US2543150A

US2543150A - Sintering furnace

Info

Publication number: US2543150A
Application number: US778879A
Authority: US
Inventors: George C Burgess
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-10-09
Filing date: 1947-10-09
Publication date: 1951-02-27
Anticipated expiration: 1968-02-27

Description

Feb. I27 1951 G. c. BURGESS SINTERING FURNACE 4 Sheets-Sheet l Filed Oct. 9, 194'? m c QAM e mf/2 6 Feb. 27, 1951 G. c. BURGESS SINTERING FURNACE 4 Sheets-Sheet 2 Filed Oct. 9, 1947 ma `,i M Y,

Febo 27, 1951 G. c. BURGESS 2,543,150

SINTERING FURNACE Filed Oct. 9', 194'? 4 Sheets-Sheet 4 65.9017@ C Bul/aen- Patented Feb. 2?, QS.

UNITED STATES PATENT OFFICE SINTERING FURNACE George C. Burgess, Columbia, Tenn.

Application October 9, 1947, Serial No. 778,879

2 Claims. (Cl, 26S-21) This invention relates to a sintering furnace and has for its object the provision of a furnace of the character designated which shall be adapted to operate continuously, receiving a sintering charge of mixed fuel and material to be sintered, such as ore, and discharge the sintered material therefrom, which furnace shall be of large capacity, reliable in operation, and one which will not become overheated in operation.

A further object of my invention is to provide a continuously operating sintering furnace which shall include improved means to control the ignition and burning of the fuel in the sinteringcharge.

A still further object of my invention is to provide a continuously operating sintering furnace which shall embody a rotary drum having a gas permeable surface, with a stationary suction chamber disposed within the drum and with improved means to seal off the suction chamber from the greater portion of the drum and thus confine the feedingand sintering of the charge to a limited area of the drum.

Another object of my invention is to provide a continuous sintering furnace embodying a rotary drum with means to feed a sintering charge of ore and fuel onto the surface of the drum, means to control the rate of feed to maintain an even thickness of charge, and means to control the rate of combustion of the fuel in the charge thereby to prevent overheating of the furnace.

Apparatus embodying features of my invention is illustrated in the accompanying drawings forming a partof this application, in which:

Fig. 1 is an end elevational view;`

Fig. 2 is a plan view with parts broken away;

Fig. 3 is a sectional view taken generally along theI line IIL-III of Fig. 1; v

Fig. 4 is a sectional view, partly diagrammatic, taken generally along the line IV-IV of Fig. 3; and

Fig. 5 is a diagrammatic sectional View showing the means for controlling the rate of combustion on the drum.

Referring to the drawings for a better understanding o'f my invention, my improved apparatus embodies a foundation, or base plate, I Il having end supporting cradles II and I2 erected thereon, each having a semicircular seat I3 therein, as shown in Fig. l. Supported by the cradles in a manner to be described later isv my improved furnace which embodies a rotary drum indicated generally by the numeral I4. The drum is made up of end rings I6 and I1 joined together by a plurality of longitudinally extending bars I8.

Supported by the bars I8 are a series of grates I9 which form agas permeable surface for the drum to support the sintering charge of mixed fuel and ore thereon. Mounted on the end rings I6 and I1 are a series of extension rings 2I and 22 which extend entirely around the drum, as shown in Fig. 3, to provide lateral support for the sintering charge. The end rings I6 and I1 are provided with inwardly directed

flanges

23 and 24 having

grooves

26 and 21 therein in which are mounted

sealing rings

28 and 29. Each of the

rings

28 and 29 comprises outer rings 28a and 29a formed preferably of graphite, and inner rings 28h and 29h formed of steel or cast iron. Extending longitudinally of` the drum, and joining the inwardly directed

flanges

23 and 24 are a series of sealing strips 3|.

Mounted on the ends of the drum and secured i to the rings i6 and I1 are a plurality of

brackets

32 and 33 for supporting

riding rings

34 and 36, which latter are secured to the brackets. Mounted in the seats I3 of the cradles II and I2 are

roller bearings

31 and 36 on which the

riding rings

34 and 36 bear. The rollers of the bearings are retained by spacing rings 39 and 4I at each end of the drum. Also secured to the

brackets

32 and 33 inwardly of the riding rings 34 and 35, are

ring gears

42 and 43 each having its gear teeth on the inner surface thereof. vAt 44 I show a driving motor which drives a shaft 46 by means-of suitable sprockets and a sprocket chain 41. The shaft 46 extends entirely through the drum I4 and has mounted thereon pinions 48 and 49 which mesh with the ring kgears' 42 and 43 to drive the drum.

