1.Valve leakage reason

Valve leakage includes external leakage and internal leakage .

(1) External leakage

External leakage often been seen at the packing gland and flange connection .Do you know ,why there are leakage at the packing gland ?

1)The type or quality of packing gland does not meet the requirements

2)The structure or size is unreasonable

3)Valve Stem surface is corrosion or friction

The reasons for leakage at the flange connection are as follows:

1）Improper selection of sealing type and gasket type

2）Gasket and fastener materials do not meet the requirements

3）Flange rigidity is not enough

4）Unreasonable pipeline configuration causes excessive additional stress at the joint

In addition, improper installation of packing and gasket, aging loss of packing, deformation relaxation of packing and gasket also often cause leakage.

(2) Internal leakage

Sealing surface damage is the main cause of internal leakage.  Leakage can also occur if the valve body is not rigid enough and the sealing ring is not properly connected.  

2.Solution

The leakage caused by the above reasons should be solved from the design and material selection.  As long as the installation method is improved, it can be solved by replacing the packing, gasket or tightening again.  The main way to prevent internal leakage is to rationally select sealing surface material and improve sealing structure to improve the life of sealing surface.