Patent ID: 8720850

Claim:
A suck back system, comprising: an integral-type suck back valve, the integral-type suck back valve comprising: an on/off valve, operated bye first pneumatic actuator so as to close and open a fluid channel; and a suck back diaphragm provided at a downstream side in the fluid channel relative to the on/off valve, for performing a suck back function by being deformed after the on/off valve is operated to close the fluid channel; a protective on/off valve provided at an adjacent upstream side in the fluid channel relative to the on/off valve of the integral-type suck back valve, the protective on/off valve configured to perform a fully closing operation to fully close the fluid channel at the adjacent upstream side in the fluid channel relative to the on/off valve by a second pneumatic actuator; and an opening and closing control unit that controls the protective on/off valve to complete the fully closing operation of the protective on/off valve earlier than full closing of the on/off valve of the integral-type suck back valve when the on/off valve of the integral-type suck back valve is operated to close the fluid channel.