IN ANSWERING QUESTIONS 6-12 THROUGH 6-17,
REFER TO FIGURE 6A.
When a blistered tube suggests a waterside
deposit, the nature and extant of this deposit
can be determined in what manner?
By punching the tube with tube cleaning
equipment and inspecting the substance
loosened by the wire brush
2. By hitting the blister a sharp blow with a
hammer and inspecting the particles
3. By removing the tube and an adjacent
tube, splitting both, and comparing them
By removing the tube, splitting it, and
examining the watersides of the blistered
6-10. By what means can you measure the amount
of enlargement of a tube if calipers are not
available to you?
2. A section of string and a ruler
A depth gauge
A straight pin through a 3- by 5-inch card
6-11. What is the most common cause of
circumferential grooving on a superheater?
Leaking of the economizer plugs
2. Leaking of the tube seats in the top pass
of the superheater
3. Soot deposits around the tubes where
they enter the headers
Water washing the firesides without
properly drying them
6-12. What tube defects should be entered in spaces
A and B?
Craters and water tracks
2. Fireside burning and craters
3. Steam gouging and fireside burning
4. Water tracks and steam gouging
6-13. At what point does cratering and water
tracking occur almost exclusively?
On the fire row tubes
2. On the tube ends at the water drum
3. At the header ends of the waterwall tubes
At the steam end of the waterwall tubes