered roller stop 16 and the ball bearing 18. The shoulder 19 with the smallest diameter is intended to receive the stop. with tapered roller 16, and is located towards the center of the variable inclination plate 7. In addition, the shoulder 21 with the largest diameter is intended to receive the ball bearing 18, and is located on the side of the inclination plate variable 7 close to the movable plate 2.

FIG. 5 also illustrates the device for forming a finger ball joint 10. This device 10 conforms to the device for forming a finger ball joint illustrated in FIG. 4. The device 5 10 is mounted on the drive shaft 5 at by means of a key 17.

The invention also relates to the use of the pump according to the invention for a drilling operation, in particular for the injection of drilling mud into a wellbore. Indeed, the pump according to the invention is well suited to this use, by its flexibility, its compactness, and its resistance to high pressures.

For example, the pump according to the invention can be dimensioned to operate up to pressures of the order of 1500 bars, that is to say 150 MPa. In addition, the pump according to the invention can be dimensioned to operate at flow rates varying from 30 to 600 m ³ / h.

Claims (13)

claims 1) Barrel pump comprising a casing (15), and comprising within said casing (15): - a drive shaft (5), - a cylinder block (6) comprising at least two compression chambers (4) distributed circumferentially, said cylinder block (6) being driven by said drive shaft (5), - a movable plate (2), - at least two pistons (3) in translation respectively in said compression chambers (4) of said cylinder block (6), said pistons (3) being driven by said movable plate (2) by means of connecting rods (8), characterized in that said movable plate (2) is driven by said drive shaft (5), and in that said barrel pump (1) comprises a plate with variable inclination (7) relative to said drive shaft (5) , said movable plate (2) being in pivot connection with respect to said variable inclination plate (7) about the axis (YY) of said variable inclination plate (7). 2) Pump according to claim 1, wherein said pivot connection between said movable plate (2) and said variable inclination plate (7) is formed of means for supporting the loads and means for holding the assembly of the two plates. 3) Pump according to claim 2, wherein said pivot connection between said movable plate (2) and said variable inclination plate (7) is formed by a tapered roller stop (16) and a ball bearing (18 ). 4) Pump according to claim 3, wherein said tapered roller stop (16) is disposed between an external shoulder (20) of said movable plate (2) and an internal shoulder (19) of said variable inclination plate (7). 5) Pump according to one of claims 3 or 4, wherein said ball bearing (18) is disposed between an external shoulder (22) of said movable plate (2) and an internal shoulder (21) of said variable inclination plate ( 7). 6) Pump according to one of the preceding claims, wherein said movable plate (2) is driven by said drive shaft (5) by a finger ball joint (9). 7) Pump according to claim 6, wherein said finger ball joint (9) comprises a device (10) for forming a ball joint finger connection in the form of a hollow part of revolution comprising an inner surface (11) substantially cylindrical and a external surface (12) having substantially the shape of a truncated sphere at its two ends, and in which said internal surface (11) comprises at least one groove (14) or a female groove, and in that said external surface (12 ) comprises at least one domed groove (13). 8) Pump according to claim 7, in which the device (10) for forming a ball joint with a finger is mounted on said drive shaft (5) by means of a key (17) or of a splined shaft, and said movable plate (2) is mounted on said device (10) by means of at least one groove cooperating with said at least one domed groove (13). 9) Pump according to one of claims 6 or 7, wherein said movable plate (2) has a partially spherical internal surface. 10) Pump according to one of the preceding claims, wherein said barrel pump (1) comprises means for controlling the inclination of said variable inclination plate. 11) Pump according to claim 10, wherein said tilt control means comprises a wheel and worm system. 12) Pump according to one of the preceding claims, wherein said connecting rods (8) are connected to said movable plate (2) without friction pads. 13) Use of said barrel pump (1) according to one of the preceding claims for a drilling operation, in particular for the injection of drilling mud into a wellbore.