| 摘要 |
A method and apparatus (4) to measure the relative density of a gas, for example natural gas, in which the gas in supplied through an inlet (8) to chamber (6) and leaves through outlet (10). Using a control (16) and an ultra-sonic transducer emitter (12) and an ultra-sonic transducer receiver (14) the speed of sound in the gas corrected to standard conditions (sc) is calculated, then the control (16) operates to measure the relative density RD of the gas using the formula RD = a x SoSsc + b, where SoSsc is the speed of sound in the gas corrected to standard conditions, and a and b are constants. |
