EP0740008B1 - Safety switching apparatus against dry operation of electrical heating resistances, particularly for washing machines and dishwashers - Google Patents

Safety switching apparatus against dry operation of electrical heating resistances, particularly for washing machines and dishwashers Download PDF

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Publication number
EP0740008B1
EP0740008B1 EP96105206A EP96105206A EP0740008B1 EP 0740008 B1 EP0740008 B1 EP 0740008B1 EP 96105206 A EP96105206 A EP 96105206A EP 96105206 A EP96105206 A EP 96105206A EP 0740008 B1 EP0740008 B1 EP 0740008B1
Authority
EP
European Patent Office
Prior art keywords
heating
control
switch
washing machine
level
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.)
Expired - Lifetime
Application number
EP96105206A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0740008A2 (en
EP0740008A3 (en
Inventor
Gismar c/o Whirlpool Europe s.r.l Eck
Margret c/o Whirlpool Europe s.r.l Thumm-Jorge
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 Europe BV
Original Assignee
Whirlpool Europe BV
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
Priority claimed from DE19515902A external-priority patent/DE19515902C1/de
Application filed by Whirlpool Europe BV filed Critical Whirlpool Europe BV
Publication of EP0740008A2 publication Critical patent/EP0740008A2/en
Publication of EP0740008A3 publication Critical patent/EP0740008A3/en
Application granted granted Critical
Publication of EP0740008B1 publication Critical patent/EP0740008B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • A47L15/4285—Water-heater arrangements
    • 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
    • D06F37/00—Details specific to washing machines covered by groups D06F21/00 - D06F25/00
    • D06F37/42—Safety arrangements, e.g. for stopping rotation of the receptacle upon opening of the casing door
    • 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 
    • D06F39/04—Heating arrangements
    • 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
    • D06F2103/00—Parameters monitored or detected for the control of domestic laundry washing machines, washer-dryers or laundry dryers
    • D06F2103/18—Washing liquid level
    • 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
    • D06F2105/00—Systems or parameters controlled or affected by the control systems of washing machines, washer-dryers or laundry dryers
    • D06F2105/28—Electric heating
    • 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
    • D06F34/00—Details of control systems for washing machines, washer-dryers or laundry dryers
    • D06F34/08—Control circuits or arrangements thereof

