JPH09187766A - Clarification apparatus for drinking water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly supply clean water by decreasing the frequency of cleaning of a hollow fiber membrane filter and continuing supplying of clean water for a long time. SOLUTION: In a clarification apparatus for clean water wherein the clean water is formed by filtering raw water supplied by driving a pump 1 by means of a hollow fiber membrane filter 4 and a cleaning means for cleaning the hollow fiber membrane filter 4 is installed, and bleed-off circuit 20 provided with a circulation path 18 for circulating a part of the raw water sucked by means of a pump 1 from the ejection side of the pump 1 to the suction side and a flow rate control valve 19 for controlling the flow rate of the raw water flowing this circulation path 18 is installed. When filtering performance of the hollow fiber membrane filter 4 is decreased as impurities in the raw water are stuck on the surface of the hollow fiber membrane, pressure of the raw water supplied to the hollow fiber membrane filter 4 side is elevated by downing the divergence of the flow rate control valve 19 and the amt. of supplying is increased to recover the amt. of formation of clean water and to decrease the frequency of cleaning of the hollow fiber membrane filter 4.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a drinking water purifying apparatus.

[0002]

2. Description of the Related Art In recent years, various drinking water purification devices have been developed for purifying polluted water (hereinafter referred to as raw water) so that it can be used as drinking water in an emergency such as an earthquake. . Among such drinking water purifiers,
A filter device using a hollow fiber membrane filter is known as a filter device for filtering raw water. The hollow fiber membrane filter is
Capable of capturing fine particles of about 0.1 μm,
It is possible to surely remove bacteria such as Escherichia coli having a size of several μm.

A drinking water purifying apparatus using a hollow fiber membrane filter is equipped with a cleaning means for backflowing filtered water or performing air bubbling, and the surface of each hollow fiber membrane in the hollow fiber membrane filter contains raw water. When contaminants or the like are attached and the filtration performance is lowered, the hollow fiber membrane filter is washed by the washing means to restore the filtration performance.

[0004]

However, it takes several minutes to 10 minutes per washing to wash the hollow fiber membrane filter, and during this washing, the filtration of the raw water is temporarily interrupted. The supply of purified water generated by filtering the water is also temporarily interrupted. Therefore, when the hollow fiber membrane filter is frequently washed, it is not possible to sufficiently meet the demand for quick supply of purified water.

[0005]

According to the first aspect of the present invention,
A pump driven by an electric motor, a raw water supply pipe through which raw water sucked by this pump flows, a hollow fiber membrane filter connected to the discharge side end of this raw water supply pipe, and a filtration with this hollow fiber membrane filter. In a drinking water purifying apparatus including a purified water pipe through which the purified water flows and a cleaning unit that cleans the hollow fiber membrane filter, a part of the raw water sucked by the pump is sucked from the discharge side of the pump. A bleed-off circuit is provided, which includes a return passage for returning the flow to the return passage and a flow control valve for controlling the flow rate of the raw water flowing in the return passage. When producing purified water using such a purifying device for drinking water, first, the opening of the flow control valve is set to a reflux amount suitable for the filtration amount of the hollow fiber membrane filter, and the pump is set. Start driving. When the raw water is filtered by the hollow fiber membrane filter and foreign matter in the raw water adheres to the surface of the hollow fiber membrane to lower the filtration performance and reduce the amount of purified water produced, the flow control valve By reducing the opening, the amount of raw water recirculated through the recirculation passage is reduced, the water pressure of the raw water supplied to the hollow fiber membrane filter side is increased, and the amount of the raw water supplied is increased, resulting in the purified water produced. Restore the amount. Continue to produce purified water,
When the amount of purified water generated by the contamination of raw water further adhering to the surface of the hollow fiber membrane decreases again, the amount of purified water generated is recovered again by further narrowing the opening of the flow control valve. Let In this way, when the amount of purified water produced decreases, the operation of gradually narrowing the opening of the flow control valve to recover the amount of purified water produced is repeated, and the amount of produced purified water decreases to a prescribed amount. At the same time, after the water pressure on the hollow fiber membrane filter side reaches a predetermined pressure, the hollow fiber membrane filter is washed by the washing means. In this way, if the impurities in the raw water adhere to the surface of the hollow fiber membrane and the amount of purified water produced decreases, it is not necessary to immediately wash the hollow fiber membrane filter, and the initial raw water set amount is substantially The water can be uniformly supplied for a long time, and therefore, the purified water can be continuously supplied for a long time in the initial setting state.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the overall structure of the drinking water purifying apparatus of the present invention. First, a pump 1 driven by an electric motor (not shown) is provided, and a raw water supply pipe 2 is connected to the pump 1. This raw water supply pipe 2 is a pipe through which the raw water sucked by the pump 1 flows, and a filter 3 is attached to the suction side end of the raw water, and a plurality of hollow fiber membrane filters 4 are attached to the discharge side end. The stored filter case 5 is connected.

