FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF INVENTION
Self driven reciprocating type water pump
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 025, Maharashtra, India, an Indian Company
INVENTOR
Khedkar Parag Prabhakar, Crompton Greaves Limited, Technology Cell, Switch Gear (S3) Division, A3 MIDC, Ambad, Nashik 422010, Maharashtra, India, an Indian National
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed :

FIELD OF INVENTION
This invention relates to a self driven reciprocating type water pump.
This invention relates particularly to a self driven reciprocating type water pump for use as a booster or auxiliary pump to an electrical pump for pumping water into overhead tanks or to higher levels.
BACKGROUND OF INVENTION
Water pumped or flowing from a source of supply or reservoir into distribution lines or feeder lines, especially in towns and cities, is normally collected in underground tanks, pumped up by electric pumps into overhead tanks and allowed to flow down to utility points under gravity. This is basically because the pressure with which the water flows into the distribution lines or feeder lines is not sufficiently strong enough to lift the water directly into the overhead tanks located at heights meters above the ground level. The energy in the water getting collected in the underground tank is thus wasted without any work being done. Electric pumps consume electrical energy for their operation and require periodic maintenance. Also if there is a breakdown of the electric pumps, water cannot be pumped up into the overhead tanks until the pumps are repaired. This disrupts temporarily water supply to the utility points causing a lot of inconvenience and hardship to the users.
Pneumatic pressure boosters used for driving pneumatic devices such as pneumatic actuators, motors or valves operate on compressed air. A typical pneumatic pressure booster comprises a piston rod comprising a piston at each end thereof. The pistons are located in separate cylinders which are pressurised with air and depressurised alternately by an externally located control circuit so as to cause the pistons to describe
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forward and reverse strokes and compress the air and increase the output pressure. The extreme positions of the pistons are sensed by the control circuit through limit switches located in the cylinders. The operating cost of pneumatic pressure booster is increased because of the use of compressed air. A pneumatic pressure booster also requires a control circuit which is complicated in construction and expensive. It also requires limit switches thereby adding to the cost further. Also in a given construction of the pneumatic pressure booster, the output pressure is fixed and cannot be varied.
OBJECTS OF INVENTION
An object of the invention is to provide a self driven reciprocating type
water pump which does not require any external energy input for its
operation and is cost effective and simple in construction and easy to
operate.
Another object of the invention is to provide a self driven reciprocating type water pump, whose output pressure can be varied in a given construction of the pump.
Another object of the invention is to provide a self driven reciprocating type water pump, which does not require any control circuit for its operation.
Another object of the invention is to provide a self driven reciprocating type water pump, which can be used as a booster or auxiliary pump to an electric pump so as to reduce the energy consumption of the electric pump and realise savings in cost and to ensure water distribution at utility points in case of breakdown of the electric pump.
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DETAILED DESCRIPTION OF INVENTION
According to the invention there is provided a self driven reciprocating type water pump located on an underground water tank and comprising a housing provided with mounting means for mounting it on the underground tank and partitioned into two chambers by a partition wall across the length thereof, one chamber being larger in volume than the other chamber and provided with a pair of inlet ports and a pair of outlet ports, the inlet ports and outlet ports being equally spaced apart along the length of the said one chamber and being located directly opposite to one another, the inlet ports being connected to an incoming water supply through a valve, the outlet ports being connected to the underground tank, the other chamber being provided with a pair of inlet holes and a pair of outlet holes, the inlet holes and outlet holes being equally spaced apart along the length of the said other chamber and being directly opposite to one another, the inlet holes each being connected to the underground water tank through a non-return valve, the outlet holes each being connected to an overhead tank through a non-return valve, the spacing between the inlet holes and outlet holes corresponding to the spacing between the inlet ports and outlet ports, a piston rod reciprocally disposed in the partition wall leak tight and extending into the said one and the other chambers, the piston rod comprising a piston fitted at each end thereof, one piston being located in the said one chamber and the other piston being located in the said other chamber and a valve mechanism for closing and opening alternately diagonally opposite inlet ports and outlet ports during the forward and reverse strokes of the respective piston, the volume ratio between the one chamber and the other chamber being selected to increase the output pressure of the pump.
