GB2442801A

GB2442801A - Electric shower assembly

Info

Publication number: GB2442801A
Application number: GB0620209A
Authority: GB
Inventors: Adrian Farrant
Original assignee: COTSWOLD AUTOFLO Ltd
Current assignee: COTSWOLD AUTOFLO Ltd
Priority date: 2006-10-12
Filing date: 2006-10-12
Publication date: 2008-04-16
Also published as: GB0620209D0

Abstract

An electric shower assembly comprises a shower head (figure 3, 55) for creating a spray of water and a pump 41 for pumping water from a water tank (figure 1, 29) to the shower head. A first electric heater 31 is adapted to heat water in the water tank to a predetermined temperature, while a second electric heater is adapted to heat water in the flowpath between the pump and the shower head to a temperature 10 above the predetermined temperature. Control means (figure 3, 57) is provided to energise either the first 31 or the second electric heater such that only one of the first and second electric heaters is energised at any time. The first electric heater 31 may be an immersion heater. The second electric heater can be incorporated into the control means (figure 3, 57) and may comprise an instantaneous water heater. A heat exchanger (figure 1, 21) and a digital thermostat 47 may also be included.

Description

ELECTRIC SHOWER ASSEMBLY

This invention relates to an electric shower assembly, and is particularly concerned with an electric shower assembly having low current consumption.

In order to produce an adequate flow of water of about 4 litres per minute or more at a suitable temperature of about 40 to 44 degrees Celsius, an electric shower must consume at least 7.2 kW, conventionally at about 230 Volts.

A problem with such electric showers is that they cannot readily be employed in emergency or other situations where only conventional mains power is available at 13 Amps. It would be useful, for example, to be able to quickly and easily install electric showers in emergency situations where decontamination, for example, is required and only conventional mains power or a low-power generator (for example 3 kW) is available. It would also be useful to install showers in domestic or commercial premises (for example, hotels) where only conventional mains power is available. However, at present this is not possible.

It is therefore an object of the present invention to provide an electric shower assembly which overcomes, or at least ameliorates, the above problems.

According to the present invention there is provided an electric shower assembly comprising: a shower head for creating a spray of water; a pump for pumping water from a water tank to the shower head; a first electric heater adapted to heat water in the water tank to a predetermined temperature; a second electric heater adapted to heat water in the flowpath between the pump and the shower head to a temperature above the predetermined temperature; and control means adapted to energise either the first or the second electric heater such that only one of the first and second electric heaters is energised at any time.

The first and second electric heaters may each have a power rating of substantially 3 kW.

The first electric heater may be an immersion heater, while the second electric heater may be an instantaneous water heater.

The first electric heater may be arranged in a lower region of the water tank.

The water tank may have an outlet for water flowing to the pump arranged in an upper region of the tank. The outlet may incorporate a filter.

A thermostat may be provided for controlling the temperature of water in the tank to the predetermined temperature. The thermostat may comprise a digital thermostat. The thermostat may control the temperature of the water in the tank to substantially 32 degrees Celsius, for example 32 degrees Celsius +1-0.5 degrees.

The shower assembly may include an on-off switch for activating the shower whereby, when water is flowing to the shower head the second electric heater is energised and when water is not flowing to the shower head the first electric heater is energised to heat the water in the tank to the predetermined temperature.

The shower assembly may include a heat exchanger for transferring heat from heated water flowing out of a waste outlet from the shower to water flowing into the water tank. The heat exchanger may be arranged beneath a support sheet for a user of the shower assembly. The heat exchanger may incorporate a tortuous path for the incoming and for the outgoing water. The tortuous path may be arranged in an array of upright walls supporting the support sheet. The tortuous path for the outgoing water may be defined by a plurality of apertures formed through the upright walls. The tortuous path for incoming water may be defined by a conduit, such as a flexible conduit, passing through the upright walls. The paths for the incoming and outgoing water may be arranged such that the liquids are flowing in counterfiow over at least a part of their respective flowpaths.

For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, byway of example, to the accompanying drawings in which: Figure 1 is a diagrammatic perspective view of a lower region of an electric shower assembly according to the present invention; Figure 2 is a rear view of the electric shower assembly shown in Figure 1; and Figure 3 is a perspective view of the shower assembly shown in Figures 1 and 2.

Figure 1 shows the lower part of an electric shower assembly according to the present invention. The shower assembly comprises a base I which is made of polypropylene having a thickness of about 20 mm, a width of about 764 mm and a depth of about 962 mm. Grooves are formed in the base 1 to receive other components of the shower assembly and to facilitate mounting such other components to the base in a secure and watertight manner.

Walls 3 and 5 are mounted at the edge of the base 1 along the front and one side of the base and together form part of a shower tray. The walls 3 and 5 are relatively low. A shower screen 7 is mounted around the other side and towards the rear of the base so as to complete the shower tray and to form two sides of a shower enclosure. The other two sides of the shower enclosure may be formed by a curtain, if desired.

