JPH0780446A - Water purifier - Google Patents

Abstract

PURPOSE:To obtain a water purifier capable of removing a compd. having a problem from the aspect of safety or comfortableness by limiting an adsorbent. CONSTITUTION:A definite flow valve 13 and a switch 14 are disposed between a first water purifying tank 2 packed with a cation exchange resin 5 and activated carbon 3 and a second water purifying tank 10 packed with porous hollow fiber membranes 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water purifier for obtaining safe and delicious water. More specifically, it relates to a water purifier capable of removing a compound having a problem in safety and comfort by limiting an adsorbent.

[0002]

2. Description of the Related Art As a water purifier, an activated carbon water purifier whose main purpose is to remove residual chlorine contained in tap water was released and used several years ago, but it was not used for a long time according to a survey by the Ministry of Health and Welfare. In this case, it became clear that various bacteria were generated in the activated carbon, which was not preferable.

In order to suppress the outflow of these germs, a water purifier using membrane filtration such as a porous hollow fiber membrane has been put on the market, and recently this type has become the mainstream.

Although not quantitatively large, water purifiers using reverse osmosis membranes and water purifiers using natural stones, ceramics, etc. as filter media are also on the market.

[0005]

Problems to be Solved by the Invention In the above-mentioned water purifier, which is not subjected to membrane filtration such as a porous hollow fiber membrane, miscellaneous bacteria will proliferate in the initial flow of tap water unless it is used for a long time. There was a problem that it would be leaked.

In order to solve such a problem, a water purifier for performing microfiltration with a porous hollow fiber membrane or a flat membrane and a water purifier having antibacterial properties by a method of impregnating activated carbon with silver have been developed. , Is now on the market.

[0007] Activated carbon impregnated with silver is slightly unstable because the antibacterial property differs depending on the amount of silver to be eluted, and it is not good even if a large amount of silver flows out. The method by membrane filtration has sufficient performance to remove various bacteria and the like if there is no mistake in the method of use and fixation of the membrane.

[0008] If activated carbon is used, it is possible to remove trihalomethane, pesticides and other organic substances which may be dissolved in a trace amount, depending on the amount and performance of the activated carbon.

However, it is difficult to remove cations of heavy metals such as lead and anions such as nitrate nitrogen and nitrite nitrogen, which are soluble, by activated carbon or membrane filtration, and almost none of them can be removed. It was the current situation.

In order to remove these ions, a water purifier using a reverse osmosis membrane has also been developed, but it removes all minerals from the viewpoint of the deliciousness of drinking water, which makes the water tasteless and safe. There was a problem in terms of delicious water.

As a water purifier used for a water source having various kinds of impurities, a water purifier in which tap water is housed in a pressure resistant container, activated carbon, and ion-exchange resin are flowed in this order is proposed (Japanese Patent Laid-Open No. 61-61). No. 257,282).

In the water purifier as described above, even if the adsorption limit of the filter is reached, it is difficult to judge the use limit unless there is an extreme change in taste, odor, color or the like. The present inventors have arrived at the present invention as a result of studies to obtain safe and delicious water in view of such a situation.

[0013]

That is, the gist of the present invention is a water purifier comprising a first water purification tank comprising a cation exchange resin and activated carbon and a second water purification tank comprising a porous hollow fiber membrane. A constant flow valve and a pressure switch are provided between the first water purification tank and the second water purification tank.

The present invention requires a combination of a cation exchange resin, activated carbon and a porous hollow fiber membrane. If only cation-exchange resin or activated carbon is used, germs will flow into the initial flow from the water purifier when germs are generated, which is not preferable from a safety standpoint.

Further, there is a problem that it is difficult to remove soluble cations of heavy metals such as lead with only activated carbon and porous hollow fiber membranes. Further, when only the cation exchange resin and the porous hollow fiber membrane are used, trihalomethane, pesticides and the like cannot be adsorbed and residual chlorine cannot be sufficiently removed, which is not preferable.

Among the cation exchange resin, activated carbon and porous hollow fiber membrane of the present invention, the porous hollow fiber membrane in the second water purification tank must be present at the final stage of the water purifier. As the ion exchange resin and the activated carbon, the cation exchange resin and the activated carbon may be used in this order, or the activated carbon and the cation exchange resin may be used in this order or a mixture of both may be used. When silver-impregnated activated carbon is used as the antibacterial activated carbon, the exchange capacity of the cation exchange resin decreases due to the outflow of silver. Therefore, the activated carbon is mixed first, and then the type of cation exchange resin and the type of activated carbon and the cation exchange resin are mixed. Is not preferable.

For these reasons, it is preferable to filter the cation exchange resin, the activated carbon and the porous hollow fiber membrane in this order. The cation exchange resin used in the present invention may be either a strongly acidic cation exchange resin or a weakly acidic cation exchange resin as long as it corresponds to the substance to be removed.