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The following is a detailed description of the invention with reference to the accompanying schematic drawings, in which :
Figs 1 and 2 are crosssections of the self driven reciprocating type water pump according to an embodiment of the invention at the start of a forward stroke and a reverse stroke of the pistons of the pump respectively;
Fig 3 is an exploded view of the pump of Figs 1 and 2;
Fig 4 is a crosssection at X-X in Fig 1;
Fig 5 is a crosssection at Z-Z in Fig 1;
Fig 6 is a crosssection at A-A in Fig 5;
Fig 7 is an enlarged view at D in Fig 1;
Fig 8a and 8b are isometric views of the slides of the pump of Figs 1
and 2;
Fig 9 is an enlarged crosssectional view at C-C in Fig 1; and
Fig 10 is a schematic illustration of a typical application of the pump of
Figs 1 to 9;
The pump 1 as illustrated in Figs 1 to 9 of the accompanying drawings comprises a cylindrical housing 2 provided with mounting bases 2a and 2b and partitioned into two chambers 3 and 4 by a partition wall 5 across the length thereof. The mounting bases are provided with bolt holes 2c. The end covers 6, 7 of the housing are detachably fitted to the housing using screws 8. Chamber 3 is larger in volume than chamber 4 and is provided with a pair of inlet ports 9 and 10 and a pair of outlet ports 11 and 12. The inlet ports and outlet ports are equally spaced apart along the length of the chamber 3 and are located
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directly opposite to one another. Chamber 4 is provided with a pair of inlet holes 13 and 14 and a pair of outlet holes 15 and 16 as equally spaced apart along the length of the chamber 4 and located directly opposite to one another. The spacing between the inlet holes and outlet holes correspond to the spacing between the inlet ports and outlet ports. 17 is a piston rod reciprocally disposed in the partition wall 5 and extending into the chambers 3 and 4. The piston rod is held in the partition wall 5 leak tight with O-rings 18 and comprises pistons 19 and 20 fitted at its threaded ends marked 17a and 17b using nuts 21. Piston 19 is located in the chamber 3 and is fitted with O-rings 22 around the circumference thereof. Piston 20 is located in the chamber 4 and is fitted with O-rings 23 around the circumference thereof. The O-rings 22 and 23 provide a leak tight joint between the pistons and the respective chambers. A pair of slides 24, 25 are directly oppositely disposed in the chamber 3 with one slide 24 located along the inner surface of the chamber 3 against the inlet ports and provided with a pair of spaced apart holes 26 and 27 along the same line as the inlet ports. The other slide 25 is located along the inner surface of the chamber 3 against the outlet ports and provided with a pair of spaced apart holes 28 and 29 along the same line as the outlet ports. The slides are curved and slide in correspondingly profiled tracks 24a and 25a formed in the chamber 3, respectively. The distance between the holes in the slide 24 is equal to the distance between the inlet ports and outlet ports in the chamber 3. The distance between the holes in the slide 25 is more than the distance between the holes in the slide 24 by twice the stroke of the slides in the chamber 3. 30 and 31 are a pair of fingers associated with each of the slides. The fingers are disposed at opposite sides of the piston in chamber 3 biased by leaf springs 32, 33 respectively against the respective sides of the piston. One ends of the fingers are
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pivoted (pivot marked 34) at the sides of the piston and the other ends of the fingers are tapered marked 35 and slidably located in a pair of channels 36 formed along the length of the respective slide. A pair of apertures 37a, 37b are provided at each end of the slide 24 as equidistantly as the inlet ports in the chamber 3 (Fig 8a). A further pair of apertures 37c, 37d are provided at end of the slide 25 as equally spaced apart as the apertures in the slide 24 (Fig 8b). 38, 39 are a pair of balls associated with each of the slides. The balls are in tandem and are disposed in holders 40 located in cavities (not shown) formed in the side wall of the chamber 3 in the proximity of one end of each of the slides. The balls are biased against the respective end of each slide by compression springs 41 . The distance between the balls correspond to the stroke of the slide. The spring biased balls in tandem protrude into one of the apertures in the channels in the slides at one ends thereof one after the other so as to retain the slides in position as explained in the following description of cyclic operation of the pump. 42 is a replaceable liner located in chamber 4 and provided with holes 43a, 43b, 43c and 43d corresponding to the inlet holes and outlet holes in the chamber 4. The liner is held in position by screw 42a extending into it through the sidewall of the chamber 4. As shown in Fig 10 of the accompanying drawings, the pump of Figs 1 to 9 is located on an underground tank 44 and mounted on the tank with bolts (not shown) passing through the bolt holes 2c in the mounting bases 2a and 2b of the housing. The inlet ports 9 and 10 are connected to an incoming water supply line 45 through a valve 46 and lines 46a and 46b and the outlet ports 11 and 12 are connected to the underground tank via lines 46c, 46d and 46e. The inlet holes 13 and 14 are connected to the underground tank through lines 46f, 46g and 46h and non-return valves 47a and 47b, respectively. The outlet holes 15 and 16 are
