It is also a type of check valve that operates because of the difference between upstream & downstream pressures. When the inlet pressure is high then the disc lifts up and the valve allows the fluid to flow to the outlet side. If the downstream or gravity pressure if higher than inlet pressure the disc gets back to its seat. This way reverse flow is blocked. For the smooth process it is important to have durable working disc and this is what we offer. We examine the raw material to be used in our product’s exporting. This results in durable quality production.