US1730570A - Muffle furnace - Google Patents

Description

Oct. 8, 1929. F. 'c. GREENE ET AL I MUFFLE FURNACE 2 Shets-Sheet 1 Filed. June 13, 1925 Fan/la C (imam,

0 8, 1929- F. c. GREENE EI;AL 1,730,570

MUFFLE'. FURNACE Filed June 13, 1925 2 Sheets-She et 2 5106755115: 1 1127016 6'. G'reamfl,

Patented Oct. 8, 1929 UNITED STATES. PATENT OFFICE.

FRANK C. GREENE, OF WAUKEGAN, AND OTTO H. HERTEL, OF CHICAGO, ILLINOIS MUFFLE FURNACE Application filed June 13, 1925. Serial No. 36,787.

This invention relates to furnaces and particularly to a muffle furnace for heating one or more retort chambers.

The furnace is adapted for heating a primary chamber through which material is continuously passed for heat treatment and it may likewise be adapted for heating a secondary chamber, where the'material is lodged for a considerable time for annealing or other similar heat treatment.

The heat required by the primary chamber, of course, depends upon the process employed therein and the heat required may vary in difierent zones of the chamber. Likewise the heat required in the secondary chamber may vary according to the process in hand, such heat being different from that required in the primary chamber.

It is the object of the present inventionto provide a muflie furnace wherein the heat may be varied in zones to effect the required heating of the primary chamber.

Another object of the invention is to provide means for varying the heat of the secondary chamber as required and passing the waste heat therefrom toward the primary chamber.

A further object of the invention is to provide a combustion space having ports opening into a plurality of partitioned heating zones, said ports being provided with dampers to vary the port size in order. to change the heat in the corresponding zones.

A still further object is to provide the adj acent heating zones with movable partition sections therebetween so that adjacent zones may be opened into each other.

Another object of the .invention is to provide a furnace construction having movable walls therein adjustable in combination so that the furnace may be made an up-draft, a clown-draft, or a cross-draft furnace, wholly, or in part, or any desired combination of these three forms of heating.

Still other and ancillary objects and advantages arising from the particular construction employed will be apparent from the following description of an exemplary form of the invention, as disclosed in the accom- 50 panying drawings.

in the drawings we have illustrated afurnace embodying the invention as applied to an experimental coking oven in which coal is passed continuously througha tubular retort for carbonization and thence to a second chamber-for an annealing or soaking actionunder the further influence of the heat.

Figure 1 illustrates a front elevation of the furnace with one-half thereof shown in section along the line 1-1 of Fig. 2.

Fig. 2 shows a cross sectional view of the oven on the line 22 of Fig. .1.

Because of the varied heat zones which are required to use a coking apparatus in an experimental way, it is found desirable to provide a furnace of the type herein disclosed in which means are provided for rapidly varying the character of the operating arrangement of the furnace while either in or out of operation. v 1 i Referring first to the coking apparatus em ployed, there is shown atubular retort 10 in which a rotary screw conveyor 11 passescoal upwardly through the retort. The conveyor 11 is adapted to be driven by a stud 11 on which is mounted a gear 11 adapted to be connected to asuitable source of power (not shown). Coal is fed into the bottom of the retort by means of a second screw conveyor 12 located in a pipe length 13from the end of which the helical flights of rotor 11 pick it up. The coal is supplied in crushed form to the pipe 13 either through the'feed pipe 14 or the feed pipe 15 from a suitable upper supply, not shown. In the retort 10 the coal is subjected to heat to the extent desired and it is then passed as coke over floor 16 and incline 17 into a soaking chamber 18 likewise, subjected to heat as desired.

A single furnace is employed to heat the with a water seal 19, a closed inspection opening 20, and a gas outlet 21 entering into the hydraulic main 22.

Surrounding the retort 10 there is a furnace wall 23 of brick work substantially rectangular in form, the same'being supported by I-beams 24. The furnace wall is spaced from the retort 10 to form an annular heating chamber 25, which surrounds the retort 10. In the furnace wall 23 at vertical levels therein are fixed horizontal partition plates 26 projecting into the annular space 25, there being four such plates at each level 90 degrees apart. The plates all but touch the wall of the retort 10. The front and rear faces of the furnace are designated 27 and 28 respectively. In each of the faces 27 and 28 are positioned horizontally movable horizontal plates 29 which slide in and out of the furnace wall alongside of the front and rear fixed plates 26. Four such plates are shown which when fully inserted, as shown in dotted lines of Fig. 2, form an annular horizontal partition in conjunction with the fixed plates 26. Rails 30 and 31 are shown on the front and rear faces ofthe furnace upon which a ladder (not shown) may be mounted to permit an operator to move plates 29 to their properposition in the furnace.

