U.S. patent number 3,817,697 [Application Number 05/315,741] was granted by the patent office on 1974-06-18 for rotary kiln for metal chip deoiling.
This patent grant is currently assigned to Combustion Engineering, Inc.. Invention is credited to Edward George Parobek.
United States Patent |
3,817,697 |
Parobek |
June 18, 1974 |
ROTARY KILN FOR METAL CHIP DEOILING
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.
Inventors: |
Parobek; Edward George (Seven
Hills, OH) |
Assignee: |
Combustion Engineering, Inc.
(Windsor, CT)
|
Family
ID: |
23225847 |
Appl.
No.: |
05/315,741 |
Filed: |
December 15, 1972 |
Current U.S.
Class: |
432/105; 266/901;
432/72; 266/249 |
Current CPC
Class: |
C23G
5/00 (20130101); C22B 1/005 (20130101); F27B
7/10 (20130101); F23G 5/18 (20130101); Y02P
10/212 (20151101); Y02P 10/20 (20151101); Y10S
266/901 (20130101) |
Current International
Class: |
C23G
5/00 (20060101); F23G 5/18 (20060101); C22B
1/00 (20060101); F27B 7/10 (20060101); F27B
7/00 (20060101); F23G 5/14 (20060101); F27b
007/02 () |
Field of
Search: |
;432/103,105,115,117,118,72 ;266/335 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Camby; John J.
Attorney, Agent or Firm: Olson; Robert L.
Claims
What is claimed is:
1. 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
the housing, the outlets of the burner means being positioned at an
angle to the vertical, and are offset from the central axis of the
housing, such that the flames issuing therefrom impinge directly on
the greatest accumulation of tumbling scrap metal, and means for
controlling the supply of fuel and air to the burner means in such
a ratio that no excess air is supplied to the housing, thereby
exposing the scrap metal to pyrolysis in a reducing atmosphere.
Description
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 air-fuel 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 2--2 of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, numeral 10 denotes the rotary kiln or furnace
in its entirety. The kiln consists of a substantially horizontal
cylindrical housing 11. The housing 11 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 20 to cause rotation of the housing 11. 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 11. 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 temperature sensing device 44 located in
the furnace. A temperature of approximately 800.degree.F to
1000.degree.F 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. Afterburner 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.
* * * * *