| 摘要 |
An apparatus 4 is designed to measure the calorific value and/or Wobbe index of a fuel gas supplied along pipe 2 and comprises an electronic control 22 which can operate outlet valves 32 and 36 and cause inlet valve 20 to be locked in a closed position or unlock it until the gas pressure in a chamber 6, of predetermined volume, reaches a predetermined pressure difference above the pipe pressure. Under control 22, pump 18 pumps a sample of fuel gas from pipe 2 into the chamber 6 whilst valves 32 and 36 are closed. On the pressure in chamber 6 attaining the predetermined difference, the valve 20 is held closed and the speed of sound in the gas, and/or the thermal conductivity, and/or specific heat capacity are measured. Then valve 32 is opened and the gas discharges back to pipe 2 through an orifice plate 34 and conduits 12, 16. This allows the measurement of the gas density. The viscosity of the gas is similarly measured using a capillary passage 38 and conduits 14, 16 and the calorific value etc. is derived. <IMAGE> |
