It is designed according to BS-1868, API-6D and ASME B16.34 standards.
This valve is unidirectional and the closure member is disc-shaped, assuring the seal tightness by mean of a uniform seating stress all around the seating circumference, thanks to the pressure of the fluid in return.
The valve can be full opening disc design (API-6D), allowing the pass of all kind of cleaning pigs through it, or reduced opening, with a stop in the body, in order to avoid the trapping of the disc, which can produce non closing of it. The standard manufacturing program is according to internal shaft design, reducing a leak point in the valve, but we also manufacture extemal shaft when it is required to fit a dashpot (big sizes or non-slamming applications) or a counterweight if vertical pipe service is specified. Seat rings are screwed to the body, welded or not depending on size, and they can be machined in the body for valves in austenitic material, it means, integral seat. Both types are renewable, fulfilling all the international applicable standards.