Tube (machinery)

“ Seamless tubes, which are stronger than those just described, are made by drawing a bloom of the metal perforated by an axial hole or provided with a core of some refractory material, or, in certain cases, by forcing the plastic metal by hydraulic pressure through an appropriate die. The seamless steel tube industry is now of great dimensions owing to the development of steam engineering. Another type of seamless tube is the cast-iron tube, usually of large diameter and employed for gas and water mains ”

“ If a tumbler, electrified in this way, be inverted over pith balls, instead of brass-filings, the balls will leap with surprising velocity up the sides of it.
The luminous Discharging-rod. Provide a glass tube in the shape of a common discharging-rod, about ten inches in length, and let the bore of the tube be nearly the eighth of an inch in diameter; upon one end fasten with cement, or otherwise, a brass knob, so as to be perfectly air tight. Now expel the air from the tube, by heat or the air pump, and then fix another knob upon the open end, in a way similar to the former. ”

“ Experience shows that, where great exactness of manipulation cannot be obtained, it is necessary to allow only one train in each section of a tube, whether worked by vacuum or pressure. But where there is no intermediate station, and where the tube can be carefully worked, carriers may be allowed to follow one another at short intervals in a tube worked by vacuum, although it is not perfectly safe to do so in one worked by pressure. ”

“ The tube is thus slowly drawn through the hole in the die. As these dies are of very hard material, either hard cast iron or hardened steel with hole a little smaller than outside of the tube, they compress the tube upon the mandrel inside and the thickness of wall is thus regulated, the excess metal being squeezed out so that the tube is very materially lengthened. Tallow or grease with the lime-coat lubricate the tube, a little being continually drawn into and through the somewhat funnel-shaped die. ”

“ In order to reduce the strength of the current a piece of brass tubing, F, is pushed into the space, C, surrounding the core, or if no brass tubing of the required size is on hand, roll a paper tube, cover with 4 or 5 thicknesses of tinfoil and then wrap with more paper, using glue to hold the tinfoil in place and to keep the tube from unwinding. When the tube is pushed all the way in, the current produced will be almost unnoticeable, but when it is withdrawn the current will be so strong that a person cannot let go the handles until the coil is shut off. ”

“ This plan of keeping open the passage in a tube likely to be blocked by sudden bending, has been imitated by mankind, in making rubber gas tubing, for example. As a plain rubber tube is easily bent, the gas would be in constant danger of being cut off. To prevent this, Nature's patent is usually imitated, and a coil of wire is placed along the inside of the tube. Thus, a sharp bend, such as would instantly obstruct the passage of the gas, is prevented. ”

“ The tube is a mere hair-like hollow filament of glass, and the ink, which would not itself flow from a tube of so fine a bore, is squirted out by electrical repulsion when the insulated reservoir in which it is contained is electrified at the receiving station by an ordinary machine. ”

“ Boiler tubes are secured in their tube plates by being expanded in. This may be done by driving in a taper steel mandrel, and then clinching them over, or by using a tube expander. There are two principal kinds of tube expanders, in one of which small rolls travel around the bore of the tube and expand it, while in the other a number of segments, held together by a spring, are forced outwards by a mandrel driven in by hammer blows.
Too much expanding is apt to weaken the tube close to the inside face of the tube sheet. ”

“ Take a tube which is very regular, and about one-eighth or one-twelfth of an inch diameter in the bore; solder a reservoir at each end, one of them much larger than the other; make a bend near the large reservoir, and then fill the instrument with alcohol to A. Above that, place the first index, which consists of a very small piece of tube closed at one end and cut off square at the other. In the interior of this tube the two ends of a hair are fixed, by means of a little rod of iron, which is pushed into the tube. ”

“ An iron rod, screwed into a stand or base, and conical at the top, passes up through the tube and supports the whole upon its point. To stiffen the arrangement, three bent strips of tin are fastened to the top of the tube and to the inner rim, as shown in the woodcut, where the middle strip conceals the central tube. There is room inside the circle of test-bottles to place the other bits of apparatus when not in use. ”

“ These must make so good a fit that when slightly lubricated they shall prevent the passage of air between them and yet set up very little friction. If you cannot find a piece of steel rod and brass tubing which fit close enough naturally, the only alternative is to rub down a rod, slightly too big to start with, until it will just move freely in the tube. This is a somewhat tedious business, but emery cloth will do it. The rod should be 3-3/8 inches, the tube 2-1/8 inches, long. I used rod 3/16 inch in diameter; but a smaller rod would do equally well. ”

“ The sides, bottom, and top of these gigantic tubes are formed of oblong wrought iron plates, varying in length, width, and thickness, according to circumstances, but of amazing size and weight. They are so arranged as to obtain the greatest possible strength, the whole being riveted together in the strongest manner. In addition to the 1600 tons of wrought iron in each of the four large pieces, an additional 200 tons was used to form lifting frames, and cast iron beams for the purpose of attaching the tube to those huge chains by which they were elevated. ”

“ The outer tube may be 3/8ths of an inch thick, to afford stability to the working cylinder, the blowing cylinder, and the forcing pump fastened to this tube, and as an ultimate perfect barrier against explosion. The respective distances of the other tubes constituting the outside of the boiler, the condenser, and air-vessel, will be the same as hereinbefore given, and therefore their diameters will depend upon the diameter of the fire-place. The cap-piece in small engines may be half an inch thick, and in large engines an inch. ”

“ In this way it is possible to get a tight, smooth tube. Immediately withdraw the core, twisting it slightly in a reverse direction if it tends to stick. Before using the core again, make sure it is free from glue and regrease it. When a sufficient number of tubes have been made and hardened, neatly trim the ends off squarely, and then form an equal number of short tubes, about 2 in. long, by winding a strip of glued paper on a large wire nail until a diameter is reached that will fit snugly into the pipes already made. ”

“ You will also need some brass rod which will just slide into the tube tightly. Cut off two pieces of the brass rod each one and three-quarters inches long and slip these through the upper holes in the binding-posts and into the glass tube as shown in Figure 234. Before putting the second rod in place, however, you must put some nickel and silver filings in the tube, so that when the rods are pushed almost together, with only a distance of about one-sixteenth of an inch between them, the filings will about half fill the space. ”

“ When a carrier arrives, after passing the slots that allow the air-current to flow into the branch pipe, it compresses50 the air in front of it against the gate. This compression checks its momentum, and it comes gradually to rest. The air compressed between the carrier and the sluice-gate operates to move the piston slide-valve, thereby admitting air to the gate cylinder under the piston, which rises, carrying with it the sluice-gate. The tube is now open to the atmosphere, and there is just sufficient pressure in the tube to push the carrier out on to a table arranged to receive it. ”

“ The ends of the tube are closed by means of caps through which pass electrodes for making connections between the discs and exterior conductors. The steel tube, when necessary, is provided with ribs or fins for the dissipation of acquired heat. ”

“ Allen said to me that he had an idea that by inclining the tubes at a small angle from the vertical a better circulation would be got than in the Field tubes. He thought the steam as fast as formed would all go to the upper side of the inclined tubes, and would rush up along that surface without driving the water before it, and so the water would always be at the bottom of the tube, no matter how hard the boiler was fired. ”

“ It would be very difficult to bend iron tubes without involving great expense. The thickness of the bent portion of an eight-inch tube is usually three-sixteenths of an inch and never less than one-eighth of an inch. ”

“ A tube, therefore, of this kind is very convenient in some experiments, because we can, in effect, see the electric current passing through it. If I connect one end of this tube with the earth, and the other with the terminal of an electrical machine, and if then the handle of the electrical machine is turned, the tube will continue to glow as long as the electrical machine is rotated. The electrical machine must be regarded as a pump which is forcing something called electricity through the vacuum tube, and as long as the pressure is continued the current flows. ”

