US2531864A - Sectionally removable and replaceable firebox for furnaces - Google Patents

Description

Nov. 28, 1950 L. E. SEELEY 2,531,864

SECTIONALLY REMOVABLE AND REPLACEABLE FIREBOX FOR FURNACES 5 Sheets-Sh eet 1 Filed Sept. 11, 1945 4 MI W .5

1'1720672507 l ffi iif Nov. 28, 1950 1 E. SEELEY 2,531,364

SECTIONALLY REMOVABLE AND REPLACEABLE FIREBOX FOR FURNACES Filed Sept. 11, 1945 5 Sheets-Sheet 2 Nov. 28, .1950 E. SEELEY 2,531,864 SECTIONALLY REMOVABLE AND REPLACEABLE FIREBOX FOR FURNACES Filed Sept. 11, 1945 3 Sheets-Sheet 3 g3 eg @mr QMEIZ 62 55 y qia 64mm. 0 5:4.

Patented Nov. 28, 1950 UNITED STATES PATENT OFFICE SECTIGN ALEY REMOVABLE AND REPLACE- ABLE FIREBOX FOR FURNACES Application September 11, 1945,. Serial No. 615,591

r Claim.

This invention pertains to heat. exchange apparatus and relates more particularly to, an. improved firebox or combustion chamber designed to. be. arranged within an air or water cooled housing. Such a heat exchange apparatus may, for instance, be an oil-fired house-heating iurnace, for instance, a steam or hot water. boiler, and for convenience in description, but without limitation as to its utility, the invention. will herein be referred to such an embodiment.

The most common type of firebox orcombustion chamber employed in, furnaces of this type is constructed or refractory material, usually 1-efractory bricks bonded by high temperature clays or other substances. These refractory bricks are capable of withstanding very high temperatures for a long time without substantial deterioration. However, such a refractory lining is heavy, requiring strong support; it is of substantial thickness, thus reducing the capacity of the combustion chamber; and, in course of time it becomes necessary to patch, or rebuild such a refractory lining which is a troublesome and expensive operation.

It has heretofore been proposed to substitute a metal combustion chamber for the common refractory lining, in particular in oil-burning furnaces. Such a metal. combustion chamber may be made of, thin material, for example, stainless sheet steel which resists corrosion at temperatures. Such a combustion chamber has the great advantage, over the refractory type, in that it may be made to exact shape and size at the factor or of interchangeable parts which may be assembled in the field with the remaining of the furnace installation, without reliance upon the uncertainty of building operations, that is to say, the construction of a brick. chamber. It is common knowledge that the shape and size of the firebox must be appropriate to the nature and capacity of the fuel-burning device, and that if of, proper shape and size, a metal. firebox Will insure good burner operation and econom in fuel. By adopting a metal firebox, the maker of the furnace or of, the oil burner is no longer dependent upon the skill or care of the person who sets up the furnace in the field to insure that the firebox will be of the proper shape andv dimensions. However, as heretofore constructed, such metal fireboxes have, not been satisfactory. The walls of such a firebox become very hot during burner operation, a red heatbeijng quite com mon. m; fact-tor the. proper; burning of fuel, especially oil, it is requisite that the Walls of the firebox reach a temperature ore-ye,

when the metal. box is constructed as has been customary, it isfound that the walls "of the box: may become sufiiciently plastic, when thus highly heated, to be deformed merely byreasonoi the; weight of the material. Furthermore, the location of said surfaces bears a certain substantially uniform relation to, the heatabsorbing backing, and to the intensity of the heat sup plied. by the flame., the various parts of the firebox may be so differently heatedas to set strains which distortand mayeventuall'y destroy. the utility of the firebox. Espec-ial difficulty Hasbeen experienced when the several parts of the structure are welded together. 7 r

The invention has for its principal object the provision of a metal-walled firebox or combustion chamber having all of the advantages. inherent in the employment of metal walls, for instance rapid heat transmission, light weight, and small volume, but which at the same time is substan tially free from the defects common to priormietal walled fireboxes. A further object is to provide an improved firebox having metallic side walls and if desired a metal :fio'or, and whose parts are so designed and arranged as to permit them to be assembled very readily, either by the maker of the furnace, by the assembly man, in the field where the furnace is being erected, or by the re pair man, the introduction and assembly of the parts being so simple and easily performed that it may be done, even by the unskilled, in very short time and Without the necessity for special.

tools. A further object is to provide an improved firebox so designed that lack of uniformity of heat distribution has no damaging efiect upon the shape and structure of the firebox as a whole, the various parts of the firebox being free for. indi vidual expansion both lengthwise and sidewise without causing buckling or distortion of adjacent parts. A further object of the invention is to provide a metal firebox of such construction that by the employment of standard size part5, fireboxes for furnaces of different sizes may reads ily be constructed merely by the selection of the proper sized parts and the proper number of such parts; Other and further objects and ad vantages of the invention will be pointed out in the following more detailed description and'b'y reference to the accompanying drawings wherein; Fig. 1 is a front elevation of the lowerpartoi the front section of a boiler embodying themesent invention; I r r 7 Fig. 2 is; an elevation of the-rear seamsof the boiler;-

