US Patent 7278441 Fluid controller

A fluid control device 1 has an upper space S1 formed between and defined by the upper surface of a piston 10 and the lower surface of top wall 8a of an upper casing 8, and a lower space S2 formed between and defined by the lower surface of the piston 10 and the upper surface of bottom wall 7a of a lower casing 7. A compression coil spring 11 for biasing the piston 10 is disposed in one of the upper space S1 and the lower space S2, and a compressed air admitting passage 15 communicates with the other space.