JPH07708A - Oil separator - Google Patents

Abstract

(57) [Abstract] [Purpose] To increase the oil recovery efficiency while keeping the voltage applied between the electrodes low. [Constitution] Container 2 to which a mixed liquid 22 containing oil is supplied
7, a first electrode 29 having a large number of passages 29a penetrating the upper and lower surfaces thereof is arranged, and a large number of labyrinthine passages 32 through which the mixed liquid 22 can pass under the first electrode 29 in a container 27.
A second electrode 32 having a and having a vertical thickness larger than that of the first electrode 29 is arranged, and a voltage is applied between the first electrode 29 and the second electrode 32 by the power supply unit 36.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil separator for separating oil mixed with cutting fluid, cleaning fluid, water, bilge wastewater, etc. from these fluids.

[0002]

2. Description of the Related Art When machining a metal material, a cutting fluid is used to improve the cooling property of a cutting portion, the machinability, the life of a cutting tool, and the like. The cutting fluid is stored in a tank attached to the machine tool, and the used cutting fluid is returned to the tank again after foreign matters are removed by a filter and reused.

In a machine tool, lubricating oil is used for lubrication of various parts, and when the used cutting fluid is returned to the tank, this lubricating oil is mixed in the cutting fluid. Therefore, when the same cutting fluid is repeatedly used for a long period of time, a large amount of oil is mixed in the cutting fluid, which causes a problem of deteriorating the performance of the cutting fluid. Further, when oil is mixed in the cutting fluid, there is a problem that the cutting fluid is decomposed and a bad odor is generated.

In order to deal with this, conventionally, the cutting fluid stored in the tank has been regularly replaced, but the replacement cost and the disposal cost of the cutting fluid become high, and many machine tools are used. It is a big problem in the production factory that has. Therefore, an oil separation device capable of using the same cutting fluid for a long time has been developed.

FIG. 7 shows an example of a conventional oil separation device. In FIG. 7, a cutting fluid 2 used for machining is stored in a tank 1. Cutting fluid 2 in tank 1
The oil floating on the liquid surface is pumped up by the pump 5 together with the cutting fluid 2 through the float-like recovery part 3 and supplied into the container 7 through the oil inlet 8. A voltage is applied to the cutting fluid 2 supplied into the container 7 by the + electrode 9 and the-electrode 12, whereby the oil particles mixed in the cutting fluid 2 are electrostatically aggregated.

Particles of oil that have grown due to electrostatic coagulation are separated from the cutting fluid 2, and the separated oil floats on the surface of the cutting fluid 2 and is discharged from the oil discharge port 10 to the outside of the container 7.
The cutting fluid 2 separated from the oil in the container 7 is discharged from the discharge port 15 to the outside of the container 7 and returned to the tank 1. The cutting fluid 2 returned to the tank 1 is supplied to the machine tool side for machining by a pump (not shown), and the cutting fluid 2 used for the machining is returned to the tank 1 again after the foreign matters are removed. Will be returned.

[0007]

However, the oil separation device shown in FIG. 7 still has a problem to be solved.
The cutting oil 2 mixed with oil is supplied from the tank 1 to the container 7, and the oil molecules are aggregated by electrostatic aggregation by the electrodes 9 and 12, but the aggregated oil is distributed along the electrodes 9 and 12 simply by the difference in specific gravity. There is a problem that the efficiency of oil recovery is poor because it only floats. In order to improve the oil recovery efficiency, the voltage applied between the electrodes 9 and 12 may be increased to enhance the electrostatic agglomeration effect, but since the cutting fluid 2 is water-soluble, there is a problem in terms of measures against electric shock.

As a prior art of an oil separation device, Japanese Patent Laid-Open No. Hei 4-
Japanese Patent Laid-Open No. 59002 is known, but in this case as well, the oil recovery efficiency is poor because the oil recovery is only by electrostatic aggregation. Further, in the oil separation device of the present publication, an AC voltage is applied to the electrodes, so a voltage higher than the DC voltage is required, and there is a similar problem in terms of measures against electric shock.

In view of the above problems, it is an object of the present invention to provide an oil separation device capable of enhancing the oil recovery efficiency while suppressing the voltage applied between the electrodes to a low level.

[0010]

An oil separating apparatus according to the present invention for achieving this object is a container to which a mixed liquid containing oil is supplied from below, and an upper and lower surfaces arranged in the container. A first electrode having a large number of passages therethrough, and a plurality of labyrinthine passages arranged below the first electrode in the container, through which the mixed liquid can pass toward the first electrode. And a second electrode having a thickness larger in the up-down direction than the first electrode, and a power supply section for applying a voltage between the first electrode and the second electrode. .

