Flat gate valve is a sliding valve with parallel gate. The closing parts may be single gate or double gate with a spreader. Gate to seat pressure is controlled by the medium pressure acting on the floating gate or floating seat. If it is a double gate plate gate valve, the spreader between the two gates can supplement this pressure.

Plate gate valves can be divided into manual plate gate valves, pneumatic plate gate valves and electric plate gate valves. It can be divided into flat gate valve with guide hole, flat gate valve without guide hole, oil field flat gate valve, pipeline flat gate valve and gas flat gate valve.

Applicable occasions
1. (Class150 ~ 900 / PN1.0 ~ 16.0 MPa, working temperature - 29 ~ 121 ℃) of oil, natural gas pipeline. Flat gate valves with orifices are also easy to clean lines.
2. Transportation pipeline and storage equipment for refined oil products.
3. Oil and gas production well head device, i.e. tree valve.
4. Pipes with medium containing suspended particles.
5. Urban gas pipeline.
Water works.

Advantages
The flow resistance is similar to the flow resistance of a short tube. Plate gate valves with guide holes are installed on the pipe and can be pigged directly by a pig. Because the gate slides on two seats, the plate gate fluid can be applied to the medium with suspended particles, and the sealing face of the plate gate valve is actually automatically positioned. Seat sealing faces are not damaged by thermal deformation of the body. And even if the valve is closed in a cold state, the hot elongation of the stem does not overload the sealing surface. At the same time, when the valve is closed, the plate gate valve without guide hole does not require high precision of the closing position of the gate plate, so the electric plate valve can control the opening and closing position by stroke.

Disadvantages
When the pressure of medium is low, the sealing force of metal seal cover is not enough to achieve satisfactory sealing. On the contrary, when the pressure of medium is high, if the sealing surface is not lubricated by the system medium or external medium, the sealing surface can be damaged too much. Another disadvantage is that a circular gate moving sideways on a circular channel is sensitive to flow control only when it is 50% of the valve position. In addition, when the gate breaks the high - speed and high - density media flow, it will produce violent vibration. It can also be used for throttling if the seat is made into a V port and tightly guided to the gate.

Selection principle

1. For oil and natural gas pipeline, single or double gate plate gate valves shall be used. If it is necessary to clean the pipeline, single gate or double gate plate gate valves with guide holes shall be selected.
2. For transportation pipeline and storage equipment of product oil, single gate or double gate plate gate valves without guide holes shall be selected.
3. For oil and natural gas well head devices, single gate or double gate plate gate valves with guide holes of the floating stem are selected, most of which are API16A standard, with pressure classes of API2000, API3000, API5000, API10000, API15000 and API20000.
4. For pipe with suspended particulate media, use knife plate gate valve.
5. For urban gas pipeline, single or double gate soft-sealing surface bar gate valve is used.
6. For urban water works, single or double gate plate gate valves without diversion hole are selected.