GB2319831A - Safety system for instantaneous water heaters - Google Patents
Safety system for instantaneous water heaters Download PDFInfo
- Publication number
- GB2319831A GB2319831A GB9725354A GB9725354A GB2319831A GB 2319831 A GB2319831 A GB 2319831A GB 9725354 A GB9725354 A GB 9725354A GB 9725354 A GB9725354 A GB 9725354A GB 2319831 A GB2319831 A GB 2319831A
- Authority
- GB
- United Kingdom
- Prior art keywords
- water
- heating element
- heater
- switch
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 107
- 238000010438 heat treatment Methods 0.000 claims description 69
- 238000001816 cooling Methods 0.000 claims description 18
- 239000008236 heating water Substances 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 7
- 230000001276 controlling effect Effects 0.000 description 4
- 230000006378 damage Effects 0.000 description 3
- 208000027418 Wounds and injury Diseases 0.000 description 2
- 208000014674 injury Diseases 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 230000004913 activation Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H9/00—Details
- F24H9/20—Arrangement or mounting of control or safety devices
- F24H9/2007—Arrangement or mounting of control or safety devices for water heaters
- F24H9/2014—Arrangement or mounting of control or safety devices for water heaters using electrical energy supply
- F24H9/2028—Continuous-flow heaters
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H15/00—Control of fluid heaters
- F24H15/10—Control of fluid heaters characterised by the purpose of the control
- F24H15/128—Preventing overheating
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H15/00—Control of fluid heaters
- F24H15/10—Control of fluid heaters characterised by the purpose of the control
- F24H15/174—Supplying heated water with desired temperature or desired range of temperature
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H15/00—Control of fluid heaters
- F24H15/10—Control of fluid heaters characterised by the purpose of the control
- F24H15/184—Preventing harm to users from exposure to heated water, e.g. scalding
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H15/00—Control of fluid heaters
- F24H15/20—Control of fluid heaters characterised by control inputs
- F24H15/212—Temperature of the water
- F24H15/219—Temperature of the water after heating
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H15/00—Control of fluid heaters
- F24H15/30—Control of fluid heaters characterised by control outputs; characterised by the components to be controlled
- F24H15/305—Control of valves
- F24H15/31—Control of valves of valves having only one inlet port and one outlet port, e.g. flow rate regulating valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H15/00—Control of fluid heaters
- F24H15/30—Control of fluid heaters characterised by control outputs; characterised by the components to be controlled
- F24H15/355—Control of heat-generating means in heaters
- F24H15/37—Control of heat-generating means in heaters of electric heaters
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fluid Mechanics (AREA)
- Bathtubs, Showers, And Their Attachments (AREA)
Abstract
A control system for an instantaneous water heater 20 comprises allowing a flow of cold water to remove the latent heat from a heater element 22 after the power to the element has been turned off, thereby obviating the possibility of "overheated" water scalding a subsequent user. The temperature of the outlet water flow 14 is detected using a thermal cut-off switch 30. This switch controls a solenoid valve 18 which in turn controls water flow. After the power to the element 22 is terminated water continues to flow until it reaches the cut-out temperature of the switch 30. The switch closes the solenoid 18 which stops the water flow. The system is suitable for use in a shower.
Description
WATER HEATER CONTROL SYSTEM
The present invention relates to a water heater, and more particularly to an instantaneous water heater, and a control system for a water heater.
Background to the Invention
Instantaneous water heaters are extremely attractive to users and particularly suitable for showers because water is heated virtually instantaneously after the heater is turned on by a user. To achieve such rapid heating, a high powered electric heater or heat exchanger must be used.
Since most instantaneous water heaters such as showers operate with an electric heater the background to the invention will now be described with reference to an electric heater.
An electric heater typically comprises a heating element.
When a shower including an electric heater is turned on, the heating element is heated to a temperature greater than 100"C. The element is then cooled by the passage of water either directly past the heating element or past a heat exchanger associated with the element. The effect of this cooling is to control the external temperature of the heating element and to heat the water.
