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BOILER

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Originally appearing in Volume V04, Page 153 of the 1911 Encyclopedia Britannica.

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BOILER MAKING The practice of the boiler, See also:

BRIDGE

bridge and girder shops may hereflues, &c., but is scarcely represented in bridge and girder See also:

WORK

work. Plates are See also:

bent to cylindrical shapes in boilermaking, for shells and furnaces, but not in girder work. See also:

WELDING (i.e. the action of the verb " to weld," the same word as " to well," to boil or spring up, the history of the word being to boil, to heat to a high degree, to beat heated iron; according to Skeat, who points out that in Swedish the compound verb

Welding is much more See also:

COMMON

common in the first than in the second, See also:

FURNACE

furnace flues being always welded and stand pipes frequently. In boiler work holes are generally drilled through the seams of adjacent plates. In bridge work each See also:

PLATE

plate or See also:

bar is usually drilled or punched apart from its See also:

FELLOWS, SIR CHARLES (1799-1860)

fellows. Boilers, again, being subject to high temperatures and pressures, must be constructed with provisions to ensure some See also:

ELASTICITY

elasticity and freedom of See also:

MOVEMENT

movement under varying temperatures to prevent fractures or grooving, and must be made of materials that combine high ductility with strength when heated to furnace temperatures. Flanging of certain parts, judicious staying, See also:

LIMITATION, STATUTES OF

limitation of the length of the tubes, the forms of which are inherently weak, provide for the first; the selection of See also:

STEEL, FLORA ANNIE (1847– )

steel or See also:

IRON [symbol Fe, atomic weight 55.85 (0=16)]

iron of high percentage See also:

ELONGATION

elongation, and the See also:

IMPOSITION (from Lat. imponere, to place or lay upon)

imposition of See also:

TEMPER (from Lat. temperare, to mingle or compound in due proportion, to qualify, rule, regulate, to be moderate, formed from tempos, time, fit or due season)

temper, or bending tests, both hot and See also:

COLD (in O. Eng. cald and ceald, a word coming ultimately from a root cognate with the Lat. gelu, gelidus, and common in the Teutonic languages, which usually have two distinct forms for the substantive and the adjective, cf. Ger. Kolte, kalt, Dutch koude

cold, provide for the second. The following are the leading features of See also:

PRESENT

present-See also:

day methods. It might be hastily supposed that, because plates, angles, See also:

TEES

tees, channels and See also:

JOIST

joist sections are rolled ready for use, little work could be See also:

LEFT

left for the plater and boilermaker. But actually so much is involved that subdivisions of tasks are numerous; the operations of templet-making, See also:

ROLLING

rolling, planing, punching and shearing, bending,quent stress, with liability to produce fracture. But it has been found that, when a shorn edge is planed and a punched hole enlarged by reamering, no harm results, provided not less than about -iis in. is removed. A See also:

GREAT

great advance was therefore made when specifications first insisted on the removal of the rough edges before the parts were See also:

UNITED

united.

In the work of riveting another evil See also:

long existed. When holes are punched it is practically impossible to ensure the exact coincidence of holes in different plates which have to be brought together for the purpose of riveting. From this followed the use of the See also:

DRIFT (from "drive ")

drift,—a tapered See also:

rod driven forcibly by See also:

HAMMER, FRIEDRICH JULIUS (1810-1862)

hammer blows through correspond- Fic. 2o.-See also:

THORNYCROFT, WILLIAM HAMO (1850- )

Thornycroft-Schulz See also:

WATER

Water-See also:

TUBE (Lat. tuba)

tube Boiler. welding and See also:

FORGING

forging, flanging, drilling, riveting, caulking, and tubing require the labours of several See also:

groups of See also:

machine attendants, and of gangs of unskilled labourers or helpers. Some operations also have to be done at a red or See also:

white See also:

HEAT (0. E. haktu, which like " hot," Old Eng. hat, is from the Teutonic type haita, hit, to be hot; cf. Ger. hitze, heiss; Dutch, hitte, heet, &c.)

heat, others cold. To the first belong flanging and welding, to the latter generally all the other operations. See also:

HEATING

Heating is necessary for the rolling of tubes of small See also:

DIAMETER (from the Cr. &a, through, µErpov, measure)

diameter; bending is done cold or hot according to circumstances. The fact that some kinds of treatment, as shearing and punching, flanging and bending, are of a very violent See also:

