Chapter 4

By this means the thread which is passing from one pulley to the other is stretched by an amount equal to the difference of the winding speed of the two pulleys. In the diagram (Fig. 2) the thread passes, as shown by the arrows, over the pulley, P, and then over the pulley, P¹, the latter having a slightly greater winding speed. Between these pulleys it passes over the guide pulley, G. This latter is supported by a lever hinged at S, and movable between the stops, TT¹. W is an adjustable counterweight. When the thread is passed over the pulleys and guided in this manner, the stretch to which it is subjected tends to raise the guide and lever, so that the latter will be drawn up against the stop, T¹, when the thread is so coarse that the effort required to stretch it is sufficient to overcome the weight of the guide pulley and the adjustable counterweight. But as the thread becomes finer, which, in the case of reeling silk, happens either from the tapering of the filaments or the dropping off of a cocoon, a moment arrives when it is no longer strong enough to keep up the lever and counterweight. These then descend, and the lever touches the lower stop, T. It will be readily seen that the up and down movements of the lever can be made to take place when the thread has reached any desired maximum or minimum of size, the limits being fixed by suitably adjusting the counterweight.

In the automatic reeling machine this is the method employed for regulating the supply of cocoons. The counterweight being suitably adjusted, the lever falls when the thread has become fine enough to need another cocoon. The stop, T, and the lever serve as two parts of an electric contact, so that when they touch each other a circuit is completed, which trips a trigger and sets in motion the feed apparatus by which a new cocoon is added. In practice the two drums or pulleys are mounted on the same shaft, D (Fig. 1), difference of winding speed being obtained by making them of slightly different diameters.

The lever is mounted as a horizontal pendulum, and the less or greater stress required according to the size to be reeled is obtained by inclining its axis to a less or greater degree from the vertical. An arrangement is also adopted by which the strains existing in the thread when it arrives at the first drum are neutralized, so far as their effect upon the lever is concerned. This is accomplished by simply placing upon the lever an extra guide pulley, L¹, upon the side opposite to that which corresponds to the guide shown in the diagram, Fig. 2.

An electric contact is closed by a slight movement of the lever whenever the thread requires a new filament of cocoon, and broken again when the thread has been properly strengthened. It is evident that a delicate faller movement might be employed to set the feed mechanism in motion instead of the electric circuit, but, under the circumstances, as the motion is very slight and without force, being, in fact, comparable to the swinging of the beam of a balance through the space of about the sixteenth of an inch, it is simpler to use a contact.

The actual work of supplying the cocoons to the running thread is performed as follows: The cleaned cocoons are put into what is called the feeding basin, B1 (Fig. 1), a receptacle placed alongside of the ordinary reeling basin, B, of a filature. A circular elevator, E, into which the cocoons are charged by a slight current of water, lifts them over one corner of the reeling basin and drops them one by one through an aperture in a plate about six inches above the water of the reeling basin.

The end of the filament having been attached to a peg above the elevator, it happens that when a cocoon has been brought into the corner of the reeling basin, the filament is strung from it to the edge of the hole in the plate in such a position as to be readily seized by a mechanical finger, K (Fig. 3), attached to a truck arranged to run backward and forward along one side of the basin. This finger is mounted on an axis, and has a tang projecting at right angles to the side of the basin, so that the whole is in the form of a bell crank mounted on the truck.

There are usually four threads to each basin. When neither one of them needs an additional cocoon, the finger of the distributing apparatus remains, holding the filament of the cocoon at the corner of the basin where it has been dropped. When a circuit is closed by the weakening of any one of the threads, an electromagnetic catch is released, and the truck with its finger is drawn across the basin by a weight. At the same time the stop shown dotted in Fig. 3 is thrown out opposite to the thread that needs strengthening. This stop strikes the tang of the finger, and causes the latter to be thrown out near to the point at which the filaments going to make up the weakened thread are being drawn from the cocoons. Here the new filament is attached to the new running thread by a kind of revolving finger, J, called in France a "lance-bout." This contrivance takes the place of the agate of the ordinary filature, and is made up, essentially, of the following parts:

(1) A hollow axis, through the inside of which the thread passes instead of going through the hole of an agate. This hollow axis is furnished, near its lower end, with a ridge which serves to support a movable portion turning constantly round the axis. (2) A movable portion turning constantly round the axis. (3) A finger or hook fastened on the side of the movable portion and revolving with it. This hook, in revolving, catches the filament brought up by the finger and serves it on to the thread.

Such are the principal parts of the automatic reeling machine. Although the fact that this machine is entirely a new invention has necessitated a somewhat long explanation, its principal organs can nevertheless be summed up in a few words: (1) A controlling drum which serves to give the thread a constant elongation; (2) a pulley mounted on a pivot which closes an electric current every time that the thread becomes too fine, and attains, in consequence, its minimum strength, in other words, every time that a fresh cocoon is needed; (3) electromagnets with the necessary conducting wires; (4) the feeding basin; (5) distributing finger and stops; and (6) the lance-bout.

