US2971751A

US2971751A - Cooling apparatus

Info

Publication number: US2971751A
Application number: US714583A
Authority: US
Inventors: Andersen Axel Brix
Original assignee: FLSmidth and Co AS
Current assignee: FLSmidth and Co AS
Priority date: 1958-02-11
Filing date: 1958-02-11
Publication date: 1961-02-14
Anticipated expiration: 1978-02-14

Description

Feb. 14, 1961 ANDERSEN 2,971,751

COOLING APPARATUS Filed Feb. 11, 1958 3 Sheets-Sheet 1 FIG. I

INV NTOR.

BY $6 wad Feb. 14, 1961 A. B. ANDERSEN 2,971,751

COOLING APPARATUS Filed Feb. 11, 1958 3 Sheets-Sheet 2 Feb. 14, 1961 A. B. ANDERSEN 2,971,

COOLING APPARATUS Filed Feb. 11, 1958 :5 Sheets-Sheet 5 FIG. 5

ATTORNEYS United States Patent COOLING APPARATUS Axel Brix Andersen, Larchmont, N.Y., assignor, by mesne assignments, to F. L. Smidth & 10., New York, N.Y., a corporation of Delaware Filed Feb. 11, 1958, Set. No. 714,583

6 Claims. (Cl. 263-32) This invention relates to combined rotary kilns and coolers of the type in which the hot burned product issuing from the kiln passes through cooling cylinders mounted on the kiln to rotate therewith and is cooled by air traveling through the cylinders and into the kiln. More particularly, the invention is concerned with a novel rotary kiln with cooling cylinders, in which the hot kiln product is cooled out of contact with atmospheric air, so that the kilnis especially adapted for the reduction of ores, which would be re-oxidized if exposed. to the atmosphere before being cooled to a reasonably low temperature. in the new combined kiln and cooler, the material may be cooled wholly by loss of heat hrough the cylinder walls, in which event there is no gaseous flow through the cylinders, although, if desired, a neutral or reducing atmosphere may be maintained in the cylinders. In an alternative arrangement, an inert combustible gas is passed through the cylinders to cool the material and the pro-heated gas then enters the kiln to be burned therein.

For a better understanding of the invention,.reference' may be had to the accompanying-drawing, in -which Fig. 1 is a view, partly in side elevationand partly'in section, of the discharge end of a combined rotary kiln and cooler embodying the invention;

Fig. 2 is a sectional view on an enlarged scale of a seal usedin the apparatus of Fig. 1;

Fig. 3 is a sectional viewon the line3-3 of Fig. 1;

Fig. dis a sectional view of another seal employedin the apparatus;'and

Fig. 5 is a view similar to Fig. 1 of a modifiedcombined rotary kiln and cooler of the invention.

The apparatus shownin Fig. 1 comprises a rotary kiln',

the lower end of the shell of which is shown at 1%. The lilnisof-the usual cylindrical form' provided with a refractory lining 19a and mounted for rotation at a low angle-to the'horizontal. The material to be burned and the combustible mixture are introduced. into the upper endof the kiln and the material and the gases of corni-- bustion-travelconcurrently through the kiln. The lower end ofthe kiln is provided with a closure 11 having a central opening from which an outlet duct 12 for gases exteudsaxially-of the kiln. The duct is provided with a lining 12a and is formed in-two

sections

12b, 12c connected-by an expansion joint 13 of conventional construction. The duct is supported aboutmidway of its length by a plate14 closing the end of a cylindrical extension 15 mounted on thelower end of the kiln.

The kiln is provided with a plurality of peripheral, radial discharge ports '16 through'itslining and shell wall adjacent-the closure 11, the ports being arranged in a circumferential series. A discharge spout 17 is mounted on thekiln to extend outwardly from each discharge port and the spout has aflangeat its outer end. A plurality'of cooling cylinders 18-lying parallel to the axis of the kiln are arranged in a-circumferential series about the kiln and its extension 15 and the cylindersare supported in part byclampslflsecuredto arms 20 attached to plate 14 faces of the cylinders with water.

' the lower end of the kiln.

and extending radially therefrom. Each cylinder has an inlet opening at its upper end, from which a short neck 21 extends outwardly to be connected by a flange to the flange on a spout 17. A plurality of longitudinally extending lifters 22 are mounted on the inner surface of each cylinder and the cylinders are also provided with internal dam rings 23. At its lower end, each cylinder is provided with an outlet opening surrounded by a spout 24 connected by a radially-extending pipe 25 to a neck 26 surrounding an opening in the periphery 27 of a casing 28 surrounding theoutlet duct 12.

The casing 28 includes a wall 29 extending radially relative to duct 12 and secured to the outer surface thereof and an opposed similar wall 30 having a central opening. A frusto-conical deflector 31 is mounted in the casing 28 with its large end lying against and secured to the inner face of wall 29 and a lifter 32 extends betweenthe peripheral wall 27 of the casing 28 and the surface of the deflector at one side of each of the openings through wall 27. The deflector extends through the central opening through wall 30 and its small end is secured to the outer surface of the outlet duct. A second frusto-conical deflector 33 is mounted outside casing 28 with its small end lying within and secured to the edge of the opening through wall 36. The large end of deflector 33 lies within a stationary casing 34, which encircles the duct 12.

