Page 102 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

Installation, Maintenance, and Repair of Vertical Pumps 87

7. Install the packing gland and draw the gland nuts hand tight. Do not
compress the packing.

8. When a pump is first operated with new packing, it should be loose
enough to allow a small stream of liquid to flow from the gland.
There should be no leakage around the OD of the packing. Do not
operate the pump with packing too tightly compressed, and do not
make final adjustment until the pump has been operated for several
hours. Then tighten the gland nuts alternately, very slowly and
evenly, until the leakage rate is reduced to a steady drip. Gland nuts
should be tightened 1/6 turn (one flat) at a time and the packing leak-
age observed for 10 minutes before tightening another 1/6 turn.
9. Check the gland temperature and loosen the gland nuts to increase
the leakage rate if overheating of the packing is observed. The
gland adjustment should be checked periodically and readjusted as
needed.
Note: Refer also to the packing instructions in Chapter 8 of Volume 2.

Maintenance and Repair of Pump Bearings

Table 2-1 shows nominal diametral clearances for vertical pump bear-
ings. Bearings should always be made from nongalling materials or the
surfaces should be nitrided or overlayed with Stellite or Colmonoy so
that they are nongalling.
Bowl bearings are product lubricated and normally have sufficient dif-
ferential pressure across them to provide ample flow for lubrication and

Table 2-1
Nominal Diametral Clearances for Vertical Pump Bearings

Diametral
Standard Bearing
Shaft Slre Clearance
314 .006
1 .006
13/16 .008
l7/I6 .008
19/16 .009
1l1/16 .009
115116 ,010
23/16 .011
27/16 and larger .012
(Dimensions are in Inches)