1. Features of flat gate valve

1. The valve seat adopts an O-ring seal and a floating seat structure that applies pre-tightening force to seal the inlet and outlet of the flat gate valve in both directions; and the opening and closing torque of this structure is only 1/2 of that of ordinary valves, which can achieve easy opening and closing. Close the valve;

2. When fully opened, the channel is smooth and straight, the flow resistance coefficient is very small, and there is no pressure loss, and the pipeline can be cleaned with a hair ball;

3. The packing structure with self-sealing capability is adopted, without frequent adjustment, the opening and closing are extremely light, and the sealing performance is reliable. There is an auxiliary sealing grease injection structure at the stuffing box, and the sealing performance is absolutely reliable, and it truly achieves zero leakage; it solves the general purpose The most prone to leakage at the valve packing;

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

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

2. Applicable occasions of flat gate valve

1. (Class150~900/PN1.0~16.0MPa, working temperature -29~121℃) oil and natural gas transmission pipeline. The flat gate valve with diversion hole is also easy to clean the pipeline.

2. Transportation pipelines and storage equipment for refined oil.

3. Oil and natural gas extraction wellhead devices, that is, valves for Christmas trees.

4. Pipes with medium with suspended particles.

5. City gas transmission pipeline.

6. Tap water works.

Three, the advantages of flat gate valve

The flow resistance is small, and its flow resistance without shrinking is similar to that of a short tube. The flat gate valve with diversion hole can be directly used for pigging when installed on the pipeline. Since 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. Moreover, even if the valve is closed in a cold state, the thermal elongation 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 hole does not require the closing position of the gate to have a higher accuracy, so the electric flat valve can use the stroke to control the opening and closing position.

Fourth, the shortcomings of the flat gate valve

When the medium pressure is low, the sealing force of the metal sealing surface is not enough to achieve a satisfactory seal. On the contrary, when the medium pressure is high, if the sealing surface is not lubricated by system medium or external medium, frequent opening and closing may cause excessive wear of the sealing surface. Another disadvantage is that the circular gate that moves laterally on the circular flow channel is only sensitive to flow control when it is at 50% of the valve closed position. Moreover, the gate will vibrate violently when the high-speed and high-density media flow is interrupted. If the valve seat is made into a V-shaped port and guided tightly with the gate, it can also be used as a throttle.

Five, the principle of selection of flat gate valve

1. For oil and natural gas pipelines, use flat gate valves with single or double gates. If you need to clean the pipeline, use single or double gate open-rod flat gate valve with diversion holes.

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

3. For oil and natural gas mining wellhead devices, single-gate or double-gate flat gate valves with dark rod floating valve seats and diversion holes are used, 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-shaped plate gate valves.

5. For the city gas pipeline, use single gate or double gate soft-seal open-rod flat gate valve.

6. For urban tap water projects, use single or double gate open-rod flat gate valves without diversion holes.