Patent Application
20140053909
The present invention relates to a water recirculation system, and in particular to a water recirculation system that may be employed in a washing unit such as a shower or a bath in order to recycle and save water.
One of the biggest problems facing the population today, and increasingly more so over the next few decades, is the dwindling resource of water on this planet. Human beings simply cannot function without a water supply. We need a constant supply to consume just to stay alive, remain hydrated and regulate our bodies' temperature. In addition, everyday water is used in a variety of scenarios from simple domestic cleaning and washing purposes, to larger scale industry, cooling, cleaning, crop watering and leisure applications. Sooner rather than later the finite supply in aquifers will run out and the supply of fresh water circulating on Earth will cease to meet our needs, with some experts predicting that natural water stocks will run out quicker than those of supposedly more valuable fossil fuels such as oil and natural gas. Efforts are being made to reduce consumption of water. For example, the European Commission has set a target that the average domestic usage of water in the European Union should be reduced from 140 litres to 120 litres per person per day by 2020.
One of the biggest drains on our water supply in the developed world occurs when baths or showers are taken. Although it is widely acknowledged that a shower uses less water than a bath to clean oneself, this is only true when the shower is run for a short period of time or when the shower head is unable to deliver large volumes or high flow rates of water. Such high flow rate showers are typically referred to as ‘power showers’. Although providing a pleasurable and relaxing experience for many people, as well as affording the opportunity to wash away dirt and grime from our bodies, any type of shower (eco-shower, regular shower or power shower) that is allowed to run for a considerable period of time will produce large volumes of waste water. An average shower lasting no longer than five or six minutes will produce 50 litres of waste water. In reality, many showers last much longer or use higher flow rates so will waste larger quantities of water. Any efforts therefore to reduce water consumption from baths or showers, or to put the waste water to better use than to allow it to simply drain away, must be considered beneficial.
It would therefore be advantageous to have a system which is able to continuously re-circulate or recycle water from a shower system so that only a small quantity of water is used during the whole washing process. In addition, it would be desirable to change the source of the water flow within the circulating system so that fresh water can be introduced at a user's command, while at the same time evacuating the used waste water from the shower system. It would be especially desirable to be able to maintain the operating temperature and flow rate of the water within the shower system while it is being re-circulated, so that a user is not affected by irregularities in the temperature or pressure of the water with which they are washing.
The invention provides a water recirculation system comprising a plurality of reservoirs supplied from a water source; a washing unit to receive water from the reservoirs; a pump connected to return water from the washing unit to the reservoirs; and switching means for selecting from which of the reservoirs the washing unit receives water.
The water recirculation system is preferably configured so that users may make use of the washing unit to clean themselves with water that has been stored in one of the reservoirs. The reservoirs, which preferably contain heating elements, are supplied with water from a mains supply which optionally may pass through a non-return valve. The washing unit is preferably a shower unit and further comprises a waste trap incorporating a filter. The water recirculation system is preferably configured so that a user may utilise heated water that is circulated from one of the reservoirs in a continuous fashion in order to wash themselves, before switching to heated water that is circulated from a second reservoir. In this way, a limited quantity of water is circulated through the recirculation system allowing a user to save water during the process of taking a shower. The user may switch the source of the water, at their discretion, to permit a fresh supply of clean water to be introduced into the recirculation system from the second reservoir in order to rinse away, for example, excess cleaning products.
The waste water from the shower is collected and optionally passes through a flow switch before being returned to the active reservoir by the action of the pump. Preferably a multi-way junction is positioned downstream from the pump so that water may be routed to a selected one of the reservoirs at the command of the user. Each reservoir has separate inlet and outlet means to distribute water from a) the water source to the reservoirs, b) the pump to the reservoirs, c) the reservoirs to the washing unit and d) the reservoirs to a drain. The inlet and outlet means to distribute water around the recirculation system are preferably solenoid-operated valves to control the circulation of water, filling of the reservoirs and, as will be seen, the evacuation of waste water from the system. The control means are ultimately commanded by a user, according to their own specific needs.
It is preferable that at the same time as switching the source of the water circulating within the system from one reservoir to another, a simultaneous evacuation of the waste water occurs. When the water source is switched, the system purges the waste water from the reservoir no longer supplying the shower unit by displacing the waste water with clean water which is received preferably under pressure from a mains water supply. The waste water previously contained within the reservoir is discharged out of the recirculation system through a drainage port. The clean water entering the reservoir is then heated in readiness to be supplied to the shower unit as and when required. It is therefore preferable that a user is able to switch the water supply from a first reservoir to a second reservoir, and back to the first reservoir as often as they require. It is preferable that the system operates with only one heater in use at any one time in order to save energy usage.
