ENGINEMAN 1 & C
The diaphragm seal, figure 6-5, consists of a
diaphragm clamped to the crankcase at its outer
circumference and to a fulcrum ring at its center.
The fulcrum ring forms a seal collar which is
locked to the diaphragm. The sealing points are
located (1) between the outer circumference of the
diaphragm and the crankcase, and sealed by a
copper ring gasket; (2) between the fulcrum ring
and the diaphragmsealed at the factory and not
to be broken; (3) between the fulcrum ring and
Figure 6-5.Diaphragm type seal.
the rotating shaft seal collar, and sealed by
lapped surfaces; and (4) between the shaft seal
collar and the crankshaft shoulder, also sealed by
The tension in a diaphragm seal is adjusted
by adding or removing diaphragm-to-crankcase
gaskets to obtain the specified deflection. For
information on handling, cleaning, and replace-
ment of shaft seal assemblies, consult the
Figure 6-6.Unloader mechanism in unloaded position.