In the hollow fiber membrane filter 4, a large number of hollow fiber membranes 4a in which a large number of slit-shaped holes are formed in the wall surface of a macaroni-shaped hollow fiber having a central hole at the center are provided around a core body (not shown). The water is passed through the slit-shaped holes of the hollow fiber membrane 4a to pass from the outer peripheral surface of the hollow fiber membrane 4a to the hollow fiber membrane 4a.
When it reaches the center hole, it has the ability to block passage of bacteria and contaminants of approximately 0.1 μm or more. As shown in FIG. 2, the inside of the filter case 5 is vertically divided by a partition plate 7 in which an insertion hole 6 for inserting the hollow fiber membrane filter 4 is formed, and a lower portion is a space for raw water to which raw water is supplied. 8, and the upper part is a water purification space 9 in which purified water generated by filtering raw water with the hollow fiber membrane filter 4 is collected.

The filter case 5 has three connection ports 10a, 10b, 10c communicating with the raw water space 8.
And one connection port 10d communicating with the water purification space 9 are formed. The discharge side end of the raw water supply pipe 2 is connected to the first connection port 10a, and the second connection port 10b.
An air supply pipe 12 having a blower 11 connected to one end
The other end is connected, and the third connection port 10c is connected to a discharge pipe 13 for discharging raw water and air that have overflowed at the time of bubbling in backwashing. Fourth connection port 10d
A water purification pipe 14 for draining the generated purified water is connected to the.

From the middle of the raw water supply pipe 2, when the hollow fiber membrane filter 4 is washed by a washing means which will be described later, the water in the raw water space 8 is removed together with the impurities separated from the surface of the hollow fiber membrane 4a. A cleaning drain pipe 15 for draining is branched. Further, an air supply pipe 17 having a compressor 16 connected to one end thereof is connected in the middle of the water purification pipe 14.

The raw water supply pipe 2 is provided with the pump 1
A bypass passage 18 which is a return passage for returning a part of the raw water sucked by the pump 1 to the suction side of the pump 1 is provided to connect the discharge side and the suction side of the pump 1 to each other. A manual needle valve 19 which is a flow rate control valve for controlling the flow rate of the raw water flowing through the bypass passage 18 is provided in the middle of the bypass passage 18. The bypass passage 18 and the needle valve 19 form a bleed-off circuit 20.

Here, the cleaning means is the hollow fiber membrane 4
The foreign matter adhering to the surface of a is peeled off. The blower 11, the air supply pipe 12, the compressor 16, the air supply pipe 17, and the air supply pipe 1 are removed.
It is formed by various valves and the like arranged in the middle of Nos. 2 and 17.

Next, each of the pipes 2, 15 and
Various parts arranged in the middle of 12, 13, 14, and 17 will be described. A pressure gauge 21, a manual needle valve 22, and a motor driven valve 23 are arranged in the middle of the raw water supply pipe 2. A motor-driven valve 24 is arranged in the middle of the cleaning drain pipe 15. An air flow meter 25, a solenoid valve 26, and a check valve 27 are arranged in the middle of the air supply pipe 12. A motor-driven valve 28 is arranged in the middle of the discharge pipe 13. A pressure gauge 29, a manual needle valve 30, an activated carbon filter 31, a motor-driven valve 32, a water flow meter 33, and a manual ball valve 34 are arranged in the middle of the water purification pipe 14. A filter regulator 35, an air filter 36, a solenoid valve 37, and a check valve 38 are arranged in the middle of the air supply pipe 17.

In the case of producing purified water by using this drinking water purifying apparatus with such a constitution, first, the opening degree of the needle valve 19 is adjusted to the reflux amount suitable for the filtration amount of the hollow fiber membrane filter 4. Then, the operation of the pump 1 is started. When the operation of the pump 1 is started, the raw water sucked by the pump 1 flows through the raw water supply pipe 2 and is supplied into the raw water space 8 of the filter case 5, and a part of the raw water is pumped through the bypass passage 18. 1 is returned to the suction side. The raw water supplied into the raw water space 8 is purified by the hollow fiber membrane filter 4 from blocking the inflow of bacteria, contaminants, etc., and this purified water is collected in the clean water space 9 of the filter case 5 and then discharged for purification. Water is supplied by flowing through the pipe 14. As for the purified water flowing through the purified water drain pipe 14, the dissolved matter is adsorbed by the activated carbon filter 31 on the way, and odorous substances and other dissolved matters are removed. Since the pump 1 is driven by an electric motor, low noise and low vibration are achieved.

When the purified water is continuously produced in this manner, contaminants are attached to the surface of the hollow fiber membrane 4a to lower the filtration performance of the hollow fiber membrane filter 4, and as shown in FIG. The amount produced decreases gradually.

