Chapter 3

I will now show you by a practical utilization of the well known flameless combustion, how to light a coke furnace without either paper or wood, and without disturbing the fuel, by the use of a blowpipe which for the first minute is allowed to work in the ordinary way with a flame to ignite the coke. I then pinch the gas tube to extinguish the flame, allow the gas to pass as before, and so blow a mixture of unburnt air and gas into the fuel. The enormous heat generated by the combustion of the mixture in contact with the solid fuel will be appreciable to you all, and if this blast of mixed air and gas is continued, there is hardly any limit to the temperatures which can be obtained in a furnace. I shall be able to show you the difference in temperature obtained in a furnace by an ordinary air blast, by a blowpipe flame directed into the furnace, and by the same mixture of gas and air which I use in the blowpipe being blown in and burnt in contact with the ignited coke. In each case the air blast, both in quantity and pressure, is absolutely the same; but the roar and the intense, blinding glare produced by blowing the unburnt mixture into the furnace is unmistakable. The heat obtained in the coke furnace I am using, in less than ten minutes, is greater than any known crucible would stand. I am informed that this system of air and gas or air and petroleum vapor blast, first discovered and published by myself in a work on metallurgy issued in 1881, is now becoming largely used for commercial purposes on the Continent, not only on account of the enormous increase in the heat, and the consequent work got out of any specified furnace, but also because the coke or solid fuel used stands much longer, and the dropping, which is so great a nuisance in crucible furnaces, is almost entirely prevented; in fact, once the furnace is started, no solid fuel is necessary, and the coke as it burns away can be replaced with lumps of broken ganister or any infusible material. Few, if any, samples of firebrick will stand the heat of this blast, if the system is fully utilized. You will find it a matter of little difficulty, with this system of using gas, to melt a crucible of cast iron in an ordinary bed-room fire grate if the front bars are covered with sheet iron, with a hole (say) three inches in diameter, to admit the combined gas and air blast. The only care needed is to see that you do not melt down the firebars during the process. I will also show you how, on an ordinary table, with a small pan of broken coke and the same blowpipe, used in the way already described, you can get a good welding heat in a few minutes, starting all cold. In this case the blowpipe is simply fixed with the nozzle six inches above the coke, and the flame directed downward. As soon as the coke shows red, the gas pipe is pinched so as to blow the flame out, and the mixture of gas and air is blown from above into the coke as before. With this and a little practice, you can get a weld on a 7/8 inch round bar in 10 minutes.

There is one use of gas which has already proved an immense service to those who, in the strictest sense, live by their wits. In a small private workshop, with the assistance of gas furnaces, blowpipes, and other gas heating appliances, it is a very easy matter to carry out important experiments privately on a practical scale. A man with an idea can readily carry out his idea without skilled assistance, and without it ever making its appearance in the works until it is an accomplished fact. How many of you have been blocked in important experiments by the tacit resistance of an old fashioned good workman, who cannot or will not see what you are driving at, and who persists in saying that what you want is not possible? The application of gas will often enable you to go over his head, and do what, if the workman had his own way, would be an impossibility. When a man is unable or unwilling to see a way out of a difficulty, a master or foreman has the power to take the law in his own hands; and when a workman has been met with this kind of a reply once or twice, he usually gives way, and does not in future attempt to dictate and teach his master his own business. In carrying out this matter, it is not necessary that a specimen of fine workmanship shall be produced. A man usually appreciates the wits which have produced what he has considered impossible. In purely experimental work I think I may fairly state that the use of gas as a fuel in the private workshop and laboratory has done incalculable service in the improvement of processes and trades, and has played an important part in insuring the success and fortunes of many hundreds of experimenters, who have brought their labors to a successful issue in cases where, in its absence, neither time nor patience would have been available. I need only to call to your mind the number of new alloys which, for almost endless different purposes, have come into use during the last eight or ten years. I think the use of small gas furnaces in private workshops and laboratories may fairly be said to have enabled the experiments on most, if not all, of these alloys to be carried out to a successful issue.

I have been asked to say something regarding gas engines. The only thing I can say is that I know very little about them. In my own works we have about 300,000 cubic feet of space, all of which requires to be heated, more or less, during the greater part of the year. For this purpose we must have a steam boiler, and having this steam, it costs little to run it first through the engine, and so obtain our power for a good part of the year practically without any cost. It would not pay, under any circumstances, to have two separate sources of power for summer and winter; and therefore the use of gas for power has never been considered.

