GB482059A - Improvement in control systems - Google Patents

Abstract

482,059. Fluid-pressure servomotor-control systems. BAILEY METER CO. Nov. 27, 1936, No. 32515. Convention date, Dec. 18, 1935. [Class 135] A vapour generator of the drumless forced flow type in which a vapour separator is arranged between the generating and superheating portions of the fluid flow path utilizes the varying liquid level in the separator to control the operation in succession of a plurality of variables in the operation of the generator. The controlling arrangement shown in Fig. 1 is identical with that described in Specification 481,921 with the exception that the auxiliary valve actuated by varying liquid level in the separator controls a byepass valve 38 in the governor 'pump circuit and an emergency shut-off fuel valve 42 in addition to the air damper 15 and separator discharge valve 3. In a modification this auxiliary valve only controls the air damper 15 and a byepass valve across the feed water pump. A suitable control valve is shown in Fig. 3, and comprises a pair of spaced spherical bands 39 adapted to co-operate with narrow ports 40 whereby varying pressures are produced in the two outlets proportional to the movement of the valve. Where a different response is required at the two outlets one spherical band may be replaced by one 39<1> of double frusto-conical formation. The double valve may be replaced by two separate valves alternately actuated by a single member. Specification 425,507, [Group XII], is referred to.