A problem arises however when the shower is turned off.
Both the water supply and the current supply to the heating element are cut off. Unfortunately, however, the heating element will still be extremely hot and will continue to heat any water in the vicinity of the heating element.
This is not problematical under most conditions since the heating element and surrounding water will cool down within a fairly short period of time, e.g. five minutes.
However, if the shower is reused before the cooling element has had a chance to cool down, for example, after a very short period of time e.g. one minute, then the next user receives a stream of very hot, possibly boiling water.
This problem, arises quite frequently, for example, in the household of a large family or at a sports club.
Thus, although the instantaneous water heaters can be attractive, it presents a safety hazard under certain conditions.
It is therefore an object of the present invention to provide a water heater such as an instantaneous water heater eg a shower in which the likelihood of danger to a user is reduced.
Summary of the invention The present invention provides a control system for an instantaneous water heater comprising:
a first switch for controlling power supplied to a heating element for heating water; and
means for cooling the heating element after the power supplied to the heating element is cut off.
In a further aspect there is provided an instantaneous water heater comprising:
a heating element for heating water;
a first switch for controlling power supplied to the heating element; and
means for cooling the heating element after the power supplied to it is cut off.
Preferably, the means for cooling comprise means for passing water over the heating element after the power supplied to the heating element is cut off.
Preferably, the means for cooling comprises a water flow control means and a second switch arranged to control power supplied to the water flow control means so that water is passed over the heating element to cool the heating element.
Preferably, the heating element is cooled to a predetermined temperature after the power supply to the heating element is cut off.
Preferably, the means for cooling comprises means for sensing the temperature of the heated water so that the heating element is cooled until the temperature of the heated water falls below a pre-determined temperature.
Preferably, the means for cooling comprises a thermal cutout switch.
Preferably, the water flow control means is a solenoid valve.
In a further aspect there is provided, a method of controlling the water flow in an instantaneous water heater comprising a heating element for heating water comprising the step of:
cooling the heating element after the power supplied to the heating element has been cut off.
Preferably, the method comprises the step of
passing water over the heating element after the power supplied to the heating element has been cut off.
Preferably, the heating element is cooled until the temperature of the heating water falls below a pre set level.
Preferably, the method comprises using the control system according to the invention.
Preferably, an instantaneous water heater for a shower is provided comprising a heating element, solenoid valve operated inlet means for supplying water to be heated to the heating element and outlet means for passage of the heated water to the shower, which means for controlling the heating element and said solenoid valve means and including thermal cut out means having a predetermined temperature cut off level situated in thermal contact with the water outlet means to sense the temperature of the outlet water from the heating element, in which said thermal cut out means is operatively connected to the solenoid valve means to continue the supply of water to the heating element until the outlet water temperature falls below the level set by the said thermal cut out means.
Preferably, a control system for an electrically heated shower is provided, the control system comprising electrical switch means connected to supply electrical power to an electric water heater, said switch means being operable to open a solenoid valve being operable to control the supply of water to the electric water heater; and including thermal cut out means operable to detect the temperature of heated outlet water from the electric water heater and being operable to maintain open the solenoid valve until the sensed water temperature falls below a predetermined level.
In a preferred embodiment, a phased shut down control system for an instantaneous electric shower is provided which causes the inlet water to continue to run after the power is turned off in order to ensure that the electric heating element is cooled to a temperature where it cannot create scalding water to a second user.
Brief description of the drawings
The present invention will now be described, by way of example, with reference to the accompanying drawings.
Figure 1 shows schematically a water heating system including a control system in accordance with the invention.
Figure 2 shows schematically a shower including a control system in accordance with the present invention.
Although, the control system of the present invention is described with reference to an electric shower, it will be apparent to a person skilled in the art that the control system could be used with any other apparatus which provides an instantaneous supply of water. For example, the control system of the present invention could be used with a tap.
Detailed description of a preferred embodiment
In Figure 1, a water heater 1 comprises a power supply 2, a first switch 3 which controls water and power respectively to water flow valve 4 and heater 5. On activation of first switch 3, water 6 is passed via water flow control valve to heater 5 and heated producing hot water output 7.
