US2689605A - Furnace structure - Google Patents

Description

Sept. 21, 1954 F. o. HESS FURNACE STRUCTURE Filed Nov. 29 1950 FIG.

1N VEN TOR.

FIG.|

llal twnl BY FREDER/ 0.17555 ATTORNEY.

fuel conduit.

Patented Sept. 21, 1954 FURNACE STRUCTURE Frederic 0. Hess,'Philadelphia, Pa., assignor to Selas Corporation of America, Philadelphia, Pa., a corporation of Pennsylvania Application November 29, 1950, Serial No. 198,131

8 Claims.

The present invention relates to furnaces using fluid as a fuel, and more particularly to a simplifled means of supplying fuel and air to the burners of such a furnace with a minimum of piping.

In a furnace using gas or oil or other fluid as a fuel it is necessary to have a main supply pipe for the fuel and for the combustion supporting air. Pipes are needed to connect each burner or groups of burners with one or more manifolds and to connect these with the supply main. The piping arrangement, particularly in a furnace having a relatively large number of burners, becomes complicated. Furthermore, the cost of installing the supply pipes, as well as their maintenance is expensive;

It is an object of the present invention to overcome these objections by providing novel means which use a minimum of piping to supply fuel and air to a burner of a furnace. It is a further object of the invention to use the furnace itself and the reinforcing members forming part of the furnace construction as a portion of the In carrying out the present invention various structural reinforcing members of a furnace are made in the form of ducts, or portions of ducts, through which the fuel and air, or a mixture of the two may be passed. These ducts are connected with the burners by short pipes that may.

supply mains away from the heat of the furnace. In the following description the furnaces will be described as having burners using gas as a fuel. It is to be understood, however, that any type of burners using gas or oil as a fuel could be used if desired. It is only necessary to supply the proper fuel to the ducts.

The various features of novelty which characterizemy invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objects attained with its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

' In the drawings:

Figure 1 is a side view of a furnace in which the invention is incorporated;

Figure 2 is a view taken on line 22 of Figure 1;

Figure 3 is a view of a different type of furnace incorporating the invention;

Figure 4 is a view on line 4-4 of Figure 3; and

Figure 5 is a view similar to Figure 4, but showing a modification.

Referring to Figure 1, there is shown, for example, a barrel-type furnace l of the kind forming the subject matter of Hess Patent 2,529,690, issued November 14, 1950. A furnace of this type is generally cylindrical in shape and is provided with ends 2 each of which is provided with an opening through which the work passes continuously from one end to the other. Between the ends there is formed a substantially cylindrical furnace chamber. Furnaces of this type are constructed in accordance with ordinary furnace practice in that they comprise a metal shell 3 that is lined with layers of refractory material 4 and 5. The refractory material 4 may well have insulating properties to retain the heat of the furnace while the refractory 5 is of a composition which will'withstand the high temperature that is produced in the furnace chamber. The shell is provided at its upper surface with vents 6 that connect with the furnace chamber, and is provided in its lower portion with openings I through which scale and other dirt may be removed. The furnace itself is mounted on suitable supports so that it will be held at the desired distance above floor level.

Surrounding the furnace throughout a major portion of its circumference are a plurality of structural reinforcing members 8, 9 and l I which, in this case, take the form of channel members that are welded to the shell 3 at the outer edges of their flanges. The ends of the channel members as shown herein do not extend across the top of the furnace, but they could do so if desired. When the reinforcing members do not extend completely around the furnace as shown herein the ends of the channel members are closed by suitable plates l0 welded to their ends and to the shell 3 of the furnace.

