GB2194317A - Instantaneous water heaters - Google Patents

Instantaneous water heaters Download PDF

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Publication number
GB2194317A
GB2194317A GB08706458A GB8706458A GB2194317A GB 2194317 A GB2194317 A GB 2194317A GB 08706458 A GB08706458 A GB 08706458A GB 8706458 A GB8706458 A GB 8706458A GB 2194317 A GB2194317 A GB 2194317A
Authority
GB
United Kingdom
Prior art keywords
water
water heater
temperature
heater
flow
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.)
Granted
Application number
GB08706458A
Other versions
GB8706458D0 (en
GB2194317B (en
Inventor
Alan James Currall
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Redring Electric Ltd
Original Assignee
Redring Electric Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Redring Electric Ltd filed Critical Redring Electric Ltd
Publication of GB8706458D0 publication Critical patent/GB8706458D0/en
Publication of GB2194317A publication Critical patent/GB2194317A/en
Application granted granted Critical
Publication of GB2194317B publication Critical patent/GB2194317B/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

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
    • F24H15/20—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
    • F24H15/20—Control of fluid heaters characterised by control inputs
    • F24H15/238—Flow rate
    • 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
    • F24H15/281—Input from user
    • 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
    • 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
    • F24H15/395—Information to users, e.g. alarms
    • 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
    • F24H15/40—Control of fluid heaters characterised by the type of controllers
    • F24H15/414—Control of fluid heaters characterised by the type of controllers using electronic processing, e.g. computer-based
    • 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
    • F24H9/25—Arrangement or mounting of control or safety devices of remote control devices or control-panels
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00—Control of temperature
    • G05D23/19—Control of temperature characterised by the use of electric means
    • G05D23/1917—Control of temperature characterised by the use of electric means using digital means
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00—Control of temperature
    • G05D23/19—Control of temperature characterised by the use of electric means
    • G05D23/20—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature
    • G05D23/24—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature the sensing element having a resistance varying with temperature, e.g. a thermistor

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)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Computer Hardware Design (AREA)
  • Control Of Temperature (AREA)

Abstract

An instantaneous water heater incorporates a flow sensitive device 9 positioned to monitor the inlet water flow, and a flow control valve 10, operable in response to changes in flow monitored by the flow sensitive device, to restore the flow rate to a set value. By this means, the outlet temperature of the water can be maintained approximately constant which is important when, for example, the heater is used with a shower unit and variations in the rate of water flowing to the heater occur when taps in another part of the building are opened. <IMAGE>

Description

SPECIFICATION Instantaneous water heaters This invention relates to so-called instantaneous water heaters, that is to say heaters designed to heat water, either electrically or by means of a gas burner, as it is flowing through the heater, and is primarily concerned with such water heaters designed for use in shower units.
One difficulty which is experienced with such heaters as constructed hitherto is that variations in the rate of water flowing through the heater, as may occur, for example, as a result of taps being opened in another part of the building, can cause the temperature of the outlet water to alter. Accordingly it has previously been proposed to sense the outlet water temperature and adjust the heating means accordingly. Such a control system, however, suffers from the disadvantage that it does not react to a change in flow rate until it is manifested as a change in temperature at the outlet, and the error therefore persists until the change in power can propagate through the heater.
An object of the present invention is to provide an instantaneous water heater employing an alternative form of control system by which this disadvantage is avoided.
According to the invention an instantaneous water heater incorporates a flow sensitive device positioned to monitor the inlet water flow, control means responsive to the flow sensitive device, and a flow control valve controlled by the control means in a manner which tends to maintain the flow rate of the water through the heater substantially at a set value, and hence maintain the outlet temperature of the water approximately constant.
The invention relies on the fact that the outlet temperature is related to the flow rate, and it has been found that with a water heater in accordance with the invention, utilising a fixed output heating means, which may be gas or electrically powered, a very rapid response is obtained, making it possible to maintain the outlet water temperature electrically to within +0.5"C, changes in islet water pressure, caused by opening taps in other parts of the building, have little effect on the set temperature.
Preferably means are provided for enabling a user to adjust the outlet temperature of the water to a desired value, a visual display device conveniently being located adjacent the manual control to give an indication of the outlet water temperature.
The visual display can, for example, take the form of a series of L.E.D's arranged to light up in sequence as the water temperature increases.
The control valve is conveniently operated automatically, for example by means of an electric motor drive responsive to the output of the control means, which is conveniently in the form of a microprocessor; the latter can then also control the water temperature visual display.
In the case of a water heater for a shower unit, the heater may be associated with a manual control panel accessible within the shower area, the heating means, the flow sensitive device, and the control valve being associated with part of the water flow path outside the shower area. This has the advantage that only electrical connections, and not both electrical and water connections, need to be brought to the control panel.
A temperature sensitive device may be arranged to monitor the outlet water temperature, and to generate an output signal for automatically de-energising the heating means in the event of an excessive temperature rise caused, for example, by some malfunction or failure of the control system.
One embodiment of the invention will now be described by way of example with reference to the accompanying drawing which represents diagrammatically a control arrangement for an instantaneous electric water heater in accordance with the invention, utilised in a shower unit.
The heater comprises a main housing 1 located outside the shower cubicle and comprising a heater tank 2 containing electric heating elements 3, 4, and connected to an inlet pipe 5 and an outlet pipe 6. In use cold water is admitted into the heater tank 2 through the inlet pipe 5, and passes via the outlet pipe 6 to a spray unit 7 within the shower cubicle.
The inlet pipe 5 has fitted to it a solenoidactuated on-off valve 8, a flow sensitive device 9, and a control valve 10.
The heater also comprises a control unit 11, which may be accommodated within the housing 1 or in a separate enclosure, the control unit being in the form of a microprocessor 12.
Electric relays 13, 14 actuated by suitable relay drives 15, 16 in response to outputs of the microprocessor 12 are arranged to connect both elements, during normal operation of the heater, to a mains electric supply, giving a power output of approximately 8kW.
On a wall within the shower cubicle there is fitted a manual control panel 17 linked to the control unit 11 and having a series of touch button controls 18 to 21 which provide inputs to the microprocessor 12. Thus the button 18 initiates the start/stop routines, controlling the opening and closure of the on-off valve 8, so as to start or stop the flow of water through the heater and also the energisation and deenergisation of the heating elements 3, 4; the buttons 19, 20 serve to increase or decrease the water outlet temperature, and the operation of the button 21 switches off the heating element 3 whilst leaving the element 4 switched on, as will subsequently be de scribed.
In use of the shower, the flow sensitive device 9 monitors the flow of water within the inlet pipe 5, and feeds a signal to the microprocessor 12 through an interface circuit 22. The microprocessor, in turn, controls the control valve 10 through a motor drive 23, so adjusting the flow of water in the sense and by an amount such as to maintain the water outlet temperature approximately cosntant at the value set by the manual control panel 17.
Such an arrangement gives an almost immediate response to variations in water pressure and hence to the flow of water at the inlet to the heater, and by suitably programming the microprocessor it has been found possible to maintain the outlet water temperature to within f0.5"C of the set value.
When the inlet water temperature is unusually high, for example during summer months, and a relatively low outlet water temperature is required, this may be achieved by actuating the control button 21 as previously described this causing the opening-of a relay 13 thereby switching off the heating element 3, the remaining element 4 providing a power output of approximately 5kW. A microprocessor-controlled light may be arranged to operate when switching to lower power is recommended, if manual switching to this condition has not already been effected.
The manual control panel 17 conveniently carries an indicator shown at 25 for providing a simultaneous indication of the outlet water temperature and the user set temperature.
This comprises, for example a row of L.E.D's connected to outputs from the microprocessor 12.
Although the microprocessor 12 and control valve 10 serves to maintain the outlet water temperature approximately constant, as aforesaid, within normal flow rate limits, the inlet water pressure may in some instances drop by an exessive amount, beyond that at which the control unit 17 and valve 10 can provide an adequate degree of control, thus causing the outlet water temperature to rise.There is accordingly provided a temperature-sensitive device 26, for example in the form of a thermistor, located downstream of the heating elements 3, 4, and connected to the microprocessor, which is arranged to switch off the heating elements 3, 4 and possibly also close the on-off valve 8 in the event that the outlet water temperature attains a maximum "safe" value, for examle 56"C. In addition, an overtemperature switch is conveniently provided, as at 24, for cutting out the heating elements in the event of an excessive temperature rise caused, for example, by failure of the control system.
The heater may incorporate an audible indicator, as at 27, arranged to sound a warning in the event of such a temperature rise occurring.
The design of control above described has the further advantage that remote control is achieved without the need for water connec tions to be brought to the manual control panel 17. Moreover only low voltage electrical connections need to be made to the control panel, as all the control elements of the heater are controlled through the microprocessor 12, the need for mains electrical supplies to enter the shower area being avoided.
Although the shower heater above de scribed makes use of electrical heating ele ments for heating the water it will be appreci ated that the invention could also have appli cation to gas heated shower units.