It is preferable that the system further comprises a supplementary tank located between the washing unit and the pump, which provides a supply of water for the pump to draw from when first operated. The supplementary tank may also preferably comprise a sensor to determine the volume of water in the tank. When the volume of water falls below a pre-determined limit, the sensor will cause the supplementary tank to be re-filled with water. The system may further comprise a bypass pipe from one of the reservoirs to the supplementary tank, whereby water can be circulated through the system while bypassing the washing unit used. The system can be programmed to periodically circulate the water in this way prior to use of the washing unit so that the water within the system can be maintained to a sufficient temperature for washing. In this way, when a user commences a shower, there is no delay or lag in having to wait for water of a desirable temperature to warm up in the system. It is available on demand.
It is also highly preferable that the water recirculation system has a self-cleaning function, allowing the system to raise the temperature of the water in the reservoirs to a sufficiently high temperature in order to kill water borne pathogens. It is envisaged that a safety means will be introduced that does not permit users to implement the self-cleaning step of the system while they are using the shower, in order to avoid the risk of scalding themselves with hot water.
It would be highly preferable if the system comprises a cleaning apparatus for killing water borne pathogens, preferably in at least one or in both of the reservoir tanks A silver electrode based cleaning apparatus has been proven to be highly effective at minimising or reducing water borne pathogens in a supply of water. When programmed to do so, a small quantity of silver ions is introduced into one or more of the reservoir tanks by application of a small current across the silver or silver-copper electrode.
The invention as described above solves the problem of providing a water recirculation system that may be used to continuously re-circulate or recycle a small quantity of water while a user takes a shower. In particular the water recirculation system permits the user to change the source of water that is flowing within the recirculation system so that a fresh supply of water may be introduced into the shower at a user's command. The system also permits the simultaneous evacuation from the shower system of waste water that has been generated. In addition, the water recirculation system does not limit a user's experience of taking a shower as the user is not affected by irregularities in the temperature or pressure of the flow of water when the water recirculation system is operating because the circulating water is isolated from the remainder of the household water system. Because of the small total amount of water in the system, the heaters are able to maintain a constant temperature of the water even when the waste water evacuation and replacement steps are performed. Most particularly the water recirculation system is capable of operating while recirculating only about 5 litres of water, allowing significant savings to water consumption and cost to be made. With a sufficiently powerful pump, flow rates well in excess of 10 litres per minute can be achieved, to compare favourably with the experience of existing ‘power showers’ but without that flow of water running to waste.
Referring now to the drawings,
The system 1 comprises a shower unit 2 in connection with a pump 4 and two water reservoir tanks 6a,6b, which may conveniently be located beneath a shower tray (not shown) in the base of the shower unit 2. The shower unit 2 may be any standard shower unit with a shower head 8 as is familiar to a person skilled in the art. The tray of the shower unit 2 contains a waste trap 10 to collect the water from the shower head 8, which either falls directly into the waste trap 10 from the shower head 8 above or is water spray that runs from the sides of the shower unit 2 or from a user of the shower and accumulates in the waste trap 10. The waste trap 10 also incorporates a fine, e.g. 250 μm, filter (not shown) to prevent waste elements from the used shower water, such as body hair or grains of dirt, from entering the recirculation system, where they could prevent the correct operation of the valves for example.
The pump 4 is connected to the waste trap, from which it pumps water, preferably via a flow switch 12. The pump 4 will typically have a power in the range 300 W to 600 W, depending on the flow rate that is desired and the resistance to flow that is presented by the recirculation system 1. The outlet of the pump 4 is connected to the inlet of a first three-way junction 14, which in turn has two outlets coupled respectively to the two reservoirs 6. The flow switch 12 prevents the pump from operating if there is an insufficient flow of water from the waste trap, which could cause the pump to run dry and be damaged. Insufficient flow is most likely to be the result of a blocked filter and the user may be given a message via the control panel to indicate that the filter should be cleaned.
The reservoir tanks 6 may be made from any suitable material such as steel, copper or plastic that will not degrade in the presence of hot water. Each of the tanks is configured to hold a quantity of water that will be re-circulated through the system when a user takes a shower. It is anticipated that each of the tanks will typically have a capacity of about 3 litres of water, in order for the water recirculation system to remain economical in terms of water and power usage, although it is anticipated that the reservoir tanks may hold any sufficient quantity of water to permit a user to take a shower, bearing in mind that some water will inevitably be lost from the system during use owing to wetting of the user and of the walls of the shower unit 2. The relatively small capacity of the reservoir tanks 6, in comparison with the amount of water that is typically used during a normal shower, will not affect the performance of the recirculation system 1. It is envisaged that the recirculation system 1 will be able to consistently deliver flow rates of between 11 and 22 litres of water per minute in use, which compares favourably with flow rates of normal showers which are only in the region of 6-9 litres per minute. Although illustrated as discrete components in the schematic
Each tank 6 also comprises a heating element 16 of a power sufficient to raise the temperature of the water in the tank rapidly to a desired temperature for taking a shower, for example 40° C. For example, a 3 kW heater may raise 3 litres of water to 40° C. in approximately 70 seconds. Once up to temperature, the rapid recirculation of a small quantity of water through the system results in a short time to return to the heater and only low power is then required to maintain the water at the desired temperature. The temperature may be selected by the user and maintained by switching the heater 16 on and off under the control of a thermostat in a conventional manner.