The furnace is heated by a plurality of burners l2 that are inserted through the shell at spaced points lengthwise thereof and around the air- .cumference of the furnace. As shown herein, by way of illustration, the burners are of the nozzle mixing radiant type forming the subject matter of Furczyk Patent 2,561,793, issued July 24, 1951, and using gas as the fuel. Each burner comprises a casting [3 into which fuel and air are supplied separately anda portion l4 projecting into the furnace through a suitable opening formed therein. This portion is provided with means in which the air and fuel are mixed so that a complete mixture of fuel is discharged radially from the end of the projecting portion i into the furnace chamber. In a burner of this type the projecting portion extends into a tunnel block l that is built into the refractory material 4 and through a burner block it that is placed in the refractory material 5 and which forms a portion of the furnace wall. The block it has a substantially conical depression I! in its surface into which the projection M extends and against the surface of which the combustible mixture burns in a manner set forth in detail in the above-described Furczyk patent. The burner is fastened in place on the shell 3 of the furnace by means of bolts l8 which extend through a flange on the casting l3 and are threaded into the shell.

The air intake to the casting 13 of each burner is connected by means of a flexible joint 5&1 to a pipe 2i. These pipes are welded at their other ends to either channel '8 or II. depending upon the location of the particular burner. The channels are provided with openings so that the interior of the pipes are in communication with a duct 22 formed by each channel and the metal shell 3 to which that channel is attached by its flanges. The fuel inlet of the casting iii of each burner is connected by a flexible coupling 23 with a pipe 24 that is welded to the outer surface of reinforcing member 9. The pipes connected with burners on opposite sides of channel 9 extend in opposite directions as shown in Figure 2.

Member 9 is provided with openings so that the interior of each pipe is in communication with a duct 25 formed by the channel member 9 and the surface of the metal shell 3. Fuel is supplied to the duct 25 by means of a pipe 26 which extends between the member 9 and a gas main 2'!. In a similar fashion air is supplied to the ducts 22 formed by the members 8 and I I through pipes 28 and 29, respectively, which are connected with an air main 3!.

From the above description it will be seen that reinforcing members of the furnace and the wall thereof, which actually form part of the furnace structure itself, are used to form ducts through which the fuel and air are supplied to the burners. By this arrangement each of the burners can be connected with the fuel supply through a minimum amount of piping that is practically free from joints. The pipes 2i and 24 can be located with respect to and connected with the channel members with the use of jigs, thus reducing the time and cost of assembly.

When any temperature control of the furnace is required the valves for such control regulating the flow of air and gas to the burners can be placed in the mains 21 and SI respectively in a position which is remote from the furnace. This means that the valves are not subjected to the heat of the furnace and will, therefore, be more reliable in operation. The construction disclosed provides a neat arrangement of piping between the supply mains and the burners themselves. Since most of the connections can 'be welded there is little chance for leakage to occur and, therefore, maintenance of the system is reduced to a minimum. Furthermore, the construction described is considerably cheaper to install than is the conventional piping in which separate manifolds are used for each of the groups of burners with separate pipes running to each burner. This is particularly true when a burner of the type shown herein is used since each burner I requires a plurality of connections.

A further advantage obtained with the present construction is that of a certain amount of heat conservation. As the fuel and air flow through the ducts they have a cooling effect on the furnace shell. This cooling of the furnace shell has the tendency to prolong its life. The heat picked up by the fuel and air from the furnace shell serves to preheat them prior to their introduction into the furnace. Thus, the heat obtained by cooling the shell is put back into the furnace in the form of pre-heated fuel to produce higher flame temperatures.

The type of construction described above can also be used to advantage with other types of furnaces. For example, the use of the invention with a box-type furnace is shown in Figures 3 and 4. The furnace is shown as being supported by structural members 4|, and as having the sides backed up by a metal shell 42. Plates forming the shell are reinforced to increase their rigidity by structural members shown herein as angle irons 43 and '54 extending lengthwise of the furnace. The interior of the furnace is built up in the usual manner of layers of refractory material 45 and 4B, the outer of which can have insulating properties while the inner layer is heat resistant. One end of the furnace is provided with an opening leading to the chamber thereof, which opening is shown as being closed by a door 41 that can be raised or lowered by any suitable mechanism including a cable 48 to give access to the furnace chamber.

