GB2484100A - A fluid recirculation method and device - Google Patents

Abstract

The invention relates to a method and or system for reducing water wastage in a water supply system by re-circulating cold water that reaches' a water outlet until such time that the water reaching the water outlet is at a predetermined temperature. The diverted water is directed to a pump 34 to increase the pressure of the diverted water above the pressure of the water supply 21, before reintroducing the diverted water back into the water supply system. Later embodiments relate to a control means I for a device 32 that increases the pressure of diverted water from a fluid-saving device so that it can be introduced back into a closed system. The control means may comprise a housing (2 figure 1) having a first chamber (7 figure 1) with an inlet (3 figure 1) that is connectable to a source of redirected fluid, a second chamber (8 figure 1) with an aperture (5 figure 1) that is open to the atmosphere, and a third chamber (9 figure 1) with an outlet (4 figure 1) that is connectable to an electric pump.

Description

A FLUID RECRCULKflQN METHOD AND DEVCE Fi&d of the invention The present invention relates:f a WateNsaving devices and in partcular to deyiqes'tor introducing divertedW&erback into the water suppiysysthrn: of a building H.

Background of tho

The conservation of dean water is of increasing conem. This concern is most clea.rly feJt n areas of the World $uch as. Africa, the Middle East and Austr1ia, where the environrn, nt: can be h.ärst However, aen tn countries with a plentiful supply of water, domestic water must be stored in reservoirs and it must be treated to be fit for huma.n consumption, In areas where water is in plentiful supply, the levels of wasted water are high On an individual level waste may not be huge, but the accumulated wasted water from all the users represents a large amount of clean water that ias'im ply ed down the:, drain.

One particular source of waste occurs every morning when it takes time for the hot water to come through the water pipes to the hot tap. As a result the f[rt user at each tap usually turns: on the tap until the. water runs hot In this way, in any one city on any one morning millions of litres of clean water can be wasted.

Various solutions to the above problem have be put:forward. However, all of the offered:5otipns have disadvantages, which have preented their widesc:ale a�QPtIQfl.

Canadian Patent No 2252350 describes a water supply system wherein water that is either too hot or too cold is prevented from exiting the system via an open tap. The system prevents:the wastage of water discussed above by diverting water of the wrong temperature back around the system until the water reaching the chosen tap is the correct temperature One of the main problems with the above system is that it requires a complete replumbing of the water supply system including the pipes and taps:, This may not be a huge issue' with new build properties; but it can be

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prohibitive iii OldEr properties1 wheretM tQta1J water savingS by the indIvidual property do not warrant the plumbing costs Furthermore the nature of the valve system used in Canathan Patent No 225235Q is such that new bathroom furniture (e g taps showerheads, etc) must be fitted also This further iflCreases the cost involved as well as limiting the levc:l of aesthetc choice avaithbie.'to the ownersofthe property.

Another solution is offered by the demand system, this system uses the same principal as is used for central heating, it has the hot water being constantly pumped around the. water' pips, so when a tap is opened the passing hot water is there ready,. for use, this system requires' quite an alteration to the plumbing, also needs a supply of electricity for the pump and switches and a water pump that is expensive to buy and run, it also needs the returned and cooled water to be constantly re-heated which is a very uneconomical operation, and is therefore both expensive to install arid run, and uses large amounts of valuable energy to constantly re-heat the circulating water The actual system is extremely expensive and the cost is not recoverable from saved water bills, so is in very little use, and rarely seen on the rnsrket, US Patent No.4554668 is an example: of this form of: water supply system.

US Patent No 5165456 describes a more basic solution to. the above-mentioned problem with the previously wasted water being diverted, to a portable water tank Whilst such invention provices a solution to the above problem without the disadvantages of the Canadian patent the invention is impractical and intrusive. The constant. n:eed for the user to lift and move the water storage tank would inevitably lead to'the system being abandoned.

International PCT Application. Np. AU2004/O:0041 5 discloses a water recovery system that addresses the above identified problem by oroviding a valve assembly that can be fitted into the plumbing upstream of a tap outlet The valve assembly ensures that only water that is above a predetermined temperature reaches the tap for discharge. The water that is not above, the predetermined temperature is recircul.ated. back around the water system.

