BOILER TUBE DEFORMITIES
IN ANSWERING QUESTIONS 6-22 THROUGH 6-25,
REFER TO FIGURE 6C.
6-22. Very mild overheating for a short period of
6-23. Caused by a mechanical process, such as
6-24. Low water for an extended period of time at
high furnace temperatures:
6-25. Sudden cooling of overheated tubes:
6-26. Improper fabrication of tubes is most likely to
result in which of the following conditions?
Mechanical fatigue cracks
The basic reason for tube failure caused by
fireside and waterside deposits is that the
deposits result in which of the following
Tube wall lamination
Abundant water combining with soot on
firesides of tubes may result in the formation
of what substance?
Steam drum protection plates are most likely
to be damaged when what condition exists?
Gas passages are clogged
Superheater is overfired
3. Steam pressure is formed too fast
Brickwork adjacent to the superheater
headers is damaged
When testing the functions of automatically or
manually controlled devices that interfere with
steam distribution, you should ensure that
which of the following main distribution valves
2. Gas and water
4. Water and steam
When CO2 or O2 measuring devices are not
available, you can use which of the following
indications as a guide for checking the air-fuel
ratio on a small boiler?
Appearance of the fire