GB2298480A

GB2298480A - Shower using stored hot water and instantaneous heating

Info

Publication number: GB2298480A
Application number: GB9602060A
Authority: GB
Inventors: Neville Ian Benson
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-02-11
Filing date: 1996-02-01
Publication date: 1996-09-04
Also published as: GB9502673D0; GB9602060D0

Abstract

Warm water for a shower is normally provided by mixing stored hot water 10 with cold water 11 in a mixing valve 60, but a temperature sensor 20 switches on an electrical instantaneous heater 31, 32 if the temperature of the hot water falls below a certain level. In "electric" mode, the heater is supplied with cold water only, to conserve the remaining hot water, and the user can select at 70 the desired power output of the heater (one element, the other or both) and the output flow rate provided by pump 80. In "normal" mode, the mixing valve controls temperature and flow rate of the warm water. Switching to "electric" mode can be effected manually if desired, rather than waiting for the temperature sensor to respond.

Description

Combined Shower This invention concerns a combined shower unit.

Present shower units provide a choice between either a conventional mixer shower which mixes hot water supplied by a gas boiler or central heating system with cold water, or an electric shower which requires only cold water and heats this to the desired temperature.

Both systems have their advantages and disadvantages. Conventional mixer showers, possibly incorporating a pump to make them into "power showers" allow thermostatic control of temperature and allow a variable flow rate, the two being controlled independently of one-another. However, they generally suffer from their dependence upon water stored in hot water tanks, the hot water often running out whilst a user is having a shower. This is especially so with "power showers" which use large quantities of water to provide their "power" effect.

The solution to this problem is to either plan the shower at least an hour in advance, switching the boiler on to ensure that there is plenty of hot water, or to risk having to have a cold shower. Turning on a boiler in the summer just for a shower is an expensive exercise, the boiler typically having at least up to 90 gallons of water in the hot water tank to allow for a shower which may only require 9 gallons of hot water.

This is clearly unacceptable and electric showers provide a solution, at least in part, to these problems.

Electric showers are capable of instantly providing a continuous supply of hot water. However, because the power output of the shower is constant there cannot be independent control both of water temperature and water flow. Additionally, an electric shower is an inefficient use of resources, wasting energy and money if a user already has hot water waiting to be used, which has been provided by a central heating system.

The present invention overcomes the disadvantages of both systems, and provides the advantages of both systems.

According to the present invention there is provided a shower unit comprising hot and cold water inlets, a temperature sensing arrangement for the hot water inlet, and a heater adapted to operate when the temperature of the water sensed by the arrangement falls below a predetermined level.

By preferentially using any hot water which is available, e.g. any hot water in a hot-water tank heated by a central-heating system, the shower unit usually operates by the mixing of available hot water with cold water from e.g. a rising main or from a water storage tank, optimising the use of available hot water before producing hot water as required..

The heating means operates to heat water when the temperature ofthe inlet hot water falls below a predetermined level.

The shower unit may also comprise switching means such that whilst hot water of at least the predetermined temperature is available at the hot water inlet, such hot water is admitted through the hot water inlet and when such hot water is not available no water is admitted through said inlet and said heating means is used instead to heat the water from the cold water inlet. Such a switch might be operable automatically or manually, for example, to allow the central heating/hot water boiler to concentrate on the central heating function to heat up a cold house in the shortest possible time.

Hence the temperature sensing arrangement and the switching means operate to allow either a "conventional" shower in which the inlet hot water is mixed with the inlet cold water or an electric shower in which inlet cold water is heated by heating means.

By having the heating means cut in when the hot water is not of a sufficient temperature, the system allows one to use any existing hot water before using the heating means to provide the hot water. This is extremely convenient and allows for the most efficient possible use of resources. For example, if one is unsure as to whether or not there is sufficient water for a conventional shower, one need not worry since the combined shower guarantees that there will be sufficient hot water. The present invention obviates the need to plan in advance a shower and, for example in the summer, one may have a shower without having to especially heat e.g. a 90 gallon tank of hot water for a 5 gallon shower thereby saving money, whilst in winter the hot water provided by the central heating may be used.Additionally, by having the switching means switch off the inlet hot water at a predetermined temperature, sufficient hot water may be left for e.g. other domestic uses.