For irregular work and comparatively small powers, gas-engines have special and great advantages; and in this respect they may, perhaps, class with gas melting furnaces. If I wanted 1, or 10, or 20 lb. of melted metal, I could melt and make the casting in less time and with less cost than would be required to light a coke fire. There is no possible comparison in the two, as to convenience and economy; but if I wanted to melt 3 or 4 cwt. or 3 or 4 tons every day, I should not dream of using gas for the purpose, as the extra cost of gas in such a case would not be compensated by the saving in time. In commercial matters we must always consider first what is the most profitable way of going about our work; and, so far as I myself am concerned, I have always found it advantageous to expend some money annually on proving this by direct experiment. It is almost always possible to learn something, even from a failure.

I will now, with a blowpipe and small foot blower, heat a short length of locomotive boiler tube to a brazing heat on the table; and, in conclusion, will convert the table into a small foundry. I cannot cast you a flywheel for a factory engine; so will try at something smaller, and will reproduce a medallion portrait of Her Majesty, in cast iron, the original of which is silver, commonly valued at half a crown. From the time I light the furnace until I turn you out the finished casting I shall perhaps keep you eight or nine minutes. I can remember in the good old times 25 years ago, before I used gas furnaces, that it sometimes took about two hours to get a good wind furnace into condition to put the crucible in. My time in those days was not worth much; but if I valued it at 2s. 6d. per week, it would even then have been cheaper to use gas to do the same thing, irrespective of the cost of coke.

The age of gaseous fuel is commencing; and I feel daily, from the correspondence I receive, that there is a growing impression that gas is going to perform miracles. We do not need to go mad about it; and my own precept and practice is to employ gas only where its use shows a profit, either in time or money. Many of those present know that I am as ready to totally condemn gaseous fuel where it does not pay as to advise its use where some advantage is to be gained. You will understand that my remarks apply to coal gas only. As to producer or furnace gases, I know practically nothing, except that sometimes it pays better to burn your candle as a candle than make it into gas, and burn it as a gas afterward. The use of producer gas no doubt pays on a large scale; and things on a large scale, so far as gas is concerned, are not matters with which I have time to concern myself. The commercial use of coal gas has yet to be developed. It is in its infancy; and there are very few, if any, who have any conception of its endless uses, both for domestic and manufacturing purposes. The more general the information which can be given about its uses, the sooner it will find its own level, and the sooner the gas companies will appreciate the fact that their best customers are to be found among those who can use coal gas as a fuel for special work in manufacturing industries because it is profitable to use, and saves expensive labor. My own experiments with alloys of the rarer metals, which have not been concluded without profit to myself, would certainly never have been undertaken except with the use of gas furnaces, which were both practically unlimited in power and admitted of the most absolute precision in use; and I may safely say, without violating any confidence, that many of the precious stories and so-called "natural" products make their appearance in the world first in a crucible in a gas furnace.

At the conclusion of my lecture before the Institute at Leeds, on "Combustion and the Utilization of Waste Heat," Mr. Kitson, the Chairman, remarked that if he were a dreamer of dreams, he might look forward to the time when he would be growing cucumbers with the waste heat of his iron furnaces. Many wilder dreams than this have come true in the science of engineering; and the realization has brought honor and fortune to the dreamers, as you must all know. The history of engineering is full of the realization of "dreams," which have been denounced as absurdities by some of the best living authorities.

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THE GAS METER

The gas meter was invented by Clegg in 1816. Since that epoch no essential modification has been made of its structure. Fig. 1 shows the principle of the apparatus, _mnpq_ is a drum movable around a horizontal axis. This is divided by partitions of peculiar form into four vessels of equal capacity, and dips into a closed water reservoir, RR'. A tube, _t_, near the axis, and the orifice of which is above the level of the water, leads the gas to be measured. This latter enters under the partition, _l'm_, of one of the buckets, and exerts an upward thrust upon it that communicates a rotary motion to the drum. The bucket, _l'mi_, closed hydraulically, rises and fills with gas until the following one comes to occupy its place above the entrance tube and fills with gas in turn. Simultaneously, as soon as the edge of each bucket emerges at _e_, the gas flows out through the opening that the water ceases to close, and escapes from the reservoir through the exit aperture, S. The gas, in continuing to traverse the system, is thus filling one bucket while the preceding one is losing its contents; so that, if the capacity of each bucket is known, the volumes of the gas discharged will likewise be known when the number of revolutions made by the drum shall have been counted. The addition of a revolution counter to the drum, then, will solve the problem.

The instrument, as usually constructed, is shown in Figs. 2 and 3.