Furnaces of this type are provided with a plurality of burners which burners are generally duplicated on each side. As shown, there are 8 burners in the side of the furnace, each of which includes a portion 49 outside of the furnace and to which the fuel is supplied and a distributor member 5| extending through an opening in the wall of the furnace to the chamber thereof. The burners are fastened in position on the shell 42 by suitable bolts 52. The burners may be of any type, but are shown herein, by way of example only, as being of a type disclosed in Hess Patent 2,215,079, issued on September 17, 1940, and are supplied through a single pipe with a complete mixture of fuel and air. Burners of this type have a tunnel block 53 and a burner block 54 which are embedded in the refractory material forming the lining of the furnace. As shown herein, the burner block is provided with a cup-shaped depression 55 into which the distributor 5| extends. In the operation of burners of this type a combustible mix-'- ture of fuel and air is supplied to the burner and flows through the distributor member 5| into the cup 55 of the burner block where it is discharged in a plurality of radially directed jets. These jets are ignited and burned within the cup in a manner fully described in the above-mentioned patent.

Fuel is supplied to the portion 39 of the burner through pipes 55 which may be provided with a valve 51 if it is so desired. These pipes are in communication with a duct 58 through which the combustible mixture is supplied, which duct is formed by welding a strip of material. 59 to the upper edges of the reinforcing angle irons 43 and 44. The ends of the duct would be closed by suit able means such as the plates is in Figure 1. Fuel is supplied to the duct 53 by a pipe 6| that extends between the duct and the fuel supply main 62. It is noted that the angle irons and plate used in this embodiment are the equivalent of the channel members 8, Band II of Figure 1.

In each case the structural members and the furnace wall are used to form a fuel conveying duct that is an integral part of the furnace. In many cases additional reinforcing members besides those shown will be used on the furnace walls. These members may be used to form additional ducts if it is desirable to have the burners of each row supplied separately.

In some cases, where additional reinforcing members are not available, it may be desirable to supply the upper and lower burners at different rates. In such a case a construction of the type shown in Figure 5 may be used. In that figure a third member 63 of angular or other shape is attached to the metal shell 42 of the furnace to form a partition between the reinforcing members 43 and 44. When the strip 59 is welded to the reinforcing members the partition 63 divides the space into two small ducts 58a and 5812 respectively, so that fuel can be supplied individually to the upper and lower rows of burners. In this case sup-ply pipes 5| will be connected between each of the ducts 58a and 58b and the supply main 62.

In the operation of the furnace fuel is supplied through the'main 62, pipe 6|, duct 58-and pipes 56 to the burners. Any suitable temperature control arrangement may be used to control the supply of fuel through the main 62. If an arrangement of the type shown in Figure 5 is used it will be necessary to have control valves in each of the pipes 6| rather than a single valve in the main 62 since, in this case, the burners are to be supplied with fuel at different rates.

It will be obvious that a partition could be placed in the duct 58 of Figure 4 so that the burners in the front portion of the furnace could be supplied separately from the burners in the rear portion of the furnace. It will also be apparent that air could be supplied to one of the ducts 58a or 58b and fuel could be supplied to the other if burners of the type shown in Figure 1 were used in the furnace of Figure 5. If burners of the type shown in Figure 3 are used in the furnace of Figure 1, ducts formed by members 8 and H or member 9 would be used to supply the fuel mixture while the other duct would not be used for the supply of fuel.

The reinforcing members of the furnace structure as well as the outer wall of the furnace itself are used to form the supply ducts for the fuel leading to the furnace burners. By an arrangement of this sort the piping for the various burners is considerably simplified since manifold supports as well as the long pipes to each of the burners from the manifold, as is conventional, are done away with. Since the ducts form a part of the furnace, expansion problems in the piping are substantially eliminated. The arrangement disclosed herein provides a neat, inexpensive and simple manner of carrying the fuel from a point of supply to the burners. Because of the short run of pipe that is possible between the supply duct and the burners themselves fewer joints are necessary in the supply pipes with a consequent reduction in the chance of developing a leak in the system. Furthermore, the reduction in the number of pipe fittings and joints that are necessary between the fuel supply and the burners reduces the cost of constructing a furnace of this type.

