GB743655A - Installation for mixing aeriform media - Google Patents

Abstract

743,655. Mixing gases in flow. BLACKMAN, Ltd., K., and TAVERNER, E. E. Oct. 7, 1953 [Nov. 17, 1952], No. 28906/52. Class 86. In an installation for effecting the admixture of aeriform media, incorporating an inlet conduit for each medium, a common conduit for the admixed media leading to a gas consuming device, and a pressure-loaded governor controlling the pressure in each inlet conduit, there is provided a gas relay sensitive to the pressure of the admixed media at a control point to control the loading of the pressure-loaded governors. In the arrangement of Fig. 6, air and gas entering at points A and G pass through pressure regulated governors 1 and 2 which are interconnected by a pipe 14 whereby the govern- or 2 maintains the same pressure in a gas pipe 15 as prevails in an air pipe 10. From the pipes 10 and 15 the air and gas pass through restrictions 18 and 19 which are set for a predetermined mixture ratio to a mixing point 4 and the resulting mixture passes into a header 5 which supplies a number of burners 6. The pressure in the pipes 10 and 15 is regulated to prevent changes of pressure in the header 5 due to variation in demand by the burners 6, this regulation being effected by employing a gas relay in the form of a pressure governor 25 to control the pressure in the compartment 7 of the governor 1. In the governor 25 a compartment 32 above a diaphragm 34 is connected to the header 5, and a compartment 29 below the diaphragm is connected to a source of constant pressure, which may be derived from an external source (not shown) or from the air supply A through a pipe 26 in conjunction with a dead weight valve 27, a restriction 28 and an outlet pipe 30. The movement of the diaphragm 34 due to changes in pressure in the header 5 are applied to a piston valve 35 to mask or unmask a port 37 in an air line 38, 40 taken from the air supply A, the variation in pressure in this line being applied to the compartment 7 of the governor 1 by a pipe 39. The valve 31 in the air outlets 30 and 40 may be manually or thermostatically adjusted to determine the actual pressure conditions existing in the header 5. The restrictions 18, 19 are formed as ports in a piston 17 of a piston valve 3 which is controlled by a diaphragm 16 having compartments 20, 21 on opposite sides connected to the pipe 10 and header 5 respectively. The movements of the diaphragm 16 are such that the pressure drop across the ports 18, 19 remains constant at a value determined by the loading of the diaphragm 16 by the weight of the piston 17. As alternatives in Fig. 6 the compartment 13 of the governor 2 communicates directly with the compartment 7 of the governor 1 instead of with the compartment 12. Again, the pipe 40 may be replaced by a vent 41 from the compartment 7. A modification developed from Fig. 6 is provided with one air inlet and three gas inlets each fitted with a pressure-loaded governor. An arrangement according to Fig. 5, (not shown), is similar to Fig. 6 but the governors 1, 2 and 25 are connected in a different manner.