A soft seated side-entry ball valve can leak through
the body/body end connection for the following reasons:
The body/bonnet bolts have inadequate torque.
Body studs and nut bearing surfaces must be properly
lubricated with a HD grease. As much as 50% of the applied nut torque
can be wasted in the case of improper lubrication.
Remove one nut at a time and lubricate the stud threads and the nut
side facing the body end. Torque each bolt to the required level.
Torque values for side-entry ball valves are found in the appropriate
manuals which can be downloaded from the Velan website.
The valve is inappropriately installed in the piping
system causing excess stress.
Visually observe the piping system and verify that the
valve is adequately supported. If the valve has flanged connections,
remove the bolting on one side and verify that the pipe and valve
do not separate. If the valve and pipe separate or there is some indication
that the valve is not being supported adequately, modifications to
the piping arrangement will be necessary.
The gasket is damaged.
Remove the gasket and replace with a new gasket. Velan
does not recommend ever reusing a gasket. Each time a valve is disassembled,
a new gasket is required upon reassembly.
There is a casting leak in the valve body around the
gasket area. Leakage might appear to be coming through the gasket
area but is really coming through a crack.
Inspect the leak and determine exactly where it is coming from.
A dye penetrant test is sometimes required to reveal a casting crack.
Most casting cracks can either be repaired in the field or at a Velan
authorized service shop. Velan recommends that it be consulted prior
to the repair of any casting crack on a valve body.
