Classification of gate valve
1. According to the structure can be divided into the gate
1) parallel type valves with vertical sealing: two parallel, namely the centerline of the parallel seal gate valves. Parallel type gate usually adopt double disc structure.
In parallel type valves, to thrust wedge structure, most common in the two gate has double thrust wedge, the gate voltage and diameter (applicable to DN40-300mm) gate. There are two wedge between spring-loaded, spring can produce a wedge to be preloaded force, the seal.
2) wedge type valves with vertical sealing: in some perspective, namely the centerline of the two sealing into cuneiform gate.
The sealing Angle generally have 2 degrees 52 migrant, 3, 5 ° to 30 ° analysis, 8 °, 10 ° Angle, the size of the high temperature mainly depends on medium. Generally, the high temperature and the Angle should be taken to reduce temperature change occurs when the possibility of the wedge.
In wedge type valves, gate and single, double disc and elastic disc. Single sluice gate, wedge type of simple structure, reliable operation, but the Angle of sealing, processing and higher accuracy than difficulties, easy maintenance and scratches phenomena happen when the temperature changes, the possibility of the wedge. Double sluice gate structure clamp is complicated, in water and steam medium in pipelines use more. Its advantages are: to trim Angle accuracy, low temperature change easily cause wedge-shaped live phenomenon, sealing gasket, can add abrasion. But this kind of structure parts, easy in viscosity medium, seal binder. More important is, the long-term use of easy to produce rust, gate to fall off. The elastic disc wedge type gate, the structure characteristics of the gate is in a ring around the gate slot, with proper elasticity, it has sluice gate structure is simple, wedge type, and the advantages of using reliable can produce elastic deformation of trace for Angle sealing machining process, improve the technology of deviation, and has been used in great quantities.
Special purposes, such as the gate of long oil and gas pipeline with heavy-caliber gate valve and pipeline for cleaning the need and the single disc structure.
2 in the stem structures can be divided into the gate
1) rising stem valves: stem nut in bonnet or bracket, wedge, open and close with rotating stem nut to realize the valve stem. The structure of stem, the lubrication degree of open and close, so widely used.
2) dark stem valves: stem nut in body, direct contact with the medium. Wedge open and close, rotate the valve stem. This structure is the gate: constant, so total height of installation space is small, be applicable to the installation of space of large diameter or limitation of gate. This structure to open and close with open and close with indicator. This structure is: stem threads, and not only directly accepted lubrication, easy attaint.
