Wenzhou Goldtop Valve Co.LTD |
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ISO 5211 Blow-out proof stem Double block&bleed(DBB) 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
cant 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.