US2096695A

US2096695A - Furnace construction

Info

Publication number: US2096695A
Application number: US122855A
Authority: US
Inventors: Samuel A Forter
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-01-28
Filing date: 1937-01-28
Publication date: 1937-10-19
Anticipated expiration: 1954-10-19

Description

Oct. 19, 1937. s. A. FORTER 2,096,695

FURNACE CONSTRUCTION Filed Jan. 28, 1937 s Sheets-Sheet 1 INVENTOR Oct. 19, 1937. s, A, PORTER 2,096,695

FURNACE consmuc'r ion:

v Filed Jan. 28, 1937 3 Sheets-Sheet 2 l/ I I Ii II I I I INV ENTOR M 4 #mw ATTORNEYS Oct. 19, 1937. s. A. FORTER FURNACE CONSTRUCTION Filed Jan. 28, 1937 3 Sheets-Sheet 3 I I III INVENTOR ATTORNEYS.

PM a. 1a, 1931 PATENT OFFICE.

2.00am, 'ruamca cons rauc'rron Samuel A. Porter, Beilevue, Fa.

Application January .28, 1937, Serial No. 122,855

Claims. (Cl. 263-) My invention relates to industrial furnaces of the regenerative type, and consists in refinements in furnace construction, by virtue of which more efficient operation is obtained, and economy in construction and maintenance realized.

'Ihe'invention, more particularly, consists in' an improved port for firing regenerative furnaces with liquid fuel, and in a particularly effective organization of such port with the regenerator and fuel-feeding apparatus of the furnace.

By way of illustration and not limitation, the invention will be described as it is advantageously embodied in a glass furnace, and in the accompanying drawings Fig. I is a view of such a furnace in longitudinal, vertical section; Fig. II is a view 'of the furnace in horizontal'section; Fig.

@ III is a fragmentary view, to larger scale and'on the same plane of section as Fig. I, of one of the firing ports of the furnace; and Fig. IV isa view comparable with Fig. III, illustrating certain modifications in the construction of the firing port and in the organization of the port with the furnace.

Referring to the drawings, the furnace consists in a hearth i, vertical side walls 2,

end walls

3 and 3a, and a vaulted roof 4, all constructed of refractory masonry and externally reinforced in usual way with steel stays and tie-rods. Two ports 5 and 5a open through the vertical end wall 3, and the opposite vertical end wall 31:, extending on the arc of a circle between the side walls 2 (as viewed in plan in Fig. II) includes a plurality of doors 40 through which glass-forming materials are charged into the furnace. Regenerator chambers 6 and 6a are provided; in known way each chamber includes a body of refractory checkerwork I, and the ports 5 and 5a communicate with the chambers 6 and 6a, respectively, above the bodies of checkerwork included. therein. Fuel and air are introduced to the furnace through one port, while the products of combustion are removed through the otherythat is, one port serves as the firing port while the other serves as the outgo port. The combustion-sustaining column of fuel and air springing from the firing portthe port 5a in Fig. IIsweeps over the hearth l, circles at the opposite end of the furnace, as indicated by the arrows in Fig. II, and

\ thence flows to the outgo port-the port 5 in this chamberi is heated. From time to time, the direction of fiow is reversed, and the port which had been serving as the firing port becomes the outgo port, while the port which had been the outgo port becomes the firing port. That is to say, the port Ia becomes the outgo port, and air and fuel are fed into the furnace through port I, 5 the air being led upward through the hot checkerworlr in regenerator' 6 and preheated. All this is common practice, and further mention of known details of construction andoperation are unnecessary to an understanding of the inven- 10 Whereas, in the furnace illustrated in the drawings, both parts are arranged at one end of the furnace chamber, it will be understood that it is common in the art to arrange the ports in 15 opposing relation, one at each of the opposite ends of the furnace, in such manner that combustion progresses from one end of the furnace to the 1 other. Again, the ports are sometimes arranged at the sides of the furnace, in such manner that 20 the burning column (or columns) of fuel sweep across, rather than longitudinally of, the furnace hearth. Upon considering the ensuing specification, it will be understood that my invention may be embodied in any of such regenerative furnaces. 25

It will be noted that the regenerators 8 and 6a are horizontally spaced a relatively great interval from the endwall 3 of the furnace chamber, and that the ports 5 and 5a, severally extending from the regenerators to the furnace chamber, 30 bridge the horizontal interval between the regenerators and the furnace wall. In the interval or space between the regenerators and the furnace, and beneath the ports 5 and 5a, fuel-introducing apparatus A is arranged, and below apparatus A a 35 walk 8 (Fig. I) is provided, so that the furnace attendants may readily go beneath the ports while the furnace is in service. This space provides an operator's station, in which an attendant may observe at close hand the conditions of oper- 0 ation both within the port and the furnace, and make the required adjustments.

In Figs. I and III, it will be noted that the checkerwork in regenerators 6 and 6a extends upward a substantial interval above the level of 45 the floor or hearth I of thefurnace chamber, and that the passages or throats 9 within the ports communicate with the regenerators immediately above the checkerwork I included therein. By

virtue of such organization, I eliminate the usual ,uptakes, and obtain less turbulent flow of air and waste gases. The air for combustion, rising through the checkerwork I, immediately enters the firing port and is directed throughpassage 9 into the furnace, while the hot products of combustion streaming into the outgo port immechamber. The floor I when the port is operating as portion l3 extends'upward from the lower floor portion I! to the upper fioor portion ii and between the forward face of wall portion II and the furnace chamber is a cracking zone Z-a region into which in accordance with my invention liquid fuel is introduced, and in which such fuel is extends through wall portion II, and through this inlet a nozzle J 5, included in the fuel-feeding apparatus, is adapted to jet liquid fuel, .that is, the firing port of the furnace.' As shown, the nozzle "is efi'ec- .tive intermediate the opposite ends of the port for jetting the liquid fuel into the cracking zone Z, at a point beneath the column of air streaming through passage 9 and into the furnace chamher, and it will be perceived that the direction of flow of the jet, as considered in plan from above, is substantially parallel to such. column of air. Several glass furnaces have been built and operated in accordance with my invention, and it has been found that the of travel through zone Z is broken down, gasified and ignited. This breaking down, gasification, and initiation of combustion of the fuel in the zone Z withinthe port is of great practical advantage: greater efliciency. of combustion is obtained, turbulence of flow is minimized, and a more accurate control of combustion across the hearth of the furnace is possible. While I say that the liquid fuel is gasified in the cracking zone, I do not mean that a complete gasification of the fuel is effected within the port, but rather such gasification as will promote the good results obtained. It will be understood that in my port a preliminary mixing of fuel and air occurs inthe cracking zone Z, and that the usual deleterious effects of abrasion and temperature incident to the combustion of the streaming fuel are localized upon the floor portion i 2, rather than on the other wall portions of the port.

The fioor portion I2 is of flat, unspecialized shape, and may be economically constructed of highest grade refractory material. It is accessible beneath the port for ready repair and renewal.

The air flowing downward through the throat 9 into the furnace chamber spreads laterally, and forms a curtain of air over the burning column of fuel springing from the cracking zone Z and sweeping over the hearth of the furnace.

As has been already mentioned, my port is particularly designed for the combustion of liquid fuel. My port is to be distinguished from ports in which the fuel is jetted immediately into the furnace chamber, for such ports do not operate with liquid fuel with the desired efllciency-turbulence is great, and the desired control of combustion across the hearth is not obtained, The port of this invention is manifestly distinguished from known structures'in which the fuel is injected through the side walls of the port in a direction more nearly normal than parallel to the streaming air. Such known structures may operate well with gaseous fuel, but are impractical broken down, gasified and ignited. An inlet herein illustrated. It will be furnace roof 4 slopes downward from the end wallliquid fuel in its course such block for liquid fuel, unless modified in such manneras to produce the results I have described.

While my port is especially designed for firing with liquid fuel, it can be used with good results in gas fired furnaces, particularly when the port is embodied in a furnace having the structural features described below. I

In the operation of P rts vances from the firing port toward the opposite end of the furnace, the burning fuel rises and is progressively mixed with the air above. And as the flaming column approaches the outgo port, the air last" remaining in the curtain enters into the combustion of the fuel, whereby only hot products of combustion flow into the outgo port. The use of my port structure is particularly advantageous in a return fiow'furnace of the sort perceived that the I towards end wall 3a. Conveniently, the sloping effect is obtained by forming the roof'in a plu-= rality of arch sections 4a, 4b, 4c and id, as shown in Fig. I. The arch sections are successively stepped downward from the furnace towards the charging end (3a). The natural tendency of the burning gases sweeping through the furnace is torise, and, advantageously, the sloping roof operates against this tendency. As the burning column advances from the firing port to the opposite end of the furnace chamber, the curtain of air above is progressively urged downward by the sloping roof, whereby conditions of combustion are improved, and the advancing and burning columnof gases is caused to hugf the furnace charge from one end of the hearth l toithe other. As the progressively burning and expanding gases circle the end la of the furnace chamber and stream toward the outgo port 5, the effect of the sloping roof is opposite; that is, the roof operates to relieve the pressure on said air curtain, and promotes or facilitates the expansion of the streaming gases.

port end (3) of the Another feature remains for consideration. It

posed between the nozzle and the wall portion l3 of the port a block or slab i6 of relatively hard refractory'material, of. Figs. II and III, and in I provide an orifice l1 aligned with the inlet M. The relatively hard body of the block surrounding the orifice l1 resists erosion, and tends to hold the effective area of the inlet l4 to desired value. Thus, the quantity of air from the outer atmosphere which is aspirated into inlet II by the fuel jet remains constant, other things being equal.

It will be understood that the slab i6 is mounted in readily removable assembly with the wall portion l3, so that, as in time the body of block it is eroded and the orifice l1 unduly enlarged, a new block may be quickly substituted, without shutting down the furnace for an objectionable of the furnace, and the port 50 extends in bridgingrelation from the top of regenerator to the furnace. In this modified structure, as in the structure already described, the fuel-introducing apparatus is arranged beneath, and intermediate the opposite ends of, the port, and is adapted to introduce the fuel, either liquid or gas, through an inlet I40 in a wall portion I30 that extends approximately vertically between the two floor portions H and I20 of the port. The port includes a cracking zone Z, and functionally the modified port is substantially identical with the port first described. structurally, the modifications are not great-the passage or throat 90 of the modified port is in the form of a short gooseneck, as illustrated, and the vertically extending wall portion I30 is shortened.

All fuel-delivering equipment is arranged outside of my furnace and port structure, in such position that it is readily accessible for inspection and adjustment. The usual insulation for such equipment is dispensed with, and the fuel flowing through the equipment is not subjected to high temperature until it enters the furnace port 5. Lower fuel-feeding pressures may be employed. There is no divided fiow of air in the firing port, nor of the products of combustion in the outgo port-the passages between the regenerators and the furnace chamber are unobstructed. Persons skilled in the art will appreciate the value of the features described.

The application for this patent comprised a continuation in part of application Serial No. 103,967, filed October 5, 1936.

I claim as my invention:

1. A return-flow furnace including a furnace chamber and twoports arranged at one end of such chamber, a regenerator including checker- Work extending upward to a substantially higher level than the floor of said furnace chamber, one of said ports being adapted to serve as a firing port while the other is serving as an outgo port, said ports including passages communicating with said checkerwork, the passage of said firing port extending from substantially the top of said checkerwork for directing a column of air into said furnace chamber; said firing port including an upper floor portion, a lower floor portion, and a wall portion extending vertically between said floor portions intermediate the opposite ends of the port, an inlet extending through said upwardly extending wall portion, a nozzle for jetting liquid fuel through said inlet and into the port above said lower floor portion and beneath the column of air streaming there through, said liquid fuel being broken down and combustion initiated within the port, whereby a burning column of fuel with a curtain of air above is projected from said port, caused to circle the opposite end of the furnace chamber, and then flow to said outgo port, an orificed member interposed between said liquid-injecting nozzle and said upwardly extending wall portion, said orificed member being mounted in readily removable assembly with respect to said wall portion, with the orifice of such member arranged to define the effective area of said inlet through which the liquid fuel is jetted, said furnace having a roof sloping downward from the portincluding end of the furnace chamber to the opposite end, whereby, as the burning column streams from said firing port said curtain of air above is progressively urged downward upon the streaming and burning fuel below.

2. A regenerative furnace port including an upper floor portion, a lower floor portion, and a wall portion extending vertically between said floor portions intermediate the opposite ends of the port, an inlet extending through said wall portion, a nozzle for jetting fuel through said inlet, and a member interposed between said nozzle and said wall portion and including an orifice opening on one side of said member into the outer atmosphere and on the opposite side into said inlet, said orificed member being mounted in readily removable assembly with respect to said wall portion, with the orifice of such member arranged to define the effective area of said inlet through which the fuel is jetted with air drawn from the outer atmosphere.

3. A return-flow furnaceincluding/two ports arranged at one end of the furnace chamber, regenerators including checkerwork severally communicating with said ports, one of said ports being adapted to serve as a firing port while the other is serving as an outgo port, means for directing a burning column of fuel from the firing port into said furnace chamber and a passage extending through said firing port for directing preheated air into the chamber and forming an air curtain above the column of fuel as it streams from the firing port, circles the opposite end of the chamber, and flows to said outgo port, said furnace having a roof sloping downward from the port-including end of said chamber to the opposite end for gradually urging said curtain downward upon, and progressively forcing air into, the streaming fuel below.

4. A return-flow furnace including two ports arranged at one end of the furnace chamber, re generators including checkerwork severally communicating with said ports, one of said ports being adapted to serve as a firing port while the other is serving as an outgo port, means for directing a burning column of fuel from the firing port into said furnace chamber and a passage extending through said firing port for directing preheated air into the chamber and forming an air curtain above the column of fuel as it streams from the firing port, circles the opposite end of the chamber, and flows to said outgo port, said furnace having a roof sloping downward from the port-including end of said chamber to the opposite end for gradually urging said curtain downward upon, and progressively forcing air into, the streaming fuel below, and then gradually relieving pressure from above upon the burning and streaming gases.

5. A regenerative furnace including a port having an upper floor portion, a lower floor portion, and a wall portion extending verticallybetween said floor portions at a. point intermediate the opposite ends of the port, fuel-injecting means arranged beneath the port, said vertically extending wall portion including in interchange,- able assembly a member having an orifice into which said fuel-injecting means are directed, said orifice opening on oneside of said member into the open atmosphere beneath the port and on the opposite side of such member-said orifice communicating with the interior of said port.

SAMUEL A. mama. 7