US303841A - Means for preventing - Google Patents

Description

-(N0 Model.)

G. E. HALL.

MEANS FOR PREVENTING BOILERBXELOSIONSI No. 303,841. Patent d Aug. 19, 1884.

INVEN TOR WITNESSES ATTDR-NBY UNITED STATES PATE'r trier;

ouch-on E ELYN HALL, OF, NEW YORK, U. r.

' MEANS FOR PREVENTING oursmzxprosgons.

SI YBCIFICAZPIO N forming part of Batters Patent No. 303.,4l, dated August 19, 1884.

1}) a whom, it may cmicern:

Be it known that I, Guouun EVELYN llA LL,

ofthe city, county, and State ol'Ncw York,'h ave 'uid remains constant until the whole is vaporrzed. This temperature varies with the character of the liquid, and also with the pressure of the atmosphere, ones in steam-v boilers or other closed vesselsgvith the press ore of thevapor on the surface of the liquid.

WVaternnder the normal pressure of the at mosphcre boils at212 Fahrenheit. Undc r11 pressure of sixty pounds to the square inch, a temperature of 307 Fahrenheit is required to make it boil; under one hundred and twenty pounds, 350 Fahrenheit, and so 'on,

every incrcaseot' pressure requiring a'consequent increase of temperature to maintain the boiling-point. It is a well-known fact that'if the pressure on the surfaccof ahighly-heated liquid-such as water contained in a steamboiler or other closed vessel'--is from anyeause removed the water will no longer remain in the form of water, but all or. alarge proportion of it will be instantly converted into steam. The expansive or actingforee of the steam so produced will depend. upon the nine of water presenu-its temperature, and the amount of pressure which has been re moved. Very many eonditionsoccur in pram tice which act'to lessen or decrease thepressl re acting on the surface-o t" the water in the boiler. The most common wayfis by opening thc'tlirottle or safety valve and allowing the steam to pass as: freely. Now, it" the flow of.

steam which is moving with great vcloeity he suddenly stopped by closing either the throt tlc or the safety valve, a very powerful back; thrust or percussion is transmitted through and by the steam upon the body of the steam;

within the boiler, tending to compress it, not upon the surface ol the water, but upon itself, and thereby removing the pressure from the surface ot'thc-water. As a result, the su- As nmunmmu m m, 1924. (Xoinodi-l.) f

great violence. At. such a moment the water is unusually disturbed, which also facilitates the disengagement 0f-additional steam. The great volume of steam thus set at liberty acts with a force entirely beyond that which the boiler is calculated to withstand, and as a consequence a terrific explosion ensues. The result would-be the same whether the press me upon the superheated water had been removed by exhaustion or condensation of the steam. Thus, if a large body of cold water be delivered into a boiler when the engine which receives its steam from the boiler is at rest, or ii the engine be stopped immediately after theboiler' has been filled and then suddenly started, the concussive action of the .steani above. described and the agitated orviolent 'moti on of the water within the boiler will sud steam-space and steani a large quantity of water considerably below the temperature of densation will as suddenly takeplacc, causing an explosion in the manner alreadyexplained, In ease of extremely low water;. or by reason of :inunusual motion 'of the boiler-ms by thepitehing of aship-it'cold water be injected'into thestcamspaee, a like condensation of thesteam will occur, producing a similar result. When the boiler is steaming to its fi illeapnci ty, the heat applied to the outer' surface of the shell onto the inner surface of the several :tlus'or tubes, or,in generahto the generates steam so rapidly alougthose surfaces and causes it to rise in such torrents through the water above that the presence of bubbles of steam and the active motion thereot'lii'tsthe water above its ordinary level, and it the throttle-opening is large the water will rise 'in a who-shaped massunder that opening", and is ottcn carried to the cylinder of a s teunrengine, giving what; is known as wet steam. I Themaiority of boilers, when doing their best, will throw up particles of water into the accompanies" a disengagement of steam. Any sudden diminution in the pressure on the surface of the water results in a generation of de ily bring to the surface and project into the th water previously in the boiler, aud conheated surface and transmitted to the water,

perheatcd water will burst into steam with steam-space in the violent ebullit-ion which ICO - steam not only along the several heating-surfaces, but also throughout its mass, which tends to increase the percussive effect of the great mass of steam and water thusthrown violently against the interiorof the shell, the

force of whichis suflicient to produce a rupture and the consequent explosion. When working under ordinary conditions, the interior of the shell is subject to a constant ham- IO 'mering action, which occurs by the'fiuctuatrons in pressnre,due to thein'termittent relief of pressure by induction, Ofsteam into. the cylinder of the steam-engine. At the commencement of each stroke the steam-valveis opened, and the steam flows from the boiler by an appropriate pipe into thecylinder of the engine.

