Background of the Invention Conventional showers typically consume significant amounts of both fresh water and heat energy. The excessive consumption of fresh or clean water is often of particular concern, not only in situations where fresh water supply is limited by location or climatic conditions, but also in other environments such as caravans, boats and passenger planes where only limited capacity exists for fresh water storage.

A further problem stemming from the use of conventional showers is the inability of many hot water supply systems to keep up to the demand for hot water at peak periods, such as the demand on many household systems during mornings before work or school. At such times when several showers may be taken by members of the same household within a short period of time, the hot water supply may be temporarily exhausted, or in the instance of several simultaneous users, the water pressure may be subject to considerable variation. This problem may also arise at other venues of excessive shower/hot water demand such as at hotels, and amenity blocks at caravan parks and camping grounds, for example.

Summary of the Invention According to one aspect of the present invention, there is provided a recycling shower system including: a tank for receiving used water from a shower; means for feeding fresh water into the system; a pump for feeding water from the tank through a heater to the shower; and discharge means for permitting a discharge of a portion of the used water from the system to a waste water outlet during operation of the system to facilitate replenishment with fresh water, with replenishing fresh water being fed into the system during operation.

Preferably, fresh water is fed into the tank, and the discharge means discharges the portion of the used water from the tank.

Preferably, the tank is a sump into which water can drain from the shower.

Preferably, the discharge means is operable to permit the continuous discharge of water from the tank during operation of the system.

Preferably, the tank includes a discharge outlet that is closed when the system is in operation and that is open when the system is not in operation to permit drainage of contents of the tank to the waste water outlet. More preferably, the system includes a plug for closing the discharge outlet. Preferably, the plug has a lower portion for closing the discharge outlet and a tubular upper portion, the upper portion defining a passage which continues through the

lower portion and through which water from the tank is able to flow to the waste water outlet.

Advantageously, overflow water may flow from the tank into the passage if the water level in the tank rises to or exceeds a predetermined level that is greater than the normal operating level of the water within the tank during operation of the system.

The discharge means may comprise a discharge orifice leading into the passage below the normal operating level of water within the tank during operation of the system, or an outlet leading from the tank below the normal operating level of water within the tank during operation of the system. Preferably, the discharge orifice or the outlet leading from the tank is disposed at a height close to the normal operating level of the water within the tank during operation of the system to promote the discharge from the tank of water having soap and other impurities that tend to float on or near a top of the water within the tank.

Preferably, a control unit of the system includes means for actuating the system by allowing an initial intake of fresh water into the tank to fill the tank for operation, and a time delay for delaying the operation of the pump until the tank contains sufficient water for the operation of the pump.

Preferably, the means for feeding fresh water into the system includes a float valve responsive to the water level in the tank and connected to a fresh water inlet line, the float valve determining the normal operating level of the water in the tank during operation of the system.

Preferably, the system includes a filter for removing soap and other impurities in the used water from the shower.

According to a further aspect of the present invention, there is provided a method for recycling water for use in a shower comprising collecting used water from the shower, and pumping some of that used water together with replenishing fresh water back to the shower.

Preferably, the used water is collected in a tank from which water is bled during operation of the shower to permit replenishment of the tank by fresh water introduced into the tank.

Preferably, at the completion of a showering operation, the entire contents of the tank are discharged to waste and at the commencement of a subsequent shower, fresh water is fed into the tank.

Preferably, the method comprises heating the water pumped from the tank back to the shower.

Brief Description of the Drawings The present invention will now be described, by way of non-limiting example only, with reference to the accompanying drawing, in which: Figure 1 is a schematic view of a recycling shower system.

Detailed Description

A recycling shower system 2 that is able to be used to recycle water in a shower is shown schematically in Figure 1, in which electrical connections have been indicated by broken lines and fluid flows have been indicated by solid arrows.

The system 2 includes a fresh water inlet 4, a tank in the form of a sump 6 for receiving and storing both fresh water and used shower water, a water heater 8 for heating water from the sump 6, a submerged pump 10 for feeding water from the sump 6 through the heater 8 to the shower, and an electrically powered control unit 12 for controlling the operation of the pump 10 and the heater 8. The system 2 is preferably located adjacent an associated shower and an associated stall (both not shown), with a drain in a base of the shower stall being located substantially above the sump 6 to allow used water (hereinafter referred to as"grey water") from the shower to drain into the sump 6 through a return inlet 14.