Hence the present invention is both convenient and economical.

The temperature sensing means may be used in conjunction with delay means such that when the unit is initially used the use of the heating means is inhibited for sufficient time to allow any hot water to flow into the hot water inlet and heat the temperature sensing means.

Hence upon the initial use ofthe shower unit, the use ofthe heating means is suppressed for a sufficient length of time to allow hot water from e.g. a hot water tank to reach the shower and heat the temperature sensing means.

The length of inhibition may be set at the time of installation of the shower unit. Hence the length of inhibition may be adjusted to allow for the location of the shower unit which may be for example very near to a hot water tank or which may be on a different floor of a building to a hot water tank.

The shower unit may also be used in conjunction with flow measuring means such that the length of inhibition is affected by the flow rate of water through the hot water inlet. Hence if the flow rate is low the length of inhibition may be increased.

On the other hand, particularly in times of water-usage restrictions, the running of cold water to waste before the hot water flows through from the hot water tank is wasteful of water and it is in any event wasteful of time. The apparatus may then be operated so as to heat the initially cold water so that hot water is instantly available no matter what length of piping runs from the tank, saving both time and water.

The shower unit may be used in conjunction'with flow measuring means such that the flow measuring means prevents the activation of the heating means if the flow rate of water through the hot water inlet is below a predetermined level.

This allows the user ofthe shower unit to have a cold shower by reducing the flow rate of water through the hot water inlet below a predetermined level, e.g. by stopping the flow of inlet hot water, without causing the heating means to be activated.

The shower unit may also comprise mixer means such that when the inlet hot water is being admitted the desired output flow rate and water temperature is controlled by the mixer means.

Hence when the shower is in the "conventional" mode, the output flow rate and temperature may be determined by mixing means which act to mix the hot and cold inlet water.

The mixing means may also comprise a thermostat such that the desired output temperature is stabilised. This means that another person using either the hot or cold water will have a minimal effect upon the temperature of the shower.

The mixer means may be manually controlled.

Hence the user may manually select the output flow rate and temperature of the shower when it is in the conventional mode. The mixer may be a standard "conventional" mixer unit.

The heating means may comprise multiple heating elements.

The heating means may comprise two heating elements.

The heating elements may, for example, be of 3KW and 4.5KW or of 3.5KW and 5.5KW.

The shower unit may also comprise selector means such that the user may select the desired power output of the heating elements.

Hence the user may for example select from a power output of 3KW, 4.5KW and 7.5KW in a shower unit with two heating elements, one being of 3KW and the other of 4.5KW. Alternative power output would be of 3.5, 5.5 and 9KW in a unit with elements of 3.5 and 5.5KW, or 2,3,4,5,6,7 and 9KW in a unit with elements of 2, 3 and 4KW.

The shower unit may also comprise pump means in order to control the output flow rate. In particular, the pump means may be used to increase the output flow rate.

Hence, the pump means may allow the shower to be used as a "power shower", possibly providing an output pressure greater than mains water pressure or the water pressure of a cold water tank..

The shower unit may also comprise selector means such that the user may select a desired output flow rate determined by the pump means.

Hence the user may select between e.g. "normal" and "power shower" modes of operation.

The output flow rate may be linked to the heating means such that when the heating means is used, the power output of the heating means correlates with the output flow rate.

Hence when in "electric" mode, a change in the output flow rate may also result in a change in the power output ofthe heating means and vice-versa. For example, a shower unit may have two heating elements giving three different power outputs and three different settings for the pump. The lowest output of the heating means may be linked to the lowest power level of the pump means, the medium output of the heating means may be linked to the medium power level of the pump means, and the highest power output ofthe heating means may be linked to the highest power level of the pump means. The various power levels of the heating means and the pump means may correlate such that at the different power levels, the output water temperature is approximately equal.Hence not only may different output flow rates be enjoyed in "conventional" mode, but they may also be enjoyed in "electric" mode without a great change in output water temperature.

The shower may also comprise selector means such that a desired temperature of the output water heated by the heating means may be obtained.

The desired temperature may be attained by affecting the output flow rate.

