Three Piece Ball Valve Working Principle
What is a three piece ball valve?
The three piece ball valve is composed of a valve body, two valve covers, a ball, a valve stem, a packing gland, a handle, a lock nut and other important parts. The three-piece ball valve media can be used from left to right and right to left, clockwise is closed, and counterclockwise is open.
The 3 piece ball valve and the gate valve are the same type of valve, the difference is that its closing part is a sphere, and the sphere rotates around the center line of the valve body to achieve opening and closing. Ball valves are mainly used to cut off, distribute and change the flow direction of the medium in the pipeline.
How does the three piece ball valve work?
The working principle of ball valve is to make the valve unblocked or blocked by rotating the valve stem. The ball valve switch is light, small in size, can be made into a large diameter, reliable sealing, simple structure, convenient maintenance, the sealing surface and the spherical surface are often closed, and are not easily eroded by the medium, and are widely used in various industries.
Open process
In the closed position, the ball is pressed against the valve seat by the mechanical pressure of the valve stem. When the handwheel is turned counterclockwise, the valve stem moves in the opposite direction, and its bottom angular flat disengages the ball from the valve seat. The stem continues to lift and interacts with the guide pins in the helical grooves of the stem, causing the ball to begin to rotate without friction. Until it reaches the fully open position, the ball valve stem is lifted to the limit position, and the ball rotates to the fully open position.
Shutdown process
To close, turn the handwheel clockwise, the stem begins to drop and the ball leaves the seat and begins to rotate. Continue to rotate the handwheel, the valve stem is acted by the guide pin embedded in the spiral groove on it, so that the valve stem and the ball rotate 90° at the same time. Just before closing, the ball has rotated 90° without making contact with the seat. During the last few turns of the handwheel, the angular flat at the bottom of the valve stem mechanically wedges against the sphere, making it tightly pressed against the valve seat to achieve a complete seal.
Features of three-piece ball valve:
- Full diameter and large flow design, large flow and small resistance.
- Three-piece valve body structure, pressure resistance, corrosion resistance, such as hard seal, it can withstand high temperature.
- The whole body is made of stainless steel, and the seal is made of PTFE, which has good sealing effect and corrosion resistance.
- Adapt to temperature: soft seal -40-200 degrees, hard seal -40-400 degrees.
- Rotate the switch by 90 degrees, which can achieve the function of quick switch off.
- Use pressure 6KG-64KG pressure, 0.6MPG-6.4MPG (within 1000PSI)
The three piece ball valve is a relatively new type of ball valve. It has some unique advantages of its own structure, such as no friction on the switch, the seal is not easy to wear, and the opening and closing torque is small. This reduces the size of the mounted actuator. Equipped with a multi-turn electric actuator that adjusts the medium and closes tightly. ATO 3 piece ball valve sizes are available in 1", 1/2" and 3".
