US3225267A - Timed electric heating apparatus - Google Patents

Timed electric heating apparatus Download PDF

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Publication number
US3225267A
US3225267A US107994A US10799461A US3225267A US 3225267 A US3225267 A US 3225267A US 107994 A US107994 A US 107994A US 10799461 A US10799461 A US 10799461A US 3225267 A US3225267 A US 3225267A
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US
United States
Prior art keywords
relay
capacitor
voltage
current
filled tube
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
US107994A
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English (en)
Inventor
Goran A R Ojelid
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.)
Husqvarna Vapenfabriks AB
Original Assignee
Husqvarna Vapenfabriks AB
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.)
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Publication date
Application filed by Husqvarna Vapenfabriks AB filed Critical Husqvarna Vapenfabriks AB
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Publication of US3225267A publication Critical patent/US3225267A/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
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/66—Circuits
    • 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
    • G05D23/1951—Control of temperature characterised by the use of electric means with control of the working time of a temperature controlling device
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/28—Modifications for introducing a time delay before switching
    • H03K17/288—Modifications for introducing a time delay before switching in tube switches

Definitions

  • a capacitor is adapted to be charged, through an adjust-able resistance, with direct current from a current source, the voltage of which is in direct proportion to the operation voltage of the oven, and to cause a switch, at a predetermined voltage, to switch off the oven, preferably by ionizing inert gas in a bulb and thereby establishing an operating circuit for at least one relay.
  • the oven 1 is represented in the shape of a micro-wave oven and a magnetron 2 coupled thereto.
  • the oven requires, on one hand, low voltage current for the heating of a cathode 4, and, on the other hand, a high voltage between the cathode 4 and the anode of the magnetron, which is, inthis case, connected to the oven.
  • the high volt-age is supplied by a transformer 5, the primary current supply of which is controlled by a relay 6.
  • relay 6 The operation of relay 6 is controlled by two further relays 7 and 8 which, in their turn, are controlled by a tube 9 filled with an inert gas, a capacitor 10 and a bank of graphite resistors 11 in response to manual setting of push-button switches 15, 30, 45, 60, 120 and 240 respectively, all having break contacts.
  • Relay 6 receives its operating current from the supply system terminal 30 of the oven through a micro-switch 14 positively connected to the door 13 of the oven, a break contact of relay 8, a make contact of relay 7, junction points 33, 34, 35, 36 of the network, a fuse 12, a switch 32 which is the OFF switch of the oven and interrupts the current when pressed, and back to the terminal 31 of the mains.
  • Relays 7 and 8 have their operating coils connected in series, and they receive operating current from the terminal 30 of the mains through a series resistor 24, a rectifier 17 with a filter capacitor 18, the operating coils of relays 7 and 8, a switch 37 for the high frequency, junction 38 of the network, the main discharge path of tube 9, junctions 41, 33, 34, 35, 36 of the network, fuse 12, switch 32 and back to the terminal 31 of the mains.
  • Relays 7 and 8 are thus energized with direct current, obtained by rectification and filtering of current from the main supply system.
  • the inert gas in the tube 9 is electrically isolating in its normal condition but becomes ionized and thereby conducting at a certain electrical field intensity.
  • the capacitor 10 is coupled over the ignition gap and adapted, when relay 7 is energized, to be charged with current, which is applied from the filter ca- 3,225,267 Patented Dec. 21, 1965 pacitor 18 of rectifier 17 through the coil of a relay 7, a resistor 20, junction 40, and the switches 15-240, or, if some of the switches should have been manipulated, through corresponding graphite resistor(s) 11 and junctions 41, 33, 34.
  • a rheostat 22 is interconnected in such a way, that it forms, together with the resistor 20, an adjustable voltage divider.
  • the current flowing through resistor 20 is not sufficient to operate relay 7, but the current through resistor 27 slowly increases the potential of the capacitor 10.
  • the potential of capacitor 10 becomes so high, that the gas in tube 9 will be ionized.
  • the tube then becomes conducting and establishes the circuit through the coils of relays 7 and 8 from point 44, through the operating coils of relays 7 and 8 respectively, switch 37, junction 38, the main discharge path of tube 9 to points 41, 33 and 34, which causes actuation of these two relays.
  • lamp 25 becomes lighted through the make contact of relay 8 to indicate that the oven is ready for use.
  • Relay 6 remains, however, de-energized, since its operating circuit from terminal 30 through the coil of relay 6, switch 14 (transferred), the break contact of relay 8, the make contact of relay 7, junctions 33, 34, 35, 36, fuse 12, switch 32, to the terminal 31 of the mains is interrupted at relay 8.
  • a suitable working period is selected simply by manipulating one or more of the switches 15, 30, 45, 60, 120, 180, 240. Such manipulation will mechanically close the switch 43, which means that the junction 40 between the resistors 20, 22 of the voltage divider becomes connected to the bank of resistors 11. Therefore, current flows from said junction through switch 43 and the switches not manipulated and through the resistor 11 corresponding to the manipulated switch to the capacitor 10 with the return path extending through junctions 41, 33 and 34. As long as tube 9 is conducting it is not possible for the potential of the capacitor to rise. The working period is now commenced by manipulating the switch 37 which is adapted the operation of the oven.
  • the rheostat In the manufacture of the oven the rheostat will be set in such a Way, that the time for increasing the potential of the capacitor to the ionization voltage of the tube exactly corresponds to the marking of the manipulated switch, if the voltage of the electrical supply system is nominal.
  • the operating circuit of relay 8 becomes established through the ionization of tube 9 with the consequence that relay 6 again becomes deprived of its operating current and interrupts If the voltage of the main electrical supply system should deviate from its nominal value, this will influence the time for reaching the ionization voltage in two ways, which have mutually opposite signs of alternation.
  • Too low a voltage of the main supply system thus tends on the one hand to increase the time of the capacitor for reaching a certain potenital and tends, on the other hand, to increase the voltage necessary for ionization the latter circumstance being due to the reduced voltage over the main discharge path of the tube.
  • Suitable values of the components of the disclosed device are:
  • the relay 6 has the shape of a step relay, which successively inserts different functions of the oven, e.g., different power stages, and also successively interconnects diiferent resistors 11 in the charging circuit of the capacitor 10 for controlling a whole working cycle with varying length of the individual operation parts.
  • an electric heating device having an energizing source, first means connected with the energizing source for providing a direct current voltage which is directly proportioned to a Voltage of the energizing source; a capacitor; an adjustable resistor interconnected between said capacitor and said first means and through which said capacitor is charged from said first means; a gas filled tube; an ignition electrode in said gas filled tube; second means connecting said capacitor to said ignition electrode for ionizing the gas in said gas filled tube when thevoltage of said capacitor has reached the break down voltage of said gas filled tube; a first relay having an energizing winding which is connected in series with the main discharge path of said gas filled tube and said first means; said relay having a movable contact connected with said heating device for breaking the current to said electric heating device when said relay contact becomes transferred through the ionization of the gas in said gas filled tube and the appurtenant current through the energizing winding of said relay; and a second relay having a holding circuit for maintaining said second
  • heating apparatus in which said heating apparatus is a dielectric one having a high frequency generator fed with direct current.
  • a heating apparatus in which said high frequency generator is of the magnetron type.
  • the adjustable resistor is comprised of a plurality of resistors connected in series and individually held short-circuited by the break contact of one of a plurality of switches, which are manipulated by means of individual push-buttons, marked with the charging time pertaining to the respective resistors at nominal operating voltage of the heating apparatus.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Control Of High-Frequency Heating Circuits (AREA)
  • Control Of Resistance Heating (AREA)
US107994A 1960-05-09 1961-05-05 Timed electric heating apparatus Expired - Lifetime US3225267A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE456460 1960-05-09

