US3609732A - Gas responsive switching device - Google Patents

Gas responsive switching device Download PDF

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Publication number
US3609732A
US3609732A US39354A US3609732DA US3609732A US 3609732 A US3609732 A US 3609732A US 39354 A US39354 A US 39354A US 3609732D A US3609732D A US 3609732DA US 3609732 A US3609732 A US 3609732A
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US
United States
Prior art keywords
relay
gas
coil
electrodes
power source
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
US39354A
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English (en)
Inventor
Riichiro Kasahara
Yuichi Shimakawa
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.)
New Cosmos Electric Co Ltd
Original Assignee
New Cosmos Electric Co Ltd
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 JP4978869U external-priority patent/JPS4810857Y1/ja
Priority claimed from JP5264269U external-priority patent/JPS4810858Y1/ja
Priority claimed from JP6608369U external-priority patent/JPS4838224Y1/ja
Application filed by New Cosmos Electric Co Ltd filed Critical New Cosmos Electric Co Ltd
Application granted granted Critical
Publication of US3609732A publication Critical patent/US3609732A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
    • G01N27/122—Circuits particularly adapted therefor, e.g. linearising circuits
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00—Fire alarms; Alarms responsive to explosion
    • G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
    • G08B17/117—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means by using a detection device for specific gases, e.g. combustion products, produced by the fire

