•When speaking of
“Balance” in reference to pump seals, we are not talking
about Mechanical or Rotational Balance. Instead, we are
referring to Hydraulic Balance.
•Since mechanical
seals are subject to stuffing box pressure, this pressure is
utilized to achieve and maintain seal face closure in a
non-balanced seal.
•If stuffing box
pressure is very high, typically over 100psi., then the closing
force may be too great to allow the “Boundary Layer Liquid” that
lubricates the faces to be sufficient and the faces will wear
prematurely.
•A balanced seal
compensates for higher pressures by locating the seal faces such
that stuffing box pressure has less effect on face closure.