GB2235719A

GB2235719A - Augmented water supply system

Info

Publication number: GB2235719A
Application number: GB9018889A
Authority: GB
Inventors: George Ernest Dunning
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-09-05
Filing date: 1990-08-30
Publication date: 1991-03-13
Anticipated expiration: 2010-08-30
Also published as: GB9018889D0; GB2235719B

Abstract

A system for augmenting a water supply with rainwater includes a cistern (2) mounted at the inlet of a rainwater downpipe. The downpipe extends from towards the top of the cistern (2) so that the cistern (2) holds a predetermined head of water. A submersible pump (5) is positioned within the cistern (2) and arranged to pump water from the cistern (2) to a reservoir tank (12). A control circuit is automatically responsive to levels in the cistern (2) and in the reservoir tank (12) and switches the submersible pump (5) ON when the water in the cistern (2) rises to a first predetermined level, and turns the pump OFF when the water in reservoir tank (12) rises to a second predetermined level. <IMAGE>

Description

AUGMENTED WATER SUPPLY SYSTEM The present invention relates to a system for collecting rainwater from the roofs of buildings and directing it into a reservoir tank within the building where it may be used, for example, to supplement the existing mains water supply.

It is desirable to economise in the consumption of water for domestic use by exploiting sources of water other than the mains water supply. Rainwater is a natural asset which normally flows to waste and which might be used for this purpose.

According to the present invention, a system for augmenting a water supply with rainwater comprises a cistern arranged to be mounted between the outlet of a gutter and the inlet of a rainwater downpipe, the inlet of the rainwater downpipe extending from towards the top of the cistern so that the cistern holds a predetermined head of water, a submersible pump positioned within the cistern and arranged to pump water from the cistern to a reservoir tank, and control means automatically responsive to water levels in the cistern and in the reservoir tank and arranged to switch the submersible pump ON when the rainwater in the cistern rises to a first predetermined level, and to turn the pump OFF when the water in the reservoir tank rises to a second predetermined level.

The present invention provides a system which can be incorporated into the guttering system of a house to collect rainwater in such a way that it can be integrated with the primary water supply and made available for use in the house. The system would typically be located within the short section of rainwater downpipe known as the swan-neck which extends between the eaves of a roof and unites the gutter with the downpipe running close to the wall. The cistern collects all the water leaving the gutter. When the water within the cistern has risen to a predetermined level it is then automatically pumped to the main reservoir tank. All water above that necessary to fill the cistern to a predetermined head overflows into the rainwater downpipe for disposal in the usual fashion.

The pump preferably includes a filter for the rainwater. With an appropriately fine filter the water from the cistern may be used to provide drinking water.

Alternatively the water may be used solely for the flushing of a water closet, in which case less stringent filtering is required.

Preferably the control means include a float switch in a control circuit for the pump, the switch being fixed at a predetermined level within the cistern. Preferably the float switch is incorporated within a separate slow-draining chamber within the cistern.

As described in further detail below, the control system may advantageously use float switches. It is found to be particularly advantageous to incorporate the float switch in the cistern within a separate slow-draining chamber so as effectively to increase the hysteresis of the control system.

Preferably the cistern includes means for automatically flushing the cistern when the water within the cistern rises above a predetermined head. Preferably the means for flushing include a siphonic outlet arranged to drain water from towards the bottom of the cistern when the predetermined head is exceeded.

Alternatively, or additionally, the means for automatically flushing the cistern may comprise a valved outlet automatically responsive to the control means to open and drain the cistern when the predetermined head is exceeded. In this case preferably the valve is an electrically operated valve incorporated in the seal between the downpipe and the base of the cistern.

Preferably the control means include a further float switch set at a level corresponding to the said predetermined head. The further float switch may be mounted in the reservpir tank. Alternatively the further float switch may be mounted in the cistern at a level between the head of the siphonic outlet and the inlet to the downwater pipe.

Preferably one or more auxiliary cisterns are connected siphonically to the cistern including the submersible pump.

Preferably the reservoir tank includes means for supplementing the water in the reservoir tank with water from the mains water supply when there is insufficient water in the cistern to fill the reservoir tank.

One example of a system in accordance with the present invention will now be described in detail with reference to the accompanying drawings in which: Figure 1 shows a front view of the cistern with the front face of the cistern removed so as to expose the contents, in place beneath the gutter; Figure 2 showns a side view of the cistern in place beneath the gutter; Figure 3 shows a plan view of the cistern and contents; Figure 4 is a diagram of the specific wire connections between components employed in the rainwater transference system; Figure 5 illustrates the installation of the complete system; Figure 6 illustrates an ancillary installation which features an automatic flushing system; and Figure 7 illustrates a modified automatic flushing system.

Referring to the drawing Figure 1 the rainwater pipe which normally joins the gutter to the downpipe is here shown 1 cut short and turned slightly so as to direct the rainwater into the cistern 2. A bracket fixed to the gutter-board holds this sort length of pipe in place.

The cistern is supported close to the wall and under the eaves by a wall-bracket and a catch 14 and also by virtue of the union 3 sealed into the base which joins into the normal downpipe. Inside the cistern a length of pipe 4 fits into the top of the union and extends to a height slightly below the top rim. A ssrain-cock is provided in the base 15 to facilitate the flushing out of any debris which may accumulate. Within the cistern lies the submersible electric pump 5. This has filter 6 at its inlet and its outlet is connected to a flexible tube 7 which passes up through the eaves into the roof space.

The operation of the pump is controlled by a 'float-switch' 8A contained within a separate chamber 9.

This switch consists of a magnet sealed inside a float which is pivoted so as to actuate a reed-switch contained inside the fixed body of the outer case. The float-switch is shown in Figure 1 in the OFF position.

When immersed in water the pivoted float will rise until it is in line with the metal projection conveying flux to the reed and causing it to change to the ON position. If the whole float switch is inverted then the ON-OFF action is reversed. The object of the separate chamber 9 is to extend the natural hysteresis of the float switch 8A so as to match it with the average rate of rainfall during pumping. This action will be explained more fully later.

Referring back to Figure 1, a strap 10 is shown set diagonally across the corner of the cistern. This is to hold the siphon-tube 11 in position within the pocket 16 which retains water when the cistern is drained.

Referring to Figure 5, the master cistern 2 is shown on the left and the slave cistern 2A on the right joined by the siphon-tube 11 supported by rings screwed into the eaves. The output from the pump flows along the tube 7 to connect with the reservoir tank 12 here illustrated with the front side removed to expose the ball-valve 13.

The setting of the ball valve is arranged so as to keep the level of main supply water at a minimum height. A water float-switch 8B mounted in the inverted mode is shown sited near to the top of the reservoir so that it switches OFF when the water level reaches maximum height.

The reservoir tank is here shown as serving a WC only but other conveniences may also be connected in the normal manner.

The operation of the system will now be described with reference to the diagram shown at Figure 4.

When rainwater enters the system initially, the pump is not energised and the level within the cistern rises to cover the pump completely. It also enters the small chamber enclosing the float-switch 8A via a hole near to its base and also from over the top if the rainwater level rises rapidly. This will eventually cause the float of the float-switch to rise and close the switch to the ON position. Assuming the reservoir tank is not full, then the float-switch 8B will be in the ON position as shown in the diagram and current will flow to energise the relay, causing its contacts to close and in turn the pump will start. If the rate of pumping is faster than the rate of rainwater entering the cistern then the level of water will fall.Now the water held within the chamber can only empty by means of the small hole at its base and this will cause its level to lag behind that of the rest of the water in the cistern which will tend to keep the float-switch 8A ON longer. This enables the pump to deal with its full head of water before being turned off and also helps it to cope with the wide variations in the rate of rainwater entering the cistern.

The normal hysteresis of ON-OFF positions for the switch is effectively magnified by means of the lag in discharge rate of water from the chamber and also modified in accordance with the rate of water entering the cistern.

When the reservoir tank is full to maximum capacity the float of the float-switch 8B will have risen sufficiently from the horizontal position for it to switch OFF. This will disconnect the flow of current from energising the relay causing its contact points to remain open and effectively closing down the pump. If thereafter the water level in the cistern continues to rise with the pump closed down or if the rainfall is so intense that the pump cannot cope, then the extra head of water will flow into the top of the downpipe which is within the cistern and run to waste in the normal manner or initiate a flushing action which will be described later.If there is insufficient rainfall to augment the main supply, then the water level within the reservoir tank will fall until a minimum height is reached when the ball-cock will open up the main water supply so as to maintain the services in the normal manner.

Referring to Figure 6 a particular method for joining a rainwater-butt into the system is illustrated.

This not only enables the collecting barrel to be located remotely when direct siting below the downpipe is inconvenient, but it also bestows the benefit of an automatic flush to the cistern when rainfall is excessive or when the pump is closed down. For connection of the pipe 17 a union is formed in the side of the cistern 2 at a height more than half way up the cistern but below the level of the top of the downpipe. By having a vertical larger bore plastic pipe extending down inside the cistern towards the bottom of the cistern an outlet is provided which overcomes the tendency to blockage which would otherwise be encountered with a flushing outlet pipe extending directly from the base of the cistern.

This pipe then passed around the grooved disc which is adjacent to the cistern and is fixed to the wall at a height such that the top of the flexible tube is level with the top of the downpipe within the cistern. This disc 18 has an eccentric mounting so as- to enable it to be adjusted. The tube then goes through a conduit 19 to pass into the cask 20 at ground level. Because the height of the flexible tube is above that of the float-switch within the cistern it does not interfere with the normal operation of the pump, but if the pump is closed down due to the reservoir tank being full, for example, then the rainwater level within the cistern will rise until the height of the tube is reached and it will then commence to siphon the water out of the cistern.

