Patent GB-1165634-A (GB)
Title: Improvements in Gas Calorimetry.
Inventor: MACCORMAC MICHAEL
IPC: G01N25/40
Filed: 1967-06-29
Abstract: 1,165,634. Gas calorimetry. GAS COUNCIL. June 19, 1968 [June 29, 1967], No.30025/67. Heading G1D. A method of measuring the calorific value of a fuel gas comprises supplying to a continuous flow calorimeter Fig. 4 metered amounts of a calorimeter heat exchange liquid e.g. mercury and of the fuel gas under predetermined conditions from a proportioning device Fig. 2 having a rotary member 27 with metering chambers 33 which are altenately filled with equal volumes of the heat-exchange liquid and the fuel gas, the liquid displacing the gas from each chamber and the subsequent outflow of liquid allowing more gas to flow in, so that the volume ratio of liquid to gas at the predetermined conditions is constant, the fuel gas being burnt at a burner 69 with air saturated with water vapour, the burnt gases passing along a flue 64 and into a heat exchanger 62, through which the heat exchange liquid flows, and measuring the temperature difference between the liquid leaving the heat exchanger 62, this temperature difference being a direct measure of the calorific value of the fuel gas. The whole apparatus is contained in a water bath at 0‹ C. The proportioning device comprises a body formed with three chambers 24, 25, 26, the middle one of which 26 contains the rotary member 27 driven by a motor (not shown). Mercury from the calorimeter is cooled by passage through a coil in the water bath and is fed to the upper chamber 24 through a pipe 16 a weir (not shown) maintaining the mercury level constant. The pipe 16 leads into a duct 17 communicating with the chamber 24, the incoming fuel gas being used to drive the mercury along the coil to the duct 17 where the separation occurs the gas passing to the lower chamber 25 through a pipe 18. The chamber 25 contains a float 43 with a ball valve 39, 40 to maintain the gas pressure in this chamber constant. The gas-from the chamber 25 is fed via a duct 50 to a chamber 53 where it enters and fills successive of the metering chambers 33 via a duct 54 as the member 27 rotates. The mercury leaving the chamber 33 is passed to the inlet of the calorimeter heat exchanger. The gas trapped in the chambers 33 leaves via a pipe 59 as the chambers register with a duct 55 leading to the chamber 24, and so fill with mercury. The head exchanger 62 is supported on insulating legs 61 in a Dewar flask 60, the burner 69 being fed with air through a pipe 65. The burner flue 64 loads to the heat exchanger 62, the gases leaving via an exhaust pipe 81, the incoming mercury from the proportioning device being supplied to a jacket 72 round the flue 64 after its passage through the heat exchanger 62 from an inlet pipe 57. Platinum resistance thermometers may be used to measure the temperature difference between the ingoing and outcoming mercury from the calorimeter. In the above described arrangement the gas pressure, and temperature are maintained constant and this gives the calorific value of the gas in relation to its volume. If desired calorific value per unit mass of gas can be measured if the float in the chamber 25 is replaced by a density balance arrangement to maintain the density of the gas metered by the proportioning device constant. If desired dibutyl phthalate may be used in place of mercury as the heat exchange liquid.