Check valve

A check valve for use in a semiconductor manufacturing process, said check valve comprising:

• a check valve main body made of a synthetic resin, having a channel passing therethrough;
• a synthetic resin-made valve disc provided to said channel somewhere therethrough, for opening and closing said channel;
• and
• a synthetic resin-made spring for pressing said valve disc in a valve-closing direction, in such a configuration that when a valve-opening directional fluid pressure in excess of a pressing force of said spring is applied to said valve disc, said valve disc moves in a valve-opening direction with said spring being compressed, to open said channel;
• wherein said spring is formed coaxially to and integrally with said valve disc, said valve disc having a rear section defining a portion of a conical surface, said conical surface having a diameter which progressively decreases as said conical surface extends rearwardly toward said spring, said valve disc including a plurality of evenly spaced guide plates, said guide plates integrally formed and extending radially outwardly and rearwardly from said conical surface, said guide plates each having a rearward end and said spring being connected to said guide plates at radially inner portions of said rearward ends;
• and
• valve disc movement amount regulating means for regulating an amount of movement of said valve disc in the valve-opening direction in order to prevent full compression from occurring onto said spring.