EP1211344A1 - Waschmaschine mit einem Sensor zur kontinuierlichen Wasserstandmessung - Google Patents

Waschmaschine mit einem Sensor zur kontinuierlichen Wasserstandmessung Download PDF

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Publication number
EP1211344A1
EP1211344A1 EP00126605A EP00126605A EP1211344A1 EP 1211344 A1 EP1211344 A1 EP 1211344A1 EP 00126605 A EP00126605 A EP 00126605A EP 00126605 A EP00126605 A EP 00126605A EP 1211344 A1 EP1211344 A1 EP 1211344A1
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EP
European Patent Office
Prior art keywords
sensor
cwl
washing machine
microprocessor
comparator
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
EP00126605A
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English (en)
French (fr)
Other versions
EP1211344B1 (de
Inventor
Raffaele c/o Whirlpool Europe s.r.l. Paganini
Daniele c/o Whirlpool Europe S.r.l. Turetta
Nikolaus c/o Whirlpool Europe s.r.l. Wingert
Giorgio c/o Whirlpool Europe s.r.l. Zambon
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.)
Whirlpool Corp
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Whirlpool Corp
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 Whirlpool Corp filed Critical Whirlpool Corp
Priority to ES00126605T priority Critical patent/ES2225002T3/es
Priority to DE60012755T priority patent/DE60012755T2/de
Priority to EP00126605A priority patent/EP1211344B1/de
Publication of EP1211344A1 publication Critical patent/EP1211344A1/de
Application granted granted Critical
Publication of EP1211344B1 publication Critical patent/EP1211344B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
    • D06F39/00—Details of washing machines not specific to a single type of machines covered by groups D06F9/00 - D06F27/00 
    • D06F39/08—Liquid supply or discharge arrangements
    • D06F39/087—Water level measuring or regulating devices
    • A—HUMAN NECESSITIES
    • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
    • A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
    • A47L15/00—Washing or rinsing machines for crockery or tableware
    • A47L15/42—Details
    • A47L15/4244—Water-level measuring or regulating arrangements

Definitions

  • the present invention relates to a washing machine having a continuous water level (CWL) sensor connected to a control unit including a microprocessor.
  • CWL continuous water level
  • washing machine we mean all kinds of domestic appliances for washing laundry and for washing dishes as well.
  • the present invention can be used for horizontal, vertical and tilted axes machines.
  • Modern washing machines use a CWL sensor that is able to monitor continuously the water level inside the tub.
  • CWL is a sensor able to convert the pressure applied to the sensor (that is proportional to the water level in the tub) into an electrical signal.
  • the piezoresistive pressure transducers are for instance produced and sold by Motorola, Honeywell, Sensym, and they are designed for wide applications. This kind of sensor combines a sensitive implanted strain gauge with advanced bulk micromachine technique, thin film metalisation and bipolar processing in order to provide an accurate high level analog output (voltage) that it is proportional to the applied pressure.
  • Membrane displacement sensors are produced for instance by Huba.
  • This kind of CWL sensor is conceived as a low cost device for domestic appliances (particularly dishwashers). It is a displacement device where the deflection of a rubber membrane which results from the pressure acting on it, it is measured by a piezoresistive force sensor (Wheatstone bridge) obtained above an alumina substrate (by "Thick Film” technology) and on the same substrate the signal conditioning interface is also realized (by SMD technique).
  • the sensor is temperature compensated and amplified for providing an analog voltage output.
  • Inductive displacement sensor are produced for instance by ELBI / Bitron. This kind of sensor is conceived as a low cost device for domestic appliances. It is an inductive displacement device (sensitive devise) using an inductance coil circuit measuring the deflection of the rubber membrane (by a metal pivot connected with the rubber membrane), that results from the pressure acting upon it.
  • the above known sensors combine a sensitive device with a microprocessor integrated in the same package to provide an accurate high level analog output that it is proportional to the applied pressure.
  • the CWL sensor can be provided with the following different output types or it can be provided with multiple type of output: frequency, analog voltage output, PWM (pulse width modulation).
  • Washing machines are usually provided with electrical heater for heating tap water loaded in the machine in order to improve washing results.
  • Such heaters electrical resistances
  • Such heaters are designed for working in a fully submerged condition.
  • the demand of water saving has prompted appliance producers to design washing machines which use a reduced amount of water in each washing cycle.
  • This water reduction increases the risk of heater failure, i.e. a damage to the heater which can also cause risk of fire.
  • a heater failure occurs when the water in the tub or in the water circuit of the washing machine decreases under a certain level. When the water decreases under a certain level the heater becomes totally or partially dry and, as a consequence, inside the heater the temperature increases rapidly and the life of the heater is dramatically reduced.
  • the heater and the discharge pump are operated by the control unit of the machine to which dedicated pressure switches (of the type on/off and calibrated for certain fixed levels of water) are connected.
  • the control unit of washing machine using a continuos water level (CWL) sensor comprises usually a microprocessor or equivalent control system electronic device that is connected with the CWL sensor in order to allow the control unit to use the correct amount of water and consequently to achieve better performances and to optimize energy consumption.
  • CWL continuos water level
  • control unit In the case a CWL sensor is used, the control unit is not 100% safe since its microprocessor, in case of total or partial failure, cannot guarantee that the water level does not go under or upper the minimum and maximum value respectively.
  • the main object of the present invention is to provide a washing machine that can operate the heater independently from the microprocessor of the control unit in order to guarantee the heater reliability and safety.
  • Another object of the present invention is to provide a washing machine that can operate the discharge pump independently from the microprocessor in order to prevent water overflow.
  • a CWL sensor 10 is normally operated with pipeline connection that it is connected with air trap device (not shown) that it is connected with the tub (not shown).
  • the CWL sensor 10 can be assembled in order to be in direct contact with the media (water) without any pipeline.
  • CWL sensor can be also assembled directly on the printed circuit board (PCB) to reduce the harness cost, and it can be of a very simple type (basic pressure transducer) where an addition amplifier is required to be operated by the microprocessor and comparators.
  • the simple and low cost electronic circuit connected to the CWL sensor 10 and to the microprocessor 12 is able to operate directly the drivers of the heater and of the discharge pump even if a microprocessor fault occurs.
  • the control circuit comprises two comparators, respectively 14 and 16, with fixed thresholds acting independently and in parallel with the microprocessor 12.
  • the voltage output 10a of the CWL sensor 10 connected with the microprocessor 12 is connected in parallel with the two comparators 14 and 16.
  • the comparator outputs 14a and 16a are able to operate independently or in parallel with the microprocessor 12. Therefore, in case of failure of the microprocessor 12, the comparators 14 and 16 can drive the heater and/or the discharge pump independently from the microprocessor.
  • the first comparator 14 compares the output value 10a of the CWL sensor 10 with a fixed threshold 14b related to a minimum water level for a safe function of the heater.
  • the second comparator 16 compares the output value 10a of the CWL sensor 10 with a fixed threshold 16b related to a maximum water level above which the discharge pump is switched on.
  • the fixed thresholds are characteristics of each washing machine.
  • FIG 2 in which for the same or similar components the same reference numerals are used, shows the control circuit where the continuous water level sensor 10 has two outputs.
  • a square-wave output 10b is directly connected to the microprocessor 12 by pulsed width modulation PWM digital output signal (typically a timer event counter).
  • PWM digital output signal typically a timer event counter.
  • the second output 10a is, as in the embodiment of figure 1, an analog output (voltage) connected to the comparators 14 and 16.
  • Figure 3 shows a block diagram similar to figure 1 where the continuous control of the water level through the CWL sensor is performed with a single output.
  • a square-wave PWM output 10b of the sensor 10 is directly connected to the microprocessor 12 by PWM digital output and this signal is integrated by means of a resistor and a capacitor 22 which together perform the function of an integrator 24 in order to obtain analog signal 26 (voltage) to be connected with the comparators 14 and 16.
  • This solution is normally used with PWM signals or could be used with high frequency signals.
  • Figure 4 shows a block diagram similar to figure 3 where the continuous control of the water level through the CWL sensor is performed with a single output.
  • a square-wave frequency output 10b is directly connected to the microprocessor digital input and this signal is also connected with a device 28 usually called frequency to voltage converter (for example a component known with the name LM2907 manufactured by National Semiconductor).
  • This electronic component 28 is able to provide a voltage signal proportional to the input frequency.
  • This voltage output signal is connected with the comparators 14 and 16.
  • Figure 5 shows an example of the electronic circuit used to operate the driver for the heater and for the pump. It is based on dual voltage comparators using the LM393 component that it is an 8-pin integrated circuit and it is a very popular component with inside two open collector comparators that is sensible to the applied input voltage.
  • the first comparator (component LM 393 U1A in figure5) is used for checking the "Level 0".
  • a fixed voltage is established by a voltage divider connected to the inverter (-) inputs.
  • CWL continuos water level
  • the second comparator (LM 393 U1B in figure 5) is used for checking the condition of "Overflow".
  • the above behavior of the component LM 393 U1A is substantially identical for the LM 393 U1B component that is used to operate the discharge pump driver.
  • the only difference is the required different reference fixed voltage value, obtained by the voltage divider, connected to the inverter (-) inputs of the comparator. This reference voltage value has to be higher than the previous reference voltage value applied to the inverter input of the LM 393 U1A comparator.

Landscapes

  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Control Of Washing Machine And Dryer (AREA)
EP00126605A 2000-12-04 2000-12-04 Waschmaschine mit einem Sensor zur kontinuierlichen Wasserstandmessung Expired - Lifetime EP1211344B1 (de)

Priority Applications (3)

Application Number Priority Date Filing Date Title
ES00126605T ES2225002T3 (es) 2000-12-04 2000-12-04 Maquina lavadora con perceptor para deteccion continua del nivel del agua.
DE60012755T DE60012755T2 (de) 2000-12-04 2000-12-04 Waschmaschine mit einem Sensor zur kontinuierlichen Wasserstandmessung
EP00126605A EP1211344B1 (de) 2000-12-04 2000-12-04 Waschmaschine mit einem Sensor zur kontinuierlichen Wasserstandmessung

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP00126605A EP1211344B1 (de) 2000-12-04 2000-12-04 Waschmaschine mit einem Sensor zur kontinuierlichen Wasserstandmessung

Publications (2)

Publication Number Publication Date
EP1211344A1 true EP1211344A1 (de) 2002-06-05
EP1211344B1 EP1211344B1 (de) 2004-08-04

Family

ID=8170566

Family Applications (1)

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EP00126605A Expired - Lifetime EP1211344B1 (de) 2000-12-04 2000-12-04 Waschmaschine mit einem Sensor zur kontinuierlichen Wasserstandmessung

Country Status (3)

Country Link
EP (1) EP1211344B1 (de)
DE (1) DE60012755T2 (de)
ES (1) ES2225002T3 (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005060816A1 (de) * 2003-12-22 2005-07-07 BSH Bosch und Siemens Hausgeräte GmbH Geschirrspülmaschine mit einem system zur füllstandserkennung
WO2006033027A1 (en) * 2004-07-21 2006-03-30 Arcelik Anonim Sirketi Dishwasher with pulse width modulation control
DE102006052891A1 (de) * 2006-11-09 2008-05-15 BSH Bosch und Siemens Hausgeräte GmbH Wasserführendes Haushaltsgerät mit Flüssigkeitssensor
EP2382908A1 (de) * 2010-04-01 2011-11-02 Electrolux Home Products Corporation N.V. Verfahren zur Befüllung eines Spülbehälters einer Geschirrspülmaschine mit Wasser
WO2011113583A3 (en) * 2010-03-18 2011-11-10 Electrolux Home Products Corporation N.V. A method for filling a wash tub of a dishwasher with water
ITTO20110856A1 (it) * 2011-09-26 2013-03-27 Bitron Spa Apparecchio elettrodomestico di lavaggio provvisto di un dispositivo piezoelettrico.
US9839945B2 (en) 2014-05-02 2017-12-12 Electrolux Home Products, Inc. Methods, systems, and apparatuses for performing a quick cycle in a dishwasher
CN108642811A (zh) * 2018-04-10 2018-10-12 青岛海尔洗衣机有限公司 一种应用于洗衣机的水位检测装置和洗衣机的控制方法及洗衣机