[0011]

In the oil separation device thus constructed,
The mixed liquid containing oil is supplied into the container from below. Since a voltage is applied between the first electrode and the second electrode, the oil particles in the mixed liquid existing between the first electrode and the second electrode are electrostatically aggregated. And is attracted to the first electrode side by the electrostatic field. Since the second electrode is located below the first electrode, the floating of the oil particles present therebetween is significantly promoted by the levitation force due to the specific gravity and the attraction force due to the electrostatic field. The oil particles sucked toward the first electrode side further float up through the passage of the first electrode and reach the liquid surface.

Part of the mixed liquid supplied into the container also flows into the second electrode having a large number of labyrinthine passages. Second
Since the thickness of the electrode is larger than that of the first electrode in the vertical direction, the mixed solution supplied into the container is mixed in the mixed solution while passing through the labyrinthine passage of the second electrode. The oil molecules (oil particles) coalesce and the size becomes large.

As described above, by passing a part of the mixed liquid through the second electrode, the oil molecules are forcibly combined with each other,
Since the combined oil molecules are attracted to the first electrode side by the electrostatic field, it is possible to remarkably promote the floating of the oil as compared with the conventional device. Therefore, even if the voltage applied between the first electrode and the second electrode is kept low, the oil recovery efficiency can be sufficiently increased.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the oil separator according to the present invention will be described below with reference to the drawings.

First Embodiment FIGS. 1 to 5 show a first embodiment of the present invention.
Especially, it shows the case of being applied to a cutting fluid used for machining. In FIG. 1, reference numeral 21 indicates a tank.
A cutting fluid 22 as a mixed fluid is stored in the tank 21. In the tank 21, an oil recovery unit 23 that floats on the surface of the cutting fluid 22 is arranged. The oil recovery unit 23 is provided with a large number of holes 24 for sucking the oil floating on the liquid surface.

A pump 25 is attached to the upper surface of the tank 21. The pump 25 is a flexible hose 26.
It is connected to the oil recovery unit 23 via. A container 27 is disposed on the upper surface of the tank 21 adjacent to the pump 25. The container 27 is made of metal and is grounded to the ground. The container 27 is open upward.

An inlet 28 is provided on the side surface of the container 27. The inlet 28 is connected to the discharge side of the pump 25. The inlet 28 is located between a first electrode 29 and a second electrode 32, which will be described later. The cutting fluid 22 in the tank 21 pumped up by the pump 25 is
8 is supplied into the container 27. An insulator 31 is fixed to the inner surface of the upper portion of the container 27. The insulator 31 holds the first electrode 29 made of a conductor.

The first electrode 29 is composed of a plate-shaped conductive member extending in the horizontal direction. The first electrode 29 has a large number of passages 29a penetrating the upper and lower surfaces. Container 2
An insulator 33 is fixed to the inner surface of the lower portion of 7. The second electrode 32 made of a conductor is held by the insulator 33. The second electrode 32 is arranged below the first electrode 29 and has a large number of labyrinthine passages 32a through which the cutting fluid 22 mixed with the oil particles 22a can pass. The second electrode 32 has a thickness T in the vertical direction significantly larger than that of the first electrode 29.

The second electrode 32 is preferably made of a porous material such as sponge, as shown in FIG. The second electrode 32 made of a porous body is made of, for example, a nickel alloy. The second electrode 32 can be used as long as it is a conductor having a large number (numerous) of labyrinthine passages through which the cutting fluid 22 can pass, and is, for example, a metal scrubber-like one used at home. It may be a stack of many wire meshes.

An oil discharge port 30 is provided in a side surface portion of the container 27 located above the first electrode 29.
The oil discharge port 30 is connected to an oil recovery container such as a drum can (not shown). A discharge passage 34 is formed on the other side surface of the container 27. The discharge passage 34 extends upward along the side surface of the container 27. In the side surface portion of the container 27 located below the first electrode 29, the discharge passage 34 is provided.
An outflow port 40 that communicates with the inside of the container 27 is formed. At the upper part of the discharge passage 34, the cutting fluid 2 from which the oil has been removed
A discharge port 35 for discharging 2 is provided. Oil outlet 3
0 is arranged at a position slightly higher than the discharge port 35 of the cutting fluid 22.

A voltage is applied between the first electrode 29 and the second electrode 32 by the power supply section 36. The power supply unit 36 has a function of outputting a DC voltage. The first electrode 29 is connected to the positive pole of the power supply unit 36,
The second electrode 32 is connected to the negative electrode of the power supply unit 36. In this embodiment, the first electrode 29 and the second electrode 3
A voltage as low as 3.02 to 3.33 V is applied between the first and second terminals. In this state, a current of 9 mA or less flows between the first electrode 29 and the second electrode 32 so that hydrogen gas due to electrolysis is not generated.

Next, the operation of the first embodiment will be described. When the metal material is cut by the machine tool, the cutting fluid 22 is supplied to the cut portion. The used cutting fluid 22 is returned to the tank 21 after dropping to the bottom of the machine tool. Cutting fluid 22 returned to the tank 21
A small amount of lubricating oil on the machine tool side will be mixed in.

