OA11821A - Device for pumping liquid and piston equipping such a device. - Google Patents

Abstract

The pump, comprising a lifting column (1) containing a piston (5) and rod (2), has the piston in the form of a hollow cylindrical body (6) with a coaxial passage (11) and an inner chamber (12) forming spherical seats (13, 15) for a valve (7) with spherical outer surfaces (14, 16) on the rod (2). The valve is connected to the rod by threaded sleeves (4) and locknuts (3). During operation the rod stays centred relative to the piston by the movement of the valve inside the chamber.

Description

1 118 2 1

Liquid pumping device and piston equipping such a device

The present invention relates to a liquid pumping device of the type consisting of a dewatering column having an end in the liquid to be pumped, this column being traversed by at least one rod driven by an alternating movement to drive at least one guide piston, and a piston-guide for such a pumping device.

Pumping devices of the aforementioned type, whose general design has been known for a long time, are widely used in African countries. In view of the state of the art, it is possible to distinguish two families of pumping devices.

The first family concerns pumping devices in which the piston body and the flap valve fitted to the piston are secured to the latige or the drill string. Such an exemplary embodiment is in particular described in patent FR-A-2,634,253. The major drawback of such devices lies in their inability to adapt to possible misalignments 118 2 1 2 between the axis of the dewatering column and the axis These misalignments occur especially during deformation of the dewatering column, generally carried out in synthesis material, 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 made of a deformable flexible membrane requires a frequent renewal of the latter.

The second family of pumping device relates to devices in which the discharge valve, which esttsolidaire of the drill string, is movable relative to the body of the piston which is floating. An exemplary embodiment of such a device. is especially provided in the patent of invention OAPI (African Industrial Property Organization) No. 56,772. The design of such a devicegenerates, during the relative movement of the elements relative to each other, significant friction, in particular between the rod guide and the piston body, again causing rapid wear of the elements. In addition, the design of the valve causes the same disadvantages as those mentioned above for the first family of devices. Other pumping devices have the same disadvantages as those mentioned above. Such is the case of US-A-5.407.333. This patent describes a pump device comprising a piston formed of a cylindrical hollow body and a piston rod at the end of which is solved a spherical valve. Since this ball valve is not displaceable inside the piston body between two axial stop positions, the piston rod is provided with an abutment member that presses against the upper end of the piston body during the downward movement of the rod. piston. For this purpose, the piston rod is slidably mounted sliding contact lelong the inner walls of the drainage column and the 118 2 1 3 piston body. Furthermore, the spherical port valve cooperates with a seat of the piston affecting a conical shape. Both of the above features prevent any relative oscillation between the valve and the piston body to allow the correction of any misalignments between the dewatering column axis and the detent axis.

The above-mentioned problem can not be solved either by US Pat. No. 4,740,141 and US Pat. No. 4,591,316, which describe a pumping device in which the valve and valve seats are of conical shape, which requires a precise positioning of the respective axes of the column ofexhaure and the stem.

An object of the present invention is therefore to provide a pumping device whose piston design allows reduced wear of component parts and improved pumping efficiency.

Another object of the present invention is to provide a pumping device whose design makes it possible to guarantee a perfect seal, even in the case where either the drainage column is not perfectly rectilinear, or the drilling is not perfectly vertical.

Another object of the present invention is to provide a piston whose design makes it possible to remove any deformable element acting as a valve. For this purpose, the subject of the invention is a device for liquid depollage, of the type consisting of a dehydration column having an end in the liquid to be pumped, this column being traversed by at least one moving shaft of an alternating movement for driving at least one guide piston, this guide piston being formed of a hollow axial body, axially through, providing betweenthe inner wall and the rod a coaxial passage. 118 2 1 4 characterized in that this piston-guide comprises, in its inner bore, a chamber having, at least one of the open ends, a spherical bearing constituting a seat, preferably sealing, for a spherical valve, this valve displaceable 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 the operation of the pump, a drive of the piston body maintained automatically centered relative to the column for exhaling by correcting any misalignments between the discharge pipe axis and the shaft axis by means of a relative oscillation between the valve and the piston body.

