JPH1157704A - Water purifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To clean the water to be used in cleaning the food, tableware, etc., in the kitchen or used in the livestock and fresh vegetables to prevent the infection due to water by using a hollow-fiber membrane filter as the first filter in the untreated water flow direction and attaching a backwashing mechanism to the filter. SOLUTION: A first filter 1 and a second filter 3 are connected in series with a solenoid valve 2 in between. A branch pipe 9 is connected to the inlet of the first filter 1 through a solenoid valve 8 as a mechanism for backwashing the membrane, and a backwashing pump 5 and a backwashing tank 4 are joined to the outlet in parallel with the solenoid valve 2 through a check valve 6. Further, a check valve 7 is connected to the inlet of the filter 1 on the upstream side of the brach pipe 9 in the raw water flow direction. The untreated water from a city water pipe, etc., is passed through the check valve 7 and filled in the first filter 1. The filtered water is partly stored in the backwashing tank 4 through the solenoid valve 2, and the remainder is sent to the second filter 3, filtered for the second time and discharged as cleaned water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water purification apparatus suitable for washing foods and dishes in a kitchen, and for preventing infectious diseases caused by water used for livestock and fresh vegetables.

[0002]

2. Description of the Related Art Recently, infectious diseases caused by pathogenic Escherichia coli O-157, Cryptosporidium and the like have caused great social unrest. The possibility of contamination of well water and tap water has been pointed out along with various foods and foods, and cases of tap water have been reported.

[0003] In order to prevent such infectious diseases caused by water, as disclosed in JP-A-8-302762,
Tap water is filtered through a hollow fiber membrane, and
As disclosed in Japanese Patent Publication No. 96, filtration of tap water through an activated carbon layer and a hollow fiber membrane is performed. However, although almost aseptic water can be obtained by filtering well water or tap water with a hollow fiber membrane, as filtration continues, pores begin to be clogged by fine particles trapped on the hollow fiber membrane surface. The filtration pressure gradually increases, and the filtration flow rate decreases. To minimize these phenomena,
The hollow fiber membrane surface is regularly backwashed to wash away the trapped fine particles, but if the backwash is repeated, the hollow fiber membrane will be damaged, and this time the capture performance will decrease. ,
The remaining water such as bacteria will flow out. for that reason,
Using these techniques as they are for infection control has problems in terms of reliability and processing capacity.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to wash foods, dishes and the like in a kitchen, and to supply them to livestock and fresh vegetables in order to prevent infectious diseases caused by water.
³ ~ to provide a suitable water purification device to purify tens m ³ scale of water.

[0005]

According to the present invention, there is provided a water purification apparatus comprising a plurality of filters arranged in multiple stages, wherein a filter located first in the flow direction of raw water is a hollow fiber. It is a membrane filter, wherein the hollow fiber membrane filter is provided with a backwashing mechanism. Regarding the flow direction of the raw water, it is preferable to have first and second two filters, and both the first and second filters are hollow fiber membrane filters. In that case, the first
The total area of the hollow fiber filtration membrane of the second filter is preferably 濾過 or less of the total area of the hollow fiber filtration membrane of the filter. Further, the pore diameter of the hollow fiber membrane is preferably in the range of 0.01 to 0.45 μm.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, the water purification apparatus of the present invention has two filters 1, 3 using hollow fiber membranes arranged in multiple stages. The first filter 1 and the second filter 3 are connected in series via a solenoid valve 2. At the same time, as a hollow fiber membrane backwashing mechanism, a branch pipe 9 is connected to an inlet of the first filter 1 via a solenoid valve 8 and an outlet is connected to a backwash pump 5 via a check valve 6. A backwash water tank 4 is connected in parallel with the solenoid valve 2. Further, a check valve 7 is connected to the inlet of the first filter 1 on the upstream side of the branch pipe 9 with respect to the flow direction of the raw water.

As shown in FIG. 2, the first and second filters 1 and 3 have a plurality of cartridges 10 arranged in parallel. Each cartridge 10 accommodates a hollow fiber membrane bundle 12 bent in a U-shape in a transparent resin cylindrical body 11, and seals between the end of the hollow fiber membrane bundle 12 and the cylindrical body 11 with a sealant 13. It is sealed. Then, a plurality of the cartridges 10 are arranged in parallel with the sealing portion facing upward, and the upper portion is
The lower part is connected to the connector 15 respectively.

[0008] Raw water sent from a water pipe or the like passes through a check valve 7 and is filtered by a first filter 1. Part of the filtered water is stored in the backwash water tank 4 via the electromagnetic valve 2, and the rest is sent to the second filter 3, where the second filtration is performed, and the filtered water is discharged as purified water.

The raw water and the filtered water sent to the first and second filters flow to each cartridge 10 via a connector 15 as shown by arrows in FIG. Outflow from 14.

As the filtration proceeds, the first filter 1 is gradually clogged by the fine particles contained in the raw water.
Activate the backwash pump 5 to cause the filtered water stored in the backwash water tank 4 to flow back to the first filter 1 via the check valve 6,
The fine particles attached to the hollow fiber membrane are washed away. At this time, the solenoid valve 2 is closed and the solenoid valve 8 is open. The backwash water containing the separated fine particles is discharged from the branch pipe 9 to the outside of the system. In addition,
A backwash interval of about 1 to 3 times / day is sufficient.

