Title:
DIFFERENTIAL PRESSURE CONTROLLER
Document Type and Number:
Japanese Patent JPS5850015
Kind Code:
A
Abstract:
PURPOSE:To hold accurately a constant pressure, by separating a pressure chamber and a residual pressure chamber from each other through a diaphragm and detecting the position of the diaphragm to generate a control signal and providing a differential pressure controller which applies this control signal to a reducing valve. CONSTITUTION:Air is sent from a compressor into a low-pressure casting furnace 12 through a pressure controlling valve 14 and a solenoid switching valve 16a, and a pressure is held for a certain time to perform the low-pressure casting. Next, the valve 16a is closed, and a solenoid switching valve 16a is opened, and air for control of residual pressure is sent into the furnace. Simultaneously, a reducing valve 34 is opened to lower the pressure in the furnace. This pressure lowering is transmitted to a pressure chamber 24 of a differential pressure controller 20 through a pressure piping. Since air controlled to a required residual pressure is sent to a differential pressure chamber 26 from the pressure piping connected just after a residual pressure controlling valve 18, the differential pressure is detected by a diaphragm 22 of the controller 20, and a proximate switch is operated in the state where the differential pressure chamber 26 is completely balanced between the dropping air pressure in the pressure chamber and the required residual pressure in the residual pressure chamber 26, and the valve 34 is closed in this state.
Inventors:
TAKIGUCHI ETSUO
Application Number:
JP14814181A
Publication Date:
March 24, 1983
Filing Date:
September 18, 1981
Export Citation:
Assignee:
NISSHIN KOGYO KK
International Classes:
G05D16/00; B22D18/04; B22D18/08; (IPC1-7): B22D18/04; G05D16/00
Attorney, Agent or Firm:
Takao Watanuki