RU2365785C1 - Pump of diaphragm type for supply of liquids and method of its manufacturing - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: pump is intended for application in drilling and well injection for supply of drilling mud in well. Pump comprises cylinder (2), piston (5) installed in cylinder (2) with the possibility of displacement from drive, and tubular diaphragm (4), which insulates working cavity (10) of pump that communicates with inlet and outlet openings of pump, from water-driven cavity (8), which communicates with internal volume of cylinder, which is adjacent to working surface of piston (5). To produce compact and simple design that makes it possible to produce the pump of diaphragm type on the basis of ordinary piston pump, pump is equipped with jacket (1) placed on top of cylinder (2) with creation of annular chamber limited by at least internal surface of jacket (1) and external surface of cylinder (2), besides, working (10) and water-driven (8) cavities, and also tubular diaphragm (4) that separates them are located in annular chamber. Method is also suggested to make such pump for liquids supply on the basis of piston pump, by means of modification of the latter.

EFFECT: no necessity to use complicated casting molds, lower manufacturing costs.

20 cl, 3 dwg

Description

FIELD OF THE INVENTION

The invention relates to volumetric pumps for supplying liquids, in particular to pumps used in the technique of drilling and completion for supplying a mud solution to a well.

State of the art

To supply mud (flushing or grouting) solutions to the well, piston pumps are used, in particular double-acting double-acting pumps or single-acting three-piston pumps (see A.I. Bulatov et al. Technique and technology for drilling oil and gas wells. - M .: Nedra-Business Center LLC, 2003, p. 539-562). The main disadvantage of these pumps is that their use for pumping abrasive fluids, which are mud solutions, leads to intensive wear of the piston group.

To reduce wear, there are several methods, such as cleaning the solution on cleaning machines, adding organic additives to the solution, or using special alloy steels for the manufacture of the piston group and their corresponding processing, for example, nitriding of cylinders. Nevertheless, these methods provide only a partial solution to the problem. Firstly, it is impossible to completely clear the solution from abrasive particles, and if we take into account that pumps can pump hundreds of cubic meters of solution per hour in deep wells, then cleaning the solution turns out to be a difficult and expensive procedure. Secondly, the use of additives and additives is also an expensive solution. In the case of well plugging, the presence of cement particles in the solution is necessary by definition.

Known designs of volumetric pumps of the diaphragm type with a hydraulic drive of an elastic working body (diaphragm). An example of such a design is disclosed in DE 1528392. The use of diaphragm pumps was an alternative solution to the problem of reducing wear and increasing the pump life when pumping abrasive and aggressive fluids (see copyright certificate SU 826074). RU 2212563 discloses a solution that is closest to the invention in its technical essence, namely a pump for supplying aggressive liquids, containing a cylinder, a piston mounted in the cylinder with the ability to move from the drive, and a tubular diaphragm that isolates the working cavity of the pump in communication with pump inlet and outlet openings, from a hydraulic drive cavity communicating with the internal volume of the cylinder adjacent to the piston working surface. In the pump, made according to the patent RU 2212563, the piston group is isolated from the supplied fluid and is in contact only with a relatively clean working fluid, however, the mutually perpendicular arrangement of the piston group and the tubular diaphragm is a drawback, since the known pump has increased overall dimensions and complex construction. Due to this arrangement, the diameter of the tubular diaphragm in the known pump is relatively small, which necessitates the compression-extension of the diaphragm with a large amplitude to achieve an acceptable working volume, i.e. the volume of fluid displaced by the pump in one cycle.

Disclosure of invention

The aim of the invention is to overcome the disadvantages of the closest analogue, to create a compact, durable simple and inexpensive design of a diaphragm type pump and to develop a simple and inexpensive method of manufacturing such a pump based on existing piston pumps.

To achieve these goals, it is proposed a pump for supplying liquids, mainly abrasive and / or aggressive, containing a cylinder, a piston mounted in the cylinder with the ability to move from the drive, and a tubular diaphragm that isolates the working cavity of the pump, communicating with the inlet and outlet of the pump, from a hydraulic drive cavity in communication with the internal volume of the cylinder adjacent to the working surface of the piston.

The differences of the proposed pump from its closest analogue are that it is equipped with a jacket located on top of the cylinder with the formation of an annular chamber bounded by at least the inner surface of the jacket and the outer surface of the cylinder, the working and hydraulic cavities, as well as the tubular diaphragm separating them located in the annular chamber. In this design, the cylinder itself plays the role of the cylinder sleeve assembly with the jacket.

