GB2290114A - Pumping systems for liquids - Google Patents

Abstract

A system 1 for pumping water from a source 2 to a tank 3 comprises a solar panel 6, a pumping chamber 10 of variable volume having an inlet and outlet duct 8 and bladder 9 in a pivotally-mounted pressure vessel 7. The panel 6 employs hexane as a working fluid and is connected to pressure vessel 7 and a condenser 17 tiltable therewith. When hexane is vapourised in the panel 6 it causes bladder 9 to move from its Fig. 3 position to its Fig. 1 position expelling water from chamber 10 via the duct 8 to reservoir 31, counterweight 56 then causing tilting of the vessel 7 and condenser 17 and operation of valves 35 and 45. Should little or no water be drawn up duct 20 the pressure vessel 7, influenced by the counterweight 56, will remain in the tilt attitude shown. This acts as a safety means since the condenser 17 retains sufficient hexane as liquid to leave the panel 6 substantially empty of liquid. The system 1 may be used as a master pumping system to operate a slave pumping system (60, Figs. 4, 5). <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO PUMPING SYSTEMS FOR LIQUIDS BACKGROUND TO THE INVENTION This invention relates to pumping systems for liquids and is concerned with solar powered pumping systems for liquids.

Pumping systems according to the invention have particular application to the pumping of irrigating and/or drinking water from below ground level.

The most arid regions of the earth tend to have an abundance of solar energy as well as a substantial need to pump water from underground sources or depleted rivers. In such regions electrical power is seldom available; petrol and diesel fuels tend to be too expensive; machine maintenance operators scarce, and spare parts difficult to obtain.

SUMMARIES OF THE INVENTION According to a first aspect of the present invention, a pumping system for liquids comprises a solar energy collection means employing a working fluid which evaporates when raised in temperature and which condenses when lowered in temperature, a condenser for abstracting heat from the working fluid, a pumping chamber of variable volume having a fluid inlet and a fluid outlet, and displacer means for utilising expansion and contraction of the working fluid to vary the volume of the pumping chamber in a cyclic manner whereby liquid being pumped is passed through the pumping chamber by way of said inlet and said outlet, and safety means operable whereby the solar collection means is evacuated of working fluid in the liquid phase should pumping of the liquid be reduced substantially.

The invention enables evaporation and condensation of the working fluid to take place without the need of valves to control flow of the working fluid during its cycle of operation According to another aspect of the present invention, a pumping system according to the preceding paragraph is operable as a master pumping system and is combined with a slave pumping system operable whereby the pumped output of the master pumping system is used to promote operation of the slave pumping system.

The safety means preferably comprise mounting the condenser so that it is tilted in order to drain and retain working fluid in the liquid phase from the solar collection means should pumping of the liquid be reduced substantially.

According to a second aspect of the present invention, a pumping system comprises two bellows, namely a pumping bellows having an inlet and an outlet, and an actuating bellows operable in a cyclic manner by pressurised fluid so as to vary the internal volume of the pumping bellows also in a cyclic manner, whereby pumping takes place, the two bellows being interconnected.

Such a pumping system may be manually operated.

Interconnection of the two bellows is preferably by means of an actuating member.

According to yet another aspect of the present invention, a pumping system according to the first said aspect is operable as a master pumping system and is combined with a slave pumping system comprising the second said aspect operable whereby the pumped output of the first aspect water pumping system is used to promote operation of the slave pumping system of the second aspect.

BRIEF DESCRIPTION OF THE DRAWINGS The various aspects of the present invention will now be described by way of example only, with reference to the accompanying semi diagrammatic drawings, wherein: Figure 1 is a side view of a pumping system according to the first aspect of the invention, Figure 2 is a plan view of the system, Figure 3 is a side view which illustrates the pumping system of Figure 1, but in a different mode, Figure 4 is a side view which illustrates the second aspect of the invention, and Figure 5 is a side view which illustrates a modification thereof.

DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENTS Figure 1 shows a pumping system 1 for use in pumping water from an underground source 2 to a collecting tank 3 disposed above ground level 4.

The pumping system 1 comprises a solar energy collection means 5 in the form of a solar panel 6 (Figure 2), pumping chamber 10 of variable volume having a common water inlet and outlet duct 8, and internal displacer means in the form of a flexible diaphragm or bladder 9.

The solar energy collection means 5 employs a working fluid which evaporates (expands) when raised in temperature by the supply of heat, and which condenses (contracts) when lowered in temperature by the removal of heat. The preferred working fluid comprises a hydrocarbon compound such as hexane, or a CFC refrigerant.

In this embodiment the working fluid is hexane.

The hexane is utilised by the bladder 9 to vary the volume of the pumping chamber 10 in a cyclic manner whereby water being pumped is passed through the pumping chamber 10 by way of the common inlet and outlet duct 8.

Safety means 15 described hereinafter are provided. The safety means 15 are operable whereby the solar panel 6 is evacuated of hexane in the liquid phase should pumping of the water cease or be reduced substantially.

The solar panel 6, which may be provided with a glazed cover in order to increase heat gain, has internal flow channels connected, by way of a riser duct 16, to the interior 18 of the bladder 9, which is disposed within a pressure vessel 7, and which is sealed to the inner wall thereof.

The interiors of the solar panel 6, the duct 16, the bladder 9 and a condenser 17 are, after evacuation of air present, charged with sufficient hexane working fluid to enable the system to operate.

The bladder interior 18 is connected to the riser duct 16 by a flexible joint 19 of bellows form and to the interior of the condenser 17 by a duct 21.

The underground source 2 is connected to the inlet/outlet duct 8 by a draw-off duct 20, the lower end of which incorporates a non-return valve 25.

The inlet/outlet duct 8 is also connected to a discharge duct 26 which incorporates a non-return valve 27. The duct 26 discharges pumped water into a tank-like reservoir 28 mounted on a rigid frame structure 29, which rests on the ground 4. Water enters the reservoir 28 by way of an upper opening 31.

The reservoir 28 has a water outlet duct 30 with a flow control valve 35 disposed therein.

The condenser 17 comprises a central duct 36 with blind-ended, stub-like extensions 37, extending outwardly therefrom. The condenser 17 is disposed within a condensing chamber 38, having a water inlet 39 and a water outlet 40.

The outlet 40, which incorporates a shut-off valve 45, is connected to the tank 3 by a duct 46.

The central duct 36 of the condenser 17, which is connected to the duct 21, is flexibly sealed to the condensing chamber 38 by a boot seal 47. The chamber 38 is mounted on the frame structure 29, and is disposed beneath the reservoir 28.

The pressure vessel 7 is mounted on a support structure 48, which is mounted in turn on the frame structure 29, but in a pivotable manner, by way of a pair of laterally-spaced brackets 49 and a pivot shaft 50 extending between the brackets 49.

The pressure vessel 7 can thus pivot freely relative to the supporting frame structure 29. The seals 19 and 47, plus a flexible joint 55 incorporated in the draw-off duct 20, allow this free movement.

A counterweight 56 is carried by the pressure vessel 7.

The valves 31 and 46 are interconnected and are operated together by means, not shown, sensitive to pivotable movement of the pressure vessel support structure 48.

With additional reference to Figure 3, assume the pressure vessel 7 inclined to the left, as shown in that figure.

Liquid hexane present in the solar panel 6 absorbs heat from solar energy collected by the panel and consequently evaporates, thus substantially increasing its volume.

The pressurised hexane, now in gaseous form, enters the interior 18 of the bladder 9, so as to displace it upwardly.

Bladder displacement causes water present in the pumping chamber 10 to be expelled therefrom (see Figure 1) through the common inlet/outlet duct 8, and into duct 26, opening non-return valve 27 as it does so.

Backflow along duct 20 is prevented by the non-return valve 25.

Water discharged by the duct 26 enters the reservoir 28, by way of reservoir opening 31. Water is prevented from leaving the reservoir 28, by means of the valve 35, which is in the closed position.

Some hexane gas enters the condenser 17 as well as the bladder interior 18 during this part of the operational cycle of the pumping system 1.

Expelling water from the pumping chamber 10 allows the pressure vessel counterweight 56 to come into operation whereby the pressure vessel 7 is tilted to the right, as shown in Figure 1.

At the same time valve 35 is opened and valve 45 is closed by this pivotal movement.

Water now enters the condenser chamber 38, so as to substantially fill it. The presence of the water on the exterior of the condenser 17 condenses the hexane gas therein, whereupon pressure drops in the bladder interior 18, ducts 16 and 21, and the interior of solar panel 6.

The drop in pressure results in downward displacement of the bladder 9, which causes water to be drawn up the duct 20 and into the pumping chamber 10. The pressure vessel 7 then reverts, by pivotal movement, to the position shown in Figure 3, overcoming the effect of the counterweight 56.

This pivotal movement causes valve 35 to be closed and valve 45 to be opened. Water then flows out of the condensing chamber 38 and into the collecting tank 3.

The cycle is then repeated.

The relative positions of the pivot shaft 50 and counterweight 56 are such that pivotal movement of the pressure vessel takes place as described.

With reference once more to Figure 1, should for any reason pumping cease or reduce to such a level whereby little or no water is drawn up duct 20, caused, for example by the source 2 drying up, bladder 9 will be in its upward position, and the pressure vessel 7, influenced by the counterweight 56, will assume the tilt attitude shown.

This results in the safety means 15 coming into operation. As the pressure vessel 7 is tilted to the right, as shown in Figure 1, the condenser 17 is tilted downwardly, also as shown. Thus the condenser 17 is placed in a position whereby it can collect and retain sufficient working fluid, ie hexane in liquid form, so as to leave the solar panel 6 substantially empty of liquid.

It will be appreciated that, as liquid hexane has been thus evacuated from the solar panel 6, further evaporation of the hexane is substantially prevented. Any rise in internal pressure that may take place will not exceed safety limits.

Any water present in the condensing chamber 38 will, by condensing action, add to the effect of the tilted condenser 17.

The safety means 15 comprise the tiltable condenser 17 and the duct 21, which serves as a self-drain conduit to the condenser.

The pumping system 1 enables evaporation and condensation of the working fluid to take place without need of valves to control the operating cycle of the working fluid.

The pumping system 1 also ensures that the solar panel 6 is evacuated of working fluid in the liquid phase during condensing of the working fluid, so reducing mechanical complication and improving reliability.

The pumping system 1 further avoids return by gravity of cooled condensate from the condenser 17 to the solar panel 6 which would otherwise re-heat, expand to a gas and return to the condenser.

This would ta) extend the time required for condensing and (b) cool the solar panel which would prevent the storage of solar generated heat during the condensing sequence of the cycle.

Although the pumping system 1 has no valves to control the working fluid circuit, it has the inherent ability of attaining a quiescent mode when sunlight is not available. This mode is such to ensure automatic start-up when sunlight is again available.

The embodiment of Figures 1 to 3 is concerned with a pumping system wherein water is lifted from a source 2 by the application of suction to the water being pumped or reduction in pressure of the displacement fluid.

Figure 4 illustrates an arrangement wherein a positive pressure pumping system 60 is used to draw water from a deeper underground source 61.

The system 60 may be disposed above the water level of the deep source 61, as shown in Figure 4, or it may be immersed in the source 61.

The pumping system 60 comprises two water-filled axially extendable bellows 63, 64, mounted on a restraining frame 65. The lower ends of bellows 63, 64, are fixed to the frame 65. The opposite or free end of the bellows 63 is interconnected, by way of an actuating rod 66, to the opposite or free end of bellows 64.

The restraining frame 65 is of box-like form and defines a chamber 67.

Bellows 63 is an actuating bellows and is superimposed on bellows 64. Bellows 64 is a pumping bellows, the interior of which provides a subsidiary pumping chamber of variable volume.

The actuating rod 66 extends between plates 68, 69 at the remote ends of the bellows 63, 64, and is slidable within a seal 70 separating the two bellows.

The pumping system 60 may be viewed as a slave pumping system and the pumping system 1 (Figures 1 to 3) may now be viewed as a master pumping system which controls the system 60 so as to promote operation thereof.

The interior of the actuating bellows 63 is connected, by way of a duct 75, to the duct 8 of the pressure vessel 7. The duct 75 incorporates a flexible joint 76 of bellows form.

The interior of the pumping bellows 64 is connected by a duct 77 incorporating a non-return valve 78, to the underground water source 61. The interior of the bellows 64 is also connected, by way of a duct 79 incorporating a non-return valve 80, to a balancing header tank 85. The tank 85 has an overflow duct 86 which discharges to the reservoir tank 28 of the pumping system 1. The duct 79 has a branch connection 87, disposed upstream of the non-return valve 80, to the interior of the chamber 67 which houses the bellows 63.

In operation,as the pumping system 1 operates as aforesaid, pressurised water from the duct 75 flows into the interior of the actuating bellows 63, causing the bellows 63 to expand and the bellows 64 connected thereto to contract. Contraction of the bellows 64 causes water therein to be expelled from the interior of the bellows 64. first into the duct 79 and from thence to the header tank 85.

When the water level in the header tank 85 reaches the overflow outlet thereof, the water flows into the reservoir 28 of the pumping system 1, to be employed as previously described, whereby the solar panel 6 is cooled.

This causes pressure in the duct 75 (Figure 2) to fall, whereupon the bellows 63 contracts, lowering the actuating rod 66, and thus expanding the bellows 64.