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me it will be apparent to those skilled in the art that changes may be madein the form of the apparatus disclosed Without departing from the spirit and scope of the invention, as set forth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

What is claimed is:

1. The combination of structure forming a fur-' nace including a shell having end walls and continuous side wall extending therebetween on the outside of the furnace, elongated U-shaped reinforcing means extending along the exterior of said side wall of said shell, means to fasten the legs of said U-shaped reinforcing means tosaid shell to form a duct with said shell as a wall thereof, burners for said furnace extending through said shell adjacent to said reinforcing means, means to supply fuel for the burners to the duct formed by said reinforcing means and shell, and connecting means between said reinforcing means and each burner through which the fuel can flow from the duct to the burner.

2. The combination of structure forming a fur-' nace including a shell having end walls and a continuous side wall extending therebetween and surrounding the furnace, a pair of elongated channel shaped reinforcing members extending along the exterior of said side wall of said shell, means to attach said members to said shell by the flanges thereof and in substantially parallel relation, said members and shell forming ducts, a plurality of burners adapted to extend through said shell into said furnace, means to fasten said burners in position between said pair of channel members, conduit means to connect each burner with the duct formed by the channel member on each side thereof, means to supply fuel to the duct formed by one channel member, and means to supply air to the duct formed by the other 7 channel member.

3. The combination of structure forming a furnace and including a metal shell having end walls and a continuous side wall extending therebetween on the exterior of the furnace, an elongated channel shaped reinforcing member extending along the exterior of said wall of said shell, means to attach said reinforcing member by its flanges to said shell to thereby strengthen the same and also to form a duct, means to close said duct at each end of said member, a plurality of burners extending through said shell. into the furnace, conduit means connecting said burners with said duct, and means to supply fuel for said burners to said duct, from which it flows through said conduit means to said burners.

4. The combination of claim 3 in which said furnace is cylindrical in shape and said channel member extends circumferentially around said shell.

5. The combination of structure forming a furnace and including a metal shell on the outside of the same, a plurality of angular reinforcing members attached by one side to said shell and extending parallel and adjacent to each other, a plate exetending between and attached to the other side of each of said members to form with said members and shell a duct on the surface of said shell, a plurality of burners each having a portion extending into the furnace and a portion outside of the same, means to fasten said burners in position on said shell, a pipe running from the duct to the portion of each burner outside of the furnace, and means to 7 supply fuel to the duct whereby it may flow to the burners.

6. The combination of structure forming a furnace and including a metal shell on the exterior thereof, a pair of angle irons, means to attach said angle irons in parallel spaced relation to said shell by one side thereof, said angle irons extending along the shell to reinforce or stiffen the same, a plate, means to attach said plate at its edges to the edges of the other sides of said angle irons whereby a duct is formed by said shell, angle irons and plate, a plurality of burners for said furnace, conduit means extending between said duct and each of said burners, and means to supply fuel for said burners to said duct.

7. The combination of claim 6 including partition means extending between said plate and said shell to divide said duct into a plurality of sections, some of said conduit means extending into one section of said duct and other of said conduit means extending to another section of said duct.

8. The combination of structure forming a furnace having a chamber and including a shell having end walls and a continuous side wall extending therebetween on the exterior of the furnace, a pair of elongated U-shaped members,

means to fasten said members by the legs of the U to the exterior of said side wall of said shell, said members extending along the exterior of said side wall of said shell substantially parallel to each other and forming with the shell a pair of ducts, a plurality of burners, means to mount said burners on said furnace to heat the chamber thereof and with a portion of each burner extending through said shell between said U- shaped members, conduit means connecting each burner with the duct formed by each member,

means to supply fuel for the burners to one duct,

and means to supply air for the burner to the other duct.

References Cited in the file of this patent UNITED STATES PATENTS

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