Stack (boiler)

“ In localities where the water is bad, the water jacket will require extra attention, as it gets as badly scaled like steam boilers, principally due to a very slow or retarded circulation, which allows the sediment to settle, and should the water supply be shut off, even for a few minutes, the cylinder heat will bake it so hard as to give considerable trouble. It is a good plan to put a good boiler compound in the water jacket, and run the machine for some time without any circulation. ”

“ In practice, water will speedily be carried over by the loop and accumulate in the drop leg until it rises to the level b, which would balance the difference in pressure. As the loop will still continue to bring over water, it follows that as fast as a slug or piston of water is deposited by the steam on the top of the column at b, it overbalances the equilibrium and an equal amount of water is discharged from the bottom of the column through the check valve into the boiler. ”

“ Being a slim lad, one of my duties was to creep into the boilers through the manhole, which was just large enough to let me through; and with a hammer and a sharp-linked chain I must "scale" the boilers by pounding on the two large flues and the sides with the hammer, and sawing the chain around the flues until all the accumulated mud and sediment was loosened. It was then washed out by streams from the deck-hose, the force-pump being manned by the firemen, of whom there were eight on our four-boiler boat. ”

“ No braces or stays employed in the construction of marine boilers shall be allowed a greater strain than six thousand pounds per square inch of section, and no screw stay bolt shall be allowed to be used in the construction of marine boilers in which salt water is used to generate steam, unless said stay bolt is protected by a socket. But such screw stay bolts, without sockets, may be used in staying the fire boxes and furnaces of such boiler, and not elsewhere, when fresh water is used for generating steam in said boiler. Water used from a surface condenser shall be deemed fresh water. ”

“ If he complains that the steamer trembles in all her timbers, and the steam, as it escapes at the calling-places, makes a horrible noise, agree with him at once, hinting that an explosion of the boiler is by no means an unlikely event through the carelessness of the coal-begrimed stoker, who is just then cooling himself at an open air-hole, and wiping his brow with a wisp of tow. ”

“ A.--The blow-off cocks of a boiler are generally placed some distance from the boiler; but it appears preferable that they should be placed quite close to it, as there are no means of shutting off the water from the pipe between the blow-off cock and the boiler, should fracture or leakage there arise. Every boiler must be furnished with a blow-off cock of its own, independently of the main blow-off cocks on the ship's sides, so that the boilers may be blown off separately, and may be shut off from one another. ”

“ They are rarely made with bottoms, or with stuffing boxes, and are consequently, for the most part, adorned with stalactites of salt after a short period of service. The water discharged from them, too, from the want of a proper conduit, disfigures the front of the boiler, and adds to the corrosion in the ash pits. It would be preferable to combine the gauge cocks appertaining to each boiler into a single upright tube, connected suitably with the boiler, and the water flowing from them could be directed downward into a funnel tube communicating with the bilge. ”

“ Smudges of dirt are not uncommon on a man’s face and hands, perhaps, but the begrimed Vulcans of the coal-burning ships have no counterpart on the oil burners, and the coal dust and the dingy stokehold is a far cry.
The Majestic’s boilers do not depend upon natural draft, but a set of four powerful fans draws the warm air from the turbine rooms through two great air shafts about seven feet in diameter and forces it under pressure beneath the boilers. These great air shafts total 1,000 feet in length, and a part of the air they supply is led to each boiler. ”

“ If the job is a large one, a pump may be employed to insure the proper circulation. After this the pipe sizes and connections can be worked out. The one great enemy of hot-water circulation is air. Therefore, no traps or air pockets should ever appear in the piping system. The boiler, as it is often referred to, is the hot-water storage tank. A copper or iron tank holding sufficient water to supply all fixtures, even when every fixture demands a supply at the same time, is installed in a convenient place and the heating arrangement connected with it. ”

“ In the working day not a moment is wasted. When the whistle blows the full working pressure is ready to begin work and maintain duty until night. There is no fluctuation of pressure due to careless boiler attendance; no wheeling coal or water barrels to keep pace with advancing channelers. Some of the old boilers, discarded from steam service, are used as air receivers, these and other reservoirs, together with the pipe line itself, unite their immense storage capacity so that throughout the day there is no peak load. ”

“ Draught.—In most boilers the draught necessary for combustion is “natural,” i.e. produced by a chimney. For marine purposes, although “natural” draught is the more common, many boiler installations are fitted with “forced” draught arrangements. Two distinct systems are used. In that known as the “closed stokehold” the stokehold compartment of the vessel is so closed that the only exit for air from it is through the fires. ”

“ It is advisable occasionally—say once a month—in towns where fires are not frequent, to fire up and take the engine out for practice and drill, and to make sure that it is in proper working order, after which the boiler should be blown off and refilled with fresh water, as hereinafter directed.
Every engine required to pump salt water, or other water unfit for the boiler supply, should be provided with a fresh-water feed tank. ”

“ Never use a valve in putting in a low pressure apparatus if it is possible to get along without it. All the valves or cocks that are actually required in a well-proportioned low pressure apparatus are, a cock to blow off the water and clean out the return pipes, another to turn on the feed water. Of course the safety valves, gauge cocks, and those to shut fire regulators and such as are a part of the boiler, are not included in this “point.” ”

“ Answer.—It is often done by old stokers as well as new ones, and is more of a silly habit than of [24] trying the pressure of the steam, especially as there is nowadays a pressure gauge for every boiler in a stoke-hold. By lifting the safety-valve while steam is in the boiler and dropping it down again is a dangerous practice ”

