VB-300 Trunnion Mounted Ball Valve

Product detail

Once a ball valve gets past about DN150 or Class 300, a floating ball puts too much load on the downstream seat and the operating torque climbs with line pressure. The VB-300 carries the ball on upper and lower trunnions instead, so the pressure load goes into the bearings and the seats only have to seal. Torque stays roughly flat across the pressure range, which is what makes a compact actuator possible.

Seats

Spring energised seat rings seal at low differential pressure as well as at full line pressure, which matters during commissioning and hydrotest when there is not enough pressure to energise a plain seat. Soft seats for clean service, metal seated with a hardfaced ball where the medium carries sand or catalyst fines.

Double block and bleed

Both seats seal against the body cavity, so with the valve closed the cavity can be vented through the body drain and the seal on each side proved independently. That is the reason this valve is specified for isolation ahead of maintenance work rather than a cheaper single seated design.

Fire safe and antistatic

Secondary metal-to-metal seating behind the soft seat, a graphite body gasket, and a stem spring contact to ground the ball and stem through the body. The design is built to the fire test and antistatic requirements described in API 6D and API 607; the test report for a given order is quoted separately.