Definitions

  • ABSTRACT A gas responsive switching device for detecting gas concentrations in air which uses a heated semiconductor having two electrodes embedded therein, a resistor connected in series with the electrodes and across a power source, a thyristor and relay coil connected in series across a source of power and a connection between the control electrode and a tap on said resistor.
  • the device may also include a second relay having a coil connected in series with said voltage divider and adjusted so that both relays operate at two different gas concentrations.
  • GAS RESPONSIV E SWITCHING DEVICE This invention relates to a switching device for performing a switching operation upon the detection of an inflammable gas and more specifically to a novel and improved circuit which will perform a normal relay operation in response to the electrical output of an element detecting the presence of inflammable gas.
  • Pending US. application for Pat. Ser. No. 10,848, entitled GAS ALARM DEVICE discloses a metal oxide semiconductor element having a high sensitivity to the presence of inflammable gas.
  • the element includes I two coils formed of metal wire and disposed in spaced parallel relationship.
  • the metal oxide semiconductor surrounds and encloses the two coils and may be formed of materials such as SnO ZnO, Nb,0,, Ta,0 V TiO,, and Fe o each of which has a resistance characteristic which varies materially in the presence of an inflammable gas.
  • its surface temperature is maintained in the range of 50 C. to 300 C. by passing an appropriate heating current through one or both of the coils.
  • a voltage of the order of 100 volts is applied between the coils, and when the element is in the presence of an inflammable gas, the current flowing between the coils increases materially.
  • One object of the invention raises in the utilization of the above mentioned inflammable gas detecting element to operate a relay or switching circuit for opening and closing appropriate contacts having a sufficient current capacity to control any desired apparatus.
  • One of a circuit in accordance with the invention includes the aforesaid inflammable gas detecting element, a relay, a thyristor or silicon controlled rectifier, voltage dividing means, one or more sources of a relatively low voltage and one or more sources of a relatively high voltage. Atleast one of the coils of the detecting element is connected to the low voltage source. A series circuit including the two coils of the detecting element and said voltage dividing means, and a second series circuit including the coil of said relay and said thyristor element are connected to the high voltage source. The gate electrode of the thyristor element is connected to a tap on the voltage dividing means.
  • Apparatus which may be controlled may include an illuminating device, ventilating means for exhausting the inflammable gas or valving means to shut off the supply of inflammable gas.
  • Another object of the invention resides in the provision of a novel and improved circuit including an inflammable gas detector which includes means for adjusting the detector to respond to a selected gas concentration in the air.
  • the gas concentration required to operate the relay in each device will not necessarily be uniform.
  • the device may readily be adjusted to respond to a selected ro predetermined gas concentration.
  • the gas concentration at which the device will respond can be readily adjusted and selected by adjusting the tap on the voltage dividing means.
  • Another object of the invention resides in the provision of a novel and improved combination of an inflammable gas detecting element and associated circuitry which will afford stable operation with increased sensitivity.
  • the detecting element is provided with two coiled electrodes
  • the utilization of the coiledrelectrodes merely facilitates manufacture and the detector will function by utilizing just one of the coils to heat the semiconductor body so that the other coil could be replaced with a straight wire or plate which would not afford any heating function.
  • heating current was supplied to only one of the coils, and the ends of the other coil were generally connected one to the other so that it functioned as a single electrode.
  • the application of heating current to only one of the coils results in the heating of only one part of the semiconductor body and the unheated portion of the semiconductor bodyis not very active. Accordingly, a high degree of sensitivity and stability was not attained.
  • heating current is supplied to both coils which produces uniform heating of the semiconductor body and thereby affords a high degree of stability and sensitivity in the detection of gas.
  • Another object of the invention resides in the provision of a novel and improved electrical apparatus utilizing a single gas detecting element and incorporating separate relays which can be adjusted to operate in response to different gas concentrations. This is attained by the utilization of an additional relay in a series circuit consisting of the two coils of the detecting element and the voltage dividing means.
  • the gas concentration at which the latter relay operates can be determined by adjusting the resistance value of the series circuit as a whole.
  • the basic relay would be adjusted by properly setting the tap on the voltage divider. With this arrangement one relay could be used to operate a ventilating fan when the gas concentration reached one selected level while the other relay would operate an alarm should the gas concentration exceed a predetermined higher level.
  • a still further object'of the invention resides in the provision of means which afford an indication of the operating or nonoperating positions of the relay.
  • a light emitting discharge tube such as a neon lamp or the like is connected in parallel with-the relay.
  • the tube is arranged so that it will not be illuminated when the current through-the relay coil is small but will be illuminated when the current increases to a value sufficient to operate the relay. Under this condition the voltage drop across the relay increases sufficiently to operate the neon lamp.
  • FIG. 1 is an enlarged perspective view of an inflammable gas detecting element used with this invention and in which the semiconductor body is shown in outline in order to illustrate the internal structure;
  • FlG. 2 is a transverse sectional view of a gas detecting element as illustrated in FlG. l;
  • FlG. 3 is a side elevational view in partial section of the mounting means for the detecting element shown in FIGS. 1 and 2;
  • FIG. 4 is a circuit diagram of one embodiment of a gas responsive device in accordance with the invention wherein heating current is supplied to both coils of the detecting element;
  • FIG. 5 is a circuit diagram of another embodiment of the invention utilizing two relays operable at different gas concentration levels.
  • FIG. 6 is still another embodiment of the invention wherein neon tubes are interconnected with the relays to indicate the operational state of the relay.
  • the gas detecting element used in accordance with this invention is illustrated in FIGS. 1 and 2.
  • the detecting element comprises a pair of coils l and 2 formed of a relatively nonoxidizable metal wire such as platinum, palladium or platinum-iridium alloy.
  • the coils are disposed in parallel grooves 4 and 5 formed in opposing surfaces of a block 3, the latter being formed of a heat proof electrically insulating inorganic oxide such as A1 0 SiO or BeO.
  • An inorganic high melting point adhesive 6 and 7 is used to secure the coils l and 2 in the grooves.
  • the adhesive is preferably formed of a material such as Na,0 intermixed'with at least one of the following materials, namely, K 0, CaF
  • A1 0 Ba O and SiO With this arrangement the coils are fixed in predetermined parallel relationship. It is to be noted that only a portion of each of the coils is embedded in the adhesive so that the major portion of each coil is exposed.
  • the block 3 and the coils l and 2 are then enclosed within a metal oxide semiconductor material 8 as will be observed more clearly in FIG. 2.
  • the semiconductor material is sensitive at high temperatures to inflammable gas, and the completed unit forms a blocklike structure with the ends of the coils 1 and 2 extending from the structure and constituting lead wires 9, l0, 1 l and 12.