Mounted within the drum I4 is a stationary suction chamber comprised of end walls 5I and 52 and

side walls

53 and 54. The

side walls

53 and 54, as shown in Fig. 5 of the drawing, extend below the center of the drum I4 to form a trough 56. The trough 56 terminates in

flanged openings

51 and 58, extending through the end walls 5I and 52, to which are connectedsuction conduits 59 and 6I Mounted within the trough 56 is a screw conveyor having ribbon flights I62 .and 63 mounted on a shaft 64. As shown in Fig. 3, the

flights

62 and 63 are turned in opposite directions so that any solid matter passing through the grates I9 will be delivered out at the ends through the suction openings 59 and 6I. The shaft 64 is driven from the shaft 46 as shown in Fig. 2 of the drawing as by means of the belt 66 and

pulleys

61 and 68.

As shown in Fig. 3, the end Walls 5I and 52 are provided with inwardly turned flanges 69 and 1I which are concentric with the inwardly directed

flanges

28 and 24 of the end rings I 8 and I1 and cooperate with the

sealing rings

28 and 28 to prevent the flow of air into the suction chamber through the ends of the drum. Also, as shown in Fig. 4 of the drawing. the

side walls

58 and 54 of the suction chamber are provided at the top with

skirts

12 and 13 which are concentric with the drum and which are of such length as to span the arc between a pair of sealing strips 8|. Thus. one sealing strip always is cooperating with each of the

skirts

12 and 18 to intercept the ow of air into the suction chamber around the side walls thereof.

At the ends oi' the suction conduits 59 and 8|, respectively, are disposed cyclone separators 14 and '18 for separating from the gases of combustion any dust or solid material passing through the grate I9 into the suction chamber. Each of the cyclone separators is provided with a hinged weighted trap door 11, as shown in Fig. l, to discharge solid material therefrom when suilicient accumulates to open the trap door.

Connected to the

cyclones

14 and 16 are

suction conduits

18 and 19 which are in turn connected at their other ends to a single conduit 8| leading to a motor driven exhaust blower 82. f

The suction chamber, suction conduits, and cyclone separators, are supported by means of end supports 83 and 84 extending downwardly to the base or foundation plate I0.

The sintering charge, which, as is well understood, consists of a mixture of fuel and material to be sintered, is fed on the drum through a feed chute 86. the rateof feed being controlled as by a motor driven rotary feeder 81. As the charge falls on the drum, it is leveled oif by means of a leveling bar 88 extending across the chute 86 immediately above the drum. The charge is ignited by means of downwardly directed gas jets 89 and combustion is maintained by the air being drawn through the charge and the grate I9 by the blower 82.

The electric motor 9| for the feeder 81 is controlled by a switch 92 which is biased toward closed position by means of a-spring 93 and which may be opened by a solenoid 94 controlled by a circuit 96. One wire of the circuit 95 leads to a contact member 91 which is disposed to engage the top of the charge on the drum and the other wire leads to a contact 98 disposed to make sliding contact with the side of the ring 2| or 22. Thus when the charge onthe drum illls up to such an extent that the contact 91 engages in the charge, the circuit 98 is closed, the solenoid 94 is energized and the switch 92 is opened to stop the motor 9|, and thus stops the operation of the feeder '81 to supply charge to the drum. When the charge on the drum falls below the contact 91, the circuit 98 is then opened, the solenoid 94 is deenergized and the switch 92 is closed by the spring 93 to energize the motor 9|.

In order to maintain an even rate of combustion of the fuel in the charge and particularly to control the rate of combustion during the initial portion of the travel of the charge on the drum I4, I provide a baille I0| within the suction chamber which is pivoted at its upper end, as shown at |02. The lower free end of the baille is disposed to move toward the wall 54 by gravity. Connected to the lower end of the bafiie IIII on the opposite side from the wall 54, is a cable |03 leading to a drum |04, driven by a motor |06 through a suitable gear reduction |01. As shown in the drawing, the motor |08 is a reversing motor and -properly sintered, product.

in a manner which will be readily understood from the drawing. Located within the suction chamber between the wall 58 and the baille IOI is a capsule |09 containing a uid expansibly responsive to a rise of temperature within the suction chamber. A tube III leads from the capsule |09 to a, pressure responsive device, such as expansible bellows II2, connected by means of a rod II3 to the switch |08. Should the temperature within the suction chamber become too high, pressure within the capsule |09 will operate the bellows II2 to close the switch |08 and operate the motor |08 in a direction to swing the baille IOI with its lower end toward the side wall 53 of the suction chamber, thereby restricting the downward flow of air through the charge during the initial portion of the travel of the charge on the drum. Should the temperature within the suction chamber, between the baille |0I and the wall 53, fall below a predetermined minimum, the fluid within the capsule |09 contracts, causing the bellows I I2 to contract and operate the switch |98 to close and cause the motor to run in the opposite direction, whereupon gravity will cause the baiiie IOI to move toward the sidewall 54 and thus provide for a larger volume of air to flow through the charge. It is contemplated by my invention that the major portion of the fuel in the charge will be burned between the point where it is charged on the drum and the upper edge of the baille I 0I where it is pivoted at |02. If the charge contains a minimum of moisture, the fuel in it might burn too fast and overheat the grate I8. If the charge contains an excess of moisture, the fuel in the charge would not burn fast enough to bring about the desired sintering. By controlling the rate of air for combustion through the charge in its travel between the point of feed and the upper edge of the baiile IOI, I am enabled to control the rate of sintering and provide for a uniform,

It is also contemplated by my invention, that the motor |05 shall be so geared down as to operate the baille I0| quite Islowly and that the temperature response within the suction chamber between the wall 53 and the baille IIJI will be such that the motor |06 will be stopped by opening of the switch |08 before undesired overtravel is reached in either direction. It will be obvious. however, that limit switches may be employed if desired.

After the charge has passed beyond the upper edge of the side wall 54 of the suction chamber and is on its downward movement on the drum I4, it is engaged by a scraper I I4 and is removed from the drum.

From the foregoing, it will be apparent that I have devised an improved sintering furnace which is continuous and automatic in its operation. is of large capacity, and is one in which the combustion is so controlled that there is no danger of the parts becoming overheated. It will further be seen that I have devised an improved means to control both the rate of feed and the rate of combustion in the furnace.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1. A sintering furnace comprising a hollow iS Controlled by means of a reversing switch |08 16 rotary drum having a gas permeable surface.

means defining a stationary suction chamber within the drum, said chamber having an open top subtending an arc within the upper quadrant of the drum, means to feed a sinterlng charge of ore and fuel onto the surface of the drum to be carried thereby over the suction chamber, means to ignite the fuel in the charge at the beginning of its travel on the drum, suction means connected to the bottom of both endsof the suction chamber to draw air for combustion through the charge, a movable bae extending longitudinally within the suction chamber intermediate its sides for varying the suction through the charge during the initial portion of its travel, a motor operatively connected to the baille for varying its position,

` and temperature responsive means within the chamber for controlling the motor.

2. A sintering furnace comprising a rotary drum having a gas permeable surface for supporting a sintering charge, a stationary suction chamber mounted within the drum and having an open top subtending an arc in the upper quadrant of the drum and having side and end walls cooperating with the surface and ends of the drum to seal off the remainder of the surface of the drum, suction conduits connected to the bottom of both ends of the suction chamber, a baille extending longitudinally within the chamber intermediate the sides thereof and suspended from its upper edge therein, a motor operatively connected to the lower portion of the bale to vary its position in the chamber, and means responsive to temperature within the chamber for controlling the motor.

. GEORGE C. BURGESS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 916,394 Dwight et al. Mar. 23, 1909 1,401,054 Delacourt Dec. 20, 1921 1,471,402 Lloyd Oct. 23, 1923 1,489,938 Hale Apr. 8, 1924 1,880,146 Morison Sept. 27, 1932 1,961,893 Wadman et al June 5, 1934 1,992,704 Lellep Feb. 26, 1935 2,064,495 Queneau Dec. 15, 1936 2,123,593 Vogel-Jorgensen July 12, 1938 2,187,727 Brown Jan. 23, 1940 2,193,698 Rolfsen Mar. 12, 1940 2,244,372 Pomeroy June 3, 1941 2,283,053 Gohre May 12, 1942 2,410,944 Johnson. Nov. 12, 1946