Hence when in electric mode, the output water temperature may be attained by affecting the output flow rate. Hence a shower unit with multiple "power" settings may operate at variable output flow rates and a desired output temperature may be attained by slight changes in the output flow rate, the heating means power output remaining constant. This allows for a shower unit in "electric" mode to provide all the features of a "conventional" shower, namely selectable temperature and flow rate.

The shower unit may also comprise selector means such that the heating of inlet cold water by the heating means may be manually selected.

Hence if a user detects a change in output temperature yet the inlet hot water temperature has not reached the predetermined minimum, heating of inlet cold water and the shutting off of inlet hot water may be manually selected.

The invention will be further apparent from the following description, with reference to the figure of the accompanying drawing, which show, by way of example only, one form of the invention.

Figure 1 shows a combined shower unit.

The shower unit comprises hot water inlet (10), cold water inlet (11), temperature sensing arrangement (20) and heating means (31; 32).

It also comprises switching means (not shown) controlling valves (41; 42; 43; 44). When operating in "conventional" mode, valve 41 is open allowing in hot water and valve 42 is closed. Valve 43 is closed and valve 44 is open, thereby bypassing the heating means (31; 32).

When operating in "electric" mode, valve 41 is closed preventing the entry of any water through the hot water inlet 10 and valve 42 is open, allowing the flow of water from the inlet cold water (11). Valve 43 is open and valve 44 closed, thereby allowing water to pass through the heating means.

The temperature sensing means (20) are used in conjunction with delay means (not shown) such that when the unit is initially used the use of the heating means (31; 32) is inhibited for sufficient time to allow any hot water to flow into the hot water inlet (10) and heat the temperature sensing means (20).

The length of inhibition determined by the delay means (not shown) is set at the time of installation of the shower unit.

Flow measuring means (50) measures the rate of flow of water through the hot water inlet (10) and affects the length of inhibition determined by the delay means (not shown).

The flow measuring means (50) prevents activation of the heating means (31; 32) when the flow rate detected is below a predetermined level. This prevention of the activation of the heating means (31; 32) is achieved by the delay means (not shown) which inhibits the activation and activity of the heating means (31; 32).

Hence a cold shower can be enjoyed either by initially preventing the flow of water through the hot water inlet 10 or by cutting off the flow during a "conventional" shower.

The shower unit also comprises manually controlled mixer means (60) which mixes the hot water from the hot water inlet (10) and the cold water inlet (11) to achieve the desired temperature. The mixer means (60) also allows control of the output flow rate by a flow rate controller (not shown) in order that a desired output flow rate may be achieved in "conventional" mode.

The mixer means (60) also comprises a thermostat (not shown) such that the desired output temperature is stabilised.

The heating means (31; 32) comprises two heating elements (31; 32).

Heating element 31 comprises a 3.5KW element and heating element 32 comprises a 4KW element.

Selector means 70 allow the user to select the desired power output of the heating elements (3.5, 4 and 7.5KW).

The shower unit also comprises pump means 80 in order to control the output flow rate.

Selector means 70 allows the user to select a desired output flow rate (options are "Normal", "Moderate", and "Power").

The output flow rate determined by the pump means (80) is linked to the heating means (31; 32) such that when the heating means (31; 32) is used, the power output of the heating means (31; 32) correlates with the output flow rate.

Hence the lowest ("Normal") output flow rate corresponds to a 3.5KW power output, the medium ("Moderate") flow rate to a 4KW output and the greatest ("Power") flow rate to a 7.5KW output, the correlation being such that an approximately equal output temperature is attained at the various power output and output flow rate levels.

Hence the selector means (70) with the options of "Normal", "Moderate" and "Power" allows a user to select one ofthree output flow rates in "conventional" mode and when in "electric" mode, one of the three output flow rates may be selected, the power output of the heating means (31; 32) correlating to the selected output flow rate such that an approximately equal temperature is attained at the various output levels.

Selector means 70 also allows a desired output temperature of water heated by the heating means (31; 32) to be achieved. This is achieved by altering the output flow rate determined by the pump means (80) whilst maintaining the power output of the heating means (31; 32) at a constant level.

The "electric" mode may be manually selected by selector means 70 which affects the switching means (not shown).

