US610037A - Hot-air furnace - Google Patents

Description

No. 6l0,037. Patented Aug. 30, I898.

.l. EVANS. HOT AIR FURNACE.

(Application filed JLI'L 17, 1898 w 3 Sheets-Sheet l.

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No. 610,037. Paieenzsmiz Aug. 30, I898.

J. EVANS.

HOT Km FURNACE (Application' and 3m, 17, 189m el.) 3 Sheets-$heefl 2.

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N0. 610,037. Patented Aug. 30, I898. J. EVANS.

HOT AIR FURNACE.

( Application filed Jan. 17, 1898.)

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JOHN EVANS, OF PHILADELPHIA, PENNSYLVANIA.

HOT-AIR FURNACE.

SPECIFICATION forming part of Letters Patent No. 610,037, dated August 30, 1898. Ap licatien filed January 17, 1898. fierial No. 666,873. (No modelo To aZZ whom it may concern:

Be it known that I, J OHN EVANS, a citizen of the United States, residing at the 'city of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Hot Air Furnaces, of which the following is a specification.

My invention has relation to a hot-air furnace, and in such connection it relates particularly to the construction and arrangement of the parts comprising such a furnace.

The principal objects of my inventionare, first, to reduce the cost of such a furnace by simplifying the construction and arrange ment of the parts thereof as well as by re ducing the number of such parts; second,'to

increase the efficiency of the furnace by utilizing in an economical manner all the heat products and by'increasing the amount of heat arising therefrom by causing a more complete combustion of the gases and other products; third, to prevent during the open ation of the'furnace the escape of gas, smoke, or other products of combustion into the hotair-supply conduits or tubes; fourth, to permit of the entrance of the cold air at a point which will prevent the entrance therewith of dust, and, fifth, to utilize the products of combustion so that the air in the ash-pit may be warmed and to present this warmed air below and above the grate of the furnace.

My invention, stated in general terms, consists of a hot-airfurnace constructed and ar ranged in a manner substantially as hereinafter described and claimed.

The nature and scope of my invention will be more fully understood from the following description, taken in connection with the accompanying drawings, forming part hereof, and in which 1 Figure l is a vertical sectional view of a hot-air furnace embodying main features ofmy invention, said section being taken on the line 1 1 of Fig. 3. Fig. Zis a transverse sectional view on theili'ne 2 2 of Fig.'1. Fig. 3

'is a similar sectional view on the line 3 3 of Fig. 1." Fig. lis a vertical sectional view of the lower portion ofthe furnace, said section being taken on the line t 4; of Fig.5; and Fig. 5 is a transverse sectional view on the line 5 5 of Fig. 4.

any suitable manner.

Referring to thedrawin gs, A represents the exterior casing of the furnace supported upon I the casing A, and supported byjthe bed-plate A, substantially as hereinafter described, is

arranged a series of box-shaped castings a, one side a of each of which is curved and rests adjacent to the fire-pot B and combustion-chamber D of the furnace, whereas the opposite side is open and provided with flanges or wings a which when the castings are assembled together overlap, as shown in Fig. 3, and form spaces 1) between the boxes,

which spaces, as hereinafter described, form flues for the passage of the products of coin bustion. The lower ends of these castings a converge or taper to a flat portion a which rest in an annular groove a formed in the bed-plate A, as shown in Fig. 1, and the flat portions of the castings form when the parts are assembled a circular wall surround ing the base of the ash-pit E, as shown in Figs. land 5. The inner side of the fire-pot B is provided with a ledge cl, serving as a support for the shelld of the combustion-chamber'D, and the outer side of these castings a is also provided-with a ledge 6, serving as a support for the cylindrical shell 6, which serves to close the'open sides of the castings, as shown in -Figs..1 and 3, and to form therewith hot-air conduits a The casting f of the ash-pit E is supported at its front end by an external casing A and near its rear end by a girder f, resting on the bed-plate A or in The casing f' of the ash-pit rests at its upper edge against the inner surface of the castings a at the point where said castings begin to taper, and this upper edge is provided with a ledge g, serving as a support for the ring or shell B of the fire-pot B and also for the fire-brick g, forming the lining of the firo=pot B, as shown in Fig. 1. These bricks 9 rest directly against the shell B of the fire-pot B, but are provided with grooves or conduits g having an upper outlet 9 into the base of the combustion-chamber D and lower inletsg com-. municating with the interior. of the ash-pit below the grate F, as shown in Figs. 1 and 3. The purpose of this arrangement will be described hereinafter. The shell d' of the combustion-chamber D is provided with a ledge m, adapted to support a funnel-shaped piece m, which serves to guide the products of combustion directly upward.

Above the castings a and preferably secured thereto by bolts is located a cap G, shaped in cross-section as shown in Fig. 2, and it consists of a number of box-shaped arms or projections h, the interior of which communicate directly with a central chamber h, located directly above and surrounding the funnel-shaped piece mof the combustion-chamber D. The interior of the arms It also communicate through openings Z) wit-h the flues b. The arms h are separated from each other by similarly-shaped spaces 71}, which are directly in communication with the top of theair-chambers a, formed by the castings a, and also with the interior of the air drum or dome A as shown in Fig. 1. The lower ends of the flues b are open, as at 5 and communicate directly with the space f below the ash-pit E, whereas the lower ends of the air-chambers a are open, as at a, and communicate with the space (t formed between the casing A and the exterior face of the castings. The bed-plate A is provided with a number of openings a as shown in Figs. 1 and 5, to permit communication between the space a and a space (1 below the bed-plate A.