Fig. 3 is a horizontal section through the boiler, substantially on the line 3-3 of Fig. 2;

Fig, 4 is a perspective view of one of the. constituent plates of the combustion chamber designed to be employed at the door opening;

Fig. 5 is a perspective view of a ptate useful at the side or rear of the firebox;

Fig. 6 is a fragmentary perspective view of a bottom plate;

Fig. '7 is a fragmentary perspective view of a hanger for supporting the plates constituting the combustion chamber; and

Fig. 3 is a perspective view illustrating a modified form of hanger.

The metal firebox of the present invention has walls consisting of a plurality of independent parts of simple shape, which are not liable to warp, and which are individually free to expand laterally and longitudinally without affecting contiguous parts. Thus there is no possibility of placing the structure as a whole under strain, and warping and breaking cannot readily occur. It is to be understood that the metal firebox of the present invention is for use only in cases where there is an appropriate heat-absorbing backing, for instance a water backing, behind the firebox wall. Thus it is proposed to hang suitable metal sheets or plates on supports carried by or incorporated in the heat-absorbing structure of the furnace and so arranged as to insure the desired spacing between said. sheets or plates and the heat-absorbing surface. The sheets or plates are hung side by side with open joints sufficient to allow for expansion of the parts. The space between these sheets or plates and the absorbing surface may be determined by suitable designing of the supports for the plates or by the employment of other simple spacing means so devised as to insure a spacing of the desired amount and uniformity. The part or parts which form the floor of the firebox may, if desired, rest directly upon a heat-absorbing surface, such as a water backing or more simply upon a masonry support. The lower edges of the side wall plates or sheets are spaced from the fioor or bottom wall of the firebox so as to permit free expansion in this direction. Fireboxes of substantially any desired size may be made merely by employing an appropriate number of the freely suspended sheets or plates which may, if desired, be provided in a range of standard sizes to facilitate the construction of fireboxes of any reasonable dimensions. The space between the metal sheets or plates forming the wall of the firebox and the heat-absorbing backing is so dimensioned as to provide the desired heat transmission without danger of overheating the metal walls of the firebox. 1

One advantage of the metal firebox is the saving in space which is very important, especially in small heaters and in domestic warm air furnaces especially. In accordance with the present invention the plates forming the sheet metal walls of the firebox are freely suspended from their upper edges. Thus they may be made of thin material and the thickness of these sheets, together with the width of the space between them 'and the heat-absorbing surface, may be less than that of an equivalent structure of refractory brick. Thus more space is available for the firebox itself.

over, since the metal firebox walls radiate heat very rapidly to the heat-absorbing surfaces behind, a very high thermal efiiciency may be obtained.

In the accompanying drawings, and in the following description, the improved firebox of the present invention is shown as embodied in a heater of the sectional water-leg type, for instance a domestic hot water or steam boiler, but it is to be understood that this novel firebox is equally applicable and of utility in heaters of other types, the only essential requisite in embodying it in one or another type of heater being that the supporting means for the firebox parts be suitably mounted on and fixed to the other and conventional parts of the heater structure.

Referring to the drawings, the numeral I designates the front section of a water-leg boiler having the water- legs 2 and 3 disposed at 0pposite sides of the firebox. The numeral I (Fig. 2) designates the rear section, having the waterleg portions 4 and 5 respectively, and the numerals 6 and 1 indicate the water-legs of an intermediate section, it being understood that as many intermediate sections as desired may be interposed between the front and rear sections l and l The legs 2 and 3 of the front section are so shaped and spaced as to provide the fire door.

opening 8 and, as illustrated in Fig. 3, the legs 4 and 5 of the rear section are shaped so as collectively to extend nearly across at the back, but are also spaced a short distance apart at the point 9. The legs of the front and rear sections are also spaced from the intermediate section as indicated at Ill and only contact the intermediate section by means of spacer lugs II, the several section; being connected together to form the assembled boiler structure by suitable bolts, push nipples and the like (not shown) in accordance with the usual practice.

