Plast-O-Matic Valves Inc. has introduced Series BSR, a balanced, air operated shut-off valve for ultra pure and corrosive applications. These compact valves are designed for liquid service ranging from full vacuum to pressures up to 150 psi. The “balanced” aspect means that the valve outlet pressure, commonly known as back-pressure, can be as high as the inlet pressure without affecting performance. Typical diaphragm style shut-off valves require a pressure differential to close properly. Series BSR uses compressed air for operation, and will automatically close “fail safe” in the event of air pressure loss.