« ZurückWeiter »
ON THE CAUSES OF INJURY TO STEAM BOILERS.-BY C, W. WILLIAMS, ESQ.
Sir, -- In my last paper on this subject, containing boiling water from the fire, I explained some of the causes of those and placing it on the hand, for an instant, injuries to which steam-boilers are ex and without injury. I may here observe, posed, and dwelt on the circumstance, that I was not able to discover any difthat the sediment assumes two distinct ference between the temperature of the forms, namely, that of a solid crystallized two conductor pins. incrustation, and of a loose mud-like Now, since no heat was received by body, held merely in suspension. I the water, in either case, except what showed that the first could not be the passed longitudinally through the concause of injury to the “iron plates of ductor pins, it is manifest that the entire boilers, inasmuch as it was itself a good heat which raised the water to the boiling conductor of heat; whereas the second point, and maintained it in a state of the floating matter—would become a po active ebullition, must have passed sitive non-conductor, if allowed to sub- through a vertical section of the side of side, when the boiler had been at rest for the vessel, of but three-quarters of an some hours, and when it would assume inch square. This experiment therefore the dry hard consistence of plaster of proved, first, that this three-quarter-inch Paris.
surface of the boiler plate was sufficient I now propose to give further proofs for the transmission of a quantity of beat of the conductibility of this solid crystal out of all proportion greater than could lized incrustation, and draw some import have been transmitted by such area under ant inferences therefrom. I had two pins ordinary circumstances; second, that constructed, to act as conductors, each this incrustation, (which was crystallized three inches long and three-quarters of sulphate of lime,) possessed an admirable an inch square, one made of iron, and conducting property; and, third, that the other cut from a large slab of in no possible injury could be sustained by crustation taken from the interior of a the conductor itself, so long as its ternmarine boiler. These were inserted into perature remained so low. separate vessels, containing water, the The first of these facts shows how erone end projecting half an inch into the roneous have been our previous modes of water, through the side, and the remain estimating the evaporative power of any ing part projecting outwards, to receive kind of boiler, or fuel, by calculations the heat from a powerful gas-burner. drawn from the mere areas of the exThese vessels were so protected, that no posed plates; while it proves that much heat could reach them, except what passed may yet be done in this department of longitudinally, and exclusively through the boiler. The second shows that, in the conductor pins; consequently, the this crystallized state of the deposit, it water received no heat except what was cannot be the cause of injury to the conveyed, by conduction, through those plates, although the uncrystallized or pins.
loose matter, if allowed to settle and be. By means of the iron conductor pin, come hard, becomes a mischievous nonthe water was made to boil in 13 minutes, conductor, and the direct source of injury and by the incrustation conductor pin, in from overheating and bulging. The third 17} minutes. That the pins themselves proves, that if the recipient body to which were not raised to any inconveniently high the heat is conveyed be able to absorb temperature was proved by the fact, that the heat as fast as it is passed through when suddenly removed from the flame, the conducting body, no injury can be which was very intense, and while the sustained by the latter, seeing that this water was fiercely boiling, the pins them solid mass of incrustation, (hitherto supselves were at a temperature so low as to posed to be a bad conductor,) itself reallow the finger to be pressed against maining unaffected, was equal to the conthem without inconvenience; it cer veyance of a very powerful heat, through tainly did not appear to be above 500 or no less than three inches; while, in fact, 600 degrees-a temperature far too low it never reaches to above half an inch in to produce any injurious effect on their thickness on those parts of boiler plates structure. This experiment resembled which are exposed to the greatest heat. the well known one of taking a kettle Now, to apply these facts, and the in
ON THE CAUSES OF INJURY TO STEAM BOILERS.