Claims (15)

1. An instantaneous water heater including a flow sensitive device positioned to monitor water flow through an inlet of the heater, con trol means responsive to said flow sensitive device and a flow control valve operated by said control means in a manner which tends to maintain the flow rate of the water from the inlet to an outlet of the heater substan tially at a set value and hence maintains the outlet temperature of the water approximately constant.
2; A water heater as claimed in Claim 1 wherein means are provided to enable a user to adjust the outlet temperature of the water to a desired value.
3. A water heater as claimed in Claim 1 or 2 wherein a device is provided to give an indication of the outlet water temperature.
4. A water heater as claimed in Claim 3 wherein said device has a visual display.
5. A water heater as claimed in Claim 4 wherein said visual display device is a series of light emitting diodes arranged to light up in sequence as the water temperature increases.
6. A water heater as claimed in any preced ing claim wherein said control valve is gener ated electrically.
7. A water heater as claimed in Claim 6 wherein said control valve is operated by an electric motor drive responsive to the output of the control means.
8. A water heater as claimed in any preced ing claim wherein said control means is a mi croprocessor.
9. A water heater as claimed in Claim 8 wherein said microprocessor controls a visual display device which gives an indication of the water temperature.
10. A water heater as claimed in any pre ceding claim used in a shower unit wherein the control valve is operated by a manual con trol panel accessible within the shower area, the heating means, the flow sensitive device and the control valve being associated with part of the water flow path outside the shower area thus ensuring that only low vol tage electrical connections are brought to the control panel.
11. A water heater as claimed in any preceding claim wherein a temperature sensitive device is arranged to monitor the outlet water temperature.
12. A water heater as claimed in Claim 11 wherein the temperature sensitive device generates an output signal which automatically de-energises the heating means in the event of an excessive temperature rise.
13. A water heater as claimed in any preceding claim wherein said control means is used to energise one of a plurality of heating elements which heat the water.
14. A water heater as claimed in Claim 13 wherein the number of heating elements used is automatically decreased when the input water temperature reaches an unusually high temperature.
15. A water heater as hereinbefore described and represented in the accompanying drawing.
GB8706458A 1986-08-29 1987-03-18 Instantaneous water heaters Expired - Lifetime GB2194317B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB868620996A GB8620996D0 (en) 1986-08-29 1986-08-29 Instantaneous water heaters

Publications (3)

Publication Number Publication Date
GB8706458D0 GB8706458D0 (en) 1987-04-23
GB2194317A true GB2194317A (en) 1988-03-02
GB2194317B GB2194317B (en) 1990-11-14

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Family Applications (2)

Application Number Title Priority Date Filing Date
GB868620996A Pending GB8620996D0 (en) 1986-08-29 1986-08-29 Instantaneous water heaters
GB8706458A Expired - Lifetime GB2194317B (en) 1986-08-29 1987-03-18 Instantaneous water heaters

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GB868620996A Pending GB8620996D0 (en) 1986-08-29 1986-08-29 Instantaneous water heaters

Country Status (1)

Country Link
GB (2) GB8620996D0 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2280014A (en) * 1993-07-16 1995-01-18 Triton Plc Electric instantaneous water heater
GB2298031A (en) * 1995-02-17 1996-08-21 Guang Dong Zhongnan Kosing Ele Gas-fired water heater with remote adjustment
CN102705990A (en) * 2012-07-05 2012-10-03 沁园集团股份有限公司 Balancing device with adjustable water level

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB369440A (en) * 1930-12-18 1932-03-24 Askania Werke Ag Improvements in gas heated liquid heaters
GB1468166A (en) * 1973-06-11 1977-03-23 Cona Ltd Automatic beverage-making apparatus
GB2015779A (en) * 1978-02-24 1979-09-12 Bosch Gmbh Robert Automatic control of fuel flow to ic engines
GB2069726A (en) * 1980-02-14 1981-08-26 Lovelock J E Fluid flow control apparatus and method
GB1597350A (en) * 1976-12-24 1981-09-03 Beringer Hydraulik Gmbh Hydraulic control means
GB2113813A (en) * 1982-01-26 1983-08-10 Scovill Inc Electric coffee maker

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB369440A (en) * 1930-12-18 1932-03-24 Askania Werke Ag Improvements in gas heated liquid heaters
GB1468166A (en) * 1973-06-11 1977-03-23 Cona Ltd Automatic beverage-making apparatus
GB1597350A (en) * 1976-12-24 1981-09-03 Beringer Hydraulik Gmbh Hydraulic control means
GB2015779A (en) * 1978-02-24 1979-09-12 Bosch Gmbh Robert Automatic control of fuel flow to ic engines
GB2069726A (en) * 1980-02-14 1981-08-26 Lovelock J E Fluid flow control apparatus and method
GB2113813A (en) * 1982-01-26 1983-08-10 Scovill Inc Electric coffee maker

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2280014A (en) * 1993-07-16 1995-01-18 Triton Plc Electric instantaneous water heater
GB2280014B (en) * 1993-07-16 1997-04-30 Triton Plc Water heaters
GB2298031A (en) * 1995-02-17 1996-08-21 Guang Dong Zhongnan Kosing Ele Gas-fired water heater with remote adjustment
CN102705990A (en) * 2012-07-05 2012-10-03 沁园集团股份有限公司 Balancing device with adjustable water level

Also Published As

Publication number Publication date
GB8706458D0 (en) 1987-04-23
GB2194317B (en) 1990-11-14
GB8620996D0 (en) 1986-10-08

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Legal Events

Date Code Title Description
PE20 Patent expired after termination of 20 years

Effective date: 20070317