  • the metal oxide semiconductor material 8 is preferably formed of SnO ZnO, Nb O, Ta O V TiO or Pep, When these materials contact an flammable gas and are heated to temperatures of the order of 50 C. to 300 C., the gas removes oxygen ions from the semiconductor material and oxidizes the semiconductor material. This causes the cations and anions within the semiconductor body to become unbalanced with the result that the resistance of the semiconductor material varies.
  • the semiconductor element as illustrated in FIGS. 1 and 2 by then mounted within a housing as illustrated in FIG. 3. More specifically, the lead wires 9, 10 11 and 12 are connected to supporting rods l3, 14, 15 and 16 formed of a conducting material and which are carried by a stem 17.
  • the stem 17 is formed of an insulating material such as plastic or the like, and the conductors 13 through 16 protrude from the bottom face of the stem to fonn connecting prongs.
  • the coils 1 and 2 are first connected to the conductors 9 through 12.
  • the grooves 4 and 5 of the insulating 3 are then coated with the adhesive agent 6 and 7 whereupon the block is inserted between the coils I and 2.
  • the coils are then heated by passing a current through the supporting rods l3, l4, and 15, 16 to melt the adhesive and permanently fix the coils 1 and 2 to the block 3.
  • the coils 1 and 2 and the block 3 are then enclosed within a nonsintered gas sensitive metal oxide semiconductor.
  • the coils are then reheated to sinter the metal oxide semiconductor and thus form the completed detector. Inasmuch as the heating current required during actual use of the detector is substantially less then the heating current required for fabrication, neither the adhesive nor the metal oxide semiconductor will be adversely affected by the heat required for actual use of the detector.
  • the detecting element is enclosed by a cylindrical metal wire mesh 18 and the upper end of the mesh is closed by a metal cap 19.
  • the stem 17 has an upper portion 20 of relatively small diameter to receive the cylindrical mesh and a lower portion 21 of greater diameter.
  • the mesh 18 fits within a groove 22 formed in the lower portion 21 and is secured thereon by a suitable adhesive.
  • the electrical circuit includes a power transformer generally denoted by the numeral 34 having a binary winding 35 adapted to be energized by an alternating current voltage of 110 volts or 220 volts as may be desired.
  • the transformer further includes a pair of secondary windings 36 and 37, each of which generate approximately 1.5 volts and a secondary winding 38 which generates approximately 100 volts.
  • the windings 36 and 37 are connected to the coils 32 and 33, respectively, to heat the element 31.
  • One end of the secondary winding 38 is interconnected with the secondary winding 37 and one side of the secondary winding 36 is connected through a voltage divider 39 to the other side of the winding 38.
  • This arrangement produces a series circuit including the winding 38, the coils 33 and 32, and the voltage divider 39.
  • the relay is provided with contacts 45 which are normally open and which close when the coil 40 is energized. If desired, a capacitor 46 may be connected in parallel with the relay 40 to minimize the ripple component of the current used to energize the relay.
  • the contacts 45 may then be utilized to control electrical apparatus connected thereto.
  • the specific gas threshold at which the thyristor 41 will be fired can be selected by adjusting the position of the tap 44 and the voltage divider 39. Since alternating current is used to operate the relay, when the concentration of gas falls below the threshold, the voltage at the tap 44 will fall below the firing point of the thyristor, and accordingly, the thyristor will return to its maximum impedance state and deenergize the relay.
  • FIG. 5 In the embodiment of the invention as illustrated in FIG. 5, components corresponding to components in FIG. 4 have been denoted by like numerals.
  • the transformer 34 is provided with a single low voltage secondary winding 37 which provides heating current to the coil 33 of the detecting element 31.
  • the relay 51 has one end of the coil connected to the coil 32 while the other end of the relay coil is connected to the voltage divider 39 having a variable resistor 53 connected in parallel therewith.
  • the operation of this circuit is substantially the same as the circuit shown in FIG. 4 in that the relay 40 will operate when the inflammable gas concentration reaches a predetermined threshold and produces a voltage on the tap 44 sufficient to fire the thyristor 41.
  • the relay 51 connected in series with the detecting element 31 will be operated to close the contacts 52 when sufficient current flows through the detector 31 as a result of increases gas concentration.
  • the threshold at which the relay 51 will operate can be controlled by the adjustment of resistor 53.
  • the tap 44 can be adjusted so that the relay 40 will be operated at a selected gas concentration.
  • the two relays can be operated at different gas thresholds.
  • This arrangement is particularly advantageous in that one relay can initiate operation of a ventilating fan when the gas concentration attains a first level and then should the concentration continue to increase, the second relay can operate an alarm device or a valve closing mechanism associated with the gas supply.
  • FIG. 6 The embodiment of the invention illustrated in FIG. 6 is similar to that of FIG. 5 except that a neon lamp 54 and series resistor 55 are connected in parallel with the relay 40. A'filtering condenser may also be utilized in parallel with the relay as illustrated. A second neon lamp 56 and a series resistor 57 are connected effectively in parallel with the relay coil 51. It is preferable, however, to use a variable resistor 58 connected in parallel with the resistor 53 and to connect the lower end of the resistor 57 to an adjustable tap on the resistor 58.
  • the neon lamp 54 When the neon lamp 54 is illuminated by reason of the firing of the thyristor 41, an immediate indication is provided showing that the relay 40 has been operated.
  • the neon lamp 56 will be illuminated when the resistance of the semiconductor 42 of the detector 31 falls below a predetermined value. Such value however can be determined by adjusting the resistor 58. In this way the lamp 56 can be arranged to be illuminated coincidentally with the operation of the relay 51.
  • a gas responsive device comprising an inflammable gas detecting element having two electrodes at least one of which is a heating electrode and a metal oxide semiconductor enclosing and contacting both electrodes, said semiconductor having a resistance variable in response to the concentration of said gas in air, a first power source connected to said heating electrode for heating the said semiconductor, a second power source, a voltage divider including a tap thereon, a connection from one of said electrodes to one side of the second power source, means including said voltage divider connecting the other of said electrodes to the other side of said second power source, a relay having a coil and contacts operated by said coil, a thyristor having a control electrode, said relay coil and thyristor being connected in series across said second power source and a connection between said control electrode and the tap on said voltage divider.
  • a gas responsive device wherein said other electrode is a heating electrode and said device includes a third power source connected to said other electrode whereby both electrodes are heated.
  • a gas responsive device according to claim 1 wherein said voltage divider is a resistor and said tap is adjustably positioned on said resistor.
  • a gas responsive device including a second relay having a coil and contacts, the last said coil being connected in series with said voltage divider and is energized by current flowing through said detecting element.
  • a gas responsive device including a light emissive discharge lamp connected in parallel with said relay coil.
  • a gas responsive device including a light emissive discharge lamp connected in parallel with the coil of said secondary relay.

