AU2010100920A4 - Water saving device - Google Patents

Description

Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION INNOVATION PATENT Name of Applicant: WATER SAVING INNOVATIONS PTY. LTD. Actual Inventors: HERBERT CLARENCE SPILLER JOHN HAROLD WADE Address for Service: SANDERCOCK & COWIE 180B SLADEN STREET CRANBOURNE VICTORIA 3977 Invention Title: WATER SAVING DEVICE - 1 - - la TITLE: WATER SAVING DEVICE FIELD OF THE INVENTION 5 This invention concerns the recovery of water from the hot water pipe of a domestic hot water system downstream of the hot water heater. BACKGROUND OF THE INVENTION 10 Householders using the reticulation system in a dwelling are familiar with the waste of -2 water which remains in the pipe connecting the tap to the hot water heater when the tap is used intermittently and the water in the pipe cools, for example when using a shower. The warm water runs to waste. While such waste has been accepted in years gone by, water shortages due to drought have caused examination of domestic water use with the 5 intention of making cumulative savings. SUMMARY OF THE INVENTION The method aspect of the invention provides a method of capturing reject water below 10 target temperature in a hot water system comprising connecting a hot water leg to source in a loop, connect pump in loop for intermittent supply, switch on pump when hot water is required for a predetermined warmup period, indication to user when target temperature is reached. 15 The apparatus aspect of the invention provides an assembly for retaining reject water below target temperature in a hot water system, comprising a return leg connectable to the hot water leg thereby establishing a loop for sending cold and then warm water back to the hot water source, a pump in the loop for intermittent operation, a timer for switching the pump off when the loop is delivering water at the target temperature, and 20 signal means for indicating to the user when the loop has reached target temperature. The apparatus aspect further provides a kit of parts for adapting a hot water system to retain water below target temperature comprising a water pump, pipe connections to connect the pump to pipework of an existing hot water leg, a control box containing a 25 relay and a timer and electrical contacts for mains supply, an external switch for activating the pump, and signalling means to indicate when the loop is at target temperature. BRIEF DESCRIPTION OF THE DRAWINGS 30 One embodiment of the invention is now described with reference to the accompanying drawings, in which: -3 Figure 1 is a diagram of a hot water supply in a single storey dwelling. Figure 2 is a diagram of the dwelling in Figure 1 converted to incorporate the invention. 5 Figure 3 is the electrical circuit controlling the pump addition and modification to the hot water supply. DETAILED DESCRIPTION WITH RESPECT TO THE DRAWINGS 10 Referring now to the drawings, a domestic water heater 2 has a boiler 4 with a cold inlet 6 and a hot outlet 8. The cold inlet 6 admits water at mains pressure. The hot water outlet 8 enters wall 10 supplies in series a laundry 12, a washbasin 14, shower 16, and kitchen 18, the kitchen being the last in the series. As soon as the tap 20 is opened to allow flow, the mains pressure feeds hot water along pipe 22. The user allows the initial 15 cold water in pipe 22 to run to waste and it is this waste which the invention seeks to eradicate. The larger the building, the longer the pipe, the greater the volume of rejected water. The period which elapses until water at the hottest operating temperature arrives depends on the ambient temperature of the pipe, the type of boiler which produces the hot water and the presence or absence of thermal insulation. Older larger houses are poor 20 performers and water rejection is high. In Figure 2, the endmost tap 20 which supplies the kitchen sink receives a T-union 24 and return pipe 26 converts feed pipe 22 into a loop. 25 The loop is connected to the inlet of pump 28, the outlet of which is connected to the cold inlet 6, thereby returning the unused hot water to the boiler. The pump is an ULTRACIRC UC-959 which uses about 70 watts and generates 10 Bar. The maximum temperature rating for this pump is higher than the boiler delivery at 45-55 0 C. The pump has an integral one way valve 30 and thermostat. The one way valve ensures that the 30 return leg of the loop is not subject to opposing flow from the boiler. The electrical circuit is shown in Figure 3. A control box 32 is sited in an accessible area -4 such as the laundry. The box houses a 240v transformer 36 which supplies 24v to a relay 38 and a timer 40. The relay and timer are connected in series in the 24v circuit and when the circuit is opened and closed by any one of three switches 42 connected in parallel, the relay connects the pump to 240v and the timer runs for a period selected at 5 installation. The installer selects from a test carried out in winter which shows the period necessary to reach the target temperature at the furthest tap from the hot water source. This may be from 15 seconds to two minutes according to the responsiveness of the boiler, flow rate , etc. The switches 40 may be distributed around the loop so that a user may enter the bathroom and prepare the loop by switching ON. Each switch has an LED 10 light 44 which illuminates while the timer is running. When the timer switches OFF, the light also switches OFF indicating that the loop is circulating water at the required temperature. Regulations require the inclusion of a thermostat. If the water temperature rises unduly, 15 the thermostat turns the pump OFF, however the circuit allows the operator to re-start the pump by operating any of the switches 40. We have found the advantages of the above embodiment to be: 20 1. Neither cold nor warm water escapes from the system as the operator waits for hot water. 2. For rural homes which rely on tank water, the saving may be crucial. 25 It is to be understood that the word "comprising" as used throughout the specification is to be interpreted in its inclusive form, ie. use of the word "comprising" does not exclude the addition of other elements. It is to be understood that various modifications of and/or additions to the invention can 30 be made without departing from the basic nature of the invention. These modifications and/or additions are therefore considered to fall within the scope of the invention.

Claims (5)

1. An assembly for retaining reject water below a target temperature in a hot water system, with a hot water source and a hot water leg, comprising a return leg 5 connectable to the hot water leg thereby establishing a loop for sending cold and then warm water back to the hot water source, a pump in the loop for intermittent operation, a timer for switching the pump off when the loop is delivering water at the target temperature and signal means for indicating to the user when the loop has reached target temperature. 10

2. An assembly as claimed in Claim 1, wherein the signalling means is a light switched by the timer.

3. An assembly as claimed in Claim 2, wherein the timer starts the pump and 15 illuminates the light and stops the pump and cancels the light when the target temperature is reached.

4. An assembly as claimed in Claim 2 or 3, wherein each hot water outlet site has a timer switch for starting the pump and a light to indicate when to draw hot 20 water from the assembly.

5. A kit of parts for adopting a hot water system to retain water below target temperature consisting of a water pump, pipe connections to connect the pump to pipework of an existing hot water leg, a control box containing a relay and a 25 timer and electrical contacts for mains supply, an external switch for activating the pump and signalling means to indicate when the pump is at target temperature,