The design of the pumping device allows a permanent self-centering between the piston body and the exhalation column, self-centering which improves the watertightness of the hydraulic joint between the piston body and the dewatering column and, consequently, the pumping efficiency of the piston. device.

Such a design makes it possible, thanks to the possibility of a multidirectional orientation of the valve relative to the piston body, a reduced wear of the device despite the use of a dewatering column in the matter of not perfectly rectilinear synthesis and / or drilling errors resulting in a borehole forming an angle with lavertical. The invention furthermore relates to a piston-guide for a device for pumping liquid, a device of the type consisting of a dewatering column having an end in the liquid to be pumped, this column being traversed by at least one rod driven by a reciprocating movement for driving at least the piston, characterized in that it is formed of a hollow cylindrical body, axially through, providing between its inner wall and the rod a passagecoaxial, the piston-guide comprising, in its internal bore, a chamber having at least one of its. 118 2 1 5 open ends a spherical bearing constituting a seat, preferably sealing, for a spherical ball valve, this valve, movable in the chamber of the piston body between two axial abutment positions against the piston body, being secured to the rod depiston so as to obtain, during the operation of the pump, a drive of the piston body maintainedautocentred permanently with respect to the exhaure column by correcting any misalignments between the de-winding shaft axis and shaft axis by means of a relative oscillation between valve and piston body. The invention will be better understood on reading the following description of embodiments, with reference to the accompanying drawings, in which: FIG. 1 represents a partial sectional view of a liquid pumping device according to the invention when the valve causes the piston in its ascending movement; Figure 2 shows a bottom view of the lower piston with its grooves allowing the passage of liquid pumped in its downward movement; 3 shows a partial sectional view of the pumping device of FIG. 1 when the valve drives the piston in its downward movement and FIG. 4 is a schematic cross-sectional view of another embodiment of a piston-guide of a device of FIG. pumping according to the invention with an enlarged partial detail view from above of the piéconstitutive one of the seats of the valve.

As mentioned above, the pumping device, object of the invention, is constituted, in a manner known per se, 118 2 1 6 · of a rod 2, or preferably of a train of rods animéda movement of back and forth inside a column 1exheath or pump body. In the case of a drill string, a plurality of pistons are positioned, generally equidistantly, along the drill string. The dewatering column 1 consists, for example, of a tube of synthetic material such as PVC or analog. This dewatering column has an end disposed in the liquid to be pumped into a borehole or well to the aquifer. This end, disposed in the liquid to be pumped, is closed, so asonnonnue, by means of a non-return valve, also calledfoot flap, not shown. This column can be formed of a single tubular element or an assembly of tubular elements.

The reciprocating movement of the rod 2 or of the drill string is obtained via a superstructure, not shown. An exemplary embodiment of such a superstructure is for example provided in OAPI patent No. 56.772. This superstructure, actuated mechanically or mechanically, allows a drive back and forth of the rod 2 or the drill string. The rod 2 or the drill string, thus reciprocated, drives at least one guide piston, or a plurality of guide pins disposed, generally equidistantly, along the rod or the drill string. One of the characteristics of this type of pumping device is in fact in the possibility of obtaining significant flows in great depths, the multiplicity of pistons assuring a constant pressure by piston whatever the depth.

The or each guide piston is therefore formed of a body 5, 6 or hollow cylindrical, axially through, ménageantentre its inner wall and the rod 2 a passage 11coaxial to the rod, as shown in the figures. The role of this coaxial passage 11 will be described below. This guide piston further comprises, in its internal bore, a chamber 12, 12A. In the examples shown in FIGS. 1 to 3, this chamber 12 is formed in one piece with the piston body by simply widening the internal section of the piston body to a predetermined length of piston, the outer diameter of the piston body being maintained and preferably being substantially less than the inner diameter of the borehole. In the example shown in FIG. 4, which illustrates another embodiment of the piston-guide, the chamber 12A is delimited at one of its ends by an inner peripheral lip 18 formed in one piece with the inner wall of the piston body and its another end by a ring 19 provided with a plurality of internal radial fingers 19A, said ring forcing a force in the piston body which can for this purposecomporter an inner peripheral receiving groove. The outer diameter of the piston body 17 is chosen as for it in the same way as the diameter of the piston-guide 5, 6.The chamber 12 or 12A, opening directly into thepassage 11 coaxial formed between inner wall of the piston body and rod 2, has, at least one of its open ends, a sphere 13 spherical. This scope13 constitutes, in the examples shown, a sealing seat for a spherical bearing valve 7. It should be noted that the elements having the same function are represented by the same numerical references in FIGS. 1 to 4.