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  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Emergency Management (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Business, Economics & Management (AREA)
  • Life Sciences & Earth Sciences (AREA)
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  • General Health & Medical Sciences (AREA)
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  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
US39354A 1969-05-28 1970-05-21 Gas responsive switching device Expired - Lifetime US3609732A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP4978869U JPS4810857Y1 (enExample) 1969-05-28 1969-05-28
JP5264269U JPS4810858Y1 (enExample) 1969-06-05 1969-06-05
JP6608369U JPS4838224Y1 (enExample) 1969-07-11 1969-07-11

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DE (1) DE2025770C3 (enExample)
FR (1) FR2050400A1 (enExample)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3750123A (en) * 1971-11-01 1973-07-31 T J Connelly Constr Co Inc Smoke sensing circuit with battery standby
US3786462A (en) * 1971-03-18 1974-01-15 Trw Inc Carbon monoxide alarm for automobiles
DE2437352A1 (de) * 1973-08-03 1975-02-13 Nohmi Bosai Kogyo Co Ltd Vorrichtung zum nachweis von kohlenmonoxyd
US3879717A (en) * 1974-06-19 1975-04-22 K F Ind Inc Portable methane monitor and alarm system
US3882478A (en) * 1973-05-14 1975-05-06 Malgard Corp Gas and smoke alarm
US3930247A (en) * 1974-09-06 1975-12-30 Avco Corp Open screen smoke detector and circuit
US3951603A (en) * 1972-07-08 1976-04-20 Hitachi, Ltd. Gas-sensor element and method for detecting reducing gas or oxygen gas
US3953173A (en) * 1972-07-08 1976-04-27 Hitachi, Ltd. Gas-sensor element and method for detecting oxidizable gas
US4001804A (en) * 1974-11-25 1977-01-04 I-T Safety Enterprises Limited Ground fault protection for electrical power distribution systems
US4047893A (en) * 1973-07-24 1977-09-13 C.S.S. Container Storage Service Establishment Apparatus for measuring the alcohol content in human breath
DE2833922A1 (de) 1978-07-17 1980-02-07 Cerberus Ag Gas- und/oder brandmeldeanlage
US4196427A (en) * 1976-07-28 1980-04-01 Rudberg Harry I A Method and apparatus for measuring low concentrations of chlorine and chlorine oxide
US4295028A (en) * 1979-02-23 1981-10-13 Sharp Kabushiki Kaisha Combination of gas sensor controlled cooking utensil and gas leak alarm
US4334258A (en) * 1980-06-23 1982-06-08 Seeman Jeffrey L Explosion prevention control system for a fuel-gas burning automatic ignition appliance and associated gas distribution system
US4767913A (en) * 1986-05-15 1988-08-30 Amoco Corporation Automatic gas detector for arc welder
US5576739A (en) * 1992-06-18 1996-11-19 Phy-Con. Inc. Carbon monoxide safety system
US20080074821A1 (en) * 2006-09-23 2008-03-27 Bernd Kammerer Trigger circuit for an electromagnetic actuator
EP1959252A1 (en) * 2007-02-16 2008-08-20 Dometic Corporation Gas arrestor system
US20080284579A1 (en) * 2007-05-15 2008-11-20 David Contreras Carbon monoxide safety system

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1451231A (en) * 1973-03-30 1976-09-29 Nat Res Dev Gas sensitive devices
DE2408218C3 (de) * 1974-02-21 1983-11-03 Ehlen, Karl Josef, Dr., 5000 Köln Schaltungsanordnung zum Nachweis von Gasen
NL182511C (nl) * 1974-08-27 1988-03-16 Westfaelische Berggewerkschaft Werkwijze voor de bepaling van het gehalte van koolmonoxyde in een gasmengsel door meting van de elektrische weerstand van een of meer metaaloxyde-halfgeleiders en meettoestel voor ten uitvoerlegging van de werkwijze.
DE2829931C2 (de) * 1978-07-07 1985-11-21 Auergesellschaft Gmbh, 1000 Berlin Tragbares Gasmeß- und Warngerät

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3786462A (en) * 1971-03-18 1974-01-15 Trw Inc Carbon monoxide alarm for automobiles
US3750123A (en) * 1971-11-01 1973-07-31 T J Connelly Constr Co Inc Smoke sensing circuit with battery standby
US3951603A (en) * 1972-07-08 1976-04-20 Hitachi, Ltd. Gas-sensor element and method for detecting reducing gas or oxygen gas
US3953173A (en) * 1972-07-08 1976-04-27 Hitachi, Ltd. Gas-sensor element and method for detecting oxidizable gas
US3882478A (en) * 1973-05-14 1975-05-06 Malgard Corp Gas and smoke alarm
US4047893A (en) * 1973-07-24 1977-09-13 C.S.S. Container Storage Service Establishment Apparatus for measuring the alcohol content in human breath
DE2437352A1 (de) * 1973-08-03 1975-02-13 Nohmi Bosai Kogyo Co Ltd Vorrichtung zum nachweis von kohlenmonoxyd
US3879717A (en) * 1974-06-19 1975-04-22 K F Ind Inc Portable methane monitor and alarm system
US3930247A (en) * 1974-09-06 1975-12-30 Avco Corp Open screen smoke detector and circuit
US4001804A (en) * 1974-11-25 1977-01-04 I-T Safety Enterprises Limited Ground fault protection for electrical power distribution systems
US4196427A (en) * 1976-07-28 1980-04-01 Rudberg Harry I A Method and apparatus for measuring low concentrations of chlorine and chlorine oxide
DE2857262A1 (de) * 1978-07-17 1980-03-06 Cerberus Ag Gasmeldeanlage
DE2833922A1 (de) 1978-07-17 1980-02-07 Cerberus Ag Gas- und/oder brandmeldeanlage
US4295028A (en) * 1979-02-23 1981-10-13 Sharp Kabushiki Kaisha Combination of gas sensor controlled cooking utensil and gas leak alarm
US4334258A (en) * 1980-06-23 1982-06-08 Seeman Jeffrey L Explosion prevention control system for a fuel-gas burning automatic ignition appliance and associated gas distribution system
US4767913A (en) * 1986-05-15 1988-08-30 Amoco Corporation Automatic gas detector for arc welder
US5576739A (en) * 1992-06-18 1996-11-19 Phy-Con. Inc. Carbon monoxide safety system
US20080074821A1 (en) * 2006-09-23 2008-03-27 Bernd Kammerer Trigger circuit for an electromagnetic actuator
US7643266B2 (en) * 2006-09-23 2010-01-05 Erben Kammerer Kg Trigger circuit for an electromagnetic actuator
EP1959252A1 (en) * 2007-02-16 2008-08-20 Dometic Corporation Gas arrestor system
US20080198524A1 (en) * 2007-02-16 2008-08-21 Dometic Corporation Absorption gas arrestor system
AU2008200767B2 (en) * 2007-02-16 2011-08-25 Dometic, LLC Absorption gas arrestor system
US20080284579A1 (en) * 2007-05-15 2008-11-20 David Contreras Carbon monoxide safety system
US7683794B2 (en) 2007-05-15 2010-03-23 David Contreras Carbon monoxide safety system for preventing entry into a dwelling containing toxic gases

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Publication number Publication date
DE2025770C3 (de) 1979-07-26
DE2025770A1 (de) 1970-12-03
FR2050400A1 (enExample) 1971-04-02
DE2025770B2 (de) 1978-11-16

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