Classifying – separating – and assorting solids – Electrostatic – Attracting and repelling
Reexamination Certificate
2002-05-20
2004-08-10
Walsh, Donald P (Department: 3653)
Classifying, separating, and assorting solids
Electrostatic
Attracting and repelling
Reexamination Certificate
active
06774332
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a composite sorting apparatus that separates a mixture into metal pieces (conductive materials) and plastic pieces (non-conductive materials).
BACKGROUND ART
Sorting apparatuses that sort a mixture into metals as conductive materials and plastics as non-conductive materials using electric force include an electrostatic type and a corona discharge type, as well as a composite type using both the electrostatic type and the corona discharge type.
As shown in
FIG. 9
, this composite sorting apparatus is composed of a specified amount supplying section
53
formed of a hopper
51
and a supply plate
52
, a metal drum electrode
54
having a cylindrically formed surface and rotated in a predetermined direction (shown by arrow a) around a horizontal axis, a linear electrode
55
for corona discharge which is provided obliquely above the drum electrode
54
at a downward rotation side thereof and located opposite the drum electrode
54
at a predetermined distance therefrom, a plate-shaped electrode
56
arranged downstream of the linear electrode
55
and opposite the drum electrode
54
at a predetermined distance therefrom to form an electrostatic field, a power supply device
57
that applies high voltage between the drum electrode
54
and both the linear electrode
55
and the plate-shaped electrode
56
, and a collecting container
58
arranged below the drum electrode
54
to collect sorted materials therein.
With this construction, the drum electrode
54
, rotated in a predetermined direction, is grounded to act as a positive electrode, while the linear electrode
55
is used as a negative electrode, to subject the gas in non-uniform electric fields to corona discharge on the basis of the impact ionization action of electrons, thereby generating negative corona ions. The negative corona ions are applied to the drum electrode
54
, and the plate-shaped electrode
56
is used as a negative electrode to form sorting electrostatic fields between the plate-shaped electrode
56
and the drum electrode
54
. In this state, a mixture of metal pieces as conductive materials and plastic pieces as non-conductive materials is loaded from the hopper
51
onto the drum electrode
54
via the supply plate
52
. Then, the mixture moves toward the downstream side of the drum electrode
54
in a rotating direction thereof as the drum electrode
54
rotates, while negative corona ions from the linear electrode
55
are applied to the metal and plastic pieces. The metal pieces, to which the corona ions have been applied, come into contact with the drum electrode
54
, so that negative charges provided by the corona ions are neutralized by positive charges from the drum electrode
54
. The drum electrode
54
further provides positive charges to the metal pieces. Thus, the metal pieces repel the drum electrode
54
and fall therefrom. On the other hand, the plastic pieces, to which the corona ions have been applied, are attracted to the drum electrode
54
due to negative charges provided by the corona ions.
Furthermore, in sorting electrostatic fields, the metal pieces, having positive charges, are attracted to the plate-shaped electrode
56
as a negative electrode, whereas the plastic pieces, having negative charges, are attracted to the drum electrode
54
due to electrostatic force acting thereon.
Thus, the mixture is separated into metal pieces and plastic pieces, which are then collected in the collecting container
58
located below the drum electrode
54
.
However, with the conventional composite sorting apparatus, the linear electrode
55
that applies corona ions to the mixture of metal pieces and plastic pieces emits only a small amount of corona ions and non-uniformly applies corona ions to the mixture. Accordingly, a sufficient amount of corona ions cannot be applied to the mixture, thereby precluding the mixture from being precisely separated into the metal pieces and the plastic pieces.
DISCLOSURE OF INVENTION
Thus, the present invention solves the above problems, and it is an object thereof to provide a composite sorting apparatus that can precisely separate a mixture into metal pieces and plastic pieces.
To solve the above problems, the present invention provides a composite sorting apparatus comprising a rotationally moving electrode disposed so as to rotationally move in a predetermined direction, a discharge electrode for corona discharge which is provided opposite the rotationally moving electrode at a predetermined distance therefrom, a plate-shaped electrostatic electrode provided downstream of the discharge electrode and located opposite the rotationally moving electrode at a predetermined distance therefrom to form an electrostatic field between the electrostatic electrode and the rotationally moving electrode, wherein high voltage of a polarity opposite to that of the rotationally moving electrode is applied between the rotationally moving electrode and both the discharge electrode and electrostatic electrode, a mixture of metal pieces and plastic pieces is loaded onto the rotationally moving electrode, corona ions are applied to the mixture from the discharge electrode, and the mixture is introduced into said electrostatic field so as to be separated into the metal pieces and the plastic pieces, the apparatus being characterized in that the discharge electrode has a plurality of discharge sections each having a sharp tip, the discharge sections are provided in a cross direction of the rotationally moving electrode at predetermined intervals, and arranged so that an interval X cm (in) between adjacent discharge sections with respect to a distance L
1
in cm (in) from tips of the discharge sections to the rotationally moving electrode meets the following expression (1), the discharge sections are each formed so that an area formed on the rotationally moving electrode and to which corona ions are applied has a diameter three times as large as the distance L
1
in cm (in), and a voltage V
1
(kV) applied between the discharge electrode and the rotationally moving electrode meets the following expression (2):
0<
X/L
1
≦3 (1)
0.5
kV/cm
(1.27
kV/in
)≦
V
1
/L
1
≦10
kV/cm
(25.4
kV/in
) (2).
With respect to the above construction, it has been found that corona ions generated by the discharge electrode having discharge sections each having the sharp tip mostly come from the tip of the discharge section. It has also been found that in a facility environment used for the sorting apparatus, the discharge sections of the discharge electrode each form an ion applied area having a width three times as large as the distance L
1
from the tip of the discharge section and the rotationally moving electrode. Accordingly, by setting the interval X between the adjacent discharge sections equal to a value that meets the expression (1), areas to which corona ions from the discharge sections are applied are located at least in contact with each other. Consequently, corona ions are applied to the entire area of the rotationally moving electrode in its cross direction, to ensure a sufficient corona-ion-applied time required for separation, thereby improving separation precision.
Furthermore, the voltage applied per 1 cm (0.3937 in) in the distance between the discharge electrode and the rotationally moving electrode is between 0.5 kV/cm (1.27 kV/in) and 10 kV/cm (25.4 kV/in), thereby ensuring that a sufficient amount of corona ions are generated and preventing the occurrence of a spark (short circuit), which precludes the generation of corona ions. Thus, an amount of corona ions required for separation can be generated.
Accordingly, a mixture of metal pieces and plastic pieces can be precisely separated into the metal pieces and the plastic pieces.
Further, a second aspect of the present invention is the above construction, characterized in that a plurality of rows each composed of a plurality of discharge sections arranged in the cross direction of the rotationally moving electrode are arranged in a rotat
Daiku Hiroyuki
Hamada Shogo
Inoue Tetsuya
Maehata Hidehiko
Tamakoshi Daisuke
Hitachi Zosen Corporation
Kusner & Jaffe
Rodriguez Joseph
Walsh Donald P
LandOfFree
Composite separator does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Composite separator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Composite separator will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3310805