Publications (1)

Publication Number Publication Date
US3225267A true US3225267A (en) 1965-12-21

Family

ID=20264457

Family Applications (1)

Application Number Title Priority Date Filing Date
US107994A Expired - Lifetime US3225267A (en) 1960-05-09 1961-05-05 Timed electric heating apparatus

Country Status (5)

Country Link
US (1) US3225267A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
CH (1) CH411088A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
DE (1) DE1136431B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
GB (1) GB932314A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
NL (1) NL264486A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3480753A (en) * 1968-02-16 1969-11-25 Robert G Wilson Electronic oven

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1985051A (en) * 1931-04-17 1934-12-18 Westinghouse Electric & Mfg Co Control system
US2504955A (en) * 1945-06-01 1950-04-25 Girdler Corp High-frequency treating system for dielectric materials
US2541560A (en) * 1947-02-20 1951-02-13 Spencer A Tucker Electronically timed relay
US2551224A (en) * 1947-02-24 1951-05-01 Edi Holding Inc Cold cathode triode electronic timer
US2763758A (en) * 1953-04-21 1956-09-18 Kohler Fred Arc suppresser for dielectric heating equipment
US2839649A (en) * 1956-05-17 1958-06-17 Gen Electric Control circuits for electronic ranges
US2921171A (en) * 1956-06-04 1960-01-12 Gen Motors Corp Domestic appliance
GB877553A (en) * 1960-04-14 1961-09-13 Maytag Co Improvements in or relating to control systems for clothes drying apparatus
US3028472A (en) * 1959-01-14 1962-04-03 Gen Electric Timer systems for cooking apparatus, or the like

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1985051A (en) * 1931-04-17 1934-12-18 Westinghouse Electric & Mfg Co Control system
US2504955A (en) * 1945-06-01 1950-04-25 Girdler Corp High-frequency treating system for dielectric materials
US2541560A (en) * 1947-02-20 1951-02-13 Spencer A Tucker Electronically timed relay
US2551224A (en) * 1947-02-24 1951-05-01 Edi Holding Inc Cold cathode triode electronic timer
US2763758A (en) * 1953-04-21 1956-09-18 Kohler Fred Arc suppresser for dielectric heating equipment
US2839649A (en) * 1956-05-17 1958-06-17 Gen Electric Control circuits for electronic ranges
US2921171A (en) * 1956-06-04 1960-01-12 Gen Motors Corp Domestic appliance
US3028472A (en) * 1959-01-14 1962-04-03 Gen Electric Timer systems for cooking apparatus, or the like
GB877553A (en) * 1960-04-14 1961-09-13 Maytag Co Improvements in or relating to control systems for clothes drying apparatus

Also Published As

Publication number Publication date
CH411088A (de) 1966-04-15
DE1136431B (de) 1962-09-13
GB932314A (en) 1963-07-24
NL264486A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

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