119 ferences to which they lead, to practice. above 5 feet perpendicular, and but 5 We find that, so long as the water is
inches wide, thus leaving a space of but maintained in contact with the plates 24 inches for the water approaching the through which heat is conveyed by con side plates of each of the furnaces, and duction, no injury will be sustained. But the steam generated by the heat received the question arises—what is there to in- through such plates. This steam was terrupt this contact, and what other re necessarily so great in quantity, as to cipients than water, are to be met with
prevent the access of the water, and in in boilers? In land engine boilers, no fact became itself the recipient of the injury can arise to the plates from any
heat from the furnaces; the consequence circumstance connected with the furnace was, that the plates became overheated, or fuel, beyond the ordinary wear and bulged, and cracked, and extensive in. tear, (the sources of which will be here- jury was sustained by them during every after examined,) if due attention be paid voyage. Not unfrequently they required to cleanliness in the interior, and main to be wholly removed and replaced at à taining the water at its proper level. Ma considerable expense before a new voyage rine boilers, however, from their peculiar- could be commenced. ity of construction, are subject to another That steam, in fact, was the recipient source of injury, and which is too often of the heat in those narrow passages, destructive of the plates connected with where water should always predominate, their furnaces and the parts adjacent. was proved by a very simple and conThis peculiarity consists of numerous clusive experiment of the engineer, durvertical narrow passages. In these, the ing one of his voyages. He introduced a steam, as fast as it is generated, becomes, trial pipe in the space, (erroneously, in by reason of its ascending current, so this instance, called the water-space,) mixed with the water, as seriously to between two of the furnaces, and on a obstruct the free and continued access of level with the fuel- the inner end openthe latter to the plates. This also takes ing into such space, and the outer end place to the greatest extent in those parts projecting outside the boiler, and being which are exposed to the highest temper furnished with a stop-cock. The result ature, since such ascending current of proved his anticipation; for on trying steam is necessarily the greatest where this pipe, when the furnace was active, the heat is greatest, namely, in the side he could never draw off any thing but plates of the furnaces. The consequence steam. This circumstance was is, that these side plates, through which clusive, that although the water continued the heat is conveyed to the interior of at its proper level in the boiler, yet, by such narrow passages, are
more fre. reason of the confined nature of the quently overheated and bulged than passages, and the absence of a free circuother parts, though exposed to even a sation and access of the water, (at the still higher temperature from the direct very place, which of all others, required action of the flame.
its continual presence,) the steam, a bad The heating of the side plates of the recipient, had usurped its place. This furnaces of marine boilers, may therefore source of injury continuing, the furnace be said to arise solely from the circum side plates, as constantly, were deranged, stance, that by reason of the conflicting while the roofs and other parts remained currents of steam and water, in those sound to the last. narrow passages, or water-ways, the re From the instance here adduced, it cipient, being then a mixture of water does not follow that any given width of and steam, (too often of the latter alone,) water-space is necessary, or that narrow the heat cannot be taken up as rapidly as spaces must always be injurious. I have the metal conveys it, and the usual con frequently observed that spaces of but sequences of over heating necessarily fol 3 inches wide between the furnaces have low.
been unattended with injury to the plates. This interposition of steam, where The cause of injury then, arising from water alone should be found, and its ine the predominance of steam instead of vitably injurious consequences, were strik water, is rather to be traced to other ingly illustrated in the first boilers of the circumstances connected with the circutransatlantic steam ship, the Liverpool. lation of the water in the boiler, and the In these boilers, the water spaces were aids or impediments it receives from the
peculiar construction or arrangement of ceived by the plane outer side of such the flues.
plate. « Ribbed plates," as suggested The main practical consideration, then, by your correspondent, certainly have in seeking to protect the plates of boilers their value in many respects; as where from overheating, is, that it is not to the a slower and more uniform absorption of fire, or furnace, that attention should be heat by the liquid is advisable, as in some directed, but simply and solely to the saline, gelatinous, or other bodies; but, pature of the recipient to which the heat with reference to my object, the mere is conveyed, for in this will be found to evaporation of water, such I have found rest the whole question of injury. This in a great degree to be injurious. will be objected to by those who have There are in boilers the two surfaces hitherto anticipated danger from hard or sides of a plate to be attended to, firing and incrustation, and the want of namely, the inner, or heat-distributing due proportions between the fire and flue surface in contact with the liquid; and surface. Yet I state the position broadly, the outer, or heat-absorbing surface ex. after the fullest investigation and the posed to the fire or flue. Now, I find most conclusive proof, that if we look to that the former is adequate, not only to the recipient and its heat-absorbing pro the distribution of as much heat as can perties, and attend to the interior of the be taken up by the latter, (both being boiler, and preserve all right in these re plane,) but even to ten times as much. spects, we shall do all that is practicable This is the origin of my plan of increase towards preventing injury from over ing the evaporative power of a boiler, heating, or what is crroneously termed and which consists in enlarging the outer “burning the plates."
