STAINLESS STEEL CHECK VALVES
Combining the best features of durability and positive sealing, these unique valves are constructed throughout of 316 Series Stainless Steel for the high corrosion resistance essen- tial in the chemical, processing and power generating industries.
PTFE seat seal for positive bubble-tight sealing (with gas) from cryogenic to 375° F (190°C) temperatures. Seals also available for radioactive environments, or up to 500°F steam. Can be furnished without soft seat for higher temperature steam service.
Sizes 1/4" through 1" use a ball, and for reduced inertia, the larger sizes (1-1/4", 1-1/2" and 2") use a poppet. Cracking pressure is 1-4 psi.
Larger valves can be furnished for flange mounting to customer specifications on special quantity orders. Consult factory.
Semi-soft means the check ball or poppet initially seats on the PTFE, but after the PTFE deflects a slight amount, the ball or poppet comes to rest against the metal seat so the PTFE does not have to absorb the full load of the high pressure.
Internal passages have flow capacity equal to or greater than double extra heavy pipe of the same size that would be required to carry the rated pressure (see CV factor in chart below).
Typical of good Haskel design is the removal of springs. from the flow path. The larger spring is outside the flow and simply provides a preload for the disk. The smaller spring, inside the cage, actuates the ball or poppet but the flow, which is routed through the cage windows, misses the spring entirely. This is why the valves will stand extremely high shock loads and have been tested at rapid high shock up to 2 million cycles without failure.