The reservoir, RR' contains the measuring drum, _mmmm_, movable around the horizontal axis, _aa'_. The gas enters at E, passes at S into an opening that may be closed by a valve, and is distributed through the box, BB', which communicates with the reservoir through an orifice in the partition, _hh'_. This orifice is traversed by the axle, _aa'_. The box, like the reservoir, contains water up to a certain level, _r_. Through a U-shaped tube, _lnl'_, the gas passes from the box, BB', into the movable drum, sets the latter in motion, and makes its exit at S. In order to count the volume discharged, that is to say, the number of revolutions of the drum, the axle terminates at a in an endless screw which, by means of a cog wheel, moves a vertical rod that traverses the tube, _gg_, and projects from the box. As the tube, _gg_, dips into the water, it does not allow the gas to escape, and this permits of the revolution counter that the rod actuates being placed in an external case, CC'.

The counter consists of toothed wheels and pinions so arranged that if the first wheel makes one complete revolution corresponding to a discharge of 1,000 liters, the following wheel, which indicates cubic meters, shall advance one division, and that if this second wheel makes one complete revolution marked 10 cubic meters, the third, which indicates tenths, shall advance one division, and so on. Hands fixed to the axles of the wheels, and movable over dials, permit the volume of gas to be read that has traversed the counter.

The object of the other parts of the instrument are to secure regularity in its operation by keeping the level of the liquid constant. It is evident, in fact, that if the level of the water gets below _r_, the capacity of the buckets will be increased, and the counter will indicate a discharge less than is really the case, and _vice versa_. If the level descends as far as to the orifice in the partition, _hh'_, the gas will flow out without causing the apparatus to move. The water is introduced into the counter through _f_, which is closed with a screw cap, and passes through the opening shown by dotted lines into the reservoir, RR', whence it flows to the box, BB', When it has reached the desired level, it gains the orifice, _r_, of a waste pipe, escapes through the siphon, _ruv_, and makes its exit through the aperture, _b'_, when the screw cap of the latter is removed. If, by accident, the level of the water should fall below a certain limit, a float, _f_, which follows its every movement, would close the valve, _s_, and stop the flow of the gas. Finally a tube, _tt'_ soldered to the lower part of the tube, _lnl'_, and dipping into the water of a compartment, P, serves to allow the surplus water to flow out at _b'_. To prevent the apparatus from being disarranged upon the drum being revolved in the opposite direction, there is fixed to the axle, _aa'_, a cam which lifts a click, _z_, when the rotation is regular, but which is arrested by it when the contrary is the case.--_Science et Nature_.

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DOBSON AND BARLOW'S IMPROVEMENTS IN HEILMANN'S COMBERS.

Next to the mule, there is no doubt that the most beautiful machine used in the cotton trade is Heilmann's comber. Although the details of this machine are hard to master, when once its action is understood it will be found to be really simple. The object of combing is to remove the short staples and the dirt left in after the carding of the cotton, such as is used in the spinning of fine and even coarse numbers. The operation is an extremely delicate one, and its successful realization is a good illustration of what is possible with machinery. Combing machines are usually made with six heads, and sometimes with eight. As the working of each head is identical, we only speak of one of them. By means of a pair of fluted feeding rollers a narrow lap, about 7½ in. wide, is passed into the head, in which the following action takes place: Assuming that the stroke is finished, the lap is seized near its end by a pair of nippers, so as to leave about half the length of the staple projecting. These projecting fibers are combed by a revolving cylinder, partially covered with comb teeth. When the front or projecting ends of the fibers are thus combed, a straight comb in front of the nippers drops into them, the nippers open, and the fibers are drawn through the straight comb. This combs the tail ends, and at the same time the fibers, now completely combed, are placed on or pieced to the fibers that had been combed in the previous stroke, producing in this way a continuous fleece of combed cotton. In short, in this most striking operation, the fiber during the combing is completely detached from the ribbon lap, carried over, and pieced to the tail end of the combed fleece, for a moment having no connection with either. Since the expiry of the patent, Messrs. Bobson and Barlow, of Bolton, have constructed a great many of these machines, and have found that, as compared with the original make, it was possible to greatly increase their efficiency. They accordingly devoted much attention to this object, and have patents for several improvements. To describe these so as to be understood by everybody would be a most difficult task, and would take more space than we can afford. We simply wish to record what these improvements are, and will suppose we are writing for those who have a good acquaintance with Heilmann's comber.

