GB2081870A - Automatic shutdown apparatus for domestic gas cookstoves - Google Patents

Automatic shutdown apparatus for domestic gas cookstoves Download PDF

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Publication number
GB2081870A
GB2081870A GB8026226A GB8026226A GB2081870A GB 2081870 A GB2081870 A GB 2081870A GB 8026226 A GB8026226 A GB 8026226A GB 8026226 A GB8026226 A GB 8026226A GB 2081870 A GB2081870 A GB 2081870A
Authority
GB
United Kingdom
Prior art keywords
gas
motor
flame
transistor
automatic shutdown
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.)
Granted
Application number
GB8026226A
Other versions
GB2081870B (en
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.)
GUOJANG HUANG
Original Assignee
GUOJANG HUANG
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
Application filed by GUOJANG HUANG filed Critical GUOJANG HUANG
Priority to GB8026226A priority Critical patent/GB2081870B/en
Publication of GB2081870A publication Critical patent/GB2081870A/en
Application granted granted Critical
Publication of GB2081870B publication Critical patent/GB2081870B/en
Priority to SG367/84A priority patent/SG36784G/en
Priority to HK637/84A priority patent/HK63784A/en
Priority to MY639/85A priority patent/MY8500639A/en
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24C—DOMESTIC STOVES OR RANGES ; DETAILS OF DOMESTIC STOVES OR RANGES, OF GENERAL APPLICATION
    • F24C3/00—Stoves or ranges for gaseous fuels
    • F24C3/12—Arrangement or mounting of control or safety devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23K—FEEDING FUEL TO COMBUSTION APPARATUS
    • F23K5/00—Feeding or distributing other fuel to combustion apparatus
    • F23K5/002—Gaseous fuel
    • F23K5/007—Details
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
    • F23N5/12—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods
    • F23N5/123—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods using electronic means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2229/00—Flame sensors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2231/00—Fail safe
    • F23N2231/06—Fail safe for flame failures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2235/00—Valves, nozzles or pumps
    • F23N2235/12—Fuel valves
    • F23N2235/14—Fuel valves electromagnetically operated

Abstract

A gas valve (not shown) between a gas inlet 01 and outlet 02 is operated by turning of a shaft 1a by means of a knob 1. in addition, an electric motor 5 is connected with the shaft by gears 4a, 4b. An actuator 2b on the shaft actuates a microswitch 31 to switch on the supply to the motor. An electrical circuit incorporates a flame-sensor and a relay which operates to cause the motor to turn off the gas valve when the flame being sensed is unintentionally extinguished. <IMAGE>

Description

SPECIFICATION Automatic shutdown apparatus for domestic gas cookstoves The present invention relates to an improved safety, automatic shutting means applied to house cookstoves which can shut off the gas immediately when the fire is undesirably extinguished by some causes, and give out a warning signal simultaneously.
The currently available gas fuels, including compressed oil gas (i.e. liquefied propane or butane stored in steel bottles for use) coal gas and natural gas (the latter two types supplied by gas main) are the most widely used means for domestic cooking and heating except for electricity. Gas fuels, however, are highly inflammable, so that escapes are liable to cause explosions and fires and, in addition, they are liable to cause suffocation, or, in the case of coal gas, particularly, gas poisoning. Coal gas contains carbon monoxide, which is so poisonous that even a concentration as low as 0.03% in the atmosphere can cause death. Oil gas and natural gas are not poisonous but can cause suffocation.Investigating the causes of such disasters, we find more often than not, they result from the unnoticed extinguishing of a burning flame for example due to wind, or the overflowing of boiling water, so that the gas escapes.
The present invention provides automatic shutdown apparatus for a domestic gas cooker for shutting off the gas supply when a flame is unintentionally extinguished, the apparatus comprising a gas valve, manual means for controlling the gas valve, power means including an electric motor for controlling the gas valve and a flame-sensing electrical device for switching on the motor to turn off the gas valve when the flame is extinguished.
Reference is made to the accompanying drawings, wherein Figure 1 is the perspective view of shutdown apparatus according to this invention; Figure 2 is a wiring diagram showing how the apparatus is operated; and Figure 3 is a detailed circuit diagram of an extinguishing controller of the apparatus.
With reference now to the drawings, particularly Figure 1 thereof, gas enters the shutdown apparatus through an inlet 01, and leaves from an outlet 02 to reach the nozzles (not shown in the drawing) where it is burned. A knob 1 controls opening and closing the gas passage by turning of a shaft to operate a valve (not shown). The passage is opened when knob 1 is turned in a clockwise direction, and closed when the latter is turned counter-clockwise. An actuator 2 has a collar 2a coaxially mounted on the same shaft la and an actuating arm 2b which actuates a microswitch 31. When the knob 1 is turned clockwise, the arm 2b contacts a touchtriggered-member 311 of the micro-switch and switches on an electric current to an extinguishing controller (6) (See Figure 2).A flame sensor 7 is provided and this switches off the current to the controller 6 when heated by a flame but switches on the cirrrent on coolina. if the flame is extinguished. A current is then fed to a motor 5 which turns the shaft 1a counterclockwise to switch off the gas, the motor being connected to the shaft through gears 4a, 4b.
The actuating arm 2a is, therefore, moved away from the microswitch 31 to cut off the electricity supply to the motor 5. An electrically operated audible alarm 9, such as a buzzer, is operated. The knob 1 is provided with a touch-triggered-grounding means 11 whereby the user can earth it with a mere touch (See Figure 3). This earths relay 8 and prevents its operation to switch on the electricity supply when the knob is being moved to control the outflow of gas.
Referring to Figure 3, when the gas stove is being used, earthing is accomplished by means of "flameto-ground", or by touching touch-triggeredgrounding means 11 so that either G or D becomes potentially negative with respect to the ground.
Once the base of transistor Q1 gains a negative potential, the emitter and the collector will be electrically connected to enable the collector to send out a positive signal to the base of transistor Q2, which base, after having been positively biased in this way, functions to allow a current to cross the junction between the emitter and collector of transistor Q2, and earths to counteract the base bias which is provided by resistor R2 to transistor Q3, therefore providing a bias for the base of transistor Q3 insomuch that a current may flow through resistors R3, R2 and the junction between collector and the emitter of transistor Q2 to ground to build up a complete loop circuit. While transistor Q3, lacks base bias the relay 8, does not operate.When the flame goes out, D (or G) is no longer earthed and the base of transistor Qi fails to obtain a negative bias, so it does not work. Neither does transistor Q2. As a result, a current passes resistor R3 and R2 to bias the base of transistor Q3 to allow a current to cross the junction between the collector and emitter thereof to enter relay 8 to result in the connection of point o to point b. An output of 12 volt DC thus pass through the (o, b) connection to provide the power for the operation of the motor 5 to switch off the gas.
A timing control device K is provided (Figure 2) to control the duration of burning. This is inserted between the power source and motor 5 and operates to actuate the motor both for switch-on and switchoff of the gas supply.
The above described apparatus can be inexpensively manufactured because of its simple construction. Use of electricity is confined to the transient moments in which the motor 5 is operated, so that the cost of operation is negligibile. As shown, a battery is used to supply the power, but a rectified 12 volt supply may be obtained from AC mains.
1. Automatic shutdown apparatus for a domestic gas cooker for shutting off the gas supply when a flame is unintentionally extinguished, the apparatus comprising a gas valve, manual means for controlling the gas valve, power means including an electric motor for controlling the gas valve and a flame sensing electrical device for switching on the motor
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Automatic shutdown apparatus for domestic gas cookstoves The present invention relates to an improved safety, automatic shutting means applied to house cookstoves which can shut off the gas immediately when the fire is undesirably extinguished by some causes, and give out a warning signal simultaneously. The currently available gas fuels, including compressed oil gas (i.e. liquefied propane or butane stored in steel bottles for use) coal gas and natural gas (the latter two types supplied by gas main) are the most widely used means for domestic cooking and heating except for electricity. Gas fuels, however, are highly inflammable, so that escapes are liable to cause explosions and fires and, in addition, they are liable to cause suffocation, or, in the case of coal gas, particularly, gas poisoning. Coal gas contains carbon monoxide, which is so poisonous that even a concentration as low as 0.03% in the atmosphere can cause death. Oil gas and natural gas are not poisonous but can cause suffocation.Investigating the causes of such disasters, we find more often than not, they result from the unnoticed extinguishing of a burning flame for example due to wind, or the overflowing of boiling water, so that the gas escapes. The present invention provides automatic shutdown apparatus for a domestic gas cooker for shutting off the gas supply when a flame is unintentionally extinguished, the apparatus comprising a gas valve, manual means for controlling the gas valve, power means including an electric motor for controlling the gas valve and a flame-sensing electrical device for switching on the motor to turn off the gas valve when the flame is extinguished. Reference is made to the accompanying drawings, wherein Figure 1 is the perspective view of shutdown apparatus according to this invention; Figure 2 is a wiring diagram showing how the apparatus is operated; and Figure 3 is a detailed circuit diagram of an extinguishing controller of the apparatus. With reference now to the drawings, particularly Figure 1 thereof, gas enters the shutdown apparatus through an inlet 01, and leaves from an outlet 02 to reach the nozzles (not shown in the drawing) where it is burned. A knob 1 controls opening and closing the gas passage by turning of a shaft to operate a valve (not shown). The passage is opened when knob 1 is turned in a clockwise direction, and closed when the latter is turned counter-clockwise. An actuator 2 has a collar 2a coaxially mounted on the same shaft la and an actuating arm 2b which actuates a microswitch 31. When the knob 1 is turned clockwise, the arm 2b contacts a touchtriggered-member 311 of the micro-switch and switches on an electric current to an extinguishing controller (6) (See Figure 2).A flame sensor 7 is provided and this switches off the current to the controller 6 when heated by a flame but switches on the cirrrent on coolina. if the flame is extinguished. A current is then fed to a motor 5 which turns the shaft 1a counterclockwise to switch off the gas, the motor being connected to the shaft through gears 4a, 4b. The actuating arm 2a is, therefore, moved away from the microswitch 31 to cut off the electricity supply to the motor 5. An electrically operated audible alarm 9, such as a buzzer, is operated. The knob 1 is provided with a touch-triggered-grounding means 11 whereby the user can earth it with a mere touch (See Figure 3). This earths relay 8 and prevents its operation to switch on the electricity supply when the knob is being moved to control the outflow of gas. Referring to Figure 3, when the gas stove is being used, earthing is accomplished by means of "flameto-ground", or by touching touch-triggeredgrounding means 11 so that either G or D becomes potentially negative with respect to the ground. Once the base of transistor Q1 gains a negative potential, the emitter and the collector will be electrically connected to enable the collector to send out a positive signal to the base of transistor Q2, which base, after having been positively biased in this way, functions to allow a current to cross the junction between the emitter and collector of transistor Q2, and earths to counteract the base bias which is provided by resistor R2 to transistor Q3, therefore providing a bias for the base of transistor Q3 insomuch that a current may flow through resistors R3, R2 and the junction between collector and the emitter of transistor Q2 to ground to build up a complete loop circuit. While transistor Q3, lacks base bias the relay 8, does not operate.When the flame goes out, D (or G) is no longer earthed and the base of transistor Qi fails to obtain a negative bias, so it does not work. Neither does transistor Q2. As a result, a current passes resistor R3 and R2 to bias the base of transistor Q3 to allow a current to cross the junction between the collector and emitter thereof to enter relay 8 to result in the connection of point o to point b. An output of 12 volt DC thus pass through the (o, b) connection to provide the power for the operation of the motor 5 to switch off the gas. A timing control device K is provided (Figure 2) to control the duration of burning. This is inserted between the power source and motor 5 and operates to actuate the motor both for switch-on and switchoff of the gas supply. The above described apparatus can be inexpensively manufactured because of its simple construction. Use of electricity is confined to the transient moments in which the motor 5 is operated, so that the cost of operation is negligibile. As shown, a battery is used to supply the power, but a rectified 12 volt supply may be obtained from AC mains. CLAIMS
1. Automatic shutdown apparatus for a domestic gas cooker for shutting off the gas supply when a flame is unintentionally extinguished, the apparatus comprising a gas valve, manual means for controlling the gas valve, power means including an electric motor for controlling the gas valve and a flame sensing electrical device for switching on the motor to turn off the gas valve when the flame is extinguished.
2. Automatic shutdown apparatus according to Claim 1, including an electrically operated alarm device which is operated when the motor is operated.
3. Automatic shutdown apparatus according to Claim 1 or 2 including a controller having circuit means including a relay, the relay being inoperable when said circuit is earthed, but when the earth connection is broken switches electrical current to the motor, the flame-sensing device serving to control said earth connection.
4. Automatic shutdown apparatus according to Claim 3 wherein said manual means serves to earth said circuit when the manual means is grasped by a person.
5. Automatic shutdown apparatus according to any preceding Claim including a switch actuable by said manual means to disconnect the motor from its electrical supply when the gas valve is turned off.
6. Automatic shutdown apparatus according to any preceding Claim wherein said motor is connected by gears to a shaft which is rotatable to operate the gas valve, said manual means being a knob on the shaft.
7. Automatic shutdown apparatus according to Claim 6 as appendant to Claim 5, where said switch is a microswitch actuable by an actuating arm mounted on said shaft.
8. Automatic shutdown apparatus according to any preceding Claim, including a timing control device for timing supply of electrical power to the motor to turn off the gas supply after a selected period.
9. Automatic shutdown apparatus for a domestic gas cooker constructed substantially as herein described with reference to the accompanying drawings.
GB8026226A 1980-08-12 1980-08-12 Automatic shutdown apparatus for domestic gas cookstoves Expired GB2081870B (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
GB8026226A GB2081870B (en) 1980-08-12 1980-08-12 Automatic shutdown apparatus for domestic gas cookstoves
SG367/84A SG36784G (en) 1980-08-12 1984-05-08 Automatic shutdown apparatus for domestic gas cookstoves
HK637/84A HK63784A (en) 1980-08-12 1984-08-16 Automatic shutdown apparatus for domestic gas cookstoves
MY639/85A MY8500639A (en) 1980-08-12 1985-12-30 Automatic shutdown apparatus for domestic gas cookstoves

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8026226A GB2081870B (en) 1980-08-12 1980-08-12 Automatic shutdown apparatus for domestic gas cookstoves

Publications (2)

Publication Number Publication Date
GB2081870A true GB2081870A (en) 1982-02-24
GB2081870B GB2081870B (en) 1984-03-07

Family

ID=10515397

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8026226A Expired GB2081870B (en) 1980-08-12 1980-08-12 Automatic shutdown apparatus for domestic gas cookstoves

Country Status (4)

Country Link
GB (1) GB2081870B (en)
HK (1) HK63784A (en)
MY (1) MY8500639A (en)
SG (1) SG36784G (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2761459A1 (en) * 1997-03-28 1998-10-02 Gaz De France Gas cooker burner safety system
US6843243B2 (en) * 2002-10-11 2005-01-18 General Electric Company Motorized gas lockout valve for gas range
US20110271880A1 (en) * 2010-05-04 2011-11-10 Carrier Corporation Redundant Modulating Furnace Gas Valve Closure System and Method
US20230243509A1 (en) * 2020-06-13 2023-08-03 Butterfly Gandhimathi Appliances Limited Safety knobs for gas cooktops

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2761459A1 (en) * 1997-03-28 1998-10-02 Gaz De France Gas cooker burner safety system
US6843243B2 (en) * 2002-10-11 2005-01-18 General Electric Company Motorized gas lockout valve for gas range
US20110271880A1 (en) * 2010-05-04 2011-11-10 Carrier Corporation Redundant Modulating Furnace Gas Valve Closure System and Method
US20230243509A1 (en) * 2020-06-13 2023-08-03 Butterfly Gandhimathi Appliances Limited Safety knobs for gas cooktops

Also Published As

Publication number Publication date
HK63784A (en) 1984-08-24
GB2081870B (en) 1984-03-07
SG36784G (en) 1985-04-04
MY8500639A (en) 1985-12-31

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Legal Events

Date Code Title Description
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee