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The Nautilus machine, which is presented to you as the operations,—this latter the greatest desideratum of all. instrument for overcoming many of the difficulties in- These advantages must, I think, strike all, as combining herent to the nature of subaqueous operations, possesses those requisites of success which have been always wantamong others the following qualities :-It is entirely in- ing in the present known means for constructing works dependent of suspension ; its movements are entirely de- under water. pendent on the will of those within it, and without re- The form of the machine is not arbitrary, but depends ference to those who may be stationed without; it entirely on the nature of the work to be performed, possesses the power of lifting large weights, per se, and at adapting itself to the various circumstances attending any the same time is perfectly safe, by common care, in its given position. By reference to the annexed diagram you

SECTIONAL VIEW OF THE NAUTILUS MACHINE.

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will perceive that when at rest, being entirely enclosed, time a cock, e, on a pipe opening from the chambers outits displacement of water being greater than its own wards, is opened, in order that, the air escaping, an unweight, it must float at the surface. Entering through interrupted flow of water may take place into the a man-hole at the top (which is closed either from the chambers. The assumption of weight of water causes a inside or outside), you descend into the interior of the destruction of buoyancy due to displacement by the mass machine, portions of which are walled off on either side, itself, and the Nautilus gradually sinks. As soon as it forming chambers; these chambers are connected at or is fairly under water, in order that the descent may be near the bottom by a pipe a,a, which opens by a cock b, quiet and without shock, the water cock, b, is closed. outwards to the external surrounding water. An opening The receiver at the surface, being previously charged by in the bottom of the machine of variable dimensions is the air-pump to a density somewhat greater than that of closed by a door or doors, susceptible of being opened or the water at the depth proposed to attain, one of the closed at pleasure. The chambers X, X, are likewise con- branch cocks on the pipe, cc, connecting the chambers at nected at top by a smaller pipe c,c, which opens through top, is opened, and the air rushes into the working the top of the machine, and to which opening is affixed chamber, gradually condensing until a density equal to a flexible pipe, with coils of wire spirally enclosed. the density of the water without is attained; this is Branches on this latter pipe d,d, allow also communica- indicated by proper air and water guages, ff. These tion with the larger or working chamber.

guages marking equal points, shewing the equilibrium of At the surface of the water, placed on a float or vessel forces without and within, the covers to the bottom, 9.9, for the purpose, is a receiver of variable dimensions, to are removed or raised, and communication is held with which is attached at one end a hollow drum or reel the bottom on which the Nautilus is resting. In order to to the barrel of which is affixed the other end of the move about in localities where tides or currents do not flexible pipe a, leading to the top of the Nautilus. At affect operations, it is only necessary to step out of the the other end of, and in connection with the receiver is bottom of the Nautilus, and placing the hands against its a powerful steam air-condensing pump. This combina- side the operator may move it (by pushing,) in any direction represents the Nautilus machine as adapted to en- tion. Where currents or tides, however, have sway, it gineering work.

becomes necessary to depend upon fixed points from which As to the modus operandi.The operator, with his movements may be made in any direction. This is acassistants,enters the machine through the top, which is then complished by placing in the bottom of the Nautilus closed. To descend, the water-cock b is opened, and the stuffing boxes of peculiar construction, k,k, through which external water flows into the chambers, X,X; at the same cables may pass over pulleys to the external side, thence