We give herewith a perspective view of the improved machine. On examination it will be noticed that an alteration is made in the motion seen at the end of the machine for working the detached rollers. This alteration we believe to be a decided improvement over Heilmann's original arrangement. It dispenses with the large detaching cam, the cradle, the notch-wheel, the catch and its spring, the large spur wheel which drives the calender roller, and the internal wheels for the detaching roller-shaft, substituting in their stead a much simpler motion, consisting of a smaller cam, a quadrant, and a clutch. The arrangement, having fewer parts, is also much more compact than the old one, for with the driving pulleys in the best position it enables the machine outside the framing to be shortened 10 in., an important point in a room full of combers. The action of this detaching motion is positive, and enables the machine to be run at a high speed without danger of missing, as happens when the point of the catch for the old notch-wheel becomes broken or worn away. Another important feature of the new arrangement is that it allows the motion of the detaching-roller to be varied. By an adjustment, easily made in a few seconds, the delivery may be altered to suit different classes of cotton or kinds of work without the necessity of changing the cams or the notch-wheels.

An improvement has been made in the construction of the nippers. In the ordinary Heilmann's comber, the upper blade has a groove in its nipping edge, and the cushion plate is covered with cloth and leather, the fibers being held by the grip between the leather of the cushion plate and the edges of the groove in the upper blade, or knife, as it is called. The objections to this mode of construction were that the leather on the cushion plate required frequent renewing, and unless the adjustment was more accurate than could always be relied on, the grip of the nippers was not perfect, for while at one end the nipper might be closed, at the other end it might be open wide enough to allow the cotton to be pulled through by the combing cylinder, and made into waste. In Messrs. Dobson and Barlow's nipper there is neither cloth nor leather on the cushion plate. Its edge is made into a blunt ^, upon which the narrow flat surface of a strip of India rubber or leather fixed in the knife falls to give the nip. By this plan the cushion is applied to the knife instead of to the plate, which of course makes the cushion plate, after it has once been set, a fixture; it also dispenses with the accurate setting, as is now necessary in the old arrangement. It further does away with the frequent and expensive covering of the cushion-plate with roller leather and cloth, thus effecting a considerable saving, not only in cost of material, but also in labor, inasmuch as the nipper knives can be taken off, recovered, and replaced in one-sixth the time required to cover the cushion plates and replace them on the old system. American cotton of 7/8" staple to silk of 2½" staple can also be combed by this improved arrangement, an achievement which has been attempted by many, but hitherto without arriving at any success. Messrs. Dobson and Barlow have however overcome the difficulty by their improvements, which combine three important qualities, viz., simplicity, perfection, and cheapness. Many hundreds of other makers' machines have been altered to their new arrangements. The cam for working the nipper has also been altered to give a smoother motion than usual; one that moves the nipper quietly and without jerks when the machine runs from 80 to 95 strokes per minute. A very decided improvement has been made in the construction of the combing cylinder. The combs are always fixed on a piece called the "half-lap," which, in its turn, is secured to a barrel called the "comb-stock." Now it is very desirable and important that these half-laps should be perfectly true and exactly interchangeable. When one half-lap is taken off for repairs, another half-lap must be ready to take its place on the cylinder. The original mode in which the cylinders were made rendered it a matter of mechanical difficulty--almost an impossibility in the machine shop--to produce them exactly alike. To avoid this difficulty, Messrs. Dobson and Barlow have reconstructed the combing cylinder, and the parts being fitted together by simple turning or boring, accuracy and interchangeability can always be depended upon. The screws which fasten the cylinder to the shaft are also cased up with the cylinder tins, thus avoiding any accumulation of fly on the screw heads.

The motion for working the top detaching, the leather, or the piecing roller, as it is variously called, has also been improved. The ends of this roller are always carried on the top of two levers that are oscillated by a connecting rod attached to their bottom ends. In the new motion the connecting rod is dispensed with, and one joint saved. The joint that remains is at the foot of the levers that carry the leather roller. This joint is constructed so that it may be easily altered, and by its means one of the most delicate settings of the combing machine, viz., that of the leather roller, may be made with greater readiness than with the old system. Further, from the mode of mounting these rollers another advantage is gained in the facility of setting them. In setting with the old arrangement, only one end of the roller is adjusted at a time; in the new, the adjustment sets the ends of two rollers. With regard to the leather roller also, it was found that as the round brass tubes in which its ends revolved had very little wearing surface, they got worn into flats on the outside, and thus worked inaccurately. In the machine under notice this defect is remedied. The tubes are made square on the outside, and having ample bearing surface they keep their adjustment perfectly.