When actually used for tap water, there are many heavy metal cations such as lead, which are likely to be eluted as a harmful substance from the lead pipe used for the water distribution pipe, and also dissolved as a neutral salt. Therefore, it is preferable to use a strongly acidic cation exchange resin capable of decomposing and adsorbing a neutral salt.

Strongly acidic cation exchange resins are generally sold as sodium salts, but they are not preferred because sodium may flow out due to ion exchange, and problems such as an increase in blood pressure may occur when used for drinking.

If an acid-type strongly acidic cation exchange resin is used in order to prevent sodium from flowing out, the pH of the effluent becomes 4 or less, which is out of the tap water quality standard and the irritation becomes strong, which is not preferable.

When a strong acid cation exchange resin is used,
It is preferable that the eluted ions improve the taste of water, and the calcium salt type is used, which Japanese people tend to lack in terms of health.
Thus, in order to drink tap water safely and tastyly, it is most preferable to use a calcium salt type strongly acidic cation exchange resin as the cation exchange resin.

The activated carbon used in the present invention is not particularly limited as long as it has the ability to reduce residual chlorine and the ability to adsorb harmful substances such as trihalomethane and pesticides. , Activated carbon such as fibrous or formed charcoal can be used, and the raw material is not particularly limited. Natural product activated carbon such as coconut shell activated carbon, bone charcoal, charcoal activated carbon, pitch activated petroleum coke activated carbon, etc. Etc. can be used. The activation method is also not particularly limited, and steam activation,
An activation method such as chemical activation is used.

When used as a water purifier, the water passing through the activated carbon has a very high passage speed as compared with the usual method of using activated carbon, so that it is preferable that the bulk density is large. It is preferable that the loss is small. Most of the adsorbed substances have a relatively small molecular weight, and in view of cost, steam activated granular coconut husk activated carbon is most preferably used at present.

The activated carbon of the present invention may or may not be impregnated with a heavy metal such as silver in order to impart antibacterial properties, but it is not preferable that a large amount of heavy metal is eluted. Those having antibacterial properties are relatively preferably used.

In the present invention, a porous hollow fiber membrane must be used. The use of a porous flat membrane is not preferable because a sufficient filtration membrane area may not be obtained. The porous hollow fiber membrane of the present invention is not particularly limited as long as minute substances such as bacteria can be removed, and a porous hollow fiber membrane of polyolefin such as polyethylene or polypropylene or polysulfone is used. These porous hollow fiber membranes are, for example, saponified ethylene-vinyl acetate copolymers (= ethylene-vinyl alcohol-based copolymers) in order to improve water permeability.
It is preferably hydrophilized.

The present invention is a combination of a first water purification tank filled with a cation exchange resin and activated carbon and a second water purification tank containing a porous hollow fiber membrane, and the outflow of the first water purification tank. The water will flow into the second water purification tank. In the present invention, a constant flow valve and a pressure switch are provided between the first water purification tank and the second water purification tank, and the life of the filter body is determined by the cumulative operating time of the pressure switch that can detect that a constant flow rate is flowing. It is something to detect.

When the above-mentioned detection means is arranged on the primary side of the first water purification tank, there is a pressure loss of the cation exchange resin, the activated carbon and a pressure loss of the porous hollow fiber membrane, so that sufficient detection may not be possible. It is not preferable because Regarding the above points, it is preferable to arrange the secondary water tank on the secondary side, but it is not preferable to generate a portion where water is likely to stay after passing through the porous hollow fiber membrane in terms of generation of various bacteria. Although there is a pressure loss due to the porous hollow fiber membrane, it is preferably arranged between the first water purification tank and the second water purification tank. In addition to the cation exchange resin, activated carbon and porous hollow fiber membrane of the present invention, a primary filter, ceramics, natural stone, etc. may be used at the same time.

[0028]

EXAMPLES The present invention will be described in more detail below with reference to examples. [Embodiment 1] FIG. 1 is a sectional view of a water purifier showing an example of the present invention.
It was shown to. The first water purification tank 2 filled with the cation exchange resin 5 and the activated carbon 3 and the second water purification tank 10 accommodating the porous hollow fiber membrane 11 are connected by a water distribution pipe and housed in the outer container 1.

A hydrophilic polyethylene porous hollow fiber membrane 11 was fixed to the second water purification tank 10 with a two-component polyurethane resin, and one end was cut and opened. A resin frame 6 with a nylon mesh of 150 mesh attached from the primary side is installed in the first water purification tank 2, and the cation exchange resin 5
Was charged to 300 ml. Cation exchange resin 5 and activated carbon 3
Resin frame 4 made in the same manner as the resin frame so that
Inserted. Activated carbon 3 was filled on it, and a resin frame 17 prepared in the same manner was inserted so that the activated carbon did not flow out.

The first water purification tank 2 and the second water purification tank 10 are connected by a water distribution pipe, a constant flow valve 13 and a pressure switch 14 are provided in the middle of the water distribution pipe, and an output signal of the pressure switch 14 is displayed and a control unit. At 8, the water flow time at a constant flow rate was integrated to display the life of the water purifier.

