Page 399 - Centrifugal Pumps 2E

364 Centrifugal Pumps: Design and Application

Temperature Control. At the seal faces, temperature control is desirable
because wear is a function of temperature. Heat at the seal faces will
cause the liquid film to vaporize, generating still more heat. Thermal dis-
tortion may also result, which will contribute to seal leakage. Therefore,
many applications will require some type of cooling.

Table 17-1
Coefficient of Friction for
Various Seal Face Materials
(Water Lubrication, PV—100,000 Lb/In. W X Ft/min. John Crane Inc.)

SLIDING MATERIALS COEFFICIENT
OF FRICTION
PPIMAPY RING MATING PING

CARBON-GRAPHITE CAST IRON 0.07
(RESIN FILLED) CERAMIC
0.07
TUNGSTEN CARBIDE 0.07
SILICON CARBIDE 0.02
SILIC3NI2ED CAR8QN 0.015
SILICON CARBIDE TUNGSTEN CARBIDE 0.02
SILICONI2ED CARBON 0.05
SILICON CARBIDE 0,02
TUN3STEN CARBIDE 0.08