JPH0790130B2 - Filter device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a filter for magnetically filtering a liquid containing multiple magnetic powder particles such as an electric discharge machining liquid.

[Conventional technology and problems]

The magnetic filter magnetizes a rotating filter, belt, mesh, or other magnetic filter element to adsorb and separate the magnetic powder particles in the liquid to be filtered. Various devices have been proposed.

However, in the machining fluid used for electrical discharge machining, the particle size is
Since various powder particles are mixed and distributed over a wide range of sizes from mm order to Å order, it is extremely difficult to separate them efficiently.

In addition, since the amount of processing dust such as magnetic powder particles generated by processing varies depending on the processing conditions and the quality of the processing state, in conventional magnetic filters, the magnetic powder particles are always efficiently and uniformly dispersed from the used processing liquid. It is difficult to separate and remove at the filtration rate.

In view of such a problem, the present invention is capable of efficiently separating magnetic powder particles of large and small particle diameters, and the magnetic powder particles are always efficiently and uniformly irrespective of processing conditions and processing conditions. It is an object of the present invention to provide a filter device which can be separated at a filtration rate and can withstand continuous operation for a long time.

[Means for solving problems]

In order to achieve this object, the filter device of the present invention is provided with a magnetizing coil in a flow path for supplying a used machining liquid to a filter element, an exciting power source for exciting the magnetizing coil in a pulsed manner, and a magnetic powder grain by machining. Is provided with a control device for controlling the excitation pulse by the excitation power source according to the generation amount of.

[Work]

By controlling the width or frequency of the pulse that excites the magnetizing coil according to the amount of magnetic powder particles generated by processing, and changing the strength of the magnetic field, the amount of magnetic powder particles generated varies depending on the processing conditions and processing conditions. Regardless of the above, the generated magnetic powder particles, both small and large, are magnetized uniformly and evenly to the extent that they can be magnetically adsorbed and separated, and the magnetic particles that have been magnetically adsorbed to the filter element are not difficult to remove with a scraper. It is possible to magnetize the magnetic powder particles, and the magnetic powder particles are always efficiently separated at a constant filtration rate. Also, by controlling the pulse such as the width or frequency of the excitation pulse,
The magnetic field is accurately controlled.

〔Example〕

The present invention will be described below with reference to an embodiment of the drawings. FIG. 1 shows an example of water treatment of a working fluid of a wire cut electric discharge machine. A wire electrode 1 is supplied from a reel and runs between the upper and lower guides 2 with a predetermined tension and speed. Reference numeral 3 denotes a workpiece, which is opposed to the wire electrode 1 between the guides 2 for electrical discharge machining. The working fluid is jetted from a pipe 4 from a nozzle that coaxially surrounds the upper and lower guides 2 toward the working portion, and a pulsed power supply (not shown) supplies a pulse current between the wire electrode 1 and the workpiece 3 through the working fluid. Process by repeating electric discharge. The supplied processing liquid flows down while washing away the processing waste generated by electric discharge, is collected in the processing tank 5, and is supplied from the pipe 6 to the filter 7. Reference numeral 8 is a magnetic drum, 9 is a scraper, 10 is a machining waste removal port, and 11 is a cleaning liquid discharge port, which leads to a processing liquid supply layer (not shown) and is supplied and circulated from the processing liquid supply layer to the pipe 4 by a pump. 12 is a rotary motor for the drum 8 and 13 is a filter 7 for processing fluid collected in the processing tank 5.
, A magnetizing coil provided in the pipe 6 for supplying a magnetic field, a magnetizing coil 14 for exciting the magnetizing coil 13 in a pulsed manner,
Reference numeral 15 is a drive power source for the motor 12, and 16 is a control device.Since the amount of machining waste generated is determined based on the integration of the machining current and the machining time, each power source 14, 15 is fed by a machining current signal and proportionally integrated. To control the pulse width or frequency of the exciting pulse of the magnetizing coil 13 by the exciting power supply 14 or further change the current peak value and the like.
The drive of the motor 12 by 15 is controlled to change the rotation of the drum 8.

FIG. 2 is a side view of the drum 8 taken along the line AA ′, which is constructed by alternately laminating a plurality of plates 81 (13Cr, FeCrCo, other corrosion-resistant magnetic material, etc.) 81 and a permanent magnet 82 on a shaft 83. 83 motor
It is designed to rotate by 12.

In the above, the processing drainage flowing through the processing gap and flowing down to the processing tank 5 is supplied through the pipe 6 to the rotating filter of the drum formed by the plurality of magnetic blades 81 magnetized by the permanent magnet 82. However, the working liquid supplied to the filter is urged by the acting magnetic field of the magnetizing coil 13 provided in the pipe 6. This acting magnetic field is a magnetizing coil
A magnetic field that changes in a pulsed manner acts by pulse-exciting 13 and the magnetic metal powder particles in the drainage are magnetized by this acting magnetic field and supplied to the filter 7 in a state having residual magnetism. In this manner, the processing wastes to be separated and removed are magnetized to have the residual magnetism and the filtered processing liquid is supplied to the filter 7, whereby the magnetic attraction to the drum 8 becomes easy and the particle size is small. Not only magnetic particles, but also magnetic particles with large particle size can be efficiently adsorbed and separated from magnetic powder particles of various sizes.

The pulse excitation of the magnetizing coil 13 by the excitation power supply 14 increases the amount of magnetic powder such as machining dust generated when the machining speed is increased by a large current, so that the pulse width of the excitation pulse is increased or the frequency is increased. By controlling the pulse, the action magnetic field is strengthened, and a large amount of magnetic powder particles are uniformly and uniformly magnetized by a predetermined magnetizing force to control so as to increase adsorption separation by the magnetic drum 8. The rotational speed of the drum 8 is increased to control the amount of magnetic attraction. In these controls, command output control is performed from the controller 16 by inputting a signal such as a machining current.

