Piston Valve is a seatless and glandless valve. There is no direct contact of the piston surface and the fluid. Therefore, there is no corrosion risk for the sealing surfaces. Only the bottom surface of the piston gets into contact with the fluid. This part is not related to the sealing performance. Sealing system in the piston valve is enabled by a stainless steel piston and a couple of special elastic rings which surround the piston tightly.
The upper valve ring provides the stem seal, while the lower valve ring seals the passage. The large sealing surface on the piston and rings provides an optimal seal. When closing the valve, the piston pushes and wipes away any impurities, which might be present in the fluid, ahead of itself. Therefore media with fibrous or contaminated constituents are reliably sealed.