Page 468 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

Gas Turbines 445

Figure 9-4. Heavy duty industrial turbine (courtesy Westinghouse Canada).

peratures are desired from many units. This has led to a much more con-
servative application of metallurgical and mechanical design.
It is not fair to say that the designers of each of these types of turbines
are not learning from each other. Newer industrial designs are incorpo-
rating some of the advanced blade and vane cooling systems to allow
higher firing temperatures and greater efficiency. Aircraft derivative
manufacturers and their users are “industrializing” their units more as
time progresses to achieve longer uninterrupted run times and longer in-
tervals between overhauls.
Aircraft derivative users have three primary methods of maintenance:
1. Remove gas generators on a regular basis as determined by the
manufacturer and their experience and send them back to the manu-
facturer’s facility for overhaul.
2. Operate a repair facility of their own for most of the routine over-
haul procedures. Procedures which they were unable to perform
could still be contracted to the Original Equipment Manufacturer
(OEM) on a component basis.
3. Enter into a comprehensive service contract with the OEM that would
include the first method as well as periodic servicing and non-intrusive
inspection activities on site. This approach is dealt with on pages 471
to 478.
There are advantages and disadvantages to both of these approaches.
Clearly if you only operate a few turbines and they are of different types
the second approach would not be very attractive. If, however, you oper-
ate many identical units, the savings of the second approach could easily
cut your maintenance budget in half.