JPS5836664A - Refining method for liquid - Google Patents

Abstract

PURPOSE:To obtain refined liquid of high clarity with a series of stages by applying an electric field to the liquid to be refined, then allowing the liquid to stagnate for a required time in a flocculating tank having electrical insulation characteristics thereby allowing fine particles to grow coarsely. CONSTITUTION:Liquid to be refined is pumped 1 into an ionizing tank 2, and receives the effect of an electric field in the tank 2, whereby the particles contained in the liquid is charged or polarized. The liquid receiving the effect of the electric field flows immediately into the next flocculating tank 4, and is allowed to stagnate for a constant time in the tank 4. Then the charged or polarized particles in the liquid are attracted to each other by Coulomb force, thus joining and growing to large particles. When the liquid flows from the tank 4 into the next removing means 5, the grown coarse grains in the liquid are removed, whereby the liquid is clarified.

Description

[Detailed description of the invention] This invention applies not only to oil fluids such as insulating oil.

It relates to purification methods for purifying various liquids such as water.

Among the contaminant particles contained in a liquid such as an oil solution, it is extremely difficult to remove particles with a size of 5 μm or less using a conventional method such as Pa. This is because the particles are so small that they are not sufficiently affected by gravity, centrifugal force, or the suction force of the adsorbent. Among them, colloidal particles, which are particles smaller than 0.1 μm, undergo free movement called Brownian motion in the liquid, and they become charged and repel each other due to collisions of this movement, so they do not settle forever and cannot be removed normally. cannot be removed by any method.

On the other hand, in recent years, with the advancement of industrial technology, it has become necessary for liquids used such as insulating oil to have a purity of 1μ or less, and there is a strong demand for methods for producing highly purified liquids. Applying an electric field to the liquid to be purified,
A method has been developed to remove microparticles by attracting them to an electrode or a dielectric between electrodes using Coulomb force, but as mentioned above, Coulomb force does not act sufficiently on colloidal particles, so the same process f: This process must be repeated 5 or 10 times, resulting in low processing efficiency.

By the way, when the inventor of this invention observed the extent to which microparticles were attracted to the electrode and the dielectric material in the above method, it was found that particles of 5μ or more were directly attracted to the electrode at equal pressure, but
There was a fact that particles smaller than μ were not immediately attracted, but were rapidly attracted after a certain period of time. This phenomenon occurs when particles of 5μ or less become electrically charged, then attract each other by Coulomb force and coalesce, gradually growing into larger particles, and only when the particle size reaches a size large enough to overcome the resistance of the liquid are they attracted to the electrode. This is thought to be due to the They have also discovered that particle growth occurs rapidly in insulating containers such as glass containers.

This invention was made based on the above observation results, and its gist is as follows.

After applying an electric field to the liquid to be purified and electrifying and polarizing the microparticles in the liquid, the liquid is retained in an electrically insulating tank until the microparticles grow to a sufficient size. This is then sent to a coarse particle removal means such as a filter.

The details of this invention will be explained below based on the illustrated embodiments! In Figure 1, an IFi pump, 2 an ionization tank, an sFi power supply, and a coagulation tank for retaining the liquid to be purified for a required period of time have electrical insulation properties. ε is a means for removing coarse particles such as a filter. Various types of ionization tank 2 can be used, but in this example, as shown in FIG. 2, a cylindrical tank body St and one electrode are used.
There is a kumquat in which circular plate electrodes 7 are arranged in stages by pillars 8.

The liquid to be purified is fed into the ionization tank 2 by the operation of the pump 1, and is fully subjected to the action of an electric field within the tank 2, whereby the particles contained in the liquid are charged or polarized. In the case of an insulating liquid, the electric field applied in this ionization tank 2 is
Assuming 3Qwsm, the electrostatic electric field is 10 to 20 KV, and in the case of a non-insulating liquid, it is appropriate to set the electrostatic electric field to 30 V or more with the above-mentioned inter-electrode spacing.

The liquid thus subjected to the electric field immediately flows into the next coagulation tank 4 and remains in #tank 4 for a certain period of time. As a result, the charged or polarized particles in the liquid attract each other due to the Coulomb force, coalesce, and grow into large particles. in this case.

Since the particles are hardly affected by the flow of the liquid and are not affected by external electrical influences due to the insulation of the coagulation tank 4, their coalescence growth is promoted and they quickly become coarse particles. The aggregation tank 4 may be any material as long as it has electrical insulation properties, and the entire tank may be made of an insulating material such as kFRP.

It is also possible to use an insulating lining on the inner surface of the tank body made of gold. Further, it is also possible to support the tank with an insulating material and provide an insulating connection part between it and other equipment to provide an insulating metal.

As fine particles grow into coarse particles in the flocculation tank 4, removal by existing removal means such as filters is reduced to 1I.
Becomes IT Noh. Therefore, when the liquid flows from the coagulation tank 4 into the next removing means 6, the grown coarse particles in the liquid are removed and the liquid is purified. In addition to the above-mentioned filter, the removal means may include a centrifugal separator and an electrostatic purifier*1 that removes particles by adsorbing them to an electrode.

The residence time in the coagulation tank 4 is set depending on the ability of the coarse particle removal means. That is, the finer the filter mesh, the shorter the darkness during fl storage, and the larger the filter mesh, the longer the retention time.

Incidentally, if a means for removing coarse particles such as a filter also has electrical insulation properties, the effect of coarsening the particles is further promoted.

In this way, in #4h, after applying an electric field to the liquid to be purified, this liquid is allowed to stagnate in a coagulation tank and is first applied to coarse particle removal means, which cannot be easily removed using conventional methods. Since the remaining microparticles grow coarsely and are removed by the removal means, a highly clean purified liquid can be obtained all at once in a series of steps, making continuous purification possible.

[Brief explanation of the drawing]

Fig. 4 is a process diagram of the method of this invention, and Fig. 2 is a partially cut-away side view of the ionization tank. 1...Pump, 2...Ionized Hinoki. 4...Agglomeration tank, 6...Means for removing coarse particles Patent applicant Inoue Sangyo Co., Ltd. Agent Patent attorney Iwaodo Sugi Patent attorney Katsunori Sugisue 11th prisoner

Claims (1)

[Claims] 1. After applying an electric field to the liquid to be purified, this liquid is retained in an electrically insulating sputum tank for the required time before being sent to coarse particle removal means such as a filter or centrifuge. A liquid purification method characterized by: