Title of Invention

Reciprocating vertical pump for pumping out liquids present in the ground

Abstract

Reciprocating vertical pump for pumping out liquids present in the ground, the pump comprising : a pump pipe (6) connecting the outlet level of the pump (4) to the bed of liquid to be pumped, whilst being immersed in this bed, a bottom flap valve (9) equipping the lower end of the pumping pipe (6) allowing the liquid to enter the pipe but retaining the column of liquid therein, - a rod (7, 71, 72] carrying one or a plurality of pistons (8) and driven with reciprocating motion (C, D) in order to raise the column of liquid, each piston (8) allowing the liquid to pass during its downward movement in the column and becoming impermeable during its iipward movement, drive means (.10, 11) connected to the rod (7) and bringing about its upward and downward movement inside the pipe (6), 1 the pump being characterized in that : - the piston (8) is formed by a support (81, 82, 83) including a hub extended downwardly and carrying reinforcing legs, the rod (7, 71, 72) extending through the hub and the hub being fixed for translation with the rod (7, 71, 72). a flap valve coming onto the top of the support (81, 82, 83).

Full Text

The present invention relates to a reciprocating vertical pump for pumping out liquids present in the ground, the pump comprising : a pump pipe connecting the outlet level of the pump to the bed of liquid to be pumped, whilst being immersed in the bed, a bottom flap valve equipping the lower end of the pumping pipe allowing the liquid to enter the pipe but retaining the column of liquid therein, - a rod carn/-ing one or a plurality of pistons and driven with reciprocating motion in order to raise the column of liquid, each piston allowing the liquid to pass during its downward movement in the column and becoming impermeable during its upward movement, drive means connected to the rod and bringing about its upward and downward movement inside the pipe. A reciprocating vertical pump of this type is already known and described, in particular, in the document OAPI 06 221 of 23rd March, 1979. Pumps of this type are intended to pump liquids present in the ground such as underground water, petroleum, etc. Known reciprocating vertical pumps which are intended for pumping water are driven manually. They are composed, according to the depth o£ tha bode, either of a vertical rod or of a vertical series of rode carrying one or a plurality of pistons with flap valves. Known pistonis are composed, in generally known wanner, of a cylinder of a certain length having on its periphery, along ono of its edges, particularly the upper edge, a seal sliding in the pumping pipe. Thisf part of the cylinaer is engaged slidingly on a body, for example, formed of fins and terminating at its base in a flap valve. When the cylinder of the piston descende onto tne flap valve, the piston is Ieaktight. In the opposite circumstancea, the liquid can pass through the piston. These two different oxositions between the cylinder and the flap valve coarrespond, respectively, to the downward movement of the piston in the column of water contained in the cylinder of the pump body or puaping pipe and to the upward movement of the column of liquid above the piston, A pumping device with multiple pistons is also known (FR-88 09 575), in which the piston is constituted by a cylinder the base of which has a so-called honeycomb structure. This cylinder is fitted onto the rod which brings about the reciprocating movement. A delivery valve is provided above the honeycomb base and is Kept bearing against the honeycomb structure by by tubular element. This tubular element extends through the Interior of the cylinder and bears against an abutment fixed to the rod. A nut and lock.-nut are provided below the piston, that is, below the honeycomb base of the cylinder, for locking the assembly. The cylinder© of the knovm pistons have the disadvantage of rubbing considerabiy on the internal surface of the pumping column and this friction increaees when the pumping pipe undergoes deformations as a result of ground movements since the pieton Is then forced to follow this deformed path. The seal disposed along the upper edge ol the cylinder and applied against the internal wall of the ]3Uinping pipe, or the cylinder itself, increases this friction because of the pressure exertea by the column of liquid against the seal and the cylinder. The liquids pumped are often muddy and, in the coarse of time, particles are deposited on the valve seats of the piston. The pistons thus lose their lejaktightness, reducing the flow-rate of liquid pumped. For this reason, it is necessary to replace the pistona frequently which increases the running cost of the pump. Since the flap valve is a wearing part, it is under strain and may need replacement- In this case, it is necessary to dismantle the piston assembly to gain access to the flap valve, to withdraw the flap valve to be changed, and to put the new valve in place, For this purpose, it is necessary to remove the piston from the rod completely so as to be able to thread on the new flap valve. This constitutes a relatively lengthy operation in order to replace a very simple item. Moreover, sincia the flap valve is placed in the cylinder when the pump is stopped, the solid partiolas in suspension in the water held in the piston are depositees progressively at the bottom. Since the piston is not perfectly leaktight, the water escapes therefrom and entrains with it the solid particles in suspension which risk besing deposited between the edge of the diephragm and the internal wall of the piston in the space which is necessary to enable the flap valve to be lifted without rubbing against the piston. This situation ie a hindrance for pistons which are not immersed; if, for any reason, the pump is stopped for a certain period, that is, for a few hours or a few days, the solid particles then block the flap valve and experience has shown that, in this case, it is necessary to take all of the pistons out of the water in order to dismantle then and unblock the diaphragms thus atuck, This represents a considerable job and conseguesntly a serious and inevitable disadvantage since, whether the pumps involved are driven by hand or by an electric motor supplied by solar batteries without sufficient buffer battery capacity for continuous operation, the pump necetssarily has to be stopped from time to time. The present invention has the object of eliminatirig these problems and proposes the creation of a reciprocating pump of simple and reliable cDnstruction which enables liquids to be pumped efficiently even in beds of very great depth, with a very regular output even after a prolonged period of use, and which, if necessary, can be maintained or replaced easily or which prevents the flap valve of the piston or pistons which are above the water level when the pump is stopped from being clogged with particles which may be in suspension in the water. Accordingly there is provided a reciprocating vertical pump for pumping out liquids present in the ground, the pump comprising : a pump pipe (6) connecting the outlet level of the pump (4) to the bed of liquid to be pumped, whilst being immersed in this bed, - a bottom flap valve (9) equipping the lower end of the pumping pipe (6) allowing the liquid to enter the pipe but retaining the column of liquid therein, - a rod (7, 71, 72) carrying one or a plurality of pistons (8) and driven with reciprocating motion (C, D) in order to raise the column of liquid, - each piston (8) allowing the liquid to pass during its downward movement in the column and becoming impermeable during its upward movement, - drive means (10, 11) connected to the rod (7) and bringing about its upward and downward movement inside the pipe (6), the pump being characterized in that : the piston (8) is formed by a support (81, 82, 83) including a hub extended downwardly and carrying reinforcing legs, the rod (7, 71, 72) extending through the hub and the hub being fixed for translation with the rod (7, 71, 72) - a flap valve coming onto the top of the support (81, 82, 83). For this purpose, the invention relates to a reciprocating vertical pump corresponding to the type defined above, characterized in that: the piston is formed by a support including a hub extended downwardly and carrying reinforcing legs, the rod extending through the hub and the hub being fixed for translation with the rod, a flap valve coming onto the top of the support in order to obturate the piston under the weight of the column of liquid which is disposed above, or clearing the passage for the liquid when the piston descends in the column of water in the pumping pipe. The pistons are easily mounted on/removed from the rod or at the connection of the elements constituting a series of rods of a pump for a considerable depth. The simplicity of manufacture coupled with the small number of simple parts making up a piston enables the pistons to be assembled and, in particular, installed by unqualified personnel often in rudimentary installation conditions. The same applies to a maintenance operations. Moreover, the structure of the piston prevents practically any deposition of solid particles and any clogging of the flap valve of the piston or of the piston itself in its pipe by virtue of the rinsing of the piston during its operation and at the and of a pumping stage. The particular shape of the piston has the advantage of limiting to the minimum the contact with the internal surfae of the pumping pipe. In the simplest case, the flap valve is constitutud by a diaphragm which can be lifted and which bears on the support in order to support the column of water, according to a feature which is advantageous for operation. The diaphragm forming the flap valve is cut from its outer edge as far as the hole which serves for the passage of tho rod in a manner such that the diaphragro can be engaged on the rod without having to be threaded onto it. The slit disc-shaped diaphragm is placed over the top of the support very easily simply by the loosening of one of the two' nuts holding the support. This operation is carried out very quickly and there is no need; to remove the support from the rod, that is, to proceed with tedious unscrewing. The diaphragm may also be constituted by a plurality of partially overlapping sectors. An embodiment of this type offers the advantage of ease of fitting and removal; it constltutes a flexible form enabling the various sectore to be lifted partially or relative to one another. According to the conditions of use and operation of the pump, the piston will have dimensions closer or. less close to the internal croas section of the pumping pipe. In order to make the pump operate in a light manner and to reduce the power necessary to drive it, a larger clearance is left than if the pump is driven by a motor having available the energy Of an electrical network and not a relatively limited energy source. Moreover, since there is only at moat a linear peripheral contact between the piston and the internal surface of the pipe, even when the pumping pipe is deformed as a result of ground movements this does not iri practice hinder the reciprocating motion of the piston and, in particular, it does not increase the frictional forces between the piston and the internal surface of the pipe. In the case of a pump equipping a water bed at great depth, the flap valve in diaphragm form would not withstand the column of water and, in this case, it is thus made of a rigid material and, more particularly, the support includes legs in the form of right-angled triangles mounted by one of their sides on the upper and auxiliary hubs and joined together throughout the height of the support in order to form, in the upper portion, arms for the support and fixing of the flap valve, the flap valve being formed by disc sectors each connected by one of its radial sides to the upper radial portion of a leg, the other radial side of the flap valve bearing, in an obturating position, on the uppor radial portion of the next leq. This ambodiment has the advantage of permitting particularly effective pumping of a very high column of water without detriment to the smooth-running deacent of the piston or its durability. Moreover, a liquid film forms between the wall of the pipe and the piston or pistons, reducing the friction practically to zero, more especially as between the piston and the wall there is no seal which would scrape off this liquid film. The present invention will be described in greater detail below with the aid of the appended drawings, in which: Figure 1 is a schematic vertical section of a reciprocating vertical pump, Figure 2 is a partial schematic vertical auction of a piston during the descent of its rod, Figure 3 is a schematic vertical eection of the piston duting the upward movement of the rod, Figure 4 is an axial section of the suppo3rt of the piston taken on the lino IV-IV of Figure 5, Figure 5 is a view of the piston support from above, Figure 6 is an exploded view of the piston, Figure 7 is a perspective view of another embodiment of a piston, Figure 8 is a side view of a support shell according to anothor embodiment of the invsntion, Figure 9 is a view from above of two parts of the support in the assembly position, Figure 10 is a partial section taken at IX, showing the complete support assembled on a rod 7, Figure 11 is a perspective view . of another embodiment and assembly of a piston, this view being limited to the upper portion of the support. Figure 12 is a partial section of a piston provided with a skirt. Figures 13A-15B show various embodiments of a piston support. Figure is shows a complete piston provided with a support according to one of the previous embodiments. According to Figure l, the reciprocating vertical pump of the invention includes a base l resting on the ground 2. A vertical fountain 3 is fixed to the base 1; it includes an outlet spout 4 for the liquid which is discharged, for example, into a tank 5. This fountain pipe 3 is extended at its lower end by a pumping pipe 6. This pipe 6 holds an operating rod 7 equipped with one or more pistons 8 which will be described further. The lower end Of the pumping pipe 6 is equipped with a bottom flap valve 9. The rod 7,which may also be a series of rods, that is, an assembly of rods fixed one after another,; according to the depth of the bed in which pumping is carried out, is driven with reciprocating motion toy a mechanism lo which is shown only very schematicaliy. This mechanism 10 is carfried by a frame 11. The mechanism 10 may be driven either manually or by an animal, or even by an internal combustion engine or an electric motor and, in this latter case, an autonomous electrical supply unit, for example, batteries charged by solar cells may be envisaged. The reciprocating vertical movement of the rod 7 and of the pistons S first ensures the raising of the column of liquid bearing on the pistons a and the discharge of a certain quantity of liquid into the tank 5; the rod 7 then causes the pistons 8 to descend inside the column of liquid held in the pumping pipe 6 and retiained by the bottom flap valve 9, When they have reached their lower travel limit, the pistons 8 are raised by the rod 7 and thus lift the column of liquid above each piston. At the same time, the piston above the bottom flap valve 9 creates a partial vacuum beneath it. This partial vacuum draws liquid through the bottom flap valve 9 into the pipe 6. The cycle continues in this manner. Figures 2 and '3 show the structure. of a first embodiment of a piston 8 first, in Figure 2, the descending position of a piston 8 driven by its rod 7 and then, in Figure 3, its upward movement. Xn these drawings, the same reference symbols are used to indicate the same elements as in Figure l. Figure 2 ia a partial axial section of the pumping pipe 6 showing the rod 7 or series of rods formed by a rod portion 71 connected to a rod portion 72 by meana of a threaded seleeve 74; the lower end 73 of the rod 71 is threaded beyond what is necessary simply for the screwing of the sleeve 74 so as to receive the piston 3. This piston 8 which is fixed between a lower nut .12 and an upper nut 13 is composed of a disc-shaped support comaprising an outer rim 81 connected by spokes 82 to an upper hub 83 through which the rod 71 (or its threaded portion 73) extends and a lower hub 84 through which the rod 71 also extends; this lower hub 64 holds the support by legs 8i3 connected to the rim 81. Above the support, the piston 8 includes a flap valve, in this cose formed by a flexible diaphragm 87. The radial shape of the support at the level both of the legs 85 and of the spokes 82 allows the liquid to pass through (to rise) in the direction of the arrows A, B, when the piston descends in the column of liquid in the pumping pipe 6 as indicated by the arrow c. This descent of the piston 8 causes the diaphragro 87 to be lifted. Figure 3 shows the upward movement of the rod 7 (or of the rod eloments 71, 72 in the case of the series of rods) identical to that of Figure 2, according to an upward movement indicated by the arrow D. In ths course of this upward movement, the oolumn of liquid pushes the flap valve 87 against the support and particularly the upper portion of the support of the piston n, that is, the rim 81, the spokes 82 and the upper hub 63, closing the piston in a leaktigh: manner} this enables the column of liquid to be lifted,. It should be noted that, as already indicated, tile piston 8 is fastened to the rod 7 by nuts 12, 13 which also hold the flap valve 67. During the upward movement, the legs 85 transmit some of the forces applied to the outer portion of this support towards the lower hub 84. According to Figures 2, 3, the outer rim 81 of the support has a chawfered or rounded edge, reducing to the minimum the contact between the piston B and the internal surface of the pumping pipe 6. This linear contact along a circle and not along a cylindrical surface, enables all of the deviations or difrences of alignment, for example, curving between the rod 7 and the pumping pipe 6 to be absorbed, reducing to the minimum the frlctional forces which oppose the upward movementes. Moreover, the flap valve 87 is lifted from the support SI, 821 83 in a flexible manner and allows the liquid to rinse the support, thus preventing any deposition of solid particles which would affect the leaktightness of the piaton for the upward movement. Even if particles in suspension should be deposited close to the space between the edge or the rim 81 and the internal surface of the pumping pipe 6 during a prolonged stoppage of the pump, the sticking of the particles will be: eliminated as either upward or downward movement starts again,since the movement is transmitted to the piston 6 directly by the rod or the series [of rods 7, 71, 72- The cross-section of the pumping pipe 6 and that of the piston 8 are circular, without this shape being limiting, and polygonal shapes: hexagonal or square etc. are not excluded. Figures 4, 5,6 show, in greater detail, the structure of a piston such as that described above, Figure 4 shows in section the support with its outer rim 8l, a Eiectioned arm 82, the collar of the upper hub 83, a sectioned leg 65 and the other leg not sectioned, intermedlsite rings 86, as well as the collar of the lower hub 84. Half of the diaphragm 87 is alao shown in section, the other half is not shown. Figure 5, which ie a view from above corresponding to figure i, shows half of the diaphragm and the various parts of the support and particularly the spokes 82, the rings 81, 86 and the upper hub 83, spaces being left between thew for the passage of the liquid to be pumped* The exploded view of Figure 6 shows these varicus parte, that is, the flap valve in the form of a diaphragm 87, the support and its constituent parts 81,: 82, 83, 84, 85, 86. The piston support is a part made, for examiple, in a single piece, for example, of moulded plastics material. The flap valve is preferably made of a flexible material such ae a synthetic rubber or a plastics material. The almensions of the flap valve are such that it covers the holes of the support and reaches close to the Internal surface of the pumping pipe with a space at least sufficient to leave a film of liquid along the wall of the pipe. Although the flap valve 87 may be a disc-shaped element which ia fitted on the rod 7 according to Figure 6, it is advantageously slit, that is, the disc forming the flap valve 87 is cut along a Una BS. This cutting line may be the line joining the two cut edges of the disc.This cutting line 88 goes from the outer edge 89 as far as the hole 90 in the middle of the flap valve 87 which receives the rod 71 (7). The edges of the cutting line 88 nay also overlap as Indicated by the broken line 91. This line is in fact the edge or one disc portion which comes under the upper edge so that the two edges of the disc overlap over the angular sector between the lines 88 and 91. This embodiment of the flap valve allows a worn or damaged flap valve to be replaced easily without the need to dismantle the support itself. Figure 7 is an exploded view of a variant of the piston which is distinguished from the previous pistons by the particular nhapA of tha flap valvo ond tho method in which it in fixed. All of the parts identica to those of the previous embodiments carry the same reference symbols. This variant of the piston is distingushed by the shapa of the flap valve which is constituted by four sectors 92, 93, 94, 95. The sector 92 is Shown separated from the otner sectors shown, which are in the assembled position. These sectors may have the same shapes and the same dimensions and cover each other like fish scales. It is also possible, as the variant of Figure 7 shows, to place two sectors 93 and 95 first cf all in diametrally opposed positions on the support 81-86 and then to place the two sectors 92 and 94 on top of the sectors 93 and 95, thus rbrning a slight overlap shown by the broken lines- in the case of a flap valve of this type, when the piston descends in the water, the upper sectors 92 and 94 lift before the sectors 93 and 95, The sectors 93 cover an angle greater than 1/4 of the disc so as to be able to overlap as indicated. These sectors are also oxtendad by two ourved tabs or hooka 96, 97 at the level of the hole. These two tabs 96, 97 leave a slot 98 between them. The tabs 96, 97 ana the slot 98 allow each. sector, for example the sector 92, to be placed astride a radial arm 82 and between the inner ring 83 and the directly adjacent intermediate ring 86, In the erabodiment shown, the first intermediate ring 86 is very close to the upper hub 83, the distance separating these two rings leaving room for the tabs 96, 97. When the flap valve segments 92-95 are thus; placed on the support previously fixed to the rod 7 (not shown), the upper fixing member, formed by two halves 99A, 99B each terminating in assembly taba 100, 101, is fitted. These two parts 99A, ,99B hava a threaded internal surface 102, 103 so that the two pieces are joined together- forming the same continuous thread. These parts are assembled, for example,, by screws, not shown, as indicated by the broken linest 104. At their bases, the parts 99A, 99B are extended by a half-collar 105, 106? when the part is assembled, these make up a collar pushing the segments 92-95 against the support of the piston 8 previously put in place on the rod. In tact, after the segments 92-95 have been put In place, the two parts 99A, 99B Of the upper fixing member 99 are asseinbled on the threaded portion 73 (Figures ,2 and 3) of the rod 71, 7 and this member 99X, 99B is then sorewad up to clamp the segments 92-95. To ensure locking of this nut so that it does not unscrew under the effect of vibrations, the two parts 99A, 99B may be tightened against one another if a certain clearance exists between them in order to lock the threads of the surfaces 102, 103 in the thresid of the threaded portion 71 and prevent unscrewing. According to a variant, not shown, the flap valve is tulip-shapea, and is fixed near the outer edge of the outer rim 81;the opening of the flap valve may then be provided with a fitting around the rod, forming a seat for the edge of the flap valve. In this variant, the edges of the "petals" of the flap valve on the opening side may be joined by a ring engaged on the rod. According to another variant, the tulip-Bhaped flap valve is constituted by a single frustoconical diaphragm fixed by its outer edge, the inner edge, which borders the hole and optionally has a ring, aurrounding the rod; the latter may also have a part forming the obturation sent against which the edge of the hole of the flap valve bears. Figures a to 10 show another embodiment of a piston support according to the invention. This support is formed by two, for example, exactly identical, parts 200, 201, that is, essentially corresponding to the support off Figure 1 cut through a diametral plane (passing through the axis of the rod). These two halves will thus be manufactured from the same mould. These two parts 200, 201 are assembled on the rod 7 by a collar-type assembly. FOr this purpose, tabes in the upper region and in the lower region of each part 200, 201 complete the parts to form collars. In greater detail, the left-hand part 2001 according to Figure 8 is composed of an outer rim 81A connected by spokes a2A to a hub or inner ring 83A. In fact, both the rim 81A ami the ring 83A, are half-rings, Thia same applies to the intermediate half-rings 86A. The "right-hand" part 201 includes th© same elements as the "loft-hand" part 200 with the same referenc:e symbols in which the suffix A is replaced by the suffix D. Moreover, the half-ring 83A is longer than.the thickness of the spokes 82A or than the outer rin 81A so that tabs 108A, 109k are accessible for the assembly of the two parts 200, 201. The lower hub 84A also corresponds to a half-hub extended on each side by tabs 110A, 111A which are intended to be assembled, again like a collar, with homologous tabs 110B, lllB of the lower hub 84B of the other part 201 (Figure 10). This Figure 10 also shows the beginnings of the spokes SSA and 85B of the two parts 200, 201. The two parts 200, 201 are arranged on either side of the rod 7, according to figure 9. It suffices to assemble then by the tabs of the upper collars (moreover, these are partially hidden by the apokea 82A, 82B). The lower collars will also be assembled. This embodiment of the support offers this twofold advantage of simpler manufacture, since t:he mould corresponds to only half of the shape of the support. Given the symmetry, the same mould can be used to produce the parts 2000,201, This will also considerably facilitate the operations on the installed pump since it is no longer necessary to unscrew the support and remove it along the red 7 or to re-engage it along, the axis of the rod 7, starting from a connection between two rod elements 71. A support can be fixed in any place by this collar mounting. The positioning of the flap valva is also easy in the case of a flap valve like that of Figure 6, This flap valve will be held against the top of the support by a fixing element similar to a collar, not shown In the drawings. The perspective view of Figure 11 shows the support composed of two parts 200, 210 similar to the support shown in Fiqure 9. in Figure 11, for purposes of simplification, the legs 8SA ... are not shown. These