EP3869118A1 - Elektrischer wassererhitzer - Google Patents

Elektrischer wassererhitzer Download PDF

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Publication number
EP3869118A1
EP3869118A1 EP21158608.6A EP21158608A EP3869118A1 EP 3869118 A1 EP3869118 A1 EP 3869118A1 EP 21158608 A EP21158608 A EP 21158608A EP 3869118 A1 EP3869118 A1 EP 3869118A1
Authority
EP
European Patent Office
Prior art keywords
heating
temperature limiter
water
safety temperature
water heater
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Withdrawn
Application number
EP21158608.6A
Other languages
English (en)
French (fr)
Inventor
Marián Má ik
Du an Necas
Branislav Slivka
Ale Kurfürst
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.)
Vaillant GmbH
Protherm Production sro
Original Assignee
Vaillant GmbH
Protherm Production sro
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 Vaillant GmbH, Protherm Production sro filed Critical Vaillant GmbH
Publication of EP3869118A1 publication Critical patent/EP3869118A1/de
Withdrawn legal-status Critical Current

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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
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/18—Water-storage heaters
    • F24H1/20—Water-storage heaters with immersed heating elements, e.g. electric elements or furnace tubes
    • F24H1/201—Water-storage heaters with immersed heating elements, e.g. electric elements or furnace tubes using electric energy supply
    • F24H1/202—Water-storage heaters with immersed heating elements, e.g. electric elements or furnace tubes using electric energy supply with resistances
    • 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
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/10—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium
    • F24H1/12—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium in which the water is kept separate from the heating medium
    • F24H1/124—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium in which the water is kept separate from the heating medium using fluid fuel
    • 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
    • F24H15/132—Preventing the operation of water heaters with low water levels, e.g. dry-firing
    • 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
    • F24H15/223—Temperature of the water in the water storage tank
    • 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
    • F24H9/00—Details
    • F24H9/18—Arrangement or mounting of grates or heating means
    • F24H9/1809—Arrangement or mounting of grates or heating means for water heaters
    • F24H9/1818—Arrangement or mounting of electric heating means
    • 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
    • F24H9/2021—Storage 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
    • F24H15/12—Preventing or detecting fluid leakage
    • 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

