Basic Introduction to Power Station Gate Valves

The power station gate valve, also known as a power station-specific valve, is primarily used in piping systems of thermal power stations to cut off or connect piping media. Suitable media include water, steam, and other non-corrosive substances. The distinctive feature of the power station valve compared to other valve products is its high temperature and high pressure resistance.

The unique self-sealing design ensures the higher the pressure, the more reliable the seal. Due to the specific performance and technical characteristics, as well as the unique operating conditions, the product has developed distinctive features that cannot be replaced by other products.

Design Specifications for Power Station Gate Valves

Design and Manufacturing: GB/T12234, ASME B16.34

Structural Length JB/T3595

Interface Connection Dimensions: JB/T3595, GB/T12224

Inspection and Testing JB/T3595 MSS SP61

Pressure and Temperature Reference JB/T3595 ANSI B16.34

Advantages of Power Station Gate Valves:

The fluid resistance is low, with the resistance coefficient being equal to that of a pipe section of the same length.

2. Simple structure, compact size, and light weight.

3. Rigid and reliable, the sealing surface material of the gate valves is widely used plastic, offering excellent sealing properties, and has also been extensively applied in vacuum systems.

4. Easy to operate, with quick opening and closing. It takes just a 90-degree rotation to go from fully open to fully closed, making it convenient for long-distance control.

5. Easy maintenance, the gate valve structure is simple, and the sealing rings are usually movable, making disassembly and replacement quite convenient.

6. When fully open or fully closed, the sealing surfaces of the sphere and valve seat are isolated from the medium, preventing erosion of the valve sealing surface during passage of the medium.

7. Wide application range, from a few millimeters to several meters in diameter, suitable for both high vacuum and high pressure conditions.

Structural Features of Power Station Gate Valves:

1. The feature of zero friction in opening and closing completely resolves the issue of traditional valves, which are affected by friction between sealing surfaces.

2. Upstream structural design. Valves installed on pipelines can be directly inspected and maintained online, effectively reducing downtime and lowering costs.

3. Single Valve Seat Design. Eliminates the issue of using safety affected by abnormal pressure rise of the medium in the valve chamber.

4. Low-torque design. The valve rod with a special structural design can be easily opened and closed with just a small handwheel valve.

5.楔形密封 design. The valve achieves sealing by applying mechanical force through the valve stem, pressing the ball wedge against the valve seat. This ensures that the valve's sealing performance is unaffected by pressure differences in the pipeline, providing reliable sealing under all operating conditions.

6. Self-cleaning structure with a sealed surface. As the sphere moves away from the valve seat, the fluid in the pipeline flows uniformly through the sphere's sealed surface in a 360-degree pattern. This not only eliminates the localized erosion of the valve seat by high-speed fluid but also washes away any deposits on the sealing surface, achieving the purpose of self-cleaning.

The working principle of a power station gate valve:

Initiation Process

In the closed position, the valve body is mechanically pressed against the valve seat by the valve stem.

2. When the handwheel is turned counterclockwise, the valve rod moves in the opposite direction, causing the bottom triangular plane to disengage the ball from the valve seat.

The valve rod continues to rise, interacting with the guide pin within the spiral groove, causing the ball to start rotating frictionlessly.

4. Until fully open, the valve stem reaches its full extension, and the ball rotates to the fully open position.

Closure Process

At shutdown, rotate the handwheel clockwise, which causes the valve stem to descend and the ball to start rotating away from the valve seat.

2. Continue rotating the hand wheel; the valve rod is then actuated by a guide pin embedded in its spiral groove, causing both the valve rod and the gate plate to rotate 90 degrees simultaneously.

At the last moment, the gate body rotated 90 degrees without contact with the valve seat.

4. As the handwheel is turned for the last few rotations, the angular plane at the bottom of the valve rod mechanically wedges against the ball, pressing it tightly against the valve seat for a complete seal.