US3679908A - Safety device for sensing preventing radiation leakage from microwave-producing apparatus - Google Patents

Safety device for sensing preventing radiation leakage from microwave-producing apparatus Download PDF

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Publication number
US3679908A
US3679908A US98378A US3679908DA US3679908A US 3679908 A US3679908 A US 3679908A US 98378 A US98378 A US 98378A US 3679908D A US3679908D A US 3679908DA US 3679908 A US3679908 A US 3679908A
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United States
Prior art keywords
microwave
gas
producing apparatus
power supply
relay coil
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Expired - Lifetime
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US98378A
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English (en)
Inventor
Lamberto Mazza
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Industrie Zanussi SpA
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Industrie Zanussi SpA
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    • 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
    • H05B6/6414—Aspects relating to the door of the microwave heating apparatus
    • H05B6/6417—Door interlocks of the microwave heating apparatus and related circuits

Definitions

  • ABSTRACT A microwave-leakage preventing safety device, especially [30] Foreign Application Priority Da adapted for microwave cooking ovens and like appliances, which is characterized by a radiation sensitive gas lamp (or gas Jan. 17, 1970 Italy ..l95l0 A/70 diode) placed in the vicinity of the point at which radiation leakages are expected, for example the oven door, The gas [52] U.S.
  • VIVIV 3 Claims 3 Drawing Figures AA AAL W" H SAFETY DEVICE FOR SENSING PREVENTING RADIATION LEAKAGE FROM MICROWAVE- PRODUCING APPARATUS
  • This invention relates to a safety device against leakage of radiations which could take place in microwave-producing apparatus, more particularly ovens, especially at the doors which give access to the treatment environment.
  • microwave-producing apparatus should be equipped with appropriate protection adapted to prevent the emergence of radiations from the treatment environment.
  • Special difficulties have been encountered in producing devices adapted to prevent the emergence of radiations at the sealing regions between the door and the enclosing walls of the apparatus, since the resilient seals as usually provided rapidly deteriorate with the lapse of time and, finally, do not function adequately.
  • a doubtlessly improved approach in this direction has been to place, about the door outline, a waveguide assembly which is capable of sensing the radiation leakages through the above mentioned regions, and which is connected to a crystal detector intended to block the feeding to the microwave generator immediately when the radiation exceeds a predetermined safety level.
  • a device which is characterized in that it comprises at least a microwave-responsive gas tube which is located in the vicinity of possible radiation leakage regions, for example in the neighborhood of the oven door, said tube being electrically, inserted in the control circuit of a controlled diode, the latter being electrically inserted, in turn, in the feeding circuit of a relay whose energization controls the power supply to the electric circuit which feeds the microwave generator.
  • any radiation leakage which is sensed by the gas tube(s) causes a decrease of the resistance thereof, a fact which, in turn, causes the controlled diode to become conductive, this inturn causing the energization of the relay and finally the discontinuance of the power feed to the microwave generator.
  • FIG. 1 shows the oven in front elevational view.
  • HO. 2 shows the oven in side elevational view, partly in section, the door being left ajar.
  • FIG. 3 shows the wiring diagram of the radiation detecting safety device with which the oven is equipped.
  • the microwave oven shown in FIGS. 1 and 2 comprises a substantially prismatic body 1, in whose interior a cooking chamber 2 is confined, an emitting antenna 3 of a microwave generator 4 protruding thereinto.
  • the access to the cooking chamber 2 is through an opening 5 which is encircled by four curled resilient blades 6 and the chamber has a door 7.
  • the door in hinged at 8 to the front wall of the oven and can be operated between two end positions (wide open and fully closed) as defined by the engagement of either of two rollers 9 (a single roller has been shown) with either of two notches l0 and 11 formed in each of two levers 12 (a single lever being shown) hinged to the door sidewalls and held against the rollers 9 by respective springs 13 (only one has been shown).
  • the door 7 has a handle 14 and a transparent central area 15 consisting of a glass plate intended to act as a shield against the microwaves as emitted by the generator 4 while food is being cooked.
  • the seal which is required between the door 7 and the oven front wall is provided by four resilient blades 6 which are pressed by the door against the oven wall as the door is pushed towards the closed position, shown in dotted lines in FIG. 2.
  • the oven described herein has a device intended to block the operation of the microwave generator both if the door is opened and in the case of an exceedingly high radiation leakage caused by a poor seal provided by the resilient blades 6, or by breakage of the door shielding glass 15.
  • the device comprises a gas lamp 16, located above the door in a chamber 17 enclosed by a microwave-transparent wall 18, and is serially connected with a first relay coil 19 having a low energization current, with a resistor 20 and a potentiometer 21, in the control circuit of a controlled diode (SCR) 22 whose feeding circuitry comprises an AC source (not shown), a normally closed pushbutton switch 23, a full wave rectifier 24 and a second relay coil 25.
  • the two relay coils l9 and 25 control respective movable contacts 26 and 27, the first of which is normally open and the second normally closed, said contacts being serially connected in the electric feeding circuit of the microwave generator 4.
  • the pushbutton 27 should be depressed so as to deactivate the controlled diode 22, but not without removing the condition which caused the radiation leakage.
  • This pushbutton can also be coupled for operations with the starting pushbutton of the microwave generator (not shown). 7
  • the relay 19 has the function of cutting off the feed to the microwave generator, should the gas lamp break.
  • the single lamp 16 of H6. 1 could be replaced by a number of lamps connected in parallel and in alignment, in a circuit such as that of FIG. 3, after having adjusted the ohmic values.
  • the gas lamp 16 could be replaced by any other gas tube, such as a gas diode.
  • the device according to the invention could be employed, not only for an oven door, but also for any other component part of the oven in which radiation leakages are likely to occur, for example where there are welding seams, other shielding plate glass walls, and so forth.
  • the gas tubes should be provided at all the parts of the oven which could be regarded as being critical with respect to radiation leakage hazard.
  • the device according to the invention can be applied, in addition to microwave ovens, also to other kind of microwave-producing devices, such as driers of the kind disclosed and claimed in the Italian Patent specification No. 834,762, filed May 28, 1968 in the name of the same applicants.
  • a safety device for sensing and preventing radiation leakage from a microwave-producing apparatus comprising in combination: a first series branch including at least one gastube which is sensitive to microwave radiation and is located in a region of possible microwave radiation leakage, a first relay coil electrically connected in series with said gas-tube and arranged to operate a first set of contacts which are inserted in a power supply circuit of the micro-wave producing apparatus so as to break the power supply to the micro-wave producing apparatus upon de-energization of said first relay coil, and means sensitive to current passing through said first series branch; a second series branch connected in parallel with said first series branch and including a controlled diode and a second relay coil connected in series therewith, the
  • second relay coil connected to operate a second set of contacts which are inserted in said power supply circuit so as to break the power supply therein upon energization of said second relay coil; and a dc source supplying direct current to said first and second series branches, whereby, upon the gastube sensing microwave leakage, the power supply to the microwave-producing apparatus is interupted.
  • a device characterized in that said gas tube is a gas lamp.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Electric Ovens (AREA)
  • Constitution Of High-Frequency Heating (AREA)
  • Control Of High-Frequency Heating Circuits (AREA)
  • Drying Of Solid Materials (AREA)
  • Rotary Switch, Piano Key Switch, And Lever Switch (AREA)
US98378A 1970-01-17 1970-12-15 Safety device for sensing preventing radiation leakage from microwave-producing apparatus Expired - Lifetime US3679908A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT1951070 1970-01-17