When the amount of purified water produced falls to a predetermined amount, the opening of the needle valve 19 of the bleed-off circuit 20 is narrowed down. Then, the amount of raw water recirculated through the bypass passage 18 is reduced, the water pressure of the raw water supplied to the hollow fiber membrane filter 4 is increased, and the amount thereof is increased. Continuing to generate purified water with the opening of the needle valve 19 kept as it is, contaminants further adhere to the surface of the hollow fiber membrane 4a, so that the filtration performance of the hollow fiber membrane filter 4 deteriorates, as shown in FIG. 3B. Thus, the amount of purified water produced gradually decreases.

When the amount of purified water produced again falls to a predetermined amount, the opening of the needle valve 19 of the bleed-off circuit 20 is further narrowed. Then, the raw water recirculated through the bypass passage 18 is further reduced, the water pressure of the raw water supplied to the hollow fiber membrane filter 4 side is further increased, the amount thereof is further increased, and the production amount of purified water is recovered again.
Continuing to generate purified water with the opening degree of the needle valve 19 kept as it is, foreign matter further adheres to the surface of the hollow fiber membrane 4a, whereby the filtration performance of the hollow fiber membrane filter 4 deteriorates, and C of FIG. As shown in, the amount of purified water produced gradually decreases. When the generated amount of purified water drops to a predetermined amount and reaches a predetermined pressure, the hollow fiber membrane filter 4 is washed by the washing means, and after this washing is completed, the needle valve 19 of the bleed-off circuit 20 Return the opening to the initial state and restart the production of purified water.

Therefore, compared with the case where the bleed-off circuit 20 is not provided, the frequency of cleaning the hollow fiber membrane filter 4 becomes, for example, 1/3, and purified water can be continuously generated for a long time, and the purified water can be continuously produced. It can fully meet the demand for quick supply.

Next, the cleaning of the hollow fiber membrane filter 4 will be described. During this cleaning, the valves 23 and 32 are closed and the solenoid valve 37 is opened to open the compressor 16
Drive. By driving the compressor 16, high-pressure air is supplied from the fourth connection port 10d into the water purification space 9,
The purified water accumulated in the water purification space 9 flows from the center hole of the hollow fiber membrane 4a toward the outer periphery in the opposite direction to that at the time of filtration, and the contaminants adhering to the surface of the hollow fiber membrane 4a are peeled off. Then, the drive of the compressor 16 is stopped, the electromagnetic valves 26 and 28 are opened, and the blower 11 is driven. Air is supplied from the second connection port 10b into the raw water space 8 by driving the blower 11, air bubbling is performed on the raw water that has accumulated in the raw water space 8, and air bubbles are applied to the surface of the hollow fiber membrane 4a. The peeling of adhering impurities is promoted. After the air bubbling is performed, the drive of the blower 11 is stopped and the valve 2
By opening the valve 4, the water in the raw water space 8 is drained from the cleaning drain pipe 15 together with the contaminants separated from the surface of the hollow fiber membrane 4a. The air supplied by the blower 11 and the compressor 16 during this cleaning is discharged through the discharge pipe 13.

In the present embodiment, when the amount of purified water produced falls to a predetermined amount, an operator who confirms the amount of purified water may manually adjust the opening of the needle valve 19 of the bleed-off circuit 20. Although described as an example, the amount of purified water generated may be confirmed by a sensor, and the opening degree of the needle valve 19 may be automatically adjusted based on the confirmation result.

[0020]

EFFECTS OF THE INVENTION According to the present invention, when the amount of purified water produced decreases due to the contaminants in the raw water adhering to the surface of the hollow fiber membrane and the filtration performance of the hollow fiber membrane filter is reduced,
By reducing the opening of the flow control valve to reduce the amount of raw water recirculated through the recirculation passage, increasing the water pressure of the raw water supplied to the hollow fiber membrane filter side and increasing the amount of raw water supplied. The amount of purified water produced can be recovered, and when the amount of produced purified water decreases, the operation of reducing the opening of the flow control valve to recover the amount of purified water produced will be repeated. The cleaning frequency of the hollow fiber membrane filter by the means can be reduced, whereby the purified water can be continuously supplied for a long time, and it is possible to meet the demand for the rapid supply of the purified water.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional side view showing a structure of a filter case and a structure for housing a hollow fiber membrane filter in the filter case.

FIG. 3 is a graph showing the relationship between the valve opening of the bleed-off circuit and the amount of purified water produced.

[Explanation of symbols]

 1 Pump 2 Raw Water Supply Pipe 4 Hollow Fiber Membrane Filter 14 Water Purification Pipe 18 Reflux Passage 19 Flow Control Valve 20 Bleed-off Circuit

Claims (1)

[Claims] 1. A pump driven by an electric motor, a raw water supply pipe through which raw water sucked by this pump flows, a hollow fiber membrane filter connected to the discharge side end of this raw water supply pipe, and this hollow In a drinking water purification device comprising a water purification pipe through which purified water filtered by a fiber membrane filter flows, and a cleaning means for cleaning the hollow fiber membrane filter, part of the raw water sucked by the pump is A drinking water purifying device comprising a bleed-off circuit provided with a return passage for returning from a discharge side to a suction side and a flow control valve for controlling a flow rate of raw water flowing in the return passage.