“ Cast-iron tubing may be driven hard with a monkey. To withdraw broken or defective tubing [75] quickly, two hooks attached to ropes are lowered down from opposite sides of the bore-hole, caught on the rim of the lowermost tube, and power applied to haul the tubing up bodily.
Figs. 87 to 91 show good methods of forming tube or pipe joints both in cast and wrought-iron, when not screwed. ”

“ It is practically a huge spinning with hot metal. After this single rolling process, the new formed tube is subjected to two drawings in a mandrel, in practically the same fashion that American tubing is treated, until it is reduced to the required diameter and gauge. ”

“ The outer extremity of the two tubes supports the platinum spiral, which is fixed to them very simply by the aid of two small brass needles of conical form, which pinch the wire in the tube and hold it in place. There is nothing easier to do than replace the wire. ”

“ In operating large tubes, that is to say, tubes six or eight inches in diameter, there is an advantage in using compressed, rather than exhausted air, in the construction of the sending and receiving apparatus, especially when the tubes are very long. With an ample supply of compressed air always at hand, the air-cushions can be made shorter and more effective in bringing the carriers quickly to rest.140 With exhausted air the cushions are ineffective, and consequently must be made very long in order to stop the carrier before it strikes the closed end of the tube. ”

“ Two immense tubes, lying side by side, each ten feet in diameter, made of a substance more durable than steel, form the road bed of this lightning system of travel. The cigar-shaped cars have hard rubber-wheels and fit over raised bars all around on the inside of the immense Tube. ”

“ In order to give some idea of the energy possessed by one of these carriers travelling at this speed, it may be said that if the end of the tube were left open and turned upward, an emerging carrier would rise about forty feet into the air. It is easy to imagine how apparatus, depending for its operation upon impact with a moving carrier, would be soon destroyed, as well as the carriers themselves. This is why receiving apparatus used with small tubes and light carriers cannot be applied to large tubes with heavy carriers. ”

“ And once a crowd is collected and its attention attracted to one spot, the capabilities of advertising the goods on sale are apparent.
A pasteboard or light wooden disk D, 3 feet in diameter or over, is mounted on a shaft, S, operated by an electric motor or such power as may be attainable. Upon its surface are mounted the tube-holders T T T T, connected, as shown, by wires leading from the secondary of the Ruhmkorff coil. Starting at the shaft S, the circuit runs to the first tube-holder, where the continuity of the wire is broken to allow of the attachment of the vacuum tube. ”

“ It consists of a glass cylinder, elongated into tubular form, and hermetically closed at the ends. When the tube is made, the air is exhausted as nearly as possible from it, and the ends are sealed over a vacuum as perfect as science is able to produce. Through the two ends, bits of platinum wire are passed at the time of sealing, so that they project a little within and without. The interior of the tube is thus a vacuum into which at the two ends platinum wires extend. Electrical communication with outside apparatus is thus supplied. ”

“ Weights for quickmatch may be made by nearly filling the brass tube with useless rusty old nails, tacks, screws, or odd bits of iron, or brass; then pouring in melted lead. If the ladle will not hold enough lead to fill it at once, it may be poured in at twice, thrice, four or more times. A tube 11⁄4 inch diameter and 6 inches long will weigh 21⁄2 lb. This will keep a great length of match tight and straight. Half-an-inch at each end of the tube should be solid lead, one to receive the screw, and one to make a firm bottom. ”

“ The most extensive use of small pneumatic tubes in this country has been in our large retail department stores for despatching cash to and from a centrally located cashier’s desk. Seamless brass tubes are usually used, and, since the tubes are short, the air is either compressed or exhausted by means of positive rotary blowers. At the outlying stations the tubes are usually open to the atmosphere, while at the central station simple forms of valves are used for sending and receiving. An outgoing and a return tube are always used, and the air is kept in constant circulation. ”