GB463549A - Improvements in or relating to automatic regulators - Google Patents

Abstract

463,549. Fluid-pressure servomotorcontrol systems. ELECTROFLO METERS CO., Ltd. (Dunglinson, B.) Sept. 25, 1935, No. 26552. [Class 135] A regulating-apparatus for controlling the condition, pressure, or flow of a fluid comprises a normally balanced lever 32 on a fixed pivot 34 which is adapted to be unbalanced by a change in the condition of the fluid to be controlled, for example, the flow of fluid in a conduit 12 which produces a change in the pressures on the two sides of a diaphragm 22. The resulting movement of the lever 32 controls the escape through a jet pipe 52 of a pressure fluid acting on a diaphragm 56 against a counter-weight 102. The diaphragm 56 acts as an amplifying device for the change in the physical condition of the controlled fluid and actuates a pilot valve 70 through a lever 84 to supply fluid pressure to one side or the other of a power piston 78 for effecting an adjustment of the regulator setting, in this case a valve 10 in the conduit 12. The lever 84 is also connected to the power piston 78 to provide a follow-up to restore the pilot valve 70 to its neutral position. Between the amplifying diaphragm 56 and the normally balanced lever 32 is a dashpot and spring device 86, 90, 92 to provide a restoring movement of the lever 32 in advance of the return to normal of the flow in conduit 12 to prevent hunting. This is effected by the tensioning of the spring 92, on movement of the dashpot 86 connected to the diaphragm 56, which tension gradually fades out by acting on the piston 90 of the dashpot as the condition of the fluid in conduit 12 returns to normal.