This type of valve includes in itself the features of a through conduit service and of a standard gate valve with a parallel seating surfaces. The through conduit service implies the continuity of fluid flow conduit, excluding any dirt accumulation in the body cavity. The gate is in two halves (the so called “gate” and “segment”) with angled sliding surfaces, kept together by springs or by a lever system for larger dimensions.
Construction is available with single expanding or double expanding system. In the first case, the two halves of the gate are pushed against the seats in the valve closed position by having an internal stop acting on one of the two halves. In the second case the same expansion is also obtained in the valve open position.
During the gate travel from open to close, or close to open, the gate springs or the lever system prevent the gate from being in contact with the seats by “contracting” the two gate halves together. Usual construction is bolted bonnet. FLUITEK ORSENIGO VALVES can supply these valves in a variety of materials: carbon steel, low temperature carbon steel, austenitic stainless steel, duplex and super duplex stainless steel and nickel alloys.
Seating surfaces (seats, gate, sliding surfaces of the two gate halves) are provided with tungsten carbide coating, particularly for high pressure services.