WO2014060859A1

WO2014060859A1 - Improved piston pump

Info

Publication number: WO2014060859A1
Application number: PCT/IB2013/055255
Authority: WO
Inventors: Jean-François Olivere
Original assignee: Gwe Pumpenboese Gmbh
Priority date: 2012-06-26
Filing date: 2013-06-26
Publication date: 2014-04-24
Also published as: FR2992373A1; FR2992373B1

Abstract

The invention relates to a pumping device (1) of the type formed by an extraction column (3) having one end in a liquid to be pumped. At least one rod extends through the extraction column (3), said at least one rod (2) performing a reciprocating movement in order to drive at least one piston (4).The pump is characterised in that the piston (4) comprises a hollow cylindrical body (6) provided with at least one longitudinal opening (16), a locknut (7) solidly connected to the rod (2), and a membrane (8) including a first at least partially elastically deformable shell (30) for securing the body (6) to the locknut (7) such that the body (6) can turn slightly at least about two directions perpendicular to one another and to the longitudinal axis of the rod (2). The first shell (30) can (i) deform when the rod (2) drops towards the bottom of the extraction column (3), in order to uncover the openings (16) to allow the passage of the liquid to be pumped, and (ii) press against the body (6) when the rod (2) moves towards the top of the extraction column (3), in order to cover the opening (16) and prevent the passage of the liquid.

Description

IMPROVED PISTON PUMP

Technical area

The present invention relates to a so-called multi-piston type pumping device, that is to say a pumping device consisting of a train of rods moved back and forth inside a column. discharge pipe having an end in the liquid to be pumped, a plurality of pistons being fixed along the drill string. The invention also relates to the pistons used for producing the aforementioned pumping device.

Prior art

Pumping devices of the aforementioned type, whose general design is known for a long time, are mainly and widely used in African countries.

Thus, there is already known an exemplary embodiment, such as that described in patent FR 2,634,253, in which the piston body and the discharge valve fitted to the piston are made integral with the rod or the drill string. Indeed, each piston comprises a cylindrical piston body secured to the drill string whose downward end of the dewatering column consists of a honeycomb structure having an axial orifice for the passage of the drill string, a discharge valve being held in abutment against the aforesaid cellular structure by a tubular element extending in the body of the piston and traversed by the drill string of which it is also made integral, said discharge valve being constituted by a circular diaphragm flexible plastic material whose diameter is substantially equal to the inner diameter of the piston body and comprising an axial opening for the passage of the drill string. The major disadvantage of this type of device lies in their impossibility to adapt to possible misalignments between the axis of the dewatering column and the axis of the stem, these misalignments occurring in particular during a deformation of the dewatering column, generally made in terms of synthesis, during a deviation of the drilling or during an error in the vertical positioning of the column. This results in rapid wear of the entire device. In addition, the presence of a discharge valve consisting of a flexible deformable flat membrane requires frequent renewal of the latter.

To remedy this problem, another type of exemplary embodiment is already known, such as that described in patent FR 2 812 039, in which the piston-guide is formed of a hollow cylindrical body, axially through, sparing between its inner wall and the rod a coaxial passage, this piston-guide comprising, in its inner bore, a chamber having, at at least one of its open ends, a spherical bearing constituting a seat, preferably sealing, for a valve spherical, this valve, movable in the chamber of the piston body between two axial abutment positions against the piston body, being secured to the piston rod so as to obtain, during operation of the pump, a drive of the body of piston maintained permanently self-centered with respect to the dewatering column by correcting any misalignments between the axis of the dewatering column and the shaft axis by means of an oscillation Relative relationship between valve and piston body. However, if this type of pumping device makes it possible to guarantee a perfect seal, even in the event of any misalignments between the axis of the dewatering column and the stem axis, it has the major disadvantage of having its body Piston wear quickly requiring frequent maintenance. Indeed, the action of the valve on the spherical bearing of the piston chamber causes a deformation of said barrel-shaped piston body and therefore rapid and premature wear of said body. Presentation of the invention

Thus, the purpose of the present invention is to propose an alternative to the already known pumping devices that make it possible both to adapt to possible misalignments between the axis of the dewatering column and the shaft axis and to increase the life of certain components of the pumping device according to the invention, in particular the piston, in order to reduce in time the number of intervention and therefore the maintenance cost of said pumping device.