The oil mixed in the cutting fluid 22 returned to the tank 21 floats on the liquid surface due to the difference in specific gravity. The oil floating on the liquid surface is sucked by the oil recovery unit 23 together with the cutting fluid 22 and supplied into the container 27 via the pump 25.
A part of the cutting fluid 22 supplied into the container 27 also flows into the second electrode 32 having a large number of labyrinthine passages 32a.

Since the DC voltage is applied between the first electrode 29 and the second electrode 32 when the cutting fluid 22 is supplied into the container 27, electrostatic aggregation of the oil molecules 22a is prevented. As shown in FIG. 3 and FIG. 4, the oil molecules 22a in the cutting fluid 22 are moved by the electrostatic force to cause the first electrode 2 to move.
It is sucked to the 9 side. Therefore, the oil molecules 22a in the cutting fluid 22 flowing into the labyrinthine passage 32a of the second electrode 32 are
Will also be attracted to the first electrode 29 side.

The second electrode 32 is composed of a porous body made of a nickel alloy, and the labyrinthine passage 32a of the second electrode 32 is extremely narrow, so that the second electrode 32 is formed.
In the cutting fluid 22 that has flowed into the, the oil molecules are united with each other while flowing through the labyrinthine passage 32a, and the oil molecules 22a become large. Therefore, the oil molecules 22a that have escaped from the second electrode 32 are significantly larger than the oil molecules 22a in the cutting fluid 22 that is supplied into the container 27. The effect of the coalescence of the oil molecules 22a is better when the thickness T of the second electrode 32 made of a porous material is larger.

Oil molecule 22a escaped from the second electrode 32
Is charged with a negative charge, the oil molecules are repelled by the second electrode 32 having the same potential, as shown in FIG. Since the first electrode 29, which is a positive electrode, is located above the second electrode 32, the oil molecules 22a repelled by the second electrode 32 move toward the first electrode 29 side due to electrostatic force. Sucked. Since the direction in which the oil molecules 22a are sucked coincides with the direction in which the oil molecules 22a float due to the difference in specific gravity, the floating of the oil molecules 22a is significantly promoted.

Since the floating of the oil molecules 22a in the cutting fluid 22 is promoted, the concentration of the oil becomes high in the vicinity of the first electrode 29, and the oil passes through the passage 29a of the first electrode 29 to reach the first position. Above the electrode 29 of. The oil floating above the first electrode 29 is guided to a container such as a drum can (not shown) via the oil discharge port 35.

The cutting fluid 22 in which the oil molecules 22a are significantly reduced settles due to the difference in specific gravity and flows out to the lower part of the container 27 via the second electrode 32. The cutting fluid 22 that has flowed to the lower portion of the container 27 flows upward from the outflow port 40 through the discharge passage 34 and is discharged from the discharge port 35. The cutting fluid 22 discharged from the discharge port 35 is returned to the inside of the tank 21 via a pipe line (not shown).

Table 1 shows the first electrode 29 and the second electrode 32.
The relationship between the voltage applied between the electrodes and the current flowing between the electrodes is shown. The series resistance value in Table 1 indicates a value between the first electrode 29 and the second electrode 32.

[0030]

[Table 1]

As shown in Table 1, the applied current value is 9.82.
When it exceeds mA, hydrogen gas is generated on the side of the first electrode 29 due to electrolysis of the cutting fluid 22. In this embodiment, generation of hydrogen gas is prevented by suppressing the energizing current to 9 mA or less. Also, the applied voltage is 3.33.
It can be suppressed to V or less, and there is no fear of electric shock to the operator.

Table 2 shows the results of measuring the degree of oil recovery from the cutting fluid 22. A in Table 2 indicates the oil content on the outlet side of the pump 25, and B indicates the oil content on the discharge port 35 when a predetermined voltage is applied between the electrodes. The processing capacity of the cutting fluid 22 is 20 liters /
It was set to min.

[0033]

[Table 2]

Thus, in this embodiment, the second electrode 32
The oil molecules 22a in the cutting fluid 22 are united by the oil particles 22a and passed through the second electrode 32 by the electrostatic force.
Therefore, it is possible to remarkably improve the oil recovery efficiency. Therefore, it is possible to improve the oil recovery efficiency while suppressing the voltage applied between the electrodes 29 and 32 to be low, and sufficiently secure the safety against electric shock.

In this embodiment, the first electrode 2
Although a DC voltage is applied between 9 and the second electrode 32, the oil recovery efficiency can be similarly increased even when an AC voltage is applied. Therefore, when the AC voltage is applied, the applied voltage can be reduced by the amount that the oil recovery efficiency is increased, and the safety against electric shock can be improved.