Thanks to the coaxial arrangement of the piston (hydraulic) and mud (working) parts obtained in this way, the pump becomes more compact and simple. The design of such a pump is suitable for altering piston pumps, the disadvantages of which are discussed above, into diaphragm pumps at costs that are commercially small compared to the costs of equipping wells for drilling mud treatment plants or the use of additives for drilling fluids.

In terms of compactness, the removal of the working cavity directly pumping the supplied liquid to the periphery of the cylinder is advantageous in terms of the possibility of using a significant part of the axial length of the cylinder under the working cavity, as well as the possibility of obtaining a volume of the working cavity comparable with the closest analogue with its smaller thickness in the radial direction, since the volume of the cylindrical cavity is generally proportional to the square of the radius. With the same volume of the working cavity, a large area of the tubular diaphragm allows to reduce the amplitude of its movement, which gives a gain in the durability of the diaphragm.

With regard to simplification of the design, there is no need to use complex injection molds, which are required for the manufacture of the housing perpendicular layout, characteristic of the closest analogue.

The annular chamber, it is advisable to perform axisymmetric, preferably with a contour of a biconvex lens in longitudinal section.

A smooth decrease in the radius of the contour lines of a biconvex lens at the ends of these lines reduces the likelihood of clogging of solid particles present in the pumped liquid or accidentally falling into the working fluid between the movable diaphragm and, accordingly, the wall of the shirt or the wall of the cylinder.

The hydraulic drive cavity can communicate with the internal volume of the cylinder through several bypass holes made in the cylinder and, preferably, evenly distributed around the circumference of the cylinder, and the cylinder together with the jacket can be closed with an end cap on the side facing the piston working surface, i.e. the surface by which the piston acts on the working fluid (oil).

An opening can be made in the end cap for draining the working fluid in between pump starts or for ensuring its circulation through the cleaning filter during operation of the pump. When using the end cap, one edge of the tubular diaphragm can additionally be sandwiched between the cylinder and the end cap for more reliable mounting of the tubular diaphragm.

In the proposed pump, the volume of the hydraulic drive cavity at the end of the discharge stroke of the feed liquid can be approximately two-thirds of the volume of the annular chamber, which eliminates the adverse effect of large particles contained in the feed fluid on the material of the tubular membrane.

The tubular membrane itself can be made of both inelastic and elastic material. Since, in a preferred embodiment of the pump, the working fluid is hydraulic oil, the material of the tubular membrane in this case should be oil-tight and oil-resistant.

To implement the simplest way to control the inlet-outlet of the supplied fluid, a non-return valve can be installed in the pump inlet opening at the beginning of the inlet stroke of the supplied fluid. Accordingly, a check valve can be installed in the pump outlet opening at the beginning of the discharge stroke of the pumped liquid. Naturally, more sophisticated control systems can be used, in which the movement of the valve locking elements is synchronized with the movement of the piston.

A simple way to pair the shirt with the cylinder is to fit the shirt on the cone front and rear of the annular chamber (along the axis of the cylinder), which ensures automatic centering of the shirt and tight contact in conjunction.

The advantageous feature of the proposed pump is that it can be an integral part of a double-acting double-piston mud pump.

The above design features of the proposed pump make it possible to manufacture it not only in the factory, but also in operation, by modifying the piston pumps mentioned at the beginning of the description.

Accordingly, an object of the invention is also a method of manufacturing a diaphragm type pump for supplying liquids, mainly abrasive, based on a piston pump containing a cylinder and a piston mounted in the cylinder with the ability to move from the drive, which is that:

- make a shirt designed for installation on top of the cylinder, equipped with inlet and outlet openings and having such a shape that after installing the shirt its inner surface together with the outer surface of the cylinder bounds the annular chamber,

- perform in the cylinder several bypass holes connecting the internal volume of the cylinder adjacent to the working surface of the piston, with the surface bounding the annular chamber,

- install the shirt on top of the cylinder, placing a tubular diaphragm between them so that the tubular diaphragm divides the annular chamber into a working cavity located on the side of the shirt and a hydraulic drive cavity located on the side of the cylinder.

Before installing the shirt, the cylinder may be suitably prepared. In particular, a recess extending around the circumference of the cylinder can be made on the outside of the cylinder wall. In addition to or instead of this solution, the cylinder wall can be selectively increased (in thickness) to form a recess extending around the circumference of the cylinder.

Brief Description of the Drawings

The proposed pump in one of the options for its implementation is schematically represented in section in the following drawings:

figure 1 is a diagram illustrating an example design of a pump,

figure 2 - the pump shown in figure 1, at the end of the intake stroke (suction),

figure 3 - the pump shown in figure 1, at the end of the cycle of release (discharge).

