EP1896917A1 - Heating device for fluids and domestic appliance - Google Patents
Heating device for fluids and domestic applianceInfo
- Publication number
- EP1896917A1 EP1896917A1 EP06724972A EP06724972A EP1896917A1 EP 1896917 A1 EP1896917 A1 EP 1896917A1 EP 06724972 A EP06724972 A EP 06724972A EP 06724972 A EP06724972 A EP 06724972A EP 1896917 A1 EP1896917 A1 EP 1896917A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- heating
- heating element
- heating device
- switching means
- 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- Withdrawn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
Classifications
-
- 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
- G05D23/2401—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 using a heating element as a sensing element
Definitions
- the invention relates to a heating device for fluids, in particular for use in dishwashers, with a heating element whose resistance value is a function of its temperature and which is coupled via a switching means to a power supply, and with a protective device for protecting the heating element against overheating, which is set to operate the switching means in dependence of the temperature of the heating element.
- the invention further relates to a domestic appliance, in particular a dishwasher with devices for washing dishes, with a heating device for heating liquid to be heated, in particular treatment liquid, for. B. rinse liquor.
- Heating elements that are used in heaters for heating fluids can be permanently damaged in a drying cycle of the heater and the boiling over of water.
- household appliances such as Kettles, coffee machines, dishwashers, washing machines, are used, among other things based on thick-film technology electrical resistance heaters as heating elements.
- electrical resistance heaters as heating elements.
- These are subject to certain security requirements. For example, there must be protection against fire, against leaks and against voltage flashovers on the heating element. In particular, voltage flashovers may not be protected by the existing building or house fuses according to a valid standard.
- thermal circuit breakers, pressure switches, which detect the presence of a fluid, or fuses are used, which come in the case of a drying path and the resulting constant heating of the heating element to melt and separate the heating circuit.
- the heater is configured to control the heating temperature of the heating element using a pulse-pause principle.
- the preselection of the heating temperature is determined by a scaling means, which is designed as a voltage divider, in which a resistance is variable by a user.
- the object of the present invention is to provide a heating device for fluids, which has a simple and inexpensive protection device for protecting a heating element of the heater from overheating. It is a further object of the present invention to provide a household appliance in which the monitoring of a heater is realized on overheating in a simple, reliable and cost-effective manner.
- the protective device of the heating device for fluids, in particular for use in dishwashers is designed as an integrated circuit.
- the integrated circuit is preferably designed as a microcontroller, which indirectly enables a determination and monitoring of the temperature of the heating element in a mathematical manner in order to actuate the switching means when a predetermined temperature is exceeded.
- the departure of a discrete monitoring circuit and the replacement by an integrated circuit have the advantage of a particularly cost-effective and especially very flexible monitoring.
- the necessary algorithms and threshold values can be stored in a memory of the integrated circuit.
- the heater can thus be used identically in the widest variety of domestic appliances, in particular dishwashers, whereby in each case only parameters adapted to the domestic appliance need to be stored in the integrated circuit.
- the protection device is supplied with a voltage derived from the current flowing through the heating element.
- a current sensor means coupled to the heating element, at the output of which a current-proportional (voltage) signal flowing through the heating element can be tapped off, wherein the current sensor means is designed as a discrete component in the form of a shunt.
- the analog signal which can be tapped off at the shunt is converted by the integrated circuit into a digital signal for further processing by means of the integrated circuit, using an analog-to-digital converter. To evaluate this signal, a comparison value is necessary, e.g. can be read from a memory of the integrated circuit.
- the comparison value can also be supplied as a further input variable of the protective device in the form of a reference voltage.
- a scaling means at the output of which a signal proportional to the supply voltage of the heating element can be tapped off, wherein the scaling means is designed as a discrete component in the form of a voltage divider coupled to the supply voltage.
- the switching means for separating the heating circuit in the event of overheating is designed as a power semiconductor switch.
- the switching means is formed together with the protective device in an integrated circuit.
- the protection device is designed to detect a change in the resistance value of the heating element and to compare the resistance change with a reference value, preferably derived from the supply voltage, in order to be able to interrupt the heating circuit by driving the switching means when the reference value is exceeded.
- a reference value preferably derived from the supply voltage
- An inventive household appliance in particular dishwasher has devices for washing dishes and a heating device for heating liquid to be heated, in particular treatment liquid, for.
- B. rinsing liquor wherein the heater comprises a formed as an integrated circuit protection device for monitoring and deactivation of the heater, in the event of exceeding a predetermined temperature value of a heating element of the heater.
- the electronic monitoring of the heater ensures a reliable shutdown in case of overheating of the heater. In this case, operation of the dishwasher is made possible again as soon as the heating device has cooled down again.
