Page 34 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

Installation, Maintenance, and Repair of Horizontal Pumps 19

8. Tighten the equipment hold-down bolts and recheck the align-
ment; adjust as necessary.

Check for a “soft foot” by loosening each hold-down bolt in turn
while measuring with a dial indicator movement between machine
foot and soleplate or baseplate. If movement exceeds approxi-
mately .OOl-in. (.025 millimeters) at any foot, shim changes
should be made to eliminate the “soft foot” and alignment re-
checked before proceeding.

9. The alignment should be checked and recorded after both bolt-up
of all piping to the pump and bolt-up of all piping to the driver. No
significant strain should be present as indicated by any change in
the pump-driver alignment. A change in alignment of more than
.001-in. from the pipe-free condition should be investigated and
the piping strain corrected. When “cold set” has been included in
the piping design, the final alignment must be checked and the tol-
erances met after the system has reached normal temperature.

10. Pumps operating at over 300°F and all steam turbine drivers
should be hot aligned; that is thermally cycled to normal operating
temperatures and realigned, if at all possible, while hot. This will
ensure that the alignment tolerances are still being met under oper-
ating conditions.

1 1. After the final alignment has been approved, the support pads for
the pumps and drivers should be drilled at two locations and ta-
pered dowel pins with threaded ends to facilitate removal should
be installed. Unless specifically located by the equipment manu-
facturer, the dowel pins should be placed near the thrust bearing
end of the equipment.

PreOpgrational Checks

The following is a checklist of items that should be looked at before
actually starting up the equipment. The list is by no means complete for
all types of machinery but should act as a mind jogger before initial
startup. Refer also to Appendix 1B.

1. For pumps with double mechanical seals or packing with external
gland oil, the gland oil supply piping should be cleaned by oil or
solvent flushing prior to connecting to the pump. The oil system
should be flushed at the design flow rate at a temperature of about