CHARACTER (Gr. xapareri7p, from xap&crew, to scratch)

character explains why practice has changed radically in regard to the method of performing these operations in cases where safety is a See also:

CARDINAL (Lat. cardinalis)

cardinal See also:

MATTER

matter. Shearing and punching are both severely detrusive operations performed on cold See also:

metal; both leave jagged edges and, as experience has proved, very See also:

minute cracks, the tendency of which is to extend under subse-See also:

ing holes in adjacent plates, by which violent treatment the holes were forcibly See also:

DRAWN

drawn into See also:

ALIGNMENT (from Fr. d and ligne, the Lat. Linea, a line)

alignment. This drifting stressed the plates, setting up permanent strains and enlarging incipient cracks, and many boiler explosions have been clearly traceable to the abuse of this See also:

TOOL (0. Eng. tdl, generally referred to a root seen in the Goth. taujan, to make, or in the English word " taw," to work or dress leather)

tool. Then, next, specifications insisted that all holes should be enlarged by reamering after the plates were in See also:

PLACE (through Fr. from Lat. platea, street; Gr. IrAar6s, wide)

place.

But even that did not prove a safeguard, because it often happened that the metal reamered was nearly all removed from one See also:

side of a hole, so leaving the other side just as the See also:

PUNCH

punch had torn it. Ultimately came the era of drilling See also:

RIVET (0. Fr. rivet, from river, to fix, fasten together, of unknown origin; Skeat compares Icel. rifa, to stitch together)

rivet-holes, to which there is no exception now in high-class boiler work. For See also:

AVERAGE

average girder and bridge work the practice of punching and reamering is still in use, because the conditions of service are not so severe as are those in See also:

steam boilers. Flanging signifies the turning or bending over of the edges of a plate to afford a means of See also:

union to other plates. Examples occur in the back end-plates of See also:

LANCASHIRE

Lancashire and Cornish boilers, the front and back plates of marine boilers, the See also:

FIRE (in O. Eng. f j'r; the word is common to West German languages, cf. Dutch vuur, Ger. Feuer; the pre-Teutonic form is seen in Sanskrit pu, pavaka, and Gr. irup; the ultimate origin is usually taken to be a root meaning to purify, cf. Lat. purus)

fire-boxes of See also:

LOCOMOTIVE

locomotive boilers, the crowns of See also:

VERTICAL (from Lat. vertex, highest point)

vertical boilers, the ends of conical See also:

CROSS

cross-tubes, and the See also:

Adamson seams of furnace flues. This practice has superseded the older See also:

SYSTEM

system of effecting union by means of rings forming two sides of a rectangular See also:

section (See also:

ANGLE (from the Lat. angulus, a corner, a diminutive, of which the primitive form, angus, does not occur in Latin; cognate are the Lat. angere, to compress into a bend or to strangle, and the Gr. ayKOS, a bend; both connected with the Aryan root ank-, to

angle iron rings). These were a fruitful source of grooving and explosions in steam. boilers, because their See also:

sharp angular See also:

FORM (Lat. forma)

form lacked elasticity; hence the See also:

REASON (Lat. ratio, through French raison)

reason for the substitution of a flange turned with a large See also:

RADIUS

radius, which afforded the elasticity necessary to counteract the effects of changes in temperature. In girder work where such conditions do not exist, the method of union with angles is of course retained. In the See also:

early days of flanging the See also:

PROCESS

process was performed in detail by a skilled workman (the angle ironsmith), and it is still so done in small establishments. A length of edge of about to in. or a See also:

FOOT

foot is heated, and bent by hammering around the edge of a See also:

block of iron of suitable shape. Then another " heat " is taken and flanged, and another, until the work is See also:

COMPLETE

complete. But in See also:

MODERN

modern boiler shops little See also:

hand work is ever done; instead, plates 4 ft., 6 ft., or 8 ft. in diameter, and fire-See also:

box plates for locomotive boilers, have their entire flanges bent at a single squeeze between massive See also:

DIES, CHRISTOPH ALBERT (1755-1822)

dies in a See also:

HYDRAULIC

hydraulic See also:

PRESS (through Fr. presse from Lat. pressare, frequentative of premere, to crush, squeeze, press)

press.