The siphoning action will continue until the cistern is drained and because the drop is considerable it will be fairly rapid so as to flush the cistern; particularly if it occurs during a downpour, as is usually the case.

The siphon tube 11 connecting with a slave cistern (not shown) remains active during the draining of the cistern by virtue of the pocket previously described which seals the ends of the tube.

Referring to Figure 5 an extra reservoir tank 21 is shown joined to reservoir tarry 12 by means of a siphon tube 22. This is to illustrate the ease with which added storage capacity is obtained by use of a siphon.

The preferred embodiment includes means by which silt will be flushed through the cistern during bouts of heavy rainfall; which is the periods during which most of it accumulates.

This may be by the attachment of a water-butt to the system by means of a siphon tube fed from the base of the cistern so that the cistern will automatically flush when rainfall becomes heavy, as described above.

An alternative flushing mechanism takes the form of a modification to the pipe which extends upward within the cistern so that it is of smaller diameter than the union into which it fits and slides easily within. A rubber or plastic skirt forms a seal with the base of the cistern, thus a plug is formed which may be raised to allow the passage of liquid and silt into the downpipe.

The raising or lowering of the plug or valve is effected by means of a solenoid attached to the cistern.

The operation of the flushing valve is as follows: Normally the valve remains seated as shown in Figure 1. The flexible skirt 23 forming a seal with the top of the union set in the base of the cistern. When the reservoir tank has been filled or alternatively when the head of water in the cistern reaches a specific height, the float switch 8C will close.

This will cause the solenoid 24 to energise and to raise the tube. This will probably be against a spring 25 needed to normally hold the pipe down during the rise of water which will make the tube buoyant. Thus a balance has to be set between the strength of the solenoid, the weight of the plug, the force of the spring and the buoyancy of the pipe, to avoid oscillation.

Large holes are cut into the -lower part of the tube 26 facilitate unobstructed flow through the base when the valve is raised whilst retaining the end part of the pipe as a guiding medium.

If the attachment of a water-butt is inconvenient then the flushing valve becomes mandatory and the siting of the controlling float-switch is preferably in the reservoir tank. On the other hand if the water-butt attachment is included but is not sufficiently effective in removing the silt during flushing then the flushing valve must be fitted and the siting of the controlling float-switch would have to be inside the cistern high enough to be above the level of the water-butt siphon but below the level of the top of the tube. Also it would have to be contained within a separate chamber which discharges into the main body of water through a restricting hole, as described above for control of the submersible pump.

Claims

1. A system for augmenting a water supply with rainwater comprising a cistern arranged to be mounted between the outlet of a gutter and the inlet of a rainwater downpipe, the inlet to the rainwater downpipe extending from towards the top of the cistern so that the cistern holds a predetermined head of water, a submersible pump positioned within the cistern and arranged to pump water from the cistern to a reservoir tank, and control means automatically responsive to water levels in the cistern and in the reservoir tank and arranged to switch the submersible pump ON when the rainwater in the cistern rises to a first predetermined level, and to turn the pump OFF when the water in the reservoir tank rises to a second predetermined level.

2. A system according to claim 1, in which the pump includes a filter for the rainwater.

3. A system according to claim 2, in which the control means include a float switch in a control circuit for the pump, the switch being fixed at a predetermined level within the cistern.

4. A system according to claim 3, in which the float switch is incorporated within a separate slow-draining chamber within the cistern.

5. A system according to any one of the preceding claims, in which the cistern includes means for automatically flushing the cistern when the water within the cistern rises above a predetermined head.

6. A system according to claim 5, in which the means for automatically flushing include a siphonic outlet arranged to drain water from towards the bottom of the cistern when a predetermined head is exceeded.

7. A system according to claim 5 or 6, in which the means for automatically flushing the cistern comprise a valved outlet automatically responsive to the control means to open and drain the cistern when the predetermined head is exceeded.

8. A system according to claim 7, in which the valved outlet is incorporated in the seal between the downpipe and the base of the cistern.

9. A system according to claim 7 or 8, in which the control means include a further float switch set at a level corresponding to the said predetermined head at which the means for automatically flushing are actuated.

10. A system according to claim 9, in which the further float switch is mounted in the reservoir tank.

11. A system according to claim 9, in which the further float switch is mounted in the cistern at a level between the head of the siphonic outlet and the inlet to the downwater pipe.

12. A system according to any one of the preceding claims, in which one or more auxiliary cisterns are connected siphonically to the cistern including the submersible pump.

13. A system according to any one of the preceding claims, in which the reservoir tank includes means for supplementing the water in the reservoir tank with water from the mains supply when there is insufficient water in the cistern to fill the reservoir tank.

14. A system according to any one of the preceding claims, in which the cistern is arranged to fit beneath the eaves of a building between the outlet of a gutter at that top of the rainwater downpipe.

15. A system according to claim 6, in which the siphonic outlet includes a union formed part way up a sidewall of the cistern and a pipe extending from the union inside the cistern towards the base of the cistern.

16. A system substantially as described with respect to the accompanying drawings.