Survey Paper on LPG Gas Detector With Auto Cut Off Regulator

Abstract

Liquefied Petroleum Gas (LPG) is widely used in domestic kitchens, restaurants, and small industries, but accidental gas leakage can cause fire, explosion, or asphyxiation. To prevent such hazards, an LPG Gas Detector with Auto Cut-off Regulator using a DC Servo Motor is proposed. The system continuously monitors the surrounding air with a semiconductor gas sensor (such as MQ-6) that is sensitive to propane and butane. Sensor signals are processed by a microcontroller which compares the measured concentration to a preset safety threshold.
When the gas level exceeds this threshold, the controller triggers two immediate safety actions:
1. Alarm Activation: A buzzer and indicator LEDs warn occupants to evacuate or ventilate the area.
2. Automatic Gas Shut-off: A DC servo motor rotates the regulator valve to the OFF position or drives a mechanical cut-off attachment, instantly stopping the gas supply.
The DC servo motor is chosen for its accurate angular control, fast response, and low power requirement, ensuring reliable closure of the gas valve within seconds of leak detection. To enhance dependability, the design can include a rechargeable battery backup for power outages and a manual override for emergency operation.

This integrated approach—early leak detection combined with automatic mechanical isolation—significantly reduces the time window for ignition, offering a cost-effective, user-friendly, and safer alternative to alarm-only systems. It is suitable for retrofit installation on standard domestic LPG cylinders and can be adapted for small commercial kitchens, thereby improving overall safety and protecting lives and property in LPG-dependent environments.