US1416990A - Furnace - Google Patents

Description

H. F. SMITH.

FURNACE.

APPLICATION FILED mac. 4. 1911.

gg Patented May 23, 1922.

3 SHEETSSHEET 1 WWW H. F. SMITH,

FURNACE.

' APPLICATION HLED DEC. 4, 1917. L%1] 9@ I Patented May 23, 11922..v

3 SHEET8-SHEET Z,

NTER H. F. SMITH.

FURNACE.

APPLICATION FILED DEC.4,1917.

gg Patented. May 23, 1922.

3 SHEETSSHEET 3.

$7M? gm [0%, W HAW/MM) r 1: it. an, or Lmrne'ron, onto; assrerron, BY mnsnn assreivrrnnrs, TO

THE GAS EAR-CH COMPANY, OF DAYTON, 0M0, A CORPORATION OF OHIO.

FURNACE.

Specification of Letters Patent. Patngnt edl .lway 23, 1922.,

Application filed Decemhert, 1917. I Serial No. 205,383.

To all whom it may concern Be it' known that I, HARRY- F. SMITH, a citizen of the United States of America, residing at Lexington, Richland county Ohio,

haveinvented certain new and useful Improvements in Furnaces, of which the fol= lowing is a full, clear, and exact-description.

Thls invention relates to furnaces and more particularly to regenerative furnaces of the type-adapted to utilize fuel in the form of gas or vapor.

One object of the invention is to provide a regenerative furnace which is extremely simple in form and therefore quite easy of construction, and in which the complicated reversing mechanism in ordinary useis supplanted by mechanism which is not only easy' and inexpensive of installation, but which is also adapted to cause a minimum of trouble during its operation and maintenance. 7

Other objects and advantages will be apparent from the description set out. below,

.when taken in connection with the drawing.

The principal objection to the regenera tive' furnaces now in use arises from the complexity of the reversing valves, and the operating mechanism co-operating therewith, and from the great expense necessarily involved in installing such furnaces. In carrying my invention into effect, I so construct the furnaces that the furnace structure is itself simplified and by such simplification the necessity for valve mechanism for controlling the flow through the regenerators andstacks entirely obviated. For securing this result I pass the fuel, 'gasor vapor, under pressure, into the working chamber through elongated passages which connect the regenerators to opposite ends of the working chamber. The arrangementof the passages and nozzles is such that they constitute in effect injectors, the flow of fuel along a passage way inducing a corresponding flow of air from the co-operatmg regenerator to the worklng chamber,

wherein the mixture is burned. The regen erators have at all times unobstructed com-- munication with the air and, as aresult of.

the flow of gas and of air, from one of the regenerators, across the workin being unimpeded, the heate prodnets of combustlon pass freely upwardly throu h the other regenerator imparting heat t ereto. In a furnace of this type rechamversal of the flow therethrough is brought about by directing the supply of fuel from one nozzle to the. other. ture thereversing valves for controlling the regenerative chambers, aiong with the operating gear therefor, are entirely dispensed with, the only reversing valve used being a single three-way valve, of any desired type, for use in the gas line to control the point of application of the gas to the working chamber.

I have illustrated in the accompanying drawing a preferred embodiment of a regenerative furnace comprising my invention. In the drawing, in which like characters of reference designate like parts throughout the several views thereof:

Fig. l is a sectional view through the furnace along the line 1-1 of Fig. 2;

I Fig. 2 is a side elevation of the furnace;

Fig. 3 is'a rear elevation of the furnace showingthe reversing valve and one form In such a struc of mechanism for automatically operating In the drawing the numeral 1 designates generally a furnace resting upon a founder-- tion 2 of any desired construction and having co-operating therewith a stack or ventilator 3. This stack is not positively con-- nected to the furnace in any way, butin reality is nothing more than a ventilator or waste gas conveyor adapted to carry off, to the atmosphere outside the building housing the furnace, the waste gases constituting the products resulting from the combustion in the furnace.