For this purpose, the present invention thus relates to a pumping device of the type consisting of a dewatering column having an end in a liquid to be pumped, said dewatering column being traversed by at least one rod animated by a reciprocating movement for driving at least one piston, characterized in that the piston comprises a hollow cylindrical body provided with at least one longitudinal orifice, a counter-nut integral with said rod and a membrane having a first ferrule at least partly elastically deformable and in particular ensuring the securing of said body on the counter-nut so that said body can slightly articulate at least around two directions perpendicular to each other and to the longitudinal axis of the rod, said first ferrule being suitable, on the one hand, to deform, when the rod descends towards the bottom of the dewatering column, in order to discover said orifices to let the liquid to be pumped and, d on the other hand, to press against the body, when the rod moves up the dewatering column, in order to conceal the orifice and prevent the passage of the liquid. The ferrule is preferably frustoconical and comprises a flexible portion of lesser thickness able to deform by folding towards the rod.

The membrane advantageously comprises a cylindrical shell provided on its outer face with an annular groove having a transverse contour in the general shape of a circular arc and on its inner face with an annular boss having a transverse contour in the general shape of an arc of circle.

Advantageously, the body comprises an outer wall of generally cylindrical shape, an inner wall forming an orifice passing through the body from one side to the other and being centered on the longitudinal axis of said body, a first annular wall, said upper, and a second annular wall, said lower, said inner wall having a cylindrical portion from the lower annular wall and a frustoconical portion from the cylindrical portion and flaring towards the outer wall towards the upper annular wall, the cylindrical portion of the wall internal member comprising a boss in a portion of a torus having a transverse contour in the general shape of an arc of a circle.

The (or) longitudinal orifice (s) are made between the outer and inner walls of the body and opening on one side on the frustoconical portion of the inner wall and on the other side on the lower annular wall.

The counter-nut advantageously comprises a cylindrical portion provided with a groove whose transverse contour is in the general shape of an arc of a circle and a gripping means.

The gripping means is offset relative to the cylindrical portion and the groove.

The invention also relates to a piston for a pumping device according to the invention comprising a hollow cylindrical body provided with at least one orifice longitudinal, a counter-nut integral with said rod and a membrane having a ferrule at least partly elastically deformable and ensuring in particular the fastening of said body on the locknut so that said body can slightly articulate around two directions perpendicular to each other and to the longitudinal axis of the rod, said ferrule being able, on the one hand, to deform, when the rod descends towards the bottom of the dewatering column, in order to discover said orifices for passing the liquid to be pumped and, on the other hand, to be pressed against the body portion, when the rod moves up the dewatering column, in order to conceal the orifice 16 and to prevent the passage of the liquid Brief description of the figures

Other advantages and features will become more apparent from the following description of an alternative embodiment of a pumping device according to the invention with reference to the appended figures in which:

- Figure 1 is a partial vertical sectional view of a liquid pumping device according to the invention when the rod drives the piston in an upward movement;

- Figure 2 is a partial vertical sectional view of the liquid pumping device of Figure 1 when the rod drives the piston in a downward movement.

- Figure 3 is a vertical sectional view of the piston body of the liquid pumping device of Figure 1 with its grooves for the passage of the pumped liquid during the downward movement of said piston;

- Figure 4 is a top view of the body of Figure 3;

FIG. 5 is a vertical sectional view of the piston diaphragm of the liquid pumping device of Figure 1;

FIG. 6 is a view of the piston lock nut of the liquid pumping device of FIG. 1.