Second switch 8 is also activated providing a second route for power to flow from power supply 2 to water flow control valve 4 on the occurrence of certain criteria. The criteria may be the end of a predetermined time period or when heater 5, or preferably hot water output 7, achieves a certain temperature. Sensing means necessary to activate second switch 8 are not shown. When water heater 1 is switched off, first switch 3 is opened and power is no longer supplied to water flow control valve 4 and heater 5 via first switch 3. However, since second switch has been activated power is still supplied to water flow control valve 4. Therefore, water flow control valve 4 remains open and water is supplied to heater 5 until second switch 8 is switched off. Second switch 8 will switch off under predetermined circumstances. This may be the end of a further time period, the temperature of heater element of heater 5 falling below a certain temperature, or, more preferably, the temperature of hot water output 7 falling below a certain temperature. The means for cooling the heater element after water heater 3 is switched off is in this particular embodiment provided by the passage of water over heater 5. The passage of air or other fluid could be used as an alternative.
The sensing means, for example a temperature sensing means, providing a signal to the second switch is typically placed on the hot water output 7 though this is not shown for simplicity. Indeed, the second switch 8 and the sensing means may form an integral component.
A more detailed example is shown in figure 2, in which a shower apparatus 10 comprises a shower outlet 12 which supplies water 14 to a user.
Water enters the shower apparatus 10 via an inlet 16. The inlet 16 is connected to a solenoid valve 18. The solenoid valve 18 is connected to a heater or heat exchange unit 20, where the water is heated by a heating element 22.
In the drawing, the water pipe connections are not shown for the sake of clarity. The direction of water flow, however, is indicated by the arrows.
The heater 20 of the present invention is supplied with electrical power via junction box 24. Again for simplicity only the live L and neutral N connections from the junction box 24 are shown.
A live connection to the heating element 22 is provided by a line 262 via a switch 26. Switch 26 is provided with a control dial 28. The control dial 28 operates in a conventional manner to energise element 22. As the operation of the switch 26 and control dial 28 is well known it will not be described further.
A neutral connection is permanently applied to the heating element 22 and it is therefore the switch 26 which controls the power supply to heating element 22.
A live connection is provided by line 264 via switch 26 to solenoid valve 18. It follows that once switch 26 is closed the solenoid valve will open, allowing water to flow to the heating element 22. The heating element 22 is also instantly activated when the switch 26 is closed. Allowing for the short time for the heating element 22 to warm up, the outlet water 14 will be heated virtually instantaneously. The heating will be maintained as long as switch 26 is open with thermostatic control of the water temperature being provided at the outlet 12.
An override cut-out 220 for the heating element 22 may also be provided in the conventional manner in case the heating element 22 overheats. The cut out will typically be of the one-shot type, which requires resetting by a skilled technician, as the cut-out is normally only operated when the shower is faulty.
In the circuit of the present invention a non-switched live connection is supplied to a thermal cut out 30 on line 266.
The non-switched live connection along line 266 is also supplied to solenoid valve 18 on line 268, when the cut out 30 is closed, thereby supplying a second or alternative live supply to the solenoid valve 18. Thermal cut out 30 effectively acts as a switch supplying power to solenoid valve 18 when a preset condition, in this case temperature of the water, is met.
The operation of the circuit will now be described.
The shower is switched on using the switch 26 and the control dial 28. Thermostatic control of element 22 to maintain the correct temperature is achieved is known manner and thus it is not further described.
When switch 26 is closed with the control dial 28, the live connection line 264 causes the solenoid valve 18 to open, allowing water to flow past element 22.
The water is heated by element 22 to a desired set temperature. The heated water flows past the thermal cut out 30, which is activated when the water reaches a predetermined temperature. The pre-determined temperature 30 can be set fairly low such that cut out 30 will always be activated by the water output from element 22. It could, for example, be a temperature between 25-40"C.
Thus, once the shower has been in use for a few seconds the cut out 30 will be activated and an alternative live supply will be provided to the solenoid valve 18 via line 268.
