US1952023A - Furnace - Google Patents

Description

March 20, 1934. E. R. REEVES FURNACE Filed Feb. 20, 1933 I N VEN TOR .Edward- A? Pazves.

A TTORNEYSZ Patented Mar. 20, 1934 UETE stares FURNACE Application February 20 1 Claim.

My invention relates to furnaces. It has to do, more particularly, with the provision of a novel type of liner for the fire-box of a furnace. It is particularly applicable to those types of furnaces which are adapted to burn coal, coke, wood or other such substance, although there are certain features of my invention which are not necessarily limited to such types of furnaces.

In the prior art, there have been many attempts to devise a suitable type of liner for fireboxes of furnaces of the type indicated. These prior art'devices whichhave been devised have all been possessedv of certain undesirable features. The prior art liners which have been devised have not been suficiently rugged to withstand the great heat to which they are subjected. They have been of such a type that when'they become hot they bulge inwardly towards the center of the fire-box and in some cases, they bulge to such an extent that they work loose from their supporting structures and fall out of place. Likewise, in prior art structures, there has been no adequate means for taking care of the expansion and contraction of the liners. Since no adequate means of this type has been provided, the expansion and contraction, caused by changes of temperature, in the furnace, has caused splitting and cracking of the liners.

One of the objects of my invention is to provide a furnace of the type indicated having firebox liners therein, which are of an extremely rugged construction and which will not be distorted by the heat to which they are subjected.

Another object of my invention is to provide a fire-box liner of the type indicated which is provided with means for compensating for the expansion and contraction of the entire liner, in order to prevent splitting or cracking of the liners'when they are mounted in a furnace, such means being also adapted to preclude the setting up of internal strains in the liner itself, which are caused by unequal expansion and contraction of different portions of the liner, due to the different intensities of heat to which various portions of the liner are subjected.

Another object of my invention is to provide a fire-box liner of the type indicated which is provided with means for offsettingthe tendency of the liner to bulge inwardly towards the center of the fire-box when the liner is incorporated in a furnace and subjected to a great amount of heat.

In its preferred form, my invention contemplates the provision of a furnace which is provided with grates suitably supported on members 1933, Serial No. 657,529

disposed around the walls of the furnace. Each side and the rear of these grates are spaced from the walls of the furnace. At each side and at the rear of these grates and above the space between the grates and the walls of the furnaces, I mount a plurality of fire-box liners which extend entirely around the fire-box.

These liners are extremely rugged in structure so that they will not be distorted by the heat in the fire-box. Furthermore, they are also provided with means for offsetting the tendency of the liners to bulge inwardly towards the center of the fire-box. Means is alsoprovided in the liners to take care of the expansion and contraction of these liners and to preclude the setting up of internal strains therein, in order to prevent splitting and cracking thereof. I have also provided a rib adjacent the lower edge of each liner, so that when the liners are placed in the furnace, an inwardly projecting shelf will be formed on the wall produced by the liners. A layer of ashes or other refractory material may be built up on this shelf and against the inner surfaces of the liners so that they will be protected to a considerable extent from the intenseheat of the fuel bed. This shelf member also prevents intense combustion directly adjacent the liners, as will be later explained. The liners are also provided with openings adjacent the upper end thereof so that pre-heated air may flow upwardly through the space between the edges of the grates and the walls of the furnace, then through the space between the liners and the walls of the furnace, and then inwardly through such openings and over the fuel bed.

The preferred embodiment of my invention is shown in the accompanying drawing wherein similar characters of reference designate corresponding parts and wherein:

Figure 1 is a transverse section of a furnace of a suitable type which is provided with my novel type of fire-box liners mounted therein.

Figure 2 is a perspective view of a fire-box liner made in accordance with my invention.

With reference to the drawing, and particularly to Figure l, I have shown a furnace l which is of a type adapted to burn coal, coke, wood or other such fuels. The furnace shown comprises side plates 2 and 3 which are preferably of cast iron. It will be apparent that the rear end of the furnace is closed by similar cast plate while the front end of the furnace is provided with a suitable door construction. The lower ends of side plates 2 and 3 are provided with flanges 2' and 3' respectively which are disposed at right angles to the plates 2 and 3 and rest on a suitable base structure 4.