Within the shower tray there is provided an array of upright walls 9 which extend front-and-back and transversely within the tray. The walls 9 support a sheet 11 which is mounted within the shower tray on which a user is supported. The walls 9 enable the sheet 11 to support a significant load, such as a user weighing up to 170 kg or more. The sheet 11 is at a level below the upper edge of the shower tray walls 3 and 5. A waste outlet 13 is provided in the region of the centre of the sheet 11 and may be removable for cleaning purposes.

The various components of the shower assembly may be secured together by plastic welding.

The upright walls 9 within the shower tray are provided with apertures 15 which define a tortuous path through the array of walls from an inlet 17 for incoming water to an outlet 19. The upright walls 9 are also provided with apertures in which a flexible tubular conduit 21 is arranged, again following a tortuous path, this time from the waste outlet 13 to an outlet coupling 23 formed in a side of the shower tray. The conduit 21 passes through the path defined within the shower tray for the incoming water to form a heat exchanger whereby heat from the waste water is transferred to the incoming water to provide pre-heating of the incoming water and to recover heat from the waste. The two paths are arranged such that the outgoing waste runs in counterfiow to the incoming water so far as this is practicable. The conduit 21 is relatively narrow and restricts the flow rate of water through it. This ensures maximum transfer of heat from the outfiowing hot waste water. The restricted flow rate also results in a relatively slow and laminar flow into a holding tank 29, minimising disturbance of the water already within the holding tank.

The inlet 17 for fresh water flowing into the heat exchanger flows from a cold water storage tank 25 which is provided with an inlet 27, while water flowing out of the outlet 19 flows into the holding tank 29 which, as with most of the plastics components, may be made of polypropylene. The water feed to the inlet 27 may be either a mains water supply or may be gravity fed from a separate reservoir.

The inlet 27 may incorporate a valve, such as a float valve, to prevent over-filling of the water storage tank 25. The storage tank 25 and the holding tank 29 are mounted on the base 1 at the rear thereof.

The holding tank is provided with an electric immersion heater 31 (for example of 3 kW power) having an element extending about 100 mm above the bottom of the holding tank 29, with a probe 33 for a thermostat (not shown in Figure 1) and with an outlet 35 for heated water, which outlet may extend about 50 mm below the surface of the water in the holding tank so as to withdraw hot water from the holding tank which has risen to the upper region of the holding tank.

Withdrawing hot water from the upper region of the holding tank 29 causes water from below to rise and in turn to be replaced in the lower region of the holding tank by relatively cold water from the incoming water path through the array of walls 9 within the shower tray. The heater 31 may include a thermal cut-out to prevent overheating and is energised only when the shower is not in use in order to maintain power consumption at a low level. The thermostat probe 33 may be adapted for use with a digital thermostat (to be described in more detail hereinafter) and may include a thermistor or like electrical sensor.

Figure 2 is a rear view of the electric shower assembly according to the present invention and includes a power inlet 37 for a 230 Volt, 13 Amp supply which leads to a lockable isolator switch 39 for controlling the supply of power to components of the shower assembly. Power is conducted from the isolator switch 39 to an electrical enclosure 43. A pump 41 is connected to the electrical enclosure 43 and draws heated water from the upper region of the holding tank 29 through water outlet 35 and sends it through a conduit 45 which, as will be explained in more detail hereinafter, is connected to a shower head (not shown in Figure 2). As shown in Figure 2, the water outlet 35 may include a filter 51 to prevent blockages within the pump 41 and shower control unit (described in more detail hereinafter). The electrical enclosure 43 includes a number of RCD/MCB devices (residual current devices/miniature circuit breakers) to protect the user against electrical problems and provides a supply of electricity to the immersion heater 31 located in the lower region of the holding tank 29, to a digital thermostat 47 and, by way of conduit 49, to shower controls which are not shown in Figure 2. Digital thermostat 47 is connected to the thermostat probe 33 in the holding tank 29.

Figure 3 shows the shower assembly from the front and includes a riser rail 53 for adjusting the height of a shower head 55. The shower head is connected to an outlet of a shower control unit 57 which incorporates an instantaneous water heating unit (for example a 3 kW instantaneous water heater) and is provided with a flow adjusting control 59 and an on-off switch 61, such as a solenoid valve.

In use of the shower assembly according to the present invention, the shower control unit 57 energises the immersion heater 31 to heat the water in the holding tank 29. The temperature of the water in the holding tank is monitored and controlled by the thermostat 47 and probe 33 to a predetermined temperature of substantially 32 degrees Celsius +1-0.5 degrees (or any other suitable temperature). Once the temperature of the water in the holding tank 29 has reached the predetermined temperature the shower assembly is ready for use. The holding tank 29 is made of polypropylene material which provides sufficient thermal insulation to maintain the water within an acceptable range from the predetermined temperature (for example 0.5 degrees Celsius) for some time. However, should the temperature of the water within the holding tank 29 fall below an acceptable level the immersion heater 31 is activated to heat the water to the predetermined temperature.

