EP3698044A1 - Rotary barrel pump having separate guiding means and centering means for the barrel - Google Patents

Abstract

The present invention relates to a rotary barrel pump, for which the pivot connection between the barrel (6) and the casing (15) is formed by the separate guiding and centering means.

Description

 ROTATING BARREL PUMP WITH DISTINCT BARREL GUIDING AND CENTERING MEANS

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

Nowadays, crankshaft pumps are the most widespread in all sectors of the industry: capital goods, oil, gas and agri-food industries, the automotive sector, building (heating, well, air conditioning, water pumps, etc.) and more specifically for the treatment of water and waste (water and sanitation network). Nevertheless, they are still built from 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 reduce their environmental footprint. These pumps have limits in terms of power, torque pressure / flow (that is to say, the limits that result in phenomena related to "water hammer" generated by the sinusoidal response of the pressure produced by the crankshaft ), weight, yield and shelf 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 drilling must reach deeper and deeper depths, which means working with ever higher injection pressures. Oil companies therefore need very high pressure pumps to reach the depths required for the injection of, for example, drilling muds. The latter must also be reliable, economical, flexible and compact, in order to meet the ever more demanding demands of the energy sector.

Another positive displacement pump technology is the barrel pump. Mainly 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

 • Attractive mechanical and volumetric efficiencies

· Possibility of variable displacement by adjusting the inclination of the plate Pumps designed with a barrel operate using a turntable system that actuates the various 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 forces during the rotation of the shaft driven by the engine.

 There are three major architectures of barrel pumps:

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

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

· The rotary barrel pumps (Figure 2): within the pump 1, it is the plate 2 which is fixed and the barrel 6 carrying the pistons 3 is rotated, thus ensuring the movement of the pistons 3 in their shirts 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 it can easily make the adjustable tray tilt 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, the maintenance of the pump is made difficult: it is necessary to disassemble the entire cylinder, including the "mechanical" guide portion of the pistons to access the inlet and discharge pipes. Generally, for this embodiment, the barrel is made in two pieces, making assembly difficult, as good collinearity of the guide pins and the chamber is necessary. To overcome these drawbacks, the present invention relates to a rotary barrel pump, for which the pivot connection between the barrel and the casing is performed by the separate guiding and centering means. This design makes it possible to differentiate the guiding and sealing functions, which facilitates the maintenance and the maintenance of the pump.

The device according to the invention

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

 - a drive shaft,

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

a tray whose inclination is adjustable,

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

 Said cylinder block is pivotally connected to the housing by guide means and separate centering means.

According to one embodiment of the invention, said cylinder block is a single piece, which comprises a first portion for guiding said pistons, and a second part comprising said compression chambers.

 Advantageously, the interior spaces of said first and second parts of said cylinder block do not communicate together.

 Preferably, said first and second portions of said cylinder block are connected by a third portion, the diameter of which is smaller than the diameters of said first and second portions of said cylinder block.

 According to one aspect, said guide means comprise two angular contact roller bearings X mounted on said first portion of said cylinder block.

 According to one characteristic, said centering means comprise a ball bearing mounted on said second portion of said cylinder block.

 According to one embodiment of the invention, said cylinder block is driven by said drive shaft by means of splines provided on said drive shaft.

 Advantageously, said grooves are arranged at the end of said drive shaft.

According to one embodiment, said pistons are in sliding pivot connection in said cylinder block. In one aspect, said cylinder block comprises sealing means with the inlet and discharge lines of said pump.

 According to one embodiment, said barrel pump comprises means for controlling the inclination of said plate.

 Preferably, said inclination control means comprises a wheel and worm system.

In addition, the invention relates to a use of said barrel pump according to one of the preceding features for a drilling operation, in particular for the injection of drilling muds into a wellbore.

Brief presentation of the figures

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

 Figure 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.

 Figure 3 illustrates a barrel pump according to one embodiment of the invention.

Figure 4 illustrates the relative assembly of the two barrels according to one 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 (eg water, oil, gas, drilling muds, 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 efficiencies, an excellent weight / power ratio. In addition, rotary barrel pumps are suitable for high pressure pumping.

