US2927186A - Control device for a heating element - Google Patents

Control device for a heating element Download PDF

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Publication number
US2927186A
US2927186A US771858A US77185858A US2927186A US 2927186 A US2927186 A US 2927186A US 771858 A US771858 A US 771858A US 77185858 A US77185858 A US 77185858A US 2927186 A US2927186 A US 2927186A
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US
United States
Prior art keywords
pressure
control device
switch blade
heating
switch
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
US771858A
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English (en)
Inventor
Brandl Wilhelm
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Individual
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Individual
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Publication date
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Publication of US2927186A publication Critical patent/US2927186A/en
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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B1/00—Details of electric heating devices
    • H05B1/02—Automatic switching arrangements specially adapted to apparatus ; Control of heating devices
    • H05B1/0202—Switches
    • H05B1/0208—Switches actuated by the expansion or evaporation of a gas or liquid
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/02—Details
    • H01H37/32—Thermally-sensitive members
    • H01H37/36—Thermally-sensitive members actuated due to expansion or contraction of a fluid with or without vaporisation

Definitions

  • the present invention relates to a control device for a heating element such as is known for example from the US. Patent No. 2,850,611.
  • This control device is provided with a pressure-sensitive switching element which through the agency of an adjustable switch blade, controls a switch for supplying current to the heating element, with which the said switching element is connected by way of a pipe.
  • the control device is characterized in that there is superimposed on the switch blade a compensating spring whose action, in accordance with the setting of the switch blade, is such that if the switch fails the switch blade closes the contacts of a short-circuiting cutout safety arrangement after a pressure increase in the heating element independent of the adjusted temperature.
  • the heating element to which the control device is connected is illustrated diagrammatically and on a relatively small scale.
  • the control device 1 comprises a carrier plate 2 on which a pressure-sensitive element is arranged.
  • this pressure-sensitive element consists of a bellows 3, whose base is fixedly secured to a strap 4 mounted on the carrier plate 2.
  • the movable end of the bellows 3 is connected to an elastic switch blade 7 by means of a rod 5 and nuts 6.
  • This switch blade 7 extends through a bearing member 8 which is fixed on the carrier plate 2.
  • Extending perpendicular to this bearing member 8 is a second bearing member 9 in which an adjusting screw 10 is mounted.
  • This screw 10 comprises a knob 11, having a pointed portion 12 which is movable opposite a scale 13.
  • a further screw 14 by means of which the initial stress of the switch blade 7 can be regulated. Adjusting nuts 15 serve to maintain the desired amount of initial stress.
  • a compensating spring 16 which extends from the lower end of the switch blade 7 to the point of the screw 10 parallel to the switch blade 7, and then extends at an angle to the latter by way of a slot in the bent-over end 17 of the bearing member 9.
  • the end 18 of the compensating spring 16 is situated over the head 19 of a bolt 20 which is fixed on the end of the switch blade 7.
  • the free end of this bolt 20 operates the press-button 21 of a microswitch 22, which is fixed by means of screws 23 to the carrier plate 2.
  • This end also carries a contact 25 which co-operates with a fixed, adjustable contact 24 arranged on the carrier plate 2.
  • the bellows 3 is connected through a pipe 26 (or a flexible tube) to the evacuated vessel 27 of a heating element 28, which serves for heating a device 29 (e.g. a cooking pot or a washing machine tube).
  • the vessel 27 contains a heating medium which is heated by means of an electrical resistance 30.
  • This heating resistance 30 is connected by way of a conductor 31 to the switch 2,927,186 7 Patented Mar. 1960 22 and by way of a conductor 32 to one phase of the current source 33, the other phase being connected by way of a conductor 34 to the other contact of the switch 22.
  • the contacts 24, 25 also serve as short-circuiting cutout means to guard against failure of the switch 22 to operate, since they are connected through the conductors 35 and 36 to the conductors 31 and 32 respectively.
  • control device which has been described hereinbefore operates in the following manner:
  • the desired heating temperature is adjusted by means of the knob 11.
  • the bolt 20 is thereby pressed against the press-button 21 and the circuit of the heating resistance 30 is closed.
  • the movement of the screw 10 lifts away the end 18 of the compensating spring 16, so
  • the end 18 of the compensating spring 16 is spaced more or less far from the head 19 of the bolt 20. If the pressure in the bellows 3 rises above the adjusted value, it must act in opposition not only to the effect of the elastic switch blade 7 but also to the action of the compensating spring 16. Thus the pressure increase above the adjusted value which will bring about short-circuiting can be kept constant.
  • control device which is illustrated in the drawing is characterized in that a compensating spring is so mounted, that, irrespective of what pressure is adjusted, after switching-0E a constant excess pressure is always necessary in order to lift away the elastic switch blade so far that it operates a short-circuiting cutout means or a circuit breaker switch, and also prevents the pressure-sensitive element from expanding more than is necessary when the control device is relieved of load.
  • the compensating spring acts to prevent the contacts 24 and 25 from closing the short-circuiting circuit for the heating resistance 30 until a definite pressure, in addition to that required to release the microswitch, is established in the bellows 3.
  • the microswitch fails to open, the resistance 30 continues to build up pressure in the bellows, the switch blade moves the bolt into contact with the compensating spring 16 and against its pressure, and the contacts 24 and 25 are brought together closing the short-circuiting circuit.
  • the heating resistance 30 is thus de-energized, and a dangerous condition is avoided.
  • a control device for an'electrical heater containing a fluid expansible with heat comprising a bellows connected to the fluid in the heater responsive to the pressure-thereof, an adjustable switch blade having one end restrained and connected to said bellows for movement thereby, a boltconnected to the free endof said switch blade for axial movement to close the heating circuit through the electrical heater, a short-circuiting circuit for the electrical heater including two normally open contacts, one of such contacts being carried by said belt for closing said contacts following movement away from heating circuit closing position, and a compensating spring having an end adjacent the end of said bolt opposite to that which acts to close :the heating circuit for retar inglos ng f said .shorecircuiting uit conta ts until a pr d term n d pressure exists in said b l above that for which said switch ,blade is adjusted.
  • a control device for an electrical heater comprising a heating vessel, an electrical resistance ,for heating said vessel, a microswitch for opening and closing the circuit through said electrical resistance, a bellows connected to at said vessel for expansion and contraction responsive to the pressure therein, an adjustableswitch blade operable by said bellows, a bolt carried by said switch blade for movement with said switch blade to close said microswitch, and in opposite direction to permit said microswitch to open an electrical circuit short-circuiting said electrical resistance, andnormally open contacts for said short-circuiting circuit, one of said contacts being carried on said bolt “for closing said contacts when said bolt is moved to permit said microswitch to open, in combination with a compensating spring superimposed on said switch blade and spaced from the head of said bolt in the adjusted position of said switch blade to apply pressure to said bolt head when pressure in said bellows