The processing waste adsorbed on the drum 8 is scraped off by the scraper 9 and discharged from the discharge port 10, and the clean water from which the processing waste is separated flows out from the discharge port 11 at the bottom of the filter tank and is reused for circulation. . The drum 8 is continuously rotated, the adsorption separation of the machining waste and the scraping of the adsorbed matter are repeated continuously, and the cleaning liquid can be circulated and used, whereby the electric discharge machining can be stably continued.

FIG. 3 shows another embodiment of the filter, in which an electromagnet is used to magnetize the magnetic blade 18 forming the drum.
Reference numeral 18 denotes a magnetic iron core facing each blade 81 laminated at intervals, 19 is its exciting coil, and DC excitation may be used for exciting this coil, but a pulse controlled by the control device 16 in FIG. It is possible to perform pulse excitation by the power source 17 and adjust the excitation pulse width so as to improve the suction separation of the processing waste and the removal efficiency by the scraper 9.

FIG. 4 shows that two or more magnetizing coils for magnetic field processing 131, 132 are provided in multiple stages, and excitation power sources 141, 142 are respectively provided to control the pulse width, frequency, current peak value, etc. of the excitation pulse to perform optimum magnetization processing. It has been improved. When fine powders to large particles are distributed and mixed in the liquid to be filtered over a wide range, this magnetic field treatment causes the fine powders to be adsorbed to each other to increase the particle size, or between the particles of the magnetic material. Non-magnetic particles are sandwiched between the magnets, and a plurality of magnetizing coils are provided along the pipe flow path in multiple stages to control the phase of the magnetizing coils, etc., to uniformly magnetize the various particles mixed in the liquid. It is possible to increase the efficiency of adsorption / separation and filtration.

In the above, the example in which the plate 81 of the drum 8 is magnetized by the permanent magnet or the electromagnet to perform the filter treatment of the adsorption separation of the magnetic particles is described. However, the blade 81 can be used without magnetizing, and the magnetic powder by the magnetizing coils 13, 131, 132 can be used. It is possible to supply the material in a state having a residual magnetism by sufficiently performing the magnetization processing of the above, and magnetically attract this to the blade 81 to perform the separation processing. In this case, since the blade is not magnetized, the effect of facilitating the peeling removal by the scraper 9 can be obtained.

If a PWM modulation circuit is used for the pulse excitation power supply of the magnetizing coils 12, 131, 132 for magnetic field processing, pulse width control can be easily performed, and optimal control can be performed according to the state of the liquid to be filtered, and magnetizing processing can be performed favorably. Magnetization frequency is 1KHz, Ip 5A
Use it to some extent. Since the amount of machining chips generated depending on the electrical discharge machining conditions increases or decreases, if the PWM modulation control is performed by the switching signal of machining conditions, the detection signal of machining current, etc., the magnetizing process can be performed according to the amount of machining chips produced. It is possible to maintain a constant filtration rate and continue stable electric discharge machining. The filtration rate is usually about 98% or more, and the filtration separation can be performed.

Also, the rotation speed of the drum 8 by the motor 12 may be controlled according to the amount of machining waste produced, and may be changed and controlled in the range of usually 0.1 to 10 rpm.

The filter element is not limited to the disc-shaped element that forms the drum, and a belt-shaped element or the like can be used as desired. Further, the filter device of the present invention is effective as a filter device for a machining liquid used for various machine tools, in addition to a machining liquid for electric discharge machining, which contains magnetic powder particles.

〔The invention's effect〕

As described above, according to the present invention, the magnetizing coil is provided in the flow path for supplying the used machining liquid to the filter element, the magnetizing coil is excited in a pulsed manner, and the exciting pulse is magnetic powder particles produced by machining. By changing and controlling according to the production amount of, it is possible to efficiently separate the magnetic powder particles of large and small sizes contained in the used processing liquid, and to make the processing conditions and processing conditions different. In spite of this, the magnetic powder particles can always be efficiently and efficiently separated at a constant filtration rate, and a stable desired filtration treatment can be performed to continuously operate for a long time.

If the filter element is made of a magnetic material that is not magnetized, the magnetic powder particles in the used machining fluid will be magnetically attracted to the filter element due to the residual magnetism resulting from the magnetization treatment by the pulsed magnetic field. The magnetic powder particles adsorbed and separated on the element can be easily removed by a scraper.

When the filter element is made of a magnetized magnetic material, the magnetic powder particles in the used machining fluid are magnetized by the pulsed magnetic field, so that the magnetic powder particles are not magnetized to the filter element. The adsorption separation is performed extremely efficiently.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a partial sectional view taken along the line AA ′, FIG. 3 is a partial sectional view of another embodiment, and FIG. 4 is another embodiment. It is a block diagram. 6 …… Processing drainage pipe 7 …… Filter 8 …… Drum 9 …… Scraper 81 …… Blade 82 …… Permanent magnet 80 …… Axis 12 …… Rotating motor 13 …… Magnetizing coil 14 …… Excitation power supply 15 …… Drive power supply 16 …… Control device

Claims (3)

[Claims] 1. A filter device for separating magnetic powder particles from a used working fluid, wherein a magnetizing coil is provided in a flow path for supplying the used working fluid to a filter element, and the magnetizing coil is excited in a pulsed manner. A filter device comprising a power supply and a control device for controlling an excitation pulse by the excitation power supply according to the amount of magnetic powder particles generated by processing. 2. The filter device according to claim 1, wherein the filter element is made of a magnetic material that is not magnetized. 3. The filter device according to claim 1, wherein the filter element is composed of a magnetized magnetic material.