As a user continues to use the shower the heating element 22 will continue to be heated to its normal (relatively high) operating temperature, while simultaneously being cooled by the flow of outlet water 14.
When the user has finished, switch 26 will be turned off and normally the solenoid valve 18 would be shut because the live connection on line 264 would be cut-off. Power to the shower heating element would then also be cut-off.
However, in the present invention a live connection will still be supplied via line 268 and solenoid valve 18 will remain open. Cold water will continue to flow past heater element 22 and will cool the heating element 22. As the heating element 22 cools, the outlet water 14 also cools until it reaches the cut out temperature of thermal cut out 30. When this temperature is reached, the live connection on line 268 will be cut-off and the solenoid valve 18 will close, thereby shutting off the water supply. By this time the element 22 will have cooled substantially. Therefore, even if a second user enters the shower within a minute or so after shut-off the heating element 22 will not have heated any water immediately adjacent to it to a temperature which might cause damage to the second user.
The water emitted from shower outlet 14 does not have to be hot enough to burn the user to cause injury. If the water is initially hot enough to cause the user to move rapidly away from the shower then an accident may result if the user slips. This may be particularly problematic for elderly or infirm people and for this reason many establishments prefer baths where the water temperature is more easily regulated.
The present invention therefore provides a control system and a water heater which can reduce the likelihood of injury during use.
A shower having the control system of the present invention can be used virtually continuously since the shower is shut off in a phased manner so that cooling of the heating element takes place after the user shuts off the shower.
A preferred embodiment of the phased shut down control system of the present invention is robust since thermal cut outs 30 are extremely reliable even in the extremely hostile environment of a shower cubicle.
The control system of the present invention is also relatively inexpensive, requiring only two additional wires and a thermal cut out attached to the outlet of a heater 20.
Claims (14)
1. A control system for an instantaneous water heater comprising:
a first switch for controlling power supplied to a heating element for heating water; and
means for cooling the heating element after the power supplied to the heating element is cut off.
2. An instantaneous water heater comprising:
a heating element for heating water;
a first switch for controlling power supplied to the heating element; and
means for cooling the heating element after the power supplied to it is cut off.
3. A system or heater according to claim 1 or 2, in which the means for cooling comprise means for passing water over the heating element after the power supplied to the heating element is cut off.
4. A system or heater according to claim 3, in which the means for cooling comprises a water flow control means and a second switch arranged to control power supplied to the water flow control means so that water is passed over the heating element to cool the heating element.
5. A system or heater according to any preceding claim, in which the heating element is cooled to a pre-determined temperature after the power supply to the heating element is cut off.
6. A system or heater according to any preceding claim, in which the means for cooling comprises means for sensing the temperature of the heated water so that the heating element is cooled until the temperature of the heated water falls below a pre-determined temperature.
7. A system or a heater according to claim 6, in which the means for cooling comprises a thermal cut-out switch.
8. A system according to claim 4, 5, 6 or 7, in which the water flow control means is a solenoid valve.
9. A method of controlling the water flow in an instantaneous water heater comprising a heating element for heating water comprising the step of:
cooling the heating element after the power supplied to the heating element has been cut off.
10. A method according to claim 9 comprising the step of
passing water over the heating element after the power supplied to the heating element has been cut off.
11. A method according to claim 9 or 10, in which the heating element is cooled until the temperature of the heating water falls below a pre set level.
12. A method according to claim 9, 10 or 11 comprising the step of using the control system according to any of claims 1 to 9.
13. A control system for a water heater substantially as described herein with reference and/or substantially as illustrated in figure 1 and/or 2.
