Hale MG User Manual
Page 17
Muscle Pumps
1-10
A clearance ring usually has a radial clearance of
about 0.0075-inch or a 0.015-inch diameter.
However, the clearance will increase over time as
the pump is operated. Wear is due to foreign
material found in the water. Clearance rings are
designed for replacement as the clearance increases
from usage and wear.
If a pump is operated without water for extended
periods or without discharging water, it may
overheat. This may damage the pump and the drive
mechanism.
Bearings
Bearings support and align the impeller shaft for
smooth operation (see figure 1-7).
Pump Seals
There are two types of seals available for Hale
midship pumps, packing and mechanical.
Packing
Packing available on Qmax and Qtwo pumps
forms a nearly watertight seal at the point where
the shaft passes from the inside to the outside of
the pump (see figure 1-9). Packing material is
cooled with pump water. The packing gland should
not be excessively tightened, or the material will
lose its built-in lubrication and dry out, which may
result in damage to the pump. The single packing
gland is located on the low-pressure side of the
pump. Its split design promotes ease of repacking.
The packing nut is full circle threaded type to exert
a uniform pressure on packing and to prevent
cocking and uneven packing load. The packing is
easily adjusted with a rod or screwdriver. The
packing rings are made of a combination of unique
materials and have sacrificial zinc separators to
protect the pump shaft from galvanic corrosion.
Packing material may also deteriorate if the pump
is kept dry for long periods of time during winter
months (for example, to prevent freezing). In this
case, charging the pump with water at least once
weekly will prevent deterioration. See the
Maintenance Instructions in Section 3 for details.
Figure 1-9. Pump Packing
PACKING COOLING PASSAGE
PACKING HOUSING
(3) .005 THK FOIL PACKING
SEPARATORS PER JOINT
(TOTAL 12 REQUIRED)
IMPELLER END
PACKING LANTERN
(4) 7/16 SQUARE
PACKING RINGS
PACKING GLAND LOCK
PUMP SHAFT
SLOTTED PACKING NUT
SPLIT PACKING GLAND