US11883A - Improvement in surface condensers - Google Patents

Description

UNITED STATES PATENT OFFICE.

XVILLIAM SEIVELL, OF BROOKLYN, NEIV YORK.

IMPROVEMENT IN SURFACE CONDENSERS.

Specification forming part of Letters Patent No. l 1,883, dated October 31, 1854.

T0 all whom it may concern:

Be it known that I, VILLIAM SEWELL, en gineer, have invented certain new and useful Improvements in Surface Oondensers; and I do hereby declare that the following specification, taken in connection with the drawings, is a full and fair description thereof.

Figure l is a section through the center of a surface condenser, showing the water-spaces at the end of the tubes, proper entrance, and

discharge-apertures, duc. Fig. 2 is an end View thereof with the half of the head removed, showing the guard which prevents the tubesn from creeping. Fig. 3 is a section through the tube-sheet in the line A B of Fig. 2; and Fig. l is a section on a larger scale through some of the tubes, a portion of the metallic tube-sheet, the elastic tube-sheet, guard, dac., showing clearly the shape that the elastic tube-sheet assumes when in position.

The advantages incident to the use of surface condensers in marine engines and those whose boilers are supplied with impure Water are so well known to engineers that I do not think it necessary herein to describe them. The difficulties attending their successful employment are also well known, and consist, iirst, in their liability to leakage, which renders the condensers unserviceable when it takes place to any greatextent, and, secondly, in the impossibility of repairing the condenser and making it again serviceable at sea after the occurrence of such a leakage. This leakage arises chiefly from the unequal expansion and contraction of the tubes as coinpared with the variations in length of the shell of the condenser. The tubes are thereby caused to move endwise in the tube-sheets and soon abrade their flanges or else tear themselves apart. As there is a difference of pressure of from twelve to fourteen pounds between the inner and outer sides of the tubes, small leaks must of necessity discharge large quantities of water, and the steam-space rapidly fills up with water, rendering the whole condenser useless until thoroughly repaired. The long and patient experiments of Hall upon marine surface condensers and their final abandonment have fully developed these facts and have led to many ingenious inventionswhose object is to obviate these difiiculties.

My invention has the same object, and the nature of the iirst part thereof consists in se curing the tubes or their equivalents in the tube-sheets in such manner that they are free to expand and contract and slide in the sheets,

While the joint between the exterior of the.

tube and the sheet is packed perfectly tight, this object being effected by a supplementary tube-sheet ot' elastic material--india-rubber or gutta-percha or their equivalents-applied substantially in the manner hereinafter described.

The nature of the second part of my invention consists in a method of" preventing the tubes from creeping out of their seats while tree access of steam or water is permitted to their interiors.

The nature of the third part of my inven tion consists in so constructing the guard above described that it will also perform the duty of holding down the edges of the elastic supplementary tube-sheet.

The nature of the last part of my invention consists in combining with a condenser whose steam-space is outside of the tubes a secondary or supplementary injection-pipe arranged in such manner that it will distributc injection-water over the outside of the tubes, whereby the condenser may be used as an ordinary jet-condenser in the event of any unforeseen accident or injury to the tubes or their tube-sheets.

In the drawings I have represented a condenser in which the cold water is passed, forced, or drawn through the tubes, and the steam-space is outside thereof and between their exterior and the shell. This arrangement of tubular condenser is preferred by me on many accounts, and is nearly as well known to engineers as that arrangement in which the steam passes through the tubes. The former plan obviates all danger of the choking of the tubes by grease, which often occurs when the latter arrangement is applied in practice, and also admits of an easier and more equable diliusion of the steam,per mitting it to fiow without obstruction to such portion ot' the condenser as may for the time being be thecoolest. The first and second parts of my invention are, however, equally applicable to the other arrangement.

In my condenser the tubes are passed each tube where it enters the india-rubber forcing it outward in such manner that the latter clasps or hugs the tube closely for a short distance cylindrically and then recedes gradually from the tube until it coincides with the general plane of the metallic tube-i Y sheet.

