US1303758A - Marine boiler - Google Patents

Description

J. E. BELL.

MARINE BOILER. APPLICATION FILED MAR- h 1918.

1 1,393,758. Patented May 18, 1919.

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J. E. BELL.

MARINE BOILER. APPLICATION HLED MAIL 191's.

Patented May 13, 1919.

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INVENTOR J. E. BELL.

MARINE BOILER.

APPLICATION FILED MAR. 1. 191a.

Patented 1 1 13, 1919.

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J. E. BELL.

MARINE BOILER.

APPLICATION FiLED MAR. 1, ma.

Patented May13,1919.

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J. E. BELL.

MARINE BOILER.

APPLICATION man MAR. 1. 1918.

1,308,758 Patented May13, 191g 1 SHEETS-SHEET 5.

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MARINE BOILER.

APPLICATION mac MAR. 1, ms.

Patented May 13; 1919.

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UNITED STATES PATENT OFFICE.

OHN E. BELL, orrnooxnyiv, NEW YORK.

MARINE BOILER.

To all whom/ct may concern,

Be it known that I, JOHN E. BELL, a citizen of the United States residing at Brook- 'lyn, county of Kings, and State of New avoid all complications in lts. design, so as to bring its manufacture within the scope of the facilities ofjordinar-y makers ofsuch ap paratus, and to increase tothe utmost possible limit itsapractical value and efficiency;

I have therefore devised such a boiler in the form which I have illustrated, in the accompan'ying. drawings. It is one that cannot claim distinction from existing forms, except in certain particulars, along very radically new lines, but which -1s characterized by improvements, mainly in details of construction and mode of operation with regard to whichno broad statement of their nature and purpose will serve any useful purpose in indicating those features ofpatentablenovelty' which it embodies and in= vo1ves.; I shalltherefore describeimy improvements somewhat specifically, by reference to the. accompanying drawings, pointj as ing out,as convenient opportunity presents, those novel features which constitute ader parture from preexisting forms.

Figure-1 is a'view front elevation of a complete marine'boiler an'd casin constructed in accordance with my inventlon;

Fig.;,2 is a view in elevation o-f-o-ne side of the boiler, with parts of the casingremoved to exhibit the relations thereof of a superheater. i

Fig. Eris-an enlarged'view in elevation of a. portion of the casing illustrating details of constructionenterin into the same. i

Fig. 4 is an enlarge sectional view ofa part of the c si g and parts of the interior or boiler proper. f

Fig- 5 is avertical cross-sectional? view of the complete-structure. I

Fig. 6' is a similar cross-sectional view but atrightang'les'to. the plane of Fig. 5.

. Fig... 7 is an enlarged sectional view of a detailentering; into the construction of one of the: boilerheaders.

Specification of LettersfPatent. P t te M 13, 1919, -.B.pp1icationfiledillltarchI.1918. Seria1No,219.924.

7 section of the portion of the boiler at one end. of the tubes, to show-the disposition of the latter, with reference to each other and to certain-hollow bolts through the headers, by

the use of which the tubes are cleaned.

Fig; 10' is a detail of a modifiedarrangement of the tubes and stay bolts.

, For a general understanding of the construction of the boiler asa whole reference may be had to Fig. 6. Thisboiler is provided with a proper setting 1, the walls being built up in any suitable manner, and is placed over a fire box 2, also .of the usual character. The boiler proper iscomposed-of two. continuous box shaped headers 3 and 4:, connected by straight tubes 5, inclined forward at an angl of 18 to the horizontal.

The steam andwater drum 6, is connected by nipples7,fwith the front header 3, and by circulation tubes 8,. with the rear header, which last named tubes. are in two rows, expanded' into the drum aboveand' below the center line respectively, and at the other end 7 slightly bent so as to: enter the rear header normally. Opposite each boiler tube 5, and in the outer lates of the headers3, are hand holes with s ightly beveled sides, which are closed by conical plugs 9, and. drawn by nuts 11, with a force that presses a soft metal seat or gasket with which these devices are usuall furnished to the shape of the opening an prevents further advance of the plugs. The header plates 13 and 14:, as shown in Figs. 6 and 7 are connected by hollow stay bolts'l2, and every other tube 5 is'left out of the second row and every other alternate row, as shown in Fig. 5, opposite the points occupied by the stay bolts; By this means each hollow stayv bolt. is at the center of a cluster of six boiler tubes, and affords a very effective and convenient means for cleaning or dustingthe tubes, by the introduction of a steam orair lance 15, through said bolts as indicated in Fig.

The boiler tubes in the several rows. are spaced closet'ogether so that the gas velocity is high and little baflling is required. It will also be observed that the streams of hot gaspassing between the tubes of the closely spaced rows; expand and mix before they.

widely spaced tubes, while each close spaced tube is almost directly in the path of the gases passing through the spaces between them and the widely spaced tubes below,

The tubes of one row of each pair are placed opposite spaces inthe accompanying row, and

the stay bolts occupy a like relative position to the tubes of adjacent rows. By this arrangementthe same provision for cleaning the boiler tubes is afforded.

The tube arrangement described, in ef fect, consists of a number of screens formed by closely spacing the tubes with open spaces between them. The gases of combustion pass through the tube screens at high velocity and the temperature gradient along the' sides of the tubes is that usually met with in boilers of the cross-pass type. In the open spaces the gas streams intermingle, due to the creation of eddies and the lowering of the velocity of flow so that the temperature gradient is destroyed and the gases are at a uniform temperature and contact with the next succeeding row withthis uniform temperature established. Thus a very stee temperature gradient acts on the lower sides of the tubes, or the points of first contact, which results in a more rapid transfer of heat than is obtainable from a uniform flow with the attendant temperature gradient. The difference between the ordinary and this new means of heat transmission is somewhat analogous to the action in mechanics of an ordinary force and forces due to impacts.

