Clearance rings, Mechanical seal, Figure 2-14: typical mechanical seal overview – Hale 80FC User Manual
Page 34: Pump components - continued
❑ Introduction
34
Pump Ends
p/n: 029-0020-61-0
Clearance Rings
Clearance rings prevent pressurized water that is leaving the pump volute
from returning to the intake of the impeller. Clearance rings at the impeller
intake also prevent leakage, accomplished by limiting the radial clearance
between the spinning impeller and the stationary clearance ring. Also see
Figure 2-12: “Typical Pump and Gearbox Overview” on page 33.
Typically, a clearance ring has a radial clearance of about 0.0075” (0.191
mm) or between 0.015” to 0.020” (0.381-0.508 mm) per side. However, due
to foreign material found in the water, this clearance increases over time
as the pump is operated. Clearance rings are designed for replacement
when wear limits cause the pump to exceed NFPA satisfactory
performance.
Mechanical Seal
The “maintenance-free,” mechanical seal is common to Hale pumps. (See
Figure 2-14: “Typical Mechanical Seal Overview,” on page 34.)
The stationary seat
is in constant con-
tact with a rotating
seal ring to prevent
leakage. The seal-
ing diaphragm is
made of a rubber
elastomer specifi-
cally designed for
high-temperature
operations.
Note: Mechanical
seals do not drip
like older pump
packing. A Hale
pump with a drip from the seal requires service.
WARNING !
IF A PUMP IS OPERATED WITHOUT WATER FOR EXTENDED PERIODS, OR
WITHOUT DISCHARGING WATER, IT COULD OVERHEAT. THIS CAN DAM-
AGE THE MECHANICAL SEAL OR THE DRIVE MECHANISM.
Figure 2-14: Typical Mechanical Seal Overview