The valve assembly is activated by a drop in water pressure at the tap outlet, which occurs when the tap is thm'ed on. This avoids the. need for any. sort of mech:ard*qal conmctibn between the valve asserbEy and the tap o:Utiet fl was described:j UK Application Na 0520317.9.

A1.thou9h PCTIAU2004/O0.O415 provides an effective solution.. to the athove identified i2rbbIems the disIt$S VäiVS äeflbIy requires *expensia and so'm&inies unreliable cornpore.nts. The use of large cerarr1.c cQmponents for example, which require a high level of precision, means that the: cost of manufacturing the valve assembly can prohibitive Also the use of the sometimes unreliable diaphragm in the valve assembly can lead to additional repair cost.s for the user.

There are now a number of thermal divertet valves being developed to save the Waterthat haS 000lled in the hot tap supply pipes: apd is generally runH off down the drain, any example: of which: Is International PCT ã�plication PC*T/G82008/002989, which is. also in the flame of the current:ihventQr.

AU of these systems divert the cooled water to outside storage, or an internal tank Which then has to use a pump with the associated wiring to the location of the storage vessel, which would often be some thstanceaway, and not in a convenient position, for where the saved water is needed for reuse, and the user has to be constantly vigilant to prevent the storage vessel/s from overflowing and causing possible expensive flood damage to property etc There. have also been a few return systems. that lower the pressure in the cold water line, using a standaid pressure reducing valve, and linking the saved return water from the hot tap supply pipe, directly to the cold tap supply pipe In this way the saved slug' of water can be fed directly into the cold watei line due to the created pressure gradient In situations where a cold outlet open is not open all of the time, a pressure resistant storage/accumulator tank needs to be installed, so that when any cold tap/outlet was opened the stored water would then be sent to the open outlet by virtue of its pressure being higher than the cold tine due to the pie sure gradient, between the hot and cold supply lines.

This above approach, although quite. effectiye, is illegal to use due to the formation of several very dangerous bactena, such as salmonella and legionella, that breed in enclosed heated and cooled water pipes and containers, and naturally contravenes, water regulations in virtually every CoUntry throuçh:out the world,. and storing he ted and cooled water in: pipes and containers, & known to be the cause.o:f a large number of deaths annually throughout the world, in many hospita!s and institutidn5 etc. In view of the above reguEations it is obviously more desirable to re-introduce the s'ug' of saved water back into the upstream supply pipe to the water heater HOwever this has up to how been considered impossible, due to the fact.that an enclosed watersystem has an equal pressure' throughout the system when the system is closed (i e no outlets are open) At present it is not ppsahIe. to return the sli4 of Saved water back ih to the supply side (upstream) :f the water heater so it can: be reheated and used agaiit.

Summary of the ihvehtion

The presetit inventiQn provides.a method of reduáing water Wastage in a water supply system by re-circulating water that reaches a water outlet until such time that the water reachng said water outlet is at a predetermined temperature according to claim 1.

In accordance with the method of reducing water wastage another aspect of the present invention provides a device that is intended to be used in concert with those water-saving devices that prevent water leaving the water outlet (8.9. hot tap) of a water supply system until the water is at a predetermined temperature. The present invention thus provIdes: a device according to claim 10, which may be used in accordance with the above method: to re.-int:roduce redirected. fluid., arid in particular wäter back in to a closed Th'id, supply system.

Another aspect of the present invention provides a control means according to claim. 3 for use in the above mentioned device'. The control means of the device operate the means for increasing the pressure. of the water that: is diverted to it from, for example. a tem.perature Sensitive. .diverier valve so that the water can be re-introduced into the water supply system down a pressure gradient.

Preferably the piston of theco.nttc.J means may be received: within the housThg so as to define a wall of the first chamber and a wall of the second chamber..

