JPH03238010A - Filter apparatus together using positive and negative charge type filter materials - Google Patents

Abstract

PURPOSE:To perform perfect filtering by arranging a filter receiving two kinds of positively and negatively charged filter materials and perfectly preventing the bonding of the colloidal foreign matter in a solution to the filter materials permitting the solution to pass finally by electrical repulsive force. CONSTITUTION:Positively and negatively charged filter materials 1, 3 are individually received in filter apparatuses 2, 4. Communication piping equipped with valves 6-9 making the communication and separation of respective filter chambers possible is provided. The filter chamber receiving the filter material having potential of the same tendency as the charged potential of the interface of the colloidal substance suspended in a solution to be filtered among both filter chambers is always used as a filter permitting the solution to pass finally and the filter chamber receiving the filter material having potential of a tendency different from the interface charge potential of the colloidal substance is used as the auxiliary filter of the solution. The valves of the communication piping system connecting the filter chambers are changed over to alter the arrangement of both filter chambers and the above-mentioned operation can be performed even with respect to both positive and negative charge potentials of the colloidal substance in the solution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for filtering high purity solutions containing trace amounts of colloidal substances.

[Conventional technology]

Conventional filters for high-purity solutions generally use a method to physically remove foreign substances using a filter material with ultrafine pores that does not have an electric charge. A method using filter media has also been adopted. However, even when using this charged filter material, by using a filter material that has a potential that is different from the interfacial potential (ζ potential) of the colloidal substance in the filtration solution, the micropores of the filter material can be A method of increasing the filtration effect is to physically filter out flammable foreign matter, and to remove foreign matter that is smaller than the micropores of the filtering material, the colloidal material is adsorbed to the filtering material due to the potential difference between the colloidal material and the filtering material, thereby increasing the filtration effect. .

By selecting an excellent filter material, it is possible to obtain a certain degree of filtration effect, but when using a filter material that is not charged, foreign matter with dimensions smaller than micropores will not pass through. It is difficult to say that it is a perfect filtration method because it is stored away. In addition, a method using a filter material that has a potential that is different from the interfacial potential (ζ potential) of the colloidal substance in the filtration solution can be expected to have a better filtration effect than an uncharged filter material, but the pores are smaller than the captured micropores. Since filtration foreign matter is attached to the surface of the filtration material, there is a possibility that the foreign matter once attached to the filtration material will be separated and flowed out to the outlet of the filtration material due to a sudden increase in flow rate or pulsation of the fluid. Complete filtration is impossible, and foreign matter accumulated on the surface of the filter material increases flow resistance during removal, eventually requiring replacement or cleaning of the filter material. Thereafter, when the filter is restarted, there are problems such as foreign matter flowing into the piping system that requires ultra-purity.

[Problem that the invention seeks to solve]

The present invention was proposed in view of these circumstances, and because colloidal foreign matter in the solution does not adhere to the filter material through which the solution ultimately passes due to electrical repulsion, it is completely eliminated. In addition, even if other auxiliary filter media are replaced or cleaned, there will be no problem of minute foreign matter passing through the filter and entering the piping system.
It can be used with confidence even in places that require ultra-high purity.

[Means for solving problems]

(5) (6) For this reason, the present invention provides a positive (+) potential and a negative (-) potential within the filtration device.
) Connecting each filtration chamber with a filtration chamber that individually stores filtration media charged with electric potential, and a connecting pipe equipped with a valve to enable communication and isolation between the filtration chambers. The arrangement of both filtration chambers can be changed by switching the valves in the connecting piping system, making it possible to handle solutions containing colloidal substances of any interfacial potential (ζ potential). It is characterized by the following.

[Effect]

With such a configuration, it is possible to obtain a filtration device that can filter even ultrafine colloidal substances in a solution and create an ultrapure solution, which was impossible with conventional filters.

Example An embodiment of the present invention will be described with reference to the drawings.

Figure 1 shows the main filter through which the solution finally passes, the auxiliary filter installed in the recirculation system for the solution in the filter, and the piping and valves that can switch the arrangement of both types of filters. FIG. 2 is a system diagram showing a filtration device having an auxiliary prefilter arranged in series, a main filter through which the solution finally passes,
It is a system diagram showing a filtration device having piping and valves that can reverse the arrangement of both types of filtration devices.

In FIG. 1, 1 is a filter material charged with a negative (-) charge, and 2 is a filter 3 that stores the filter material 1.
), 4 is a filter that stores the filter medium 3, 6 is an inlet switching valve for both types of filters, and is a three-way valve that makes it possible to select between the filters 2 and 4 by switching the valve. , 7 is an outlet switching valve for both types of filters, and if possible, it is possible to select communication between the outlet pipe of the filter 2 or the filter 4 to either the filtration device take-out pipe 11 or the recirculation pipe route 12. 8 is a 3-way valve that allows the recirculation piping route to communicate with either filter 2 or 4 by switching the valve; 9 is a communication valve between filter 2 and filter 4; It is. Further, 5 is an inlet pipe to the filtration device, 11 is an outlet pipe of the filtration device, 12 is a recirculation pipe, and 10 is a water pump installed in the recirculation pipe route.

