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CAST TRUNNION BALL VALVE
1.Blow-out proof stem
For the purpose of preventing the stem from flying off resulting in abnormal rising of the inner pressure of valve,shoulder is fixed at the lower part of the stem.In addition,in order to prevent leakage resulting from burnout of packing set of the stem in a fire,thrust bearing is set at the contact position of the shoulder at lower part of the stem and valve body.Thus an inverse seal seat is formed which will prevent leakage and avoid accident.
2.Key lock
Locks can be used to lock the manual valve when it is fully open or closed so as to prevent non-working personnel from pulling the handle which may result in misoperation of valve.It can also avoid opening or closing of valve resulting from the shock from pipelines or unpredictable factors that may cause an accident.For working pipelines such as combustible and explosive oil,gas and chemical medium,or for field piping site,the locking mechanism is especially useful.
3.Anti-fire safe design
When the trunnion ball valve be used normally,its sealed by seat and ball surface,seat retainer sealed by O-ring and body,this is soft sealed and reliable sealing.When the seat and O-ring are burnt,the seat retainer and body will be sealed by expanded graphite.Thus act anti-fire safe purpose.
4.Anti-static device
In order to prevent friction among ball,stem and PTFE that generates static electricity which may light the combustibles and explosives that cause an accident,in this ball valve,static-conduction spring is set between the stem and the ball,the stem and the body.Thus static electricity is conducted to ground and system safety is secured.
5.Free leakage of body Sealed construction
The connective position of valve body and bonnet is double sealed by gasket and O-ring,on this base,such factors as fire,high temperature,shock and uneven opening or closing of the torque all can??t induce external leakage.
6. Double block&bleed(DBB)
When ball is full open or close position,the transmitter substance in center cavity of body can be released by drainage and emptying devices.In addition,the over loaded pressure in the center cavity of valve can be released to low pressure end by self relief seat.
7.Emergency sealing
Compound injection holes are designed and compound injection valves are installed at locations of stem/cap and body support of side valve.When sealing of stem or seat is damaged to induce leakage,the compound can be used to do the second time sealing.A concealed check valve is installed in side of each compound injection valve to prevent compound from out flowing due to the action of transmitter substance.The top of the compound injection valve is the connector for fast connection with compound injection gun.
8.Automatic body cavity relief
When the body pressure going up un-normally as the unstable factor,the trunnion ball valve downstream seat will be pushed by unnormal pressure,and the release the un-normally pressure automatically,it doesn't damage to the sealing of upstream seat.
9.Various driving types
The top pad of valve designed according to ISO 5211,which is convenient for connection and exchange of various drivers.The common driving types are manual,electrical,pneumatic and pneumatic/hydraulic
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