Seal leak paths

SEAL LEAK PATHS S019

In this illustration the lapped seal faces are being held together by multiple springs and the pressure of the fluid in the stuffing box.

If we look at the picture closely we can see six potential leak paths for the pump fluid:

  • The O-ring located between the seal sleeve and the pump shaft is called the static O-ring. It is a potential leak path.
  • The O-ring between the seal sleeve and the outside barrel is called the dynamic O-ring. It is a potential leak path also.
  • In this example the rotating face has been press fit into the outer barrel of the seal. This face is usually a form of carbon/ graphite. There is a potential leak path between the carbon/ graphite and the outer barrel where the carbon has been inserted.
  • The stationary face is normally the hard face and in this instance is a clamped “L” shaped design with gaskets on either side. The gasket located between the stationary face and the pump stuffing box is a potential leak path also.
  • There is a potential leak path between the carbon rotating face and the stationary hard face.
  • Although not shown in the illustration, many pump shafts are specified with a shaft sleeve for corrosion resistance or to position the impeller in a double ended design. This shaft sleeve must be sealed to the shaft by a gasket or some other means. This gasket is a leak path also.

There are a variety of other mechanical seals available with different potential leak paths. Check your design carefully.

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  • On February 17, 2018