Liquid purification or separation – Processes – Separating
Reexamination Certificate
1999-05-04
2001-02-06
Popovics, Robert J. (Department: 1723)
Liquid purification or separation
Processes
Separating
C210S784000, C210S791000, C210S394000, C210S402000, C210S407000
Reexamination Certificate
active
06183653
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to an electric discharge machine, such as a wire-cutting machine for processing metals with electric discharges, and, more particularly, to an apparatus and a method for removing sludge attached to a filter element arranged in the circulation path of a process solution for use in the electric discharge machine.
2. Description of the Related Art
The wire-cutting electric discharge machine processes, for example, cuts off a work that is immersed into the process solution within a process bath by melting the work partially with discharges intermittently between the work and a wire electrode. The process solution is required to satisfy conditions, such as a predetermined dielectric strength and a low viscosity, so as to remove sludge easily, and accordingly includes water as a main material in the art. The used process solution contains sludge. This sludge is removed through the filter element arranged in the circulation path of the process solution. A part of the solution further passes through an ion exchange resin in order to increase an insulation resistance and is reused. The sludge becomes an adhesive hydroxide compound after the ion exchange and contains powders with various particle diameters between several &mgr;mm and 1 mm.
A filter element that has a white clay layer formed on a surface of pleated (petal shaped) paper in order to increase a filtering area is employed as the filter for removing sludge container in the process solution in the art (for example, JPA 59-64234).
Such filters for use in the electric discharge machine, however, have a disadvantage of a high manufacture cost and a high maintenance expense. In particular, the amount of sludge contained in the process solution increases with the increased performance due to the recent progress in wire-cutting machines and the miniaturization of a cross-sectional area of the wire. The particle diameter also has a tendency to be further miniaturized down to 5 &mgr;mm or less. Thus, if using the conventional filter, the filter element is clogged after running it continuously for about 20 hours and then is required to substitute a new one. Therefore, there is a disadvantage that the expensive filter extremely increases the processing cost.
SUMMARY OF THE INVENTION
The present invention is made in consideration of such disadvantages and has an object to provide an apparatus for removing sludge from a filter element for use in the electric discharge machine and for effectively removing sludge attached to the used and dried filter element (hereinafter referred to as the filter) so as to reuse the filter, thus cutting the maintenance expense sharply.
Another object of the present invention is to provide an apparatus, for removing sludge from a filter for use in the discharge machine, capable of further improving sludge removal efficiency.
A further object of the present invention is to provide a method, for removing sludge from a filter for use in the electric discharge machine, capable of effectively removing sludge so as to reuse the filter and reduce the maintenance expense.
A first aspect of the present invention is provided with an apparatus for removing sludge, applied to a generally cylindrical filter for use in an electric discharge machine. The filter is adapted to remove sludge in a process solution used in the electric discharge machine. The process solution flows from an inner periphery surface to an outer periphery surface and/or the outer periphery surface to the inner periphery surface of the filter. The apparatus, capable of removing sludge attached on a surface of the filter, comprises a filter support device for holding the filter rotatively with the central axis thereof as the central figure and inclining the central axis by a predetermined angle to the horizontal direction.
The filter support device includes cams for providing rotational driving force and successive impactive force to the filter. The apparatus also comprises a motor for providing rotational driving force to the cam, and sludge storage for receiving the sludge falling from the filter.
The filter support device may include a front plate arranged at a front edge side of the filter; a back plate arranged at a rear edge side of the filter; a drive shaft disposed rotatively between the front and back plates; a plurality of cams mounted on front and rear edge portions of the drive shaft, in which the cams contact with front and rear edge portions of an outer periphery of the filter with a certain frictional force; a rotation transmission mechanism for transmitting rotational force of the motor to the drive shaft; a pair of auxiliary shafts arranged on both sides of the drive shaft between the front and back plates; a plurality of rollers mounted on front and rear edge portions of the auxiliary shafts for supporting rotatively the front and rear edge portions of the outer periphery of the filter; a bearing arranged on a plane of the back plate opposing to the rear edge portion of the filter for holding a rear edge surface of the filter rotatively and up/down movably; and a plurality of legs for supporting the front and back plates and the drive and auxiliary shafts inclined by a predetermined angle to the horizontal direction.
According to the first aspect of the present invention, the filter support device holds the filter rotatively in a state where the central axis of the filter is inclined by a predetermined angle to the horizontal direction, and the cams apply rotational driving force and vibrations in the up/down direction to the filter. The sludge attached on the surface of the filter travels on the outer or inner periphery of the filter from a higher portion to a lower portion due to rotations and up/down vibrations and finally falls into the sludge storage for accommodation. The sludge attached to the used filter can be effectively removed and the filter can be reused with using the apparatus. The present invention can reduce the maintenance expense for processing effectively and may also contribute greatly to reduce the resource accordingly.
A second aspect of the present invention is provided with an apparatus for removing sludge, applied to an entirely cylindrical filter for use in an electric discharge machine. The filter is adapted to remove sludge in a process solution used in the electric discharge machine. The process solution flows from an inner periphery surface to an outer periphery surface and/or the outer periphery surface to the inner periphery surface of the filter. The apparatus, capable of removing sludge attached on a surface of the filter, comprises a filter support device for holding the filter rotatively with the central axis thereof as the central figure and inclining the central axis by a predetermined angle to the horizontal direction. The filter support device includes cams for providing rotational driving force and successive impactive force to the filter. The apparatus also comprises a motor for providing rotational driving force to the cam, a mechanism for inverting an inclined direction of the filter by rotating the filter support device with an axis perpendicular to the central axis of the filter and the central figure in a predetermined cycle, and a sludge storage for receiving the sludge falling from the filter.
According to the second aspect of the present invention, the apparatus further comprises the mechanism for inverting the inclined direction of the filter by rotating the filter support device with the axis perpendicular to the central axis of the filter as the central figure in a predetermined cycle, in addition to the first aspect. Thus, the sludge removal efficiency can be further improved.
A third aspect of the present invention is provided with a method for removing sludge, applied to an entirely cylindrical filter for use in an electric discharge machine. The filter is adapted to remove sludge in a process solution used in the electric discharge machine. The process solution flows from an inner pe
Popovics Robert J.
Webb Zeisenheim Logsdon Orkin & Hanson, P.C.
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