Near the base of the-furnace is a working chamber 4 in which the fuel is burned, and in which any material to be treated is placed. Located above this working chamher are two regenerators 5 filled with checker brick work. Leading from the lower end of each regenerator 5 to the adjacent end of 'the'working chamber 4, is a' connecting passageway 6. The passageways Gas shown are inclined and any gases passing down one of them will sweep across the working chamber 4 and out through the other. In the top of each regenerator is a port 7 so located that gases passing upwardly therethrough will be caught by the stack3 and vented to the atmosphere. The

orts 7 are unobstructed so that each re en P a:

erator is at all times in free communication with the atmosphere. It is the usual practice to provide reversing valves for controlling these ports, but in my improved furnace flow through one regenerator intothe working chamber and thence upwardly through the other regenerator is induced by the flow of fuel. Consequently reversing valves for controlling the port 7 are unnecessary, the only valve needed being one for directing the flow of gas to each passageway 6. And any desired form of the three-way valve may be used for this purpose. I have shown the regenerators as located above the working chamber, but it is obvious that they might be just as advantageously located below. Where the regenerators are located above the working chamber, the natural draftthrough the apparatus will be a material factor in carrying the products of combustion upwardly there-' through, but where the regenerators are 10- cated entirely below the working chamber the pressure at which the fuel is fed must be sufficient to maintain a continuous circulation through the apparatus.

Passing through the walls of the furnace adjacent the point where each passageway 6 opens into the regenerator 5 co-operating therewith are gas supply nozzles 8. The number of passageways 6 connecting each regenerator to the corresponding end of the working chamber coincides with the number of gas nozzles used, a separate passageway being ordinarily used for each nozzle. Of course the number of nozzles to each passageway may be varied if particular circumstances demand. It is obvious that these nozzles arejust as well adapted for supplying liquid fuel, such as oil, in the form of spray and the invention is therefore not limited to a regenerative furnace adapted to use gas as a fuel, the furnace disclosed being capable of operating satisfactorily upon a variety of fuels. These nozzles are so arranged that any gas forced therethrough will flow axially or longitudinally of the passages 6 across the opening from the regenerators into said passages, the passages 6 and nozzles 8 constituting in effect injectors adapted, upon-passage through'either of the nozzles of gas under pressure, to withdraw air from the regenerator adjacent such nozzle and force the mixture of air and gas across the working chamber 4 from whence the products of combustion will pass up through the other passageway and regenerator and out through the port 7 thereof. It is evident that when gas is forced through .there. It is also evident that if gas under pressure continues to flow in through one of the nozzles 8 and the passage 6 co-operating therewith, the heated gas resulting from the burning in the chamber 4 of such gas will pass upwardly through the other passage (3 into the regenerator 5 co-operating therewith, giving up heat to the checker brick therein as it passes on its way to the port 7 and stack 3. If now the direction of flow of the gas is reversed, i. e., if the gas is directed into the passage 6 through the other nozzle 8, while the flow of gas through the first nozzle, and consequently through the first passage, is at the same time cut off, the direction of flow through the entire furnace will be automatically reversed. Under such conditions a flow of air will be induced through the other regenerator, which has been heated to a high temperature by the passage therethrough of the heated products of combustion, and because of the initial heat imparted to such air during its passage through the regenerator, the temperature in the working chamber at will be greatly increased. In order that the passages 6 and nozzles 8 shall give rise to an injector action, the longitudinal dimension of such passages must be greater than their transverse dimension, the greater the preponderance of length over breadth, within reasonable limits, the greater the injector action produced.

Because of their location the nozzles 8 are subjected to an extremely high temperature and thus tend to burn out very rapidly. To overcome this defect these nozzles are made of some metal, such as aluminum, which is a very good conductor of heat, and the outer ends thereof, which are exposed to the atmosphere, are provided with a series of radiating ribs or fins 9. These ribs or fins increase the radiating surface of that part of the nozzle exposed to the atmosphere, and, since the metal of which the nozzles are constructed is a very good conductor of heat. tend to'withdraw heat from the inner end thereof and radiate it to the atmosphere so rapidly that the temperature of the inner end of the nozzles is kept down and the tendency to burn them out thus lessened. Threaded into the outer end of each nozzle is a plug 10 adapted to carrytherethrough a threaded stem 11 the inner end of which co-operates with the opening 12 in the nozzle 8 to vary the effective area of that opening,

