Improvements in pneumatic controller

摘要

955,390. Fluid-pressure servomotors. ROBERTSHAW-FULTON CONTROLS CO. Sept. 1, 1960 [Sept. 3, 1959], No. 30169/60. Heading G3P. In a pneumatic controller a spring loaded pilot valve 46, Fig. 4, co-operates with a moving seat 41 connected to the free end of a bellows 10 to determine the pressure in a chamber 20 having an inlet 18 connected to a pressure source via a restriction 84 and to a control member e.g. a valve, via an output line 86 which is also connected to a pressure gauge 90. As described, a temperature detecting element 14, 72, 74, Fig. 1 moves an adjustable rod 76 which through an actuating arm 82 moves a lever 68 which abuts an extension 50 of the valve 46, the leverage being variable to set the proportional band.