Gate valve is a common common valve, the use of a wide range, mainly used in water conservancy, metallurgy and other industries, its extensive use of the performance has been recognized by the market. The following discussion on the structure of the valve, the use of common problems and preventive measures and other aspects of a general discussion.
Gate valve structure: gate valve is the use of gate and valve seat to control the opening and closing of the valve. Gate valve mainly body, seat, gate, stem, bonnet, stuffing box, packing gland, stem nut, hand wheel and other components. Rely on the relative position between the gate and the valve seat changes, you can change the channel size and can cut off the channel. In order to make the gate valve can be closed tightly, the gate and the valve seat mating surface after grinding.
According to the different shape of the gate valve structure, the gate valve can be divided into two categories: wedge and parallel.
Wedge gate valve wedge shape, the sealing surface and the channel center line into a tilt angle, the use of gate and the role of wedge between the valve seat to seal (closed). The wedge plate can be a single gate or a double gate.
The sealing surfaces of the parallel gate valves are parallel to each other and are perpendicular to the center line of the channel and are divided into two types: distraction mechanism and non-distraction mechanism. There is a double brake plate to open the mechanism, when the gate down, the two parallel wedge wedge on the slope of the two ramps in the valve seat, cut off the flow channel, when the gate rises open, Plate with the surface from the gate up to a certain height, the wedge is raised by the boss on the gate. The double brake plate without the opening mechanism, when the shutter along the two parallel seat surface slide into the valve seat, the use of fluid pressure on the valve gate pressure on the valve side of the valve body, sealed fluid.
According to the valve opening and closing when the valve movement is different, the gate valve is divided into two types of gate valve and dark bar gate valve. The stem and the gate of the pole gate valve are raised and lowered at the same time when they are opened or closed. When the stem valve is opened or closed, the stem is only rotated and can not see the lift of the stem and the valve plate is raised or lowered movement. The advantage of the pole gate valve is that the passage opening height can be judged by the height of the stem, but the height can be shortened. When facing the handwheel or handle, turn the handwheel or handle clockwise and the valve is closed.
Box valve use of the occasion and selection principles
1. flat gate valve
The use of flat gate valve occasions:
(1) oil, natural gas pipeline, with a diversion hole plate gate valve is also easy to clean the pipeline.
(2) Conveying lines and storage equipment for refined oil.
(3) oil and gas production facilities.
(4) Pipes with suspended particulate media.
(5) urban gas pipeline.
(6) water works.
Flat plate valve selection principle:
(1) oil, natural gas pipeline, use a single gate or double gate plate gate valve. If you want to clean the pipeline, use a single gate with a diversion hole of the pole plate gate valve.
(2) oil pipeline and storage equipment, the choice of non-diversion hole of the single gate or double gate plate gate valve.
(3) oil and gas development of the mouth device, the choice of the use of hollow rod seat with a diversion hole of the single gate or double gate plate gate valve.
(4) with suspended particles medium pipe, the choice of knife-shaped plate gate valve.
(5) urban gas pipeline, the use of single-gate or double-gate soft seal Mingzhu plate gate valve.
(6) water works, choose a single gate or double gate without diversion hole Ming bar plate gate valve.