Publications (1)

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US3679908A true US3679908A (en) 1972-07-25

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US98378A Expired - Lifetime US3679908A (en) 1970-01-17 1970-12-15 Safety device for sensing preventing radiation leakage from microwave-producing apparatus

Country Status (5)

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US (1) US3679908A (enrdf_load_stackoverflow)
JP (1) JPS541939B1 (enrdf_load_stackoverflow)
DE (1) DE2029559C3 (enrdf_load_stackoverflow)
FR (1) FR2080555B3 (enrdf_load_stackoverflow)
GB (1) GB1298163A (enrdf_load_stackoverflow)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3746824A (en) * 1972-08-07 1973-07-17 Gen Electric Microwave oven leakage radiation detecting device
US3900713A (en) * 1973-03-26 1975-08-19 Micro Devices Corp Thermal limiter construction and electrical switch and system utilizing the same
US4253092A (en) * 1979-04-19 1981-02-24 Connah John F Jun Microwave leakage detector
US4529855A (en) * 1982-04-12 1985-07-16 Henry Fleck Microwave radiation detector
US5309097A (en) * 1992-04-15 1994-05-03 Enrique Rodriguez Video display terminal magnetic field detector
US6346692B1 (en) * 1999-09-20 2002-02-12 Agere Systems Guardian Corp. Adaptive microwave oven
US20100290169A1 (en) * 2006-08-25 2010-11-18 Powerwave Technologies Sweden Ab Active lightning protection
US10009965B2 (en) 2015-01-28 2018-06-26 Samsung Electronics Co., Ltd. Gas detection apparatus, cooking apparatus, and method of controlling the apparatuses
US20220170868A1 (en) * 2020-12-02 2022-06-02 Shimadzu Corporation X-ray imaging apparatus
US12256481B2 (en) 2019-07-09 2025-03-18 BSH Hausgeräte GmbH Household microwave appliance having mode variation apparatus

