GB2287499A - Break tank for water recycling system - Google Patents

Abstract

A break tank (24) for use in a water recycling system comprises a recycled water inlet (40, 42) through which rainwater, recycled bathwater and the like is pumped, for subsequent supply via an outlet (46) to water closet cisterns or other applications for which recycled water can be used, and a fresh water inlet (56, 60), with first control means such as a ballcock (54, 58) arranged to allow fresh water into the tank when a predetermined low level (80) is reached, so as to ensure that the outlet (46) is always submerged. The tank has an unrestricted overflow such as a slot (50), slightly above the normal maximum water level (76). <IMAGE>

Description

WATER RECYCLING APPARATUS The present invention relates to apparatus suitable for recycling wash water in a domestic environment.

In the average household approximately one third of water used is for flushing water closets. There is no necessity for such water to come directly from the mains water supply and waste water from sinks and baths and rinse water from dish and clothes washing machines could be used for such a purpose. In view of the rapidly rising costs of treating and supplying mains water for domestic consumption, and the fact that many properties now have a metered water supply it would be particularly desirable to provide a means by which domestic waste water could be recycled and used for flushing water closets. In order to provide a system which is acceptable to consumers it is important that an uninterrupted supply of water can be provided for flushing purposes. The system moreover must require a minimum of operator intervention.In order to provide an uninterrupted supply it is necessary to provide for the supply of recycled water to be supplemented by mains water in situations in which the supply of recycled water is inadequate for some reason. This may occur for instance if a large temporary increase in the demand for flushing water occurs. The supplementing with mains water must be achieved without operator intervention and in such a manner that there is no chance of contaminating the mains supply with any germs or other undesirable agents which may be present in the recycled water.

The object of the invention is to provide an apparatus which is suitable for incorporation in a waste water recycling system and which meets the above objectives.

Thus, according to the invention, there is provided a water recycling break tank apparatus including a tank, a recycled water inlet with a discharge aperture, an unrestricted overflow, a fresh water inlet with water level dependent first control means and a discharge aperture positioned above an invert level of the overflow and a recycled water supply outlet wherein the first control means is adapted to always maintain the supply outlet submerged.

The provision of an unrestricted overflow which may be in the form of a large aperture in the side of the tank or a weir region of reduced height in a tank side wall will ensure that recycled water in the tank will never have a level above the invert of the overflow. Positioning the fresh water discharge outlet above this invert level will accordingly prevent contamination of the fresh water. The use of a unrestricted overflow as opposed to a conventional piped overflow will eliminate the danger of overflow being prevented by blockage. Furthermore, the maintenance by the first control means of water level in the tank above the recycled water supply outlet will ensure that the tank will always be able to supply water for flushing purposes, regardless of the rate of supply of recycled water.

In order to keep any pump provided to supply the tank with recycled water in a primed condition preferably the first control means always maintains the recycled water discharge aperture submerged. In order that only little water need be present in the tank for this condition to be met, the recycled water discharge aperture is preferably located in a lower region of the tank and more preferably less than 20% of the tank's height from its bottom.

So as to reduce the amount of fresh water which flows into the tank during use, preferably the first control means allows fresh water to flow into the tank to maintain the recycled water discharge aperture submerged but prevents such flow when water in the tank is below its working level. More preferably, such flow prevention occurs when the depth of water in the tank is any more than 20% and preferably 10% of the tank's height. With such an arrangement demand for fresh water as a consequence of the lowering the level of water in the tank resulting from a single flush of a water closet can be completely avoided.

As the apparatus must be provided with an unrestricted overflow, (i.e. not a customary piped overflow) the apparatus preferably includes containment means such as a container in or above which the tank may be positioned which can act to collect overflow water and route it via a pipe to the exterior of a building in which the apparatus is located.

The tank may be supported above the container by a walled structure which can conveniently be used to accommodate and provide sound insulation for a pump connected to supply recycled water to the recycled water inlet discharge aperture. The pump may alternatively be located remotely from the tank and container.

In order to prevent the pump from rapidly on-off cycling or hunting the apparatus preferably includes second control means which causes the pump to start only when water in the tank is at a first low level and causes the pump to stop when water in the tank reaches a higher working level. The distance between these levels preferably represents at least 40% of the height of the tank so that in use a good circulation of water within the tank is brought about and the need for expensive chemical treatment of water in the tank can be avoided.

Conveniently the second control means includes a float, the weight of which causes the second control means to start the pump when water is at the first level and the buoyancy of which causes the second control means to stop the pump when water reaches the working level.