Definitions

  • the invention relates to an electric water heater with several heating elements and with a safety temperature limiter, for use in a closed - loop water heating system.
  • Electric water heaters are devices in which electric heating elements are used for water heating, said electric heating elements are in contact with the heated water during heating.
  • backup heater is connected to a closed-loop water heating system with a cold water inlet and with a hot water outlet.
  • a common requirement for electric water heaters is the variability of the performance of the electric water heater and the heating of water of a certain volume, with a requested temperature. Performance variability is most often ensured by means of an electric water heater with a heating block equipped with several heating elements, in which the electrical supply can be switched to either individual or all heating elements. This connection can be made manually, for example optionally by not connecting all the heating elements to the power supply or by using a terminal block with so-called jumpers, it being possible to activate certain combinations of heating elements by means of a heater controller.
  • thermosensors For the purpose of regulating the temperature of the heated fluid, suitably placed temperature sensors and various thermostats with a safety function are used.
  • an electric water heater generally has an electric heating block located in a tank with a certain volume of water, the heating block being mounted in a flange arranged on top of the tank. Furthermore, the electric water heater has a safety temperature limiter which is connected to the electrical contacts for switching the heating elements.
  • the safety temperature limiter is usually composed of a temperature sensor and a fuse made of solder.
  • the temperature sensor is made in the form of a bimetallic switch and is set in such a way that it opens at a preset temperature. If the temperature sensor cools down over time, the contact will close again.
  • the fuse from the fusion solder melts at a higher melting temperature, the so-called critical temperature.
  • capillary temperature limiter which uses a pressure system operating on the principle of liquid expansion. It consists of an ampule with a liquid, a capillary tube and a membrane. After raising the temperature on the ampule, the liquid in the capillary tube expands and causes the membrane to move. This movement activates the latch switch, which causes the switch contacts to open or close.
  • the switching principle is therefore exclusively mechanical, in contrast to the version with bimetallic and fuse, and in certain circumstances can be considered more reliable.
  • a crucial condition for reliable operation for all types of safety temperature limiters is the correct sensing of the water temperature in the tank with which the sensor is in contact.
  • dry fire refers to a situation where a heating block is connected to a source of electrical energy to provide heating, while there is no or a very small volume of water in the tank of the electric heater. In this state, the heating elements can be damaged relatively easily by overheating.
  • the document US 2017059208 A1 discloses a water heater having a tank with at least one heating element.
  • the non-invasive water level sensor is arranged in connection with the volume of water containing the volume of the tank. If the signal received from the sensor indicates that at least one heating element is immersed in water, energy is supplied to the heating element. If the signal indicates that at least one heating element is not immersed in water, the supply of energy to the heating element is prevented.
  • This solution is expensive and presupposes a horizontal arrangement of the heating elements in the electric water heater.
  • the document EP 3037741 B1 describes in detail a method for preventing dry fire in electric instantaneous water heaters equipped with a safety temperature limiter by means of a controller evaluating switching times.
  • the fuse with the solder in the safety temperature limiter melts.
  • the fuse with the solder must then be replaced so that the electric heater can be operated again.
  • the document CN 101014219 A discloses an electric heating element with automatic temperature control inside a water tank and with dry fire prevention.
  • the U-shaped heating coil is connected in parallel to the temperature limiter and is connected to the temperature sensor directly by a tight contact or indirectly via an optional thermally conductive bracket.
  • the correct indication of the measured temperature is a condition for the correct function of the safety temperature limiter, as is clear from the state of the art.
  • the present invention relates to an electric water heater with variable heating output, in which several heating elements are located.
  • the aim of the present technical solution is to avoid erroneous or late evaluation of the switching temperature when switching the powers in the electric water heater and to design such an arrangement of the electric water heater in which effective protection against dry fire is achieved with little effort.
  • the temperature sensor in the safety temperature limiter evaluates its temperature with sufficient accuracy.
  • the temperature sensor of the temperature limiter is immersed in the water by means of a thermally conductive housing and the heat transfer from the heating elements to the water and from the water to the sensor takes place mainly by convection and conduction.
  • the reaction time of the switch is up to 60 seconds, regardless of the switching temperature set value, since the heat transfer from the heating elements to the sensor takes place mainly by radiation.
  • the consequence of this long reaction time is that the heating elements, which are in the heating state, can reach a temperature of more than 800°C. In a short time, the surface of the water heater reaches a temperature of over 300°C, which is undesirable.
  • the solution consist of the safety temperature limiter sensor placement in the area with the assumed maximum water temperature, i.e. between the heating elements in the middle of the tank.
  • all heating elements are connected to the safety temperature limiter sensor by a suitable thermally conductive means. This will ensure that heat from the heated elements is applied to the sensor in a conductive manner, even in the dry fire state (without the presence of water).
  • thermoly conductive means conveys the temperature information inside the tank correctly.
  • FIGs 1 , 2a , 2b show a heating block 1 which is used to heat water in an electric backup water heater for a heat pump heating system.
  • Figure 3 shows the heating block 1, which is fixed to the electric backup heater flange and the flange is connected in a waterproof manner with the tank. The both - cold water inlet 10 and hot water outlet 20 are placed on the backup heater flange.
  • the electric backup heater with variable heating output for the heat pump heating system is equipped with a heating block 1 composed of at least two heating elements 2, 2'. In the illustrated example, 6 pieces of the heating element are connected and they extend into different depths of the water tank.
  • the safety temperature limiter 3 is located in the water tank such a way, that it is surrounded by the heating elements 2, 2'.
  • a capillary safety temperature limiter 3 is used, which is electrically connected with an electric terminal contacts of the electric backup heater (not shown in the drawings).
  • the temperature sensing element is an ampule containing a fluid, the fluid increasing its pressure as the temperature sensed by the ampule increases. This pressure is transmitted by the capillary to the switch.
  • the switch When the temperature rises above the set temperature (for example 98°C), the switch causes the contacts to open and disconnects the power supply to the heating elements.
  • the contacts open and block the heating even if the hydraulic system of the sensor leaks or if the measured temperature falls below -20°C.
  • the contacts will close again if the sensed temperature is lower than the set temperature (98°C) and the reset button is pressed. To ensure greater safety, the professional intervention of a service technician and the exclusion of the possibility of a reset is recommended.
  • the safety temperature limiter 3 is housed in a water tank in a metal housing which conducts heat well and the temperature sensor of the safety temperature limiter 3 can sense the water temperature in this way.
  • All heating elements 2, 2' are thermally connected to the safety temperature limiter 3 by a suitable thermally conductive means, in the example of embodiment it is a metal thermally conductive strip 4.
  • a first circular section 5 of a connecting strip 4 made of a well thermally conductive metal material (e.g. copper) is tightly slid onto the metal housing of the safety temperature limiter 3, and the first circular section 5 is fastened to the second circular section 6 by means of several transverse sections 7.
  • a well thermally conductive metal material e.g. copper
  • the third, substantially circular section 8 of the connecting strip 4 is connected to the second circular section 6 of the connecting strip 4 by several transverse sections 7 of the connecting strip 4 so that the heating elements 2, 2' are located in the space between the second and third circular sections 6, 8 and each of the heating elements 2, 2' is in contact with at least one transverse section 7 and/or with at least one circular section 6, 8 of thermally conductive strip 4.
  • the third, substantially circular section 8 of the connecting strip 4 surrounds the heating elements 2, 2' so that the connecting strip 4 fixes the heating elements 2, 2' and prevents their displacement, which could occur due to deformation of the metallic material of the heating elements 2, 2' during operation.
  • the thermally conductive connecting strip 4 is immersed in water during normal operation and must be at such a distance from the flange as to ensure a touch connection with each, i.e. also with the shortest heating element.
  • the heat from each heated heating element is conducted sufficiently quickly and reliably to the safety temperature limiter 3 by conduction.
  • the thermally connecting strip being composed of three circular sections 5, 6, 8 and seven transverse sections 7 causes only a negligible pressure loss in the heating system.
  • the sufficiently strong thermally connecting strip 4 keeps the heating elements 2, 2' in the original (assembly) position and serves as a reinforcement preventing their displacement during normal deformation changes caused by operation.
  • a preferred embodiment of the electric heater comprises a deflector 9 arranged at the water inlet 10, which evenly directs the cold water supplied to the electric heater to the heating elements 2, 2' and restricts direct cold water flow to the safety temperature limiter 3 (the deflector arrangement is shown in Fig. 2b ).
  • the arrangement of the heating elements and the design of the thermally conductive means as well as the type of safety temperature limiter may differ in other embodiments of the described technical solution, but the contact connection of each heating element to the thermally conductive means must be maintained to ensure conductive heat transfer to the safety temperature limiter sensor in a dry fire state.

