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disadvantages, corresponding to the conditions, the positions of the machines to be operated and the duty that is to be performed. Again, we may profitably make use of compressed air for some of our work, as for instance, for drawing patterns, turning flasks and other portions of the lighter work of the iron foundry, as well as for the chipping room where hand chipping tools so operated are very convenient and useful.

Hammers operated by compressed air may be used in the forge shop, since this force may be transmitted long distances with practically no loss such as steam is subjected to by condensation, and electricity by loss of electromotive force.

Various operations in the machine shop also may render a supply of compressed air very desirable. This matter will be governed to a considerable extent by the kind of work to be done, or kind of machinery to be built.

It would seem best in theory as well as practice, and most efficient and economical, to avail ourselves of whatever good points each method possesses for the particular case in question, and, by using any of the different systems where the conditions are most favorable for its employment, to make the most of the useful and practical features and avoid as many of the difficulties and disadvantages as we may be able.

For instance, while the practice of driving individual machines by separate motors may be said to be yet in its infancy, enough has been already done to prove its advisability in many ways, and to show that planers from 40 inches upwards may be profitably driven in this manner.

The same may be said of lathes from say 36 inches upwards, and also of the larger radial drills, vertical milling machines, boring mills, and, in fact, of most of the heavy machine shop tools. At the same time it does not appear to be as efficient or practical to apply individual motors to small machines when a group of them may be conveniently driven from a short line shaft run by one motor. The more recent improvements in motors, however, have adapted them to their economical use on much smaller machines even when a slow speed is required.

The question of friction of the two systems of transmitting power, that is, from the engine by shafting and belting, or the loss of power by generating an electric current with which to drive motors, is one which has provoked much discussion. Probably it will be found in practice to be about as follows: Where the distance is short, shafting and pulleys are much the more economical. For distances of two or three hundred feet there will be little difference in the two systems. For much greater distances the advantages are in favor of the electric method.

The plan of power transmission here selected is to drive from the balance wheel of the engine to a 72-inch pulley on the main line of shafting, giving a

shaft speed of 240 revolutions per minute. This shaft is in lengths of 20 feet, supported by hangers every 10 feet, and with a hanger on each side of main driving pulleys. The three lengths in the center are 5 inches in diameter and the remaining portion each way from these three lengths is 34 inches in diameter to the end.

Cut-off couplings are provided on the main shaft at the points shown in the drawings, for the purpose of stopping either section of the shaft in case of accident. In the same manner, the shaft in the gallery over the main line has a cut-off coupling at each end of the section, upon which the main pulley is located.

The smaller sizes of shafting are now usually made on the odd sixteenth of an inch diameter, but the even sizes are here given for convenience. The shafts are provided with roller bearings, and all pulleys with the exception of the large main driving pulleys are of the pressed sheet steel form, as being the lightest pulley made for strength, convenience, and transmission of power.

From the end of the main shaft toward the front of the building, power is taken for the machines in the tool room. From near the center, power is carried by a vertical belt to the gallery floor above. This shaft is 34 inches in diameter for the central 20-foot length and the remainder is 3 inches in diameter. Upon the central length, as well as on the main line below, are pulleys 48 inches in diameter and 14 inches face. The central length is supported by four hangers one at each end, and one on each side of the main pulley.

In all cases the couplings are to be placed on the side of the hanger away from the source of power, so as to be secure in case of the failure of a coupling. The dynamos for lighting as well as those for driving the motors may

be located in the engine room and driven by belts from the main line by friction pulleys, or they may be located under the main line shafting.

It should be remembered that for a belt of high velocity it will be much better to run it horizontally than vertically, and that it will transmit much more power under the former condition. If it is desired to locate the dynamos in the engine room and run them by horizontal belts, a countershaft may be located near the floor, just inside the engine room and driven by a belt from the main line.

An independent engine may be used to drive the motors. In this case the power of the main engine would be considerably reduced. The main line shaft furnishes power for all machines on that side of the main floor.

The machines on the opposite side of the main floor may be those which it is desired to drive by individual motors, while in the gallery above, the line shaft, in say three or four sections, may be driven by suitable motors.

The same method may be desirable in the pattern shop and also in the tool room, if preferred, although it is more adaptable in the pattern shop where power is not used continuously.

The power for driving the machines in the carpenter shop may be transmitted by belt from the main line through a belt box occupying the space between the machine shop and the carpenter shop to the line shaft in the latter. Or, a motor may be located in the carpenter shop.

If a steam hammer is used in the forge shop the steam supply should be carried in a pipe passing through an underground brick conduit, as carrying it around through the machine shop and carpenter shop would necessitate a long line of piping

A motor will be most convenient for operating the blast fan, drop hammers, cutting-off machines, power hack saws, etc.

