The advantages and disadvantages of the fixed ball valve:

Advantage
1, double block and emission features: the fixed ball Instrumentation ball valve seat by spring preload variable, whether the valve is fully open or fully closed state, on the downstream side of the seat so that the fluid is blocked, the body cavity retentate through the discharge valve discharge.
2, automatic pressure relief feature: the Needle valves body cavity retention medium caused by temperature rise when an abnormal pressure, without going through the safety valve, and the valve seat can only function of pressure relief automatically, which ensure that the safety valve in the delivery of liquid medium is very important.
3, fire safety structure: fire safety valve functions are available, the design, manufacture were to follow API 607 and API 6FA specifications.
Disadvantages
1, sealing grease emergency ambulance: as the foreign media or the fire caused the valve seat sealing failure, valve grease and grease gun provides a fast connection, import pump conveniently and quickly injected into the valve seat seal grease sealing parts, ease leak.
2, reliable stem sealing and low operating torque: in addition to setting the standard sealing ring, the packing gland has also set up O type sealing ring, double seals to ensure the reliability of the valve stem seals; addition of graphite filler and seal fat into the fire so that the valve stem leakage to a minimum. Stem bearings and thrust bearings so that the valve is easy to operate.
3, full size or reduced diameter: according to the selection of full size or necking structure needs. Full bore valve flow aperture consistent with the pipeline diameter, for pipeline cleaning.
4, the stem can be extended: according to the requirement of the installation or operation, the valve stem can be lengthened. Extension rod ball, especially suitable for urban gas pipeline laying occasions need buried. Long stem size according to customer needs to be determined.
5, the operation is flexible: the use of a small friction coefficient and good self lubrication of the valve seat and stem bearing, greatly reducing the valve operating torque. Therefore, even if not provided in the case of grease, but also the long-term flexibly operate on valve.