Our illustration, Fig. 1, shows diagrammatically a section through the cocoon frame and reel. The thread is composed of three, four, or more filaments, and after passing through the lance-bout, it travels as shown by the arrows. At first it is wound round itself about two hundred times, then passed over a fixed guide pulley, and over a second guide pulley lower down fixed to the frames which carry the lance-bouts, then up through the twist and over the smaller of the pulleys, D. Taking one complete turn, it is led round the guide pulley, L, from there round the larger of the pulleys, D, round the second guide pulley, L¹, then back to the large wheel, and over a fixed guide pulley across to the reeling frame. Power is supplied to the latter by means of a friction clutch, and to insure even winding the usual reciprocating motion of a guide is employed. The measuring apparatus is pivoted at F, and by raising or lowering the nuts at the end of the bar the required inclination is given.

We had recently an opportunity of examining the whole of this machinery in detail, and seeing the process of silk reeling in actual operation, Mr. Serrell having put up a complete set of his machines in Queen Victoria Street, London. Regarded simply as a piece of ingenious mechanism, the performance of these machines cannot fail to be of the highest interest to engineers, the reeling machine proper seeming almost endowed with human intelligence, so perfectly does it work. But, apart from the technical perfection, Mr. Serrell's improvements are of great importance as calculated to introduce the silk-reeling industry in this country on a large scale, while at the same time its effect upon India as a silk-growing country will be of equal importance.--_Industries._

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APPARATUS USED FOR MAKING ALCOHOL FOR HOSPITAL USE DURING THE CIVIL WAR BETWEEN THE STATES.[1]

[Footnote 1: Read at the Cincinnati meeting of the American Pharmaceutical Association.]

By CHARLES K. GALLAGHER, Washington, N.C.

A is an ordinary farm boiler or kettle, with an iron lid securely bolted on; B, a steam pipe ending in a coil within a trough, D. C, D, two troughs made of gum logs, one inverted over the other, securely luted and fastened together by clamps and wedges. The "beer" to be distilled was introduced at E and the opening closed with a plug. The distillate--"low wine"--was collected at F, and redistilled from a set of similar troughs not shown in above figure, and heated by a continuation of the steam coil from D.

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CONFEDERATE APPARATUS FOR MANUFACTURING SALTPETER FOR AMMUNITION.

By CHARLES K. GALLAGHER, Washington, N.C.

Any convenient number of percolators, made of rough boards, arranged over a trough after the style of the old fashioned "lye stand," similar to the figure. Into these was placed the earth scraped from around old tobacco barns, from under kitchens and smokehouses. Then water or water and urine was poured upon it until the mass was thoroughly leached or exhausted. The percolate was collected in a receptacle and evaporated, the salt redissolved, filtered, again evaporated, and crystallized from the mother water.

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THE TELEMETER SYSTEM.

By F.R. UPTON.

In this paper, read before the British Association, the author explained that the "Telemeter System," invented by C.L. Clarke, of New York, is a method by which the slow movement of a revolving hand of any indicating instrument may be reproduced by the movement of a similar hand at a distant place, using electricity to convey the impulse. The primary hand moves until it makes electrical contact, thus sending an impulse. It is here that all previous methods have failed. This contact should be absolute and positive, for if it is not, the receiver will not work in unison. The contact could often be doubled by the jarring of the instrument, thus making the receiver jump twice. Clarke has overcome this defect by so arranging his mechanism that the faintest contact in the primary instrument closes two platinum points in multiple arc with it, thus making a firm and positive contact, which is not disturbed by any jar on the primary contact. This gives the instruments a positive start for the series of operations, instead of the faint contact which would be given, for example, by the light and slowly moving hand of a metallic thermometer. The other trouble with previous methods was that the contact points would corrode, and, in consequence of such corrosion, the instrument would fail to send impulses. Corrosion of the contacts is due to breaking the circuit slowly on a small surface. This is entirely remedied by breaking the circuit elsewhere than at the primary contact, using a quick motion, and also by giving this breaking contact large surface and making it firm. The instrument, as applied to a thermometer, is made as follows: From the free end of the light spiral of a metallic thermometer fixed at the other end, an arm, C, is attached, the end of which moves over an arc of a circle when the temperature varies. This end carries on either side of its extremity platinum contacts which, when the thermometer is at rest, lie between two other platinum points, A B, carried on radial arms. Any variation in temperature brings a point on the thermometer arm in contact with one of these points, and thus gives the initial start to the series of operations without opposing any friction to the free motion of the instrument. The first result is the closing of a short circuit round the initial point of contact, so that no current flows through it. Then the magnets which operate one set of pawls come into play. The two contact points are attached to a toothed wheel in which the pawls play, and these pawls are so arranged that they drive the wheel whenever moved by their magnets; thus the primary contact is broken.

