SUCTION THROTTLE VALVE FOR FEED TYPE SCREW COMPRESSOR

PURPOSE:To eliminate the leakage of oil or air to the air side by forming a sliding part into closed type by an unloader pistorn sliding at both supports and a valve sheet supporting one end of the supports. CONSTITUTION:When the capacity adjusting mechanism of a compressor is operated, an operation B chamber 17 becomes vacuum to move the unloader piston 22 of a suction throttle valve 1 in the compressor in the right direction. In addition, pressure in an operation A chamber 16 increases to positively move the unloader piston in the right direction, closing a valve sheet 21. And at the time of suspending the operation of the compressor, high-pressure air flows into he operation A chamber 16 to move the unloader piston 22 in the right direction, entirely closing the valve sheet 21. Thus, seals at the secondary side and the primary side (the air side) of the suction throttle valve 1 positively eliminate the leakage of oil or air without the assistance of a sliding part.