The joint between the stationary casing 34 and casing 28, which rotates with the kiln, is sealed by a labyrinth seal, which includes a hollow ring 35 securedto casing 34 and having a plurality of concentric ribs 36 on one radial face, which enter corresponding grooves in a'plate 37 secured to the wall 30 of casing 23. The plate 37 carries parts of a gland packing, generally designated 38, which prevents escape of gas through the joint. If desired, liquid may be circulated through the hollow ring 35 to maintain it at a desired temperature.

The casing 34 as an outlet opening with a neck 39, from which a discharge pipe .0 leads. The deflector 33 projects into casing 34, so that the large end of the deflector lies above the outlet opening. The pipe 40 extends to any desired point and may lead to a closed conveyor.

A stationary gas outlet housing 41 is mounted beyond casing 34 and the section 120 of duct 12 projects through the casing and is-sealed to the housing and to the stationarycasing 34 by a labyrinth'seal 42 (Fig. 4), which is similar to the seal employed between casin s 28 and 34. The housing 41 has an opening at its top surrounded by aflanged neck 43, which is connected by a pipe 44 to a stack or the intake of a fan. At its lower'end, housing 41 has a cleanout opening with a remo able closure 45.

The material discharged'from the kiln through ports 16 and entering the cooling cylinders 18 is cooled by loss of. heat through the wallsof the cylinders and, if desired, the cooling action may be increased by spraying the sur- For this purpose, a trough 46 is mounted below the group of cylinders, the trough having a bottom outlet 47. A'pair of manifolds 48 are mounted at one end on brackets 49 attached to the wall of the trough and, at the other, on standards' i9 extending upward through the trough outlet 47. The manifolds are connected by pipes 50 having openings through which jets of-water may be directed against the cylinders as they travel through the trough.

In the operation of the apparatus described, the material to be burned and the combustible mixture are introduced into the kiln at the upper end and the material and the gases of combustion travel concurrently toward The material leaves the kiln through the discharge ports and enters and travels the lengthwise of the cylinders as the kiln rotates, while the hot gases escape through the outlet-duct into the housing 41 and thence to the stack or fan. The material is cooled in its travel through the cylinders 18 and, when it reaches the lower ends of the cylinders, the material passes through the connections to the casing 28. The material entering the casing is deflected by the

deflectors

31, 33, so that it enters the stationary casing 34, from which it escapes through the outlet 39 and pipe 40.

During the cooling of the material in the cylinders 18, the material is in a substantially inert atmosphere, since there is nosignificant flow of air through the cooling cylinders and into the kiln, as in the prior combined kilns and coolers. Accordingly, the material being cooled is not subjected to any substantial re-oxidation. If greater protection against re-oxidation is desired, an inert gas may be introduced into the stationary casing 34 to flow therefrom into the cooling cylinders. When an inert gas is so employed, it is desirable to prevent its escape through the outlet of casing 34 and, for this purpose, the outlet may be provided with a conventional material trap or like device. Ordinarily, the water spray will cool the material sufficiently during its passage through cylinders 18 to prevent re-oxidation upon discharge from the cylinders, but, if an increased cooling effect is desired, the cylinders may be enclosed within a hood, through which air may be drawn by an exhaust fan.

In the modified combined kiln and cooler shown in Fig. 5, the material to be burned is fed into the upper end of the kiln and the fuel-air mixture is introduced into the lower end through the usual burner pipe. As a result, the material and the gases of combustion travel through the kiln in opposite directions.

The lower end of the modified kiln illustrated is provided with a conical end section 51 starting just beyond the row of discharge ports 16' and lined with refractory material. A duct 52 leads from the small end of'the end section and is closed at its outer end by a conventional stuffing box 53, through which extends a burner pipe 541 The pipe projects through the duct 52 to terminate within the end section 51 and, in accordance with the usual practice, is movable endwise to adjust the position of the flame within the kiln. The stuffing box may be of the ball and socket type, if desired, to permit lateral movement of the burner pipe and, if preferred, the duct 52 may be omitted and the stufling box may be mounted directly on the small end of the end section 51. A cylindrical extension attached to the lower end of the kiln encloses the end section 51 and the lower end of the extension is closed by a plate 14'.

A discharge spout 17' extends outwardly from each port 16' and has a flange at its outer end. Cooling cylinders 18' lying parallel to the axis of the kiln are supported in part by clamp 19' secured to arms 20' attached to plate 14 and each cylinder has an inlet opening with a short neck 21' extending therefrom and provided with a flange secured to the flange on a spout 17. The cylinders 18' are similar to cylinders 18 and provided with internal lifters and darn rings. Also, at its lower end, each cylinder has an outlet opening surrounded by a spout 24' connected by a pipe 25 to a neck 26 surrounding an opening in the periphery 27' of a casing 28 surrounding the duct 52. g

The casing 28 is similar to casing 28 and includes a wall 29' secured to the outer surface of duct 52 and an opposed similar wall 39 having a central opening. A frusto-conical deflector 31 ismounted in casing 28 with its large end secured to wall 29' and a lifter 32 extends between the peripheral wall 27' of the casing 28 and the surface of the deflector at one side of each opening through the wall. The deflector extends through the central opening through wall 31 and its small endis secured to the outer surface of the duct 52. A stationary casing 34' lies beyond casing 28' and contains a deflector similar to the deflector 33 in the Fig. 1 construction. The joint between the casings 28' and 34' is sealed by a labyrinth seal generally designated and similar to the seal between the

casings

28 and 34.