The result is that water is drawn from the source 61 into the interior of the bellows 64, non-return valve 80 closing to prevent backflow of water into the bellows 64. However, backflow is allowed to take place by way of duct 87 and chamber 67, whereby a downwardly acting force is applied to the exterior of the bellows 63 This downwardly acting force assists in expanding the bellows 64.

The operating cycle is repeated as the working fluid in the pumping system 1 is heated and cooled.

The arrangement allows the slave or servo pumping system 60 to be disposed beneath the ground level 4. Positive pumping takes place over height 'H1' and is not, therefore, subject to the normal barometric limitation of approximately 28 feet (8.104 metres) when water is raised by suction. The height 'H2' is subject to barometric limitation.

In the modification illustrated by Figure 5, the pumping system 1 is replaced by a positive displacement, manually-operated, pumping system 90 illustrated hereby a bellows 91 actuated by a T-handle 92 and disposed within the header tank 85.

The 'master' pumping system 90 is disposed above ground. The slave or servo pumping system may be disposed below ground. In this example, a duct 86 discharges to collection tank 3 (see Figure 1).

Claims (21)

1. A pumping system for liquids comprising a solar energy collection means employing a working fluid which evaporates when raised in temperature and which condenses when lowered in temperature, a condenser for abstracting heat from the working fluid, a pumping chamber of variable volume having a fluid inlet and a fluid outlet, and displacer means for utilising expansion and contraction of the working fluid to vary the volume of the pumping chamber in a cyclic manner whereby liquid being pumped is passed through the pumping chamber by way of said inlet and said outlet, and safety means operable whereby the solar collection means is evacuated of working fluid in the liquid phase should pumping of the liquid be reduced substantially.

2. A pumping system as claimed in claim 1 wherein the safety means comprise mounting the condenser whereby it may be tilted in order to drain working fluid in the liquid phase from the solar energy collection means and retain the same.

3. A pumping system as claimed in claim 1 or 2, wherein the displacer means comprise a flexible diaphragm disposed within a pressure vessel, so as to define a pumping chamber therewith.

4. A pumping system as claimed in claim 3 wherein the pressure vessel is pivotably mounted on a support structure.

5. A pumping system as claimed in claim 4 wherein the condenser is connected to the pressure vessel so as to pivot therewith.

6. A pumping system as claimed in claim 6 wherein the condenser is disposed within a condensing chamber and is movable relative thereto.

7. A pumping system as claimed in claim 6 wherein means are provided to admit coolant to and to allow said coolant to flow from, the condensing chamber in a cyclic manner.

8. A pumping system as claimed in claim 7 wherein said means comprise valve means operable by pivotal movement of the pressure vessel.

9. A pumping system as claimed in claim 7 or 8 wherein said coolant comprises liquid being pumped by said system.

10. A pumping system as claimed in claim 9 provided with a liquid storage reservoir for receiving the pumped liquid output and valve means operable to release stored liquid so that it flows into the condensing chamber when condensing of working fluid is required.

11. A pumping system as claimed in claim 10 provided with valve means operable to retain pumped liquid in the condensing chamber until condensation of the working fluid takes place.

12. A pumping system as claimed in any one of claims 4 to 11 wherein the solar collection means and pressure vessel are interconnected by means of a flexible joint.

13. A pumping system as claimed in any one of claims 1 to 12 operable as a master pumping system and combined with a slave pumping system operable whereby the pumped output of the master pumping system is used to promote operation of the slave pumping system.

14. The combination of claim 13 wherein the slave pumping system comprises at least one subsidiary pumping chamber of variable volume, and actuating means operable by said pumped output so as to vary the volume of said pumping chamber and thus promote the flow of liquid therethrough.

15. The combination of claim 14 wherein the subsidiary pumping chamber and the actuating means each comprise bellows.

16. A pumping system comprising two bellows, namely a pumping bellows having an inlet and an outlet, and an actuating bellows operable in a cyclic manner by pressurised fluid so as to vary the internal volume of the pumping bellows also in a cyclic manner, whereby pumping takes place, the two bellows being interconnected.

17. A pumping system as claimed in claim 16 wherein the two bellows are interconnected by an actuating member.

18. A pumping system as claimed in claim 17 wherein one bellows is superimposed on the other bellows and the actuating member interconnects the remote ends of the two bellows.

19. A pumping system as claimed in claim 18 wherein the actuating member comprises a rod slidably mounted on a seal separating the two bellows.

20. A pumping system as claimed in any one of claims 16 to 19 wherein the actuating bellows is displaceable by manual operation.

21. A pumping system as claimed in claim 20 wherein the actuating bellows is displaceable by liquid disposed in a manually-actuated, third bellows.