A plurality of supporting brackets 5 are mounted at each side of the furnace on plates 2 and 3 adjacent the lower ends thereof and are secured thereto in any suitable manner. These supporting brackets 5 extend inwardly from the walls of the furnace a considerable distance. It will be understood that any number of these supporting brackets may be used. The sup= porting brackets 5 are adapted to support a pair of grate supporting members 6, one of which is mounted at each side of the furnace on such members. 7

It will be apparent from the drawing that the supporting members 6 are arranged at the outer ends of supporting brackets 5 and may be suitably secured thereto. A space '7 is produced between the grate supporting members 6 and the inner surfaces of the side walls of the furnace and since the supporting brackets 5 are disposed in spaced relation, 'air may fiow up through the space '7 for a purpose which will be later explained. I

The supporting members 6 are adapted to support a grate structure 8 which has its outer edges resting on the upper edges of the supporting members 6. It will be understood that this grate structure 8 may be of any suitable type and is provided with means for discharging the ashes therefrom. A'n ash pit 9 is formed below the grates 8 and a fire box 10 is formed thereabove. v

As shown in the drawing, a plurality of firebox liners '11 are adapted to be arranged around the edges of the grates 8 in order to form a liner construction for the walls of the fire-box 10.

Each of these liners 11 is preferably of the type shown in Figure 2. The liner 11 is preferably of cast iron and comprises a body portion 12 having vertically extending fiange's 13 formed 'at each end thereof and projecting outwardly from the rear surface thereof. These flanges 13 are provided with recessed portions 1'4 on their rear edges for a purpose which will be later ap parent. As shown more clearly in Figure 1, the flanges 13 project rearwardly from the body por tion 12 of the liner a comparatively great dis tance at their lower ends but this distance grad ually decreases towards the upper end of the liner. The lower ends of the flanges 13 project downwardly from the lower edge of the body portion 15-3 of the liner to form downwardly projecting extensions or lug members 15.

It will be understood that the flange members 13 will serve to prevent buckling of the liner member 11. Oh the inner surface of the body portion 12 of the liner, and adjacent the lower edge thereof, a rib or shelf member 16 is formed. This rib or shelf member 16 extends for the entire length of the liner and extends outwardly a considerable distance therefrom. The lower edge of the rib 16 is inclined as at 17 and the inner edge of the downwardly projecting members 15 are also inclined as at 18. The longitudinally extending rib 16 will also serveto prevent buckling or bulging of the liner. By providing the vertically extending flanges 13 and the longitudinally extending rib 16, a very rugged liner is produced which will withstand a very great amount of heat without bulging or becoming distorted in any way.

I have also provided additional means for preventing bulging of the liner 11. It is wen known that when the inner surface of the liners of furnaces become hot, due to the heat in the fire-box, the entire liner tends tobulge inwardly towards the hot side of the liner and inwardly towards the center of the fire-box. In order to offset this tendency and to prevent inward bulging of the liner 11, I provide a dc" pressed portion or concavity 19 formed in the body portion 12 of the liner. As shown in Figure 1, by providing the depressed portion 19 in the liner, a portion of the body portion 12 is caused to project outwardly from the rear surface thereof as at 19. Because of this depressed portion 19 the tendency of the liner will be to bulge outwardlyand will therefore offset the tendency of the liner to bulge inwardly. Furthermore, by having a portion of the body portion of the liner extending outwardly as at 19', the liner is stiffened against inward bulging.

I have also provided means for taking care of the expansion and contraction of the entire liner which will occur when it is mounted in the furnace and for precluding the setting up of internal strains therein, which would otherwise be caused by unequal expansion and contraction of different portions of the liner, due to the fact that various portions of the liner are subjected to diiferent intensities of heat.

This means comprises a pair of slots 20 which are formed in the concave portion 19 of the liner and which extend entirely through the liner. These slots are disposed diagonally of the concave portion 19 of the liner and intersect at a point 21 which is preferably at the center of the concave portion 19. When the liner becomes hot it tends to expand and since the various liners are disposed in close relation with each other in the furnace this would cause cracking or splitting of the liners if means were not provided for taking care of this expansion. Furthermore, since different portions of the liner are subjected to different amounts of heat, the expansion and contraction of various portions of the liner will be unequal.

However, with my liner when it becomes hot the metal may expand inwardly from any or all directions and will make the slots 20 narrower. The expansion in any direction may be faster or slower than the expansion and contraction in any of the other directions. When the liner again becomes cool it will contract and the slots will become wider. Thus, the slots 20 permit expansion and contraction of the liner in any or all directions without affecting the liners adjacent thereto in the furnace, and without setting up any internal strains in the liner itself. This expansion and contraction may also be unequal in various directions.

