Patent ID: 7686588

Claim:
A liquid chemical supply system, comprising: a liquid chemical pump comprising: a pump chamber; an operation chamber; and a flexible membrane that separates the pump chamber and operation chamber, the liquid chemical pump performing intake and discharge of a liquid chemical by changing the volume of the pump chamber in accordance with a change in pressure inside the operation chamber; the liquid chemical supply system further comprising: an operation gas supply device; and a plurality of pressure detectors having different pressure detection ranges that detect a pressure of an operation gas supplied by the operation gas supply device; and a controller that performs pressure feedback control by selectively employing a detection result of one of the plurality of pressure detectors in accordance with a pressure setting value of the operation gas, the pressure setting value being newly set before each operation of the liquid chemical supply system; a plurality of on-off switching valves; and an operation gas pathway that links the operation chamber and the operation gas supply device, wherein each of the pressure detectors are connected via a corresponding one of the on-off switching valves to the operation gas pathway, each of the on-off switching valves is capable of being opened in accordance with the pressure setting value, and the pressure detectors are placed in a pressure detection state.