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  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Control Of Resistance Heating (AREA)
  • Control Of Temperature (AREA)
  • Thermally Actuated Switches (AREA)
US771858A 1957-11-04 1958-11-04 Control device for a heating element Expired - Lifetime US2927186A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH845954X 1957-11-04

Publications (1)

Publication Number Publication Date
US2927186A true US2927186A (en) 1960-03-01

Family

ID=4541823

Family Applications (1)

Application Number Title Priority Date Filing Date
US771858A Expired - Lifetime US2927186A (en) 1957-11-04 1958-11-04 Control device for a heating element

Country Status (5)

Country Link
US (1) US2927186A (es)
BE (1) BE572639A (es)
DE (1) DE1180469B (es)
GB (1) GB845954A (es)
NL (1) NL99738C (es)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3073940A (en) * 1960-02-05 1963-01-15 Brandl Wilhelm Safety device for heating appliances
US6363218B1 (en) * 1999-01-15 2002-03-26 Ail Research, Inc. Liquid heater load control

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2289882A (en) * 1941-06-12 1942-07-14 John W Myers Temperature control system
US2611850A (en) * 1948-04-30 1952-09-23 Diamond H Switches Ltd Thermostatic control system for ovens
US2678379A (en) * 1953-05-14 1954-05-11 Gen Motors Corp Domestic appliance

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE266836C (es) *
DE283077C (es) *
DE613688C (de) * 1931-07-12 1935-05-23 Siemens Schuckertwerke Akt Ges Anordnung an elektrischen Anlagen mit einer geerdeten oder genullten Schutzleitung
CH315829A (de) * 1950-12-13 1956-09-15 Voigt & Haeffner Ag Elektrisch beheiztes Gerät mit mehreren Heizleitern
DE1006543B (de) * 1953-04-17 1957-04-18 Guenther Klewer UEberwachungsvorrichtung fuer elektrische Heizeinrichtungen

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2289882A (en) * 1941-06-12 1942-07-14 John W Myers Temperature control system
US2611850A (en) * 1948-04-30 1952-09-23 Diamond H Switches Ltd Thermostatic control system for ovens
US2678379A (en) * 1953-05-14 1954-05-11 Gen Motors Corp Domestic appliance

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3073940A (en) * 1960-02-05 1963-01-15 Brandl Wilhelm Safety device for heating appliances
US6363218B1 (en) * 1999-01-15 2002-03-26 Ail Research, Inc. Liquid heater load control

Also Published As

Publication number Publication date
DE1180469B (de) 1964-10-29
GB845954A (en) 1960-08-24
NL99738C (es)
BE572639A (es)

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