Second Embodiment FIG. 6 shows a second embodiment of the present invention. The second embodiment is different from the first embodiment only in the presence or absence of the bubble generating means, and the other parts are the same as those in the first embodiment. Therefore, the same reference numerals as those in the second embodiment are attached to the corresponding parts. The description of the corresponding parts will be omitted, and only different parts will be described.

A bubble generating means 51 is arranged below the container 27 to which the cutting fluid 22 is supplied from the tank 21. The bubble generating means 51 includes a porous body 52, a check valve 53, and a compressor 54. The porous body 52 is a container 27.
Is disposed between the bottom of the second electrode 32 and the second electrode 32. The check valve 53 and the compressor 54 are arranged outside the container 27.

The porous body 52 has many holes and is formed in a cylindrical shape. One end of the porous body 52 is closed, and the other end is connected to the compressor 54 via a check valve 53. The check valve 53 has a function of preventing the cutting fluid 22 from flowing back to the compressor 54 side.
The compressed air discharged from the compressor 54 is supplied to the check valve 5
The bubbles are supplied to the porous body 52 via 3 and countless bubbles are jetted into the cutting oil 22 from the surface of the porous body 52.

Next, the operation of the second embodiment will be described. The air compressed by the compressor 54 is supplied to the porous body 52 via the check valve 53, and innumerable bubbles are generated in the cutting fluid 22. Since the bubbles have a property of being easily adapted to the viscosity of oil, the bubbles float while adsorbing unseparated oil molecules in the cutting fluid 22. Therefore, the cutting fluid 22 flowing out to the bottom of the container 27
The floating of the oil molecules inside to the second electrode 32 side is promoted.

As described above, by forcibly levitating the cutting fluid 22 flowing out to the lower portion of the container 27 by the bubbles, it is possible to increase the inflow amount of the oil component to the second electrode 22. Therefore, as compared with the case where the cutting fluid 22 simply flows out to the lower portion of the container 27, the oil recovery capability can be improved.

[0041]

According to the present invention, the following effects can be obtained.

(1) A first electrode is arranged above and a second electrode is arranged below in a container into which a mixed liquid containing oil is supplied, and between the first electrode and the second electrode. Since the voltage is applied by the power supply unit, the oil particles existing between the electrodes can be electrostatically aggregated, and the oil particles can be attracted in the oil floating direction by the electrostatic force.

(2) Since the second electrode is made thicker than the thickness of the first electrode, when the oil particles pass through the labyrinthine passage of the second electrode, the coalescence of the oil particles is made. Can be performed, and the size of the oil particles that have passed through the second electrode can be increased.

(3) As described above, since the oil particles increased in size by the coalescence can be attracted upward by the electrostatic force, it becomes possible to remarkably promote the floating of the oil to the first electrode side. The oil recovery efficiency can be significantly increased compared to the conventional case.

(4) Since the oil recovery efficiency can be greatly increased, the voltage applied between the first electrode and the second electrode can be suppressed to a low level, and the safety against electric shock can be improved. You can

(5) When the mixed liquid is applied to a cutting liquid used for machining, for example, the same cutting liquid can be used for a long period of time, and the replacement cost and the processing cost of the cutting liquid can be reduced. This is a significant advantage in a production plant that owns many machine tools.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an oil separation device according to a first embodiment of the present invention.

2 is a perspective view of a second electrode in the device of FIG. 1. FIG.

FIG. 3 is a cross-sectional view showing a charged state of oil molecules when a voltage is applied between electrodes arranged in a container of the apparatus of FIG.

FIG. 4 is an enlarged cross-sectional view of FIG.

5 is an enlarged cross-sectional view showing a floating state of oil molecules on the second electrode of FIG.

FIG. 6 is a schematic configuration diagram of an oil separation device according to a second embodiment of the present invention.

FIG. 7 is a cross-sectional view showing an example of a conventional oil separation device.

[Explanation of symbols]

 21 Tank 22 Cutting Fluid as Mixed Liquid 22a Oil Molecule 27 Container 29 First Electrode 32 Second Electrode 32a Labyrinthine Passage 36 Power Supply 51 Air Bubble Generating Means

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masahiro Yamashita 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd. Umi Kogyo Building 306 Liquid Consand Co., Ltd. Company (72) Inventor Mikio Umemura 687 Iino, Fujioka-cho, Nishikamo-gun, Aichi Prefecture

Claims (1)

[Claims] 1. A container to which a mixed liquid containing oil is supplied from below, a first electrode arranged in the container and having a plurality of passages penetrating upper and lower surfaces, and the first electrode in the container. Second electrode that is arranged below the first electrode, has a large number of labyrinthine passages through which the mixed liquid can pass toward the first electrode, and has a greater thickness in the up-down direction than the first electrode. And an electric power source that applies a voltage between the first electrode and the second electrode.