GB490607A - Improvements in or relating to the regulation of the flow of fluids - Google Patents

Abstract

490,607. Fluid-pressure servomotor-control systems. ASKANIA-WERKE AKT.- GES. VORM. CENTRALWERKSTATT DESSAU UND C. BAMBERG-FRIEDENAU. Feb. 17, 1937, No. 4818. Convention date, Feb. 17, 1936. [Classes 69 (i) and 135] In control apparatus for maintaining the fluid flows in a number of separate conduits in a desired relation, a variable throttle device such as 13 or 14 in each conduit is regulated so as to maintain the pressure difference between its opposite sides constant and the variation in the position of each throttle device is utilized to control the fluid flow in one or more of the conduits so as to maintain the desired relation. In the apparatus shown in Fig. 1 for mixing two separate fluids at substantially constant pressures in pipes 10, 11 in a mixing conduit 12, the variable orifice plates 13, 14 are operated by servomotors 17 controlled by pivoted jet pipes 22 under the control of diaphragms 21 subject on their opposite sides to the pressures on the two sides of the orifice plates by means of pipes 19, 20. The servomotors 17 also operate wedge cams 18 which through bell-crank levers 26 and springs 27 act in opposition on a third relay device of the jet pipe type which controls a butterfly or other valve 34 in one of the conduits. The relative effect of the two impulses may be adjusted by a slidable member 29 contacting the jet pipe 25 and a counter lever 28. Any discrepancies in the proportionality of the impulses to the fluid flows may be remedied by making the cams 18 adjustable or by adjusting the compression springs. Apparatus is also shown in which the flow in a conduit is controlled so that it bears a desired ratio to the sum of the fluid flows in two other conduits. Each conduit has a variable orifice plate controlled by a relay of the jet pipe type as in Fig. 1, and the impulse from the relay in the controlled conduit is balanced against those from the relays of the other two conduits which act through a floating lever. The resultant impulse operates a jet pipe relay controlling a butterfly valve as in Fig. 1. In Fig. 3, the conduits 60, 61 each have a flow meter comprising a piston valve 62 or 63 which rises in proportion to the flow so that the pressure difference between its opposite ends remains substantially constant. Armatures 64, 65 connected to the respective piston valves, when moved, disturb the balance between pairs of coils 66, 79 and 67, 70 supplied from leads 68, 69 causing sympathetic movements of armatures 74, 80 which act in opposition on a jet pipe relay controlling a valve 82 in one of the conduits. U.S.A. Specifications 1,333,986 and 1,558,529 are referred to.