Each tank 6 is fitted with a pair of inlet valves 20,22 and a pair of outlet valves 24,26 in order to regulate the flow of water between the tank 6 and the other parts of the system 1. The inlet and outlet valves 20,22,24,26 are individually controlled by solenoids under the command of an electronic controller (not shown), and connect the various components of the recirculation system 1 as follows.
The tanks 6 are filled with water which is supplied from a mains water supply 18 through a non-return valve 28 to prevent back-flow of water from the system 1 into the mains. Water from the mains supply 18 enters a second three-way junction 30, which distributes it to the respective tanks 6a,6b. A first inlet valve 20 on each tank can be operated to permit or prevent the flow of water from the mains water supply 18 into the tank 6. A second inlet valve 22 on each tank 6 can be operated to permit or prevent the flow of water from the pump 4 to the tank 6. A first outlet valve 24 on each tank 6 can be operated to permit or prevent the flow of water from the tank to the washing unit 2 through a third three-way junction 32 that connects both tanks 6a,6b to the washing unit 2. A second outlet valve 26 on each tank 6 can be operated to permit or prevent the flow of water from the tank to a drain 34.
In use, water is supplied from the mains water supply 18 to the system 1 prior to a shower being taken for the first time in order to fill up at least a first one of the tanks 6a through its open first inlet valve 20. The first inlet valve 20 is then closed and the heater 16 heats the water in the first tank 6a to the required temperature as defined by a user on a control panel (not shown) and the user may commence their shower. The first outlet valve 24 and the second inlet valve 22 are then opened to create a circuit through the tank 6a, the shower unit 2 and the pump 4. The pump is operated to push water from the tank 6a to the shower head 8 and is available for the user to wash themselves. Water and associated residue from the showering process collects in the waste trap 10 which filters out any significant foreign objects from the system. It is anticipated that the waste trap 10 will be designed to allow the filter to be removed easily so that it may be cleaned and maintained on a regular basis. As previously described, the water is removed from the waste trap 10 by the action of the pump 4, which returns the water to the first tank 6a after passing through the flow switch 12.
The water that is returned to the first tank 6a is therefore continuously circulated within the system 1, being re-heated to raise it to the desired temperature each time it passes through the tank 6a. When a user decides that the recirculating water is no longer sufficiently clean for washing, e.g. because it has become contaminated with dirt or with soap, shampoo or any other cleaning product, the user will require a fresh quantity of water with which to rinse themselves.
While water from the first tank 6a has been circulating through the system 1, the second tank 6b has been filled from the mains supply 18 and has also been heated to the user's desired temperature. Preferably, in order reduce the maximum power consumption, only one of the heaters 16 is operated at any time, with the heater 16 in the active tank 6 taking priority. Nevertheless, after the water in the first tank 6a has reached its desired temperature the associated heater should need to be operated only intermittently in order to maintain that temperature, thereby allowing sufficient time for the heater in the second tank 6b to raise the temperature of the second volume of water to the same level.
The user switches the flow of water circulating within the system 1 from the first tank 6a to the water from the second tank 6b by selecting the appropriate function on the control panel (not shown). The second inlet valve 22 and the first outlet valve 24 of the first tank 6a are closed and the corresponding valves of the second tank 6b are opened to create a new circuit through the second tank 6b, the shower unit 2 and the pump 4. The pump is operated so that the clean water from the second tank 6b is introduced into the system and circulates in a manner analogous to that already described.
Simultaneously, or after a short delay, the second outlet valve 26 of the first tank 6a—which has remained closed throughout the procedure described up to now—is opened to allow the dirty water that was flowing within the recirculation system 1 via the first tank 6a to be sent to the drain 34 and evacuated from the system 1. The first tank 6a is then re-filled with fresh water from the mains supply 18 and it is heated to the same temperature as previously selected in readiness for the next changeover of water supply if the user requires it. Preferably, the flow of water under mains pressure into the first inlet 20 of the tank 6 is used to displace the dirty water from the tank 6.
