All piping and ductwork must have provision for ____.
To support the main steam drum ____ shaped hangers are attached to the structural steel.
Buckstays Provide the furnace walls with additional _______Support
U-bolts permit ____ movement of the drum with temperature variations.
The ____ is a major anchor point for other boiler components.
A. Steam Drum
What is meant by the foundation of a boiler?
E. The ground support of the boiler?????
Every boiler must be supported by a good foundation
1. To allow for expansion
2. To avoid movement due to settling
3. To prevent extra stress in connected pipework
4. To allow accurate water indication of the boiler
C. 2, 4????
Why do boilers have allowances for expansion?
1. To prevent the brickwork from cracking
2. To prevent undue stress on the pipework
3. To prevent thermal shock to the steam drum
4. Because the boiler is not always operating at the same temperature
E. 1, 2, 4???
The boiler pressure parts are allowed to expand __________ from the main supports at the top.
Upon completion of the structural steel installation, the “U” shaped hangers are attached to the structural steel for support of the main steam ______.
The drum is supported by U-bolts, which permit linear movement of the drum with ___________ variations.
The _____ is used as the major anchor point for other boiler components, and for this reason, accurate location is important.
The bottom-supported boiler has concrete drum _________, which support the bottom drum and bottom headers.
The boiler tubes themselves are used to support the top _____ in a bottom-supported boiler.
All piping and ductwork must have provision for _______.
Boiler ______ is the term used to describe the airtight metal casing of a boiler wall.
__________ is cement like. It is used to withstand very high temperatures in areas such as burner throats and boiler target walls.
The use of membrane or water-cooled walls has reduced the use of __________ in modern watertube boilers.
Cladding (also called lagging) is the metal covering, which protects the _____ surface of the boiler.
Boiler tubes may be constructed in a seamless form, or they may be ____.
Boiler tubes may be fabricated in a _________ form, or they may be welded.
Tubes for boiler application are either hot-finished, or _____ -drawn depending on the size, tolerance, and finish desired.
_________ tubes have no welded joints.
The function of the rolling mill is to ________ the tube and reduce the wall thickness to the approximate dimensions required.
Directly after rolling and while the tube is still hot, a reeling machine shown in Fig. 14 smooths the outer surface. This is called __________.
Another method used to produce seamless tubes is known as ________.
To form a drum or shell of the required diameter, the plates must be rolled to the correct _________.
The automatic submerged-arc welding process normally makes longitudinal and circumferential ______ in drums.
Drumheads are formed from flat plate by hot pressing with suitable forming dies, and then machining the circumferential welding grooves.
Nozzles and stubs for connecting the drum to tubes and piping are formed by _____ forging from a solid steel cylinder, or “billet”.
The _____ form the connection for the attachment of the boiler steam generating tubes to the drum and the saturated steam outlet tubes from the top or steam space of the drum.
Upon completion of all welding, every drum must be subjected to a preweld heat treatment.
It is not allowed to make any welds directly to the drum _____ stress relieving has been completed.
Postweld heat treatment, often called stress relieving, consists of heating the welded parts uniformly, to a temperature sufficient to relieve most of the stresses created by the heat from the welding. The parts are then cooled at a constant rate.
In the field, the stress relieving of welded pipe joints may be accomplished by means of __________ induction coils, which are wrapped around the welded section of the pipe.
A final test which is carried out in the manufacturer’s shop is a hydraulic or hydrostatic test, (conducted according to the ASME Code Section I, PW-54), at a pressure of ____ times the design pressure.
A tube expander consists of three rollers mounted in a cage, which fits inside the tube end. A tapered mandrel or spindle fits between the rollers and when the mandrel is turned, the rollers are rotated and forced out against the tube wall pressing in against the tube hole.
Boiler tubes are sometimes welded to _____, which have already been welded to the headers or drum.
Nozzles and stubs for connecting the drum to tubes and piping are formed by hot forging from a solid steel cylinder, or ______.
Handholes and manholes are provided in drums and ________ to give access to allow for cleaning, inspection, and repair during the life of the boiler.
The ASME Code Section __ specifies that the size of an elliptical manhole shall not be less than 280 mm by 380 mm or 250 mm by 410 mm.
Drum manhole openings may be elliptical or _____.
The ASME Code specifies that circular manholes must not be less than ____, inside diameter.
When a manhole opening is made in a drum or shell, the area becomes _______ due to the amount of metal removed.
The covers fit on the ______ of the drum and are held in place by means of bolts and yoke pieces.
The gaskets used are the woven type for pressures up to _____ kPa and the metallic type for higher pressures.
For pressures up to ______ kPa and temperatures up to 454°C, handhole covers with gaskets are used and are bolted into place.
Before the refractory and casing can be installed the ____ witnesses the hydrostatic test and carries out an inspection of the boiler.
(B) Boiler Inspector
Only some of the firetubes in firetube boilers are:
E. seal welded
________ boilers must be built or put together in the field (field erected).
Large quantities of ______ are used to complete the foundations, which must support the loads from the boiler and all of the auxiliary equipment.
The _________ steel carries the weight of the steam drum and the major pressure components.
The steam drum is usually the _______ major pressure component placed in the steel structure.
Coal pulverizers must be installed _____ to allow installation of coal piping to the boiler.