1 Piece Ball Valve Advantages And Disadvantages

1 Piece Ball Valve is a type of valve. Its opening and closing member is the gate disc, which moves perpendicular to the flow direction. Gate valves can only be fully opened and closed and cannot be adjusted or throttled. Gate valves employ a forced seal, meaning that when the valve is closed, an external force forces the gate disc against the valve seat to ensure a tight seal.

Fluorine-lined gate valves, in which the gate disc moves linearly with the valve stem, are called rising-stem gate valves (also called rising-stem gate valves). The rising stem typically has a trapezoidal thread that, through a nut at the top of the valve and a guide groove in the valve body, converts rotary motion into linear motion, effectively converting operating torque into operating thrust.

When the valve is opened, when the gate disc is lifted to a height equal to 1:1 times the valve diameter, the fluid passage is completely unobstructed. However, this position cannot be monitored during operation. In actual use, the top of the valve stem, the position where it cannot be opened, is used as the marker for the fully open position. In order to take into account the locking phenomenon caused by temperature changes, the valve is usually opened to the top position and then retracted 1/2 to 1 turn to form the fully open valve position. Therefore, the fully open position of the valve is determined by the position of the gate disc (i.e., the stroke).
Some gate valves have the stem nut mounted on the gate disc. Turning the handwheel rotates the stem, which raises the gate disc. This type of valve is called a rotary stem gate valve or a concealed stem gate valve.
The following precautions should be taken when installing and maintaining fluorine-lined gate valves:
1. The handwheel, handle, and transmission mechanism must not be used for lifting, and collisions are strictly prohibited.
2. The gate valve should be installed vertically (i.e., the stem is in a vertical position and the handwheel is at the top).
3. Install according to the product instructions.
4. If the valve is frequently opened and closed, lubricate it at least once a month.
Main lining materials for fluorine-lined gate valves:
1. Poly(PTFE) (F4)
2. Media: Strong acids, strong alkalis, strong oxidizers, etc.
3. Operating temperature: -200°C to 180°C
Features: Excellent chemical stability, high heat and cold resistance, and a very low coefficient of friction, making it an excellent choice for... It is a self-lubricating material, but has relatively low mechanical properties, poor fluidity, and high thermal expansion.
Perfluoroethylene (FEP) (F46)
Applicable media: Any organic solvent or reagent, dilute or concentrated inorganic acids, alkalis, ketones, aromatic hydrocarbons, chlorinated hydrocarbons, etc.

Operating temperature: -85°C to 150°C

Features: Mechanical, electrical, and chemical stability are essentially the same as F4, but its outstanding advantages include high dynamic toughness, excellent weather resistance, and radiation resistance.

Fluorine-lined gate valves have the following advantages:
1. Low fluid resistance, minimizing scouring and erosion of the sealing surface by the medium.
2. Efficient opening and closing.
3. Unrestricted flow direction, no flow disturbance, and no pressure drop.
4. Simple design, short length, good manufacturing processability, and a wide range of applications.

Disadvantages of fluorine-lined gate valves:
1. Erosion and scratching between sealing surfaces are prone to occur, making maintenance difficult.
2. Larger dimensions, requiring a certain amount of space for opening, and prolonged opening and closing times.
3. Complex structure.