JPH0470930B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for backwashing a hanging type filter.

Filter to be cleaned In the present invention, a filter in the form of a multi-threaded thin pipe is to be backwashed. This filter is molded as a hollow fiber porous membrane using polyvinyl alcohol, and its outer diameter is approximately 800 microns.
Moreover, its inner diameter is about 400 microns, and the thickness of the filtration membrane is therefore about 200 microns. The filtration membrane has continuous fine pores of about 0.2 to 0.5 microns evenly formed along its axial direction. These filters are housed inside the casing with their lower ends closed and bundled at their upper ends to form a precision filtration membrane within the casing. The filtration capacity of this filter gradually decreases as filtration progresses due to clogging with suspended matter. Therefore, it is necessary to clean the filter at an appropriate time.

Prior Art Conventionally, filter cleaning has been carried out by emptying the inside of the casing and backwashing with air or a chemical solution. However, during air backwashing, sludge and the like in the pores are not sufficiently peeled off and dispersed, making it impossible to perform adequate cleaning, resulting in shorter cleaning cycles.
However, when chemical cleaning is performed, the filtration ability of the filter is almost restored to its initial state. However, such chemical cleaning requires a dedicated chemical processing device and requires a long cleaning time, so that the filtration work cannot be performed continuously. Under these circumstances, an effective cleaning method is desired for the filters to be cleaned.

OBJECTS OF THE INVENTION Therefore, an object of the present invention is to enhance the effect of air backwashing and shorten the backwashing time, since no chemical liquid is used.

SUMMARY OF THE INVENTION Accordingly, the present invention provides ultrasonic vibration to the filter during air backwashing to quickly remove floating substances attached to the micropores of the filter. The external force of such ultrasonic vibrations is effective in liberating suspended substances from the micropores of the filter, but these free suspended substances are trapped between the bundles of filters and are restrained by them. It is difficult for people to go outside. Therefore, in the present invention, during air backwashing, a liquid such as an undiluted solution, a filtrate, or a cleaning solution is previously stored inside the housing, and suspended substances are dispersed in this solution. That is, this liquid also permeates between the filter bundles, and causes the substances separated by the vibrational external force to be dispersed and fall to the outside of the filter bundles. Therefore, the sludge after peeling falls in a dispersed manner to the outside of the multi-filter suspended filter, and can be easily taken out together with the liquid. By such air backwashing, the filtration capacity of the filter is fully restored in a short period of time, and the separated sludge can be easily discharged together with the liquid.
and be able to process it.

Configuration and Function of Filtration Apparatus Hereinafter, one embodiment of the filtration apparatus, which is the premise of the present invention, will be specifically described based on the drawings.

First, FIG. 1 shows an electrolyte filtration device 1 as an example. This filtration device 1 is provided with a filter 3 in the shape of a multi-thread hanging thin pipe to be cleaned, that is, inside a housing 2. As already mentioned, this filter 3 is formed into a hollow shape mainly made of polyvinyl alcohol, is closed at the lower end, and is hung in a bundled state inside the housing 2 by the holder 4 above. It is being The housing 2 has a raw liquid inlet 5, a filtrate inlet 6, and an air vent 7 in its upper part, and a liquid outlet 8 in its lower part.

The stock solution 10 to be filtered is sent into the settling tank 9 from the electrolytic processing machine 11 . Stock solution 1 in settling tank 9
The supernatant of 0 passes over the overflow weir 12,
It enters the stock solution tank 13 and is supplied to the filtrate port 5 by a stock solution pump 14 via a solenoid valve 15 and a pressure switch 16 with an indicator. During this initial supply, the solenoid valve 17 connected to the air vent 7 is open, allowing the air inside the housing 2 to exit to the outside.

The stock solution 10 inside the housing 2 is fed into the inside of the hollow filter 3 from the outside through the fine holes 3a as shown in FIG. enter,
It is sent out to the filtrate port 6 as a filtrate 20. Two solenoid valves 18 and 19 are connected to this filtrate port 6, but since the solenoid valve 18 is closed during this filtration process, the filtrate 20 is transferred to the open solenoid valve 1.
9 and an integrated water meter 21, the filtrate tank 2
It is housed inside 2. The filtrate 20 in the filtrate tank 22 is sent to the electrolytic processing machine 11 as a new electrolyte by the pump 23. In addition, the concentrated liquid 24 at the bottom of the settling tank 9
is discharged to the outside as a cake by, for example, the filter press 25, and the filtrate at that time is sent into the settling tank 9 again. Further, the sludge at the bottom of the housing 2 is sent to the settling tank 9 via the liquid outlet 8 by the solenoid valve 29. And these solenoid valves 15, 17, 18, 19, 2
9 is in a relationship controlled by a controller 28 which receives the signal from the pressure switch 16 as an input.

Through such a filtration cycle, the stock solution 10, that is, the electrolyte solution, is recycled and used while removing suspended substances such as processing waste from the solution under an external pressure filtration method.