- the electronic monitoring makes it possible to incorporate further influencing variables for switching off the heating device.
- a monitoring of the fill level of the rinsing liquor in the heating device can additionally be taken into account. If an electronic signal is emitted by a level gauge that the level has fallen below a predetermined value, the electronic protection device can already cause the heating device to be switched off before the critical temperature value of the heating device has been reached.
- the household appliance comprises a heating device as described above.
- the heating element of the heating device of the household appliance is preferably designed as a thick film heater whose resistance value is a function of its temperature. In this way, electronic monitoring can be made possible in a particularly simple manner, since the resistance value of the heating element can be calculated by the protective device.
- the principle underlying the invention of temperature monitoring of the heater is based on the DE 103 60 553.3 of the applicant, the content of which is incorporated in the present application.
- the computational determination of the resistance value can take place on the basis of the method described in this application. It is proposed not to resort to a direct measurement of the resistance of the heating element, but to calculate the resistance indirectly via a measurement of the current through the heating element and the voltage across the heating element. It is based on an approximation of the ratio formation (division) by a Taylor series development and terminated after the second term. The division is thus replaced by a subtraction, which is mathematically very easy to replicate.
- the switching means 2 is controllable via a switch control circuit 3.
- the switching means 2 may be in the form of a relay, which is turned on when the heating element 1 has not exceeded a predetermined temperature value, and is not turned on, as soon as a critical temperature value of the heating element 1 is exceeded.
- the switching means 2 could also be in the form of a power semiconductor switch, which is integrated together with the switch control circuit 3 in an integrated circuit.
- the switch control circuit 3 and a protective device 300 designed as an integrated circuit are supplied with a supply voltage by a power supply 200, which will not be further described below.
- the power supply 200 basically comprises a rectifier circuit that rectifies and transposes the AC signal present at the supply terminals VA1, VA2 to a corresponding voltage level to power the switch control circuit 3 and the protection device 300.
- the node formed between the heating element 1 and the current sensor means 4 forms an output 41 of the current sensor means 4. Between the output 41 and the supply terminal VA2 is applied to a voltage U s .
- the output 41 is coupled to a first input 63 of the protection device 300. This is represented by a microprocessor.
- a second input 62 of the protection device 300 is connected to a scaling means 5, which is formed by a voltage divider consisting of the resistors 51, 52. More specifically, the node 53 formed between the resistors 51, 52 is connected to the second input 62 of the protection device 300.
- An output 106 of the protection device 300 is coupled to a control input 31 of the switch control circuit 3. Upon application of a corresponding control signal at the output 106, the switch control circuit 3 is caused to set the switching means 2 from its closed state, in which the heating element 1 is energized, to an open state to interrupt the heating circuit.
- the heating device has the current sensor means 4 and the scaling means 5 as discrete components.
- the at this Components which can be tapped off from components are converted in the protective device 300 into digital signals by means of analog-to-digital converters connected to the inputs 63, 62, in order to enable computational further processing of the corresponding input variables. From these, as described in the applicant's DE 103 60 553.3, a resistance value corresponding to the temperature value of the heating element 1 is compared with a reference value, the reference value being set by the scaling means 5. From the determined resistance value of the heating element 1, it can be decided whether the temperature of the heating element 1 is in a temperature range outside the specification, which is indicative of a defect of the heating device or the device in which the heating device is installed. In this case, the protection device 300 outputs a signal at its output 106, which causes the switch control circuit 3 to open the switching means 2.
- the electronic monitoring of the temperature of the heating element 1 based on a determination of the resistance value and a mathematical evaluation of the signals obtained allows a particularly simple, inexpensive and reliable monitoring of the heater, which is particularly suitable for use in a dishwasher. This provides a particularly reliable heating device for fluids in which mechanical damage to the heating device is excluded in the case of a drying path.
