Natural gas supply systems for most developed countries are growing into a highly complex distribution system where fuel gas is introduced into the system at different points from various domestic gas fields, or from connections to international pipe lines and liquid gas supply terminals. The Gas Properties Transmitter (GPT) from Rapidflame, incorporates a solid state fuel gas quality sensor system which compares physical properties of the fuel gas sample against expected "programmed" properties and gives an output of changes for control or monitoring purposes. The device is very accurate, can be mounted in flammable areas and is normally used in gas billing applications where gas calorific value is monitored next to the meter and users are billed for energy used in kWhrs rather than gas volume used.