For the foundry, steam may be carried under ground, across the yard in a brick conduit, as the most direct way, to the engine running the heating apparatus, and another for the cupola blower and the tumbling barrels. Here again motors will be very convenient, as one may be directly connected to the heating apparatus fan and another used for the cupola blower and the tumbling barrels, as well as to run the elevator which supplies the cupola platform with its fuel and stock.

The boilers, and at least all pipes over 14 inches in diameter, conveying live steam, should be protected with a good non-conducting covering. Probably the best preparation for this purpose is a mixture of carbonate of magnesia and asbestos, only a sufficient quantity of the latter being used as a bond, to hold the mixture together. The proportions may be, eight parts of magnesia and two parts of asbestos, with a sufficient quantity of water to form a plastic

mass.

The thickness of this covering will depend on the amount of exposure to cold air to which the boilers or steam pipes are subjected. From one to two inches is ordinarily used, according to circumstances.

CHAPTER XV

SOME CONCLUDING REMARKS

The choice of ground for manufacturing plants. Important requisites. High fixed expenses

of city locations. The quality of ground. Hard gravel the best. Drainage. Sewerage system. Grading the yards. Catch basins. Conductor piper and sewer connections. Makeshift devices. Cobblestone pavements. Foundation protection. Yard areas. Water-ways. Covering catch basins. Capacity of catch basins. General observations.

BEFORE concluding this subject there are some remarks of a more or less general nature which seem proper to make here rather than in any of the preceding chapters, as they have each been assigned to a specific division of the subject, and the effort has been made to confine them to that portion of the question as nearly as may be, without restricting their scope within too narrow boundaries for practical use, and the consideration of practical men.

The choice of the ground upon which to erect manufacturing buildings is one which should receive mature consideration for a number of important reasons, and in this respect the following are some of the more obvious ones which should claim earnest attention. The ground chosen for the proposed plant should be situated near enough to a railroad so that a spur track may be laid to the works, for convenience of bringing in coal, iron, lumber, and similar stock, as well as for shipping the product of the shops. This is a matter of all the more importance if heavy machinery is to be built, as the unnecessary handling of such products entails an ever present expense, which, in the case of having the convenience of a branch track to the works is practically met by the first cost of laying the track.

The ground selected should not be in the populous section of a town or city for several reasons, among which are: the high rate of taxation, the continual expense of obtaining a proper water supply, and the largely increased cost of the real estate necessary for the purpose. One manufacturing plant in a city of moderate size is now paying annually the exorbitant sum of fortyfive dollars per employee for taxes, and three dollars per employee for a water supply. In the outskirts of a city of the same size and advantages, the rate of taxation would be reduced to less than five dollars, and the water supply, if the plant is near a natural water-way, would be practically nominal. And

if not near a natural supply of water, it may be obtained in abundance by boring, or by driving wells, the first cost of which will practically end the expense.

Obviously, the buildings should not be erected on low ground, where the health of the employees may be endangered by inefficient drainage. Such land is not only unfit for the erection of manufacturing buildings, for the reasons given above, but low ground is liable to be of such a soft and yielding nature as to render foundations expensive and uncertain, particularly if the building is to be a heavy one, or if much heavy machinery requiring masonry foundations is to be used.

Buildings should not be erected on alluvial soil if it is possible to locate on land of a more substantial nature, for the above reason, and in consideration of the health of the employees.

The land should be of hard gravel, as being the best quality for the purpose, as strong foundations may be economically built, and the surface water is readily absorbed in places where it is inexpedient to drain it away. Rocky and clay land will, of course, offer a good bed for foundations, as the solid rocks may be built around and upon and the clay is very apt to be underlaid by a good “hard pan” of compact gravel which is an excellent bed for the same purpose. In building upon rocks, care must be taken to have all resting places for the foundation level, and if the original surface is not so, it must be chipped out, or cut to a level surface, or to several step-like horizontal surfaces, before any stone or brickwork is laid upon it.

As a matter of convenient drainage the ground should be high enough from some proper point where sewerage waste may be discharged to admit of a proper incline to the sewer and its connecting pipes. This is assuming, of course, that the plant is provided with its own sewerage system, as will necessarily be the case if it is outside of city limits, or in a country town where it is not within reach of the public sewers.

In planning a sewerage system the surface water of the yards must be properly taken care of. In grading the yards they should incline slightly toward some convenient point, as much out of the way of the passage of teams as possible, where a catch basin with a water seal trap may receive all of the surface water and still cut off sewer gas, and where convenient connection may be made with the sewer system.

Preferably, such catch basins and the connections from the roof water flow, or a good portion of it, should be furthest from the sewer outlet, and the connections from the wash rooms and water-closets enter the sewer at intermediate points, as this will provide for automatically flushing these connections at every rain storm. Conductor pipes from the roofs should lead directly to the sewers, rather than to pour the water out upon the ground, as

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