In the receiver there is a similar toothed wheel carrying the hand of the indicating instrument, and actuated at the same moment as the transmitter. The primary contacts are so arranged that the contact is made for each degree of temperature to be indicated. This series of operations leaves the instruments closed and the pawls home in the toothed wheel. To break the circuit another wire and separate set of contacts are employed.

These are arranged on the arms carrying the pawls, and so adjusted that no contact is made until after the toothed wheel has moved a degree, when a circuit is closed and a magnet attracts an armature attached to a pendulum. This pendulum, after starting, breaks the circuit of the magnets which hold the pawls down, as well as of the short-circuiting device. As the pendulum takes an appreciable time to vibrate, this allows all the magnets to drop back, and breaks all circuits, leaving the primary contacts in the same relation as at first. The many details of the instruments are carefully worked out. All the contacts are of a rubbing nature, thus avoiding danger from dirt, and they are made with springs, so as not to be affected by jar.

The receiving instruments can be made recorders also by simple devices. Thus, having only a most delicate pressure in the primary instrument, a distinct ink record may be made in the receiver, even though the paper be rough and soft. The method is applicable to steam gauges, water indicators, clocks, barometers, etc., in fact, to any measuring instrument where a moving hand can be employed.

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A NEW MONSTER REVOLVING BLACK ASH FURNACE AND THE WORK DONE WITH IT.

By WATSON SMITH, Lecturer in Chemical Technology in the Victoria University, etc.

The Widnes Alkali Company, limited, to which I am indebted for permission to describe this latest addition to a family of revolving black ash furnaces, of late not only increasing in number, but also individual size, has kindly allowed my friend, Mr. H. Baker, to photograph the great revolver in question, and I have pleasure now in throwing on the screen a picture of it, and also one of a revolver of ordinary size, so as to render a comparison possible. The revolver of ordinary size measures at most 18½ ft. long, with a diameter of 12½ ft. The boiling down pans connected with such a furnace measure 60 ft. in length. Each charge contains four tons of salt cake, and some of these revolvers get through 18 tons of salt cake per day and consume 13 cwt. of coal per ton of cake decomposed.

With regard to the larger revolver, it may be just said that the Widnes Alkali Company has not at once sprung to the adoption of a furnace of the immense size to be presently given, but in 1884 it erected a revolver only about 3 ft. to 4 ft. short of the length of that one, and having two discharging holes. The giant revolving furnace to be described measures in length 30 ft. and has a diameter of 12 ft. 6 in. Inside length is 28 ft. 6 in., with a diameter of 11 ft. 4 in. It is lined with 16,000 fire bricks and 120 fire-clay blocks or breakers, weighing each 1¼ cwt. The bricks weigh per 1,000 about four tons. The weight of salt cake per charge (i.e., contained in each charge of salt cake, limestone, mud, and slack) is 8 tons 12 cwt. For 100 tons of salt cake charged, there are also charged about 110 tons of lime mud and limestone and 55 tons of mixing slack. In a week of seven days about 48 charges are worked through, weighing of raw materials about 25 _tons per charge_. The total amount of salt cake decomposed weekly is about 400 tons, and may be reckoned as yielding 240 tons of 60 per cent. caustic soda. As regards fuel used for firing, this may be put down as 200 tons per week, or about 10 cwt. per ton of salt cake decomposed. Also with regard to the concentration of liquor from 20° Tw. to 50° Tw., there is sufficient of such concentrated liquor evaporated down to keep three self-fired caustic pots working, which are boiled at a strength of 80° Tw. Were it not for this liquor, no less than seven self-fired pots would be required to do this work, showing a difference of 80 tons of fuel.

The question may be asked, "Why increase the size of these huge pieces of apparatus?" The answer, I apprehend, is that owing to competition and reduction of prices, greater efforts are necessary to reduce costs. With automatic apparatus like the black ash revolver, we may consider no very sensible addition of man power would be needed, in passing from the smallest sized to the largest sized revolver. Then, again, we may, reckoning a certain constant amount of heat lost per each revolver furnace of the small size, consider that if we doubled the size of such revolver, we should lose by no means double the amount of heat lost with the small apparatus; but only the same as that lost in the small furnace _plus_ a certain fraction of that quantity, which will be smaller the better and more efficient the arrangements are. Then, again, there is an economy in iron plate for such a large revolver; there is economy in expense on the engine power and on fuel consumed, as well as in wear and tear.

