Patent GB-156502-A (GB)
Title: Improvements in fluid proportioning apparatus
IPC: G05D11/00
Filed: 1921-01-05
Abstract: 156,502. Radiometer Corporation, (Assignees of Lundgaard, I.), April 21, 1919, [Convention date]. Valves controlled by pilot or relay valves.- Relates to fluid-proportioning apparatus for controlling the rate of flow in one conduit according to the rate of flow in another conduit so as to maintain the proportionate rates of flow in the two conduits constant, and comprises means for regulating the rate of flow through one of the conduits, independently - actuated operating means for operating said regulating means, and means for controlling the operating means actuated by the resultant force of a pressure difference dependent on the rate of flow in one conduit opposed to a pressure difference dependent on the rate of flow in the other conduit. The apparatus is applicable to carburettors, or air and gas mixers for gas furnaces &c. and is shown as applied to a device for securing a constant proportional mixture of gas and air. The gas and air conduits 1, 2, Figs. 1 and 7, are provided with reduced throats 3, 4 the areas of which are adjustable by means of conical members 10 carried by bent rods 11 which have racks gearing with pinions on shafts 13 actuated by means of finger-pieces 14. A valve 17 in the air conduit is connected to a diaphragm 19 in a chamber 16 carried by a housing 15 mounted between the conduits. The diaphragm 19 is connected by a bellows 20 of leather &c. to one of the inner walls of the chamber 16. The housing 15, Figs. 3 and 4, is divided into two chambers 27, 28 by a partition 23 which is divided at its upper end to form two walls 24, 25 carrying a shaft 26. Fluidpressure diaphragms 31, 32 in the chambers 27, 28 are connected by bellows 33, 34 with the opposite inner walls of the chambers, and are carried on frame members 37, 37<1>, 37" supported on the shaft 26. Pipes 35, 36 opening into the bellows 33, 34 lead to unrestricted portions of the conduits 1, 2; and pipes 29, 30 place the chambers 27, 28 in communication with the throats 3, 4 of the conduits. The member 37 is pivotally connected with a slide-valve 38, Fig. 6, operating in a casing 39 carried by the housing 15. The casing 39 has a longitudinal passage 40 open to the atmosphere at the outer end and a number of lateral openings 41, 42, 43, 44 leading therefrom. The opening 44 leads directly to the atmosphere and the opening 43 is connected by a pipe 47 to one of the conduits 1, 2. Pipes 45, 46 lead from the openings 41, 42 to the chamber 16, the pipes 46 opening within and the pipe 45 to the outside of the bellows 20. The valve 38 has three enlarged portions 38<1> so arranged that one of the openings 41 or 42 is always in communication with the atmosphere through the opening 40 or 44, while the other is in communication with the conduit 2 through the opening 43 and pipe 47. In operation, the valve 38 connects either of the pipes 45 or 46 with the conduit 2 and opens the other pipe to the atmosphere through the valve casing. The fluid pressure differentials in the conduits 1, 2 act in opposite directions to move the diaphragms 31, 32 and the frame connected therewith to actuate the valve 38, and actuation of this valve serves to connect one side of the diaphragm 19 with the fluid pressure from the conduit 2 and the other side with the atmosphere through one of the openings 40, 44 in the casing 39, whereupon the valve 17 is operated to close more or less the conduit 2.