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tion of least resistance. At each successive moment of vice, either to examine the bottom previous to the locaupward movement, the impelling power increases, owing tion, or to commence the foundations at once. to the increased disparity between the pressure of air To speak now of that portion of the machinery which within struggling for escape, and the water without remains at the surface: It is necessary in order to preventing that escape. The machine thus situated rapid movement, that the supply of air which, acting on becomes a marine rocket (in reality), in which the pro- the water in the water-chambers, causes the developpelling power is exhausted only when the surface is ment of the lifting power of the machine, should be in reached, and a new equilibrium is obtained. It will sufficient quantity, so that no delay may arise and that readily be seen, that were this difficulty not overcome, a constant supply inay be continually afforded, that there it would be impossible to govern the Nautilus; for, rising may be no diminution of density in the receiver. It is with great velocity to the surface, the machine is carried also necessary that the density of the air in the receiver above its ordinary floatation or water-line; a little more should at all times be greater than that of the water at air escapes owing to the diminished resistance, as that the depth to which the machine descends, so that the level is passed ; the recoil, or surging downwards, causes superior pressure of the air may produce instantaneous a condensation of the air remaining in the chamber; a movement of the water. A proper proportion of density portion of the space previously occupied by air is as- in a receiver would be about one-third greater than that sumed by water, the buoyant power becomes less, the of the water. machine settles slightly more by condensation of the The amount of air continually required for the respiair, a larger space is occupied by water, and the Nautilus ratory purposes of the operators, and also for the purpose redescends to the bottom with a constantly accelerating of lifting weights, demands a large supply, which is obmovement, seriously inconveniencing the operators by tained from the steam-condensing pump directly to the filling more or less with water according to the depth. receiver. The air-pumps are constructed to throw any For many months the difficulties just enumerated baffled required amount of air, each sufficient if required, to all attempts at control. A weight attached could be work two or three, or even more machines engaged lifted, but the instant it was entirely suspended, before in lifting heavy weights. the valves could be closed, upward movement was com- There is no heating, owing to the rapid condensation municated entirely beyond control. This difficulty so of air at high density. The pumps will work confatal, has been overcome by an arrangement of the tinuously at the highest density, without any perbottom of the Nautilus, with channels which radiate ceptible increase of temperature. The economy of workfrom the opening in an inclined direction, debouching at ing several machines from the same or different rethe sides of the machine. The moment then, that the ceivers, supplied by one pump, is great, as the saving of air, by its expansion from diminished resistance, or by labour, fuel, wear and tear, in one engine over several, the introduction from above of a greater volume than is quite apparent; which economy is due in part to the can be sustained by the water below, reaches in its independence of suspension, allowing the receiver to be downward passage, the level of these chambers, follow- placed at any convenient point, even quite distant from the ing the direction of least resistance, it passes through * Nautilus,'' inasmuch as the pipe may be supported on these channels and escapes into the surrounding water, the surface of the water to the point over the work without of course affecting the movement of the machine itself. in the least.

Having the powers of air and water then at control, to I have thus, I trust, shown to you the principles on obviate the use of platforms, trucks, and carriage-way, which the engineering facilities of the nautilus depend. I to lower stones into place, so that they may be properly

First, on natural principles, from construction, it deposited, you may readily see that a caisson or float, must be independent of suspension; and here allow me properly arranged with regard to the relative contres of to bring forcibly to your minds the distinction between gravity and buoyancy may be moved over or near the a machine which, by its own power, may descend, as work. A load of stone, according to the capacity of cend, move horizontally, lift weights, and transport the caisson, may be placed upon it. Having this them by itself (for I assume the operator to be a part of caisson so arranged by divison into chambers, that the machine), and the ordinary diving-bell so long the water cannot flow from side to side, and conused, by which we are enabled to perform the same structed with water valves and a connection with the operations, after much time spent in the preparation of receiver, when the load is properly placed upon it, and piling, platforms, scaffolding, carriage-way, &c.; and the water-valves opened, it will commence to sink. where all necessary movements in the prosecution of the Regulating its descent slowly by the same process as the work must be made at the surface through the inter- Nautilus itself, but governed from above, it may be vention of signals, which in all cases must be more or placed in proper position, so that the least possible disless liable to error and misunderstanding.

tance will be required to be passed over, in removing the Supposing the same skilled and careful men to be stones so lowered to their ultimate position placed under both conditions, the one time in the nency. As the weights are removed, it is obvious that ordinary diving-bell, where, when they have deter-more water will be required to be admitted, in order to mined on the necessary movements to be made, they retain the caisson at the bottom or on the work. The signal to the surface, and await, first the proper under- whole load being removed, to return to the surface, it understanding of their wishes, and then subsequently, I will be merely necessary to throw from the receiver at their execution by those who cannot know precisely the the surface a portion of condensed air, to cause it to rise amount of assistance required; or another time, in a preparatory to its receiving a new load. machine possessing the capabilities heretofore enu- The comparative cost of lowering away stone in this merated, by which the operator, having his work directly manner, as contrasted with the ordinary crane, can before him, watching all the varying circumstances hardly be doubted as being favourable to the first mewhich await his progress, foresees and applies directly thod, inasmuch as water is valueless, and the supply of his own hand to the work, governing and directing in air required to expel that water, as delivered from the person those operations which he requires to be per-condensing pump, can bear but a slight ratio of cost to formed-certainly the balance must be all in favour of the labour required to work the cranes. The cost of the latter position.