receiving surface, so as to obtain a larger Let us now enquire what are the seve quantity of heat. With this view, I preral recipients of heat which present them sent to the action of the heated gases selves in ordinary boilers. These are:- passing through the flues of boilers a large 1. Water,
additional absorbing surface, and without 2. Steam.
adding any thing to the interior distri. 3. Air.
buting surface. The use and value of 4. Deposit crystallized.
the pins arises from the well-known pro5. Deposit uncrystallized.
perty of metallic bodies to transmit heat The two latter have already been ex by conduction. These pins I construct amined. I have now to speak of the from two to four inches in length, beyond three first mentioned, and this I will do which there can be no practical advantage in my next communication.
gained. I am, Sir, yours, &c.
Being now engaged in a series of exC. W. WILLIAMS. periments, on the large scale, on this Liverpool, February 7, 1842.
important subject, I will recur to it on
C. W. WILLIAMS. ON EVAPORATION BY CONDUCTION.
Liverpool, February 9, 1842. C. W. WILLIAMS, ESQ. Sir,-In reply to the observations of your correspondent, C. W., in your last week's Number, suggesting improve SINGULAR PHENOMENON-BURSTING OF ments on my mode of increasing the evaporative power of boilers, I fear he Sir,—The bursting of water pipes is a overlooks the main object contemplated subject that has been very fully discussed by me, which is, not to increase the in in your pages, and one that was supterior heat-distributing surface of a boiler posed to be tolerably well understood ; but plate, but to enlarge its exterior heat a circumstance has just occurred that apabsorbing surface. In fact, I require no pears to distance all our knowledge on addition to the inner surface; not on ac
this subject. count of the difficulty of removing depo By protecting my water pipes with sited matter, but because the plane inner ashes, as stated at page 19 of your 96 lst side of an iron plate is quite sufficient for Number, I have preserved them uninthe transmission and distribution of all jured through the frost; but I have a the heat that could, by possibility, be re syphon pipe, leading from my water cis.
SUGGESTIONS FOR THE IMPROVEMENT OF CANAL NAVIGATION. 121 tern into the garden, with which I took shorter leg, a pressure that would seem another course.
to be altogether inadequate to account for This syphon consists of a piece of half, the effect produced. inch drawn tin tubing, such as is used We have frequently heard of the burstby gas fitters, 15 feet long and fths of ing of gas-pipes, an idea which I have an inch in diameter externally; the always scouted, seeing that the pressure longer leg of the syphon is about 8 feet, within them never exceeds that of an the short leg about 4 feet in length : the inch of water, and yet this fact has former is led down a brick wall, to which been most confidently asserted as the it is lightly secured by wall-hooks; the cause of several destructive fires. It latter dips into the cistern. At the latter happens unfortunately in these cases, that end of October last, before the frost set as soon as the gas becomes ignited at the in, having no further occasion for any aperture thus made, the metal is almost water in my garden, I emptied the sy- instantly melted, and prevents any obserphon, but afterwards shut the cock vation being made. The positive burstwhich terminates its lower leg. One day, ing of such pipes, however, under slight last week, I attempted to refill the syphon pressure, or in consequence of some disby exhausting the air from its longer leg, integrating property of the metal of which but failing in this, I began to look for the they are composed, seems to be demoncause, when, to my great surprise, I strated by the fact which I am now defound the empty pipe had actually burst scribing.' The explanation of this pheabout 9 inches above the cock; not a mere nomenon is of infinite importance to our slit, bata palpable enlargement of the pipe, domestic safety, as proving the liability and a rupture exactly as shown in the ac to accident from this hitherto unpercompanying sketch. The only pressure ceived cause, and it also becomes desirable that I can conceive to have been operating to know whether leaden pipes are sub
ject to the same law.
The alternate expansion and partial contraction of leaden pipes, is well understood; how far tin may be subject to a like influence, and whether this will go any way towards explaining the phenomenon in question, I leave your better informed readers to explain. Any persons interested in this question are welcome to inspect the ruptured pipe, which shall remain untouched for a week or so. I remain, Sir, Yours respectfully,
WM. BADDELEY. 29, Alfred-street, Islington, February 3, 1842.
