PISTON PUMP

The present invention provides a pumping device of the type called a multiple piston,

c'est

to say a pumping device consisting of a drill string reciprocates back and forth within a column of mine drainage, a plurality of pistons being secured along the drill string.The invention also concerns the pistons used for the embodiment of the pumping device described above.The Patent no. 56772 and its certificate of addition is deposited the 23.3.1979 56773 to I ' yaoundé (organization African industrial property) describe a multiple piston pump device of the kind mentioned.The major drawback of the pumping device in the described by the documents mentioned resides constituting pistons which make it up.Indeed, in these pistons, the discharge stream which is integral with the valve stem is movable relative to the body of the piston which is floating so that the relative movement of these two members relative to each other during operation of the pump leads to friction between the elements immersed the pump tube and the drainage, which generate some resistance to pumping and wear of these things. In addition, the seal of the piston is also likely to wear rapidly so that it must be changed quite regularly.The aim of the present invention is to provide a pumping device of the type mentioned at the beginning of the present preamble whose pistons have no more nor seal, nor elements movable relative to each other so that it is maintenance extremely reduced and it has a reduced resistance to pumping.2, 2634253 thus, the pump device according to the invention is characterized in that each piston includes a piston body integral with the cylindrical drill string with one end facing the column bottom drainage consists of a honeycomb structure having an axial bore for the passage of the drill string, discharge being pushed against the honeycomb structure mentioned by a tubular member extending into the body of the piston and through which the pipe string has also secured.According to an advantageous feature of the invention, the discharge valve is comprised of a membrane

circùlaire

flexible plastic whose diameter is substantially equal to the inner diameter of the piston body and comprising an axial opening for passage of the drill string.The absence of seal and moving parts outside the membrane serving as a shutter, said pumping device improves the robustness and efficiency particularly good!natio for providing exceptional rates while suppressing substantially the risk of wear and maintenance requirements which designates the pump device according to the invention essentially country identifier resulting in water is the constraint that the Sahelian country.According to a preferred characteristic of the invention, the rim of the end of the piston body opposite to the honeycomb structure is chamfered so as to return inwardly sand grains that could be on the periphery of the piston body in the event of pumping water particularly sandy, these sand grains being thus

êliminés

and not massed between the walls of the piston body and the column of mine drainage.D. 3, 2 34253 according to another advantageous feature of the invention, the outer diameter of each piston body is substantially smaller than the inside diameter of the pump body.This results in decreased very sensitive of frictions between the submerged and the tube drainage as well as reduced resistance to pumping.According to another advantageous feature of the invention, the column may be used as a drainage bore-lining. For this purpose, use is made of a single tubing, reinforced relative to that used simply for the pump, by suppressing the lining tube used generally intermediate between the borehole and the column of drainage from the pump, thereby saving sensitive in the co T of the drilling provided.Other features and advantages of the invention shall become apparent from the description which still will follow.To the accompanying drawings exemplary'd " non-limiting examples:the fig. -. i is a simplified overview of a pump device according to the invention, - Figure 2 is an exploded perspective view of a piston according to the invention, - Figure 3 is a top view of a piston according to the invention, " - Figure 4 is a view.bottom of the piston of Figure 3 and, Figure 5 - is a sectional view of a section of the submerged pump device in accordance with the invention.To Figure I in, is shown a schematic view of a pump device according to the invention. This pumping device comprises firstly a superstructure outer 1 non-specific to the invention. This superstructure I of-horse style, will not be described in detail since its 4, 2634253 description is given in the aforementioned 56772 OAPI defined only.As well as seen yet the included L, 4 the pump device according to the invention is of the type comprising a drill string 2 reciprocates back and forth within a column of mine pump body 3 which is for example made of PVC tubing or the like, a plurality of pistons 4. being fixed at equal distances along the drill string 2 in a manner be described farther. According to a preferred characteristic of the invention, the pistons 4 are separated by a distance of about 3 meters.The column of mine drainage 3 also includes coupling sleeves 3a steel which permit assembly of the tubular members forming drainage that column 3 (see fig. 1 and 5), and foot 9 which is not specific to the invention. It is also non-specific to the invention, the drill string 2 is constituted with 14 mm diameter of the stretched length of three meters, assembled by threading by means of sleeves 21 mm diameter steel hexagonal 2a on flat (see fig. 5), each said sleeve being screwed and welded to 9.ï ' upper end of each rod. A locknut 2b avoids unthreading of sleeves 2a. Each sleeve 2a mentioned above is protected by a cap made of flexible PVC not shown).According to the invention (see fig. 2 to 4) each piston includes a piston body 4 cylindrical 4a made integral with the pipe string 2 in a manner be described farther, with one end facing the bottom of the column 3 drainage consists (see Figure 2 and 4) of a honeycomb structure fixed 5 6 having an axial bore for the passage of the drill string 2.A delivery valve 7 (see Figure 2 and 3) which consists of a circular membrane flexible plastic is kept pressed against the structure 5" mentioned alveolar 2634253 5 by a tubular member 8 which extends into the body of the piston 4a and is traversed by the drill string 2 which it is also secured.The membrane 7 mentioned forming discharge valve whose diameter is substantially equal to the inner diameter of the piston body 4 and which includes an axial opening 7a for the passage of the drill string 2, present on the opposite side to the cellular structure which allows a collar 7b engagement thereof at the end of the tubular member 8a 8 adjacent the honeycomb structure above its 5. the end of the element 8 is constituted by a tubular element section of reduced diameter with respect to that which extends within the body of the piston 4a, the diameter of said section being determined so that its end 8 of the tubular member is received in the axial hole 6 of the honeycomb structure 5. its penetration of the end of the tubular member 8 into the orifice of the body 6 of the honeycomb structure 5 which is integral with the piston body 4a produces a self-centering of the tubular member 8 within the piston body 4a and therefore self-centering of the membrane 7 forming discharge valve as well as the integration of the three elements constituting the piston 4,

c'est

to say the tubular member 8, the diaphragm 7 and the piston body 4a.According to another feature of the present invention preferentially, the rim i0 of the end of the piston body 4a opposite to the honeycomb structure mentioned above is chamfered to 45 5" so as to return inwardly of the piston body 4a sand grains that could be on the periphery of the pump housing or drainage column 3 in case water pumping too particularly sandy, these grains of sand is thus suppressed and massed between the walls of the pistons 4 and drainage of the column 3.According to another feature of the present invention preferentially, the tubular member 8 has at its end facing away from the discharge valve 8b 7, fins centering the II (three fins offset by an angle of 120" relative to each other in the example shown) which extend radially between the outer surface of the tubular member 8 and the inner surface of the body 4a 4c I plunger.The centering webs II to provide a self-centering of the pistons 4 within the drainage column 3 in use of the pump device in accordance with the mention.Furthermore, the structure

alvéo

!area mentioned above comprises (see Figure 2 and 4) a plurality of arms that extend radially thereof between the wall of the piston body 6 4a passage of the drill string 2. the arms 5a which have along the generatrices of the piston body 4a a height not negligible with respect to the length of the piston body 4a 6a make with the body of the port 6 in height to a suitable support for the membrane 7 forming discharge valve while constituting a honeycomb structure that allows the piston body

régidifier

4a and the passage of water in use of the pump device according to the invention in pressure phase.As shown in Figure 5 the outer diameter of piston body chewing 4a is substantially smaller than the inside diameter of the pump body or column of mine drainage 3. this results in decreased very sensitive of frictions between the submerged parts of the pump and the tube well pump 3 and a reduced resistance to pumping.The pistons 4 are distributed and attached along the entire length of the drill string 2 to equal distance from each other in the following manner. On the side of the element 8 having the tubular 2634253 fins 11 a steel washer 12 is welded on the string 2 (see Figure 5). The piston 4 is held in contact with the steel washer 12 indicated above by a set nut lock nut 13 screwed onto the drill string 2 abutted against the end of the piston body the II 4a opposite to the flanges.Another advantage of the invention is the possibility of using the column of mine pump body 3 drilling as a coating. For this purpose, use is made of a single thickness of tubing 3 reinforced compared to that of the coating used simply for the pump thereby eliminating the tube intermediate

revêtemënt

commonly used between the borehole and the column 3 of the drainage pump. Such an arrangement provides a substantial saving in the cost of doing the drilling provided.It should be noted that the pistons 4 described are devoid of any seal. The latter is indispensable in case of single piston to ensure 1,étanchéité and whose wear often irreversibly causes rapid failure of the pumping device, becomes unnecessary in case of a plurality of the pistons.The lack of seal and moving parts outside the membrane 7 serving as a shutter, as well as the materials used to consummate pistons 4, materials that have a high corrosion resistance, confer robustness and are particularly useful for providing exceptional rates while suppressing substantially the risk of wear and service needs, thereby for the pump device in accordance with the invention essentially country identifier resulting in water is a constraint, such as the Sahelian country.The diameters have reached mine drainage tube 3 and pistons 4 may vary according to the depth of the drilling, 8, 2634253 3 its flow rate and the water requirements of users, of millimeters (

diamìtre

outside the column 3 drainage) up to 160 millimeters and optionally beyond motorized pump in case of great depth.One feature of this type of pumping device resides in effect in the possibility to large flows large depth, the plurality pistons for a constant pressure by plunger regardless of the depth.The characteristics of the liner tube assembly ' drainage column 3 (identical throughout the height of the drill), string 2, piston 4 distributed as described above and foot valve 9 check placed to the lower base of the pump lead placement into a wellbore to a depth sufficient to reach the aquifer regardless of the depth of this region, while preserving the maximum efficiency of the pump. It is important only for predicting, the lining tube-column drainage being now fixed, a special device for the foot valve check 9 housed in the lower part of the tube can be removed at will for review. Only by providing the foot valve 9 at its upper end an internal thread for threaded lower the train back to the well surface.The operation of engaging therein the terminal pins 2 for the return of the pumping device described is as follows. When the string moves up, it carries with it the pistons 4. the membrane 7 of each piston 4 is held in contact with the honeycomb structure 5 of the piston 4 corresponding, so that the assembly becomes relatively sealed and evacuated below, thereby rise the foot valve 9 so that water enters the pump body 4. when the drill string is lowered, it carries with it the pistons downward water from 4.9, 2634253 2 the bottom of the pump body 4 by the foot valve 9 rises up the column of mine drainage 3 through the cells of the honeycomb structure 5 of each piston 4 and pressing the diaphragm 7 of each piston 4.The pump device according to the invention can be adapted to various superstructures according as actuated either by a simple hand lever provided for 1 to 4 people (a woman or a child can actuate it effortlessly for family needs), either by

tractioh

animal using an amusement ride, or by any motor and a transmission mechanism causing reciprocation of the pistons 4. several pumps can further be installed in the same structure.The pump device according to the invention can also be used for extraction of the oil.In this case, only the materials used for the column of mine drainage and the pistons will be to adapt. It may for example be of metal, the viscosity petroleum products using them free from risks of seizure which would occur rapidly upon extraction of sandy and sometimes brackish water.Of course, the invention is not limited to the examples described and represented.The fins covering yarn II of each piston 4 could for example be helical so that water would be caused to swirl in one direction or the other while bringing the sand toward the center of the column of mine drainage.lo and 2634zss