 The cylinder pump according to the invention comprises a housing and comprises within the housing: - a drive shaft: it is driven in rotation relative to the housing by an external source of energy, in particular a prime mover ( for example thermal or electrical), in particular by means of a transmission (for example a gearbox),

a plate inclined with respect to the drive shaft, this inclination can be adjustable, a cylinder block (called a barrel), comprising at least two compression chambers (also called jackets) distributed circumferentially (in other words the compression chambers are distributed in a circle), the cylinder block is rotatable relative to the casing, and driven by the drive shaft, and

 at least two pistons in translation respectively in the compression chambers, the pistons are driven by the cylinder block, and rods connect, by means of ball joints, the movable plate and the pistons so as to transform the movement of the cylinder block into motion of translation of the pistons, and the translation of the pistons within the compression chambers realize the pumping of the fluid.

 The adjustment of the inclination plate allows a variable displacement of the pump, by modifying the stroke of the pistons. According to the invention, the pivot connection between the cylinder block and the casing is formed by guide means and separate centering means.

According to one embodiment of the invention, the cylinder block can be a one-piece piece (that is to say, made in one piece). The advantage of "merging" the two pieces of the cylinder block (which can be found in the prior art) is to ensure good collinearity of the guide pins and the chamber, since this makes it possible to machining all the guiding and sealing means at once. In addition, this design has a reduced mass because the assembly functions between any two parts of the cylinder block are removed (so more screws, washers, nuts, ...). In addition, the one-piece design simplifies the assembly of the pump barrel and the maintenance of the pump in service. Indeed, for maintenance, thanks to the separation of the guide means and the centering means, it is possible to disassemble only the centering means, or only the guide means. According to an implementation of the invention, the cylinder block may comprise a first portion for guiding the pistons and a second portion intended for sealing, the second part comprising the compression chambers of the cylinder block. Thus, the second part is intended for the admission and discharge of the pumped fluid. Once the pump is mounted, the interior spaces of the two parts of the cylinder block are not in communication. In other words, once the pump is mounted, a fluid contained in the first part can not be found in the second part, and vice versa. This design makes it possible to separate the mechanical side of the pump (first part with the moving parts) on its hydraulic side (second part with the intake and the bearing). The maintenance of the pump is found easier. According to an exemplary embodiment, the dissociation of the interior spaces can be achieved by means of an inner cover.

 Preferably, and in order to achieve the pivot connection between the cylinder block and the housing, the first and second parts may have a substantially cylindrical shape.

 According to one aspect of this implementation of the invention, the first and second parts can be connected by a third part. Advantageously, this third part may be substantially cylindrical and may have a diameter smaller than the diameters of the first and second parts.

According to one aspect of this embodiment, the guiding and centering means may comprise two angular contact roller bearings mounted in X (the bearing thrust centers are located between the two bearings). This configuration allows guidance and is suitable for high speeds of rotation with large loads. According to an exemplary embodiment, the two angular contact roller bearings can be mounted on the first part of the cylinder block.

 In addition, a ball bearing may be provided to limit the cantilever of the part and to ensure its centering over the entire length. The choice of a ball bearing has the advantage of being adapted to high speeds of rotation. The loads on this bearing being limited, this choice makes it possible to be compact and light. According to an exemplary embodiment, the ball bearing can be mounted on the second part of the cylinder block. According to one embodiment of the invention, the cylinder block can be driven by the drive shaft by means of splines provided on the drive shaft. In other words, the drive shaft may comprise male splines, and the barrel may include female splines cooperating with the male splines of the drive shaft. The splines make it possible to transmit a large torque. According to an exemplary embodiment, the female splines may be arranged in the second part of the cylinder block, and possibly in the third part of the cylinder block. Alternatively, the female splines can be arranged on the first part of the cylinder block.

Alternatively, the cylinder block can be driven by means of a key provided in the drive shaft. Advantageously, the pistons may be pivotally connected sliding in the cylinder, in particular in the first part of the cylinder block, in particular by means of a ring. Thus, the pistons are guided for their movement back and forth. The tray may be substantially disk-shaped. However, the tray can have any shape. Only the compression chambers (and the pistons) are distributed on a circle.

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

In a conventional manner, the pump further comprises an inlet (inlet) and an outlet (discharge) of the fluid to be pumped. The fluid passes through the inlet of the pump, enters a compression chamber, is compressed, and is discharged from the pump through the outlet by means of the piston.

In addition, the barrel, in particular the second portion of the cylinder block, may comprise sealing means with the inlet and discharge pipes of the pump.

