JP2006000801A - Charge injection type electrostatic oil cleaning apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an economical electrostatic oil cleaning apparatus having a high trapping efficiency of contaminant in oil. <P>SOLUTION: In this electrostatic oil cleaning apparatus, multiple pairs of electrodes with one electrode sides formed in a shape having a lot of sharp lugs, and the other ones formed in a smooth shape, are installed in a casing 1. The casing 1 and the smooth electrodes 3 are grounded, high DC voltage is applied to the electrodes 2 having the lugs, and a large amount of charge having the same polarity as the polarity of the electrodes 2 is injected into oil from a vicinity of tips of the lugs, to adhere a large amount of the injected charge to the contaminant in oil passing through between the electrodes. Contaminant charged with the same polarity as that of the electrodes 2 is attracted to the smooth electrodes 3 and inner face of the casing 1 having the reverse polarity by intensive electrostatic force, to trap contaminant. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrostatic oil purifier for removing and purifying contaminants mixed in various oils such as lubricating oil, hydraulic oil, vacuum pump oil, and cutting oil.

  Conventional electrostatic oil purifiers have a structure in which smooth positive and negative electrode pairs having no protrusions are arranged in parallel or concentric circles, and most of the electrostatic oil purifiers between them are between both electrodes. The filter is made of a dielectric material such as paper having a dielectric constant greater than that of oil.

Contaminants in oil are often charged due to preferential adsorption of ions in oil on the surface of contaminants and ionization of particle surface ionization groups, so treated oil containing contaminants was applied with a high DC voltage. When it flows in between the electrode pairs, it moves toward the electrode having the opposite polarity to the charged polarity of the contaminant by the action of the Coulomb force and is captured. When a dielectric filter having a dielectric constant greater than that of oil is inserted between the electrodes, a negative polarization charge appears on the filter surface facing the positive electrode, and the filter surface facing the negative electrode Since a positive polarization charge appears, charged contaminants are also trapped on the filter surface where a polarization charge having a polarity opposite to the charged polarity of the contaminants appears.

Also, in places where a high electric field is locally formed, such as a bent portion of a dielectric filter, gradient force acts due to distortion of the electric field, and even if contaminants are not charged, the gradient force acts on the filter. The heading force acts. As a result, it is possible in principle to capture even uncharged contaminants.

  However, since the conventional electrostatic oil purifier uses the phenomenon that contaminants naturally charge in oil, depending on the compatibility of the contaminants and ions in the oil, there is little or no charged contaminants. Exists. In addition, the magnitude of the gradient force is extremely smaller than the Coulomb force, and the magnitude is proportional to the volume of the contaminant, so the magnitude of the gradient force that attracts the small contaminant is much smaller. As a result, it can take a considerable amount of time to clean, or there may be contaminants that cannot be removed at all.

One of the conventionally proposed methods for improving the oil purification speed is to increase the surface area of the filter and the bent part, or to devise the filter shape, such as making the eyes finer, thereby improving the oil purification speed to some extent. However, there are new problems such as increased filter costs and clogging. In addition, a method has been proposed in which the electrode pair is composed of a perforated flat plate with a large number of holes, and the trapping efficiency is increased by utilizing a high electric field formed around the edge of the hole. Is not expected to improve significantly.
JP-A-56-163713

  The problem to be solved is that it takes a long time for the oil purification treatment of the electrostatic oil purifier.

  The present invention relates to an electrostatic oil purifier provided with a plurality of electrode pairs, an electrode having a large number of sharp protrusions on one end of the electrode (protrusion electrode), and no protrusion on the other side of the electrode pair. Electrode (smooth electrode), and by applying a DC high voltage to the protruding electrode by grounding the smooth electrode, a large amount of charge having the same polarity as that of the protruding electrode is injected into the oil from the protrusion. It is characterized in that a large amount of electric charge is forcibly adhered to the contaminant and the contaminant is efficiently captured by a strong electrostatic force on the smooth electrode surface.

  The electrostatic oil purifier of the present invention injects a large amount of charge into the oil from the vicinity of the protrusion tip of the protrusion electrode to increase the amount of charge of the contaminant, so that the contaminant can be strongly attracted to the smooth electrode surface. And improve the trapping efficiency of contaminants.

In order to facilitate the purification, the oil viscosity is usually lowered by heating with a heater, but most of the power consumption of the electrostatic oil purifier is due to the heater, and the time required for purification when using the apparatus of the present invention. The power consumption can be reduced.

The conventional electrostatic oil purifier has a common point such that the time required for purification is long for the size of the outer dimensions and is expensive, but the apparatus of the present invention is a device because of high capture efficiency. The overall size can be reduced, thereby making it possible to reduce the price.

