Working principle of 304 stainless steel three-piece ball valve
Three-piece ball valves belong to the manually operated ball valve category. A ball valve uses a ball with a circular passage as its opening and closing element; the ball rotates with the valve stem to achieve the opening and closing action. The opening and closing element of a ball valve is a perforated ball that rotates around an axis perpendicular to the passage, thereby achieving the purpose of opening and closing the passage. Ball valves are mainly used to cut off or connect the medium in pipelines and equipment, and can also be used for fluid regulation and control. Three-piece ball valves have low fluid resistance, simple structure, small size, light weight, tight and reliable operation, convenient operation and maintenance, and will not cause corrosion of the valve sealing surface, making them widely applicable.
Three-piece ball valve features: Nominal pressure: 1.6-6.4MPa; Applicable temperature range: -20~232℃~350℃; Applicable media: water, oil, gas, and some corrosive liquids (W.O.G); Thread type: G·NPT, BSPT, BSP, DIN
I. Opening Process
In the closed position, the ball is pressed firmly 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 plane disengages the ball from the valve seat.
The valve stem continues to rise and interacts with the guide pin in the valve stem’s spiral groove, causing the ball to begin rotating without friction.
Until reaching the fully open position, the valve stem rises to its limit, and the ball rotates to the fully open position.
II. Closing Process
To close, turn the handwheel clockwise. The valve stem begins to descend, causing the ball to leave the valve seat and begin rotating.
Continuing to rotate the handwheel, the valve stem is acted upon by the guide pin embedded in its spiral groove, causing the valve stem and ball to rotate simultaneously by 90°.
Near closing, the ball has rotated 90° without contacting the valve seat.
In the last few rotations of the handwheel, the angular plane at the bottom of the valve stem mechanically weaves and presses against the ball, pressing it tightly against the valve seat, achieving a complete seal.