working a steam-condensing pump sufficient to lower Another thing in the case of the ordinary diving-bell, ) as many stones as would supply two machines, as well much time is necessarily consumed in making the neces- as working the machines themselves, would not be more sary preperations to commence the use of the machine ; | than thirty shillings per diem. in the other case, when once arrived at the spot re- Where water transportation of material is afforded, quired (if in the water), it is ready for immediate ser- the caissons themselves may be used as the means of

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transportation of the stone from the quarry to the site depend on the distance apart of these two centres ; thereof the work; and then fulfilling their real purpose, of fore I may say, in a properly constructed machine an depositing their load in the bottom. A great facility overturn could never be experienced. afforded by this process is, that there must always be a This is a very important subject to be considered, for supply of material below, in advance of the require- as there is no chain or rope to cause return to the surface, ments of the adjusting machines, so that no delay can unless this point were thoroughly guarded there would arise by waiting for materials.

be no safety at all, since if the Nautilus once received an For removal of rocks: the facility that is afforded by inclination by the escape of air from the upper side and going down directly on the bed of the rock, there dril. entrance of water on the lower side, the movement would ling a series of holes, subsequently charging them, and increase until the whole might be overturned. then exploding them connectedly, would seem to be It would be unadvisable to say that any given amount almost equal to that of the quarry. If large masses be of work could be performed by the Nautilus machine in detached, camels inflated, or charged from the receivers a given time under all circumstances. The power of the may be affixed to them (if too large for the nautilus it machine is positive, and can be certainly relied on; but self,) and when lifted, towed to the place of deposit, and it may not always be possible to exert that power to its there left.

full extent. The length of time required to submerge Manual labour alone can now be used below water; a first-class machine, lifting six tons, will be two and onefor steam, our great substitute, cannot be passed through half minutes. Going down slowly, sixty feet per so great a length of hose, and through varying tempe- minute may be attained. While the machine is descending, rature, as is necessary, without condensation, but air the working chamber may be filled with air of the proper does not change its density by passing through great density to resist the entrance of water when the bottom distances, or by any moderate change of temperature. cover is removed. Two minutes are sufficient to un

Having a supply of air at the necessary density for a clamp and raise the covers. If the object to be raised motive power, it may then be used as such, to propel be immediately beneath, as soon as the necessary conthe necessary drills for boring rocks, by having the pro-nections can be made, the water cocks are opened and per engines placed within the “Nautilus,” and exhausting the air is thrown into the water chambers, which can be to the surface. Air being at the same density as steam, entirely emptied giving its full lifting capacity of six and contained within the receivers, which are atmospheric tons in one-and-a-half minutes. boilers, we may apply the powers of air below, the same As to movement horizontally.--Every practical mind as steam at the surface, to the performance of any labour can form its own conclusions, as to the rapidity with which may be required. There is no difference between which such a buoyant mass could be moved through the air and steam at the same density in their application, water. An extract from the report of Mr. Gay, Chief except that in the use of air, which is a more subtle fluid Engineer, U. S. Navy, to the Bureau of Docks and than steam, we must exercise additional care in the ar- Yards will verify the statements I have made :rangement of valves, &c. The powers of air which can * * * " With the assistance of two experienced be developed at the surface in any required amount, are persons, I descended in the bell to about twenty feet not only applicable to the working of drills for boring below the surface of the water. The time occupied to rock, but for the sawing off of piles in the preparation of prepare the bell and reach the bottom was about two foundations, and for any other purpose where the appli- minutes and thirty seconds, and about a minute and-a-half cation of manual labour at comparatively high cost, to return to the surface. * * * should if possible, be obviated.