(7) (8) In the filtration device, the solution to be filtered contains various colloidal substances, and each colloidal substance has a unique interfacial potential (ζ potential) in the solution, Physically, there are plus (+) and minus (-) depending on the type of colloidal substance.
), there is a mixture of substances that have the characteristic of being charged at both potentials, but when looking at the colloidal substances in the solution macroscopically, the potential of a small amount of colloidal substances is canceled out by the dominant amount of charged colloidal substances. The foreign matter in the solution is charged to either a positive (+) or negative (-) potential. Therefore, for example, when the colloidal substance in the solution to be filtered is negatively charged (-), the solution flowing from the inlet pipe 5 is sent to the filter 2 by switching the inlet switching valve 6. At this time, the negatively charged colloidal substances electrically repel the negatively charged filtering material 1, and the colloidal substances cannot return to the filtering material 1. A transparent layer is formed on the surface of the filtration material 1 so that only the pure solution passes through the filtration material 1.
Complete filtration takes place here as it exits the filtration device through the filtration device.

However, if the filter is operated for a long time in this state, the concentration of colloidal floating substances in the filter 2 will increase, the transparent layer will gradually disappear, and eventually the filtering performance will deteriorate. Therefore, the concentration sensor or timer installed in the filter 2 closes the valves in the recirculation piping route, starts the water pump 10, and transfers the solution containing colloidal suspended solids to the recirculation piping route. Circulate. With this operation,
Colloidal substances that are negatively charged (-) are positively charged (
The colloidal suspended solids in the filter 2 are electrically attracted to the charged filter material 3 and returned to the filter 2 after being completely filtered by the filter 4, so that the concentration of colloidal suspended solids in the filter 2 decreases. In such a device, continuous operation of the filter 2 is possible because no colloidal suspended solids adhere to the filter material, and
Since the filter 4 that stores the filter material 3 does not need to be operated continuously, the filter material 3 can be cleaned or replaced while the filter 2 is in operation.

Furthermore, when the colloidal substance in the solution is positively charged (9) (10), exactly the same filtration operation is possible by switching valves 6, 7, and 8. .

In FIG. 2, the filtration device has a pre-filter and a post-filter arranged in series, 21 is a negatively charged filter material, and 22 is a filter housing the filter material 21. ,
23 is a positively charged filter material, 24 is a filter that stores the filter material 23, and 26 is a four-way switching valve that selects the arrangement of the filters 22 and 24 by switching the valve, and serves as a prefilter. It also constitutes a piping route for sending the solution to the filter used as a pre-filter and for sending the solution exiting the pre-filter to the post-filter. Reference numeral 27 denotes a four-way switching valve that configures a piping route for sending the solution exiting the pre-filter to the post-filter by switching the valve, as well as a piping route for taking out the solution exiting the post-filter to the outside of the filtration device. It is a valve that can also be configured.

Further, 25 is a solution inlet pipe, 28 is a communication pipe, and 29 is a solution outlet pipe.

In this filtration device, when the colloidal substance in the solution to be passed is negatively charged, the solution flowing from the inlet pipe 25 is sent to the filter 24 by switching the inlet switching valve 26. At this time, the negatively charged colloidal substance is electrically adsorbed to the positively charged filtering medium 23, and the colloidal substance is completely filtered by the filtering medium 23. Furthermore, the solution that exits the pre-filter is sent to the post-filter, and although this solution contains almost no colloid, even if there is a trace amount of colloid. Since the substance has a negative (-) interfacial potential (ζ potential), it electrically repulses each other with the filtering material 21 and cannot write back to the filtering material 21, so a transparent layer is formed near the surface of the filtering material 21. Complete filtration is achieved here, as only the pure solution passes through the filter medium 21 and exits the filtration device through the four-way switching valve 27 and the outlet pipe 29. If the operation is continued for a long time in this state, colloidal pollutants will adhere to the surface of the filter medium 23 in the prefilter 24, increasing the pressure head at the filter medium 23, and eventually , a decrease in filtration performance occurs. At this time, the filter 23
Clean or replace the filter media by switching to the spare unit. Furthermore, in the filter 22, a small amount of colloidal material leaks into the solution with a negative (-) interfacial potential (ζ
Even if there is a very small amount of colloidal suspended matter that has a negative (-)
Continuous operation is possible because it does not adhere to the surface of the filter medium 21, which is electrically charged.

Furthermore, when the colloidal substance in the solution has a positive (+) interfacial potential (ζ potential), exactly the same filtration operation can be performed by switching valves 26 and 27 and operating in the opposite piping route. It is possible.

〔Effect of the invention〕

According to the present invention, in order to completely remove trace amounts of colloidal substances contained in a solution, a filter containing at least two types of filter media charged with positive (+) and negative (-) charges is provided. It is equipped with a system switching device that prevents the passage of colloidal substances by utilizing both electrical repulsion and adsorption phenomena, and corresponds to the interfacial potential (ζ potential) of colloidal substances in the solution. Continuous operation is possible by
In addition, since a high-performance filtration device can be obtained, the present invention is extremely useful industrially.

