Double shut-off valves
Where 100% leaktightness, even to TRD, is demanded then double shut-off butterflies are deployed. Two butterflies or one butterfly with double sealing form an air seal chamber in the closed state into which a barrier medium, e.g. air, is blown. Our technicians calculate the required barrier air volume and pressure such that a 100% leak-tightness is guaranteed for all operational states. With options such as differential pressure measurement for monitoring the leak-tightness, barrier air heating to prevent falling below the dewpoint and a swing-type non-return valve in the barrier air line to protect the blower from the medium, we supply complete and fully functional units.
Function | Shut-off, 100% medium-tight with sealing air |
Cross section | in circular or rectangular execution |
Design | as flange valve or weld-end valve |
Flange connection | to DIN / BS / ANSI / customer specification |
Number of leafs | single leaf, multiple leaf |
Medium | gaseous, pressure range to 10 bar, temperature range -50 to +1200°C |
Explosion protection | optional |
Shaft seal | gland packing, also Clean Air Guidelines conformant /O-ring |
Leaf seal | without (sweeping) / metallic striking / soft seal, chambered |
Insulation | without / internally lined / internally clad with fibre insulation / prepared for on-site external insulation |
Materials | steel / stainless steel |
Actuation | electric / pneumatic / hydraulic / hand lever / also with emergency actuation in the case of power failure |