In the examples shown, the chamber 12 or 12A has, at each of its open ends, a spherical bearing surface 13, 15 capable of constituting a seat for the corresponding spherical bearing surface 14, 16 of the valve 7 at at least two spherical bearing surfaces. However, only the so-called upper spherical surface of the chamber 12 or 12A, able to ensure the seal between the piston body 5, 6 or 17 and the valve 7, is of fundamental importance for the pumping function of the piston. It should be noted that between the two spherical surfaces 13, 15, the walls of the chamber can affect any shape. It is the same with regard to the body of the valve 7 between spherical bearing surfaces 14, 16. In the examples shown in Figures 1 to 3, the chaabre 12 of the body 5, 6 piston and lasoupape 7 are both general spherical appearance. The spherical ports 13, 15 provided on the inner wall of the piston body may be formed of a single component with the latter, as shown in FIGS. 1 to 3, or may be constituted by means of attachments which are connected to the piston body, as shown in FIG. In the example shown in Figure 4, the bearing surface 15 is constituted by the distal end of the radial fingers 19A which are shaped for this purpose. It should be noted that, in function of the desired valve stroke 7 within chamber 12A, the spring 19, whose fingers 19A project from one side, may be positioned with the projecting fingers in the direction of the 12A chamber as illustrated the right finger in Figure 4 or salient in the opposite direction "as the illustrated left finger in Figure 4. The ring 19 provided with fingers 19A radial internal is therefore a reversible part to vary the race voluntarily of the valve 7 to the interior of the chamber 12A. It should be noted that, by spherical bearing means a bearing which can be constituted simply by the flat section of a sphere, that is to say by a ring continued when the range is sealed or discontinuous when the scope forms a valve seat not waterproof.

The valve 7 is thus displaceable in the chamber 12 of the piston body 5, 6 or the chamber 12A of the piston body 17 between two axial abutment positions against the piston body. Each abutment position corresponds to a bearing position of a spherical bearing surface 14 or 16 of the valve 7 against a spherical bearing surface 13 or 15 of the chamber 12 or 12A. This valve 7 is displaceable via the operating rod 2 or the drill string to which it is secured so as to obtain, during operation of the pump, a reciprocating drive of the body 5, 6 or 17 of piston.

In the examples shown, the valve 7 is secured to the piston rod 2 by two tubes 4 spacers threaded on the rod 2 on either side of the valve 7 and immobilized on the rod by appropriate clamping means 3, such as a system nut / nut against. In the examples shown, it is noted that the tubes 4 spacers protrude from the body 5, 6 or 17 piston, thus making permanently accessible the clamping means so as to facilitate the assembly and disassembly of the valve 7.

The presence of a passage 11 coaxial with the rod between body 5, 6 or 17 of piston and rod 2 and the realization of bearing surfaces constituted by spherical bearings between body 5, 6 or 17 of piston and valve 7 allow relative displacement, and in particular a relative oscillation between valve 7 and piston body 5,6. Lapossibility of such a displacement makes it possible to mitigate possible misalignments between the axis of the column 1 of 1'exhaure and the axis of the rod 2 such that the body of piston is maintained self-centered permanently compared with the column 1 d during its displacement training, including in the case of a significant deformation of the dewatering column or when a dewatering column 1 is positioned in a borehole so that it has a deviation from the vertical. Indeed, in a way, the valve may oscillate relative to the inside of the chamber 12 or 12A of the body 5, 6 or 17 piston mounted flotation so that the body 5, 6 or 17 of pistonet the valve assembly 7 / rod 2 can take different relative orientations for maintaining centrally position of the body 5, 6 or 17 of the piston relative to the column 1, while ensuring perfect sealing of all due to the design of spherical ports. On the other hand, by virtue of the above design, the valve 7 can be constituted by a trap element so that it does not have the disadvantages inherent in an elastically deformable part.

Since the piston body 5, 6 is generally formed of a single piece with at least one spherical bearing surface 13 and 15 and a chamber portion 12, it is necessary to provide the piston housing in at least two parts to allow the valve 7 to meet. inside the chamber 12 of the piston body 5, 6. This piston body 5, 6 therefore has a joint plane preferably located in the zone of greater size of the chamber 12 of the piston body. These two parts 5, 6 of the piston body can be assembled by recessing.

Thanks to this two-part design, the piston body can be easily modified. Indeed, the piston-guide can, depending on the design of the two parts of the piston body, to fill only the function or guide function of both piston and guide.In the case where the piston is intended to ensure at the same time the piston and guide function, at least one of the two parts of the piston body 5, 6, in this case the part6 having a spherical bearing surface forming a sealed seat for the valve 7, comprises between the chamber12 and its distal end, corresponding to the endorientée towards the end of the column 1 immersing in the liquid to be pumped, splines. The detail of these splines is shown in Figure 2, the partsplants being shown at 9 and the voids at 10, the reference 8 corresponding to the wall of the piston body from which the grooves originate. These grooves form axial channels opening into the chamber 12 for the passage of the discharge water in the piston function of the guide piston when the valve 7 drives the piston in its downward movement. The other portion 5 of the piston body 5, 6 is in this case a solid portion 118 2 1 11 so that when the valve 7 bears on the spherical bore 13, said upper body of the piston body, this spherical bearing 13 constitutes a sealing seat for the valve 7.

In the case of the piston-guide 17 shown in FIG. 4, the body of the piston-guide is formed in one piece, the sealing lip 18 intended to form the spherical bearing surface 13 constituting a sealing seat of the valve 7 during an upward movement of the rod 2 being made of a single piece with the piston body 17. The other spherical bearing 15 constituting a non-sealed seat for the valve7 is made by means of an insert made as mentioned above of a ring 19 bearing inner radiating fingers 19A. spaced from each other by an anglevoisin of 60 ° so that the ring carries six fingers19A. These fingers 19A delimit between them 20axial channels opening into the chamber 12A for the passage of the discharge water in the pumping function of the piston guide 17 when the valve 7 drives the piston in its downward movement.

The operation of such a pumping device is then the following. When the drill string 2 rises, it carries with it the valves 7. Each valve 7 then supports, via its spherical bearing surface 14 above, against the spherical bearing surface 13, said upper, formed in the chamber 12 or 12A of the The assembly thus becomes sealed and raises a liquid volume while continuing the upward movement of the rods 2. The depression thus produced makes it possible to open the non-return valve disposed in the end of the column immersed in the liquid. to pump, so that the water enters the pump body or column 1. Conversely, when the drill string descends, it carries with it the valve 7 which bears, through its spherical bearing 16 lower, against the so-called lower spherical bearing surface of the piston body 118 2 1 12 and drives the latter in a descending movement. The water contained in the dewatering column passes through the axial channels 10 singing in room 12 of eachpiston.

When the piston-guide is used simply as a guide, it suffices to modify and replace one part of the piston body, namely the solid part, by a part of the piston body similar to the lower part 6 so as to arrange, over the entire height of the piston body, channels for free circulation of the water. In this configuration, not shown, the two parts of the piston body comprise at least, on each side of the chamber of the piston body, axial channels opening into the chamber for the free circulation of liquid on either side of the valve 7. regardless of the relative position between the piston body and the valve. Thus, a permanent self-centering of the piston body with respect to the dewatering column 1 is obtained. It is thus possible, in the same pumping device, to detach alternately, along the drill string 2, pistons acting as both piston and guide and pistons acting solely as a guide.

The pumping device described above can be adapted to various superstructures which will not be described in greater detail hereinafter as they are well known to those skilled in the art.

Such a pumping device can be installed in a well or variable depth borehole while achieving maximum pump performance. Such drilling may sometimes go from a few meters to several hundred meters to reach the zoneaquifère.

Claims (11)

CLAIMS 13 118 2 1 1. A liquid pumping device, of the type consisting of a column (1) dewatering having an end in the liquid to be pumped, this column (1) being traversed by at least one rod (2) driven reciprocating for driving at least one guide piston, said guide piston being formed of a hollow cylindrical body (5, 6, 17), axially traversing, providing between its inner wall and the rod (2) a coaxial passage (11), characterized in that this piston-guide comprises, in its internal bore, a chamber (12, 12A) having, at at least one of its open ends, a spherical bearing surface (13) constituting a seat, preferably a sealing seat, for a valve (7) spherical bearing (14), this valve (7), movable in the chamber (12, 12A) of the body (5, 6, 17) of piston between two axial positions of abutment against the piston body, being secured to the rod (2) depiston so as to obtain, during the operation of the pump , a drive of the piston body (5, 6, 17) maintained permanently autocentered with respect to the dewatering column (1) by correcting any misalignments between the dewatering column axis (1) and the shaft axis (2) by means of a relative oscillation between valve (7) and piston body (5, 6, 17). 2. Device according to claim 1, characterized in that the chamber (12, 12A) has, at each of its open ends, a spherical bearing surface (13, 15) capable of constituting a seat for the spherical bearing surface (14, 16). corresponding of a valve (7) to at least two spherical bearings. 3. Device according to one of claims 1 and 2, characterized in that the chamber (12) of the body (5, 6) of the piston and the valve (7) are generally spherical. 4. Device according to one of claims 1 to 3, 118 2 1 characterized in that the piston body (5, 6) is formed of at least two parts having a joint plane preferably located in the zone of greater dimension of the chamber (12) of the piston body. 5. Device according to claim 4, characterized in that the two parts of the body (5, 6) depiston are assembled by recess. 6. Device according to one of claims 4 and 5, characterized in that at least one (6) of the two partsbodybody (5, 6) of the piston comprises, between the chamber and distal sonextrémité, splines (10). ) forming axial channels opening into the chamber (12) for the passage of the discharge water in the pumping function of the guide piston when the valve (7) drives the piston in its downward movement. 7. Device according to one of claims 4 and 5, characterized in that the two parts of the piston-guide body acting exclusively as a guide comprise at least, on either side of the chamber (12), axial channels opening in the chamber (12) for free circulation of the liquid on either side of the valve (7) independently of the relative position between the piston body (5, 6) and the valve (7). 8. Device according to claim 2, characterized in that the spherical bearing (15) of the chamber (12A) adapted to form a seat for the corresponding spherical bearing (16) of a valve (7) during a downward movement of the rod (2) is constituted by the distal end of internal radial fingers (19A) carried by a ring (19) forcibly fitted inside the piston body (17), said fingers (19A) delimiting between them axial fins opening into the chamber (12A) forpassing the discharge water of the guide piston (17) when the valve (7) drives the guide piston (17) in its downward movement. 9. Device according to claim 8, characterized in that the ring (19) provided with internal radial fingers (19A) is a reversible part to vary at will the stroke of the valve (7) inside the room (12A ). 10. Device according to one of claims 1 to 9, characterized in that the valve (7) is secured to latige (2) maneuvering by two tubes (4) spacer threadedon the rod (2) on both sides of the valve (7) and immobilized on the rod (2) by appropriate clamping means (3,4). 11. Guide piston for a liquid pumping device, device of the type consisting of a column (1) exhaling an end in the liquid to be pumped, this column (1) being traversed by at least one rod (2) animated of a reciprocating movement for driving at least the piston, characterized in that it is formed of a hollow cylindrical body (5, 6, 17), axially through, providing an inner wall and the rod (2) a passage (11 ) coaxial, this piston-guide comprising, in its inner bore, a room (12, 12A) having at least one of its open ends a spherical bearing (13) constituting a seat, preferably sealing, for a valve (7) spherical bearing (14), this valve (7), movable in the chamber (12) of the piston body (5, 6, 17) between two axial abutment positions against the piston body, being fastened to the rod (2) of piston so as to obtain, during the operation of the pump, a The piston body is continuously self-centering relative to the dewatering column by correcting any misalignments between the dewatering column axis (1) and the pressure shaft (2) by means of a relative oscillation between the valve (7) and the body. (5, 6, 17) piston.