SUGGESTIONS FOR THE IMPROVEMENT
OF CANAL NAVIGATION,
Sir,-During the rapid progress of railways our canals have been less thought of, but there is no doubt but the present mode of canal conveyance may be much improved. The principal object to be gained is a quicker transit of goods or passengers, which can only be effected by the boats passing along the canals at
greater speed and by being less detained within the pipe, is that which would at the locks. It is admitted that a boat arise from a slight compression of the at a quick speed meets with less resistance air within the syphon, as the water rose than one at a slow speed. We have had in the cistern around and within the reports of several trials of boats being
propelled by steam, but we never had a (perhaps injudiciously) the term firma trial of the following plan—a towing. mental Auid, but with the express intenpath on each side of the canal with iron tion to make it understood, that the said rails, and an engine similar to our present fluid was to be found every where, except railroad, propelling a limited number of where interrupted by solid matter. In boats. Where it is actually indispensable further illustration of the description of for the canal to rise or fall, there might the medium, it may be as well to observe, be some description of lock similar to that the presence of the solid atoms in “Salt’s Perpendicular Lift,” as described the medium occasions a denser atmosphere in your Magazine, vol. xxxiv., page 465, round each atom, so that when they are which would at once move a boat from pressed together they restore themselves one level to the other, and save the great to their original distances. The tendency loss of water consumed by our present to produce stillness and compactress in locks. The engine must be either re. the cold medium, and the tendency to moved by an inclined plane and the as promote motion and diffusion in the hot sistance of a stationary engine, or pass medium, I have, perhaps, improperly ed over the canal by a swing bridge to designated freezing and heating prin. the other towing-path where it would be ciples. I am unused to discussion. By required to convey boats in the contrary a chemical change, I mean a variation in direction, and another engine might be the disposition of atoms, which occasions in readiness on the other level to con a variation of sensation. tinue the line of boats formed. The “ The friction attendant on life" must stationary engines would prevent the surely be an important agent in the conlocks being stopped by frost in winter. version of the cold medium into the hot Where tunnels were actually required, medium. Whether a man be passive as there must either be a stationary engine an Esquimaux, receiving his last gulp of or towing-paths through them. "A canal
blubber from the fair fingers of his lady, with a single towing-path would be more or alert as the conductor of a steam train; economical. The above plan would offer whether he be simple as a new-born babe, a delightful trip--no concussions or un
or “ wise enough for fools to think him pleasant motion in travelling, and less mad;" whether he earn his bread by the work for coroners and jury-men.
spade, or the “frictioning about” of the GESTATOR.
harlequin,-I have not the least doubt that Liverpool, Feburary 3, 1842.
every state tends to the benefit of the whole. As long as he draws his breath,
the “friction attendant on life” will perE, A. M.'s NEW THEORY OF THE UNIVERSE form its office. What, if 800,000,000 -EXPLANATION OF TERMS.
of human beings, &c. were destroyed Sir,-In reply to the remarks with at the deluge; can any one look at a which Mr. Pasley has favoured me, I can glass of water through the solar microonly say, that I shall always be ready to scope, and imagine that this would occaadopt any term that may be deemed pre sion a scarcity of animal life? A little ferable to my own, as soon as I am sa difference perhaps in the method of pertisfied that it fully expresses my meaning forming the same operation. In accordance with my theory, the me All theories appear easy to the mind dium of space would consist of a simple that forms them. Mine assigns a purer medium with solid atoms differently dis element for organic nature than exists posed, as explained in your 963rd Num elsewhere, consequently, a becoming seat ber, and that it is only in communication for life; while it at the same time conwith organic matter that a different dis verts a condensing power into a diffusive position of the atoms with the medium one, the whole being of course in a state occurs. In
The maI used the term firmamental fluid to ex chinery of the universe, materially, appress the original light which was first pears to have been completed on the fifth created, and which required to be re-con day; consequently, the existence of man structed by the sun to adapt it to the eye. was not necessary to the motions of the Earth and heaven, in a material view, solids of the universe. only mean body and light. As the word I have neither ambition nor conceit: I light has so many meanings, I chose am fully aware of the disadvantages un