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

According to one embodiment of the invention, the barrel pump may comprise a means for controlling the inclination of the variable inclination plate. For example, this control means may comprise a wheel and worm system. According to one embodiment of the invention, the pump may comprise a second plate (rotating plate). The second plate can be pivotally connected to the variable inclination plate and can be driven by the drive shaft. The drive of the second plate can be achieved by means of a finger ball joint. This design of the pump makes it possible to have a plate which rotates synchronously with the cylinder block, thus making it possible to use ball joints (between rods and plate) without friction pads, which allows a better efficiency of the barrel pump. . FIG. 3 illustrates, schematically and in a nonlimiting manner, a kinematic diagram of a rotary barrel pump according to one embodiment of the invention. The rotary barrel pump 1 comprises a drive shaft 5. The rotation of the drive shaft 5 is performed 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 cylinder block 6 which has compression chambers 4. The pump 1 further comprises a platen. variable inclination 2, which, apart from its adjustment of the inclination, is fixed relative to the housing 15. The means for adjusting the inclination of the variable inclination plate 2 is not shown.

 The pump 1 comprises a piston 3 driven by a translation movement (reciprocating movement) within a compression chamber 4.

 The movement back and forth of the piston 3 is achieved by means of a rod 8 which connects the movable plate 2 and the piston 3 by means of ball joints. This movement back and forth of the piston 3 in the compression chamber 4 allows to pump the fluid.

FIG. 4 illustrates, schematically and in a nonlimiting manner, a sectional view of the barrel according to one embodiment of the invention. This is a sectional view along a plane comprising the axis of the drive shaft 5. The cylinder block 6 comprises a first portion 16 for guiding the pistons 3, and a second portion 18 comprising the chambers In addition, the cylinder block 6 comprises a third portion 17 connecting the first portion 16 to the second portion 18. The first and second portions 16 and 18 have a substantially cylindrical shape. The third portion 17 is also cylindrical and has a diameter smaller than the diameters of the first and second parts 16 and 18.

 A cover 9 is provided at the end of the drive shaft 5 so as to dissociate the internal spaces of the first and second parts 16 and 18.

 The cylinder block 6 is rotatably mounted in the casing 15 by means of centering means and guiding means.

 The centering means comprise a ball bearing 13 mounted between the second portion 18 of the barrel 6 and the casing 15.

 The guide means comprise two angular contact roller bearings 1 1 and 12 mounted between the first part 16 of the barrel 6 and the casing 15. The angular contact roller bearings 1 1 and 12 are mounted in X.

For guiding each piston 3, the first part 16 of the barrel 6 comprises a ring 14 allowing a sliding pivot connection between the piston 3 and the barrel 6. For driving the cylinder block, the drive shaft 5 has at its end splines 19, which cooperate with female splines (not shown) provided in the second and third parts 18 and 17 of the cylinder block 6. 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 muds into a wellbore. Indeed, the pump according to the invention is well suited to this use, for its flexibility, compactness, and resistance to high pressures.

For example, the pump according to the invention can be sized 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 sized to operate at flow rates ranging from 30 to 600 m ³ / h.

Claims

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 tray (2) whose inclination is adjustable,  - 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 plate (2) by means of connecting rods (8),  characterized in that said cylinder block (6) is pivotally connected to the housing (15) by guide means and separate centering means. 2) Pump according to claim 1, wherein said cylinder block (6) is a one-piece piece, which comprises a first portion (16) for guiding said pistons (3), and a second portion (18) comprising said compression chambers (4). 3) Pump according to claim 2, wherein the interior spaces of said first (16) and second (18) portions of said cylinder block (6) do not communicate together. 4) Pump according to one of claims 2 or 3, wherein said first (16) and second (18) parts of said cylinder block (6) are connected by a third portion (17), whose diameter is smaller than the diameters of said first (16) and second (18) portions of said cylinder block (6). 5) Pump according to one of claims 2 to 4, wherein said guide means comprise two angular contact roller bearings (1 1, 12) mounted at X on said first portion (16) of said cylinder block (6). 6) Pump according to one of claims 2 to 5, wherein said centering means comprise a ball bearing (13) mounted on said second portion (18) of said cylinder block (6). 7) Pump according to one of the preceding claims, wherein said cylinder block (6) is driven by said drive shaft (5) by means of splines (19) provided on said drive shaft (5). 8) Pump according to claim 7, wherein said grooves are arranged at the end of said drive shaft (5). 9) Pump according to one of the preceding claims, wherein said pistons (3) are pivotally connected sliding in said cylinder block (6). 10) Pump according to one of the preceding claims, wherein said cylinder block (6) comprises sealing means with the inlet and discharge lines of said pump (1). 1 1) Pump according to one of the preceding claims, wherein said pump barrel (1) comprises means for controlling the inclination of said plate (2). Pump according to claim 11, wherein said inclination control means comprises a wheel and worm system. 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 muds in a wellbore.