The implementation of the invention

The proposed pump contains, as shown in figure 1, a cylinder 1, a piston 2 with a rod mounted in the cylinder 1 with the possibility of movement from the drive, and a tubular diaphragm 3. The diaphragm 3 isolates the working cavity 4 of the pump, communicating with the inlet and outlet of the pump , from the hydraulic drive cavity 5, communicating with the internal volume of the cylinder adjacent to the working surface of the piston 2. The cylinder 1 is surrounded on the outside by a jacket 6 mounted on top of it with the formation of an annular chamber, which is limited by the inner surface of the shaft pulleys 6 and the outer surface of the cylinder 1 and in which there are both working 4 and hydraulic 5 cavities, as well as a tubular diaphragm 3 separating these cavities.

The annular chamber is made axisymmetric and has a contour of a biconvex lens in a longitudinal section. In the embodiment shown in FIG. 1, the radius of the contour lines of the biconvex lens is practically constant, but in another embodiment, the radius at the ends of these lines can be variable, in particular, it can gradually decrease.

The hydraulic cavity 5 communicates with the internal volume of the cylinder through several bypass holes 7, made in the cylinder 1 and evenly distributed around the circumference of the latter.

The tubular diaphragm is a shell - a segment of a thin-walled pipe, which can be flexible or inelastic, but in any case quite flexible, durable, impervious to liquids and oil resistant.

The cylinder 1 together with the jacket 6 is closed by the end cap 8 from the side facing the working surface of the piston 2, i.e. to the surface in contact with the working fluid. In the end cap 8, a hole 9 is made for draining the working fluid. For a more reliable fastening of the tubular diaphragm 3, one of its edges is clamped between the cylinder 1 and the end cap 8. The fixing screws and plugs in figure 1 are not shown conditionally.

A check valve 11 is installed in the inlet of the pump, opening at the beginning of the inlet stroke of the pumped liquid, and a check valve 12 is installed in the pump outlet at the beginning of the pump’s outlet, which opens at the beginning of the cycle of the pumped liquid.

Figure 1 also shows that the shirt 6 is associated with the cylinder 1 by landing on a cone in front and behind the annular chamber.

The proposed pump operates as follows.

In the position of the piston 2 shown in FIG. 1, oil is poured into the pump through the hole 10 in the cover 8 as a working fluid. The oil fills the left part of the cylinder and through the bypass holes 7 begins to flow into the hydraulic drive cavity 5. Assume, conditionally, that the oil has occupied such a volume as in figure 1 (the oil is shown by horizontal strokes). Now the piston is moved to the right, and it occupies the position shown in figure 2. Oil from the hydraulic cavity 5 through the holes 7 will enter the cylinder, the volume of the hydraulic cavity 5 will decrease, and the working cavity 4 will increase, the shell 3 will take a different position. At the same time, pumped fluid, for example, drilling fluid, will enter the working cavity 4 through the check valve 11. When moving the piston 2 to the left, to the position shown in figure 3, the oil from the cylinder enters the hydraulic drive cavity 5, increasing its volume and squeezing the drilling fluid out of the working cavity 4 through the check valve 3 through the check valve 12.

Thus, moving the piston 2 from the position shown in FIG. 2 to the position shown in FIG. 3 represents the stroke of the piston, while the drilling fluid does not enter the cylinder 1, and the piston 2 works in oil.

In this scheme, small particles are not scary to cylinder 1, while large particles, having passed through a system of sedimentation tanks, will settle. There is no need for a cleaning machine and organic additives. If necessary, the used oil is drained through the hole 9.

Oil can be cleaned if necessary during work or at intervals.

Given the aspect ratio of the pump elements shown in the drawings, the volume of oil displaced from the cylinder by the piston from the right to the left will take approximately 2/3 of the volume of the annular chamber. The shell thickness in our case does not matter much.

Existing piston pumps with cylinder 1 and piston 2 can be modified as follows.

First, a shirt 6 is made to be installed on top of the cylinder 1, provided with inlet and outlet openings and having such a shape that, after installing the shirt, its inner surface together with the outer surface of the cylinder defines an annular chamber. The shirt can be cast immediately in a ring shape, or assembled from several segments, for example from two halves.

Further, several bypass holes 7 are made in the cylinder 1, connecting the internal volume of the cylinder adjacent to the working surface of the piston 2 with the surface bounding the annular chamber.

Then install the jacket 6 on top of the cylinder 1, placing between them a tubular diaphragm 3 so that the tubular diaphragm 3 divides the annular chamber into a working cavity 4 located on the side of the shirt 6, and a hydraulic drive cavity 5 located on the side of the cylinder 1.

Before installing the jacket 6 in the wall of the cylinder 1, a recess can be made from the outside, passing around the circumference of the cylinder. In addition, the wall of cylinder 1 can be selectively, i.e. to achieve a thickness that varies along the length of the cylinder, build up with the formation of a recess extending around the circumference of the cylinder.