The liner 11 is also provided with a series of apertures 22 arranged adjacent the upper end thereof. These openings are provided so that air may pass therethrough and into the upper portions 'of the fire-box.

As shown in Figure 1 of the drawing, a series of these liners are mounted in the furnace around the edges of the grates 8. When these liners are mounted in the furnace the downwardly extending portions 15 are inserted in the space between the grate supporting members 6 and the walls of the furnace. Since the portions 15 extend downwardly between the grate supporting members 6 and the walls of the furnace a considerable distance, they serve to securely hold the liners in position in the furnace. The lower edge 1'7 of the rib 16 on the body portion of the liner will rest on the upper edge of the grate supports 6. The flanges 13 will contact with the walls of the furnace and because of the shape of these flanges the body portion of the liners will be disposed in inclined relation so that a wide space will be formed between the said body portion and the walls of the furnace at the lower end of the liner while the upper end of the body portion will contact with the walls of the furnace. Since the flanges 13 are provided with the recessed portions 14 on their rear edges they will contact with the walls of the furnace only at their upper and lower ends, thus ensuring proper fitting of the liners against the walls of the furnace. Furthermore, the upper surface of the shelf or rib member 16 will be disposed in inclined relation, with the outer edge thereof disposed at a higher point than the inner portion thereof.

When the liners are incorporated in a furnace as shown in Figure 1, all the ribs or shelf members 16 of the liners cooperate in producing a shelf member 16 extending entirely around the firebox and slightly spaced above the grates 8. This shelf is provided in order to permit the building up of a layer of ashes on the shelf and against the inner surface of the fire-box liner formed by the liners 11. The building up of this layer of ashes is facilitated by the fact that the shelf member 16 is inclined and also by the fact that the body portions of the liners are disposed in inclined relation. This layer of ashes will serve to partially protect the liners from the intense heat of the fuel bed. A layer of any other refractory materials might be built up on the shelf member 16 to protect the liners, as explained above.

The shelf 16' will also serve an additional purpose, as will be clearly apparent from the drawing. Air will flow upwardly from the ash pit through the space between the edges of the grates and the supporting members 6. If the shelf member 16 were not provided this air would fiow upwardly along the inner surfaces of the liners, and would cause intense combustion to take place directly adjacent the inner surfaces of the liners, subjecting them to intense heat. However, with my liners, the upwardly flowing air will strike the shelf member 16' and will be deflected inwardly towards the center of the firebox, thereby preventing the intense combustion directly adjacent the liners.

Preheated air may pass from the ash pit 9 up through the space 7 between the grate supporting members 6 and the walls of the furnace, up-

wardly through the space between the liners 11 and the walls of the furnace, and finally out through the apertures 22 into the upper portions of the fire-box.

It will be understood from the above description that I have provided a liner member having many desirable characteristics. This liner is of such a type that it is extremely rugged in structure and will withstand a great amount of heat. Furthermore, I have provided means which olfsets the tendency of the liner to bulge inwardly towards the center of the fire-box, thus eliminating any possibility of the liner working out of place and falling inwardly into the fire-box. Likewise, I have provided means for taking care of the expansion and contraction of the liners when they are in a furnace and for precluding the setting up of internal strains therein so that splitting or cracking of the liners will be precluded. Also, I have provided means comprising a shelf member on the inner surface of the liners which makes it possible to build up a layer of ashes or other refractory material against the liners in order to protect the liners from the intense heat of the fire bed. Furthermore, this shelf member prevents intense combustion directly adjacent the inner surfaces of the liners, and thereby, decreases the amount of heat to which the liners are subjected.

Having thus described my invention, what I claim is:

In a furnace construction comprising a firebox, grates forming the bottom of said fire-box, said grates being spaced from the walls of said furnace, a liner member for the fire-box, said liner member comprising a body portion having a depressed portion on the inner surface thereof. a shelf member projecting from the inner surface of said liner member adjacent the lower edge thereof, slots formed in said liner member to compensate for expansion and contraction of said liner member, said liner member being provided with rearwardly projecting flange members adapted to maintain the greater portion of said body portion in spaced relation to the walls of said furnace, said flanges being provided with downwardly extending portions adapted to fit into the space between the grates of the furnace and the walls of the furnace, and said liner member being provided with a plurality of openings extending therethrough at the upper end thereof for establishing communication between the firebox and the space behind said liners.

EDWARD R. REEVES.

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