Pressure control apparatus

A pressure control apparatus including:

• a pressure control apparatus body;
• a main valve and a diaphragm provided in said pressure control apparatus body;
• a directional control valve provided in connection with said pressure control apparatus body;
• a passage for communication between a supply port and an output port, said main valve being disposed in said passage;
• a diaphragm chamber formed by said diaphragm;
• a valve spring for urging said main valve in a direction in which it is closed;
• and
• a pressure regulating spring acting on said diaphragm to urge said main valve in a direction in which it opens, wherein force acting on said diaphragm changes in accordance with a switching operation of said directional control valve, and hence a pressure at said output port changes;
• said pressure control apparatus comprising:
• a central communicating passage formed in the passage for communication between said main valve and said output port:
• adapter connecting openings formed in two side surfaces, respectively, of said pressure control apparatus body, said adapter connecting openings being communicated with said central communicating passage through respective pressure communicating passages;
• an adapter connected to one of said adapter connecting openings;
• a pressure gauge provided in said adapter so that the pressure at said output port is transmitted to said pressure gauge through said central communicating passage and said pressure communicating passage;
• and
• a blanking plate assembly for closing the other of said adapter connecting openings.

A pressure control apparatus comprising:

• a pressure control apparatus body;
• a main valve and a diaphragm provided in said pressure control apparatus body;
• a directional control valve provided in connection with said pressure control apparatus body;
• a passage for communication between a supply port and an output port, said main valve being disposed in said passage;
• a diaphragm chamber formed by said diaphragm;
• a valve spring for urging said main valve in a direction in which it is closed;
• and
• a pressure regulating spring acting on said diaphragm to urge said main valve in a direction in which it opens, wherein force acting on said diaphragm changes in accordance with a switching operation of said directional control valve, and hence a pressure at said output port changes;
• wherein said diaphragm chamber and a small output port of said directional control valve are communicated with each other, and in accordance with the switching operation of said directional control valve, said diaphragm chamber is placed at a secondary pressure of said output port or at a primary pressure of said supply port, wherein when said diaphragm chamber is at the secondary pressure, the primary pressure flows to said output port after being reduced to a set pressure by said main valve, and when said diaphragm chamber is at the primary pressure, said main valve is fully closed;
• wherein said directional control valve has two small input ports, one of said small input ports being communicated with the supply port of said pressure control apparatus body, and the other of said small input ports being communicated with the output port of said pressure control apparatus body;
• an adapter provided on a side of said pressure control apparatus body, said directional control valve being connected to an outside of said adapter;
• wherein the small output port of said directional control valve is communicated with said diaphragm chamber through a first A output communicating passage formed in said adapter and a first B output communicating passage formed in said pressure control apparatus body, and one of said small input ports of said directional control valve is communicated with the supply port of said pressure control apparatus body through a third A input communicating passage formed in said adapter and a third B input communicating passage formed in said pressure control apparatus body, and wherein a second A input communicating passage is formed in said adapter, and a second B input communicating passage is formed in said pressure control apparatus body, said second A input communicating passage and said second B input communicating passage being communicated with each other through a communicating pipe, and the other of said small input ports of said directional control valve is communicated with the output port of said pressure control apparatus body through said second A input communicating passage, said communicating pipe and said second B input communicating passage.