The control unit 12 of the system 2 operates the pump 10 to feed the water that is stored in the sump 6 through the heater 8 to heat the water to a preselected temperature. The heated water is then fed under pressure through a shower water outlet 16 to the shower, with grey water from the shower draining back into sump 6. By circulating a mixture of both replenishing fresh water that is introduced into the sump 6 and the grey water that has been returned to the sump 6 from the shower, in operation, the system 2 is able to recycle the previously heated grey water to conserve both fresh water and heat energy used by the shower.

The sump 6 of the system 2 shown in Figure 1, includes a discharge outlet in the form of a drain 18 through which water from the sump 6 can drain into a waste water outlet 20 leading to a waste water system (not shown). A plug 22 that is movable between open and closed (shown in Figure 1) positions with respect to the drain 18 is provided within the sump 6 for closing drain 18. The plug 22 comprises a lower portion 24 that closes the drain 18 when the plug 22 is in the closed position and a tubular upper portion 26. The tubular upper portion 26 defines a passage 28 which continues through the lower portion 24 and through which water from the sump 6 is able to flow to the waste water outlet 20.

A manually operable lever 30 that is able to be moved between ON (shown in Figure 1) and OFF positions is provided for selectively turning the system on and off respectively. When the lever 30 is in the OFF position, the plug 22 is in the open position to allow the contents of the sump 6 to drain from the waste water outlet 20, a lever actuated supply valve 32 that in combination with a float valve 34 controls the flow of replenishing fresh water into the sump 6 is closed, and the control unit 12 is turned off. Turning the lever 30 to the ON position, via link rods 36,38, mechanically displaces the plug 22 into the closed position, opens the supply valve 32, and turns the control unit 12 on. Turning the lever 30 back to the OFF position after a shower is completed correspondingly mechanically displaces the plug 22 back into the open position to allow the contents of the sump 6 to drain to the waste water outlet 20, closes the supply valve 32 and turns the control unit 12 off.

The height at which a float 40 operably associated with the float valve 34 opens the valve 34 can be used to define the normal operating level 42 of water within the sump 6 during

operation of the system 2. When the system 2 is turned on, if the water level in the sump 6 is below the normal operating level 42, the float 40 opens the float valve 34 to allow replenishing fresh water to be fed from the fresh water inlet 4 into the sump 6. When the water level is at or exceeds the normal operating level 42, the float valve 34 closes to prevent further fresh water being fed into the sump 6. Only when the lever 30 actuated supply valve 32 and the float valve 34 are both open, corresponding to the lever 30 being turned to the ON position and there being insufficient water in the sump 6 respectively, may fresh water flow from the inlet 4 into the sump 6.

Although the illustrated system 2 comprises a float valve 34 that defines and maintains the water level within the sump 6 at the normal operating level 42 by feeding in replenishing fresh water during the operation of the system 2, it will be appreciated that other arrangements may be employed. For example, replenishing fresh water may be pumped into the system continuously at a predetermined rate, or at frequent intervals.

An overflow opening 44 is formed in the top of the tubular portion of the plug 22. The opening 44 is located at a height of a predetermined maximum water level of water within the sump 6 when the plug 22 is in the closed position that is above the normal operating level 42.

The overflow opening 44 prevents the sump 6 from overfilling by allowing water within the sump 6, if the water level within the sump 6 rises to or exceeds the predetermined maximum water level, to flow from the sump 6 into and down the passage 28, and to the waste water outlet 20.

It will be appreciated that the overfilling of the sump 6 could be guarded against in other ways. For example, alternatively an overflow opening leading to an overflow pipe in communication with the waste water system may be provided in a wall of the sump 6.

The system 2 also includes discharge means permitting the continuous discharge of water from the sump 6 to the waste water outlet 20. In the form shown, this is provided by a discharge orifice 46 formed in the tubular upper portion 26 at such a height that when the plug 22 is in the closed position, the orifice 46 is located below the normal operating level 42 during operation of the system 2. The discharge orifice 46 allows water to continuously bleed from the sump 6 and to drain into and down through the passage 28 to the waste water outlet 20 during operation of the system 2 at a predetermined flow rate to facilitate replenishment of the sump 6 with fresh water.

The flow rate of water from the sump 6 through the orifice 46 will be governed by the several factors, including the size of the orifice 46, which can be predetermined at the time of set-up of the system 2. Alternatively, the size of the orifice 46 may be able to be selectively varied each time before operation of the system 2, for example.

