Plastic valve

A service valve comprising:

• a valve body having an upper chamber and a lower chamber;
• said upper chamber having a larger internal diameter than said lower chamber;
• said valve body having an open top end and an open bottom end;
• said lower chamber having an inlet opening and an outlet opening;
• a seat formed in said upper chamber between said open top end and said inlet and outlet openings in said lower chamber;
• a valve member having an external perimeter inserted into said valve body through said open bottom end and positioned against said seat;
• said valve member being molded of plastic material to form a unitary body including a plug portion and an actuator portion;
• said plug portion having a flow passage therethrough;
• said plug portion being rotatable in said seat between an open position where said flow passage is aligned with said inlet and outlet openings and a closed position where said flow passage is out of alignment with said inlet and outlet openings;
• said actuator portion extending outwardly from said plug portion through one of said chambers;
• an operating nut for engaging said actuator portion for imparting rotational motion to said plug portion;
• first and second seal means acting between said plug portion and said valve body for sealing against leakage from said inlet opening and said outlet opening;
• third seal means disposed between said valve body and second actuator portion for sealing against leakage into one of said chambers;
• locking means disposed on said valve member and adjacent said seat between said third seal means and one of said first and second seal means for locking said valve member within said valve body and said third seal means being insertable into place after insertion of said locking means to permit pressure testing of said valve for leaks between said valve member and said valve body during either of said open and close positions independently of said third seal means.