- When the stroke is partially completed, the

-valve closes, and no more steam is sed during thebalanceof the stroke. Thus t e pressure in the steam-space of the boiler is alternately -loweredand raised, and'is accompanied by a similar raising and lowering of the mass of water. The percussive action thus described tends to strain and weaken 'the shell of the 2 5 boiler, often giving rise to cracks, seams, and leakage. v

My inventiomwhieh is based upon the theory above set forth,1relates and has for its object to prevent the sudden changes in the pressure 50 to which the water in the boiler is subjected underthe various exigencies of practice,- and I thus preventssteam-boiler explosions. It consists of certain details of construction, as hereinafter more fully set forth, by which one or'more barriers of metal or other'suitable material are interposed in the path of the steam in itspassage from the surface of the water to thesteamrspaoe, orfrom the steam-spaceto the point where it is to be applied, each barrier 40 having a large number of openings or perforations of sufficient aggregate area to allow the 4 steam to flowi-nto the steam-space or from the boiler with the requisite freedom, and so arranged as .toeheclithe back-thruster percussion ofthe steam,and thus prev entfl uctuations in the pressure acting on thesurface of the We;-

- ter in the boiler. By, means of the large number of perforations or openings in the interposed barriers the force is a distributed or 50. brokenup, and the steam included between the barriers acts in the manner of steam-cushions. The positiouof the barriers, which are preferably sodesigned that the sum of the areas shall be equal toor slightly greater than the 5 5' area of. the pipeor combined areas of pipes by which; the, steam leaves the boiler, is preferafbly ar rar1,-, e(1 in such a manner that there shall be considerable s'team-spacebetween each, and

I thus the back-thrusterpercussiveforce,which 6o iniordinaryboilers acts with such tremendous force, is, by means of the interposed barriers,

' gradually weakened fro'mone to the other, so.

that before reaching the surfaceof the water int-he boiler the percussive or compressing cffeet willbe entirely destroyed. This arrange- {ment will eliminate many-of the objections, as

with the steam-spaces and steam; and it consists in providing a'longitudinally-arranged pipe or pipes bent'upon itself or themselves, to form parallel arms, one of which arms. is perforated with a large number of small holes, or is provided with a largenumber o1 jet-pipcs arranged in or along the under surface of the \parallel arm, the distribution of the holes or jets being-such that the larger number are located im inediatel y over that portion of the bottom plates of the boiler which are immedibox. By this means I am enabled, first, to partially heat the feed-water by itspassage through the non perforated arm, and to insure a-unifoi'in distribution throughout the water in the boiler, and thus render the presence of possible. This arrangement also enables me from deposits or incrustations which usually form thereon, and are compacted by the con sequent hammering or percussive action, as previously described,-'the action of the jets of water being to wash the lower surface of the boiler, and tostii' up and distribute any earthy deposits which may form thereon. It also acts .to increase the circulation of the water, and the earthy matter will either be kept in soluwater-andsteam onlthe sides or upper part of the shell, where it can do no harm.

In -the accompanying drawings, forming a pafit of this specification, similarletters of reference indicate like parts, in which'.. .fFigure l is a central longitudinal section. Fig. 2 is a cross-section on the line aa of Fig. 1. Fig. 3 is a-view, partially in horizontal section, of the tube for supplying the feedwater. I 1 t -In the drawings are shown one form or embodiment'of myinv-ention, in-which repreproved design, and providedwith fi'refiues'B lel toeach other, and provided with openings or perforations; D, which may beef any numsigned that the aggregate area of the openings shall be equal to or siightly greater than the any large body of cold water in'the boiler imto keep the lower surface of the boiler'frec:

her, and are lpreferably so arranged and de ately over or which act as the roof of thefiretion'or deposited by the upward ilow of 'thc IIO sents a steam-boiler, which may be'o any ap-.

B. C (3 0 areltubes, or'pipes arranged'parah area of the pipe or opening through which the steam is-conveyedfroni the boiler. The tubes -e'nd resting upon proper supports, bolted or otherwise attached td the end of the'boiler. The tubes are in no wise attached to said sup- 0 are each closedat-one end, the said closed and is niarked 53.

thainber, and is marked 2.

.inner drum, F, arranged on the top thereof,

the said drum being provided with the open jugs or perforations G, as shown in the drawings.

II is the dome, to one side of which is attached the exit; or steam pipe I, correspond ing in its internal diameter to the orifice made in the sideoi' the dome.

.I J are the barrier-plates, having the perforations K therein, and interposed between the dome and the exit-pipe, and arranged between the lengths of the exit-pipe at previously-determined distances.

I; is the iced-pipe, formed of the two tubcs M M, arranged longitut'linallyalong the lower portion of the boiler and parallel to each other, and joined together at one end to term a continuous sinuous passage. The tube M is attached to the end of the boiler, so as to be brought in contact with the pipe from the source of water-supply. The point where the tubes are joined together is adapted to rest upon any suitable support, thus allowing for the expansion and contraction. The parallel tube M, by which the water is distributed, is provided with a large number of openings or jet-orifices, N, on its lower surface, and so arranged to distribute the streams of water upon the lower surfaccot' the boiler. I prefer to locate the greatest number of openings or orifices over that portion of the boiler under which the tire-box is located, and the number and size of said openings or orifices should be such that the sum 01' their areas shall be equal or greater than the area of the passage through which the water is conveyed to the boiler.

The steam-space in the upper portion of the boilerconstitutcs what I term a first chanr her. and ismarked 1.

The combined space in the interior of the tubes t, casting E, and inner dome, F, eonstitute what I call a second or pipe The space between the domes F and II constitutethe third chamber or dome-chamber,

This latter may communicatc directly with thestcam-valve of an engine, and. be subject to all .the fluctuations of pressure due to the intermittent consumption of the steam;,or I may intcrposc the barrierplates J, which, it used, constitute independent steam-spaces between each pair of plates. As such barrier-plates are not essential to theinvention, I will describe the invention without them.

The operation of my device is as follows: Steanrgsgenerated from the surface of the "water" in the boiler is collect-ed from thestcam- II, and from the dome throughasuitable pipe. I

in which perforated barrier-plates may or may not be used, to the steam engine or apparatus where the same is tobc utilized. Strong pulsations or alterations of pressure occurring in the outer domecliamber, owing to causes as previously described, result in drawine steam with fluctuating;- force, which depends upon the amount ot'stcam drawn from the dome chamber through the pertbrations (t in the inner dome; but the expansion in the pipechamber of the steam containcd therein re duees the violence of the pulsations or lluctuations in the pressure. These reduced fluctuations in pressure are transmitted through the pertbrations 1) into the steam-elnnnber otthc boiler proper. These successive transmissions reduce the coneussive etl'ect, so as to be practically inapprtwiable to the boiler, or, it

concussive or otherwise acting l'rom the domechamber inward has its force similarly distributed and broken. The functions of the barriers are then, first, to prevent any innuediatc or violent generation of steam when the pressure is suddenly removed from the surface of the highly-heated water in the boiler, and yet while so acting to allow the steam to llow freely under ordinary conditions of press ure to supply the demand made upon the boiler; and, secondly, to break and distribute the percussive action from without inward, caused by the intermittent action of the piston or the sudden closing of the enginew'alve supplied by the boiler, or by the sudden closing of'a safety-valve attached to the boiler itself, the steam in the chambers indicated aeting as steam-cushions to arrest the percussive force before it reaches the surface of the water.

I attach considerable importance to the first barrier being in the forms of pipes or tubes 0, which present a large extent of surface, in

described, without obstructing the ordinary access to the boiler for cleaning, repairs, &c., and without interfering in any dcgree'with the action of the satiety-valve.

In putting my invention into practice I do not limit myself to any particular construcwhich the perforations I) can be formed, as-

- of the area of tion of boiler, nor to any particular number-9r -s iz'e of the barrier-plates, nor to the number of barriers which I may interp oso.

'- Modifications may be made in the forms and proportions, provided, however, that in making any. changes or modifications the sum eperforati'ons made in any of the barriers shall be equal to or slightly greater thanth area of the pipe or combined areas of pipes or area of safety-valve conveying the steam from the boiler. Iii adding my invention .to old boilers hav-. ing a dome it is only necessary to remove the dome and to introduce the parts, as described, make the connections, and replace the dome, no alterations being required to the boiler itself.

ployed, depending upon the dilferent conditions arising in practice.

To the means, as hereinv described, for inje'cting the feed-water I make no claim inthe present application, as the same is fully shown,

deseiiibed, and claimed in, the application made by request of the Patent Office as adivisionof a thepresent application, andfiled bymeJune No claim is made in this' application to the method herein set forth of preventing explosions in steam-boilers, as it may form the subject-matter of a separate application.

I claim as-my invention- 1. A steam-boiler having two or more bar.-

rie'rs'dividing the water-space from the doinespace, and one or more barriers arranged with- 4,

in the pipe leading from the dome-space to the cylinder of a steam-engine, the sum of, the

areas of the openings in any of the said barriers being equal to or greater than the opening through which the steam is led from the 5" boiler by the safety-valve orifice, or from the dome space to the' cylinder, substantiallyas described. 2. The combination, with a steam-boiler, of r two or more perforated tubes arranged inthe- '5 upper part of said boiler and suitably conneeted to a second perforated chamber with in the steam-dome,substantially as described.

3. In a steam-boiler, the combination of two chamber within the steam-dome, and the feedwater pipe or pipes located and perforated substantially as described.

or more perforated tubes arranged in'the up- 6: per part of said boiler, a second perforated 4. The combination, with astea'm-boiler, of 6 two or more perforated tubes arranged in the upper part of said boiler, .aseeond perforated chamber within the steam-dome, a pipe or pipes for com-'eyin'g the steam from the boiler,

and perforated barrier-plates within the conveying pipe'or pipes, all arranged to operate substantially as described. I '5. Theshell A, dome H, and casting .C,'in combination with each other-and with a perforated inner dome, F, andperforated barrier 7 pipes 0, arranged to operate substantially as and for the purpose set forth.-

. GEO. EVELYN HALL.

'XVitnesses:

Geo. H. BENJAMIN, A. E. SEX'TON:

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