Just to mention fuel alone, we saw that with an ordinary large sized revolver, the coal consumption was 13 cwt. per ton of salt cake decomposed in the black ash process; but with the giant revolver we have been describing, that consumption is reduced to 10 cwt. per ton of cake decomposed.

The question will be probably asked, How is it possible to get a flame from one furnace to carry through such a long revolver and do its work in fusing the black ash mixture effectively from one end to the other? The furnace employed viewed in front looks very like an ordinary revolver fireplace, but at the side thereof, in line with the front of the revolver, at which the discharge of the "crude soda" takes place, there are observed to be three "charging holes," rather than doors, through which fuel is charged from a platform directly into the furnace through those holes.

The furnace is of course a larger one than furnaces adjusted to revolvers of the usual size. But the effect of one charging door in front and three at the side, which after charging are "banked" up with coal, with the exception of a small aperture above for admission of air, is very similar to that sometimes adopted in the laboratory for increasing heating effect by joining several Bunsen lamps together to produce one large, powerful flame. In this case, the four charging holes represent, as it were, the air apertures of the several Bunsen lamps. Of course the one firing door at front would be totally inadequate to supply and feed a fire capable of yielding a flame that would be adequate for the working of so huge a revolver. As an effort of chemical engineering, it is a very interesting example of what skill and enterprise in that direction alone will do in reducing costs, without in the least modifying the chemical reactions taking place.--_Journal Soc. Chem. Industry._

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IMPROVEMENTS IN THE MANUFACTURE OF PORTLAND CEMENT.[1]

[Footnote 1: A paper recently read before the British Association.]

By FREDERICK RANSOMS, A.I.C.E.

So much has been said and written on and in relation to Portland cement that further communications upon the subject may appear to many of the present company to be superfluous. But is this really so? The author thinks not, and he hopes by the following communication, to place before this meeting and the community at large some facts which have up to the present time, or until within a very recent date, been practically disregarded or overlooked in the production of this very important and valuable material, so essential in carrying out the great and important works of the present day, whether of docks and harbors, our coast defenses, or our more numerous operations on land, including the construction of our railways, tunnels, and bridges, aqueducts, viaducts, foundations, etc. The author does not propose to occupy the time of this meeting by referring to the origin or the circumstances attendant upon the early history of this material, the manufacture of which has now assumed such gigantic proportions--these matters have already been fully dealt with by other more competent authorities; but rather to direct the attention of those interested therein to certain modifications, which he considers improvements, by means of which a large proportion of capital unnecessarily involved in its manufacture may be set free in the future, the method of manufacture simplified, the cost of manipulation reduced, and stronger and more uniformly reliable cement be placed within the reach of those upon whom devolves the duty and responsibility of constructing works of a substantial and permanent character; but in order to do this it will be necessary to allude to certain palpable errors and defects which, in the author's opinion, are perpetuated, and are in general practice at the present day.

Portland cement is, as is well known, composed of a mixture of chalk, or other carbonate of lime, and clay--such as is obtained on the banks of the Thames or the Medway--intimately mixed and then subjected to heat in a kiln, producing incipient fusion, and thereby forming a chemical combination of lime with silica and alumina, or practically of lime with dehydrated clay. In order to effect this, the usual method is to place the mechanically mixed chalk and clay (technically called slurry), in lumps varying in size, say, from 4 to 10 lb., in kilns with alternate layers of coke, and raise the mass to a glowing heat sufficient to effect the required combination, in the form of very hard clinker. These kilns differ in capacity, but perhaps a fair average size would be capable of producing about 30 tons of clinker, requiring for the operation, say, from 60 to 70 tons of dried slurry, with from 12 to 15 tons of coke or other fuel. The kiln, after being thus loaded, is lighted by means of wood and shavings at the base, and, as a matter of course, the lumps of slurry at the lower part of the kiln are burned first, but the moisture and sulphurous gases liberated by the heat are condensed by the cooler layers above, and remain until the heat from combustion, gradually ascending, raises the temperature to a sufficient degree to drive them further upward, until at length they escape at the top of the kiln. The time occupied in loading, burning, and drawing a kiln of 30 tons of clinker averages about seven days. It will be readily understood that the outside of the clinker so produced must have been subjected to a much greater amount of heat then was necessary, before the center of such clinker could have received sufficient to have produced the incipient fusion necessary to effect the chemical combination of its ingredients; and the result is not only a considerable waste of heat, but, as always occurs, the clinker is not uniformly burnt, a portion of the outer part has to be discarded as overburnt and useless, while the inner part is not sufficiently burnt, and has to be reburned afterward. Moreover, the clinker, which is of excessively hard character, has to be reduced by means of a crusher to particles sufficiently small to be admitted by the millstones, where it is ground into a fine powder, and becomes the Portland cement of commerce.