Features of the Use Structure of Flat Gate Valve

Jun. 15, 2020

Flat Gate Valve is a sliding valve whose closing part is a parallel gate. The closing member may be a single shutter or a double shutter with a spreading mechanism therebetween.

The pressing force of the gate to the valve seat is controlled by the medium pressure acting on the floating gate or floating valve seat. If it is a double gate plate gate valve, the expansion mechanism seen by the two gates can supplement this pressing force.

One. Features of Flat Gate Valve

1. The valve seat is sealed with an O-ring seal and a floating valve seat structure that applies a preload so that the inlet and outlet of the flat gate valve are sealed in both directions; and the opening and closing torque of the structure is only 1/2 of the ordinary valve, which can easily open, Close valve

2. When fully open, the channel is smooth and straight, the flow resistance coefficient is extremely small, and there is no pressure loss. The pipeline can be cleaned through the hairball;

3. A packing structure with self-sealing capability is used, which does not require frequent adjustment. It is extremely easy to open and close and has the reliable sealing performance. A supplementary sealing grease injection structure is provided at the packing box. The sealing performance is absolutely reliable and truly reaches zero leakage; The most prone to leakage at the valve packing;

4. When the flat gate valve is closed, it can automatically remove the high pressure in the inner cavity to ensure safe use;

5. Fully enclosed structure, good protection performance, can adapt to all-weather requirements.

Two. Applicable occasions of flat gate valve

1. (Class150~900/PN1.0~16.0MPa, working temperature -29~121℃) petroleum and natural gas pipelines. Flat gate valves with diversion holes are also convenient for cleaning pipelines.

2. Transportation pipelines and storage equipment for refined oil.

3. Wellhead devices for oil and natural gas extraction, that is valves for Christmas trees.

4. Pipes with medium containing suspended particles.

5. City gas transmission pipeline.

6. Waterworks.

Flat Gate Valve

Flat Gate Valve

Three, the advantages of a flat gate valve

The flow resistance is small, and the flow resistance of the non-shrinkage is similar to that of the short tube. The flat gate valve with diversion holes is installed on the pipeline and can also be cleaned directly with a pig. Because the gate slides on the two valve seat surfaces, the flat gate valve fluid can be applied to the medium with suspended particles, and the sealing surface of the flat gate valve is actually automatically positioned. The sealing surface of the valve seat will not be damaged by the thermal deformation of the valve body. And even if the valve is closed in a cold state, the thermal extension of the valve stem will not overload the sealing surface. At the same time, when the valve is closed, the flat gate valve without diversion holes does not require the closing position of the gate plate to have higher precision, so the electric flat valve can use the stroke to control the opening and closing position.

Four. the disadvantages of flat gate valve

When the medium pressure is low, the sealing force of the metal sealing surface is insufficient to achieve a satisfactory seal. On the contrary, when the medium pressure is high, if the sealing surface is not lubricated by the system medium or external media, frequent opening and closing may cause excessive wear on the sealing surface. Another shortcoming is that the circular gate moving laterally on the circular flow path is only sensitive to flow control when it is at 50% of the valve's closed position. Moreover, when the shutter breaks the high-speed and high-density medium flow, it will produce violent vibration. If the valve seat is made into a V-shaped port and is closely guided with the gate, it can also be used as a throttle.

Five. Selection principles for flat gate valves

1. For the pipelines for oil and natural gas, flat gate valves with single or double gates are used. If you need to clean the pipeline, choose a single gate or double gate with a straight rod flat gate valve with diversion holes.

2. For the transportation pipeline and storage equipment of refined oil, use a single gate or double gate flat gate valve without diversion hole.

3. For oil and natural gas wellhead devices, single gate or double gate flat gate valves with diversion holes in dark rod floating valve seats are selected, most of which are API16A standards, and the pressure levels are API2000, API3000, API5000, API10000, API15000, API20000.

4. For pipelines with suspended particulate media, use knife-type flat gate valves.

5. For city gas transmission pipelines, use a single gate or double gate soft-sealing exposed rod flat gate valve.

6. For city running water project, choose single gate or double gates without diversion holes and open rod flat gate valve

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