legs are preferably situated in planes other than the plane in which the two halves 200, 201 are joined. The underneath portions of the two parts 200, 210 include, along the joining plana, ribs 112A, 113B on which a clip 113, 114 is engaged. This method of assembly may in certain cases, be more advantageous for joining together the upper part of the eupport, in preference to a less accessible connection by screws. Xn the lower regions at the level of the lower hub, on the other hand, the parts 200, 201 nay be connected by a screw connection or also a clip connection like that described herein. In this case, the ribs nay be parallel to the axis of the support and slide vertically. To prevent the clips from coining off under the effect of vibrations* they may be fixed by a small screw. Figure 12 shows a variant of the support, for example, like that of Figure 4. This support is completed, on its periphery, by a skirt 115 leaving a sufficient gap 116 relative to the wall of the pumping pipe to prevent any friction whilst nevertheless craating a loss of head region for slowing the flow of water during pumping. As shown clearly in Figure 12, this skirt 115 is situated under the support and not beside the flap valve 87. Another embodiment of a piston according to the Invention will be described below with the aid of Figures 13A-15B, 16, showing different variants of the support and assembly of thie piston. * The support 300 according to Figure 13A is formed by a tubular hub 384 combining the upper hub and the auxiliary hub of the previous embodiments. The legs 3B5 are constituted by right-angled triangular webs, of which one side is fixed to the hub 384 and the other constitutes a spoke 382 forming a support surface for the flap valve, not shown, Although the different variants of the support include four legs formed by triangular webs, the number may be different, for example, three or five, although an even number is preferable for manufacture because of the plane symmetry which it gives to the support. The variant of Figure 13B corresponds to tha shape of the support of Figure 13A except that it isi in two symmetrical halves along a plane passing through the axis of the rod. These two halves 301', 302' of the support 300' are assembled by their webs provided in a simplified manner with connecting holes 38G'. The variant of the support 400 according to Figure 14A and its embodiment in two symmetrical parts 400' of Figure 14B correspond essentially to Figures 13A, 13B except that the radial sides of the webs 382 are replaced by a surface 482 wider than the thickness of the webs. In the case of Figure 14B, for the surfaces out by the plane of symmetry, the bearing surfaces 482' axe reduced by half and correspond to the surfaces 482'A. The variant Of the support 500 of Figure 15A and its embodiment 500' in two synnetrical parts according to Figfure 15B is distinguished from the previous ones by webs 585,585, the thlcicness of which varies from top to bottom. In the upper portion, the websi585, 585' form a relatively wide bearing surface of the.sane dimension throughout their length* This thickness reduces towards the bottom. In the case of the two-part support 500', the webs 585'A which are cut by the plane of symmetry have a thickness reduced to half the overall thickness. In the different variants of Figures 14A-15B the description of the parts conunon with those of Figures 13A, 13B has not been repeated. The piston according to Figure 16 is composed of a support 600 constituted by one of the supports of Figures 13A-15B and of flap valves 610 in the form of disc sectors of a rigid material. These flap valve sectors 610 are articulated by one (611) of their straight sides to the bearing surface 682 of each web 685 whoreas the other straight side 613 rests freeiy on the bearing ourface 682 of the next web (the reference numerals selected for the various parts of the flap valve are the same). These parts 610 nan pivot about the articulation of their sides 611 and take up, for example, the raised position shown in Figure 16 Tor descending in the liquid (water) , During the lifting movement, the parts of the f:Lap valve 510 are folded down against the bearing surfaces 682 o£ the support. The lifting movement of the parts 610 nay take place practically as far as the vertical without passing it so that the thrust of the water during, the 'lifting of the piston always folds each flap valve portion on the same side. The sense of opening of the parts 6l0 ie preferably the same for all of the parts of the same piston. However, this sense may be reversed from