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connected to an overhead tank (not shown) through lines 46i, 46j and 46k and non-return valves 48a and 48b, respectively. The ground level is marked 45a in Fig 10. 49 is an electric pump located over the underground with the suction line 50 extending into the underground tank and the discharge line 51 connected to the overhead tank. The operation of the pump of the invention is cyclic and is as described below:
Due to the distance between holes 26 and 27 in the slide 24 being equal to the distance between the inlet ports and outlet ports in chamber 3 and distance between holes 28 and 29 in the slide 25 being more than the distance between holes 26 and 27 in the slide 24 by twice the stroke of the slides in the chamber 3, the slides move together in the chamber 3 such that the holes in the slides are offset with respect to one another and diagonally opposite inlet ports and outlet ports are closed and opened by the slides alternately during the forward and reverse strokes of the piston in the chamber 3 as seen in Figs 1 and 2. At the start of a cycle of operation of the pump, the positions of the pistons in chambers 3 and 4 and the slides in chamber 3 are as shown in Fig 1. Inlet port 9 is aligned with hole 26 in slide 24 and outlet port 12 is aligned with hole 29 in slide 25. Inlet port 10 is misaligned with hole 27 in slide 24 and outlet port 11 is misaligned with hole 28 in slide 25. Inlet hole 13 is opened and inlet hole 14 is closed and outlet hole 15 is closed and outlet hole 16 is opened by the respective valves 47a, 7b, 48a and 48b. Valve 46 is opened so that incoming water in the supply line 45 enters the space in the chamber 3 between end cover 6 and piston 19 via the inlet port 9 and corresponding hole 26 in the slide 24 . The water in the space in the chamber 3 between the end cover 6 and piston 19 develops a positive
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pressure against the piston 19 and causes the piston 19 to describe a forward stroke in the direction of the partition wall 5. The piston 19 slides forward in the direction of the partition wall 5 against the slides 24 and 25 with the fingers 30 and 31 engaged in the respective channels 36 in the slides 24 and 25. The fingers slide in the channels and move forward along with the piston 19. As the piston 19 moves forward, the water in the space in the chamber 3 between the piston 19 and partition wall 5 is forced out through the hole 29 in the slide 25 and corresponding outlet port 12 into the underground tank. Simultaneously, piston 20 also moves forward in chamber 4 in the direction of the end cover 7. As the piston 20 moves forward, the water in the space in the chamber 4 between the end cover 7 and the piston 20 is pressurised and forced out through the hole 43d in the liner and corresponding outlet hole 16 into the overhead tank. When the piston 20 is moving forward in the chamber 4 suction is created in the space in the chamber 4 between the piston 20 and the partition wall 5 and water in the underground tank is sucked into the space in the chamber 4 between the piston 20 and the partition wall via the inlet hole 13 and hole 43a in the liner. As the piston 19 describes the forward stroke along with the fingers, the fingers will slide into and engage in the apertures 37a and 37b and 37c and 37d in the channels 36 in the slides 24 and 25 at corresponding one ends of the slides thereby engaging the slides onto the fingers. The tapered ends of the fingers will facilitate minimal contact between the fingers and the slides so as to reduce friction between the fingers and slides during sliding of the fingers against the slides and ensure smooth sliding movement of the fingers against the slides. The tapered ends of the fingers will also facilitate the fingers to slide into the apertures in the slides. As the piston 19 moves forward further, the slides will also move with the piston 19 until inlet port 9 is
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misaligned with hole 26 in slide 24, inlet port 10 is aligned with hole 27 in slide 24 , outlet port 11 is aligned with hole 28 in slide 25 and outlet port 12 is misaligned with hole 29 in slide 25. Inflow of water into the space in the chamber 3 between the piston 19 and end cover
6 via the inlet port 9 and outflow of water in the space in the
chamber 3 between the partition wall 5 and the piston 19 into the
underground tank via outlet port 12 are discontinued. Forward stroke of
piston 19 and slides 24 . and 25 comes to an end. Simultaneously
forward stroke of the piston 20 also comes to an end. Pumping of
water in the space in the chamber 4 between piston 20 and end cover