Best way to realize the technical invention

As previously described, the pumping device 1, according to the invention, conventionally comprises a rod 2, or preferably a string of rods 2 moved back and forth inside a column 3 d dewatering or pump body. In the case of a drill string 2, a plurality of pistons 4 are positioned, generally equidistantly, along said drill string 2. The dewatering column 3 consists of one or more tubes assembled by sleeves and has an end disposed in the liquid to be pumped into a borehole or well to the aquifer. Said end is conventionally closed by a non-return valve, also called foot valve (not shown in the figures) which is not specific to the invention. This 3 dewatering column may be formed of a single tubular element or an assembly of tubular elements. The reciprocating movement of the rod 2 or the drill string 2 is obtained through a superstructure disposed on the surface (not shown in the figures). This superstructure, actuated manually or mechanically, allows a reciprocating drive of the rod 2 or the drill string 2 and therefore reciprocating the piston 4 or the plurality of pistons 4 inside the column 3 dewatering. One of the characteristics of this type of pumping device 1 lies in the possibility of obtaining large flows in great depths, the multiplicity of pistons 4 ensuring a constant pressure per piston 4 whatever the depth. To avoid any risk of corrosion, all the elements constituting the immersed part of the pumping device 1 are made of non-corrosive material such as stainless steel or else of synthetic material. Thus, the dewatering column 3 is advantageously constituted by a tube of synthetic material such as, for example, PVC or the like, and the rods 2 are made of stainless steel.

Moreover, to form the drill string 2, the latter are at least threaded at each of their ends to allow the assembly of two rods 2 adjacent to each other by means of a tapped female sleeve 5. Each sleeve 5 is immobilized on the rods 2 by any suitable clamping means, such as counter-nuts (not shown in the figures) arranged on either side of said sleeve 5.

With reference to FIGS. 1 and 2, the or each piston 4 comprises a hollow cylindrical body 6, a counter-nut 7 integral with one of the rods 2 of the pumping device 1 and a membrane 8 at least partly elastically deformable, in particular ensuring securing said body on the locknut 7 in a manner to be described later.

According to FIGS. 3 to 6, the body 6 comprises an outer wall 9 of generally cylindrical shape, an inner wall 10 forming an orifice passing through the body 6 from one side to the other and being centered on the longitudinal axis of said body 6, a first wall annular 11, said upper, located on the upper side of the column 3 dewatering and a second annular wall 12, said lower, located on the bottom side of the 3 dewatering column, said upper annular walls 11 and lower 12 joining respectively the upper and lower edges of said outer 9 and inner 10 walls. Said inner wall 10 comprises a cylindrical portion 13 issuing from the lower annular wall 12 and a frustoconical portion 14 issuing from the cylindrical portion 13 and flaring towards the outer wall 9 in the direction of the upper annular wall 11. The cylindrical portion 13 of the inner wall 10 comprises a boss 15 in toroidal portion, said boss 15 having a transverse contour in the general shape of a circular arc. The body 6 further comprises at least one longitudinal orifice 16 formed between its outer 9 and inner 10 walls, and opening on one side on the frustoconical portion 14 of the inner wall 10 and on the other side on the lower annular wall 12 .

According to a preferred embodiment and with reference to Figure 3, the body 6 comprises a plurality of orifices 16 whose cross section has a generally ring-shaped portion, said orifices 16 being distributed uniformly about the longitudinal axis said body 6 so as to form an annular alveolar structure. These orifices 16 allow the upward flow of the column 3 for exhaling the liquid pumped during the descent of the drill string 2.

The frustoconical shape of the inner wall 10 is particularly interesting because it makes it possible to obtain an important passage for the liquid pumped into the piston 2 thus reducing the pressure drops during the descent of the drill string 2 and allowing gravity descent without complementary ballast.

With reference to FIGS. 1, 2 and 6, the counter-nut 7 secured to one of the rods 2 of the pumping device 1 comprises a cylindrical portion 17 provided with a groove 18 whose transverse contour is in the general shape of an arc of circle. Preferably, the radius of the transverse contour of said groove 18 is equal to that of the transverse contour of the boss 15 of the cylindrical portion 13 of the wall 10. The counter-nut 7 further comprises a gripping means 19, advantageously a portion of hexagonal external shape, allowing the rotation of said counter nut 7 with the aid of a tool, such as a flat key, in order to to tighten said counter nut 7 on the associated rod 2. Said gripping means 19 is preferably offset relative to the cylindrical portion 17 and the groove 18 so that it remains permanently accessible, when the piston is mounted along the rod 2, to facilitate assembly and disassembling said piston.

