The Südmo Double Seal Valves are operated by compressed air, via a linear pneumatic actuator, that can be supplied with or without spring return. The at-rest position of the valve, although normally closed (down position), can also be provided in the normally open (up position), this is determined by the actuator mode being either Spring Extend (SE) or Spring Retract (SR) respectively as selected at time of order. The mode can also be easily changed on site by simply inverting actuator assembly. When air pressure is applied to the cylinder, two small pneumatic normally open (NO) poppet valves, a leak detecting and a CIP valve instantly close and the main valve plug moves through its entire stroke changing the valve from the closed to open position.

When the air is removed or vented from the cylinders the main valve closes, following which the two smaller valves open, thereby venting and draining the leakage chamber to atmosphere. With the main valve in the closed position the leakage chamber can be flushed with water or CIP to clean away product residues. Whilst the valve is in the closed position, one side of the valve can be CIP cleaned while product remains on the opposite side fully protected from possible contamination by the double seals and leakage chamber.