[Brief explanation of drawings]

Figure 1 is a system diagram showing a filtration device having a main solution filter, an auxiliary filter installed in the recirculation system for the solution in the filter, and piping and valves for switching the arrangement of both wave filters. . Second
The figure is a system diagram showing a filtration device that has an auxiliary pre-filter arranged in series, a main filter that finally passes the solution, and piping and valves that reverse the arrangement of both wave filters. It is. 1... Minus (-) charged filter material, 2... Minus (-) charged filter, 3... Plus (+) charged filter material,
4... Plus (+) charged filter, 5... Solution inlet piping, 6... Filter inlet switching valve, 7... Filter outlet switching valve, 8... Switching valve, 9...・Communication valve, 10... Water pump for recirculation, 11... Solution outlet piping, 12...
・Recirculation piping, 13... continuous pipe. 21... Minus (-) charged filter material, 22... Minus (-) charged filter, 23... Plus (13) (14) (+) Charged filter material, 24... Plus (+) Charged filter, 25... Solution inlet piping, 26... Filter inlet switching valve, 27... Filter outlet switching valve, 28... Communication pipe,
29...Solution outlet piping. (15)

Claims (1)

[Claims] 1. In a filtration device that filters a highly pure liquid using a charged filtration material, the inside of the filtration device is charged with a positive (+) potential and a negative (-) potential. A filtration chamber that individually stores at least two filtration media, a connecting pipe equipped with a valve to enable communication and isolation between the filtration chambers, and a filtration chamber that contains at least two filtration media. A filtration chamber containing a filtration medium having the same tendency as the charged potential (ζ potential) at the interface of the colloidal material suspended in the surface is always used as the final flow filter for the solution, and the interfacial charged potential (ζ potential) of the colloidal material suspended in the It is possible to use a filtration chamber containing a filtration medium having a potential trend different from that of the filtration chamber as an auxiliary filter for the solution, and to switch the valve in the connecting piping system connecting each filtration chamber. It is equipped with piping and valves that enable the arrangement of both filtration chambers to be changed and the above operation to be performed for either the positive or negative charged potential (ζ potential) of the colloidal substance in the solution. A filtration device for high purity solutions. 2. At least two filter media charged with positive (+) and negative (-) potentials are stored individually, and connecting piping is connected via valves installed between these filter chambers; One of the two filtration chambers serves as a main filter for filtering the solution through the solution, and the other serves as an auxiliary filter installed in the solution recirculation pipe line in the main filtration chamber; Piping and valves that enable the chamber to be easily changed to either a main filtration chamber for solution passage or an auxiliary filtration chamber for solution recirculation by switching the valve, and the recirculation piping line. A filtration chamber containing a filtration material having a potential having the same tendency as the interfacial charging potential (ζ potential) of the colloidal substance in the filtration solution is always used as a filter through which the solution passes, Further, the method according to claim 1 is characterized in that a filtration chamber storing a filtration material having a potential different from the interfacial charging characteristic (ζ potential) of a colloidal substance is used as a filter for recirculating a solution. Filtration device for high purity solutions. 3. A filtration chamber in which at least two filtration media charged with positive (+) and negative (-) potentials are stored individually and arranged in series, and each filtration chamber is connected in series. piping and valves that enable the arrangement to be reversed by switching the valves in the connecting piping installed between the two filtration chambers,
Of these two filtration chambers, the filtration chamber installed on the downstream side serves as the main filter that ultimately filters the solution through the solution, and the filtration chamber installed on the upstream side serves as an auxiliary prefilter for the main filtration chamber. A filtration chamber containing a filtration material having the same potential as the interfacial potential (ζ potential) of the colloidal substance in the filtration solution is used as the main filter for the final flow of the solution, and the interfacial potential (ζ potential) of the colloidal substance in the filtration solution is
ζ potential) The high temperature filter according to claim 1, characterized in that a filtration chamber storing a filtration medium having a tendency different from the ζ potential) is used as an upstream filtration chamber as an auxiliary prefilter for a solution. Filtration equipment for purity solutions. 4. Interfacial potential (ζ
In a filtration device that processes solutions whose potential (potential) always has a certain tendency to be positive (+) or negative (-), at least two filter media charged with positive (+) and negative (-) potentials are individually charged. A filtration chamber containing a filtration chamber and a connecting pipe installed between the two filtration chambers, and storing a filtration material charged to the same tendency as the interfacial potential (ζ potential) of the colloidal substance present in the filtration solution. The chamber serves as the main filter through which the solution is finally filtered, and the interfacial potential (
A filtration chamber containing a filtration material charged with a tendency different from the ζ potential) can be used as an auxiliary prefilter of the main filter, or as an auxiliary filter installed in the solution recirculation piping in the main filter. A filtration device for high purity solutions having the same technical effect as the filtration device according to claim 1, which is characterized in that it is used.