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3.11 Leakage
Leakage is the primary concern for mechanical sealing. Mechanical Seal Leakage depends on many factors,
most of which are listed in the table below. Leakage is generally significantly higher during initial startup
when the elastomers are dry and need to be broken-in to allow proper sealing. Afterwards, the elastomers
should seal completely during normal operations.
Possible Causes of Mechanical Seal Failures or Leakage
FAILURES OR LEAKAGE
Dry-Running
Mechanical Shock
Wear on the sliding surfaces
Corrosion on the sliding surfaces or springs
Axial misalignment
Extreme vibrations
Caked-on product on the product-side of the
seal (DAMS)
The seal faces will glue together
Slow leaks are a primary concern as the small amount of liquid tends to evaporate into the atmosphere.
This is unacceptable with toxic or environmentally harmful liquids. The standard for such cases is a Double
Acting Mechanical Seal with a quench medium to flush out and contain dangerous product media in a
separate, closed system.
Due to legal regulations, leaks must be constantly monitored to protect the environment. For maintenance
or cleaning cycles, it is recommended to monitor flushing loss using either a visual flow measurement or a
back-pressure sensor.
mechanical seal cartridge during maintenance and inspection intervals or repairs.
Page 38
advises regularly inspecting and/or replacing the visible O-rings on the
Processtec
POSSIBLE CAUSES
Thermal shock from lack of seal water
Stator installed at the wrong angle
Deposits on the sliding surfaces
Dirt, oil, or grease on the sliding surfaces
Improper installation
Excess loads from pipe connections
Damaged/destroyed atmospheric-side of the
seal (DAMS)
Long storage time and the screws have not
been hand-turned as instructed
3. OPERATION
PROCESSTEC INC. 2022
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