Pr: ferably the. switching means of the control means may comprise a sv.itchE that isrr..echanicaliy operate by the movement cf the piston' within th,e housing. Further preferab'y the swtching means may comprise a first mägñêt, located on the piston, and a second. magnet, located on the switch, and wherein the: movement of the pistOn withiti tM housing ohariges the relative posthonrng of the fwst and second magnets thereby generating a repthsive forte that bp.eratcs the switch.

Prtfera.bly the control means may further comprise. resilIent biasing means that default the piston to the closed position Alternatively the piston may be suitably weighted so that the iStbh is biased tow a rds the clcsed position hyaction Ofl the force of gravity on the pistorn Preferably the pressure increasing means of the device may compnse an electric: pump. It is appreciated that:alternEtive mechanisms for increasing the water pressure may also be used without departing from the: concept of the present invention.

In addition to the above mentioned control means and device, the present invention also provides a water-saving system which: comprises the device of the present invention The present invention provides a water-saving systemI abcording to claim 14.

Preferably the conduit of the water-saving system may be connected so as to introduce the water into the: system upstream of the water heating means.

PJternatively the conduit of the water-saving system may be connected so as to introduce the water into a storage tank which feeds back into the system downstream of all the drinking water oUtlets in the system. Further preferably the system may also comprise a non-return valve to prevent introduced water exiting the system via a drinking water outlet.

Brief Description of the Preferred Embothments of the Present Invention The present invention will now be described with reference to the drawings, wherein: Figure 1 shows an exposed side view of the control means of the device: of tho present Invention:; Figure 2 shows a first preferred arrangement of the water supply system bfthe present invention; and Figure 3 shoWs a second preferred arrangement of a water sufl system of the present invention.

Detailed Descrtpfión of thePrefsrrod. Enthcdihients It is appreciated that the mechansm for increasing the piessure of the Water that is redirected to the device of the present invention so that it can be ietintroduced into a closed water suppy may vary, with one example. being an electric pump The present inventfon s therefore primarily directed at the control means that activate and deactivate the pressire increasing means of the devce when water is redirected to the device from the type of water-saving devicesuch:aS those mertiened in the background Qf i.n'entFon.

Figure 1 shows a preferred ernbpdinient of the control means 1 of the present invention The control means 1 comprises a housing 2 that is preferaNy L' or T' shaped and has an inlet 3, an outlet 4 and an aperture 5 The inlet 3 is in alignment with the aperture 5 but not with the outlet 4 When the control means I is installed in a water supply system, which is essentially a closed system As will be described later, the inlet 3 is connected in fluid communication with diverted water ouUet of a: water-saving device:5Q that when water below a.pre-determined temperature is diverted from the' water outlet (eg. hot tap) it' arrives, at the control means. I via the.

inlet. 3 The outlet 4 is connected. in fluid communication wit the means for increasing the water pressure (not shown'). so that,. Once activated, the means for increasing the water pressure causes an increase in the water pressure of the diverted water that enters control means via the inlet 3 One example of a suitable means for increasing the water pressure is a I2volt electric water pump, although other alternatives will become apoarent on consideration of the: present invention.

The'. aperture 5, which is located in the wall of the housing that faces.

the inlet 3 provides an egress from the closed system and is preferably open to the atmosphere As wifi be explained further below, the provision of an egress from the closed system facilitates' th.e initial movement. O.f the. piston within the.co'ntroj means..

A pistcn. 6 is pr�vided Mthin the housing 2 Qfthe contro:i means 1. n the present embodiment the piston: 6. w hich can slide within the housing 2, serves to help define three chambers within the housing 2 The first chamber 7 provided between the ipset 3 and the pistob The second chambe r 8: ia provided between the piston 6 and the wall of the housing within witch the aperture 5 is located.

In the present embodiment it is important that the piston 6 moves in the same plane as the inlet 3 and the aperture 5 so that the piston 6 can force the air out of the second chamber 8 and redude. its size. By reducing the size of the second chamber 8 the movement of the piston from the closed position to the open position within the housing is accommodated Two O' sealing rings are located in the skirt of the. piston S to facilitate a watertight seal that prevents any fluid communication between the first chanter 7' and the second chamber 8.