In order to turn off the shower in "conventional" mode, the flow rate controller (not shown) of the mixer means (60) must be set to the "Off' position to prevent any water output, the switch to "electric" mode being prevented by the flow measuring means (50) and delay means (not shown).

In order to turn off the shower in "electric" mode, the flow rate controller (not shown) in the mixer means (60) must be set to the "off" position, thereby resetting the switching means (not shown) to the original "conventional" mode, which in turn results in the resetting of valves 41,42,43 and 44 to the "conventional" mode states.

Additionally, the heating means and pump are switched off and the delay means reset.

Hence as the flow rate controller (not shown) is turned to the "off" position, there will be no change in flow rate or temperature until the "off' position is reached when the shower unit is reset to its "conventional" mode settings and no water output allowed.

Hence whenever the shower unit is turned off, upon its next being used it will be in the "conventional" mode.

Since the selector means (70) are not reset upon the shower unit being switched off, the settings are retained for the next use. The settings for output flow rate and temperature in "electric" mode are obvious at all times and so a user will know what the settings of the shower unit are before switching it on.

It will be appreciated that it is not intended to limit the invention to the above example only, many variations being possible, such as might readily occur to one skilled in the art.

Claims

1. A shower unit comprising hot and cold water inlets, a temperature sensing arrangement for the hot water inlet, and a heater adapted to operate when the temperature of the water sensed by the arrangement falls below a predetermined level.

2. A shower unit according to Claim 1 wherein it also comprises switching means such that whilst hot water of at least the predetermined temperature is available at the hot water inlet, such hot water is admitted through the hot water inlet and when such hot water is not available no water is admitted through said inlet and said heating means is used instead to heat the water from the cold water inlet.

3. A shower unit according to either one of Claims 1 or 2 wherein the temperature sensing means are used in conjunction with delay means such that when the unit is initially used the use of the heating means is inhibited for sufficient time to allow any hot water to flow into the hot water inlet and heat the temperature sensing means.

4. A shower according to Claim 3 wherein the length of inhibition is set at the time of installation of the shower unit.

5. A shower unit according to Claim 3 or 4 used in conjunction with flow measuring means such that the length of inhibition is affected by the flow rate of water through the hot water inlet.

6. A shower unit according to any one of claims 1 to 5, arranged to heat initially cold water from piping from the hot water tank whereby to provide instant hot water without running cold water to waste and to cut out or reduce the heater operation when hot water from the tank reaches the unit.

7. A shower unit according to any one of Claims 1 to 6 used in conjunction with flow measuring means such that the flow measuring means prevents the activation of the heating means if the flow rate of water through the hot water inlet is below a predetermined level.

8. shower unit according to any one of Claims 1 - 6 wherein it also comprises mixer means such that when the inlet hot water is being admitted the desired output flow rate and water temperature is controlled by the mixer means.

9. A shower unit according to Claim 8 wherein the mixer means also comprise a thermostat such that the desired output temperature is stabilised.

10. A shower unit according to either one of Claims 8 and 9 wherein the mixer means are manually controlled.

11. A shower unit according to any one of Claims 1 -10 wherein the heating means comprises multiple heating elements.

12. A shower unit according to Claim 11 wherein the heating means comprises two heating elements.

13. A shower unit according to either one of Claims 11 and 12 wherein it also comprises selector means such that the user may select the desired power output of the heating elements.

14. A shower unit according to any one of Claims 1 - 13 wherein it also comprises pump means in order to control the output flow rate.

15. A shower unit according to Claim 14 wherein it also comprises selector means such that the user may select a desired output flow rate determined by the pump means.

16. A shower unit according to Claim 15 wherein the output flow rate is linked to the heating means such that when the heating means is used, the power output of the heating means correlates with the output flow rate.

17. A shower unit according to any one of Claims 1 - 16 wherein it also comprises selector means such that a desired temperature of the output water heated by the heating means may be obtained.

18. A shower unit according to Claim 17 wherein the desired temperature is attained by affecting the output flow rate.

19. A shower unit according to any one ofthe preceding Claims also comprising selector means such that the heating of inlet cold water by the heating means may be manually selected.