EP3698044B1 - Rotating barrel pump with distinct barrel guiding and centering means - Google Patents

Description

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 industry: capital goods, the oil, gas and agri-food industries, the automotive sector, construction (heating, wells, 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 price, minimize maintenance costs or reduce their environmental footprint. These pumps have limits in terms of power, pressure/flow rate torque (i.e. limits which result in phenomena similar to "water hammer" generated by the sinusoidal response of the pressure produced by the crankshaft ), weight, performance and service life. In addition, they do not allow variable displacement and therefore lack flexibility of use.

In addition, in the field of hydrocarbon production, it is currently observed that drilling must reach ever greater 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 of, for example, drilling mud. They must also be reliable, economical, flexible and compact, in order to meet the increasingly demanding demands of the energy sector.

• Excellent rapport poids / puissance
• Très bon rapport qualité / prix
• Rendements mécaniques et volumétriques intéressants
• Possibilité de cylindrée variable en réglant l'inclinaison du plateau

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 power to weight ratio
• Very good value for money
• Interesting mechanical and volumetric yields
• Possibility of variable displacement by adjusting the inclination of the plate

Pumps designed with a barrel operate using a rotating plate system which actuates the various pistons one after the other. When one piston is in the intake phase, the opposite piston is in the 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. Such a barrel pump is for example known from the document U.S. Patent 1,945,391 .

• Les pompes à barillet fixe (figure 1) : dans cette configuration de pompe 1, où le barillet est fixe, c'est le plateau incliné 2 qui tourne (entraîné par l'arbre 5) afin de générer le mouvement des pistons 3 dans leurs chemises 4 (chambre de compression). La liaison entre les pistons 3 et le plateau 2 est alors assuré par des patins rotulés qui frottent sur le plateau 2. L'avantage ici est d'avoir une très faible inertie des pièces en rotation. Toutefois, cette configuration rend difficile la mise en place de cylindrée variable. De plus, dans le cas de pressions et débits importants, les efforts de frottement entre le plateau et les patins ne sont pas négligeables, et rendent complexe voire impossible la réalisation de la pompe.
• Les pompes à barillet avec plateau oscillant : le barillet est fixe dans cette architecture et l'on a deux plateaux, un premier plateau incliné est en rotation et transfère au second plateau uniquement le mouvement d'oscillation. Ainsi, on peut lier les pistons au second plateau oscillant sans la nécessité d'éléments frottants, par exemple avec une bielle liée au piston et au plateau par des liaisons rotules. Cette architecture est adaptée au pompage haute pression du fait de l'absence d'éléments frottant (on en trouve d'ailleurs quelques-unes sur le marché de la géothermie). Elle offre également un excellent rendement mécanique. Cette configuration rend possible la réalisation d'une cylindrée variable, elle reste néanmoins difficile à intégrer et à concevoir.
• Les pompes à barillet rotatif (figure 2) : au sein de la pompe 1, c'est le plateau 2 qui est fixe et le barillet 6 portant les pistons 3 est en rotation, assurant ainsi le mouvement des pistons 3 dans leurs chemises 4 (chambre de compression). La liaison piston 3 - plateau 2 est assurée de la même manière que pour la première configuration. L'avantage de cette architecture est que l'on peut aisément rendre le plateau réglable en inclinaison et ainsi avoir la possibilité de cylindrée variable. En revanche, l'inertie des pièces en rotation augmente de façon non négligeable puisque le barillet et l'ensemble des pistons sont mis en rotation. De plus, pour cette configuration, la maintenance de la pompe est rendue difficile : il est nécessaire de démonter l'ensemble du barillet, y compris la partie « mécanique » de guidage des pistons pour accéder aux conduites d'admission et de refoulement. Généralement, pour cette réalisation, le barillet est réalisé en deux pièces, rendant difficile le montage, car une bonne colinéarité des axes de guidage et de la chambre est nécessaire.

There are three major barrel pump architectures:

• Fixed barrel pumps ( figure 1 ): in this configuration of pump 1, 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 ball joints 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 set up 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 it complex or even impossible to produce the pump.
• Barrel pumps with oscillating 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 oscillating 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 rubbing elements (there are also some on the geothermal market). It also offers excellent mechanical performance. This configuration makes possible the realization of a variable displacement, it nevertheless remains difficult to integrate and to design.
• Rotary barrel pumps ( picture 2 ): within the pump 1, it is the plate 2 which 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 ensured 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 cubic capacity. On the other hand, the inertia of the rotating parts increases significantly since the barrel and all the pistons are rotated. In addition, for this configuration, maintenance of the pump is made difficult: it is necessary to dismantle the entire barrel, including the “mechanical” part guiding the pistons to access the intake and discharge pipes. Generally, for this embodiment, the barrel is made in two parts, making it difficult to assemble, since good collinearity of the guide axes and of 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 achieved by separate guide and centering means. This design makes it possible to differentiate the guiding and sealing functions, which facilitates maintenance and servicing of the pump.

