8
H-Series
Disassembly
If pumps are to be disassembled on a
regular basis, we recommend that you
establish a pump room with all the neces-
sary tools and equipment for disassembly
and cleaning with a separate “clean” area
for assembly, testing and storing of rebuilt
pumps.
If maintenance is required due to low
delivery or seizure, the following proce-
dure is recommended for disassembly.
NOTE:
Be sure to note the location and
orientation of all parts to ensure reassembly.
Refer to diagrams on pages 6 and 7
for your correct pump type.
NOTE:
Discard all fasteners, packings or
carbon seal plates after burn-out.
1) Remove the seal arrangement .
2) Remove all binder screws.
3) Remove dowels (10) and arbor (5)
with an arbor press in the direction which
disengages the press fit in the shortest
distance.
NOTE:
Dowels and arbors for the HPB,
HLB and HXB are press fit in the front
side plate (1) and slip fit in the center (2)
and rear side plates (3). In the HMB, they
are press fit in the rear side plate. For the
HPB, HLB and HXB, press these parts out
from the front (drive) side and for the
HMB, from the rear (port) side.
4) Separate the plates by lightly tap-
ping them with a soft head hammer. If pry
slots are available in the pump, you may
use them instead of, or in conjunction
with, the above method. In either case,
great care should be taken not to scratch
or damage the internal pump surface
when prying the plates apart.
5) After disassembly, clean all com-
ponents in a glass bead blast cabinet to
remove any debris remaining after heat
cleaning. Alternative, non-destructive
cleaning methods such as water jet or
solvents are also acceptable.
6) Wash components in an ultrasonic
cleaning tank and air dry. Be careful not
to bang parts together.
7) Inspect all parts for nicks, burrs, score
marks and other signs of wear.
The plates and faces of the gears may be
hand blocked on 400/600 grit paper and
any nicks, burrs or sharp edges can be
lightly removed with an Arkansas stone.
Be careful not to round off the edges of
the gear teeth while lapping.
CAUTION:
Since the thickness relation-
ship between the metering gears and
center plate is critical to metering per-
formance, and the center plate is non-
wearing on its sides, lapping these com-
ponents is not necessary and should not
be done under any circumstances.
Place a layer of 400 Grit Emery Cloth
on a lapping block or plate–a granite flat
is suitable. Apply light pressure to the
component and turn it in a figure 8 fash-
ion (as shown in Figure 1 on page 9)
approximately 10 times until a smooth fin-
ish appears. Turning in a circular fashion,
or other non-uniform motion, may cause
the ground holes to lose their perpendicu-
larity to the faces.
Always use clean, lint-free rags and
compressed air to clean components.
Paper towels are not acceptable; they
may leave small pieces of paper and dust
on the components. Use chemical brush-
es to clean between gear teeth, bores,
and reliefs.
8) Replace sleeve bearings as nec-
essary and hone in the plate to the origi-
nal new part specifications.
9) After each resurfacing, carefully
gauge the area between the inlet and dis-
charge ports at the mesh of the gears.
This area, commonly referred to as the
“throat,” is the most critical part of the
plate. Scoring or wear marks here will
allow increased slip from the high-pres-
sure discharge port section across the
throat to the lower inlet port reducing effi-
ciency. Therefore, carefully gauge this
area for flatness after each resurfacing.
10) After all components are “hospital
clean,” the pump is ready for assembly.
