Page 290 - The Tribology Handbook

Packed glands B25

r A=7W
FIRST OBSTRUCTION
/ P-

ROTATING SHAFT RECIPROCATING SHAFT
(DEPTH 7W APPLIES WHEN LANTERN GLAND IS USED)
Figure 25.11 Typical gland dimensions for rotating and reciprocating shafts

Pump shafts, valve stems and reciprocating rams should have a surface finish of better than 0.4 pm Ra. Their hardness
should not be less than 250 Brinell.
Rings should be cut with square butt joins and each fitted individually with joins staggered at a minimum of 90". After
applying a small degree of compression to the complete set, gland nuts must be slackened off to finger tight prior to start up.
Once running, any excessive leakage can then be gradually reduced by repeated small degrees of adjustment. The major
cause of packing failure is excessive compression, particularly at the initial fitting stage.
Further advice may be obtained from packing manufacturers.

B25.4