Air and water supply valve structure in endoscope

摘要

A piston of an air and water supply valve in an endoscope comprises: a base cylinder; a water supply switching piston; and an air supply switching piston, which is inserted in the water supply switching piston. An air supply button functioning as a check valve is attached to the top end of the air supply switching piston, and air is supplied by slightly pressing the air supply button and water is supplied by deeply pressing the air supply button. If liquid flows back, the air supply button functions as the check valve to prevent the backflow from flowing into the base cylinder from the air supply switching piston.