Specialized metallurgical processes – compositions for use therei – Processes – Electrothermic processes
Reexamination Certificate
1997-04-08
2001-05-22
Andrews, Melvyn (Department: 1742)
Specialized metallurgical processes, compositions for use therei
Processes
Electrothermic processes
C075S403000, C075S638000
Reexamination Certificate
active
06235074
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process of effectively recovering copper having a high purity as a copper resource from a copper wire having an enamel coating thereon and a so-called enameled copper wire, in particular in a wound form and in the form of a so-called “winding.”
2. Description of the Related Art
A motor has been often used as a driving means for domestic appliances and industrial machineries. Recently, environmental protection and resource exhaustion are very interested socially, and technical development related to effective use and recycle of resources has to be rapidly accelerated, in which the motor is also considered.
An arrangement of a motor is schematically shown in a cross-sectional view in
FIG. 1
which is used in the domestic appliances or the industrial machineries. As shown in
FIG. 1
, the motor comprises a stator
1
, a rotor
2
, a shaft
3
of the rotor
2
, a bearing
4
, an end bracket
5
as a motor shell, and a frame
6
. The stator
1
has winding
8
formed by winding an enameled copper wire
7
around a core
10
with a predetermined electrical specification, and the wire
7
has an enamel coating outside which functions as an insulation. Passing an electric current through the winding from the outside generates an electromagnetic force, which rotates the rotor
2
.
The stator
1
is often subjected to a varnish treatment for the purpose of insulation reinforcement and mechanical reinforcement of the winding
8
. In addition, a so-called molded motor is often used in which a stator
1
is embedded in a resin body
9
as shown in FIG.
2
. Such a motor is used as a fan motor for the purpose of small sizing, suppressing noise and improving reliability in for example a room air conditioner. Further, a commutator motor is used in a vacuum cleaner as a driving means. In the commutator motor, a rotor (or an armature) having a commutator also has winding which has been varnish- treated.
With respect to the above motors, disassembling and separation of the winding
8
from the core
10
is not so easy since the winding
8
composed of the enameled copper wire
7
has been bonded together or embedded in the resin mold
9
. Thus, it is difficult to economically recover metals as resources from motors collected as wastes. Therefore, there is no other way rather than to dispose the collected spent motors as metal scraps including contaminants or to bury them as they are as industrial wastes. The winding which is particularly used for the motors is worth re-using since it is made of electrolytic copper of which purity is very high (such as not less than 99.9% by weight) so as to reduce copper losses and improve motor efficiency.
There is a process of separating at least metallic elements of electromagnetic members such as winding, a core, and so on from a resin mold by dipping a rotor including the resin mold in an alkali solution so as to alkaline-decompose the resin mold (see Japanese Patent Kokai Publication No. 8-340661). In this process, the resin mold for the electromagnetic members is merely broken by the alkali decomposition so that metal elements are collected. The process may leave the resin on the metal elements and finally there is no other way to treat the collected metal elements as low quality metal scraps.
BRIEF DESCRIPTION OF THE INVENTION
It is therefore an object of the present invention to provide a process of effectively recovering copper having a high purity from winding composed of an enameled copper wire.
According to the present invention, there is provided a process of recovering copper from winding comprising immersing (or dipping) in an alkali solution the winding which is composed of an enameled copper wire having an insulating coating thereon based on a polyester and/or a polyurethane thereon, then removing alkali which is attaching to (or remaining on) the winding, and then melting the winding using high frequency (induction) heating.
In the present invention, the enameled copper wire is intended to mean a copper wire having a polyester and/or a polyurethane based coating thereon for an electrical insulation. The winding made of such an enameled copper wire is immersed into the alkali solution so that the insulation coating is hydrolyzed and degraded, and then alkali is removed from the winding before the winding is melted using high frequency induction heating (i.e. a high frequency melting step) to recover copper. Usually, the insulation coating has been thermally cured. For an industrial application of the present invention, the enameled copper wire may have a very thin film (having a thickness for example in the range of about 1 to 3 &mgr;m) around its periphery which is made of other resin such as a polyamide, and such a film does not adversely affect the present invention, and thus the effects of the present invention can be obtained without a problem. For example, the enameled copper wire may include a nylon thin film for the improvement of its processing properties.
Since the present invention processes the winding composed of the enameled copper wire having a coating material which is hydrolyzed in the alkali solution, the winding of which coating is degraded with the alkali solution treatment is readily obtained, and preferably the winding of which coating is removed is readily obtained. Since such winding is subjected to the high frequency melting step, an amount of copper is recovered which corresponds to substantially all copper used for the winding and which contains less scrap iron or enamel coating residue. Further, since the high frequency melting step is used in which substantially only the removed winding is selectively heated and melted, copper having a high purity is economically regenerated with a high yield.
REFERENCES:
patent: 222338 (1985-05-01), None
patent: 0 142 139 (1985-05-01), None
patent: 0 749 193 (1996-12-01), None
patent: 766835 (1957-01-01), None
patent: 1046395 (1966-10-01), None
patent: 1351448 (1974-05-01), None
patent: 8-340661 (1996-12-01), None
Murano Katsuhiro
Onishi Hiroshi
Terada Takahiko
Yamagata Yoshikazu
Yamashita Fumitoshi
Andrews Melvyn
Matsushita Electric - Industrial Co., Ltd.
Wenderoth, Lind & Ponack
LandOfFree
Process of recovering copper from winding does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process of recovering copper from winding, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process of recovering copper from winding will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2463093