A third chamber 9 is provided between the piston 8 and the outlet 4 of the controf means. In the present embodiment the piston does not move iii the same plane as the third chamber 9 The piston 6 is provided with an internal conduit 11, which provides a route of fluid communication between the first chamber 7 and the third chamber 9 when the piston is in an open position The shape of the conduit, which is dogIegged, is such that the flow of water into the conduit applies a directional force to the piston before: it exits the conduIt ii intO the third chamber 9, thus ensuring that the piston 6 stays in the open position for as lông as wE.terficws into; the: control means I The piston is in the open position when the inlet a and the: outFet:4 Of the control means are in flUid commutation via the conduit 1.1 of the piston 6 When the piston 6 is in the closed position the flow of water from the inlet 3 to the outlet is prevented by the piston body because the conduit outiet terminates at the wall of the housing 2 rather than in the third chamber 9.

A spring 12 is provided to flute that the piston 6 defaults towards: the closed posdon where no water flows through the control means The piston 6 is provided with a sealing projection Ba that is positioned ia:, line with the aperture 5 so that when the piston is in the open position the sealing projébtiOh can ctWsr' the apeUre 5 átl� ptewht fluid from eákihg but tf th.' control means I via the aperture 5' It wiU be apprected that alternative arrangements.. . cUba pistQfl witNn the hcushig are pessibte. provided. th$: piston performs. its primary rote of controlling the fluid communicationE between the first and third, Chambers.

Alternative means can be e:nvisaged for biasing the. pistOn 6 of the control means towards the closed position may bausec.

A mcro switch 13 is provided adjacent to the housing 2 The micro : switch 13. operates the means far increasing the water pressure (not shown) so as to: turn it on and off. The micro switch 13. is provided wit,. h an arm 14 that is pivotably mo:untecj. on the iricro switch I 3:80 a S to: turn the swIthh On and off.

A first magnet 15 is located st th. a end of the arm 14 qr: a second magnet 16.: is located. on the ptton 6.. The magnes: I 5 and 1:6: are Qrteflted SQ that their poles both point in the woe direction.. In this way the magnets.

attract. one another when. they are in: offset from one another, but repel One another when they are forced into close proximity with one another As the piston magne.t:16 is. not free to move away from the, switch magnet 1.5, when the piston 6 is: moved into the open position, it is the. switch magnet 15 that is physically repelled The repulsion of the switch magnet 15 operates the arm 14 thereby operating the micro sMAtch 13.

Alternative mechanisms can be envisaged for operating a switc:h to the means for increasing the water pressure when the piston moved.

T e c.peratron of the control means 1, of Figure 1 will, now be described in more detaiL Th:e.device of the present inventbn, of wh'iàh the control neans are in important part, is installed on the redirected (or saved) water line that is itself connected between a first junction with the main water supply system, which:j. provided by's water saving apparatus, and a Second junctori"with the main water supply system, which is:: the point, where any diverted, water is re-introduced in to the main water supply' system.

The operation of the control means, and consequently the device, commences when a hot water outlet of the water supply system is opened If the water' is at or above (in the case of a hot tap) a p:redetermined temperature the water outlet will operate. as: normal and allOw the' water to pass through the thermally actuated diverier valve of the plreviously mentioned' water$aving apparatus and, :xit:thas.ystem. itt the case Whets the Water outlet is a hot tap, for example, any Water arriving at the water outlet that IS below the requwed temperature wdl be dwerted to the water saving hne by the therma)Iy actuated diverier vàlya Jt:j envisaged that a suitably calibrated thermatly actu:ated diverter :vIye QOUId be used tQ ensure the water exiting a coki oi4lct is star below a predeterniined temperature.

Itis. the flow of this diverted w*terinto the control means I that forces the piston 6 towards the open posftion wherein the diverted water can pass into the thIrd chamber 9 and out oftheoutlet 4. The movement ofthe piston 6 from the dosed position to the open position forces the air out of the second chamber:8 Via:apedure 5. By allawing a preliminary fldw: but at the contrOl means add, Closed system to.atm.bsphëre via the aperture 5 it: j pcssible to create a flow in the diverted water line which causes the piston B to rapidly move from the closed posffion to the open position thus bringing the piston magnet 16 and the swiich magnet 1.5. into opposition with one anothe'r The repulshia force creàtéd between the two magnets fortes the. switch magnet 15' and the arm 14 to which ft is attached to move thua operating the micro switch and turnin,g on. an electric water pump.

Once. the pump is switched on it wHI continue to pump the diverted water back into the main water supply system for as long as the' w"ter continues: to be diverted by the thermal, diverter valve. The flow of diverted water through. the control means I via the.conduit 11 ensure.s that the piston 6 remaS in the open. positk:n. As long the piston $ remains in the open position the magnets continue to repel oneanother and the micro switch stays switched on, Once water at or above the, pro-determined temperaturE: arrivós at the thermally activated diverter valve.,, the valve, will opErate to allow the water to tth.wt Outlet. As.3: resUlt oftheflS.i'.c.f' water to the control means via the. saved water line Will eventually: cease thus allowing the piston 6 to return to th closed: position under the: action of the spring 12. As:ffj.: pistOn' retUrns to its defa.ult.position. it separates.the piston magnet lan the. switch itä:net thus aflôwii1 tiw arm 14 tci movS and swftch off the micro switch I 3 The water pup will then turn off.

As the piston 6 moves back to the closed position it causes air to be tfraYdn into. thesecord chamber if Via: the apertureS..

Th*. Slight delay in the deactivatibh of the water pump alsO creates. a small vacuum in the saved water line It has been discovered that this small vacuum in the saved water line assists the water flow at the subsequent tap opening when water is redirected It is understood that this creates a very small initiai flow cycle, which helps some thermally activated thvSe i valves (such as the water-saving apparatus described in International patent application no. PCT/GB2OO8iOO289). to rise and Open their ports, th&&)y allowing diverted waterlo flow intO the saved water line.

The. above described arrangement is such that, once a vvater outlet (e g a hot tap) has been opened, the whole process of water saving fully automated arid does not require iny further action by the user ThUs the device of the present invention is installed with a water-saving.devibe, such as the one described in PCT/AU2004i00041 5 the whole process operates seärnlessly.

In alternative arrangement of the control means 1, the apertureS may feed a water storage tank, which is preferably open to the atmospnere rather than simply venting directly to atmosphere In this way any water that might leak around the piston 6 is captured. As already described, the U sealing rings. lOwe provided to pçevent the flow of: water from the first. chamber 7 into the seôond chamber 8..

As already described the control means forms part of a device for introducing redirected fluids, such as water, back into a closed system, such as the water supply system of a building for example Figures 2 and 3 illustrate, different: system arrangements that utiiis:e the cc.ntrol. mean.s and/or deVice of the present nve.ntion.

All of the systems shown in figures 2 and 3 have the standard components. of a.standard watersupply. system, which wfl be identified using the same ftference numerals.

Each cf the figures showa wE.ter supply system with. a.water heater 20 which. is by the mains. water supply PIPe 21. Once water from the thains.

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water suppIy pipe 21 enters the: syste::ni it is prevented from returning by a non-return valve 22. A junction is provided after the.nonreturn valve 22 where the rifls Water supply pipe spIits into two' with one pipe catrying cold Water 0 e the cold water pipe 23) and one pipe feeding the watei heater 20 (i e the heater supply pipe 24) j The qpl� water pipe 23 js directly:cOflnected to the yariO.us cold water outlets of the system, which include for example cold water taps 25, W C : cistern 26, washing mAchine.27, and show er uhits 28a and ft The cOld water taps 25, which are used as a source cf drinking water, are isolated from the other cold water outlets mentioned above by a nonreturn valve 29 This prevents contamination ofthe drinking water supply The water heater 20 supplies. heated water to the hot water outlets via.

the hot water pipe 30 Typical hot water outlets supplied by the hot water pipe Include hot Water taps.1. and shcWer unitS 28a and 28b.

As already deschbed, in order t. prex'eht the loss of pId: waterthrough the hot water cutlets 31 a watersaving device 32 is installed betwe.en the. hot water pipe 30 and each hot water outlet 31 The diverted water out let of each water-saving device 32 is connected to a saved water return pipe 33 In figure 2 the saved water return pipe 33 is provided with the control means 1 and an electric water pUmp 34. Thö water pump 34 j: connected. to the control ms.rt I by wifing:35 so that it q.n be operated by the control means 1.. As already described once a flow of water is. diverted from the water-saving apparatus 32 to the control means via the saved water return pipe 33 the control means 1 operates the electric water pump 34, which in turn increases the pressure of the water reaching the junction between the saved water return pipe 33 and the he ter supply pip.e.24.

It will be appreciated that because the pressure of the water in the saved water return pipe 33 is increased after the pump 34 the water will force its way back. in to the heater supplypipe: 24 thus allowing it to heated for subsequent.delivery to a hot water outlef 31 In aider to prevent the mains water in the heater supply pipe 24 from entering:: the saved water pipe 33 a non-return valve 36 is provided.

Figure 3 shows an alternative system arrangement wherein, rather than, using an electric water pump 34 pump the wát.O.r bäck in' to heater *i i' $cqpI pipe 24, the thverted wa.r is pumped to a storage: tank 37. The.

storage tank 37, which s preferably a pressure storage tank, is then con n. ect.ed via a stored water return pipe:38 to the cold water.tppiy pipe 23 at jUnction after that non$etu.tn Valve 29 sO. that back cofltan*ihtion of the drinking:ater u��ly is. prevented.

: in tetrofit or new build situatiOns. so as to make the pipe work: less intrusive, the storage tank 37 and the return pipe 38 could be fitted within the confines *:f. the roof space, alternatively the pipe 38 may be fitted under the floor of the dweliing : In order to prevent the:stotge tank 37 from being sUcked enh.pty, thus.

allowing air into the system, a very simple low level stop valve (such as a stafldard W/C cistern stop valve in reyerse) may be incorporated. Thu in anticipation of the very unlikely event of the storage tank 37 becoming over full an pv&flow pipe with an. incorporated pressure/none return VEUVe may be fitted -similar t that used in all. standard domestic Water systema The overflow could easily be routed to any outside water barrel, or water holding receptacle, with an attached warning not to be used for human consumption It is appreciated that, rather than re-introducing the water into the cold water supply pipe 23, the: saved wafer from storage tank 37 coUld also be diverted directly to a W C cistern for flushing only Although this is not considered' the preferred arrangement, in some. retrofit situatIon's It could save on pipe touting and plumbing time.

Although the Dresent invention is mainly described from the position of preventing cold water leaving a water supply system via a hot water outlet, it is envisaged that the present invention could also be employed in arrangements where. hot water Ieavinç a water supply system via a cold water outlet:is'.to be prevented.

Although the present invention is described with reference to water and water supply systems it is envisaged that the present invention may be usefully employed to. save fluidè in otherfluid supply. systems.

Claims (10)

1. cLAIMS.1.. A method of rSucing water wastage in a water supply system by re-circulating water that reaches a water outlet Until such time: that the watet reaching:säd WtEr o'Utet IS: at a predetermined temperature, s:ai niethtd.comprising: determining the temperature çf the water supplying the watë,r outlet and diverting the: W.aterto a recirculation conduit. until. the. water reaches the,: predetemrThed ten perature; d'recir:g the diverted water 1:0 psu increasing means and.increasing the: pressure ofthe diverted water abcve the:: pressure:01 the water supply system:; re-introd:uc.in.g the diverted water back into the water Supply system...
2. 2. The: method of claim 1, Wherein the �ressure increas ng nieä s are activated by control means that.are actuated by the flow of the dN,erted Mater;
3. 3. A fluid actuated control means Or a device for introducing redirected fluid, such as water, back into a closed ystem, said device having a pressure increasing, means that. increases the. fluid pressure of the: redirected fluid above the fluid pressure of the closed system so that the redirected fluid can be re-intrcdUced into said closed system; Said control means comprising: a housing having. a. first, chamber with an inlet connectable to: a source.of redirected, fluid, a second chamber with an outlet that IS: :OEfl to atmospheric: pressure, and a third chamber with an outlet connectable to said pressure incrOäsing means: a piston.rec, ived within the: housing, said piston being.movez..:ble' from a default closed position to an open position by redirected fluid entering the first chamber via the inlet, and whereby in the closed: pOsitiOn fl:uid communication between the first and third chambers is prevented and in the open position fluid communication between the first and third chambers is permitted;' ard *switdh means for activätihg a. pressure. jncreas 1 ng means when the piston moves to the open position and deactivating said pressure increasing rne.ns:* when the. piston rnovesto the dosed po&tion.
4. 4. The control means of claim 3, wherein the piston is received within the housing so as to define a wail of the first chamber and a wall of the second cham'br.
5. 5. The control means of claim, 3 or 4,. wherein the outlet of the second chamber vents to the atmosphere.
6. 6. The control means Of claim.3 o 4 Wherein the outlet of the second chamber feeds into a storage tank
7. 7. The: control mean.s of any of Sims. 3 to 6, wherein the switch means comprise a switch that is mechanically activated by the movement of the piston from the. closed position to:'the open' position.
8. 8. The control means of: claim:7 wherein the switch means compñse a first magnet located on the switch and a second magnet located on the piston and whereby the movement of the piston. to the open. position forces the first and second magnets into close proximity which in turn operates the switch
9. 9. The: control means of any of claims: 3 to 8, further comprising resilient biasing means that default the piston to the closed position
10. 10. A device for introducing redir.cted fluid, suc.h as water, hack i:nto a closed system, said device having a pressure increasin.g means that increases the fluid pressure of the redirected fluid above the fILud pressure of the, closed.systen.: so that the. fluid can be re-introduced into said closed system, said device having a control means that is actuated by the redirected flUid. i4I1. The device of claim 10, wherein the control means comprises:' a hous.ihg having a first. chamber with an inlet connectable, to a source of redirected fluid', a second chamber with an outlet that: is open to atmosphe tic pressure,. and a third chamber With an outlet connectable t said pressure increasing means; a piston received with!r* fli. housing, said piston being m:oveàble from..a dCfa.ult closed position to an open' position by redirected flu:id entering the first chamber via the inlet, and whereby in the closed, position fluid communication between the first and third chambers is prevented and in the open position fluid communication between the first and, thir cham ers i.s permitted:; .:and switch means for activating a. pressure increasing means when the' piston moves to the open position and1 deactivating said preSsufe. increasing.means when the piston moves to the closed position.12. The device of claim 10 0th, wherein said control means' is a' control means..acccrding to any of claims. 3 to 9..t3, The device of cthim 1.0, 11 or 12, wherein the pressure increasing means comprises an electric pump.14. A water supply system dpted, to prevent the wastage of waterty re-circulating water that reaches the an water outlet until such time that the Water reaching. SEid water outlet, is of a. predetermined temperature, said system comprising: a device for introducing redirected fluid back into the water supply system at a higher' fluid pressure than the water supply system1 said device having a c,o.ntrol means that is actuated by the redirected fluid;.a thermally actuated diverter valve which is, located at a jUnction between a water supply, a water outletand Mid device; and.a conduit between the device and point at which the water is re-introduced into the system..15. The system of claim 14,. whereIn said control w.eans is the control means according to any of claims' 3 to 9.16. The system of claim 15, wherein:the Water is outlet is a hot water outlet and wherébyany water that reachës:the buflet that is belOw a pred*rmined temperature is redirected.17. the system of claim 15 or 16, wherein the conduit is arrangcd to re introduce the water into the system upstream of the hot water supply.18. The system of claim 15 or 16, wherein the conduit is artanged tO re-introduce the water into the system downstream of aU of the drhking water outlets in the system, 19. The system of claim 18, further comprising a nonreturn valve to prevent re-introduced water exiting thc. system via a drinking water outlet.20. The' method of claim I or 2, wherei.n a device according to fl of claim 10,. 1 I 12' Or 13 is used to increase the prössure of the water.