"One of several blocks of granite, weighing about four To saw off piles for foundations. If one pile be driven tons each, had been previously prepared, and placed on or cut off at the requisite level, the Nautilus, which by the bottom; the bell was attached to this stone by a construction retains its lower surface in a horizontal · Lewis.' * * The time occupied in securing the position, resting on that pile, and working a saw in the stone and coming up was about three minutes. * * * plane of that lower horizontal surface, will of necessity, I descended with the stone, and, by the aid of two men, cut all the piles with which it may be brought in contact transported it several feet laterally, with as much ease in the same plane, then preparing the grillage and plank- as it could have been done were it suspended upon a ing necessary, when lowered, the Nautilus passing over it crane, with the advantage of placing it at any point, or can cause it to be securely affixed to the heads of the in any desired position,” piles so cut off.

| By skilful and practised manipulation, the powers of It is manifest that, unless very carefully arranged, any any machinery must be developed in a greater degree submerged vessel descending rapidly, and striking on any than by unskilful handling. In acquiring the necessary projecting object, would be liable to be thrown from its skill, the necessary length of time required depends horizontal position, and to be overturned. Assume that much on the complication of the principles involved, or the ordinary bell is descending, and strikes on a project the details by which the results are obtained. In work. ing or shelving rock, lowering away from the surface ; | ing the Nautilus machine, it is not necessary that the unless the signals are distinctly understood, the chances operator should be a scientific man or practical mechanic. would be very great of an overturn, resulting in great By the absolute control of natural elements, the will of danger to those within.

the operator as it were, directs and governs the moveIn the case where no suspension exists, it becomes ments of the machine. It is thus the operations of the necessary to overcome any such tendency to danger, machine are comparatively inexpensive, since you are rewhich is done by so harmonizing the centres of buoyancy quired to pay for labour alone, and not to compensate for and of gravity, that under no circumstances can there be the genius to comprehend or the skill to control a combut a very slight deflection from a horizontal plicated and delicate instrument. position. Gravity acts downwards and buoyancy up In any paper description of a new system, of whatever wards, both in vertical lines. Construct a machine nature it may be, it is impossible to enter into sufficient symmetrically, then, with the centres of gravity and buoy detail to enable the mind at a single glance, or by a ancy in the same vertical line, the one near the bottom, single hearing, to fully comprehend all or even most of on account of weight, the other by peculiarity of con- the advantages claimed, or of the disadvantages which struction, as far removed as possible from the first, or as may be found apparent. In the case however of the system near the top as may be. If, by any means the horizontal which I have the honour of presenting to you, as applied position should be destroyed, both forces at once act to to submarine engineering, based as it is on purely natural restore its original or correct state, gravity downwards, principles, whose partial application heretofore has been buoyancy upwards; and the power or effective lever attended with a degree of success, certainly of a satiswhich tends to restore it to this horizontal state, will factory character, the principles laid down I trust, are

so easily understood that no one can fail to admit that, then be signalled to work, to restore the volume of air certainly if the principles in their adaptation in the Nau- / and drive back the water. Oscillation too is dangerous, tilus, are governed as represented, the value of the im- if at all of a serious character, for the masons may be provements thus made must be of great practical impor- injured in their limbs if standing on the bottom with the tance to the engineer, by rendering his labours free from bell suspended. The mason knows too, that if the chain, much anxiety, and enabling him with confidence to on which rests his entire hope of safety should break, undertake works of peculiar characteristics of position, that the chances are almost certain that his life is lost. which, previously considered, would have seemed hazard-(numerous instances have attested this latter point); the our.

weight is too great for him to attempt to raise it, and I cannot flatter myself that in this system, a sovereign his workshop furnishes him with a metallic coffin. It is panacea has been discovered for all the dangerous symp-evident that no man, however daring he may be, can toms which the engineer meets with in the practice of work with so much will where the chances of danger, his profession under water; but I trust that you will however remote, are independent of his own power of admit, that certainly his toils may be rendered lighter, governance, as he can where he feels that his own will his risks diminished, his expenditures curtailed, his time can at any moment remove him from the possibility of saved by this process.

danger. A sketch of the construction of a work, by present pro- In reascending to the surface after the completion of cess, and by the use of the Nautilus may be permitted duty below, the movement must necessarily be very slow, me. We will suppose the location selected, and that the owing to the same reasons previously enumerated in impracticability of constructing a coffer dam has rendered lowering away. If the chain break while ascending, where necessary the use of the ordinary diving bell, which we would be the labourer's chance ? will also suppose, is already constructed and ready for use. Enough of the difficulties below. There are still