“ When starting fires close the gauge cocks and safety valve as soon as steam begins to form.
Go slow. It is necessary to start all new boilers very slowly. The change from hot to cold is an immense one in its effects on the contraction and expansion of the boiler, the change of dimension by expansion is a force of the greatest magnitude and cannot be over-estimated. ”

“ These devices for the stilling of the water and collection of the sediment are made in various forms and all sizes and capacities, and are located at the sides or back of the boiler setting and even on top of the boiler. There is a system where pipes in a coil are fixed in the sides of the furnace and exposed to its greatest heat, and which, owing to their enlarged area, act as most efficient reservoirs. In all these devices there is an upflow pipe connected with the lower and coolest water, and a return pipe connecting with the top of the water where it is hottest. ”

“ As the outside shell and front plate are 11⁄2 inch thick and are not exposed to any wear at all, these boilers are sufficiently strong. A duplicate front plate with set of tubes attached is always kept on hand in case of need. Another form of cast-iron boiler is shown in Fig. 9., made in several parts put together with flange joints, with an internal fireplace and flue also made of cast iron. When cast iron was used for the parts exposed to the fire in boilers intended for high pressure, it was sometimes employed in the form of tubes of small diameter and proportionately thinner ”

“ The heads of two of the boilers are to be seen on the left of the view. They are called the starboard and larboard boilers—those words meaning right and left. That is, the one on the right to a person standing before them in the engine room, and facing them, is the starboard, and the other the larboard boiler. It is the larboard boiler which is nearest the spectator in the engraving.
The boilers, the heads of which only are seen in the engraving, are enormous in magnitude and capacity, extending as they do far forward into the hold of the ship. ”

“ I had reflected a good deal on the observation shown to me by the engineer at Willimantic, and had felt that tubular boilers needed a better vertical circulation. This was limited by the small space left for the descending currents, the sides being filled with tubes almost touching the shell. So I allowed a space five inches wide between the shell of the boiler on the sides and bottom and the nearest tubes, as it was evident to me that the water, filled with bubbles of steam, would rush up among the tubes fast enough if the comparatively solid water at the sides could only get down. ”

“ All the inside and outside surfaces should be kept clean to avoid waste of fuel; to aid in this service the best forms are provided with extra facilities for cleaning. For inspection, remove the hand holes at both ends of the tubes, and by holding a lamp at one end and looking in at the other the condition of the surface can be freely seen. Push the scraper through the tube to remove sediment, or if the scale is hard, use the chipping scraper made for that purpose.
Hand holes should be frequently removed and surfaces examined, particularly in case of a new boiler. ”

“ Should the water being delivered by the main pumps be unsuitable for feeding the boiler, this valve must remain closed, and a supply from a barrel or tank introduced through the connection provided for that purpose.
When feeding the boiler, it is a good plan to occasionally feel the pipe leading from check to boiler with the hand, as one can tell by this means whether the pump is feeding properly. If feeding all right, the pipe will be cool. If the pipe is hot, the pump is not feeding properly, try the pet cock.
Always keep a good torch, ready for use, in the fuel pan. ”

“ For the shell plates and for long stays, a quality having a tensile strength ranging from 28 to 32 tons per sq. in. is usually employed, and for furnaces and flues, for plates which have to be flanged, and for short-screwed stays, a somewhat softer steel with a strength ranging from 26 to 30 tons per sq. in. is used. The tubes of ordinary land and marine boilers are usually made of lap-welded wrought iron. In water-tube boilers for naval purposes seamless steel tubes are invariably used. ”

“ To avoid these conditions, the piping should be of brass or lead and the storage tank should be of copper. The installation cost of brass and copper is greater than steel, but they will not have to be replaced in two or three years, as is the case with other material. A valve should be placed on the cold-water supply to control the entire hot-water piping system. A pipe with a stop cock should be placed underneath the boiler and should extend [129] into a sink in the basement so that the boiler can be drained at any time for cleaning or repairs. ”

“ The lower boxes of the economizer elements are connected to a horizontal feed pipe which is kept supplied with water by a feed-pumping engine, and the upper boxes are connected to another horizontal pipe from which the heated feed-water is taken into the steam-chest. Both the boiler proper and the economizer are enclosed in a casing which is formed of two thicknesses of thin iron separated by non-conducting material and lined with firebrick at the part between the fire-bar level and the lower rows of tubes. ”

“ The large mass of water heated to the evaporating point, the heated brickwork of the flues, and the large fireplace, are so many assistances to regularity, and enable the man in charge to attend to his other duties without the risk of spoiling the boiler or letting down the steam by a few minutes' absence from the stoke hole. Steam employers are found at present to prefer the known dangers of the large boilers to the supposed safety of small boilers, which they fear are troublesome in practice. ”

“ Boilers are fitted with dry and wet uptakes, which differ from each other as follows:—The dry uptake is wholly outside the boiler, and consists of an external casing bolted on to the firing end of the boiler, covering the tubes and forming the smoke-box, and is fitted with suitable tube doors. A wet uptake is carried back from the firing ends of the boiler into its steam space, and is wholly surrounded by water and steam. The dry uptake seldom requires serious repair ”

“ This wheel should be a lead casting, and as heavy as possible. A heavy flywheel contributes much to the operating efficiency of the engine. The propeller-shaft and crank are shown at N in the insert.
The boiler is made from a strong tin can about 13/4 inches in diameter and 41/2 inches long. It is cleaned inside and out, and all [85] the seams are double-soldered. The lid is also soldered on the can. This little boiler, although not elaborately made, will be found capable of standing up under considerable steam-pressure, and so no fear need be had of accidents by explosion. ”