The boiler is' supported by lugs 16 riveted to the sides of the headers near the bottom as shown in Figs. 3 and 4. These lugs I6 restin cradles 17 carried by the box like casing 18 which surrounds the furnace. The boiler proper is surrounded by and inclosed in a casing 19 which is boltedto pads 20 riveted to the headers so that the boiler and its casingform a single rigid structure.

This construction has many important ad vantages. The casing is very materially stiffened so that no cross bracing which, under ordinary circumstances-is necessary, is required. The casing is completed by the addition of two inches of suitableheat insulator 21 and two inches'of' fire brick 22 around thetubes,while that portion of the casing which surrounds the furnace is lined with three inches of insulation 23 and nine inches of fire brick 24, V 7

At about the center of the bank of tubes 7 two short baffles 27 and 28.

5 an open space is left to permit the installation of a superheater 24, the tubes of which run at right angles to those of the boiler.

Under this superheater there is a baifle 26,

Fig. 6, and above it at front and back are These baflies together with a plate bailie 29 over the top of the bank of boiler tubes, with openings at front and rear, as shown in Fig. 6, and two tile deflectors 30, immediately above the bottom row of boiler tubes direct the hot gases in a sinuous path through the bank of tubes, the direction of travel, in the main, being at right angles to all the tubes.

With the remaining structural details this application is not especially concerned. It may be stated that the casing is provided with the usual and necessary doors for inspecting the superheater or for gaining access to the interior of the furnace; that any proper means may be used for opening, closing or securing such doors; that provision may be made for burning either coal or oil under the boiler, and that the plan of pipe connections between the boiler tubes, drums and superheater may be such as is ordinarily employed or as necessity may require.

It remains therefore to point out more 7 closely together as the metal in the end plates or headers permits, with the result of greatly increased efficiency and a marked reduction in the space occupied by a boiler of given capacity. It would be impossible to get a steam lance into the boiler from either side with this close spacing of the tubes, but the close tube spacing together with the stay bolts affords a ready means of cleaning.

There is a peculiar and marked advantage secured by the special system of 'baiiiing, which is of such a character that the gases are forced to pass over all portions of the heating surfaces while at the same time the retarding effect on the draft is reduced to a minimum. he baffling used naturally leads to the locatlon of the superheater in the po-- sition shown. It will moreover be observed that on either side of this superheater is a space constituting a secondary combustion chamber in which the gases have a chance such as is provided for in this design on both sides of the superheater. In the ab sence of secondary combustion chambers of this sort, flaming'occurs in'the uptake and the efliciency of the boileris reduced. Fur thermore, these open spaces establish a uniform temperature in the gases so that they contact with the superheater tubes with a steep temperature gradient. The gases enter the superheater from two sides and at right angles to the tubes so that when the surface of the tubes is composed 'of Foster rings, or corrugated, it will be thoroughly and effectively swept by such gases.

The feature of attaching the casing solidly to the headers of the boiler is also of importance as the headers constitute girders of the greatest stiffness whereby a very rigid casing is afforded with the minimum of space.

The special arrangement and close spacing of the boiler tubes, it may be further stated,

. has certain peculiar advantages. It is well known that the rate at which heat is absorbed from a hot gas by a cooler surface,

is almost directly proportional to the velocity of the gas over that surface, or more strictly speaking, to the product of the velocity and the density, or what is known as the mass flow. To secure this high velocityit has been customary to insert in boilers baflies which have a tendency to increase the length of the path of gases from the furnace to the gas outlet. It has, moreover, been demonstrated by experiment that when the gas passes over the tubes in a direction at right angles to their axes the absorption of heat is at a greater rate for a given velocity than when the gas travels along the tubes, as a result in the most efficient form of boiler the baffles are arranged to secure a transverse passage of the gases, but this usually involves the forcing of the gas to make two or three complete and abrupt turns and is accompanied by a loss of draft. If this loss be too high the capacity of the boiler is reduced, so that the ideal arrangement of battling is that which gives the maximum of heat absorption with the minimumof draft loss.

In the boiler herein shown and described a high velocity of gas travel is secured by spacing the boiler tubes close together rather than through the baffle arrangement. The" thereby, and a casing surrounding the tubes and headers rigidly secured to the headers.

2. A marine boiler comprising a bankof straight tubes, continuous box like headers joined thereby, and a covering or casing surrounding the tubes and headers and rigidly secured to the headers.

3. A marine boiler comprising a bank of straight tubes, continuous headers joined thereby, a casing surrounding the tubes and headers and rigidly secured to the headers, and supports for the boiler formed by lugs secured to the headers neartheir lower ends, and cradles attached to the metal casing in which said lugs rest.

4. A marine boiler comprising a bank of tubes, continuous headers joined thereby and arranged above the furnace, a metal casing surrounding the furnace, a metal casing surrounding the tubes and rigidly secured to the headers, and supported upon or by the furnace casing, and heat insulating linings for both casings.

5. A marine boiler comprising a bank of tubes, headers joined thereby and arranged above the furnace, a metal casing surround- 7 JOHN E. BELL.

Copies 01 this patent may be obtained for five cents each, by addressing the Commissioner of latents.

' Washington, 10.6."

60 1. A marine boiler comprising a bank of .straight tubes, continuous headers joined

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