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8619911B2 (en) 2009-12-15 2013-12-31 Stmicroelectronics International N.V. Quadrature signal decoding using a driver
US8654895B2 (en) 2009-12-15 2014-02-18 Stmicroelectronics International N.V. Frequency modulated signal decoding using a driver

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1585767A1 (de) * 1966-07-07 1971-07-29 Kieninger & Obergfell Elektronische Temperaturueberwachungseinrichtung
GB2070648A (en) * 1980-01-26 1981-09-09 Miele & Cie Washing machine
DE4029544A1 (de) * 1990-09-18 1992-03-19 Bosch Siemens Hausgeraete Sicherheitsvorrichtung fuer wasserfuehrende haushaltgeraete

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5305485A (en) * 1993-01-04 1994-04-26 Whirlpool Corporation Cloth detection system for an automatic washer

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1585767A1 (de) * 1966-07-07 1971-07-29 Kieninger & Obergfell Elektronische Temperaturueberwachungseinrichtung
GB2070648A (en) * 1980-01-26 1981-09-09 Miele & Cie Washing machine
DE4029544A1 (de) * 1990-09-18 1992-03-19 Bosch Siemens Hausgeraete Sicherheitsvorrichtung fuer wasserfuehrende haushaltgeraete

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005060816A1 (de) * 2003-12-22 2005-07-07 BSH Bosch und Siemens Hausgeräte GmbH Geschirrspülmaschine mit einem system zur füllstandserkennung
US8161987B2 (en) 2003-12-22 2012-04-24 Bsh Bosch Und Siemens Hausgeraete Gmbh Dishwasher with a system for recognition of filling level
WO2006033027A1 (en) * 2004-07-21 2006-03-30 Arcelik Anonim Sirketi Dishwasher with pulse width modulation control
DE102006052891A1 (de) * 2006-11-09 2008-05-15 BSH Bosch und Siemens Hausgeräte GmbH Wasserführendes Haushaltsgerät mit Flüssigkeitssensor
WO2011113583A3 (en) * 2010-03-18 2011-11-10 Electrolux Home Products Corporation N.V. A method for filling a wash tub of a dishwasher with water
US20130008477A1 (en) * 2010-03-18 2013-01-10 Electrolux Home Products Corporation N.V. Method for filling a wash tub of a dishwasher with water
US9936852B2 (en) 2010-03-18 2018-04-10 Electrolux Home Products Corporation N.V. Method for filling a wash tub of a dishwasher with water
EP2382908A1 (de) * 2010-04-01 2011-11-02 Electrolux Home Products Corporation N.V. Verfahren zur Befüllung eines Spülbehälters einer Geschirrspülmaschine mit Wasser
ITTO20110856A1 (it) * 2011-09-26 2013-03-27 Bitron Spa Apparecchio elettrodomestico di lavaggio provvisto di un dispositivo piezoelettrico.
US9839945B2 (en) 2014-05-02 2017-12-12 Electrolux Home Products, Inc. Methods, systems, and apparatuses for performing a quick cycle in a dishwasher
CN108642811A (zh) * 2018-04-10 2018-10-12 青岛海尔洗衣机有限公司 一种应用于洗衣机的水位检测装置和洗衣机的控制方法及洗衣机

Also Published As

Publication number Publication date
EP1211344B1 (de) 2004-08-04
DE60012755T2 (de) 2005-08-11
ES2225002T3 (es) 2005-03-16
DE60012755D1 (de) 2004-09-09

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