Page 375 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

354 Major Process Equipment Maintenance and Repair

and serve as a guide for establishing routine operating procedures for
such general purpose turbines as Elliott Company’s Type YR machines.*
In establishing the specific procedures applicable to a given turbine
type or vendor’s model, it is clearly advisable that operating and mainte
nance personnel review the technical material supplied with the equip-
ment. Moreover, it is equally advisable that all appropriate persons fa-
miliarize themselves with the safety precautions and operating
procedures for turbines. Particular attention should be directed to the
warning and caution notes in this chapter.

Steam Supply

Steam should be free from moisture and preferably superheated. A re-
ceiver type separator with ample drains should be provided ahead of the
shut-off valve to prevent water from entering the turbine. When a separa-
tor is not provided, a continuous drain must be connected to the lowest
point of the steam inlet piping.
The steam strainer (2, Figure 8-4) protects the turbine from large parti-
cles of scale, welding beads, etc. This strainer does not guard against
abrasive matter, boiler compound, acids, or alkaline substances, all of
which may be carried over in the steam. These substances may corrode,
erode, or form deposits on the internal turbine parts, thus reducing effi-
ciency and power. It is necessary that feedwater treatment and boiler op-
eration be carefully controlled to ensure a supply of clean steam, if pro-
longed satisfactory operation is desired.

Safety Precautions
1. Do not operate the turbine if inspection shows that the rotor shaft
journals are corroded.
2. Be sure the rotor is not rubbing any stationary parts and rotates
freely by hand before starting.
3. Check that all piping and electrical connections are made before op-
erating the turbine.
4. Ensure that all valves, controls, trip mechanisms and safety devices
are in good operating condition.
Under no circumstances should the trip valve be blocked or held open to
render the trip system inoperative. Overriding the tnp system, and allow-
ing the turbine to exceed the rated (nameplate) trip speed may result in

* Source: Elliott Company, Jeannette, Pa. 15644. Adapted by permission.