When water is permitted to press upon the elastic tube-sheet, it forces it firmly down upon the metallic sheet and causes it to hug more Ycloselyaround every tube, completely preventing anyleakage between the peripheries of the tubes and the metallic tube-sheet. Each end of each tube is thus secured, and it is obvious that the tubes are free to slide in their tube-sheets without liability to in- -jury or strain, the joint at the same time being preserved. Any tube, moreover, can be removed and replaced with facility, thus giving opportunity to clean a foul tube or renew a worn out one, such removal or replacement being effected without theexerciseof any great mechanical skill by any ordinary engineer. Actual practice proves these points, and the only danger of a leak would be from Water entering under the outer edges of the elastic tube-sheet, equalizing the pressure on both sides thereof and permitting it to rise from the metallic tube-sheet, when the Water would flow through the metallic tube-sheet around the tubes. To meet this difficulty I have applied around the edge of the elastic tubesheet a ring of metal, which, by means of screws or clamps or their equivalents, is forced down upon the india-rubber, confining its edges closely to the metallic sheet. In this Way the water is prevented from passing behind the india-rubber, and itis (when the condenser is in use) held down in its place by a pressure varying from twelve to fourteen pounds upon the square inch.

In practice it would be almost impossible to make each end of each tube bear with lequal friction upon either the metallic or the elastic tube-sheet. The tubes, therefore, either in expanding or contracting, would tend to creep continually in one direction, and'would iinally unseat themselves at one end or the other, thereby causing a disastrous leak. In order to obviate this difficulty I have adjusted over both ends of each tubesheet, not touching them, a metallic sheet pierced with holes, ora grating or series of bars so constructed that it will not obstruct the passage either of water or steam,but will prevent the tubes from creeping beyond a certain distance; and with a View to economize space and expense of construction I have so shaped and adapted the guard that it also constitutes the ring which holds down the edges of the. elastic tube-sheet. I have thus provided against all accidents that appear possible; but the condenser, especially cfa marine engine, is so important a feature that it is necessary to provide against even a remote chance of any accident that would render it wholly unserviceable, as its loss at once detracts nearly one-half from the power of the engine. IV have therefore contrived an arrangement by which the condenser lnay almost instantaneously be converted into an ordinary jet or showering condenser in which the condensing water is mixed and drawn oif with the condensed steam.

The same letters refer to the same parts in all the figures, and the tubes are shown at t t t, they being in this instance s0 calculated as to site and number that the area included between their eXteriors and the shell is just double the area of the space Within all the tubes. The metallic tube-sheets are shown at m. s m s and the elastic ltube-sheets at c s e s. The guards are shown at g g, and upon their peripheries are formed rings r r. which by means of the tap-bolts?? b t Z7 are firmly compressed upon the elastic tube -sheets The entrance for the exhaust-steam is represented at e, and the apertures for the entrance and discharge of condensing Water at c c. This wat-er may be forced in and distributed in any of the known ways bypumps or bythe passage of the boat through the water, orotherwise, and it may, if deemed necessary, be caused to flow more than once through the Vtubes by means 0f proper partitionsarranged in the spaces s s. In some casesI intend to apply several pipes, dividing the whole stream of Wat-er into several parts and to arrange in the entering space partitions which shall cause each stream of water to flow through its own set of tubes, thus equalizing the flow and consequently the temperature in each portion of the condenser. I also intend sometimes to locate inside of each tube a bar of metal or wood, nearly or quite as long as the tube, whose axis shall coincide with that of the tube, such bar filling about half of the space Within the tube, and thereby causing a given supply of water to pass more rapidly vand in more immediate contact with the interior surfaces of the tubes, thus obtaining a greater amount of cold from a given lquantity of Water. In some instances it may be convenient t0 divide the elast-ic tube-sheet once or oftener, in which case the ring must be so shaped that it will hold down the edges of each separate piece of india-rubber or its equivalent. It

may also be convenient in some cases to use ILSSS V 3 an elastic tube-sheet thicker in proportion than that represented in the drawings, in which case the holes through the same must be more nearly equal in diameter to the outer diameter of the tubes, and the cylindrical portion of the elastic sheet will be shorter, or may sometimes entirely disappear.

At t' t' are represented apertures closed by stop-valves of any known kind and connected with an ordinary injection-pipe. At 0 is shown another aperture, which is connected in any appropriate manner with the air-pump, and the condensed steam is here drawn od.

The shell of the condenser herein represented is cylindrical. It may, however, be

constructed in any shape deemed most con-v venient. I have, moreover, put the whole together in a simple and convenient manner, affording every facility for the taking out, replacing,or cleaning of the tubes. The whole, however, may be constructed as tubular condensers now are, my elastic tube-sheet being applicable to any known form of tubular condenser. As the tubes are free to move in the tube sheets, these latter are unsupported, except at their peripheries, and are exposed to a pressure depending upon the amount of vacuum in the condenser. This pressure would, unless resisted, probably fracture the sheets, and to guard against such a contingency I have cast ribs upon their inner sides, in which. are tapped screw-holes h h, and in these are inserted bolts b b, with right and left handed screws cut upon the ends thereof. By turning these bolts they can be made to bear any portion or the whole of the pressure upon the tubesheets. These bolts are arranged in spaces formed by leaving out rows of tubes, and these spaces also serve as free passages, permitting the steam to pass rapidly through them and then equalize itself among the tubes. This arrangement insures an equal supply of steam to all the tubes and renders the whole condensing-surface available. These tubes may with a very good result be fastened in one of the tube-sheets in any of the ordinary ways, while they are secured in the other by means of my elastic tube-sheet, it being evident that they will have even then ample room for expansion and contraction without chance of rupture. As my method of securing the tubes is, however, not only tighter, but less costly, it is probable that it will be generally applied to both ends of the tubes.

The operat-ion of 'the condenser is as follows: Water enters at c and is discharged at c, circulating through the tubes, and steam enters at e and is condensed upon the cold surfaces of the tubes and drawn oh, by the air-pump through c. In case of great leakage and. consequent choking or drowning of the condenser the supply of water through c is shut off and both it and the discharge-apertures are closed. The stop-valves on t 'L' are then opened and water enters through the apertures t" yt", falling in a shower over the tubes, dropping from tube to tube and mingling with and condensingythe steam.` The every respect an ordinary jet-condenser, stillkeeping up a vacuum and ceasing only to supply fresh water.

I have throughout described the water as inside and the steam as outside of the tubes; but if it should be desired this arrangement may be reversed, it being necessary in such event to place the elastic tube-sheet on the inside of the metallic tube-sheet, as clearly shown by dotted lines atx a: as, and to secure the ring on its periphery, as shown at y y. The guards must remain in their present positiou, and the steam-passages will become entrances and dischargers for water, while those now supplying and discharging water will receive the exhaust-steam and discharge it when condensed. In this case the shower ing-apertures are rendered useless and the condenser cannot be converted into an ordinary jet-condenser.

The advantages secured by my method of packing and securing the tube ends and preventing leakage are still retained. The tubes in the condenser, if made of copper, may be covered inside and out with a thin coat of tin, or block-tin tubes may be employed.

I have throughout this specica-tion spoken of the elastic tube-sheet as made of indiarubber, gutta-percha, 0r some equivalent thereof, and mean, of course, that such elastic substance shall be vulcanized or in some manner be so prepared as to be proof to a suiiicient extent against the action of heat.

I do not enlarge upon the merits of my method of preventing leakage and creeping of the tubes, believing as I do that the simplicity and perfect security of the methods are obvious. It is also worthy of note that the plan of securing the tube ends is also less expensive than any plan now in use, and cheapness in an article of so great cost as a large condenser is no slight advantage.

Having thus fully described my improved surface condenser, I claim as ofmy own invention, and desire to secure by Letters Patent of the United Statesl. The elastic supplementary tube-sheet, constructed and applied substantially in the manner and for the purposes herein described.

2. The method, substantially as herein described, of preventing the endwise sliding or creeping of the tubes.

3. So constructing the guard that it performs, in addition to its own duty, the further ohice of holding down the edges of the elastic tube-sheet, preventing the entrance of water behind the same, substantiallyin the manner herein specied.

4. T he injection or showering apertures, in combination with asurface condenser whereiu the steamspace is outside of the tubes, and'which is also provided Wit-h proper entra-nces and dischargers for circulating Water through the tubes, whereby a surface condenser may be converted at will into a. jetcondenser, for the purposes and in the manner substantially as herein described.

Ih witness whereof I have hereunto subscribed my name on this 22d day of October,

WILLIAM SEWELL. Witnesses:

SYLVESTER LAY, HENRY B. RENWICK.

Images