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  • 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)
  • Heat-Pump Type And Storage Water Heaters (AREA)
EP21158608.6A 2020-02-24 2021-02-23 Elektrischer wassererhitzer Withdrawn EP3869118A1 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SK212020 2020-02-24

Publications (1)

Publication Number Publication Date
EP3869118A1 true EP3869118A1 (de) 2021-08-25

Family

ID=74701407

Family Applications (1)

Application Number Title Priority Date Filing Date
EP21158608.6A Withdrawn EP3869118A1 (de) 2020-02-24 2021-02-23 Elektrischer wassererhitzer

Country Status (1)

Country Link
EP (1) EP3869118A1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4290155A1 (de) 2022-06-06 2023-12-13 Vaillant GmbH Elektrischer ptc-heizer
EP4325137A1 (de) 2022-08-15 2024-02-21 Vaillant GmbH Modularer elektrischer ptc-heizer

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2479587A (en) * 1944-09-30 1949-08-23 Electro Therm Electric heater
US2606271A (en) * 1949-07-14 1952-08-05 American Instr Co Inc Electric heater and thermostatic control means therefor
DE1454731A1 (de) * 1962-09-15 1969-09-04 Vaillant Joh Kg Elektrischer Heisswasserspeicher
FR2525294A1 (fr) * 1982-04-19 1983-10-21 Rheem Radi Spa Diffuseur d'eau froide pour l'entree d'appareils rechauffeurs d'eau
DE19545155A1 (de) * 1994-12-05 1996-06-13 Gerhard Glanz Heizpatrone
CN101014219A (zh) 2007-02-05 2007-08-08 常熟市新力电子器件厂 具有自动温度控制和防止干烧的电加热管
US20170059208A1 (en) 2015-08-26 2017-03-02 Rheem Manufacturing Company Electric water heater having dry fire protection capability
EP3037741B1 (de) 2014-12-23 2018-03-14 Vaillant GmbH Verfahren zur vermeidung von trockenbrand bei elektrischen durchlauferhitzern

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2479587A (en) * 1944-09-30 1949-08-23 Electro Therm Electric heater
US2606271A (en) * 1949-07-14 1952-08-05 American Instr Co Inc Electric heater and thermostatic control means therefor
DE1454731A1 (de) * 1962-09-15 1969-09-04 Vaillant Joh Kg Elektrischer Heisswasserspeicher
FR2525294A1 (fr) * 1982-04-19 1983-10-21 Rheem Radi Spa Diffuseur d'eau froide pour l'entree d'appareils rechauffeurs d'eau
DE19545155A1 (de) * 1994-12-05 1996-06-13 Gerhard Glanz Heizpatrone
CN101014219A (zh) 2007-02-05 2007-08-08 常熟市新力电子器件厂 具有自动温度控制和防止干烧的电加热管
EP3037741B1 (de) 2014-12-23 2018-03-14 Vaillant GmbH Verfahren zur vermeidung von trockenbrand bei elektrischen durchlauferhitzern
US20170059208A1 (en) 2015-08-26 2017-03-02 Rheem Manufacturing Company Electric water heater having dry fire protection capability

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4290155A1 (de) 2022-06-06 2023-12-13 Vaillant GmbH Elektrischer ptc-heizer
EP4325137A1 (de) 2022-08-15 2024-02-21 Vaillant GmbH Modularer elektrischer ptc-heizer

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