-upon movement of the stem 11 axially of thenozzle. lBy Varying the effective opening of the nozzles without any variation in the pressure of the gas supplied thereto, the velocity of the flow of gas may be varied. Since the inductive action on the air in the regenerators is dependent upon the velocity of the flow in the passages 6, the proportion of air to gas, in other words the composition of the combustible mixture fed to the working chamber, can thus be varied at will. And of course the amount of gas or vapor which can flow through the nozzles may be thus also varied. As shown in Fig. 2 1 prefer to use two gas supplying nozzles for each end of the working chamber 6, but it is obvious that this number may be varied as desired to meet particular conditions which may arise. It is only necessary that the gas supplying nozzles used have suflicient capacity to furnish the amount of gas needed for generating the desired temperature in the working chamber 4 and that the rate of flow of gas through these nozzles be sufiicient to induce the necessary fiow of air through the regenerators.

From the above description it is quite evident that the structure of the furnace is greatly simplified, inasmuch as the reversing valves which ordinarily control the regenerative chambers are completely dispensed with, and it becomes merely necessary to provide a single valve for controlling or directing the flow of gas to either set of nozzles 8. Mechanism for automatically directing the fiOW.Of gas to either set of nozzles is shown in Figs. 2 and 3. Leading from a source of supply of gas under pressure is a main 13 which leads into the casing of the three-way valve 14. Leading off from the valve 14 are two branch ipes 15, each of which is, adapted to su p y gas to one of the sets of nozzles 8. v igidly attached to some part of the apparatus adjacent valve 14 is a motor 16 adapted to drive a train of .reducing gears 17, 18 and 19. Attached to the gear 19 is a crank 20, the free end of which is operatively connected to one end of the rod 21 which has its other end in turn connected to the valve operating handle 22..

- driven by a clock or similar means and adapted at predetermined intervals to cause the passage of a current therethrough to bring about actuation of said motor and so of the valve. And it is obvious that by properly proportioning the gears 17, 18 and 19, and the timing mechanism 23, the movement of the valve 14 will be just sufficient to cut ofi'- the flow of gas through one of the pipes 15, and permit of the flow thereof felt through the other pipe 15. The valve shown generally at 14 is similar in structure to the valve described in my Patent No. 863,004, dated Aug. 13, 1907, but any other type of three-way valve desired maybe used in place thereof, the changes in the actuating mechanism made necessary by such substitution bein si'mple mechanical within the ability of any skilled mechanic.

By .making use of the valve actuating mechanism described above, the operation of this improved type of furnace can be made entirely automatic. And by properly connecting the valve actuating mechanism of a plurality of furnaces such as described, it is evident that a large number of such furnaces may be controlled from one central timing mechanism, so that the individual furnaces will be reversed in any desired order. Where such a plurality of furnaces are used, a master'timing mechanism for bringing aboutsuccessive reversals of the various furnaces is necessary. Otherwise it is conceivable that the flow of gas through all of The operation of such a furnace is not dependent upon the precise form of valve actuating mechanism disclosed, it being possible to substitute various other valve controlling devices therefor. One form of valve cont-rolling device that may be substituted problems, easily 4 for the form shown in Fig. 3, is illustrated in Fig. 5. As illustrated in that figure, 13 is a gas supply main which leads from a source of supply of gas under pressure and opens into the valve casing 24. This valve, like that shown in- Fig. 3, is also similar to the valve described in my Patent No. 863,004, dated Aug. 13, 1907. Opening from the casing 24. are two branch pipes 15 which lead to the nozzlesj8, and supply those nozzles with gas under presssure. Operatively connected to the valve operating handle 25 by means of a link 26 is a rod 27, the other end of which is connected to a piston '28 located in the cylinder 29.

Operatively connected to the operating handle 25 by means of a link 30 is a rod 31 which passes through the support 32, and is rigidly held against motion in any direction other than co-axial with the rod'27. The piston rod 27 is also restrained from any movement other than axial. Operatively connected to the upper end of the rod 31,

by means of the link 33, is a lever 34 ful-.

from the position shown in dotted lines at 36, its leverage rapidly decreases, and upon downward movement, its leverage rapidly increases.

Situated adjacent the cylinder 29 is a pilot valve casing 37, having two pipes 38 and 39 opening into opposite ends thereof. These pipes are branches of a pipe 40 which leads from a source of supply of air under moderate pressure, the pressure under normal working conditions being about six pounds. Located in the casing is a piston valve 41, normally urged toward one end of the casing by means of the spring 42. Attached to the other end of the valve 41 and extending co-axially through the end of the casing 37 is a rod 43 adapted to co-operate with the cam-bearing wheel '44, the spring 42 urging the valve 41 and rod 43 longitudinally of the casing 37 to cause the rod 43 to be in continuous working contact with the periphery of the cam wheel 44. Carried by the valve 41 are two peripheral ports 45 and 46, the port .45 being adapted upon proper positioning of the valve to register with the inlet pipe 39 and port 46 with the inlet pipe 38, but the positioning of these ports is such'that both of them can not be connected with both inlet pipes at the same time. I

Leading off from the casing at points substantially 180 degrees from the points of entrance of the pipes 38 39 are two pipes 47 and 50, while leading from the casing intermediate the'points of entrance of the pipes 38 and 39 are two exhaust pipes 4849. The pipes 4750 are so arranged that one of them is in connection with one of the inletpipes 3839 while the other is in connection with its corresponding exhaust pipe 4849. As shown in the drawing the pipe 47 is in operative connection with the pipe 39, and the air under pressure is led from said branch pipe 39 through the port 45,

and out through the pipe 47 while the pipe 50 is connected through the port 46 with its exhaust pipe 49 so that the pressure theretofore stored up in the pipe 50 and that part of the mechanism connected thereto may ex haust to the atmosphere. 7

The pipes 47-50 lead to opposite ends of a valve casing 51 having a valve 52, carrying a peripheral port 53, slidable therein. Carried by the ends of the valve casing 51 are inwardly extended stops 54,'adapted to main tain at all times a free space between each end of the valve and the corres ondiong end of its casing. The pipes 47 an 50 open into the casing 51 in such wise that any pressure fluid passing therethrough enters these free spaces between the valve and the valve casing. Opening into the casing 51, intermediate its ends, is an inlet pipe 55 connected to a source of supply of air under high pressure, a pressure of about 100 lbs. being used in actual practice. Leading of? from the valve casing are two pipes 56 and 57, the

former of which opens into the lower end of the cylinder 29, the latter exhausting to the atmosphere. The port 53 in the valve 52 is so arranged that the pipes 55 and 56 can be connected with each other and the pipes 56 and 57- connected with each other. The three pipes, however, cannot be connected to each other at the same time, nor can the pipe 55 be connected to pipe 57.

The operation of the device is as follows: The cam wheel 44 which carries thereon any desired number of cams, the number being dependent upon the desired frequency of reversals, is connected to a clock mechanism adapted to rotate such wheel at a predetermined rate of speed. As illustrated this wheel carries thereon four cams 58, there being necessarily four depressions 59 between such cams, which arrangement will give rise to eight reversals every revolution of the cam wheel. Ordinarily the cam wheel will be so arranged as to make one revolution an hour, so that with the number of cams shown in the drawing, there will be a reversal every seven and one-half minutes. As shown in the drawing the piston 28 and weight 36 are in extreme elevated position with the valve 24 in such position as to direct the flow of gas from the pipe 13 through the upper pipe 15. As the cam wheel rotates from the position shown to move the cam 58 out of contact with the rod 43, the valve 41 will be urged by the spring 42 longitudinally of its casing, the rod 43 moving into a depression 59. Upon such movement of the valve 41, the port 46 will connect the pipe 38 with the pipe 50, at the same time cutting off the exhaust pipe 49, while the port 45 will bemoved into such position that the pipes 39 and 47 will no longer register, but the pipe 47 will register with its exhaust pipe 48 to exhaust to the atmosphere the air under pressure in the righthand end of'the valve casing 51. As the air under pressure is beingexhausted from valve casing 51, a supply of air under pressure is passing through the pipe 50 to the opposite end thereof. As the pressure in the lefthand end of the casing preponderates, it will force the valve 52 longitudinally of the casing to close off connection between the pipe 55 and the pipe 56, and open connection between the pipe 56 and its exhaust pipe 57. The pressure air stored in the cylinder 29 below the piston 28 will thus be vented to the atmosphere, and the pressure within such cylinder thereby decreased. As this pressure decreases the piston 28 urged by the weight 36 will tend to fall, the leverage increasing during downward movement of the weight. With the pressure in the cylinder 29 greatly decreased and the moment of the force exerted by the weight 36 rapidly increasing, the cylinder will be forced down very rapidly. The valve 24 at the same time, because of its operating mechanism being connected to the piston and lever mechanism, will be rapidly shifted from one extreme position to the other to cut ofi' flow through the upper pipe 15, and permit -of flow through the lower pipe 15. And, of course, where one of the cams 58 moves into contact with the rod 43 it will force the valve 41 longitudinally of its casing, against the spring 42, to bring about a reversal of the above operation and thus connect the upper pipe 15 with the main 13 while closing off the lower pipe 15. It is obvious that this reversing 'mechanism lends itself just as readily to the control of a plurality of furnaces as does the mechanism illustrated in Fig. 3.

In Figs. 6 and 7 is illustrated still another modified form of mechanism for controlling the gas reversing valve. In the apparatus illustrated therein, 13 is the gas supply main which leads into a valve casing 60, having. two branch pipes 15 leading therefrom. Mounted within the casing 60 is a three-way disc valve which may be of any desired {conventional construction adapted upon rotation to connect either one .or-the other of the branch pipes 15 with the main 13. Itigidly connected .to the valve operating stem 61 is a disc 62 having two stops 63 thereon adapted to co-operate with a pawl 64.

This pawl is preferably held in contact with the dlsc 62 by means of a spring 65 and is adapted to normally hold the disc against rotation. Parallel to the disc 62 and adjacent thereto is a second disc 66. Rigidly attached to the disc 66 is a worm gear 67 in operative contact with a worm pinion v carried'by theshaft 68 of the motor 69.

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Located between the discs 62 and. 66, and having an end thereof attached to each, is a spring 70. The motor 69 is adapted to rotate continuously inhone direction, and, by

means of the worm' gearing,- to rotate in unison therewith the disc 66. Inasmuch as the disc 62 is normally held againstrotation by means of the pawl 64, rotation of the disc 66 will cause a winding up of the spring 70 to increase the tension thereof. Carried by the disc 66 is a lug 71 adapted during rotation of the said disc to contact with the pawl 64 to move that pawl out of engagement with the stop 63. When the-pawl 64 is thus moved the disc 62 acting under the influence of the spring 70, will rotate and during such rotation willfactuate the valve controlling flow through the casing 60 to open one of the pipes 15 and close the other. And, by

I properl proportioning the various parts of the actuatlng mechanism, reversals of the valve can be secured at any desired predetermined intervals.

From the above description it is obvious that I have invented a type of furnace in which are eliminated the objectionable features present in the furnaces now in use, a furnace which is not only capable of very easy operation, but is extremely simple in constitute in effect injectors drawing the heated air from the regenerators inproper proportion for mixture-with the fuel and forcing the resulting combustible mixture into the working chamber. My invention, however, is not limited to the precise structure and mechanical details described herein, inasmuch as numerous changes could undoubtedly be made without in any way departing from the spirit, or the scope, of my invention. or a true definition of the invention, therefore, reference should be had to the appended claims.

What I claim as new is:

1. In a regenerative furnace, a working chamber, air regenerators, valveless passages connecting said regenerators to the atmosphere, passages connecting said regenerators to the working chamber, nozzles for passing gas along said passages, and means for directing the flow of gas through the nozzles.

2. In a regenerative furnace, a working chamber; regenerators associated therewith; valveless passages connecting said regenerators to the atmosphere; a passage connecting each end of the working chamber to a regenerator; nozzles opening into the passages, said nozzles and passages constituting in effect injectors; means for suppyling fuel under pressureto either of said nozzles; and means associated with said nozzles and adapted, at predetermined intervals, to inoing without 5. In a regenerative furnace, a working chamber; air regenerators in open co1nmunication withsaid chamber, each regenerator having a valveless passageway into the atmosphere; and a partition separating the passageways to prevent the flow 0f fluid, in either direction, through one of said passageways aifecting the flow of fluid through an adjacent passageway.

In testimony whereof I aflix my signature.

HARRY F. SMITH.

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