Since the electrostatic oil purifying apparatus of the present invention efficiently captures contaminants in the oil on the smooth electrode surface with a strong force, it is not necessary to use a filter, which also leads to cost reduction.

  A structure has been realized in which charges can be efficiently injected into oil and contaminants can be easily and firmly captured.

  FIG. 1 is a cross-sectional view of one embodiment of the apparatus of the present invention. A is an apparatus main body, and a protruding electrode (high voltage electrode) 2 and a smooth electrode (ground electrode) 3 are arranged opposite to each other inside a grounded casing 1. Although FIG. 1 shows the case of five protruding electrodes and four smoothing electrodes, the number can be arbitrarily set. The treated oil is supplied from the inlet 4 by a pump and purified while passing through the interior of the oil purifier, then flows out from the outlet 5 and returns to the tank 6 to repeat the oil purification process. When the viscosity of the oil is high, the oil is heated by the heater 7 to lower the viscosity, thereby facilitating the capture of contaminants.

  In the above configuration, when a DC high voltage is applied to the protruding electrode 2, a charge having the same polarity as that of the protruding electrode is injected into the oil from the vicinity of the protruding tip, and adheres to the contaminant surface. Captured by the smooth electrode 3 of opposite polarity.

  FIG. 2 is an example of the result when the electrostatic oil purifying apparatus of the embodiment shown in FIG. Several projecting electrodes with different projecting shapes were manufactured. FIG. 2 shows the results when using projecting electrodes manufactured from punching metal. For comparison, an experiment was also conducted when the protruding electrode was replaced with a flat plate electrode. In the oil purification experiment, oil obtained by mixing JIS test powder I, 11 types (median diameter range of 1.6 to 2.3 mm) at a concentration of 1 g / l with a commercially available hydraulic fluid was used. The size is 9 kV. When the protruding electrode is used, the oil purification rate is faster than when the flat electrode is used, and the ratio of the contaminants finally remaining is also small. Is recognized.

FIG. 3 is a photograph showing the state of trapping contaminant particles during the experiment shown in FIG. In both cases where the protruding electrode was made positive and negative, the contaminant particles were captured on the smooth ground electrode surface, and were captured so that the position facing the protrusion of the protruding electrode was raised. This indicates that charges having the same polarity as the protruding electrodes were injected into the oil, and the injected charges adhered to the contaminant particles. Furthermore, the trapped contaminant particles were kept without being detached from the smooth electrode plate into the oil even when the applied voltage was zero. On the other hand, in the case of the flat plate electrode pair, most of the contaminant particles trapped on the electrode surface with the power interruption were separated and redispersed in oil. From this, it can be understood that in the electrostatic oil purifier according to the present invention, contaminants are captured by the smooth electrode with a strong force.

FIG. 4 is an example of a photograph showing a state of capturing contaminants when an oil purification experiment is performed using actual used waste oil. Even in the actual contaminated oil in which many kinds of contaminants are mixed, the contaminants are trapped on the smooth electrode surface as in FIG.

  Since the electrostatic oil purifying apparatus of the present invention has high removal efficiency of contaminants, it can be downsized and can be manufactured at a low price. Therefore, it is an industry that uses various oils including lubricating oil and hydraulic oil. It is possible to reduce the amount of waste oil and the cost by repeatedly using the oil.

It is explanatory drawing which showed the charge injection type electrostatic oil purifier. (Example 1) It is an example of the oil purification experiment result by a charge injection type electrostatic oil purifier. It is an example of the capture | acquisition state of the contaminant by an electric charge injection type electrostatic oil purifier. It is an example of the capture | acquisition state of the contaminant by an electric charge injection type electrostatic oil purifier.

Explanation of symbols

A Charge injection type electrostatic oil purifier 1 Device housing 2 Projection electrode (high voltage electrode)
3 Smooth electrode (ground electrode)
4 Inlet 5 Outlet 6 Tank 7 Heater 8 Insulating plate

Claims (1)

In an electrostatic oil purifier provided with a plurality of electrode pairs, an electrode having a number of sharp protrusions on one end of the electrode (hereinafter referred to as a protruding electrode) and an electrode having no protrusion on the other side of the electrode pair (Hereinafter referred to as “smooth electrode”), and by applying a DC high voltage to the protruding electrode while grounding the smooth electrode, a large amount of charge having the same polarity as that of the protruding electrode is injected into the oil from the protrusion. An electrostatic oil purifier characterized in that a large amount of electric charge is forcibly adhered to the contaminant and the contaminant is efficiently captured by a strong electrostatic force on the smooth electrode surface.