DESCRIPTION:
The electronic circuit part that shows in Fig:5 (for single oven)
and Fig:6 (for double oven), consist of
1) Temperature switching circuit that consist of Thermocouple
(TC) as a temperature sensor which is fitted in the burner top
from its bottom end and middle hole, clamp with burner
assembly, a comparator (CP1) and a potential divider for
reference value.
2) Magnetic switching circuit that consist of Magnetic sensor
(MS) which is fitted in the inner side of the oven (steel plate) of
each burner switch (knob) and a Button magnet which is fitted
in the back end of the each burner switch, a comparator (CP2)
and a potential divider for reference value. The magnetic sensor
is fitted in such a position by which the button magnet of the
burner switch is nearer to the magnetic sensor, when the switch
is in OFF position.
3) Gas sensor circuit that consist of LPG sensor (GS) which is
one type of semiconductor sensor of LPG, a comparator (CP3)
and a potential divider for reference value. The sensor is fitted in
such a position that its sensing portion is open to the
atmosphere.
4) An electronic timer circuit of 60 seconds ON time period.
5) An AND logic circuit that consist of 3-input AND gate.
6) A Motor control circuit that consist of a motor of 5V DC which
is connected to the motor-gear set and a limit switch.
7) An alarm circuit that consist of an alarm chip and a speaker.
8) A 6 Volt rechargeable battery (4X1.5V) as shown in Fig: 2.
9) A switch for On/Off the invented device as shown in Fig: 2.
10) A removable type 8 (eight) core flexible cable (both end
fitted with 8-point female connector) to connect the
thermocouple and magnetic switch from oven to invented device
through 8-point male connector as shown in Fig: 2.
The mechanical part as shown in Fig: 1, 2, 3 consist of
1) A multi-stage gear arrangement which consist of one worm
gear set connected with motor and six spur gears to form a high
turn's ratio as shown in Fig: 3.

2) A suitable cam mechanism consists of a driving cam (CAM-1)
and driven cam (CAM-2). The driving cam (CAM-1) is fixed with
the final shaft of the gear box and the driven cam (CAM-2)
which is of removable type, attached to the knob of the
regulator by press fit as shown in Fig: 1.
3) A lever (L1) connected to the final shaft which interns operate
a limit switch (LS) after each of one revolution as shown in
Fig: 2.
The whole arrangement that consist of electronic circuit (except
thermocouple, magnetic switch, and flexible cable), gearbox
(except driving and driven cam), limit switch, battery, speaker,
etc. are fitted in an air tight box as shown in Fig: 2. There is a
suitable clamp arrangement that hold the box when it is fitted
on above of the gas regulator as shown in Fig: 1.
Operation:
The whole operation of the circuit is based on digital logic i.e.'1'
for 'yes' or '5V DC' and '0' for 'NO' or '0V DC'. There are four
different cases in which the circuit operation is described below.

Table: - Truth table for operation of MEGSD
Case-1 (Regulator is ON, Oven is OFF, Flame is OFF):- When the
regulator is ON, if the oven switch is OFF the button magnet is
nearer to the magnetic sensor, then the comparator (CP-2)
gives logic output '0' . If the flame is OFF the mV generate by
the thermocouple is less than the reference value, then the
comparator (CP-1) gives a logic output '0'. As long as the oven
switch is off the output of the timer becomes logic '0'. So after
adding this three signals through AND circuit, the output is logic

'0', as shown in the Fig: 7. Which is the final trip signal. So the
motor control circuit gives a trip signal '0' which does not
operate the motor and regulator becomes stay in its ON
position.
Case-2 (Regulator is ON, Oven is ON, Flame is ON):- When the
regulator is ON, if we operate the oven switch to its ON position
the button magnet is in some distance from the magnetic
sensor, so comparator (CP-2) gives a logic output '1' and
simultaneously reset the timer. The output of timer becomes '1'
after a time period of 60 seconds. Now if the flame of burner is
become ON (within 10 seconds) the thermocouple is ready to
generate milli volt (mV). When the mV crosses some predefined
reference value, the comparator (C1) gives logic output '0'
through comparator (CP-1). All the three digital outputs are then
ANDed through AND circuit. Now as long as the flame is present
in the burner, the output of AND circuit is logic '0', as shown in
the Fig: 7. This is the final trip signal. As long as the trip signal
is logic '0' the motor will not operate and regulator remains in
ON position.
Case-3 (Regulator is ON, Oven is ON, Flame is OFF):- As long as
the oven switch is ON the output of comparator CP2 is logic '1'.
Now if at any time the flame is OFF by some means, then
temperature of thermocouple is falling down and after a few
seconds the milli volt(mV) generated by the thermocouple is
reduced. When the milli Volt is reduced to the reference value of
comparator (C1) it gives an output of logic '1'. Now at the same
time if the timer elapse its lcw time period and turn on to its
high output of logic '1', all the input of AND circuit are logic '1',
so its output is logic '1', which intern drive the motor control
circuit through limit switch(LS) and activate an alarm circuit.
The motor control circuit driver the 5V DC motor which intern
drive the motor-gear set and finally drives the CAM-1. The CAM-
1 is then driving the CAM-2, which is connected to the regulator
knob. After one revolution of CAM-1 the regulator is totally
stops the gas supply, as shown step by step in Fig: 8. The CAM-
1 will stops rotate when the lever (L1) operate the limit switch

(LS) and which intern cut the motor power supply, so the motor
becomes stop.
As long as the oven switch is in ON position and there is no
flame in the burner, after each 60 seconds the motor become
ON and simultaneously generate alarm, as shown in the Fig: 7.
When we turn off the oven switch to its OFF position then only
the whole circuit is reset.
Case-4 (Regulator is ON, Oven is OFF, LPG leaks by some
mean):- When the regulator is ON, there is a chance of LPG
leakage through the damage of pipe or through the base 'O'-ring
of the regulator. In such case the LPG gas sensor senses the
presence of LPG in the air. As the density of LPG increases the
the output voltage of LPG sensor is increases and when the
output voltage of LPG sensor become more than the
predetermined reference value the output of comparator (CP-4)
is logic '1'. As long as the LPG present in the sensor, the
comparator output is become logic '1', otherwise it gives a logic
'0'. The output of comparator (CP-4) directly operates the motor
control circuit. Which intern drives the motor and simultaneously
generate alarm. As long as the LPG present in the air, the
output signal of comparator CP-4 is logic '1' and also the motor
will operate with alarm until there is a fresh air present nearer
the LPG sensor.

Details of Drawings:
Fig:l-Describes the FRONT view of the Modern
Electromechanical Gas Safety Device (MEGSD) attached with the
LPG regulator.
Fig:2-Describes the TOP view of the Modern Electromechanical
Gas Safety Device (MEGSD).
Fig:3-Describes the FRONT view of the motor-gear
arrangements as used in Modern Electromechanical Gas Safety
Device (MEGSD).
Fig:4-Describes the flow chart of operation of the Modern
Electromechanical Gas Safety Device (MEGSD).
Fig:5-Describes the block diagram of Modern Electromechanical
Gas Safety Device (MEGSD) for single Oven operation.
Fig:6-Describes the block of Modern Electromechanical Gas
Safety Device (MEGSD) for double Oven operation.
Fig:7-Describes the timing diagram of operation of the Modern
Electromechanical Gas Safety Device (MEGSD).
Fig:8-Describes the steps of operation to stop the regulator by
the invented device, Modern Electromechanical Gas Safety
Device (MEGSD) attached with the LPG regulator.

I CLAIM
1. An Electromechanical Gas Safety Device that turns OFF
the LPG gas regulator with an alarm, if there is any
flame failure in the burner or there is any leakage of
LPG surrounds the regulator.
2. An Electromechanical Gas Safety Device as claimed in
claim 1, wherein the circuit arrangements of the
temperature switching mechanism, where the
Thermocouple is used as a temperature sensor and the
circuit that consist of Comparator-1, potential divider
for reference voltage.
3. An Electromechanical Gas Safety Device as claimed in
claim 1, wherein the circuit arrangements of the Oven
knob (switch) condition switching mechanism, where
the sensor used as a Magnetic Field sensor or Hall
Effect sensor along with button magnet and the circuit
that consist of Comparator-2, and a potential divider
for reference voltage, and a flexible cable of flexible
conduit.
4. An Electromechanical Gas Safety Device as claimed in
claim 1, wherein the circuit arrangements of the LPG
sensing switching mechanism which consists of LPG gas
sensor (semiconductor type) and the electronic circuit
that consist of Comparator-3, and a potential divider
for reference voltage.
5. An Electromechanical Gas Safety Device as claimed in
claim 1, wherein the circuit arrangements of the
electronic timer circuit that consists of Timer IC,
resistance and capacitors.

6. An Electromechanical Gas Safety Device as claimed in
claim 1, wherein the circuit arrangements of the signal
summing circuit that consists of three input AND gate.
7. An Electromechanical Gas Safety Device as claimed in
claim 1, wherein the circuit arrangements of the motor
driving circuit that consist of transistor, resistance,
Limit Switch.
8. An Electromechanical Gas Safety Device as claimed in
claim 1, wherein the circuit arrangements of the Alarm
circuit that consist of Musical IC, transistor, resistance
and speaker S.
9. An Electromechanical Gas Safety Device as claimed in
claim 1, wherein the motor-gear mechanism that
consist of a gear train of one worm gear and five spur
gear. The design of final driving shaft mechanism and
the air tight housing box.
10. An Electromechanical Gas Safety Device as claimed
in claim 1 wherein the mechanism of CAM-1 and CAM-
2, where the CAM-1 attached to the final driving shaft
of motor-gear set, and CAM-2 attached to the gas
regulator knob which is of removable press fit type.
11. An Electromechanical Gas Safety Device as claimed
in claim 1 wherein the clamp mechanism that holds the
entire invention (Air tight box) in above the gas
regulator.

ABSTRACT

The Modern Electromechanical Gas Safety Device (MEGSD) is a
new invented electromechanical device that attached
(additionally coupled) to existing gas regulator and can be of
removable type, and it will switch off the regulator and
simultaneously gives an alarm, if, 1) There is a flame failure in
the gas oven at its working condition, within maximum time
limit of 60 seconds or 2) There is a presence of LPG (by any
types of major/minor gas leakage) nearer the device.

ABSTRACT

The Modern Electromechanical Gas Safety Device (MEGSD) is a new invented electromechanical device that attached (additionally coupled) to existing gas regulator and can be of
removable type, and it will switch off the regulator and simultaneously gives an alarm, if, 1) There is a flame failure in the gas oven at its working condition, within maximum time
limit of 60 seconds or 2) There is a presence of LPG (by any types of major/minor gas leakage) nearer the device.