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Publication numberUS3817697 A
Publication typeGrant
Publication dateJun 18, 1974
Filing dateDec 15, 1972
Priority dateDec 15, 1972
Also published asCA997966A1
Publication numberUS 3817697 A, US 3817697A, US-A-3817697, US3817697 A, US3817697A
InventorsE Parobek
Original AssigneeCombustion Eng
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Rotary kiln for metal chip deoiling
US 3817697 A
Abstract
A rotary kiln in which oil and water can be removed from the metal chips in which a burner having outlets positioned throughout the length of the kiln introduces heat. The fuel to air ratio is adjusted such that no excess air is available in the kiln for combusting the oil coating on the chips. Thus the chips are subject to pyrolization in a reducing atmosphere, with the water and oil being vaporized and removed from the kiln along with the combustion exhaust gases.
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Description  (OCR text may contain errors)

O Unrted States Patent 11 1 1111 3,817,697 Parobek June 18, 1974 ROTARY KILN FOR METAL CHIP 2,836,901 6/1958 Davis 432/72 DEQILING 2,850,273 9/1958 Barnes 432/117 X 3,497,190 2/1970 Moore 432/72 Inventor: Edward George Parobek, Seven 3,606,285 9/1971 Bayer 432/117 Hills, Ohio [73] Assignee: Combustion Engineering, Inc., Primary camby Windsor, Conn Attorney, Agent, or Fzrm-Robert L. Olson [22] Filed: Dec. 15, 1972 [57] ABSTRACT [21] Appl' A rotary kiln in which oil and water can be removed from the metal chips in which a burner having outlets [52] US. Cl 432/105, 266/335, 432/72 Positioned throughout the ength of he kiln intro- 51 161.01. F27b 7/02 duces heat- The fuel to air ratio is adjusted such that [58] Fi ld of S h 432/103, 105 1 15, 117 no excess air is available in the kiln for combusting the 432/1 18, 72; 266/335 oil coating on the chips. Thus the chips are subject to pyrolization in a reducing atmosphere, with the water [56] References Cit d and oil being vaporized and removed from the kiln UNITED STATES P along With the combustion exhaust gases.

1,797,130 3/1931 Coley 432 72 1 Claim, 2 Drawing Figures 1 I l l I I 1 l i l l 1 ROTARY KILN FOR METAL CHIP DEOILING BACKGROUND OF THE INVENTION In metal milling and drilling operations, huge amounts of metal chips and other small metal scraps are produced. Since most of the machining uses oil and/or water as lubricants, the metal chips contain a coating of oil and water which must be removed prior to reprocessing them. One method of accomplishing this in the past has been to heat the chips in a retort, using indirect heat, on the outside of the retor. Because of the low efficiency in this type of drying operation, it is expensive. Another method used is to burn the oil coating on the metal chips in a furnace. This causes undesirable oxidation of the metal chips, and also is subject to the hazard of explosion. In accordance with the present invention, a rotary kiln is provided for removing oil and water coatings from metal chips in an efficient manner without the hazard of furnace explosion or oxidation of the metal chips being treated.

SUMMARY OF THE INVENTION The rotary kiln of the invention utilizes a burner having outlets extending throughout the length of the housing. The rotating housing has internal longitudinal ribs or vanes for causing the metal chips to cascade or tumble within the housing, thus providing good exposure of all surfaces of the chips to the drying medium. The airfuel ratio of the burner is adjusted so no excess air is introduced into the furnace such that the chips are pyrolized in a reducing atmosphere. The water and oil is vaporized, and carried off with the combustion exhaust gases.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a cross sectional side view of a metal chip deoiler furnace or kiln constructed in accordance to the invention; and

FIG. 2 is a sectional view taken on lines 22 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 numeral denotes the rotary kiln or furnace in its entirety. The kiln consists of a substantially horizontal cylindrical housing 11. The housing 1 l is tilted slightly downwardly from its inlet end to the discharge end, so that as it rotates the metal chips 12 are progressively moved through the housing. Metal chips or scrap 12, coated with water and oil, is introduced to the furnace 11 from hopper 14 by means of a screw feeder 16. A rotary air lock 15 located in the bottom of the hooper 14 prevents undesirable air from entering the furnace along with the metal chips, so that the furnace can be maintained in an inert or reducing atmosphere.

Housing 11 is mounted on trunnion rolls 18, which rolls are driven by motor to cause rotation of the housing 1 I. Bellows 22 forms a seal between the rotating housing 11 and the stationary structure 21, while permitting thermal growth of the housing when it is fired. A spring biased annular seal 24 prevents entrance of air at the discharge end of the housing 1 l. The chips, after having the water and oil evaporated therefrom in furnace 11, are discharged through opening 26. Rotary air lock 28 prevents entrance of air to the furnace through the discharge opening.

Heat is provided in the furnace 11 by means of tubular burner 30, which contains openings 32 along its entire length for directing flame at the metal chips throughout the length of the furnace. Thus all of the metal chips contained in the kiln or furnace are continuously exposed to radiant heat throughout the length of the furnace. Burner 30 is supplied with gaseous fuel and air through supply lines 34 and 36, respectively. The ratio of fuel to air is maintained such that no excess air enters the furnace 11 through the burner 30. Thus no oxygen will be present in the furnace to support combustion of the oil coating the metal chips. Thus the oil and water is volatilized or vaporized, and carried out of the furnace along with the combustion exhaust gases through duct 42.

The amount of fuel and air supplied to burner 30 is controlled by valves 38 and 40, respectively. These valves are automatically adjusted by a signal from tem perature sensing device 44 located in the furnace. A temperature of approximately 800F to 1000F is maintained in the furnace, so that all of the water and oil is vaporized, without causing overheating damage to the metal chips.

The volatized combustibles coming from the evaporated oil is combusted by an afterburner 46, located in duct 42. This burner is supplied with an excess of air, to insure combustion of all of the vaporized oil carried by the furnace exhaust gases.

As best seen in FIG. 2, housing 11 has a plurality of longitudinal ribs or vanes 48 attached to its inner wall surface. These ribs 48 extend the entire length of the furnace, and provide a tumbling action for the metal chips as the housing rotates. Thus the flame 50 impinges directly on the shower of cascading metal chips, insuring that all of the surfaces of all chips are exposed to the drying effect of the flame 50. As shown in FIG. 2, the burner openings 32 are located off center to the vertical, to effectively direct the flame 50 at the greatest accumulation of cascading or tumbling chips.

From the above, it can be seen that a highly efficient furnace has been provided for removing the water and oil coatings from metal chips. Since the furnace atmosphere is inert, there is no possibility of explosion. Af terbumer 46 combusts the vaporized combustibles carried by the exhaust gases leaving the furnace. If desired, the duct 42 can also contain a wet scrubber for removing pollutants from the exhaust gases prior to their being discharged to the atmosphere.

What is claimed is:

l. A furnace for removing oil and water from scrap metal including a substantially horizontally cylindrical housing, said housing having an inlet end and a discharge end, means for rotating the housing, said housing being angled slightly downwardly from the inlet end to the discharge end, means for introducing scrap metal to the housing at the inlet end, means for removing scrap metal from the housing at the discharge end, exhaust duct means through which the gases escape from the housing, afterburner means located in the duct means for combusting the combustible volatiles driven off from the scrap metal, a plurality of longitudinal vanes secured to the walls of the housing for causing tumbling of the scrap metal as the housing rotates, burner means positioned within the housing having outlets positioned longitudinally along the entire length of 3 4 the housing, the outlets of the burner means being positrolling the supply of fuel and air to the burner means tioned at an angle to the vertical, and are offset from in such a ratio that no excess air is supplied to the hous the central axis of the housing, such that the flames ising, thereby exposing the scrap metal to pyrolysis in a suing therefrom impinge directly on the greatest accureducing atmosphere.

mulation of tumbling scrap metal, and means for con- 5

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1797130 *Feb 7, 1929Mar 17, 1931Edwin Coley HenryReduction of ores, oxides, and the like
US2836901 *May 26, 1954Jun 3, 1958Link Belt CoMethod for drying metal scrap
US2850273 *Sep 13, 1955Sep 2, 1958Chester F BarnesRotary kiln type metallurgical furnace
US3497190 *Apr 15, 1968Feb 24, 1970James E MooreSystem for hot de-oiling and hot briquetting
US3606285 *Oct 20, 1969Sep 20, 1971Holcroft & CoBarrel-type batch gas carburizing furnace
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4133635 *Feb 7, 1977Jan 9, 1979Combustion Engineering, Inc.Method and apparatus for drying and preheating small metallic particles
US4264060 *Feb 25, 1977Apr 28, 1981Automated Production Systems CorporationApparatus for treating metallic scrap in the recovery of metal therefrom
US4462793 *Aug 2, 1982Jul 31, 1984Kawasaki Jukogyo Kabushiki KaishaRotary kiln and method of using such a kiln
US4504149 *Apr 14, 1980Mar 12, 1985Mendenhall Robert LamarClosed end drum asphaltic concrete recycle apparatus and method
US4522498 *Apr 14, 1980Jun 11, 1985Mendenhall Robert LamarAsphaltic concrete recycle apparatus and method
US4639216 *Mar 13, 1986Jan 27, 1987Schnupp's Grain Roasting, Inc.Grain roasting machine and method
US4683664 *Nov 13, 1984Aug 4, 1987Giovanni CodenottiApparatus for drying metal turnings or scrap
US5226774 *Nov 4, 1991Jul 13, 1993Cadence Chemical Resources, Inc.Device for charging combustible solids to rotary kilns
US5295821 *Jul 6, 1992Mar 22, 1994Daukss Karlis NFoundry sand thermal reclamation system and method
US5619936 *Oct 6, 1994Apr 15, 1997Kleen Soil Technologies, L.C.Thermal desorption unit and processes
US7181864 *Mar 31, 2006Feb 27, 2007Honda Motor Co., Ltd.Dehydration of body hem flanges
US7976611Apr 25, 2006Jul 12, 2011Currenta Gmbh & Co. OhgContinuous process and apparatus for recovering metal from metal and organic waste, by combustion of organic constituent of waste in rotary tube furnace
DE3014686A1 *Apr 16, 1980Nov 6, 1980Automated Prod SystVerfahren zur dekontaminierung von kontaminiertem metallschrott
EP0070819A1 *Jul 15, 1982Jan 26, 1983Boliden AktiebolagA method for working-up metal-containing waste products
WO2006119861A1Apr 25, 2006Nov 16, 2006Bayer Industry Services Gmbh &Method for recovering metals from waste and other materials comprising organic components
Classifications
U.S. Classification432/105, 266/249, 266/901, 432/72
International ClassificationF23G5/18, C23G5/00, C22B1/00, F27B7/10
Cooperative ClassificationF27B7/10, C23G5/00, C22B1/005, Y10S266/901, F23G5/18
European ClassificationC22B1/00D, F23G5/18, C23G5/00, F27B7/10