The device according to the invention

• un arbre d'entraînement,
• un bloc cylindre comportant au moins deux chambres de compression réparties circonférentiellement, ledit bloc cylindre étant entraîné par ledit arbre d'entraînement,
• un plateau dont l'inclinaison est réglable,
• au moins deux pistons en translation respectivement dans lesdites chambres de compression dudit bloc cylindre, lesdits pistons étant entraînés par ledit plateau au moyen de bielles.

The invention relates to a barrel pump according to claim 1, 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 platform 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 with respect to the housing by separate guide means and centering means.

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

According to the invention, said first and second parts of said cylinder block are connected by a third part, the diameter of which is smaller than the diameters of said first and second parts of said cylinder block.

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

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

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

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

Advantageously, said splines are arranged at the end of said shaft training.

According to one embodiment, said pistons are in sliding pivot connection in said cylinder block.

According to one aspect, said cylinder block comprises means for sealing with the inlet and discharge pipes of said pump.

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

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

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

Brief presentation of the figures

• La figure 1, déjà décrite, illustre une pompe à barillet fixe selon l'art antérieur.
• La figure 2, déjà décrite, illustre une pompe à barillet rotatif selon l'art antérieur.
• La figure 3 illustre une pompe à barillet selon un mode de réalisation de l'invention.
• La figure 4 illustre le montage relatif des deux barillets selon un mode de réalisation de l'invention.

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

• The figure 1 , already described, illustrates a fixed barrel pump according to the prior art.
• The figure 2 , already described, illustrates a rotary barrel pump according to the prior art.
• The picture 3 illustrates a barrel pump according to one embodiment of the invention.
• The figure 4 illustrates the relative mounting 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 (for example: 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, of having interesting mechanical and volumetric efficiencies, and an excellent weight/power ratio. In addition, rotary barrel pumps are suitable for high pressure pumping.

• un arbre d'entraînement : celui-ci est entraîné en rotation, par rapport au carter par une source d'énergie extérieure, notamment une machine motrice (par exemple thermique ou électrique), en particulier au moyen d'une transmission (par exemple une boîte de vitesses),
• un plateau incliné par rapport à l'arbre d'entraînement, cette inclinaison peut être réglable,
• un bloc cylindre (appelé barillet), comportant au moins deux chambres de compression (appelés également chemises) réparties circonférentiellement (en d'autres termes les chambres de compression sont réparties selon un cercle), le bloc cylindre est rotatif par rapport au carter, et entraîné par l'arbre d'entraînement, et
• au moins deux pistons en translation respectivement dans les chambres de compression, les pistons sont entraînés par le bloc cylindre, et des bielles relient, au moyen de liaisons rotules, le plateau mobile et les pistons de manière à transformer le mouvement du bloc cylindre en mouvement de translation des pistons, et la translation des pistons au sein des chambres de compression réalisent le pompage du fluide.

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

• a drive shaft: this is driven in rotation, relative to the housing by an external energy source, in particular a driving machine (for example thermal or electric), in particular by means of a transmission (for example a gearbox),
• a plate inclined relative to the drive shaft, this inclination can be adjustable,
• a cylinder block (called barrel), comprising at least two compression chambers (also called liners) distributed circumferentially (in other words the compression chambers are distributed along a circle), the cylinder block is rotatable relative to the housing, 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 connecting rods connect, by means of ball joints, the movable plate and the pistons so as to transform the movement of the cylinder block into movement translation of the pistons, and the translation of the pistons within the compression chambers carry out the pumping of the fluid.

The adjustment of the plate inclination 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 separate guide means and 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 the "fusion" of the two parts of the cylinder block (which can be found in the prior art) is to ensure good collinearity of the guide axes and the chamber, since this allows machining all of the guide and sealing means in one go. In addition, this design has a reduced mass, because the assembly functions between any two parts of the cylinder block are eliminated (therefore no more screws, washers, nuts, etc.). In addition, the one-piece design simplifies assembly of the pump barrel and 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 dismantle only the centering means, or only the guide means.

According to one implementation of the invention, the cylinder block may comprise a first part for guiding the pistons and a second part 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 cannot end up 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 intake and bearing). The maintenance of the pump is thus facilitated. According to an exemplary embodiment, the dissociation of the interior spaces can be achieved by means of an internal 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 can be substantially cylindrical and can 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 centers of thrust of the bearings are located between the two bearings). This configuration allows guidance and is suitable for high rotation speeds with heavy 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 can be provided to limit the overhang of the part and to ensure its centering over the entire length. The choice of a ball bearing has the advantage of being suitable for high rotation speeds. 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 include 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 high torque. According to an exemplary embodiment, the female splines can be arranged in the second part of the cylinder block, and optionally 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 can be in a sliding pivot connection in the barrel, in particular in the first part of the cylinder block, in particular by means of a ring. Thus, the pistons are guided for their back and forth movement.

The tray may have substantially the shape of a disc. 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 comprised 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 further comprises an inlet (intake) 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 then discharged from the pump through the outlet by means of the piston.

In addition, the barrel, in particular the second part of the cylinder block, may include means for sealing with the intake and discharge pipes of the pump.

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

According to one implementation 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 endless screw system.

According to one embodiment of the invention, the pump may include a second plate (rotating plate). The second plate can be in pivot connection with respect to the plate with variable inclination 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 connecting rods and plate) without friction pads, which allows better performance of the barrel pump .

The picture 3 illustrates, schematically and in a non-limiting 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 carried out by an external source not shown, for example an electric machine and a gearbox. The drive shaft 5 is in rotation relative to the casing 15. In addition, the drive shaft 5 rotates the cylinder block 6 which comprises compression chambers 4. The pump 1 further comprises a plate with 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 animated 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 joints. This back and forth movement of the piston 3 within the compression chamber 4 makes it possible to pump the fluid.

The figure 4 illustrates, schematically and in a non-limiting 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 part 16 intended for guiding the pistons 3, and a second part 18 comprising the chambers compression 4. In addition, the cylinder block 6 comprises a third part 17 connecting the first part 16 to the second part 18. The first and second parts 16 and 18 have a substantially cylindrical shape. The third part 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 separate the internal spaces of the first and second parts 16 and 18.

The cylinder block 6 is rotatably mounted in the casing 15, thanks to centering means and guide means.

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

The guide means comprise two angular contact roller bearings 11 and 12 mounted between the first part 16 of the barrel 6 and the casing 15. The angular contact roller bearings 11 and 12 are mounted in X.

For guiding each piston 3, the first part 16 of the barrel 6 includes 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 splines 19 at its end, 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 injecting 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. Furthermore, the pump according to the invention can be sized to operate at flow rates varying from 30 to 600 m ³ /h.

Claims (11)

1. Cylinder/plate pump comprising a housing (15), and comprising, within said housing (15):

   - a driveshaft (5),

   - a cylinder block (6) having at least two circumferentially distributed compression chambers (4), said cylinder block (6) being driven by said driveshaft (5),

   - a plate (2) with adjustable inclination,

   - at least two pistons (3) respectively moving in translation in said compression chambers (4) in said cylinder block (6), said pistons (3) being driven by said plate (2) via connecting rods (8),

   characterized in that said cylinder block (6) is pivotably connected to the housing (15) via separate guide means and centring means, in that said cylinder block (6) is in one piece, which comprises a first part (16) for guiding said pistons (3) and a second part (18) comprising said compression chambers (4), and in that said first part (16) and second part (18) of said cylinder block (6) are connected by a third part (17), which has a diameter smaller than the diameters of said first part (16) and second part (18) of said cylinder block (6).
2. Pump according to Claim 1, wherein the interior spaces of said first part (16) and second part (18) of said cylinder block (6) are not in communication.
3. Pump according to either one of Claims 1 and 2, wherein said guide means have two angular-contact roller bearings (11, 12) which are mounted in an X shape on said first part (16) of said cylinder block (6).
4. Pump according to one of the preceding claims, wherein said centring means have a ball bearing (13) mounted on said second part (18) of said cylinder block (6) .
5. Pump according to one of the preceding claims, wherein said cylinder block (6) is driven by said driveshaft (5) by means of flutes (19) provided on said driveshaft (5).
6. Pump according to Claim 5, wherein said flutes are arranged at the end of said driveshaft (5).
7. Pump according to one of the preceding claims, wherein said pistons (3) are in a sliding pivot connection in said cylinder block (6).
8. Pump according to one of the preceding claims, wherein said cylinder block (6) comprises sealing means with intake and delivery pipes for said pump (1).
9. Pump according to one of the preceding claims, wherein said cylinder/plate pump (1) has a means for controlling the inclination of said plate (2).
10. Pump according to Claim 9, wherein said inclination control means has a worm and wheel system.
11. Use of said cylinder/plate pump (1) according to one of the preceding claims for a drilling operation, in particular for injecting drilling mud into a drilled well.

Images