In the See also:

case of the ends of marine boilers which are too large for such treatment, a See also:

SPECIAL

special form of press bends the edges over in successive heats. The flanges of Adamson seams are rolled over in a special machine. A length of flue is rotated on a table, while the flange is turned over within a minute between revolving rollers. There is another See also:

ADVANTAGE

advantage in the See also:

ADOPTION (Lat. adoptio, for adoptalio, from adoptare, to choose for oneself)

adoption of machine-flanging, besides the enormous saving of See also:

time, namely, that the material suffers far less injury than it does in hand-flanging. These See also:

DIFFERENCES, CALCULUS OF (Theory of Finite Differences)

differences in practice would not have assumed such magnitude but for the introduction of mild steel in place of malleable iron. Iron suffers less from overheating and irregular heating than does steel. Steel possesses higher ductility, but it is also more liable to develop cracks if subjected to improper treatment. All this and much more is See also:

WRIT (O. Eng. gewrit, writ, from writan, to write)

writ large in the early testing of steel, and is reflected in present-day practice. A feature See also:

PECULIAR

peculiar to the boiler and plating shops is the enormous number of rivet holes which have to be made, and of rivets to be inserted. These requirements are reflected in machine See also:

DESIGN (Fr. desiin, drawing; Lat. designare, to mark out)

design. To punch or See also:

DRILL

drill holes singly is too slow a process in the best practice, and so See also:

MACHINES

machines are made for producing many holes simultaneously. Besides this, the different sections of boilers are drilled in machines of different types, some for shells, some for furnaces, some peculiar to the shells or furnaces of one type of boilers, others to those of another type only.

And generally now these machines not only drill, but can also be adjusted to drill to exact See also:

pitch, the See also:

NECESSITY (Lat. necessitas)

necessity thus being avoided of marking out the holes as guides to the drills. Hand-riveting has mostly been displaced by hydraulic and pneumatic machines, with resulting great saving in cost,. and the advantage of more trustworthy and See also:

UNIFORM

uniform results. For boiler work, machines are mostly of fixed type; for bridge and girder work they are portable, being slung from chains and provided with pressure water or compressed See also:

air by systems of flexible pipes. Welding fills a large place in boiler work, but it is that of the edges of plates chiefly, predominating over that of th'e bars and rods of the smithy. The edges to be united are thin and long, so that See also:

SHORT, FRANCIS JOB (1857– )

short lengths have to be done in See also:

SUCCESSION (Lat. successio, from succedere, to follow after)

succession at successive " heats." Much of this is hand work, and " gluts " or insertion pieces are generally preferred to overlapping See also:

JOINTS

joints. But in large shops, steam-driven See also:

POWER [WILLIAM GRATTAN] TYRONE (1797-1841)

power hammers are used for closing the welds. Parts that are commonly welded are the furnace flues, the conical cross-tubes and angle rings. Another aspect of the work of these departments is the immense proportions of the modern machine tools used. This development rs due in great degree to the substitution of steel for iron. The steel See also:

shell-plates of the largest boilers are i? in. thick, and these have to be bent into cylindrical forms. In the old days of iron boilers the capacity of rolls never exceeded about 4 in. plate. Often, alternatively to rolling, these thick plates are bent by squeezing them in successive sections between huge blocks operated by hydraulic pressure acting on toggle levers.

And other machines besides the rolls are made more massive than formerly to See also:

DEAL

deal with the immense plates of modern marine boilers. The boiler and plating shops have been affected by the See also:

general tendency to specialize manufactures. Firms have fallen into the practice of restricting their range of product, with increase in See also:

VOLUME

volume. The time has gone past when a single See also:

SHOP

shop could turn out several classes of boilers, and undertake any bridge and girder work as well. One reason is to be found in the diminution of hand work and the growth of the machine tool. Almost every distinct operation on every section of a boiler or bridge may now be accomplished by one of several highly specialized machines. Repetitive operations are provided for thus, and by a system of templeting. If twenty or fifty similar boilers are made in a See also:

YEAR

year, each plate, hole, flange or stay will be exactly like every similar one in the set. Dimensions of plates will be marked from a See also:

SAMPLE (through the O. Fr. essemple, from Lat. exemplum; a doublet of " example ")

sample or templet plate, and holes will be marked similarly; or in many cases they are not marked at all, but pitched and drilled at once by self-acting mechanism embodied in drilling machines specially designed for, one set ofoperations on one See also:

KIND (O. E. ge-cynde, from the same root as is seen in " kin," supra)

kind of plate. Hundreds of bracing bars for See also:

bridges and girders will be cut off all alike, and drilled or punched from a templet bar, so that they are ready to take their place in bridge or girder without any adjustments or fitting. (J. G.

End of Article: BOILER

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