one piston to another to avoid inducing a torque in Figure 7. Tho type of piston according to Figure is ia particularly advantageous for descending to great depths in order effectively to withstand water columns of considerable heights. WE CLAIM : 1. Reciprocating vertical pump for pumping out liquids present in the ground, the pump comprising : - a pump pipe (6) connecting the outlet level of the pump (4) to the bed of liquid to be pumped, whilst being immersed in this bed, - a bottom flap valve (9) equipping the lower end of the pum.ping pipe (6) allowing the liquid to enter the pipe but retaining the column of liquid therein, a rod (7, 71, 72) carrying one or a plurality of pistons (8) and driven with reciprocating motion (C, D) in order to raise the column of liquid, each piston (8) allowing the liquid to pass during its downward movement in the column and becoming impermeable during its upward movement, drive means (10, 11) connected to the rod (7) and bringing about its upward and downward movement inside the pipe (6), the pump being characterized in that: - the piston (8) is formed by a support (81, 82, 83) including a hub extended downwardly and carrying reinforcing legs, the rod (7, 71, 72) extending through the hub and the hub being fixed for translation with the rod (7, 71, 72), - a flap valve coming onto the top of the support (81, 82, 83). 2. The pump as claimed in claim. 1, wherein the flap valve (87) is a diaphragm (88) cut from its outer edge (89) as far as the hole (90) which serves for the passage of the rod (7). 3. The pump as claimed in claim 1, wherein the support is a wheel-shaped element with spokes (82) connected to an upper hub (83) and an auxiliary hub (84) situated below the hub (83) of the wheel and connected to the rim (81) of the wheel by the legs (85). 4. The pump as claimed in claim 1, wherein the support includes legs in the form of right-angled triangles mounted by one of their sides on the upper and auxiliary hubs and joined together throughout the height of the support in order to form, in the upper portion, arms for the support and fixing of the flap valve, the flap valve being formed by disc sectors each connected by one of its radial sides to the upper radial portion of a leg, the other radial side of the flap valve bearing, in an obturating position, on the upper radial portion of the next leg. 5. The pump as claimed in claim 4, wherein the support forms, with the legs, four radial upper portions each receiving a sector of the flap valve which is thus formed of four sections. 6. The pump as claimed in claim 1, wherein the support is formed, in the upper portion, by an outer rim (81) connected by spokes to the upper hub (83). 7. The pump as claimed in claim 1, wherein the flap valve (87) is a discshaped diaphragm covering the entire upper surface of the support (81, 82, 83). 8. The pump as claimed in claim 1, wherein the support is formed of two parts {200, 201), particularly parts symmetrical about a plane, which are assembled on one another, imprisoning the rod (7). 9. The pump as claimed in claim 8, wherein the upper half-hub (83A, 83B) and the lower half hub (84A, 84B) of each part (200, 201) of the support are extended on each side in the joining plane by a tab (108A, 109A; 108B, 109B) for the half hubs (83A, 83B) of the upper part and tabs (llOA, 11 lA; HOB, 11 IB) for the lower half hubs (84A, 84B), for assembly in the manner of a collar. 10. The pump as claimed in claim 7, wherein the flap valve (87) is a disc which is slit (cutting line 88) to enable it to be fitted on the rod (7) without the need for it to be threaded on. 11. The pump as claimed in claim 7, wherein the flap valve is formed of sectors (92, 95) which overlap and terminate at the level of the centre in curved tabs (96, 97) which are intended to go in the spaces between the ring of the hub (83) and an intermediate ring (86), an upper fixing member in two parts (99A, 99B) clamping the sectors against the support. 12. Reciprocating vertical pump for pumping out liquids present in the ground substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Documents:

578-del-1996-abstract.pdf

578-del-1996-claims.pdf

578-del-1996-complete specification (granted).pdf

578-del-1996-correspondence-others.pdf

578-del-1996-correspondence-po.pdf

578-del-1996-description (complete).pdf

578-del-1996-drawings.pdf

578-del-1996-form-1.pdf

578-del-1996-form-13.pdf

578-del-1996-form-2.pdf

578-del-1996-form-3.pdf

578-del-1996-form-4.pdf

578-del-1996-form-6.pdf

578-del-1996-gpa.pdf

578-del-1996-petition-137.pdf

578-del-1996-petition-138.pdf