As the cation exchange resin 5, a strongly acidic cation exchange resin (Amberlite IR-produced by Organo Corporation) is used.
120B) was used as a calcium salt type by the following method.

1 liter of the above commercially available resin was placed in a glass funnel, and 1.5 liter of 4N hydrochloric acid aqueous solution (about 3 times equivalent of the exchange capacity of the resin, the equivalent number in parentheses below is the exchange capacity of the counterion exchange resin) is 200 ml / Water was passed at a water flow rate of minutes. After that, 10 liters of ion-exchanged water was washed with water at a water flow rate of 200 ml / min, and then 3N sodium hydroxide aqueous solution 2
1 liter (about 3 times equivalent) was flown at a rate of 200 ml / min to give a sodium salt form. Further, it was washed with 10 liters of ion-exchanged water at a water flow rate of 200 ml / min, 1.5 liters of a 4N hydrochloric acid aqueous solution (about 3 times equivalent), and then washed with 10 liters of ion-exchanged water.

1 liter of a 3 mol / l calcium chloride aqueous solution (about 3 times equivalent) was passed through the obtained acid-type strongly acidic cation exchange resin at a water flow rate of 100 ml / min. Then, 10 liters of ion-exchanged water was washed with water at a rate of 200 ml / min. Collect the calcium chloride solution and all the effluent when ion-exchanged water is passed, measure the calcium ion concentration by the chelate titration method (based on the water purification test method), and the amount of calcium trapped in the strongly acidic cation-exchange resin. Was calculated back to find that 1.68 equivalents / l-ion exchange resin was exchanged.

As the activated carbon, Kuraray Coal T-SB48 / 100 manufactured by Kuraray Chemical Co. was used as it was on the market.

Tap water enters through the water inlet 7, passes through the cation exchange resin 5 and the activated carbon 3 in the first water purification tank 2, and passes through the constant flow valve 13 and the pressure switch 14 in the water pipe, The water enters the second water purification tank 10 containing the porous hollow fiber membrane 11, is filtered by the porous hollow fiber membrane 11, and then flows out from the purified water discharge port 9.

The test results of the water purifier thus obtained are shown below. In the test, the water flow rate was set to 4 l / min. The cumulative life of the signal obtained from the pressure switch was 2000 minutes, that is, the cumulative flow rate was 8 m ³ , and was set as the cartridge life.

(1) Residual chlorine removal capacity 2.0 ± 0.2 ppm Residual chlorine-containing water was passed through, and the residual chlorine concentration of the outflow water was measured. The residual chlorine was measured by the o-tolidine method. The residual chlorine concentration in the outflow water after passing 8 m ³ was 0.01 ppm or less.

(2) Sterilizing ability Pseudomonas diminuta IFO
Although 6 liters of water containing 14213 1.7 × 10 ⁷ cells / ml was passed, the number of bacteria in the outflow water was 0 cells / ml.

(3) Lead removal capacity A lead chloride aqueous solution having a lead concentration of 150 ppb was passed through. The lead concentration in the outflow water after passing 8 m ³ was 10 ppb or less.

(4) Removal capacity of trihalomethane A solution prepared by adjusting chloroform to 50 ppb was passed through.
Chloroform concentration of outflow water is 8 ppb when 8 m ³ water is passed.
It was below.

(5) Cartridge life display When the cartridge life display of this apparatus was confirmed using a commercially available stopwatch, the water passage time was 2000 minutes and the cumulative flow rate was 7860 liters.

As described above, the water purifier of the present invention can also remove heavy metal cations such as lead by filling it with a cation exchange resin.

[0043]

As described above, the present invention has a cartridge life detector attached to a water purifier composed of a cation exchange resin, activated carbon and a porous hollow fiber membrane as described above. While removing
It is an epoch-making water purifier that detects the life of the water purifier and allows you to drink safe and delicious water.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a water purifier of the present invention.

[Explanation of symbols]

 1 Water Purifier Outer Container 2 First Water Purification Tank 3 Activated Carbon 4, 6, 12 Resin Frame 5 Cation Exchange Resin 7 Tap Water Inlet 8 Display and Control Section 9 Water Discharge Port 10 Second Water Purification Tank 11 Porous Hollow Fiber Membrane 13 Constant flow valve 14 Pressure switch

Front Page Continuation (72) Inventor Ikuo Igami 2-3-19 Kyobashi, Chuo-ku, Tokyo Inside Mitsubishi Rayon Co., Ltd.

Claims (2)

[Claims] 1. A water purifier comprising a first water purification tank comprising a cation exchange resin and activated carbon and a second water purification tank comprising a porous hollow fiber membrane, wherein the first water purification tank and the second water purification tank are provided. A water purifier characterized in that a constant flow valve and a pressure switch are provided between the two. 2. The water purifier according to claim 1, wherein the cation exchange resin is a calcium salt type.