Definitions

  • the invention relates to a washing machine or dishwasher, with a control motor of a program switching mechanism or of a corresponding software/hardware combination with partly and fully electrical program controls and level switches for monitoring and regulating the water level in the appliance, having a safety switching apparatus against dry operation of electrical resistances.
  • Such a safety switch apparatus is known from DE-AS 26 47 616.
  • the two level switches monitor a lower and an upper safety level and are used to increase the number of possible water levels, so that the washing procedure may be carried out with a reduced consumption of energy.
  • no additional security against dry operation of the heating resistance is achieved with the two level switches, in comparison to otherwise conventional safety switching arrangements.
  • the electrical heating circuit is normally switched on by a level switch.
  • the control motor for the program switch is preceded by a control contact which closes one or two steps before the control contact which switches on the heating circuit.
  • This circuit ensures that even if the water supply fails and there is phase contact from the heating side when the machine is connected to a grid with "earthing" protection, dry operation is excluded as the program switch cannot pass into the heating stage.
  • a safety switching apparatus which provides a temperature regulator and a temperature restricting means.
  • security against dry operation of the electrical heating resistances is achieved in that at least two contacts of the temperature regulator and of the temperature restricting means, switching the heating directly, are incorporated in series with the heating resistances in such a way that one is incorporated respectively before and after the heating resistances.
  • Also incorporated in the series arrangement is the contact of a level switch, whose fault function however is not monitored.
  • the reaction time of the temperature restricting means or of the thermostats limits its effectiveness. Particularly when plastics are used in the vicinity of the heating resistances, severe damage or fire can occur before the safety members respond. Their effectiveness cannot be guaranteed over the entire depth of the appliance in the case of any containers standing at an oblique angle.
  • tubular heating members can burn out when they become overheated, for example when operated in a dry state. This type of fault is not reliably recognised by temperature restricting means or thermostats.
  • this procedure may be produced by a corresponding combination of software and hardware.
  • Each of the two level switches in the outset position, switches a response circuit for the operating motor, said circuit being maintained through control contacts of the control motor only in the heating and washing stage and/or the subsequent rinsing procedures; then after the water is pumped out after the heating and washing stage, the final or intermediate spin can be stopped, of one of the two level switches does not revert to its outset position because of occurrence of a fault.
  • the user receives washing which has not been spin-dried. Because of this failure he is motivated to call the repair service in order to have the damage rectified before a safety-threatening fault, failure of the second level switch, occurs. Therefore by means of using two level switches, it is not only the redundancy which is increased in a known way. In the configuration described above, the two switches monitor one another.
  • a relay is used as a switch element.
  • electronic controls the procedure described above may be realised by a corresponding software/hardware combination.
  • the circuit diagram in Fig. 1 shows the safety switching apparatus in the start and water intake stage, in which only the control contact tm5 of the control motor StM (program switch) is closed.
  • a circuit for the water feed valve WV is closed by the closed-contact side 1-2 of the relay R and the control contact tm5.
  • the contacts nv1 and nv2 of the level switches NV1 and NV2 remain in their closed positions 1-2.
  • the position of the control contacts tm3 and tm4 is irrelevant.
  • the control motor StM is not initiated in the starting and water intake stage.
  • the contacts nv1 and nv2 switch on the switch element R, which is in the form of a relay, but which may also be in the form of an electronically-operating switching apparatus.
  • the switch element R By means of the contact r (1-3) of the switch element R, the water intake valve WV is switched off, and the control motor StM triggered and thus switched forward.
  • the control contacts tm1 and tm2 are closed and the heating resistance H (with any preceding thermostat Th) is switched in parallel with the switch element R. The heating and washing stage is thus initiated.
  • the control contacts tm3 and tm4 are effective in the circuit of the operating motor AM. The wash procedure can begin.
  • control contacts tm1, tm2 and tm5 are opened, while the control contact tm6 is closed and takes over triggering of the control motor StM, even when the switch element R reverts to the outset position.
  • the water is pumped out, and the level switches NV1 and NV2 reach their switch-back level.
  • the contacts nv1 and nv2 revert to their outset position 1-2.
  • the rinsing and spinning stages proceed in a known way, as the contacts nv1 and nv2 of level switches NV1 and NV2 close the circuit for the operating motor AM, independently of the position of the control contacts tm3 and tm4 which, in effect, as Fig. 2 shows, are not closed during the spin procedure. Therefore the spin procedure only takes place if both level switches NV1 and NV2 have reached their outset position.
  • the control contacts tm3 and tm4 may also be open during each intermediate spin procedure, so that intermediate spinning also is stopped.
  • the safety switching apparatus When a fault occurs, the user receives washing which has not been spin-dried, and is obliged to call the repair service to rectify the damage. In this way considerably greater security is achieved against dry operation of the heating resistance H.
  • the safety switching apparatus is symmetrical in structure, protection is always provided even from an earth-leakage fault by one of the two level switches and a control contact.
  • the control contacts tm3, tm4 and tm6 easily-recognisable yet not safety-threatening breakdowns are deliberately produced for the user, and with as a rule the desired effect - repair service, damage repair - as a consequence.

Landscapes

  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Washing And Drying Of Tableware (AREA)
  • Control Of Washing Machine And Dryer (AREA)
EP96105206A 1995-04-29 1996-04-01 Safety switching apparatus against dry operation of electrical heating resistances, particularly for washing machines and dishwashers Expired - Lifetime EP0740008B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19515902 1995-04-29
DE19515902A DE19515902C1 (de) 1995-03-31 1995-04-29 Sicherheitsschalteinrichtung gegen das Trockengehen elektrischer Heizwiderstände für Wasch- und Geschirrspülmaschinen

Publications (3)

Publication Number Publication Date
EP0740008A2 EP0740008A2 (en) 1996-10-30
EP0740008A3 EP0740008A3 (en) 1998-01-28
EP0740008B1 true EP0740008B1 (en) 2002-08-28

Family

ID=7760763

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96105206A Expired - Lifetime EP0740008B1 (en) 1995-04-29 1996-04-01 Safety switching apparatus against dry operation of electrical heating resistances, particularly for washing machines and dishwashers

Country Status (2)

Country Link
EP (1) EP0740008B1 (es)
ES (1) ES2181820T3 (es)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ITTO20120057A1 (it) * 2012-01-24 2013-07-25 Indesit Co Spa Macchina di lavaggio

Family Cites Families (4)

* 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
GB1282124A (en) * 1969-12-05 1972-07-19 Kenwood Mfg Woking Ltd Domestic appliances
DE3228744A1 (de) * 1982-07-31 1984-02-02 Miele & Cie GmbH & Co, 4830 Gütersloh Schaltungsanordnung fuer die programmsteuerung einer wasch- oder geschirrspuelmaschine
IT1239195B (it) * 1990-04-18 1993-09-28 Zanussi Elettrodomestici Dispositivo di controllo per macchine combinate per il lavassio e l'asciugatura della biancheria

Also Published As

Publication number Publication date
EP0740008A2 (en) 1996-10-30
ES2181820T3 (es) 2003-03-01
EP0740008A3 (en) 1998-01-28

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