According to a preferred embodiment, there is a piston 4 on each rod 2 to the right of its end, called lower, located on the bottom side of the 3 dewatering column. For this purpose, the counter-nut 7 replaces the counter-nut disposed on the upper side of the dewatering column 3 and serves to immobilize the sleeve 5 of the drill string 2.

With reference to FIGS. 1, 2 and 5, the membrane 8 ensuring in particular the joining of said body 6 to the counter-nut 7 comprises an outer wall 20 of complementary shape to that of the inner wall 10 of the body 6, an inner wall 21 forming an orifice passing through the membrane 8 from one side to the other and being centered on the longitudinal axis of said membrane 8, a first annular wall 22, said upper, situated on the top side of the dewatering column 3 and a second annular wall 23 , said lower, located on the bottom side of the 3 dewatering column, said upper annular walls 22 and lower 23 respectively joining the upper and lower edges of said outer 20 and inner walls 21.

Said outer wall 20 comprises a cylindrical portion 24 issuing from the lower annular wall 23 and a frustoconical portion 25 issuing from the cylindrical portion 24 and flaring outwardly from the membrane 8 in the direction of the upper annular wall 22. The cylindrical portion 24 of the outer wall 20 comprises an annular groove 26 having a transverse contour in the general shape of an arc of a circle, said cylindrical portion 24 and said boss 25 being able to cooperate respectively with the cylindrical portion 24 and the boss 15 of the inner wall 10 of the body 6 to maintain said body 6 in position on the membrane 8.

Said inner wall 21 also comprises a cylindrical portion 27 issuing from the lower annular wall 23 and a frustoconical portion 28 issuing from the cylindrical portion 27 and flaring outwardly of the membrane 8 in the direction of the upper annular wall 22. cylindrical portion 27 of the inner wall 21 comprises an annular boss 29 having a transverse contour in the general shape of an arc of a circle, said cylindrical portion 27 and said boss 29 being able to cooperate respectively with the cylindrical portion 17 and the throat 18 against nut 7 for holding the membrane 8 in position on said counter nut 7.

With this configuration groove-boss, it is clear that once the nut 7 screwed onto one of the ends of a rod 2, the membrane 8 placed on said counter nut 7 and the body 6 set in place on the membrane 8, the body 6 can slightly articulate around two directions perpendicular to each other and to the longitudinal axis of the rod 2 in order to obtain the self-centering of the piston body 6 with respect to the dewatering column 3 for correcting any misalignments between the dewatering column axis 3 and the axis of the rod 2 and preventing the premature wear of said body 6.

Moreover, the respective frustoconical portions 25, 28 of the outer and inner walls 20 and the wall 21 upper ring 22 of the membrane 8 form a first frustoconical ferrule 30 capable of covering the frustoconical portion 14 of the inner wall 10 of the body 6 and in particular the orifices 16.

Likewise, the respective cylindrical portions 24, 27 of the outer and inner walls 21 and the lower annular wall 23 of the membrane 8 form a second cylindrical collar 31 capable of cooperating with the cylindrical portion 13 of the inner wall 10 of the body 6 and the cylindrical portion 17 of the counter-nut 7 for securing said body to said counter nut 7.

In addition, with reference to FIG. 2, this first ferrule 30 comprises a flexible portion 32 of lesser thickness able to deform by folding towards the rod 2, when the rod train 2 descends towards the bottom of the column 3 of FIG. bleeding, in order to discover said orifices 16 to let the liquid to be pumped. On the other hand, when the shank 2 is moving towards the top of the dewatering column 3, said flexible portion 32 comes to press against the frustoconical portion 14 of the internal wall 10 of the body 6 in order to conceal said orifices 16 and prevent the passage of liquid.

The skilled person will have no difficulty in choosing the material to make the membrane 8 and to determine its dimensions and in particular its different thicknesses.

Moreover, we can replace all or part of the bosses by grooves and vice versa for associated grooves without departing from the scope of the present invention.

When the piston 4 is used as a simple guide, it suffices to remove the flexible portion 32 of the first frustoconical ferrule 30 of the membrane 8.

Finally, it is well understood that the frustoconical shape of the membrane 8 is much more resistant than membrane in the form of a flat disk.