7 into the overhead tank via holes 43d and 16 and suction of water
into the space in the chamber 4 between the piston 20 and partition wall
5 via holes 13 and 43a are also discontinued. At this time, the
relative positions of the pistons 19 and 20 in the chambers 3 and 4
and the slides in the chamber 3 are as shown in Fig 2 and the pistons
and the slides are ready to describe the reverse strokes. In chamber 4,
inlet hole 13 is closed and inlet hole 14 is opened and outlet hole 15 is
opened and outlet hole 16 is closed by the respective valves 47a and
47b and 48a and 48b. Water flows into chamber 3 in the space
between piston 19 and partition wall 5 and develops a positive pressure
against piston 19. Due to the pressure of water being developed in the
space in the chamber 3 between the piston 19 and the partition wall 5,
the piston 19 describes the reverse stroke in the direction of the end
cover 6. As the piston 19 moves in the direction of the end cover 6,
water in the space in the chamber 3 between the end cover 6 and
piston 19 is forced out into the underground tank via hole 28 in slide
25 and outlet port 11. As the piston 19 moves in the direction of the
end cover 6, piston 20 also describes the reverse stroke and moves in
the direction of the partition wall. Water in the chamber 4 in the
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space between the piston 20 and the partition wall 5 is pressurised and forced out into the overhead tank via the hole 43 c in the liner 42 and corresponding outlet hole 15. Water is also sucked into the space in the chamber 4 between the piston 20 and end cover 7 via inlet 14 and corresponding hole 43b in the liner 42 due to suction being created in the space in the chamber 4 between the piston 20 and end cover 7. During reverse stroke of the piston 19, the fingers disengage from the apertures 37a, 37b and 37c and 37d in the channels of the slides at the said one ends of the slides and move with the piston 19 in the reverse direction. As the other ends of the fingers are tapered, they slide out of the apertures very gently. The fingers slide in the channels of the slides and move with the piston 19 in the direction of the end cover 6. The fingers slide in the channels of the slides until they slide into the apertures 37a, 37b and 37c and 37d at the corresponding other ends of the slides and engage onto the slides. On being engaged onto the fingers, the slides start sliding and moving with the piston 19 in the direction of the end cover 6. The slides describe the reverse stroke with the piston 19 in the chamber 3 until inlet port 10 and hole 27 in the slide 24 and outlet port 11 and hole 28 in the slide 25 are misaligned and inlet port 9 and hole 26 in the slide 24 and outlet port 12 and hole 29 in the slide 25 are aligned. Flow of water into the space in the chamber 3 between piston 19 and partition wall 5 via inlet port 10 and outflow of water into the underground tank via outlet port 11 are discontinued. Reverse stroke of piston 19 comes to an end. Reverse stroke of piston 20 also comes to an end. Out flow of water in the space in the chamber 4 between the piston 20 and partition wall 5 via outlet hole 15 and corresponding hole 43c in the liner 42 into the overhead tank and suction of water into the space in the chamber 4 between the piston 20 and end cover 27 via the inlet hole 14 and
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corresponding hole 43b in the liner 42 are discontinued. The pump is now ready for the next cycle of operation as shown in Fig 1. Thus water flows alternately into the underground tank and into the overhead tank from chambers 3 and 4 so as to ensure continuous supply of water into the underground tank and overhead tank until the inflow of water from supply line 45 lasts. While the piston 19 is describing the forward stroke and until the other ends of the fingers 30 and 31 engage onto the slides and the slides also start describing the forward stroke with the piston 19, the slides are retained in position by the outer balls 39 protruding into the corresponding aperture 37a or 37b and 37c or 37d in the slides at respective ends thereof. When the slides move forward with the piston 19 the slides disengage from the spring biased balls 39. At the end of the forward stroke of the slides, the spring biased inner balls 38 protrude into the respective apertures 37a oe 37b and 37c or 37d in the slides and retain the slides in position. Similarly while the piston 19 is describing the reverse stroke and until the other ends of the fingers 30 and 31 engage onto the slides and the slides also start describing the reverse stroke with the piston 19, the slides are retained in position by the inner balls 38 protruding into the corresponding apertures 37a or 37b and 37c or 37d in the slides at the respective ends thereof. When the slides move back with the piston 19 the slides disengage from the spring biased inner balls 38. At the end of the reverse stroke of the slides, the spring biased outer balls 39 protrude into the respective apertures 37a or 37b and 37c or 37d in the slides and retain the slides in position.
According to the invention the pump operates under the influence of the pressure of the incoming water from the supply line without using any external energy input. Therefore, the pressure available in the incoming
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water is fully utilised without being wasted. The pump of the invention does not require any control circuit and is cost effective and simple in construction. The output pressure of the pump ie the pressure available for pumping water from the chamber 4 into the overhead tank can be varied in a given construction of the pump by replacing the replaceable liner and the piston 20 so as to create varying volume within the chamber 4 and varying volume ratio between chambers 3 and 4. The liner is, however, optional and the pump can work without the liner. The output pressure will obviously depend upon the volume ratio of the chambers 3 and 4. The larger the volume ratio the higher the output pressure. Once the incoming water in the supply line has completely stopped the water in the underground tank is lifted into the overhead tank by operating the electric pump. The pump of the invention can be effectively used as a booster or auxiliary pump to the electric pump so as to reduce the energy consumption of the electric pump and save cost. Additionally, in case of break down of the electric pump, the pump of the invention will ensure lifting of certain amount of water into the overhead tank so as to ensure water distribution at the utility points atleast for some time until the electric pump is repaired.
Using a typical pump of the invention comprising chambers 3 and 4 with a volume ratio 2:1 and an incoming water of pressure of 1.5 Kg/ sq cm it was possible to increase the pressure of the outflowing water to 3 kg/ sq cm. The outflowing water at this output pressure can be easily lifted to a height of 20 to 25 meters.
The detachable end covers will facilitate easy access into the housing for cleaning or replacement of the liner, slides or the like. Instead of two independent slides, the slide can be single piece in the form of a
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hollow cylinder corresponding to the inner diameter of the housing. The housing can be square, rectangular, triangular or elliptical in crosssection besides being circular. The valve mechanism can be of a different configuration or construction. The objective of the invention is essentially to make effective use of the energy available in the incoming water. Instead of water, other liquids or fluids can also be used for driving the pump of the invention. Essentially the pump is for increasing the pressure output. Instead of lifting the water into overhead tanks, it can also be used for lifting the water to a higher level or driving a load like an actuator. The mounting bases are optional and may be of different construction / configuration. The pump can remain in position under its own weight without the mounting means. Such variations of the invention are to be construed and understood to be within the scope of the invention.
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We claim:
1. A self driven reciprocating type water pump located on an underground water tank and comprising a housing provided with mounting means for mounting it on the underground tank and partitioned into two chambers by a partition wall across the length thereof, one chamber being larger in volume than the other chamber and provided with a pair of inlet ports and a pair of outlet ports, the inlet ports and outlet ports being equally spaced apart along the length of the said one chamber and being located directly opposite to one another, the inlet ports being connected to an incoming water supply through a valve, the outlet ports being connected to the underground tank, the other chamber being provided with a pair of inlet holes and a pair of outlet holes, the inlet holes and outlet holes being equally spaced apart along the length of the said other chamber and being directly opposite to one another, the inlet holes each being connected to the underground water tank through a non-return valve, the outlet holes each being connected to an overhead tank through a non-return valve, the spacing between the inlet holes and outlet holes corresponding to the spacing between the inlet ports and outlet ports, a piston rod reciprocally disposed in the partition wall leak tight and extending into the said one and the other chambers, the piston rod comprising a piston fitted at each end thereof, one piston being located in the said one chamber and the other piston being located in the said other chamber and a valve mechanism for closing and opening alternately diagonally opposite inlet ports and outlet ports during the forward and reverse strokes of the respective piston, the volume ratio between the one chamber and the other chamber being selected to increase the output pressure of the pump.
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2. A water pump as claimed in claim 1, wherein the valve mechanism comprises a pair of directly oppositely disposed slides, one slide being located along the inner surface of the said one chamber against the inlet ports and provided with a pair of spaced apart holes along the same line as the inlet ports and the other slide being located along the inner surface of the said one chamber against the outlet ports and provided with a pair of spaced apart holes along the same line as the outlet ports, the distance between the holes in the said one slide being equal to the distance between the inlet ports and outlet ports in the said one chamber and the distance between the holes in the said other slide being more than the distance between the holes in the said one slide by twice the stroke of the slides in the said one chamber such that the holes in the slides are offset with respect to one another and diagonally opposite inlet ports and outlet ports are closed and opened by the slides alternately during the forward and reverse strokes of the piston in the said one chamber , sliding means for sliding the slides forward and back with the respective piston and retainer means for retaining the slides in position.
3. A water pump as claimed in claim 2, wherein the sliding means comprises a pair of fingers associated with each of the slides, the fingers being disposed at opposite sides of the piston in the said one chamber leaf spring biased against the respective sides of the piston, one ends of the fingers being pivoted at the opposite sides of the piston in the said one chamber and the other ends of the fingers being tapered and slidably located in a pair of channels formed along the length of the respective slide adapted to slide into a pair of directly opposite apertures provided at each end of the slides, the apertures in the slides being as equidistantly located as the inlet ports in the said one
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chamber and the slide retaining means comprises a pair of balls associated with each of the slides, the balls being disposed in tandem compression spring biased against one end of each of the slides along the length thereof and protruding into one of the apertures in the slides one after the other so as to retain the slide in position, the distance between the balls corresponding to the stroke of the slides.
4. A water pump as claimed in anyone of claims 1 to 3, wherein the housing comprises detachable end covers.
5. A water pump as claimed in anyone of claim 1 to 4, wherein the housing is square, rectangular, triangular or elliptical.
6. A water pump as claimed in anyone of claims 1 to 5, wherein the said other chamber comprises a replaceable liner located therein and provided with holes corresponding to the inlet holes and outlet holes in the said other chamber.
Dated this 29th day of March 2007

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ABSTRACT
A self driven reciprocating type water pump (1) located on an underground water tank. The pump comprises a housing (2) provided with mounting means (2a, 2b) for mounting it on the underground tank and partitioned into two chambers (3, 4) by a partition wall (5) across the length thereof. One chamber (3) is larger in volume than the other chamber (4) and is provided with a pair of inlet ports (9, 10) and a pair of outlet ports (11, 12). The inlet ports and outlet ports are equally spaced apart along the length of the said one chamber and are located directly opposite to one another. The inlet ports are connected to an incoming water supply through a valve. The outlet ports are connected to the underground tank. The other chamber is provided with a pair of inlet holes (13, 14) and a pair of outlet holes (15, 16). The inlet holes and outlet holes are equally spaced apart along the length of the said other chamber and are directly opposite to one another. The inlet holes are connected to the underground water tank through non-return valves. The outlet holes are connected to an overhead tank through non-return valves. The spacing between the inlet holes and outlet holes correspond to the spacing between the inlet ports and outlet ports. A piston rod (17) is reciprocally disposed in the partition wall leak tight and extend into the said one and the other chambers. The piston rod comprises a piston (19, 20) fitted at each end thereof. One piston (19) is located in the said one chamber and the other piston (20) is located in the said other chamber. A valve mechanism (24, 25) is provided for closing and opening alternately diagonally opposite inlet ports and outlet ports during the forward and reverse strokes of the respective piston. The volume ratio between the one chamber and the other chamber is selected to increase the output pressure of the pump (Fig 1).