Top Entry Ball Valve

Top Entry Ball Valve 

Top Entry Ball Valve Features

1.Bow-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.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.

3.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.

4.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.

5.Low torque in operation

The self-lubricated bearings are installed at the friction of stem,resulting in wear resistance,fiexibility of operation and low torque.

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 un-normally pressure,and the release theunnormal pressure automatically,it doesn't damage to the sealing of upstream seat.