Possibility of industrial application

As described above, it is obvious that the pumping device 1 according to the invention is particularly suitable for pumping water in a well or a variable depth drilling that can range from a few meters to several hundred meters. However, it is still possible to use the pumping device 1 for extracting oil by adapting the materials used for the manufacture of the dewatering column 3 and the piston 4.

Finally, it is clear that the present invention is not limited to the sole embodiment of this pumping device 1; it embraces, on the contrary, all variants of implementation and application respecting the same principle.

Claims

1 - Pumping device (1) of the type consisting of a dewatering column (3) having an end in a liquid to be pumped, said dewatering column (3) being traversed by at least one rod (2) driven by reciprocating movement for driving at least one piston (4), characterized in that the piston (4) comprises a hollow cylindrical body (6) provided with at least one longitudinal orifice (16), a counter-nut (7) secured to said rod (2) and a membrane (8) having a first ferrule (30) at least partly elastically deformable and in particular ensuring the securing of said body (6) on the counter-nut (7) so that said body (6) can slightly articulate at least around two directions perpendicular to each other and to the longitudinal axis of the rod (2), said first ferrule (30) being able, on the one hand, to deform, when the rod (2) descends towards the bottom of the dewatering column (3), in order to discover said orifices (16) for leaving passing the liquid to be pumped and, on the other hand, pressing against the body (6), when the rod (2) moves towards the top of the dewatering column (3), in order to conceal the orifice (16) and to prevent the passage of the liquid.

2 - pumping device (1) according to claim 1 characterized in that the first ferrule (30) is frustoconical.

3 - pumping device (1) according to claim 2 characterized in that the first shell (30) comprises a flexible portion (32) of lesser thickness capable of deforming by folding towards the rod (2). 4 - pumping device (1) according to any one of claims 1 to 3 characterized in that the membrane (8) comprises a second shell (31) cylindrical provided on its outer face with a groove (26) annular having a transverse contour in the general shape of a circular arc and on its inner face of an annular boss (29) having a transverse contour in the general shape of an arc of a circle.

5 - pumping device (1) according to claim 4 characterized in that the body (6) has an outer wall (9) of generally cylindrical shape, an inner wall (10) forming an orifice through the body (6) from in part and being oriented on the longitudinal axis of said body (6), a first annular wall (11), said upper, and a second annular wall (12), said lower, said inner wall (10) having a cylindrical portion ( 13) issuing from the lower annular wall (12) and a frustoconical portion (14) issuing from the cylindrical portion (13) and flaring towards the outer wall (9) in the direction of the upper annular wall (11), the portion cylindrical (13) of the inner wall (10) comprising a boss (15) toroidal portion having a transverse contour in the general shape of a circular arc.

6 - pumping device (1) according to claim 5 characterized in that the (s) orifice (s) 16 longitudinal (aux) are formed between the outer wall 9 and inner 10 of the body (6) and opening on one side on the frustoconical portion (14) of the inner wall (10) and on the other side on the lower annular wall (12).

7 - pumping device (1) according to any one of claims 1 to 6 characterized in that the counter nut (7) comprises a cylindrical portion (17) provided with a groove (18) whose transverse contour is in the general shape of an arc of a circle and a gripping means (19). 8 - pumping device (1) according to any one of claims 1 to 6 characterized in that the gripping means (19) is offset relative to the cylindrical portion (17) and the groove (18). 9 - piston (4) for pumping device (1) according to any one of claims 1 to 8 characterized in that it comprises a hollow cylindrical body (6) provided with at least one orifice (16) longitudinal, a counter-nut (7) integral with said rod (2) and a membrane (8) having a first ferrule (30) at least partially elastically deformable and ensuring in particular the securing of said body (6) on the counter-nut (7). ) so that said body can slightly articulate about two directions perpendicular to each other and to the longitudinal axis of the rod (2), said first ferrule (30) being able, on the one hand, to deform when the rod (2) descends towards the bottom of the dewatering column (3), in order to discover said orifices (16) to allow the liquid to be pumped to pass and, on the other hand, to press against the portion body (6), when the rod (2) moves towards the top of the dewatering column (3), in order to conceal the orifice 16 and to prevent the passage of the liquid.