Q. How long have you run an engine?
Q. Have you done your own firing?
Q. What kinds of engines have you run?
Q. What would be your first duty if called upon to take charge of an
engine?
A. To ascertain the exact condition of the boiler and all its
attachments, such as safety valve, steam gauge, water gauge and cocks,
pump, injector, blow-off valve, etc.; also the engine.
Q. How often would you blow off your boiler?
A. Once a week or month, according to the condition of feed water used.
Q. How many feet of heating surface is allowed per horse-power by
builders of boilers?
A. From 12 to 15 square feet for flue and tubular boilers.
Q. How much steam pressure will be allowed on a boiler 40 inch
diameter, ⅜ thick, 60,000 pounds T. S., ⅛ T. S. factor of safety?
A. One-sixth of tensile strength of plate multiplied by thickness of
plate, divided by one-half of the diameter of boiler gives safe working
pressure.
Q. How do you estimate the strength of a boiler?
A. By its diameter and thickness of material, single or double riveted.
Q. Which is the stronger, single or double riveted?
A. Double riveted is from 14 to 18 per cent. stronger than single.
Q. What is the use of a mud drum on a boiler?
A. To collect all the sediment from the water used in the boiler.
Q. What causes sediment to accumulate in boilers?
A. The use of impure or muddy water.
Q. How often should it be blown out?
A. Three or four times a day.
A. How much grate surface do boiler makers allow per horse-power?
A. About two-thirds of a square foot.
Q. What is the steam dome of a boiler used for?
A. For dry steam to collect in.
Q. Of what use is a safety valve on a boiler?
A. To prevent overpressure.
Q. What is your duty with reference to it?
A. Open it once or twice a day to see that it is in good order.
Q. Of what use is a check valve?
A. To prevent the water in boiler from returning into the pump or
injector.
Q. What effect has cold water on hot boiler plates?
A. It will fracture them.
Q. How should the gauge cocks be located on a boiler?
A. So that the lowest gauge cock is about 1½ inches above the top row
of flues.
Q. Where should the blow-off valve be located?
A. At the bottom of the fire box in locomotive style of boiler, or in
the mud drum when used.
Q. How would you have check valve arranged?
A. With a stop cock between the boiler and check valve.
Q. Does a man-hole in the top shell of boiler weaken it?
A. Yes, to a certain extent.
Q. How many valves in a common plunger pump?
A. Two, a receiving and a discharge valve.
Q. How are they situated?
A. One at suction, the other at discharge end.
Q. How do you find the proper size of safety valve for boiler?
A. Two square feet of grate surface is allowed for one inch area of
common lever valve, or three square feet of surface to one inch area of
spring valve.
Q. Why do pumps fail to work at times?
A. Leak in the suction, leak around the plunger, leaky check valve, or
valve out of order.
Q. Why do injectors fail to work at times?
A. Leak in suction, grit or dirt under seat of valve, or valve not
seated properly.
Q. How often should a boiler be examined and tested?
A. Twice a year at least.
Q. How would you test a boiler?
A. By tapping it with a light hammer, and hydrostatic test, using warm
water.
Q. Where does the feed water enter the boiler?
A. Below the water level, where the feed water will not strike the
heated plates.
Q. What causes priming of boilers?
A. Too high water, not steam space enough, dirty feed water,
misconstruction of boiler, or engine being too large for its capacity.
Q. How can you keep boilers clean or remove scale from them?
A. By regularly cleaning them thoroughly, and by the use of compounds.
Q. If you found a thin plate in your boiler what would you do?
A. Patch it on the inside, first cutting out the damaged part.
Q. Why cut out the damaged part of sheet, when putting on a patch?
A. To allow the water to rest against the patch to protect it from the
intense heat.
Q. What would be the result if the damaged part of sheet was not cut
out?
A. The water not coming in contact with the patch, it would soon bulge
from the heat and crack.
Q. Why patch it on the inside?
A. Because the action that has weakened the plate before will act upon
the patch, when this is worn it can be replaced.
Q. If you found you had to put on several patches what would you do?
A. Reduce the steam pressure.
Q. If you found a blister what would you do?
A. Cut it out and put a patch on the fire side.
Q. If you found a plate buckled or sagged what would you do?
A. Put a stay bolt through the center of the sag.
Q. What would you do with a cracked plate?
A. Cut out the damaged part and put a patch over it.
Q. How would you change the water in a boiler when steam is up?
A. By supplying more feed water and opening the surface blow-off at
short intervals.
Q. When blowing off a boiler, would you leave the blow-off cock to
attend to other work?
A. Never.
Q. What would you do to relieve the pressure on the boiler if the
safety valve was stuck and steam constantly rising?
A. Cover the fire with coal or ashes, close draught door and open
damper in smoke box; work off the steam with the engine and when boiler
has cooled down put the safety valve in working order.
Q. What may be the result if you allow the water in the boiler to get
low?
A. Burning of the crown sheet and flues and perhaps cause an explosion.
Q. Would you turn feed water into a boiler in which the water was very
low?
A. Never, without first pulling the fire or covering it with dry ashes
and allowing the steam to go down.
Q. If you allow water in the boiler to get too high what would be the
result?
A. It would cause priming or foaming.
Q. Is priming or foaming dangerous to an engine?
A. Yes. It may cause breaking of cylinder head and wrecking of the
engine.
Q. What are other causes for foaming or priming of a boiler?
A. Dirty and impure water.