Uni-directional valve seats or SPE seats (also known as as Self Relieving seats) offer sealing If your upstream stress is larger compared to cavity force (see Figure one) but will leak If your cavity force is greater than the upstream tension (see Determine 2). While in the closed position of http://valves-and-fittings03579.full-design.com/The-best-Side-of-dbb-valve-29327612