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE200510029921 DE102005029921A1 (en) | 2005-06-22 | 2005-06-22 | Heating device for fluids and household appliance |
PCT/EP2006/060550 WO2006136464A1 (en) | 2005-06-22 | 2006-03-08 | Heating device for fluids and domestic appliance |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1896917A1 true EP1896917A1 (en) | 2008-03-12 |
Family
ID=36235447
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP06724972A Withdrawn EP1896917A1 (en) | 2005-06-22 | 2006-03-08 | Heating device for fluids and domestic appliance |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP1896917A1 (en) |
CN (2) | CN2884768Y (en) |
DE (1) | DE102005029921A1 (en) |
WO (1) | WO2006136464A1 (en) |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2007077170A2 (en) * | 2006-01-05 | 2007-07-12 | Arcelik Anonim Sirketi | A household appliance |
DE102007056917A1 (en) * | 2007-11-27 | 2009-06-04 | BSH Bosch und Siemens Hausgeräte GmbH | Method for tolerance compensation of electrical consumers |
EP2386680B1 (en) * | 2010-05-14 | 2014-06-04 | Electrolux Home Products Corporation N.V. | Heating circuit with monitoring arrangement for a household appliance |
EP2386675B1 (en) * | 2010-05-14 | 2014-07-16 | Electrolux Home Products Corporation N.V. | Heating circuit with monitoring arrangement for a household appliance |
ITMI20100862A1 (en) * | 2010-05-14 | 2011-11-15 | Electrolux Home Products Corporatio N N V | MONITORING OF FAILURES IN THE HEATING CIRCUIT OF A HOUSEHOLD APPLIANCE |
DE102011108991A1 (en) | 2011-08-01 | 2013-02-07 | Florian Schilling | Fluid-conveying pipe for supplying fluid e.g. diesel, to combustion engine, has sensor device to determine electric resistance of heating element, and controller to control power supply to control load current based on measurement signal |
DE102012023366B4 (en) * | 2012-11-29 | 2022-12-29 | Audi Ag | Method for operating a heater that can be used in a motor vehicle, a heater for a component of a motor vehicle and a motor vehicle |
CN108574265A (en) * | 2017-03-13 | 2018-09-25 | 鸿富锦精密工业(深圳)有限公司 | Temperature protection circuit |
CN108742414A (en) * | 2018-05-23 | 2018-11-06 | 佛山市顺德区美的洗涤电器制造有限公司 | Dish-washing machine heating protection method, device and computer readable storage medium |
KR20200087031A (en) * | 2019-01-10 | 2020-07-20 | 엘지전자 주식회사 | laundry machine having an induction heater |
DE102019103593A1 (en) * | 2019-02-13 | 2020-08-13 | Miele & Cie. Kg | Method and device for operating a household appliance having a treatment room with a heating element and household appliance |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AT300989B (en) * | 1969-03-11 | 1972-08-10 | Barvy A Laky Narodni Podnik | Acid-hardening paint that can be diluted with water |
IT1259221B (en) * | 1992-07-23 | 1996-03-11 | Zanussi Elettrodomestici | WASHING MACHINE WITH TEMPERATURE CONTROL DEVICE FOR ELECTRIC WATER HEATING BODIES |
AUPO043896A0 (en) * | 1996-06-13 | 1996-07-04 | Philips Electronics Australia Limited | Circuit arrangement for controlling a heating element |
DE19645095A1 (en) * | 1996-11-01 | 1998-05-07 | Ego Elektro Geraetebau Gmbh | Heating |
DE10220413A1 (en) * | 2002-05-08 | 2003-11-27 | Behr Gmbh & Co | Method and device for monitoring the temperature of an electric heating element |
DE10260163A1 (en) * | 2002-12-20 | 2004-07-08 | BSH Bosch und Siemens Hausgeräte GmbH | dishwasher |
DE10342924B4 (en) * | 2003-09-15 | 2006-07-06 | Geßler Electronic GmbH | Overheat protection circuit and method of operation thereof |
-
2005
- 2005-06-22 DE DE200510029921 patent/DE102005029921A1/en not_active Withdrawn
- 2005-11-08 CN CNU2005201290826U patent/CN2884768Y/en not_active Expired - Fee Related
-
2006
- 2006-03-08 WO PCT/EP2006/060550 patent/WO2006136464A1/en not_active Application Discontinuation
- 2006-03-08 CN CNA2006800222937A patent/CN101203819A/en active Pending
- 2006-03-08 EP EP06724972A patent/EP1896917A1/en not_active Withdrawn
Non-Patent Citations (1)
Title |
---|
See references of WO2006136464A1 * |
Also Published As
Publication number | Publication date |
---|---|
DE102005029921A1 (en) | 2007-01-04 |
CN101203819A (en) | 2008-06-18 |
WO2006136464A1 (en) | 2006-12-28 |
CN2884768Y (en) | 2007-03-28 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 20080122 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR |
|
RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: STICKEL, MARTIN Inventor name: WAGNER, FRANZ-JOSEF Inventor name: SCHWEIER, PETER |
|
RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: SCHWEIER, PETER Inventor name: WAGNER, FRANZ-JOSEF Inventor name: STICKEL, MARTIN |
|
17Q | First examination report despatched |
Effective date: 20080507 |
|
DAX | Request for extension of the european patent (deleted) | ||
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 20081118 |