A user can then enter and use the shower assembly. When the on-off switch 61 is actuated to initiate a flow of water, the pump 41 is activated and electrical power is diverted from the immersion heater 31 to the instantaneous water heater within the shower control unit. That is, the immersion heater 31 is de-energised and the instantaneous water heater is energised in order to maintain the power consumption at a low level.

Water at the predetermined temperature is drawn by the pump 41 from the holding tank 29 and conveyed to the shower control unit 57 where the instantaneous water heater raises the temperature of the water to about 41 to 44 degrees Celsius at a flow rate of about 4.5 litres/minute. The hot water from the instantaneous water heater is conveyed to and out of the shower head 55 to provide the user with a shower of water at a temperature which is generally considered to be ideal for the purpose. The capacity of the holding tank 29 is such that a flow of hot water can be maintained for about 8 minutes, although the size of the holding tank and the flow rate can be varied if required. The flow rate can also be varied to adjust the temperature of the hot water exiting the shower head. A lower flow rate will raise the temperature of the water, while a higher flow rate will lower its temperature.

Water falling into the shower tray exits by way of the waste outlet 13 and flows through the conduit 21 which passes through the upright walls 9 within the base of the tray so as to heat inflowing water to the holding tank 29.

Once the user has finished with the shower, the on-off switch 61 is activated to de-energise the pump 41 and to transfer electrical power from the instantaneous water heater within the shower control unit 57 to the immersion heater 31 within the holding tank 29 in order to return the water in the holding tank to the predetermined temperature so that another user can have a shower.

Claims

1. An electric shower assembly comprising: a shower head for creating a spray of water; a pump for pumping water from a water tank to the shower head; a first electric heater adapted to heat water in the water tank to a predetermined temperature; a second electric heater adapted to heat water in the flowpath between the pump and the shower head to a temperature above the predetermined temperature; and control means adapted to energise either the first or the second electric heater such that only one of the first and second electric heaters is energised at any S... time. * . S...

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2. A shower assembly as claimed in claim 1, wherein the first and second S..... electric heaters each have a power rating of substantially 3 kW. *5S** -12-

3. A shower assembly as claimed in claim I or 2, wherein the first electric heater is an immersion heater, while the second electric heater is an instantaneous water heater.

4. A shower assembly as claimed in any preceding claim, wherein the first electric heater is arranged in a lower region of the water tank.

5. A shower assembly as claimed in any preceding claim, wherein the water tank has an outlet for water flowing to the pump arranged in an upper region of the tank.

6. A shower assembly as claimed in claim 5, wherein the outlet incorporates a filter.

7. A shower assembly as claimed in any preceding claim, wherein a thermostat is provided for controlling the temperature of water in the tank to the predetermined temperature. S... * . S...

8. A shower assembly as claimed in claim 7, wherein the thermostat :hh1 20 comprises a digital thermostat. 0.5.

9. A shower assembly as claimed in claim 7 or 8, wherein the thermostat controls the temperature of the water in the tank to substantially 32 degrees Celsius.

10. A shower assembly as claimed in claim 9, wherein the thermostat controls the temperature of the water in the tank to 32 degrees Celsius +1-0.5 degrees.

11. A shower assembly as claimed in any preceding claim and including an on-off switch for activating the shower whereby, when water is flowing to the shower head the second electric heater is energised and when water is not flowing to the shower head the first electric heater is energised to heat the water in the tank to the predetermined temperature.

12. A shower assembly as claimed in any preceding claim and including a heat exchanger for transferring heat from heated water flowing out of a waste outlet from the shower to water flowing into the water tank.

13. A shower assembly as claimed in claim 12, wherein the heat exchanger is arranged beneath a support sheet for a user of the shower assembly.

14. A shower assembly as claimed in claim 13, wherein the heat exchanger incorporates a tortuous path for the incoming and for the outgoing water. *** * * I...

15. A shower assembly as claimed in claim 14, wherein the tortuous path is arranged in an array of upright walls supporting the support sheet.

****** * * -14 -

16. A shower assembly as claimed in claim 15, wherein the tortuous path for the outgoing water is defined by a plurality of apertures formed through the upright walls.

17. A shower assembly as claimed in claim 15 or 16, wherein the tortuous path for incoming water is defined by a conduit, such as a flexible conduit, passing through the upright walls.

18. A shower assembly as claimed in claim 18, wherein the conduit comprises a flexible conduit.

19. Ashowerassemblyasclaimed in anyoneofclaims l4to 18,whereinthe paths for the incoming and outgoing water are arranged such that the liquids are flowing in counterfiow over at least a part of their respective flowpaths.

20. An electric shower assembly substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings. * .** * * S... **S * . ***.

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