In order to prevent actuation of the pump in circumstances in which supply of recycled water is not available, the second control means preferably includes an over-ride system for preventing pump actuation if one or more conditions are not met. Such conditions may include inadequate water in a reservoir from which the pump is supplied or the temperature of water connections to the pump being at or below freezing point.

The invention also includes a water recycling system including the above apparatus in combination with ; recycled water reservoir located below the apparatus connected by a pipe to an inlet of the pump. Preferably a one-way valve is provided which prevents flow of water from the pump back into the reservoir so that the inlet of the pump remains flooded at all times.

The invention will now be described by way of example only with reference to the accompanying figures in which: FIG. 1 shows a schematic representation of a domestic water recycling system including apparatus according to the invention; FIG. 2 shows a partly schematic vertical section through the water recycling break tank apparatus shown in Fig. 1; FIG. 3 shows a horizontal section on the line C-C of the apparatus shown in Fig. 2; and FIG. 4 is a diagrammatic representation of features of the control means controlling the pump.

Figure 1 shows a schematic representation of a waste water recycling system installed in a typical house.

Waste water 1 from a bath 2 and a sink 4 is routed via pipes 6 to a reservoir 8 through a filter 9. Rain water from guttering 10 is also led to the reservoir via downpipe 12. Pumped rinse water from dish and clothes washing machines may also be routed to the reservoir.

Should the reservoir become full, overflow via overflow pipe 14 into a drain 16 occurs. This process will backwash the filter 9 washing particles lodged therein down the drain 16.

A pipe 18 extends from a location near the bottom of reservoir 8 to a water recycling break tank apparatus 22 located in a roof void of the house. At the lower end of the pipe 18 a one-way valve 20 is located which acts to prevent water passing from the pipe into the reservoir 8.

In a manner which will be described in more detail below with reference to Figure 2 waste water is distributed from the apparatus 22 via pipes 24 and 26 to water closet cisterns 28 and 30 respectively.

The apparatus includes a square tank 24 supported by walled support structure 26 located in an open square container or bund 28. In the centre of the container 28 a square mount 30 is provided to the top of which a selfbleeding centrifugal pump 32 is connected which is driven by a commutator motor 34. A horizontal cross-section of the container 28, mount 30 and support structure 26 on the line C-C in Figure 1 is shown in Figure 3.

The pipe 18, the lower end of which is positioned in the reservoir 8, passes through a first aperture 36 in the support structure 26 and is connected to an inlet of the pump 32. A second pipe 38, which is flexible, leads upwards from an outlet of the pump to a recycled water inlet fixture 40 having a discharge aperture 42 located close to the base of the tank 24.

A recycled water outlet fixture 46 is connected to the bottom of the tank 24 and leads into a third pipe 44 which passes through a second aperture 48 in the support structure and away from the apparatus. This third pipe 44 is connected to the pipes 24 and 26 discussed above which lead to the water closet cisterns.

In the side of the tank 24 near its upper edge 52 a large overflow slot 50 is provided.

On the left-hand side of the tank 24 as seen in Figure 2 a fresh water inlet 54 is provided with a discharge aperture 56 and an actuating float 58. The fresh water inlet is connected to the mains water supply by a pipe 60.

On the right-hand side of the tank 24 as seen in Figure 2 a float switch 62 is provided. The float switch 62 includes a depending rod 64 up and down which a weighted float 66 can travel between upper and lower stops 68 and 70. A switch actuating arm 72 is pivotally connected to the switch and is rotatably connected to the rod 64 adjacent one end and a counterweight 74 at its other end.

The operation of the water recycling break tank apparatus will now be described with particular reference to first, second and third levels 76, 78 and 80 respectively which are shown in Figure 2.

Under rest conditions the tank 24 will be maintained with a water level at the first level 76 which is a distance Y of at least 22mm beneath the invert 82 of the overflow slot 50. In order to ensure that contamination of fresh water in the pipe 60 cannot occur, the discharge aperture of the fresh water inlet fixture 54 is a distance X of at least 25mm above the slot invert 82.

When a cistern in the house demands water it will flow to the cistern via the third pipe 44. The level of water will fall below the first level 76 and the float 66 will consequently fall also. It is not until the water in the tank reaches the second level 78 that the float 66 will come to rest on the bottom stop 70, thus causing the arm 72 to pivot anticlockwise, as seen in Figure 2, and effect actuation of the motor 34 and pump 32. The pump 32 then draws water from the reservoir 8 through one-way valve 20, and pipe 18 and forces it through second pipe 38 and the inlet fixture 40 into the tank 24, thus raising the water level therein. Once the first level 76 is reached the float 66 comes into contact with the upper stop 68 on the rod 64 and causes the arm 72 to rotate clockwise, thus deactivating the motor 34 and pump 32.It should be noted that at no point in the above described sequence will fresh water enter the tank via the inlet fixture 54.

Should the pump be unable to provide recycled water to the tank 24, the water will eventually fall below the lowest third level 80 at which point the float 58 will fall thus allowing fresh water to enter the tank from pipe 60 via the fresh water inlet fixture 54. Once the water has risen to the third level 80 which is less than 100mm and preferably approximately 50mm from the bottom of the tank, the float 58 will cause inflow of fresh water to be cut off. The third level 80 is arranged to be above the outlet fixture 46 in order that a supply of water to the cisterns can always be guaranteed and above the level of the inlet aperture 42 of the recycled water inlet fixture 40 in order that the pump 32 is always in a flooded condition (as water cannot run down the pipe 18 back to the reservoir 8 because of the one-way valve 20).

Control of the motor 34 may be dependent on factors such as the level of water in the reservoir 8 and the temperature of the pipe 8 supplying the pump. Figure 4 shows in diagrammatic form a control means suitable for controlling a flow of electricity to the motor 34 for driving the pump 32. Power is supplied via wire 88 to a water level sensor 82 located near the bottom of the reservoir 8. The sensor is connected in series via wires 86 to a temperature sensor 84 and the float switch 62.

Only if (a) there is adequate water in the reservoir, (b) the temperature is above freezing and (c) the water in the tank 24 is at or below the second level 78 will the motor 34 be actuated.

The volume of water accommodated in the tank 24 between the first and second levels 76 and 78 is approximately 60% of the volume of water accommodated in the tank when filled to the first level 76, and represents the approximate volume of water demanded by a single flush of a typical water closet cistern.

The means by which the float switch is actuated to prevent rapid on-off cycling of the pump may constitute an invention independently of other features discussed. The form of the tank and associated support structure and container may likewise constitute an invention independently of the other features discussed.

Claims (15)

1. A water recycling break tank apparatus including a tank, a recycled water inlet with a discharge aperture, an unrestricted overflow, a fresh water inlet with a water level-dependent first control means and a discharge aperture positioned above an invert level of the overflow and a recycled water supply outlet, wherein the first control means is arranged always to maintain the supply outlet submerged.

2. A break tank apparatus according to claim 1 wherein the unrestricted overflow is provided by an elongate aperture in the side of the tank.

3. A break tank apparatus according to claim 1 wherein the unrestricted overflow is provided by a weir region of reduced height in a sidewall of the tank.

4. A break tank apparatus according to any preceding claim wherein the discharge aperture for recycled water is located at less than 20% of the height of the tank above its bottom.

5. A break tank apparatus according to claim 4 wherein the first control means is arranged to allow fresh water into the tank to keep the recycled water supply outlet submerged but to cut off the fresh water supply when the depth of water in the tank is more than 20% of the tank's height.

6. A break tank apparatus according to any preceding claim wherein the break tank is positioned above a container arranged to collect any overflow water from the tank and route it to the exterior of a building in which the apparatus is located.

7. A break tank apparatus according to claim 6 wherein the tank is supported above said container by a walled structure within which is located a pump arranged to supply recycled water to the recycled water inlet.

8. A break tank apparatus according to any preceding claim which includes a pump arranged to supply recycled water to the recycled water inlet and second control means arranged to start the pump only when the water in the tank falls to a first low level and to stop the pump when the water reaches a second higher level.

9. A break tank apparatus according to claim 8 wherein the difference in height between said higher and lower levels represents at least 40% of the height of the tank.

10. A break tank apparatus according to claim 8 or claim 9 wherein said second control means includes a float the weight of which causes the second control means to start the pump when the water is at said first level and the buoyancy of which causes the second control means to stop the pump when the water reaches said second level.

11. A break tank apparatus according to any one of claims 8 to 10 wherein the second control means includes an override system for preventing pump actuation when a supply of recycled water is not available.

12. A break tank apparatus substantially as herein described with reference to the accompanying drawings.

13. A water recycling system comprising a break tank apparatus according to any preceding claim and a recycled water reservoir located below the break tank, a pump being arranged to supply water from said reservoir to the recycled water inlet of the tank.

14. A water recycling system according to claim 13 wherein a one-way valve is provided which prevents the flow of water from the pump back into the reservoir.

15. A water recycling system substantially as herein described with reference to the accompanying drawings.