overview
Manual ball valve is a type of valve that emerged in the 1950s. In half a century, ball valves have developed into a major type of valve. Ball valves are mainly used to cut off or connect media, and can also be used for fluid regulation and control. V-shaped ball valves can achieve more accurate flow regulation and control, while three-way ball valves are used to distribute media and change the flow direction of media. Manual ball valves are mainly named after the way they are driven, which is through the rotation of a handwheel or handle.
Chinese name: Manual ball valve
English name: Manual Ball Valve

advantage
Manual ball valve is a relatively new type of ball valve, which has some unique advantages in its own structure, such as frictionless opening and closing, low sealing wear, and small opening and closing torque. This can reduce the specifications of the accompanying actuator. Equipped with a multi turn electric actuator, it can achieve adjustment and tight cutting of the medium. Widely applicable to working conditions such as petroleum, chemical, urban water supply and drainage that require strict cut-off.
Manual ball valves are mainly used in pipelines to cut off, distribute, and change the flow direction of media. Ball valve is a new type of valve widely used in recent years, which has the following advantages:
1. The fluid resistance is small, and its resistance coefficient is equal to that of a pipe segment of the same length.
2. Simple structure, small size, and light weight.
3. Tight and reliable, the sealing surface material of ball valves is widely made of plastic, with good sealing performance, and has also been widely used in vacuum systems.
4. Easy to operate, quick opening and closing, only need to rotate 90 ° from fully open to fully closed, making it convenient for remote control.
5. Easy maintenance, simple ball valve structure, and generally movable sealing rings make disassembly and replacement relatively convenient.
When fully open or fully closed, the sealing surfaces of the ball and valve seat are isolated from the medium, and when the medium passes through, it will not cause erosion of the valve sealing surface.
7. It has a wide range of applications, with diameters ranging from a few millimeters to several meters, and can be used from high vacuum to high pressure. When the ball rotates 90 degrees, it should appear spherical at both the inlet and outlet to intercept the flow.

Classification and Installation Maintenance
Manual ball valves can be divided into straight through, three-way, and right angle types according to their channel positions. The latter two types of ball valves are used for distributing media and changing the flow direction of media. The installation and maintenance of three piece ball valves should pay attention to the following matters:
1. Leave a position for the valve handle to rotate.
2. Cannot be used for throttling.
Ball valves with transmission mechanisms should be installed upright.

Working principle
The working principle of a manual ball valve is to rotate the valve core to make the valve unobstructed or blocked. Ball valve switches are lightweight, small in size, can be made into large diameters, reliable in sealing, simple in structure, easy to maintain, and the sealing surface and spherical surface are often in a closed state, which is not easily eroded by media. They are widely used in various industries.
Its working principle is as follows:
Opening process
In the closed position, the ball is tightly 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 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.

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 both the valve stem and the ball to rotate 90 ° simultaneously.
When it was about to close, the sphere 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 characteristics
1. Open and close without friction. This function completely solves the problem of traditional valves 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.