1. Failure analysis caused by installation, operation
(1) Leakage occurs during water or static pressure test Due to poor installation, leakage may occur when the mechanical seal is filled with water or static pressure test. There are the following aspects of poor installation.
a. The moving and static ring contact surfaces are not flat, and there are bumps and damages during installation.
b. The dynamic and static ring seals are incorrectly sized, damaged or not pressed.
c. There are foreign objects on the surface of the moving and stationary rings.
d. The direction of the V-shaped sealing ring of the moving and static ring is reversed, or the opposite side is installed.
e. The set screw is not tightened and the spring seat is retracted.
f. Leakage at the bushing, the seal is not installed or insufficiently pressed.
g. If the direction of the shaft is broken by hand, there are the following reasons: the spring force is not uniform, the single spring is not vertical, and the length of the multiple springs is small or small; the end face of the sealing cavity is not perpendicular to the axis.
h. Static ring compression is uneven.
2. Periodic leakage caused by installation, operation, etc.
During operation, if the axial impeller of the pump impeller exceeds the standard, the periodic vibration of the rotating shaft is unstable, and the process operation is unstable, the pressure in the sealed chamber often changes, causing periodic leakage of the seal.
3. Frequent leakage
a. The deformation of the moving ring and static ring contact end faces will cause frequent leakage. If the end face is too large, the friction heat causes thermal deformation of the moving and stationary rings; the structure of the sealing parts is unreasonable, the strength is not enough to cause deformation; the residual deformation due to material processing reasons; the uneven force of the parts during installation is the sealing end face The main cause of deformation.
b. Leakage at the joints of moving and static rings caused by inlaying or bonding causes frequent leakage of the pump. Due to the unreasonable decoration process, residual deformation, improper materials, unsatisfactory interference, and deterioration of the bonding agent may cause seams. leakage.
c. The friction pair is damaged or deformed and cannot run to cause leakage.
d. The friction pair is sandwiched by particulate impurities.
e. The spring is too small.
f. The sealing ring material is incorrect and the swelling is invalid.
g. V-shaped seal is installed.
h. The dynamic and static ring seals are not too perpendicular to the axis.
i. After the sealing ring is pressed, the drive pin and the anti-rotation pin resist the parts.
j. The large spring is not in the wrong direction.
