Asahi/America introduces 10- and 12-in. PVC wafer check valves. Valves are installed on the discharge side of pumps in aquariums, water attractions, water treatment facilities and municipalities to prevent back-flow flooding that could seriously damage pump systems. The valve’s body, disc and stopper assembly are machined from solid PVC plate stock, which conforms to ASTM D1784 Cell Classification 12454A.