The valve used for LPG & LNG, as the forced
seal valve,must be pressurized the obturator to make the seal
face non leakage when the valve close.The force of close valve
is mighter then open,because when the flow from obturator inlto
the shaft force of operate should overcome another resistance
which come from the friction of packing and shaft and the thrust
of flow pressure.So we should use a big diameter shaft or the
shaft will bend by the thrust.In the last few years,When the appearance
of a new design for pressure seal bonnet,and the fluid flow directional
of globe valve has changed,from up flow to valve bore.The force
for closing valve become small and the force for opening be mighter,so
the diameter of shaft can be small,under the pressure of the flow.
These are eight technical Specs which we should
note when installation and maintenance valves that use in LPG
& LNG pipe line.
1.Befor the installation of the valve, make sure
the valve's internal bore clean, and should clean the disfigurement
of the valve cause by the transport.
2.When installation make sure the shaft of butterfly
on horizontal,but for piston valve with their shaft on vertical.
3.Before the using,you should debugging the actuator,make
sure all the fuction of the actuator performance wonderful.And
also for the limit pitch and the control of protection for over
torque are all credibility.
4.Before the debugging of the valve's actuator,make
sure all the part should be add enough grease.
5.Before starting the motor actuator, you should
read the attached manual of motor actuator more carefully.
6.After using the valves,you should observe operating
conditions regularly,and if find some problem should deal with
it in time.
7.Add the lubricate grease regularly, to keep each
part working in good lubricate condition.
8.After using some time of the valve,you find the
piston of the valve can not be shut tightly and have some leakage,pls
check and renew the piston ring.
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