A user may switch the flow of the water within the water recirculation system 1 as often as they require within the course of a single shower, although it is expected that in most cases the user will use the water supply from each tank 6 only once. In this way, significant savings can be made in terms of water usage, which are mirrored by associated savings in energy consumption of the water recirculation system.
The water recirculation system 1 has a self-cleaning function, in which, when the shower is not in use, the heaters 16 can be used to raise the temperature of the water in the reservoirs 6 to a temperature high enough to kill water-borne pathogens, for example 65° C. This function could be instigated by the user from the control panel or automatically at predetermined time intervals. A safety means will be provided that prevents the pumping of high temperature water from the reservoirs 6 to the shower unit 2 while the self-cleaning operation is progress, in order to avoid the risk of scalding.
The system as described and illustrated has two reservoirs 6a,6b and the user may switch the water supply alternately between them. It will readily be understood that a larger number of reservoirs 6 could be provided, with the respective inlet and outlet valves 22,24 being operated so as to cycle the water supply among each of them in turn.
The reservoirs need not be simple tanks but can be any suitable shape that enables a sufficient volume of water to be held in thermal communication with the heater element. In particular, each reservoir 6 may contain internal walls (not shown) that define a one-way path from the inlet valves 20,22 to the outlet valves 24,26. This arrangement would help to ensure that, when clean water from the mains supply 18 is used to displace dirty water from the tank 6 to the drain 34, there is minimal mixing between the clean and dirty water. On the other hand, it would reduce convection within the tank that might otherwise help to ensure a uniform water temperature. Taking this development a stage further, each reservoir could take the form of a coiled or convoluted pipe with the heater element running along its length.
Forms of heating other than electrical elements could be used in connection with the invention. For example, with a more complex plumbing arrangement, the water could be directed to pass through the heating unit of a combination boiler. It might be possible for all of the reservoirs to share a common heating unit.
As described, each of the inlets and outlets 20,22,24,26 of the tank 6 is regulated to be opened or closed by its own solenoid-controlled valve. By changing the configuration of open and closed valves, different circuits and flow paths through the system 1 can be selected. A different way of achieving the same end would be to remove the inlet and outlet valves 20,22,24,26 from the tanks 6 and to insert multi-way valves in place of the three-way junctions 14,30,32. The flow paths through the system 1 could then be reconfigured by changing the positions of the multi-way valves. For example the first three-way junction 14 could be replaced by a valve with three positions: one that blocks the flow of water from the mains supply 18, one that directs water from the mains supply 18 to the first tank 6a, and one that directs water from the mains supply 18 to the second tank 6b.
The system of this embodiment further comprises a bypass pipe 37 that is not present in the system of
The heater (not shown in
As previously described in connection with the embodiment of
Because some used water remains in the pipework and in the supplementary tank 36 at all times, switching the source of water for the washing unit 2 from one reservoir 6a,6b to the other reservoir 6b,6a will not immediately replace all of the used water in the system 1 with fresh water. The proportion of water replaced on each changeover will depend on the capacity of the reservoirs 6a,6b relative to the remainder of the system 1. For the maximum use of fresh water, it is possible to program a “rinse” mode of operating the system 1 that automatically and repeatedly switches between the reservoirs 6a,6b as soon as the next reservoir 6a,6b has been filled and raised to the desired temperature. Of course, operating in this mode will detract from the water- and energy-saving benefits that the system 1 is capable of providing.
After usage of the system 1 has occurred, the various pipes and in particular the supplementary tank 36 and at least one of the reservoirs 6a,6b will be filled with used water. It may be desirable to flush the system with fresh water, e.g. before the washing unit 2 is used by a different person.
Fresh water enters the system 1 from the mains water supply 18 and, by closing valves 20a, 20b and opening valve 48, is routed through the second three-way junction 30 and a sixth three-way junction 51 before passing into the supplementary tank 36. The fresh water dilutes and displaces the used water from the supplementary tank 36, which passes through the non-operating pump 4 before being transferred to the first three-way junction 14. Valve 22a is open and valve 22b is closed so the flow of water is directed into the first reservoir tank 6a, and exits from the first reservoir tank 6a through valve 26a before passing through the fifth three-way junction 50 and exiting the system 1 at the drain 34.
In a further mode of operation (not illustrated) for flushing the system of
Despite the fact that
For example,
Even without the four-way junction 52 shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 1107310.3 | May 2011 | GB | national |
| 1202163.0 | Feb 2012 | GB | national |
This patent application is a continuation of PCT/GB2012/050933, filed Apr. 27, 2012, which claims priority to Great Britain Application No. 1107310.3, filed May 3, 2011 and Great Britain Application No. 1202163.0, filed Feb. 8, 2012, the entire teachings and disclosure of which are incorporated herein by reference thereto.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/GB2012/050933 | Apr 2012 | US |
| Child | 14067544 | US |
