The fixed ball valve adopts the upper and lower stem fixed spool (shaft support) and movable seal seat design. Jobs are more stable. With automatic compensation function, two-way sealing valve seat without clearance rotation with a large shear force and self-cleaning function. Especially suitable for imperial fiber and suspension with small solid particles and viscous media. Stationary ball valve products can be widely used in papermaking, petrochemical, chemical, metallurgy, electric power, environmental protection, petroleum, light industry and other industrial departments in the automation control system.
Structural characteristics of fixed ball valve:
1. Obstruction and excretion:
The fixed ball valve adopts the spring pre-tightening floating valve seat, whether the valve is in the fully open or fully closed state, the upper and lower side of the valve seat to block the fluid, the body cavity residual material is discharged through the discharge valve.
With the valve in the closed position, the seats on the upstream and downstream sides block the flow. Fixed ball valve in the body of the cavity of the product can be discharged toughness, discharge device has the following functions:
(1) Can check whether the valve seat leakage damage;
Reduce the pollution of medium replacement on fixed ball valve;
③ Under the working pressure, when the valve is fully open or fully closed, the stem stuffing box can be replaced.
2. Automatic pressure relief:
When the temperature of the medium in the valve body cavity increases and causes abnormal pressure increase, it does not need to pass the safety valve, but only depends on the function of the valve seat to automatically relieve pressure, which is very important to ensure the safety of the valve when transporting the liquid medium.
When the abnormal pressure is increased due to the temperature rise of the stagnant medium in the ball valve chamber, the valve seat is removed from the ball automatic pressure relief (Figure 9) or the safety valve installed on the valve body (Figure 10) to ensure the safety of the system.
3. Completely sealed:
Fixed ball valve has a unique sealing way, so that the fluid completely blocked.
4. Fire structure:
In case of fire or abnormal temperature caused by softening and burning of Teflon field base. To prevent fire expansion, the stationary ball valve operates reliably, while the eye seat support can be in contact with the ball (Fig. 11: instantaneous sealing). Comply with APL 607.
5. Sealing emergency grease rescue
Due to the unexpected failure of the seat seal due to foreign matter in the medium or fire, the grease valve provides a quick connection with the grease gun to easily and quickly inject the sealing grease into the seat sealing area to mitigate leakage.
6. Reliable stem sealing and low operating torque
In addition to the standard sealing ring, the packing gland is also provided with an "O" type sealing ring, double sealing to ensure the reliability of the stem sealing; Additional graphite packing and seal grease injection minimizes stem leakage after fire. Stem sliding bearings and thrust bearings make the valve easy to operate.
Fixed ball valve operation use
1. Make sure the pipeline and fixed ball valve have been flushed before operation.
2 valve operation according to the size of the actuator input signal to drive the valve stem rotation: forward rotation 1/4 (900), the valve off. Reverse 1/4 turn (900) to open valve.
3. When the direction indicating arrow of the actuator is parallel to the pipeline, the valve is in open state; When the indicating arrow is perpendicular to the line, the valve is closed.
The advantages of fixed ball valve:
1. Sealing emergency grease rescue: due to the unexpected failure of the seat seal caused by foreign bodies in the medium of the fixed ball valve or fire, the grease valve provides a quick connection with the grease gun, and the import pump can easily and quickly inject the sealing grease into the sealing part of the valve seat to relieve the leakage.
2, reliable stem sealing and low operating torque: in addition to the fixed ball valve is provided with a standard sealing ring, the packing gland is also provided with an O-ring, double sealing to ensure the reliability of the stem sealing; Additional graphite packing and seal grease injection minimizes stem leakage after fire. Stem sliding bearings and thrust bearings make the valve easy to operate.
3, full diameter or reduced diameter: fixed ball valve can be selected according to the need for full diameter or reduced diameter structure. The flow diameter of the ball valve is consistent with the inside diameter of the pipeline, which is easy to clean the pipeline.
4, the valve stem can be lengthened: according to the needs of installation or operation, the valve stem can be lengthened. Lengthened rod fixed ball valve, especially suitable for urban gas and other needs buried pipeline laying occasions. Extension stem size according to customer requirements.
5, flexible operation: the use of seat and stem bearings with small friction coefficient and good self-lubrication, greatly reduce the operating torque of the valve. Therefore, the valve can be operated flexibly and freely for a long period of time even if no sealing grease is provided.