Steam pipe

“ The steam generated in the boilers is conveyed to the engine, where it is to do its work, by what is called the steam pipe. The steam pipe of the larboard engine, that is, of the one nearest the spectator, is not represented in the engraving, [Pg 725] as it would have intercepted too much the view of the other parts. That belonging to the starboard engine, however, may be seen passing across from the boiler to the engine, on the back side of the room. The destination of the steam is the cylinder. ”

“ The object of a steam trap is for the removal of water of condensation without allowing the escape of steam from drying apparatus and steam pipes used for heating, power, or other purposes. One of the plans employed is by an expansion pipe having a valve fixed to its end, so that when the pipe shortens from being cooler, due to the presence of the water, the valve opens and allows the escape of the water until the steam comes to the trap, which, being hotter, lengthens the pipe and closes the valve. ”

“ It is bad practice to support the main steam pipes over boilers by hangers from the building as the building may settle in a different degree from the boiler hence the steam pipes are not properly supported, i.e., they are either strained unnecessarily by the strain upon the hangers or they are permitted to support themselves; it is better to support them by iron props underneath, made by screwing a flange upon the end of a piece of pipe of proper length and having a wrought iron crotch with thread and nut for adjustment inserted in the upper end. ”

“ A.--Most of the pipes of marine engines should be made of copper. The steam pipes may be of cast iron, if made very strong, but the waste water pipes should be of copper. Cast iron blow-off pipes have in some cases been employed, but they are liable to fracture, and are dangerous. The blow-off and feed pipes should be of copper, but the waste steam pipe may be of galvanized iron. Every pipe passing through the ship's side, and every pipe fixed at both ends, and liable to be heated and cooled, should be furnished with a faucet or expansive joint ”

“ The steam pipe should be short to reduce the loss of heat between engine and boiler to a minimum, and both short and direct to avoid undue friction and consequent drop in pressure of the steam in passing through the pipe to the engine. ”

“ Radiator connections.—The connections from the risers to the radiators are always made somewhat larger in proportion than the mains and risers, and Table IV gives sizes which represent good practice for low-pressure systems.
Carpenter and Sickles' rule for steam pipe sizes.—In designing piping for large systems it must be borne in mind that there are many things which affect the flow of steam in a piping system, and special cases must have special consideration. Elbows, bends and valves greatly increase friction in the pipes. ”

“ Take steam from the highest part of the boiler. Do not connect steam pipe to a pipe furnishing steam for any other purpose; but if you have to take steam from a large steam pipe, tap it on the upper side so as to avoid the drip caused by condensation in the large pipe. When the boiler is some distance from the pulsometer the steam pipe to it should be larger than is needed at the pulsometer, and be protected by some non-conducting substance. Reduce to size required at the pulsometer and provide a pet cock to draw off condensed steam before starting it. ”

“ Each tube has a hard metal cap or steel head on the top, and below this an opening where the connection with the main steam pipe is made. The bottom of the tube is pointed so that it can be forced down into the ground. A man stands on a tall derrick and with a twelve-pound sledge hammer drives the pipe, inch by inch, through the earth. The steam-heated steel melts the ice as it goes down. When the point reaches bed-rock, it is left there for two or three days, oozing forth steam. To thaw out enough ground for the dredges to work on, hundreds of these steam points have to be sunk. ”

“ The slide valve is of brass, and the regulator consists of two brass slide valves worked over ports in a chest in the steam pipe, set in the smoke box. The steam pipe is of brass, No. 14. wire gauge, perforated within the boiler barrel with holes 1/12th of an inch in diameter along its upper side. The blast pipe, which is of copper, has an orifice of 4-1/4 inches diameter. There is a damper, formed like a Venetian blind, with the plates running athwartships at the end of the tubes. ”

“ The contrary end of this tube is joined to the steam pipe or boiler, where the Steam is always active; and by this means a constant supply of Steam is thrown into the space aforesaid, which Steam preserves the rod air tight: being kept as strong or stronger than the pressure of the outward air. Thus the steam here does the office of water, &c. on the piston of the Engine, when the packing becomes rather insufficient. ”

“ A high steam chest too, by rendering boiling over into the steam pipes, or priming as it is called, more difficult, obviates the necessity for so large a steam space; as does also a perforated steam pipe stretching through the length of the boiler, so as not to take the steam from one place. The use of steam of a high pressure, worked expansively, has the same operation ”

“ The boilers at Johnstown were located over the heating furnaces, utilizing their waste heat, and were scattered all over the works. The largest steam-pipes were 8 inches in diameter. I gave them [272] an order to make a steam-receiver 5 feet in diameter and 15 feet high, to be set close to the cylinder of the engine. They made it 18 feet high, the width of the sheets favoring this greater height. I took the steam by an 8-inch pipe entering at the top of this receiver and extending down 12 feet; from the top of the receiver I took the steam over to the engine by a 12-inch pipe. ”

“ Never forget to allow for expansion when running long lines of steam pipe, whether for heating or power, as the neglect of this precaution leads to the formation of immense crooks or bends in the line of pipe wonderful to behold. There must be a slip joint somewhere in long lines of steam piping, unless expansion is allowed for.
Valves stick on their seats because they are frequently shut when cold, and when heated by the steam the valve stem becomes lengthened, and presses the valve hard into the seat. [Pg 178]
Geiser Traction Engine—Right Side. ”

“ The benefits of covering steam-pipes to prevent radiation are strikingly illustrated by the following example: The Thomson-Houston electric-light plant in Ann Arbor has about 60 feet of seven-inch pipe connecting the boilers with the engines and two large steam-drums above the boilers: in March, 1887, the steam at the far end of this pipe was tested to determine the amount of entrained water, the pipes and drums at the time being uncovered. An average of nine experiments gave 31.01 per cent moisture. ”

“ Seeing that the tube or pipe is capable of withstanding all the pressure that the steam can give, it is difficult to account for the tremendous repelling force, which is, undoubtedly, brought into operation in explosions or ruptures of steam pipes carrying what are now comparatively low pressures. ”

“ Fig. 655 shows a bracket with one adjustable roll designed for main steam pipes. This is an elaborate device but would be appreciated in buildings where everything is wanted to make up a strictly first class line of details.
Fig. 657 represents an extension of the same idea in which one bracket is made to carry two lines of pipe smaller than the one shown in the preceding illustration. Fig. 656 is a support made of one inch round iron and answers every purpose where all of these designs of pipe hangers permit of free expansion and contraction of the pipes. ”

“ Entirely too little attention is given to this matter on the part of designers and it cannot be too strongly emphasized that, for economy, the steam pipe between an engine and boiler should be as short and direct as possible, having regard of course, for proper piping methods. ”

“ The American Society of Mechanical Engineers recommends a sampling nozzle made of one-half inch iron pipe closed at the inner end and the interior portion perforated with not less than twenty one-eighth inch holes equally distributed from end to end and preferably drilled in irregular or spiral rows, with the first hole not less than one-half inch from the wall of the pipe. Many engineers object to the use of a perforated sampling nipple because it ordinarily indicates a higher percentage of moisture than is actually present in the steam. ”

“ This, although not a boiler fixture or fitting, is intimately connected with them: it is an appliance fast coming into use both for land and marine engines, to guard against the danger to steam engine cylinders arising from “the priming” of the boilers when the steam is used at a high pressure with high speed of the piston.
The separator is usually placed in the engine room, so as to be well in sight. The steam is led down the pipe round a diaphragm plate and then up again to the engine steam pipe. ”

“ The action is particularly severe if steam is admitted to a cold pipe containing water, as the water may then form a partial vacuum by condensing the steam and be projected at a very high velocity through the pipes producing a characteristic sharp metallic knock which often causes bursting of the pipe or fittings. The amount of water present through condensation may be appreciated when it is considered that uncovered 6-inch pipe 150 feet long carrying 3600 pounds of high pressure steam per hour will condense approximately 6 per cent of the total steam carried through radiation. ”

“ That form has descended to all modern piping for water, steam, and gas, because the best that a pipe can take. No other shape has, proportionately to capacity, so little surface for friction inside or rust outside. A locking-bar water pipe, devised by Mephan Ferguson, of Perth, Australia, is made of two plates of equal width, curved into semi-circles which are pressed at their ends into channel bars of [46] soft steel. As the locking-bars and joints are opposite each other, their joints can be tightly closed by a simple machine which exerts pressure in a straight line. ”

“ Fig. 655.
Fig. 656.
Fig. 657.
Steam Pipe Lines. These are constructed of cast iron or wrought iron and used for conveying a supply of steam from the boilers to engines, pumps, turbines and other machines driven by steam. Usually these lines are built up with straight pipe and “fittings.” The names of the latter are as follows: elbows; forty-fives (45°) ; tees; plugs; caps; reducers (or bushings) ; nipples; valves; unions (with ground, perishable, and flange joints) ; couplings (reducing and right and left) ; crosses ”

“ The length of the pipe, to which the branches are fixed horizontally, is about 18 feet to the nosle of the bellows: notwithstanding which length, the steam, that passed thro' the pipe into the bellows, was so hot before the water boiled, as to force thro' the leather: but this I easily remedied, by fixing a brass cock of one inch and a half diameter to the pipe, which hindered the steam from ascending, until the engine was ready to work; and being opened, the air continually keeps it cold until the engine has done working ”

“ The fire is then to be lighted beneath the larger boiler, to make the water boil, by which means the steam being confined, will be greatly compressed, and will, therefore, on opening a way for it to issue out (which is done by pushing the handle of a regulator from the operator) , rush with great violence through a steam-pipe into a receiver, driving out all the air before it, sending it up into a force-pipe through a clack, as may be perceived from its noise; when the air is expelled, the receiver will be very much heated by the steam. ”

“ All the metals used in the construction of marine engines expand by heat, and this is allowed for in adjusting the lengths of the eccentric rods, or of the valve spindles when setting the valve lead. In the case of two marine boilers being connected together, the steam pipe is fitted with an expansion joint, one pipe end having an enlarged bore to receive the other. The joint is made by packing, which is squeezed up by a gland, whose bore fits on the outside of the pipe which moves through the gland bore, from the expansion and contraction. ”

“ Before connecting the steam pipes, blow out with steam pressure the chips and dirt in the steam pipes. Always use the union furnished with the pump. It has a gauze gasket in it to catch the dirt that may get into the valve. Before starting pump, open air cock in delivery pipe and turn exhaust lever back, away from the air chamber. Then open throttle valve wide and allow pump to exhaust into the air until it takes suction, when deflecting lever may be thrown forward toward air chamber and cold water in the pump will condense the exhaust and return it to the boiler. ”

“ So paradoxical and inoperative did this seem at first that it was met with incredulity, and not until repeated demonstrations established the fact was it accepted as an operative device. Its construction is shown in Fig. 82. A is a steam pipe communicating with the boiler, B another pipe receiving steam from A through small holes and terminating in a cone. C is a screw rod, cone-shaped at its extremity, turned by the crank M, and serving to regulate and even intercept the passage of steam. D is a water suction pipe. ”