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How does seal hydraulic balance work?

How does seal hydraulic balance work?
Update Time:2017-10-17

How does seal hydraulic balance work?

  • There are two forces closing the seal faces:
      ①A spring forces caused by the spring, springs, or bellows pushing on the seal face.
      ②A hydraulic force caused by the pressure of the fluid acting on the closing area of the seal faces.
  • There are three forces opening the mechanical seal:
     ①A hydraulic force caused by fluid or vapor trapped between the lapped faces.
     ②Centrifugal force that is causing the rotating portion of the seal to try and become perpendicular to the rotating shaft.
     ③Hydrodynamic forces generated between the seal faces because for all practical purposes liquids are not compressible.
  • We balance these forces by reducing the closing area of the sale faces and thereby reduce the closing force. This is usually done by a small sleeve inserted into the seal or as stop machined into the shaft. Metal bellow seals have an effective diameter measured through the bellows to accomplish the same thing.