Calcutta scientists develop alarm for LPG leak

So if a cylinder is left open allowing the gas to leak, the alarm warns the user minutes before it is too late to act, says Dr H S Maiti, head of the research team of Central Glass and Ceramic Research Institute (CGCRI), that has developed the handy sensor.

Compared to costly electrochemical sensors that have to be refilled after every few days to be able to detect a leak, the cheap zinc oxide-based thin film gas sensor head has an indefinite shelf life, providing for much longer use, Maiti says.

"The sensor is the first of its kind developed in the country and is expected to cost around one third of imported sensorspriced at above Rs 800," he says.

The premier CSIR institute is currently conducting final field trials of the sensor and expects to manufacture it in a large scale early next year.

Explaining the mechanism of the sensor, Maiti said the zinc oxide film being semi-conductive in nature, dissociates Liquified Petroleum Gas (a mixture of reducing gases octane and butane) after a permissible limit.

"This, in turn, results in a conductivity drop in the film which is converted into an electric signal and subsequently an audible one," he observes.

After correcting initial operational errors like long-term degradation in sensitivity, the sensors are being modified to meet required standards.

The team from the electroceramics unit of the institute comprising A K Maiti, P Mitra, A K Halder and Maiti, are currently thinking on the lines of making sensors for carbon monoxide and methane to be used in coal mines.