The off-take pipe II for the smoke and other products of combustion is continued vertically down the side of the furnace and is provided with two branch pipes H and H of which the pipe I-I leads directly to the combustion-chamber D, whereas the other pipe I-l leads to the space f below the ashpit E,

' as illustrated in Fig. 4. The off-take pipe II extends within an extension A of the casing A. This extension A serves as a jacket for the pipe II and also as a duct for the entrance of cold air, which air enters at the top of the jacket near the top of the furnace and passes down the pipe H to an opening A, through which it passes into the space a below the bed-plate A.

An important feature of the present invention resides in the manner of securing the castings a together to form the air-chambers a and flues b, so that the products of combustion in the lines or other parts of the furnace cannot enter the air-chambers. To accomplish this, the castings a, as hereinbefore described, are provided at their sides with the flanges or Wings a and at their tops with the flanges a and a These flanges overlap, and between the overlapped flanges a sheet or layer 6612, of asbestos paper or similar fireproof material, is placed prior to the bolting of the flanges together. With this construction expansion and contraction of the castings due to changes in temperature within the furnace may take place without disturbing the tightness of the joint thus formed, the wings or flanges sliding over each other without separating.

In securing the cap G to the castings a a similar construction is employed. In this instance the flange G' of the cap overlaps the flange d or a of the castings, and between these flanges G and a or a a layer of asbestos paper 00 is inserted before the flanges are bolted or otherwise secured together.

In operation fire is started in the tire-pot B, and the smoke and products of combustion enter the combustion-chamber D. From this chamber a portion of the products pass through the pipe H to the off-take pipe H, near the upper end of the jacket A The remainder of the products of combustion ascend to the chamber h of the cap G and are deflected through the interior of the arms h to the flues b, from which it passes into the space f below the ash-pit E, heating said ash-pit, and then passing out through the branch pipe 11 into the off-take pipe II. The air which is admitted to the ash-pit E through its door E is heated before it enters below the grate F by the passage of products of combustion around the ash-pit, and a portion of this heated air in the ash-pit passes through the openings or inlets g and the grooves g and the outlets g into the combustion-chamber D, serving thereby to materially assist in the combustion of gases and other products in said chamber D. The passage of the products of combustion through the flues 1) serves to highly heat the castings a, which from their close proximity to the fire-pot and combustion-chamber are also highly heated by the combustion of products in said fire-pot and combustion-chamber. The cold air enters at the top of the jacket A and passes down the heated off-take pipe H into the space (1 below the bed-plate A, and from thence through the openings a into the space a between the castings and easing A, and thence into the air-boxes a from which it is delivered to the spaces h of the cap G and to the dome or air-drum A and escapes into the pipes A leading to the registers. By taking the cold air in at the topof the jacket A it will be readily understood that the air will be cleaner than if taken in at the base vof the furnace, as has been heretofore the practice, since all furnaces at their base are clogged with dust and ashes, the lighter particles of which will flow in with the inrushing air. The cap G being situated directly above the combustion-chamber is highly heated by those products of combustion which are conducted through the flues b, and hence the air after it is delivered from the air-boxes a to the spaces 7L2 of thecap G is still further heated by said cap G before it escapes from the drum A By resting the flattened ends a of the castings a in the groove a of the bed-plate A a tight joint is formed without the use, as heretofore, of cement, since a deposit of grit and IIO soot from the products of combustion as they pass through the space below the ash-pit will enter the groove and serve to seal the joint therein.

Having thus described the nature and objects of my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In a hot-air furnace, in combination with a fire-pot and a combustion-chamber, a series of castings arranged around the fire-pot and combustion-chamber, said castings being provided with flanges adapted to overlap to form alternate flues and air-boxes, the lower end of said castings tapering to a substantially flat portion to form below the fire-pot a circular wall, and a bed-plate arranged below the fire-pot and provided with an annular groove adapted to receive and support the flat portionsof the castings, substantially as and for the purposes described.

2. In a hot air furnace, in combination with a fire-pot and a combustion-chamber, a series of castings arranged around said fire-pot and combustion-chamber, said castings being provided with flanges adapted to overlap toform alternate flues and air-boxes, and a cap located above the combustion-chamber and upon the castings, said caphaving its interior in communication with the combustionchamber and the flues and its exterior in com-.

munication withv the air-boxes, substantially as and for the purposes described.

3. In ahot-air furnace, in combination with the fire-pot, combustion-chamber and exterior casing, of a series of castings arranged adjacent to the fire pot and combustionchamber and within the casing, said castings being provided with flanges adapted to overlap to form alternate flues and air-boxes, a cap located above the combustion-chamber and having its interior in communication with said chamber and with said flues and having its exterior in communication with the airboxes, and an air-drum supported by said casing and inclosing said cap, substantially as and for the purposes described.

ash-pit, substantially as and for the purposes described.

5. A hot-air furnace, comprising an exterior casing, a hollow bed-plate supporting the casing, an air-drum supported upon the easing, an ash-pit supported within the casing above the bed-plate, a fire-pot and combustion-chamber arranged within the casing and above the ash-pit, a series of castings supported by the bed-plate and surrounding the ash-pit, fire-pot and combustion-chamber, said castings having flanges adapted to overlap to form alternate flues and air-boxes, a cap surmounting the combustion-chamber and supported by the castings, the interior of said cap communicating with the combustion-chamber'and the flues and the exterior of the cap communicating with the drum and the air boxes, said flues opening into the space below the ash-pit and the air-boxes communicating with the interior of the hollow bedplate, an offtake-pipe, branch pipesleading to the combustion-chamber and to the space below the, ashpit, and a jacket surrounding the offtake-pipe and open at its upper end for the reception of the cold air and communicating directly with the interior of the bed-plate, substantially as and for the purposes described.

In testimony whereof I have hereunto set my signature in the presence of two subscribing witnesses.

JOHN EVANS.

WVitnesses:

J WALTER DoUeLAss, THOMAS M. SMITH.

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