14. A water heater substantially as described herein with reference and/or substantially as illustrated in figure 1 and/or 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9725354A GB2319831A (en) | 1996-11-30 | 1997-12-01 | Safety system for instantaneous water heaters |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GBGB9625008.9A GB9625008D0 (en) | 1996-11-30 | 1996-11-30 | Delayed shut off system |
| GB9725354A GB2319831A (en) | 1996-11-30 | 1997-12-01 | Safety system for instantaneous water heaters |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9725354D0 GB9725354D0 (en) | 1998-01-28 |
| GB2319831A true GB2319831A (en) | 1998-06-03 |
Family
ID=26310532
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9725354A Withdrawn GB2319831A (en) | 1996-11-30 | 1997-12-01 | Safety system for instantaneous water heaters |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2319831A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2428285A (en) * | 2005-07-12 | 2007-01-24 | Aqualisa Products Ltd | Instantaneous water heater control |
| CN102374661A (en) * | 2010-08-13 | 2012-03-14 | 关隆股份有限公司 | Safety detection method for water heater |
| CN102564517A (en) * | 2010-12-23 | 2012-07-11 | 关隆股份有限公司 | Gas safe supply detecting and compensating method |
| GB2511368A (en) * | 2013-02-28 | 2014-09-03 | Quanduo Hou | Instant electric water heater |
| GB2559236A (en) * | 2016-12-09 | 2018-08-01 | Xiamen Aquasu Electric Shower Co Ltd | A switching device for a instant electric water heater |
| CN112031081A (en) * | 2020-07-17 | 2020-12-04 | 金鹏智能家居有限公司 | Multifunctional shower device |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2090650A (en) * | 1980-12-02 | 1982-07-14 | Triton Aquatherm | Improvements in or relating to fluid flow control devices |
| GB2115912A (en) * | 1982-02-10 | 1983-09-14 | Redring Electric Ltd | Instantaneous water heater for shower unit |
| GB2158926A (en) * | 1984-04-24 | 1985-11-20 | Imi Santon Ltd | Electric flow heater |
| GB2183789A (en) * | 1985-12-10 | 1987-06-10 | Caradon Mira Ltd | Valve |
-
1997
- 1997-12-01 GB GB9725354A patent/GB2319831A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2090650A (en) * | 1980-12-02 | 1982-07-14 | Triton Aquatherm | Improvements in or relating to fluid flow control devices |
| GB2115912A (en) * | 1982-02-10 | 1983-09-14 | Redring Electric Ltd | Instantaneous water heater for shower unit |
| GB2158926A (en) * | 1984-04-24 | 1985-11-20 | Imi Santon Ltd | Electric flow heater |
| GB2183789A (en) * | 1985-12-10 | 1987-06-10 | Caradon Mira Ltd | Valve |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2428285A (en) * | 2005-07-12 | 2007-01-24 | Aqualisa Products Ltd | Instantaneous water heater control |
| GB2428285B (en) * | 2005-07-12 | 2010-03-03 | Aqualisa Products Ltd | Instantaneous water heater |
| CN102374661A (en) * | 2010-08-13 | 2012-03-14 | 关隆股份有限公司 | Safety detection method for water heater |
| CN102374661B (en) * | 2010-08-13 | 2013-09-18 | 关隆股份有限公司 | Safety detection method for water heater |
| CN102564517A (en) * | 2010-12-23 | 2012-07-11 | 关隆股份有限公司 | Gas safe supply detecting and compensating method |
| CN102564517B (en) * | 2010-12-23 | 2015-03-25 | 关隆股份有限公司 | Gas safe supply detecting and compensating method |
| GB2511368A (en) * | 2013-02-28 | 2014-09-03 | Quanduo Hou | Instant electric water heater |
| GB2511368B (en) * | 2013-02-28 | 2016-05-04 | Hou Quanduo | Instant electric water heater |
| GB2559236A (en) * | 2016-12-09 | 2018-08-01 | Xiamen Aquasu Electric Shower Co Ltd | A switching device for a instant electric water heater |
| GB2559236B (en) * | 2016-12-09 | 2019-05-15 | Xiamen Aquasu Electric Shower Co Ltd | A switching device for an instant electric water heater |
| CN112031081A (en) * | 2020-07-17 | 2020-12-04 | 金鹏智能家居有限公司 | Multifunctional shower device |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9725354D0 (en) | 1998-01-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |