|Title of Invention||
AUTOMATIC GAS STOVE
|Abstract||In the present fast world, a person cooking in the kitchen has to do parallel work in addition to the cooking. Many times he/she forgets to switch off the gas stove at right time, which makes wastage of gas and some times, may cause series accident. The automatic gas stove provides a reliable solution for the above. This project switch off the L.P.G Gas stove automatically in two modes (1) Whistle Mode, (2) Timer Mode. In the whistle mode, after the required number of whistle is reached, the gas supply to the stove is switched off by a solenoid valve. The required number can be set by the user. In timer mode user have to set the off time of the stove. After the set time is reached, the stove is switched off automatically|
Objective: To automate the gas flow for the domestic gas stove.
This product is used to control the gas flow of a domestic gas stove. It stops the gas flow under two modes, namely 1. Whistle Mode and 2. Timer Mode. In the whistle mode, the whistle sound is converted into electrical signals using condenser microphone shown as  in figure 1. The converted electrical signal is amplified using an audio amplifier shown as  in figure 1. Only the whistle sound will be sensed, other than the whistle sound will be avoided. A Band Pass Filter (BPF) shown as  in figure 1 is introduced to allow the frequency from 7 kHz to 8 kHz. As the maximum whistle frequency of the pressure cookers is 8 kHz, the band pass filter allows only the whistle sound signal. The out of the BPF is fed to a decimal up counter shown as  in figure 1. The counter counts the number of whistle sounds. The output of the counter is compared using a comparator shown as  in figure 1 with the required number of whistles set by the user. The required number of whistles can be set using a set switch shown as  and a binary up counter shown as  in figure 1. When preset number and actual number of whistles become equal, the control signal from the comparator switches off the power supply of the solenoid valve through an amplifier shown as  in figure 1. The solenoid valve shown as  in figure 1 connected between L.P.G. cylinder and the L.P.G. stove gets closed and the gas flow is turned off. In timer mode, gas flow is kept on for the preset time. The timer shown as  in figure 1 is also used to set the preset time in timer mode.
This product switch off the L.P.Gas stove automatically in the following two modes:
1. Whistle Mode,
2. Timer Mode.
In the whistle mode, after the required number of whistle is reached, the gas flow to the stove is switched off by a solenoid valve. The required number of whistle can be set by the user. In timer mode user can set the ON time for the stove. After the set time, the stove is switched off automatically.
The MIC and Amplifier:
The microphone shown as  in figure 1, used in this product, can pick up any signal of audible range. The output potential of microphone is from 0 volt to 0.4 Volt. The pick up signal is fed to an audio amplifier shown as  in figure 1, to amplify the signal level to more than 0.2 Volt. The amplifier is designed using the transistor BC547.
The Band Pass Filter:
The band pass filter shown as  in figure 1, will allow only a certain band of frequencies. The band pass filter designed in this product is designed to allow 7 to 8 kHz frequency signals (8 kHz is the maximum frequency of pressure cooker whistle).
The Up Counter and the Comparator:
The output of the band pass filter is converted into pulses using a pulse generator. The pulses are fed into an up counter shown as  in figure 1. Counter counts the pulses coming from band pass filter. The BCD up counter IC 7490 is used here to count the whistles. The output of the up counter is compared with the preset number of whistles at every instant. User can set the preset number of whistles using a set switch shown as  in figure 1 and binary up counter shown as  in figure 1. When number of whistles and the preset numbers are equal, the output of the comparator shown as  in figure 1, goes high.
The Amplifier and the Solenoid Valve:
The output of the comparator is amplified using an amplifier shown as  in figure 1 and fed to a relay. The relay drives the solenoid valve shown as  in figure 1. The relay turn OFF the solenoid valve soon after receiving the comparator signal to stop the gas flow. If the output of the comparator goes low, the relay is switched OFF and the potential to the solenoid valve is switched ON. The solenoid valve is connected between the LPG cylinder and the stove.
In timer mode, the gas flow is controlled based on the time which is set by the user. The timer shown as  in figure 1, used in this project is a crystal controlled one which has the timing range of one second to 99 minutes. This time range can be achieved by dividing the crystal pulses. The time is set using the switch shown as  in figure 1.
The Mode Selection Switch:
The mode selection switch shown as  in figure 1 is used to select the any one of the mode from the two available modes. The gas flow between the stove and cylinder can be controlled automatically by using either whistle mode or timer mode.
As the reference sited above, the timer has been used to control the gas flow.
In the present invention, in addition to the timer, number of whistles is also used to control the gas flow, so that the operation can be done either in the timer mode or in the whistle mode. It is the novelty.
1. AUTOMATIC GAS STOVE comprising of a domestic gas stove which is put off when necessary based on whistle or timer mode, microphone to convert whistle signal to electrical signal, band pass filter allowing only whistle signal, amplifier, decimal up-counter to count the number of whistles, comparator to compare the number of whistles with the preset number, crystal timer to set the time in timer mode, relay to activate the solenoid valve to make the gas flow OFF automatically from the gas cylinder to the stove.
2. AUTOMATIC GAS STOVE as claimed in claim 1, wherein the gas flow in the stove is made to be off when necessary automatically.
3. AUTOMATIC GAS STOVE as claimed in claim 1, wherein the microphone used to convert the whistle signal into electrical signal.
4. AUTOMATIC GAS STOVE as claimed in claim 1, wherein the band pass filter allowing ONLY the whistle signal to the amplifier,
5. AUTOMATIC GAS STOVE as claimed in claim 1, wherein the amplifier used to amplify the electrical signal, converted from whistle signal.
6. AUTOMATIC GAS STOVE as claimed in claim 1, wherein the decimal up-counter counts the number of whistles in whistle mode.
7. AUTOMATIC GAS STOVE as claimed in claim 1, wherein comparator used to compare the number of whistles with the preset number and produce control signal to put off the gas flow.
8. AUTOMATIC GAS STOVE as claimed in claim 1, wherein timer used to set time for the gas flow in timer mode.
9. AUTOMATIC GAS STOVE as claimed in claim 1, wherein the
amplifier used to amply the control signal.
10.AUTOMATIC GAS STOVE as claimed in claim 1, wherein the relay put on oY off the power to the solenoid valve based on control signal input.
11.AUTOMATIC GAS STOVE as claimed in claim 1, wherein the solenoid valve used to stop the gas flow.
12.AUTOMATIC GAS STOVE substantially as herein described with reference to an accompanying drawing.
Dated this twenty first day of September 2004.
|Indian Patent Application Number||951/CHE/2004|
|PG Journal Number||27/2008|
|Date of Filing||21-Sep-2004|
|Name of Patentee||GOVINDASAMY MURUGESAN|
|PCT International Classification Number||F24C 3/12|
|PCT International Application Number||N/A|
|PCT International Filing date|