The stationary casing 34' has an outlet opening with a neck 39', from which a discharge pipe 40 leads, and the casing is sealed to the duct 52 and to a part of the stufiing box 53 by a labyrinth seal 42', which is similar to the seal 42. The pipe 40 extends to any desired point and may discharge material into a closed conveyor.

The kiln-cooler combination of Fig. 5 is provided with means for cooling the material traveling through the cylinder and may have the spraying means shown in Figs. 1 and 3 with or without a hood, through which air is drawn by a fan.

In the operation of the modified apparatus, the material to be burned is introduced into the kiln at the upper end and travels down the kiln as the latter is rotated The fuel and all the air required for combustion may be introduced through the burner pipe 54 and the proportions of fuel and air are so controlled that the atmosphere within the kiln is non-oxidizing and, preferably, reducing. Upon arriving at the discharge ports, the material passes through the ports into the cooling cylinders and any material traveling beyond the ports is returned thereto by the conical wall of the end section 51. The material is cooled in cylinders 18' in the same manner as in cylinders 13 and the material is kept from exposure to the atmosphere during cooling, so that substantial re-oxidation of the material is prevented.

Instead of supplying a fuel-air mixture through the burner pipe 54 in the Fig. 5 construction, the fuel used may be a gas which is inert with respect to the material being burned in the kiln and may enter the stationary casing 34' and flow therefrom through the rotating casing 28 and the cylinders 18' into the kiln. The gas assists in cooling the material and the pro-heated gas is then burned in the kiln with the air for combustion supplied through the pipe 54.

In the kiln of Fig. 5, the combustion of the fuel-air mixture is carried on in such manner that the material, which has been burned in the kiln, is exposed to a reducing atmosphere. The combustion gases and those evolved from the material being treated pass toward the inlet of the kiln and can be mixed with air supplied by blowers mounted on the outside of the kiln shell to produce a combustible mixture, which can be burned within the kiln to preheat the material traveling down the kiln to the burning zone. Blowers suitable for the purpose are illustrated and described in the US. patent to Borch, No. 2,785,115, issued March 12, 1957.

I claim:

1. The combination comprising a rotary kiln shell having a closed lower end with a central opening and a plurality of discharge ports through the periphery thereof, the discharge ports being located in a circumferential series adjacent to its lower end, a plurality of cooling cylinders mounted in a circumferential series on the kiln shell and encircling its lower end, the cylinders extending lengthwise of the kiln shell and terminating beyond its lower end, inlet conduits extending in a generally radial direction with respect to said kiln shell and connecting said discharge ports with the upper ends of said cooling cylinders for conducting into the cylinders material leaving the kiln shell through said ports, a casing secured to the lower end of the kiln shell coaxially thereof to rotate therewith, the casing lying inwardly relatively to the cylinders, generally radially-extending outlet connections from said cylinders for conducting cooled material from the cylinders at their lower ends into the rotating casing, a stationary casing adjacent to and receiving cooled material from the rotating casing, a seal between the rotating and stationary casings, and a tube directly connected to the lower end of the kiln shell around the central opening for conducting gases from the kiln shell, the tube extending through the stationary and rotating casings and discharging the gases outside the casings.

2. The combination of claim 1,- in which the tube is rigidly attached to the lower end of the kiln, the rotating casing is mounted on the tube, and the stationary casing surrounds the tube outwardly from the rotating casing.

3. The combination of claim 2, in which the casings are open to each other around the tube and deflector means attached to the rotating casing extends through the opening between the casings into the stationary casing to direct into the latter material entering the rotating casing through the outlet connections.

4. The combination of claim 3, in which the deflector means includes a frusto-conical member lying opposite the inner ends of the outlet connections and a second trusto-conical member surrounding and extending beyond the first member and into the stationary casing, the large ends of the members lying remote from each other.

5. The combination of claim 3, in which the rotating casing has a circumferential wall with openings to which the outlet connections lead, and a lifter extends inward from the trailing side of each opening.

6. The combination of claim 1, which includes a housing beyond the stationary casing having an opening in its wall facing the casing, a top opening in said housing for escape of gases and a cleanout opening in said housing, the stationary casing having an opening in its wall facing the housing, and means for sealing the stationary casing, the housing, andrthe end of the tube around said openings in the walls of the stationary casing and housing.

References Cited in the file of this patent UNITED STATES PATENTS 1,652,168 Fasting Dec. 13, 1927 1,690,048 Bentley Oct. 30, 1928 2,026,441 Shafter et al Dec. 31, 1935