The discharge orifice 46 is located on the upper portion 26 of the plug 22 so that it is close to, but still below, the normal operating level 42 of the water within the sump 6 during operation of the system 2 when the plug 22 is in the closed position. The orifice 46 is advantageously located close to the normal operating level 42 during operation of the system 2 to promote the discharge from the sump 6 of water having soap and other impurities introduced into the

sump 6 with the grey water from the shower. It has been found that these impurities tend to float on or near the top of the water.

While the discharge means for permitting the introduction of replenishing fresh water into the illustrated system 2 is shown in the form of the orifice 46 formed in the plug 22 within the sump 6 that allows water within the sump 6 to flow to the waste water outlet, it will be appreciated that the orifice 46 may be provided in other locations. For example, alternatively, the discharge means may include an orifice, or a plurality of orifices, formed in the wall (s) of the sump 6 that may lead to one or more discharge pipes that lead to the waste water system.

Further, the discharge means could alternatively be in the form of a second pump that, either continuously or at frequent intervals, purges water from the sump 6 to the waste water system.

Further, it will be appreciated that the discharge means for permitting the replenishment of the system 2 with fresh water could alternatively be located substantially outside of the sump 6. For example, a discharge opening through which a portion of the grey water from the shower that would normally be returned into the sump 6 may be discharged to the waste water system could be formed in a returning grey water line returning grey water from the drain of the shower through the return inlet 14 into the sump 6, such as adjacent the drain of the shower or adjacent the return inlet 14.

A limit switch 48 that is in communication with the lever 30 by the link rod 36, controls the operation of the control unit 12 in response to the actuation of the lever 30. The control unit 12 is powered by an electric power source (not shown) via the power line 50. When the switch 48 senses that the lever 30 has moved to or is at the ON position, the control unit 12 is turned on, and when the switch 48 senses that the lever 30 has moved to or is at the OFF position, the control unit 12 is turned off. A time delay 52 in series with the limit switch 48 delays the turning on of the control unit 12 for a predetermined time each time the lever 30 is moved to the ON position. The time delay 52 permits a sufficient amount of water for the operation of the pump 10 to initially flow into the sump 6 from the fresh water inlet 4 before the control unit 12 commences operation of the pump 10 and the heater 8.

To operate the submerged pump 10, the control unit 12 supplies electrical power to a motor 54 that rotates a drive shaft 56, as indicated by arrow 58, which mechanically drives the pump 10. The pump 10 feeds water from the sump 6 to the heater 8 through a filter 60 that removes soap and other impurities in the water. While the filter 60 of the illustrated system 2 is located between the pump 10 and the heater 8, it will be appreciated that it may be located elsewhere. Alternatively, for example, the filter 60 may be disposed in the drain of the shower stall, or further alternatively, at the grey water return inlet 14, to filter grey water at the time it is returning from the shower into the sump 6. Advantageously, the filter 60 includes a lid 62 by which it may be readily opened for cleaning.

The pumped water flows under pressure from the heater 8 through a pressure switch 64 and to the shower water outlet 16. The pressure switch 64 limits electrical power being delivered

to the heater 8 to prevent the operation of the heater 8 when there is insufficient water pressure. Only when the pump 10 has built up the water pressure to a predetermined minimum pressure does the control unit 12 supply power to the heater 8 for heating the water.

An overpressure relief valve 66 may also be provided downstream of the heater 8 to guard against blockage of the shower, by preventing the pressure of the water exceeding a predetermined maximum pressure. The overpressure relief valve 66 acts to divert water back to the sump 6 to relieve pressure, as indicated by the arrow 68, when the pressure of the water being fed through the heater 8 exceeds the predetermined maximum.

To heat and control the temperature of the water, the control unit 12 includes a user control 70 and a thermostat 72. The user control 70 allows a user to preselect a desired temperature of the shower water. The thermostat 72, which is located between the heater 8 and the shower water outlet 16, senses the temperature of the water flowing to the shower water outlet 16 and feeds the sensed temperature back to the control unit 12. The control unit 12 is then able to uses this fed back temperature to regulate the power supplied to heater 8 to control the temperature of the heated shower water to the preselected temperature. A safety over-temperature switch 74 that senses the temperature of the water in the heater 8 may also be provided to prevent electrical power being supplied to the heater 8 if the sensed temperature of the water exceeds a predetermined safe maximum temperature to prevent the shower water being overheated.

The water heater 8 will generally consume substantially the most energy at the beginning of operation of the system 2 when fresh water may need to be heated from the ambient temperature of the fresh water inlet 4 to the preselected temperature for the shower water.

After the system 2 has been in operation for some time, the temperature of the recirculating water will typically be substantially above that of the water from the inlet 4, and accordingly will require significantly less heat energy from the water heater 8.

