New shut-off butterfly valves for liquefied gas transport

As a complement to its extensive range of butterfly valves for handling liquefied gas, KSB Aktiengesellschaft, Frankenthal, Germany will be presenting the new TRIODIS valve series at this year’s ACHEMA. The maintenance-free triple-offset butterfly valves are designed for handling fluids with temperatures ranging from minus 250 to plus 200 degrees Celsius, depending on their properties, and operating pressures of up to 100 bar. Thanks to their special design, the closing torque is lower than that of double-offset disc valve types, which makes them suitable for use with smaller actuators. With their triple-offset design and tapered sealing surfaces, the valves ensure tight closure even at very high differential pressures. Sealing can be effected by means of HELICOFLEX® seat rings which are known for their excellent performance in cryogenic applications the world over.

The valves provide bidirectional shut-off. The butterfly valves do not require a travel stop for the closed position, because their metal seat forms a natural stop. This protects the valve seat should the actuator operate the valve in the wrong direction. The valve stem is a single-piece design supported by generously dimensioned plain bearings. Tight shut-off is ensured even after numerous actuating cycles. An additional anti-blow out device prevents the stem from being blown out of the body in the event of a failure. TRIODIS butterfly valves are available with diameters ranging from 200 to 1200 mm. The stainless steel bodies can be supplied either with flanges or with butt weld ends. The series includes a special butt-weld side-entry version. The butt weld end serves to weld the valve into the piping. For maintenance the valve trim can be pulled out of the body without having to remove the entire valve. This is a major advantage, especially when space is limited. The new type series will continue to provide tight shut-off even in the event of a fire.

It has successfully passed the Fire Safe Tests to API (American Petroleum Institute) and BS (British Standard). These tests were performed at the research centre in Gradignan, France, on a KSB test stand which was specially built for this purpose. The actuator flanges and stem ends will accommodate manual, pneumatic, hydraulic and electric actuators of any make. Sixty percent of all gas tankers worldwide as well as many loading and processing terminals are currently equipped with KSB’s AMRI valves.