Flowserve Mark 3 ISO Durco - Manual (Page 22)

DURCO MARK 3 ISO CLOSE COUPLED ENGLISH 26999985 02-14
Page 22 of 32
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6.10.4 Impeller assembly and setting - double seal
For double seal arrangements, a sub assembly of the
integral impeller/stub shaft, seal housing, seal cover
and seals is required.
a) Fit the impeller shaft through the seal housing.
b) Refer to seal manufacturer's instructions to position
the mechanical seal rotating elements. The short
outboard seal is easier to assemble with a special
tapered tool fitted to the end of the shaft.
c) When the seals are in position, fit the seal cover
and tighten all fasteners.
d) Whilst supporting the seal housing, locate the
stub shaft on the adjustment stud to ensure
engagement. (Large pump sizes have a tapped
hole for fitting a lifting eye to assist with this
procedure.)
e) Rotate the impeller until the back clearance is
approximately 1 mm (0.04 in.).
f) Long studs may be used initially to locate the
seal housing and support the weight whilst the
impeller is rotated.
g) Ensure all flush connections are reconnected.
h) Refer to section 5.2, Setting impeller clearance,
for setting dimensions and coupling fitting
instructions.
i) Fit the casing gasket and pump casing and
tighten all casing fasteners.
j) Check that the shaft can turn freely without binding.
6.10.5 Impeller assembly and setting - cartridge
seal
a) Loosely fit the cartridge seal to the seal housing,
then fit and tighten onto the bracket.
b) Apply anti-seizing compound to the adjustment
stud.
c) Insert the impeller shaft and screw on until the
gap between the impeller and seal housing is
approximately 1 mm (0.04 in.).
d) Fit the casing gasket and pump casing and
tighten all casing fasteners.
e) Refer to section 5.2, Setting impeller clearance, for
setting dimensions and coupling fitting instructions.
f) To set, or reset, a cartridge seal having a PTFE
setting ring-throttle and no separate setting clips,
finger tighten the seal cover studs nuts, then fully
torque up the sleeve screws.
g) Torque up the seal cover studs nuts.