The first step will be to commence driving the piles dangers and difficulties at the surface. A storm arisesupon which the scaffolding is to rest ; the scaffolding the work is in an exposed situation—and a portion is must then be constructed; the rails must be laid for the weakened, perhaps carried away. passage of the suspending trucks; these trucks must The necessary time must be taken to strengthen or rethen be placed in position and prepared for use. The construct the damaged portions. This involves time, it bell is then suspended, and we will suppose is ready for involves expense. work, a considerable amount of time having been ex- We will now suppose a position, as the removal of a pended in this preparation. The bell is raised out of the rock, or the construction of a pier-foundation, &c., where water, the masons enter, and are lowered away. The it is impracticable to construct platforms and stagings. descent must be slow, for the weight is great, the chains A boat from which to suspend a bell must be used. Any are stiff, and manual labour is required to overcome these motion communicated to this boat at the surface, must difficulties. Then too, being open at the bottom, lower-cause the oscillation below which I have previously ing away can be effccted only as fast as air is supplied by spoken of as greatly retarding or entirely putting a stop the 'pumps from above to resist the encroachment of to operations while such motion is experienced. water. The bottom is reached and work is commenced. Take now the location where the coffer dam is adopted. Movement is necessary-signals are made by blows on the The first step is to construct the dam, which is a work of side of the bell, or by the signal cord-at the same time time, which is an expense. The dam however being the signal is made and understood at the surface, they completed and free from leakage, of course the work can commence to move the whole apparatus as directed; the then be carried on with great rapidity; but there are truck at the surface and the bell below move together. difficulties even here; springs in some cases cause diffi. It is desired to stop; before doing so, new signals are culties; leaks too, arise. A storm, by weakening a pornecessary, movements below being restricted in their tion of the dam, may cause a delay for repairs or even efficiency by the proper understanding of signals. You may demand an entire reconstruction. Of course to the wish to move slightly only, you are carried too far and mind of everyone present this is but a suggestion of some must return.

of the difficulties which in all cases, in a greater or less In the preparation of foundations where in many cases degree, attend the construction of this class of works. it is required to move often from point to point in ex There is no need of bringing them forward except to cavating or levelling, this delay becomes important. place them in contrast with any means which may mitiThe foundations, however, are prepared, and the super-gate their action in whole or in part. structure is commenced. A stone is lowered. The bell To contrast the action of the Nautilus and to see how far by signal is moved over it, and they are connected ;- by its action, as previously described, these difficulties may signal to the surface, and the weight of the bell and the be overcome, I will suppose as in the case of the ordinary stone must be raised together ;-signal again to stop bell, the location is decided on. And first, before a decision hoisting ;-signal to move in or out, right or left ;- upon that point is arrived at, you will undoubtedly removement is made ;—the spot is reached, and the stone cognize the facility which the engineer possesses by its must be deposited precisely. The mason says-a little use in descending himself, and by accurate survey deterto the right, but he cannot say how many inches and he mining the most favourable position for such location. gets too far; then by successive movements by signal he The nature of the foundation required being determined, is accurately placed and lowered away. Then to place its preparation may be at once commenced, since, towing another stone he goes through the same process. Mark the Nautilus to the spot, your workmen are ready at once the time consumed here from want of independence. He to commence work at the same time that, in the other sees the stone; he knows it must go there, in that spot, case, they commence the driving piles for the scaffolding. but he cannot himself exercise the power necessary to While the scaffolds are being erected, it is but fair to place it there, but must wait the pleasure and understand- suppose that great progress may have been made by the ing of his directions by others, who of course can only Nautilus in the construction of the work itself. I have have a general idea of his wishes.

previously shown that, being in position, but a very few In this way the work is carried on. Other difficulties moments are required for the workmen to reach the botare however, in the way. The bell suspended below istom. They then see their work and are ready to proa pendulum of variable length; if the water be rough at secute it. No signals for movement are necessary; they the surface, a swaying or oscillating movement is given wish to move an inch, a foot, a rod, it is done at once; to the pendulum, which, in its oscillation however there is no restraining influence, which is not subject to slight, disturbs the horizontal equilibrium between the their own will. When their labours are ended they air and the water, and the air escapes from the upper side, themselves return to the surface, as rapidly or as slowly and water enters on the lower side. The pump must as they please.

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