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1145400A (en) 1978-02-16 1983-04-26 Raymond A. Laperle Ground-isolated electrostatic field detector
DE3236290C2 (de) * 1982-09-30 1985-08-08 Bosch-Siemens Hausgeräte GmbH, 7000 Stuttgart Vorrichtung zum Überwachen des Schließzustandes von Türen an Mikrowellenöfen
JPH0179471U (enrdf_load_stackoverflow) * 1987-11-16 1989-05-29
EP2152047A1 (de) 2008-08-04 2010-02-10 Topinox Sarl Sicherheitseinrichtung zur Detektierung von Leckagestrahlung
DE102019207978A1 (de) 2019-05-30 2020-12-03 BSH Hausgeräte GmbH Haushalts-Mikrowellengerät mit Detektionseinrichtung zur Erfassung von Mikrowellen-Leckagestrahlung
DE102020208535A1 (de) 2020-07-08 2022-01-13 BSH Hausgeräte GmbH Feststellen von Funkenüberschlägen während eines Mikrowellen-Behandlungsablaufs eines Haushalts-Mikrowellengeräts

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3063010A (en) * 1960-04-25 1962-11-06 Alfred W Richardson Microwave dosimeter
US3350702A (en) * 1965-01-26 1967-10-31 Ruth A Herman Infrared detection system for fault isolation and failure prediction

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3063010A (en) * 1960-04-25 1962-11-06 Alfred W Richardson Microwave dosimeter
US3350702A (en) * 1965-01-26 1967-10-31 Ruth A Herman Infrared detection system for fault isolation and failure prediction

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3746824A (en) * 1972-08-07 1973-07-17 Gen Electric Microwave oven leakage radiation detecting device
US3900713A (en) * 1973-03-26 1975-08-19 Micro Devices Corp Thermal limiter construction and electrical switch and system utilizing the same
US4253092A (en) * 1979-04-19 1981-02-24 Connah John F Jun Microwave leakage detector
US4529855A (en) * 1982-04-12 1985-07-16 Henry Fleck Microwave radiation detector
US5309097A (en) * 1992-04-15 1994-05-03 Enrique Rodriguez Video display terminal magnetic field detector
US5311130A (en) * 1992-04-15 1994-05-10 Rad Devices, Inc. Electromagnetic field radiation detector having audible and visual indicators for detecting frequencies within the range of five hertz to four hundred kilohertz
US6346692B1 (en) * 1999-09-20 2002-02-12 Agere Systems Guardian Corp. Adaptive microwave oven
US20100290169A1 (en) * 2006-08-25 2010-11-18 Powerwave Technologies Sweden Ab Active lightning protection
US8599529B2 (en) * 2006-08-25 2013-12-03 P-Wave Holdings, Llc Active lightning protection
US10009965B2 (en) 2015-01-28 2018-06-26 Samsung Electronics Co., Ltd. Gas detection apparatus, cooking apparatus, and method of controlling the apparatuses
US12256481B2 (en) 2019-07-09 2025-03-18 BSH Hausgeräte GmbH Household microwave appliance having mode variation apparatus
US20220170868A1 (en) * 2020-12-02 2022-06-02 Shimadzu Corporation X-ray imaging apparatus
CN114577821A (zh) * 2020-12-02 2022-06-03 株式会社岛津制作所 X射线摄像装置
US11662322B2 (en) * 2020-12-02 2023-05-30 Shimadzu Corporation X-ray imaging apparatus

Also Published As

Publication number Publication date
DE2029559B2 (de) 1974-01-17
DE2029559C3 (de) 1974-08-08
FR2080555A3 (enrdf_load_stackoverflow) 1971-11-19
FR2080555B3 (enrdf_load_stackoverflow) 1973-10-19
GB1298163A (en) 1972-11-29
JPS541939B1 (enrdf_load_stackoverflow) 1979-01-31
DE2029559A1 (de) 1971-07-29

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