Any suitable form of instantaneous water heater 8 with appropriate temperature control can be used in the system 2. The water heater 8 may be electrically powered as described herein, or alternatively gas powered, for example. In development of a system having an electrically powered water heater 8, the inventor found that water-proof micro controllers such as a PXW4 micro controller as marketed by Fuji Electric Co Ltd of Tokyo, Japan or a Shinko JCS controller, for example, provide very effective temperature control over the range of temperatures of typical fresh water supplies and desired shower water temperatures.

The system 2 can advantageously be retrofitted to an existing shower stall in such a manner that it may be used for the supply and heating of water when taking a shower. In the instance of a several adjacent showers, a separate system may be provided for heating the water for each shower, or a system or systems sharing one or more parts may be provided for heating the water for each shower, for example.

The operation of the system 2 shown in Figure 1 will now be described, by way of non- limiting example.

To operate the system 2 to take a shower, a user initially preselects the desired shower water temperature using the user control 70. The system 2 is then turned on by moving the lever 30 to the ON position to close the plug 22 in the drain 18, and to open the supply valve 32 to allow the float valve 34 to fill the sump 6 with fresh water to the predetermined normal operating level, and to trigger the limit switch 48 to activate the control unit 12.

The time delay 52 allows the sump 6 to fill with sufficient water for the operation of the pump 10 before activating the control unit 12. After the predetermined time delay, the activated control unit 12 operates the pump 10 by suppling power to the motor 54 to drive the pump 10 to feed water under pressure from the sump 6 through the filter 60 to the heater 8.

When the pump 10 has built up sufficient pressure, as determined by the pressure switch 64, the control unit 12 supplies power to the heater 8, with the control unit 12 regulating the power supplied to the heater 8 to control the temperature of the water to the preselected temperature. The safety over-temperature switch 74 prevents the heater 8 from heating the water for the shower above a predetermined maximum safe temperature in the instance of a malfunction of the control unit 12 and/or the thermostat 72, while the overpressure relief valve 66 relieves the heated water of excess pressure.

The heated water flows under pressure from the heater 8 to the shower water outlet 16 to the shower, where the heated water may be used by the user to take a shower. The grey water from the shower is subsequently returned from the drain at the base of the shower stall

through the return inlet 14 into the sump 6 for recycling and recirculating through the system 2. The overflow opening 44 within the sump prevents the sump 6 from overfilling.

During the shower, the discharge orifice 46 allows water in the sump 6 to bleed from the sump 6 to the waste water system at a predetermined rate, as previously described. The flow of a portion of the water out of the sump 6 causes the level of water in the sump 6 and the height of the float 40 to drop, thereby opening the float valve 34 and allowing fresh water from the fresh water supply inlet 4 to flow into and replenish the sump 6. By allowing a portion of grey water to flow out of the sump 6, the orifice 46 permits the continuous introduction of a portion of fresh water into the system 2 during operation of the system 2 whilst keeping the total amount of water in the system 2 substantially constant.

After the shower is completed, the lever 30 is moved to the OFF position to close the supply valve 32, and to turn the control unit 12 off, and to move the plug 22 to the open position to open the drain 18 in the sump 6 to allow substantially the entire contents in the sump 6 and the remainder of the system 2 to drain to the waste water outlet 20.

The results from a functioning prototype of the system 2 developed by the inventor are presented below as a non-limiting example only, and it is expected that they would be subject to considerable variation depending on a several factors, including, for example, the water pressure of the shower, the efficiencies of both the pump 10 and water heater 8, and the difference between the temperature of the water from the fresh water inlet 4 and the preselected shower water temperature.

The prototype had a sump 6 having a predetermined level for water in the sump 6 during normal operation corresponding to a capacity of approximately 8 litres, as determined by the vertical position of the float 40 of the float valve 34, and a discharge orifice 46 sized to discharge approximately 1 litre/minute. The fresh water used was initially of ambient temperature. When used to supply and heat water for a 10 minute shower at 41 degrees Celsius, the system 2 used approximately 18 litres of fresh water and approximately 1.25 kilowatt-hours of energy.

It will be appreciated that the present invention has been described by way of non-limiting example only, and modifications and variations may be made without departing from the spirit and scope of the invention described.

Throughout the specification, unless the context requires otherwise, the word"comprise", and variations such as"comprises"or"comprising", will be understood to imply the inclusion of a stated step or integer or group of steps or integers but not the exclusion of any other step or integer or group of steps or integers.