Jacket 6 is conveniently installed on top of cylinder 1 with a cone fit in front and behind the annular chamber.

Thus, the modification mainly affects the mud part of the pump.

A working model of the diaphragm type pump was manufactured on the basis of a double-acting double-piston pump, which developed a pressure of more than 60 atm. With a 270-watt drive from the engine, the model creates a pressure of approximately 30 atm.

Claims (20)

1. A pump for supplying liquids, mainly abrasive and / or aggressive, containing a cylinder (1), a piston (2) mounted in the cylinder (1) with the ability to move from the drive, and a tubular diaphragm (3) that isolates the working cavity (4 ) a pump communicating with the inlet and outlet of the pump from the hydraulic drive cavity (5) communicating with the internal volume of the cylinder adjacent to the working surface of the piston (2), characterized in that it is provided with a jacket (6) located on top of the cylinder (1 ) with the formation of an annular chamber, ogre ness inner jacket surface (6) and the outer surface of the cylinder (1), wherein the operating (4) and hydraulic drive (5) of the cavity and separates them tubular diaphragm (3) disposed in the annular chamber. 2. The pump according to claim 1, characterized in that the annular chamber is made axisymmetric. 3. The pump according to claim 1, characterized in that the annular chamber has in longitudinal section a contour of a biconvex lens. 4. The pump according to claim 3, characterized in that the radius of the contour lines of the biconvex lens at the ends of these lines gradually decreases. 5. The pump according to claim 1, characterized in that the hydraulic drive cavity (5) communicates with the internal volume of the cylinder through several bypass holes (7) made in the cylinder (1). 6. The pump according to claim 1, characterized in that the cylinder (1) together with the jacket (6) is closed by an end cap (8) from the side facing the working surface of the piston (2). 7. The pump according to claim 6, characterized in that an opening (9) is made in the end cap (8) for draining the working fluid. 8. The pump according to claim 6, characterized in that one edge of the tubular diaphragm (3) is sandwiched between the cylinder (1) and the end cap (8). 9. A pump according to any one of claims 1 to 8, characterized in that the working volume of the cylinder between the two extreme positions of the piston (2) is approximately two-thirds of the volume of the annular chamber. 10. A pump according to any one of claims 1 to 8, characterized in that a check valve (11) is installed in the inlet of the pump, opening at the beginning of the inlet stroke of the supplied liquid, and a check valve (12) is opened in the pump outlet, opening at the beginning the stroke of the discharge fluid. 11. A pump according to any one of claims 1 to 8, characterized in that the tubular diaphragm (3) is made of inelastic material. 12. A pump according to any one of claims 1 to 8, characterized in that the tubular diaphragm (3) is made of an elastic material. 13. The pump according to claim 11, characterized in that the tubular diaphragm is made of a material having oil impermeability and / or oil resistance. 14. The pump according to item 12, wherein the tubular diaphragm is made of a material having oil impermeability and / or oil resistance. 15. A pump according to any one of claims 1 to 8, characterized in that the shirt (6) is associated with a cylinder (1) by landing on a cone front and rear of the annular chamber. 16. A pump according to any one of claims 1 to 8, characterized in that it is an integral part of a double-acting double-piston mud pump. 17. The pump according to claim 5, characterized in that the bypass holes (7) are evenly distributed around the circumference of the cylinder (1). 18. A method of manufacturing a diaphragm type pump for supplying liquids, mainly abrasive and / or aggressive, based on a piston pump containing a cylinder (1) and a piston (2) mounted in the cylinder (1) with the possibility of movement from the drive, which consists in what
making a shirt (6) intended for installation on top of the cylinder (1), provided with inlet and outlet openings and having such a shape that after installing the shirt (6) its inner surface together with the outer surface of the cylinder (1) bounds the annular chamber,
perform in the cylinder (1) several bypass holes (7) connecting the internal volume of the cylinder adjacent to the working surface of the piston (2), with the surface bounding the annular chamber,
install the jacket (6) over the cylinder (1), placing a tubular diaphragm (3) between them so that the tubular diaphragm (3) divides the annular chamber into a working cavity (4) located on the side of the shirt (6), and a hydraulic drive cavity ( 5) located on the cylinder side (1). 19. The method according to p. 18, in which before installing the shirt (6) in the wall of the cylinder (1) from the outside, a recess is made that runs around the circumference of the cylinder and / or the wall of the cylinder (1) is selectively expanded to form a recess that runs around the circumference cylinder. 20. The method according to p. 18 or 19, in which the shirt (6) is installed on top of the cylinder (1) with a fit on the cone front and rear of the annular chamber.

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