In accordance with the present invention, a plurality of hangers or brackets I2 (castings or sheet metal sections) are provided (Fig. 7) one desirable form of bracket is substantially L- shape in vertical section and comprises the vertical attaching flange or web l3, the horizontal flange l4 and the upwardly directed supporting flange or lip l5, the parts thus defining a substantially horizontal channe1 I B, the width of the flange I4 determining the spacin of the lip 15 from the flange [3. The vertical flange I3 of the bracket is provided with openings IT for the reception of attaching elements. bracket having the channel is desirable, hangers of other types, for example a hanger or bracket l2 which has merely the equivalent of the lip I5, may bev employed. The walls of the firebox are defined by independent plates of a suitable Since metal fireboxes heat up more quickly than a refractory lining, the optimum conditions for combustion will be arrived at sooner. and

this tends to a better economy of fuel.. Morerefractory, that is to say heat-resistant material. These plates are quite thin, as compared with the usual fire brick used for lining the firebox of such a heater,. for instance these plates may be of metal of the order of 1% of an inch thick. The thickness will depend to some extent upon the material employed, although it is desirable to make them as thin as is consistent with durability in order to make their Weight small and to avoid undue Waste of space. These plates are made of proper size and contour for the intended purpose and if desired may be made in a range of standard sizes. Merely by way of example the vertical wall plates may be of the order of twelve inches in vertical length. As here j illustrated the end wall plates 18 are of uniform While this width, for example, of the order of five inches wide, while the rear wall plates 18 (Fig. 3) are wider than the end wall plates, for example, of the order of seven inches wide. Each of the vertical wall plates 88 and l8 is furnished with a horizontal flange l9 at its upper end, the flange I9 having a downwardly directed lip or hook member 28 designed to seat in the channel It of one of the supporting brackets. While the integral parts [9, 28 constitute simple and reliable hook elements for engagement with the brackets IE, it is obvious that equivalent suspendin means may be employed.

The front wall plates 22 are, in general, similar to the end and rear wall plates, having similar stop flanges l9 and downwardly directed hook elements 28. These front plates may for example be of an extreme width like that of the'rear wall plates, but are cut away at 23 so as to provide the desired fire door opening. the vertical wall plates is furnished with a horizontal flange 2| at its lower edge, these flanges helping to stiffen the plates and also constituting spaces to hold the lower portions of the plates in proper spaced relation to the heat absorbing elements of the boiler.

Floor plates 24 (Fig. 6) are also provided, these plates preferably being of material like that used in making the side wall plates and each of the plates 24 preferably having a downwardly directed supportin and spacing flange 25 and 26 respectively at its opposite edges.

In assembling the firebox within the boiler, the brackets or hangers [2 are first fixed in proper position within the structure of the boiler,

flanges 25 and 2B directed downwardly. These flanges may rest upon the top of a suitable waterleg beneath the firebox, if such be provided or if not, then upon a body 28 of masonry, for example fire brick.

The end Wall plates H! are then introduced through the fire door opening, one after the other, and lifted up until their hook elements 29 may be hooked over the lips l5 of the corresponding supporting brackets, the plates then being dropped down until their hooks 20 seat in the channels l8 of the brackets. The rear wall plates I8 are similarly introduced and likewise the front Wall plates 22.

It may be noted that the several wall plates are of such widths that when they are properly disposed within the firebox so as collectively to constitute the wall of the latter, open joints 2!], for example, of the order of inch wide, are left between them. Likewise the vertical height of the side wall plates is such that their lower edges are spaced (for example, inch) as shown at 30 (Figs. 1 and 2) from the upper surfaces of the front plates 24.

Preferably, each of As thus arranged, each individual plate is free to contract and expand in all directions without in any way affecting the other plates so that cramping and buckling of the walls of the firebox is avoided. If at any time it be desired to replace one of the plates it is merely necessary to reach in through the fire door opening, grasp a particular plate and lift it so as to disengage its lip 28 from the channel It and then lower the plate and withdraw it through the fire door opening. A new plate may be introduced as easily to take its place.

By properly dimensioning the brackets l2 and the flanges 25 of the plates, the latter may be spaced at any desired distance from the surfaces of the heat-absorbing elements of the boiler, thus insuring a predetermined spacing such as desired.

While one desirable embodiment of the invention is herein illustrated and described by way of example, it is to be understood that the invention is broadly inclusive of any and all modifications falling within the scope of the appended claim. While as above suggested metal plates are desirable, especially in view of their high heat conductivity, it is contemplated that plates of other materials may similarly be supported to form the walls of the firebox if for any special reason it should be desired to do so.

I claim:

In combination in a heater having conventional heat-absorbing members arranged to define a combustion chamber, brackets secured to the heat-absorbing members within said chamber having upturned hook-shaped ledges, a. plurality of thin refractory plates, downturned hookshaped flanges at the upper edges, said plates being arranged to hang freel'y from said ledges by interengagement of the .jdownturned hookshaped edges of the plates therewith and spaced around the interior of thechamber collectively to constitute a fire wall, said plates having open joints between their parallel edges, said walls being spaced inwardly of the-heat-absorbing members, and rearwardly extending flanges at the bottom edges of the plates'adapted by engagement with the heat-absorbing members to inhibit lateral rearward movement of said plates.

LAUREN E. SEELEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 63,539 Low Apr. 2, 1867 147,881 Truesdale Feb. 24, 1874 270,127 Robb Jan. 2, 1883 425,943 Hogan Apr. 15, 1890 835,686 Kulla Nov. 13, 1906 FOREIGN PATENTS Number Country Date 18,871 Great Britain Aug. 23, 1906 526,534 Germany June 6, 1931

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