The working principle and structural characteristics of American standard globe valves

Introduction:

American standard globe valve and flange globe valve belong to the same type of valve. The closing element is a valve disc, and the valve stem rotates around the centerline of the valve body to achieve opening and closing.

working principle:

A、 Opening process

In the closed position, the valve body is tightly pressed against the valve seat by the mechanical pressure exerted by the valve stem.

When the handwheel is turned counterclockwise, the valve stem moves in the opposite direction, and its bottom angular plane causes the ball to detach from the valve seat.

The valve stem continues to lift and interacts with the guide pin in the spiral groove of the valve stem, causing the ball to start rotating frictionlessly.

Until it reaches the fully open position, the valve stem is lifted to the limit position, and the ball rotates to the fully open position.

B、 Closing process

When closing, rotate the handwheel clockwise and the valve stem begins to descend, causing the ball to move away from the valve seat and begin to rotate.

Continuing to rotate the handwheel, the valve stem is subjected to the action of the guide pin embedded in its spiral groove, causing the valve stem and gate to rotate 90 ° simultaneously.

When it was about to close, the brake body had already rotated 90 degrees without contact with the valve seat.

During the last few turns of the handwheel, the angular plane at the bottom of the valve stem mechanically wedges and presses the ball tightly against the valve seat, achieving complete sealing.

Structural features:

1. Open and close without friction. This feature completely solves the problem of traditional [wiki] valves [/wiki] affecting sealing due to friction between sealing surfaces.

2. Top mounted structure. Valves installed on pipelines can be directly inspected and repaired online, which can effectively reduce equipment downtime and lower costs.

3. Single seat design. Eliminating the issue of abnormal pressure rise in the valve chamber medium affecting safety during use.

4. Low torque design. The valve stem with a special structural design can be easily opened and closed with just a small handle.

5. Wedge shaped sealing structure. Valves rely on the mechanical force provided by the valve stem to press the ball wedge onto the valve seat for sealing, ensuring that the sealing performance of the valve is not affected by changes in pipeline pressure difference, and reliable sealing performance is guaranteed under various working conditions.

6. Self cleaning structure of sealing surface. When the sphere tilts away from the valve seat, the fluid in the pipeline passes uniformly along the sealing surface of the sphere at a 360 ° angle, which not only eliminates the local scouring of the valve seat by high-speed fluid, but also washes away the accumulated substances on the sealing surface, achieving the purpose of self-cleaning.