In the above embodiment, the cartridge 10
It is preferable that the hollow fiber membrane used has a pore size in the range of 0.01 to 0.45 μm. That is, when the pores of the hollow fiber membrane are made smaller, the trapping performance is improved, but the water permeability is reduced. On the other hand, when the pores are enlarged, the trapping performance is reduced but the water permeability is improved. In order to satisfy both the capturing performance and the water permeability, the pore diameter is preferably in the above range. As a result, the water permeability is high, and the practical bacteria capturing performance is maintained.

Further, the total area of the hollow fiber filtration membrane of the second filter 3 is 1 / the total area of the hollow fiber filtration membrane of the first filter 1.
It is also preferable to set it to 2 or less. By doing so, in the first filter 1, the total area of the filtration membrane is increased and the filtration rate is low, and in the second filter 3, the first filter 1
The filtered water from which fine particles causing clogging have been removed can be filtered at a large filtration flow rate, and more purified water can be obtained.

Further, in the above embodiment, the case where two filters are used has been described. However, if more filters are connected in series, the hollow fiber membrane of the filters may be damaged by backwashing and bacteria may be removed. In this case, it is possible to more reliably prevent a decrease in the ability to capture bacteria in the event of leakage, and to achieve higher safety. This is because even if the hollow fiber membrane of the first filter is damaged in the flow direction of the raw water and bacteria leak, the bacteria can be removed not only by the next filter but also by a plurality of subsequent filters. In addition, since the number of bacteria in water decreases with each repetition of filtration, even if the filtration flow rate is increased in order to increase the amount of purified water obtained, the eradication rate can be extremely reduced by setting multiple filters in multiple stages. High water purification is obtained.

[0014] The second filter in the flow direction of the raw water may not be a filter using a hollow fiber membrane. It is preferable to use a membrane filter.

[0015]

EXAMPLE A workplace using tap water having an average of 10 m ³ per day was provided with a first filter having a total membrane area of 20 m ² using a hollow fiber membrane having a pore diameter of 0.3 μm, and a pore size of 0 m ^2. 0.3 μm
A water purifier as shown in FIG. 1 having a second filter having a total filtration membrane area of 10 m ² using the hollow fiber membrane was used for 6 months. As a result of measuring the number of bacteria by the membrane filter method, the raw water was 20 to 80 cells / 100c.
Whereas remained at m ^3, clean water is always zero / 100cm ³
Met. The operating conditions were as follows.

[0016] Filtration pressure (actually measured value): 20 kPa (initial): 80 kPa (after implementation for 6 months) Supply water turbidity: <3 degrees Filtration water volume: 2 m ³ / hour Backwash pressure: 200 kPa Backwash flow rate: 2 m ³ / Hour Backwash time: 15 seconds / time Number of times of backwash: 3 times / time Backwash interval: 1 time / day (initial): 2 times / day (after 5 months)

[0017]

According to the water purification apparatus of the present invention, since a plurality of filters are arranged in multiple stages, it is possible to prevent a decrease in bacteria capturing performance due to damage to the first filtration membrane, and to increase a bacteria elimination rate. Can be. At the same time, the first filter located in the flow direction of the raw water is the hollow fiber membrane filter, and the hollow fiber membrane filter is provided with a backwashing mechanism, so that the life of the hollow fiber membrane can be significantly extended. it can. And, regarding the flow direction of the raw water, there are first and second two filters, and both the first and second filters are hollow fiber membrane filters, or the pore diameter of the hollow fiber membrane. Is in the range of 0.01 to 0.45 [mu] m, the water permeability is high, and practical bacteria capturing performance can be maintained. Further, when the total area of the hollow fiber filtration membrane of the second filter is less than or equal to 1/2 of the total area of the hollow fiber filtration membrane of the first filter, it is possible to prevent a decrease in the amount of filtered water due to clogging. , More filtered water can be obtained. From these characteristics, the running cost can be reduced by the water purification device of the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic flowchart of a water purification device according to an embodiment of the present invention.

FIG. 2 is a schematic front view of a first filter and a second filter of the water purification device shown in FIG.

[Explanation of symbols]

 1: First filter 2: Solenoid valve 3: Second filter 4: Backwash water tank 5: Backwash pump 6: Check valve 7: Check valve 8: Solenoid valve 9: Branch pipe 10: Cartridge 11: Cylindrical body 12: Hollow fiber membrane bundle 13: Sealant 14: Connector 15: Connector

Claims (4)

[Claims] In a water purifier comprising a plurality of filters arranged in multiple stages, a filter located first in the flow direction of raw water is a hollow fiber membrane filter, and the hollow fiber membrane filter is backwashed. A water purification device having a mechanism. 2. The method according to claim 1, wherein the flow direction of the raw water is first and second.
The water purification device according to claim 1, comprising two filters, wherein both the first and second filters are hollow fiber membrane filters. 3. The water purification apparatus according to claim 2, wherein the total area of the hollow fiber filtration membrane of the second filter is not more than に 対 し of the total area of the hollow fiber filtration membrane of the first filter. 4. The hollow fiber membrane has a pore size of 0.01 to 0.45 μm.
The water purification device according to any one of claims 1 to 3, wherein