Backwashing process When such filtration is performed continuously, the stock solution 1
The suspended solids contained within the filter 3 clog the micropores 3a of the filter 3, resulting in a so-called clogged state, resulting in a decrease in filtration ability and a gradual increase in filtration pressure. When the filtration pressure exceeds a certain value, pressure switch 16 is turned on and sends a signal to controller 28. Therefore, the controller 28 closes the solenoid valves 15, 19, and 22 and opens the other solenoid valves 17 and 18 in order to perform backwashing.

Now, the backwashing method of the present invention is performed by air backwashing. Air 30 for backwashing is supplied from a pressure air source 26 and set at a predetermined pressure by a regulator 27, and passes through a solenoid valve 18 that is open during backwashing.
The filtrate is supplied to the filtrate port 6. At this time, air 30
is sent into the inside of each filter 3, and the micropores 3 are closed by pressure in the opposite direction to the filtration direction.
Floating substances, ie, sludge, in a are separated from the filter 3. Inside the housing 2, there is a source liquid 1.
Since air 30 or filtrate 20 or special cleaning water is stored in advance, the backwashing air 30 becomes bubbles in the housing 2 as it passes through the micropores 3a of the filter 3 during the backwashing process. It rises in the internal liquid and is released into the atmosphere through the air vent 7.

During or after this air blowing, ultrasonic vibration is applied to the filter 3 by the vibrator 31.

FIG. 3 shows an example in which the vibrator 31 is fixed to the upper surface of the holder 4. This holder 4 is fixed inside the housing 2 by a vibrating damper 33. This vibrator 31 is connected to the air 3
Since ultrasonic vibrations are applied to the filter 3 during or after blowing, suspended substances, that is, sludge, released from the micropores 3a of the filter 3 pass through the gaps between the bundled filters 3 and are affected by the vibrations of the filter 3. While being biased, it disperses into the liquid inside the housing 2 and falls to the bottom. Thereafter, the liquid inside the housing 2 is supplied to the inside of the settling tank 9 through the liquid outlet 8 together with the sludge.

Next, FIG. 4 shows an example in which a vibrator 31 is attached to the lower end portion of the filter 3 in a non-contact manner. This vibrator 31 applies direct ultrasonic vibrations to the internal liquid of the housing 2, but also indirectly applies ultrasonic vibrations to the filter 3 through the liquid.

In this way, in the present invention, the air 3 for backwashing
0 is sent into the inside of the filter 3 from the direction opposite to the filtration direction to separate the sludge from the micropores 3a, and at the same time or afterwards the vibrator 31 applies a vibratory external force to the filter 3 directly or indirectly. , the sludge after separation is passed through filter 3.
The liquid is discharged to the outside through the gap, and disperses and falls into the liquid inside the housing 2. In this manner, in the backwashing process, the jet of air 30 in the opposite direction and the external force acting on the filter 3 act on the filter 3, so that a high cleaning function can be obtained in a short time due to the synergistic function of the two in the liquid. This cleaning effect is not as good as chemical cleaning, but in a short time,
This is advantageous in that it provides sufficient functionality for practical purposes.

Effects of the Invention In the present invention, the function of the filter can be restored in a short time by air backwashing in the liquid and application of an external force of ultrasonic vibration, and therefore the backwashing cycle can be set for a long time. In particular, in the present invention, sludge is separated from the micropores of the filter by air backwashing,
Since the sludge after peeling is dispersed and dropped into the liquid by the external force of the subsequent ultrasonic vibration, a sufficient backwashing effect can be achieved in a short time, and moreover, only by temporarily stopping the filtration process. Further, the method of the present invention can be implemented without making any major structural changes to conventional filtration devices, so it can be easily implemented in existing devices.

[Brief explanation of drawings]

Figure 1 is a piping diagram of the filtration device, Figure 2 is a theoretical enlarged sectional view of a part of the filter, Figure 3 is a side view of a part of the mounting area of the vibrator and filter, and Figure 4 is vibration against the housing. FIG. 3 is a cross-sectional view of the attachment part of the child. 1...Filter device, 2...Housing, 3...Filter, 4...Holder, 5...Filtrate port, 6...
...Filtered liquid inlet, 7... Air vent, 8... Liquid outlet, 9... Sediment layer, 10... Stock solution, 11... Electrolytic processing machine, 12... Overflow weir, 13... Stock solution tank, 14... ...Standard pump, 15...Solenoid valve, 1
6... Pressure switch, 17, 18, 19... Solenoid valve, 20... Filtrate, 21... Integrating water meter, 22
...Filtrate tank, 23...Pump, 24...Concentrate, 25...Filter press, 26...Pressure air source, 27...Regulator, 28...Controller, 30...Air, 31...Vibration Child, 33...
damper.

Claims (1)

[Scope of Claims] 1. A filtration method using a filtration device consisting of a housing having a raw solution inlet and a filtrate inlet, these inlets and the filtrate inlet communicating through a filter in the form of a multi-thread hanging thin pipe. , put liquid such as stock solution, filtrate, or washing water in the housing, blow air for backwashing from the filtrate port, and apply ultrasonic vibration to the filter using a vibrator placed inside the housing. , a method for backwashing a hanging filter, characterized by peeling off sludge adhering to the filter. 2 Claim 1 characterized in that ultrasonic vibration is applied after blowing air for backwashing.
How to backwash a hanging filter as described in section.