A combustion space 32 is provided adjacent the left side of the retort. l rts 33 for each horizontal zone open into the combustion space. Horizontally movable vertical dampers 34 and 35 from the front and rear walls respectively are set into the corresponding wall openings 36 and 37, a handle 39 being provided for moving or drawing each damper. .A waste gas flue 40 is provided at the right of the retort, the coal feed pipe 14 passing therethrough. Exit ports 41 similar to the heat ports 33 are provided between the flue 40 and the annular space 25. Likewise, horizontally movable vertical plates 42 and 43 are located in the front and rear walls to close the exit ports 41. i r

The soaker 18 is surrounded or defined by brickwork 44 outside of which are a plurality of vertical lines 45 on the four sides. The tops of the fines open into a rectangular shaped passage 46 about the chamber 18, said passage being in communication with the combustion space 32 along the whole length of its right hand long side which is adjacent thereto. the fines 45 to supply heat therein as desired. A plurality of spaced secondary air ports 45 open into the fines 45 along the soaker 13. Likewise suitable fuel burning means 48 is located in the combustion chamber 32.

Adjacent the waste gas flue 40 are two heat recuperators, these constituting fines 49 and 50 in which a number of air carrying pipes 51 are located. The recuperator fines are connected at the top with the waste gas flue 40, and at the bottom each is connected separately through pipes 52 and 53 into a flue 54 Burners 47 are placed in leading to the stack. Dampers 55 and 56 are provided in the pipes 52 and 53. In the communication between the waste gas flue 40 and the recuperators horizontally movable vertical dampers 57 and 58 are provided. Suitable connections (not shown) are provided for leading the preheated air from pipes 51 to the burners 47 and 48 and to the muffle furnace Space 25.

In operation of the furnace, heat is generated by burners 47 and 48, the former heating the soaker chamber 18 and the latter supplying the remaining fuel required. The number of burners 47 which are employed is properly adjusted to the heat required for the soaker. The total heat generated is passed through any or all of the ports 33 to the annular space about the retort. The vertical dampers 34 and 35 are adjusted for the admission of the heat or gas into the various horizontal zones. On the opposite side the exit ports 41 are opened to the required de gree by moving the dampers 42 and 43. The horizontal movable partition plates 29 may or may not be opened as desired. With all the horizontal plates in closed position and all the vertical dampers opened, the furnace is divided into a plurality of horizontal zones or compartments making a cross draft heat on the retort 10. With the upper ports 33 open, the horizontal plates 29 drawn out, and the lower ports 41 open, the apparatus becomes a down draft furnace. With the lower ports 33 open, the horizontal plates withdrawn, and the upper ports 41 opened, the furnace is up-draft. It is obvious that various combinations of these may be employed, thus giving a wide range of heat to the various zones of the retort.

The combustion may be regulated so as to produce a greater heat in the central mufile furnace about the retort 10 than is produced in the combustion chamber 32 or the flues 45. By limiting the air supplied to the burners 47 and 48, the combustion will be incomplete and unburned gas will pass into the hori zontal compartments about the retort. By admitting air into this space the combustion can be completed and the heat intensified and localized as desired, thus adding further flexibility to the system employed. Air supply pipes 59 and 60 are provided for this purpose in the furnace walls with suitable distributing means 61 inside the furnace.

The waste gas flues 49 and 50, containing the recuperator pipes 51 may be constructed andoperated as regencrators if desired, such cpnstruction. and operation, however, having no particular relation to the furnace embodying the invention.

Other structures likewise may be used for other parts of the disclosed furnace, the drawings and description of which are not to be considered as a limitation of the invenlee tion short of the scope thereof as set forth in the appended claims.

o claim as our .invention:

1. A muflie furnace comprising, in combi-. nation, a retort to be heated, a wall associated with said retort forming a heating space, therefor, a plurality of fixed plates between said retort and said wall partially partitioning the space therebetween into zones along the retort, movable plates adjacent said fixed plates adapted in cooperation therewith to act as complete partitions for said zones, a heat supplying chamber outside said wall, a waste heat chamber on the outside of said wall opposite said heat supplying chamber, said wall having ports therein whereby the two chambers are in communication with each of said zones, and dampers to vary the openings of said ports.

2. A muffle furnace comprising, in combination, a retort to be heated, a heating chamber surrounding said retort, a heat supplying chamber adjacent said heating chamber on one side thereof, a waste heat chamber on the other side of said heating chamber, separating walls for said chambers having a plurality of ports therein placing said chambers in communication, and dampers located in said ports whereby the amount and direction of draught of heat entering and leaving the ports respectively to and from the heating chambermay be controlled 3. A muffle furnace comprising, incombination, a retort to be heated, a heating chamber associated with said retort, a heat supplying chamber adjacent said heating chamber, a separating wall between said chambers having ports therein, partitions having movable sections in said heating chamber adapted to divide the space therein into zones extending along the retort, and movable dampers placed in said ports, said dampers and said partition sections being movable to control the heat to said zones and to vary the relation of adjacent zones.

4. A muffle furnace com-prising, in combination, a retort to be heated, a wall surrounding said retort forming a heating space therefor, partitions having movable sections in said space adapted to divide the space into zones along the retort, a heat supplyingchamber outside of said wall and a waste heat chamber outside of said wall opposite said heat supplying chamber, said wall having ports therein communicating with said two chambers, there being one port from each zone to each of said chambers, and dampers in said ports adapted to Vary the opening thereof whereby to control the heat in said zones, the movable partition sections serving to vary the relation of adjacent zones.

5, A muffle furnace comprising, in combination, a retort to be heated, a furnace wall forming a heating space for said retort, partitioning means having movable sections di- 6. A muffle furnace adapted for primary and secondary heat treatment of material comprising, in combination, a primary retort adapted to have material pass therethrough, a second retort adapted to receive said material, means to heat the second retort, furnace chambers adapted to conduct the waste heat from said second retort to said first retort, auxiliary heating means for increasing the heat impressed upon said first retort, and means to distribute the heat at the first retort in a predetermined manner, a waste heat chamber adapted to receive the waste heat from said first retort, and pre-heating means in said waste heat chamber for the material entering said first retort.

7. A furnace comprising, in combination, a retort, a wall forming a heating space about said retort, a heat supplying chamber and a waste heat chamber outside of said wall, said chambers being on opposite sides of said retort, said-wall having a plurality of ports therein alincd along the length of the retort for-communication with said chambers to said heating space, dampers for said ports, and

partitions having movable sections adapted to divide the heating space into a plurality of zones alined along the length of the retort, there being one port to each zone from both of said chambers whereby when said retort is vertical the furnace may be used as an up draft, down draft, cross draft, and combination draft furnace according to the position of said dampers and said partition sections.

8. A furnace comprising, in combination, a vertical retort, a wall spaced therefrom to form a heating space about said retort, a heat supplying chamber, and a waste heat chamber outside of said wall and communicating with said heating space, said chambers being on opposite sides of said retort, means for supplying material to the lower end of said retort, additional heat supplying means extending through said waste heat chamber to said first mentioned means and being adapted to preheat the material before entcring the retort, means for conveying the material upwardly through said retort and for discharging the material from the upper end of said retort,

means for heating said heat supplying cham-- ber, a second vertical retort positioned alongside said heat supplying chamber, said last mentioned retort being adapted to receive the material discharged from said first mentioned retort, a wall forming a heating space about said last mentioned retort, the upper end of said last mentioned heating space opening into the upper end of said heat supplying chamber, and means for heating said last mentioned heating space.

9. A furnace retort comprising, in combination, a heating chamber, a retort in said heating chamber, means for supplying heat to said chamber, and a plurality of transverse partitions arranged longitudinally of saidretort and dividing the space in said heating chamber into a plurality of zones, each partition comprising a plurality of fixed plates spaced about said retort, and a plurality of movable plates disposed between the fixed plates and movable to open and close the space between the latter.

10. In a furnace retort, in combination with a heating chamber and a retort insaid heating chamber, a partition in said heating chamber, said partition comprising a pair of laterally spaced fixed plates extending laterally from the wall oi. said chamber to said retort, said plates being arranged ninety degrees apart, and a movable plate movable along one side of one fixed plate toward and from the other fixed plate to close or open the space between said fixed plates, the inner ends of said plates being shaped to conform to the transverse shape of said retort.

In testimony whereof we have hereunto affixed our signatures.

FRANK C. GREENE. OTTO H. HERTEL.

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