JPH07155749A - Water purifier - Google Patents

Abstract

PURPOSE:To provide a water purifier enabling to remove a compound causing damage to the safety and taste by specifying an adsorbent. CONSTITUTION:In this water purifier, a first water purifying tank 2 filled with a cation exchange resin 5 and active carbon 3, and a second water purifying tank 11 formed of active carbon and a porous hollow fiber membrane 12 are connected each other with a distributing pipe and an impeller type flow rate sensor 8 is provided in the midway of the distributing pipe and the integrated amount under a flow rate is displayed at a display and control part 9 by the output signal of the flow rate sensor to display the life of the water purifier.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a water purifier for obtaining safe and delicious water. More specifically, the present invention relates to a water purifier capable of removing a compound that causes a loss of safety and deliciousness by limiting an adsorbent.

[0002]

2. Description of the Related Art Activated carbon water purifiers whose main purpose is to remove residual chlorine contained in tap water were released and used several years ago, but according to a survey by the Ministry of Health and Welfare, activated carbon water It was clarified that bacteria were not generated, 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. Recently, a cassette type water purifier in which an activated carbon storage unit and a separation filtration membrane storage unit are further combined with an ion exchange resin storage unit has been proposed (Japanese Utility Model Publication No. 3-7989). Water purifiers using reverse osmosis membranes and water purifiers using natural stones, ceramics, etc. as filter media are also on the market, although the quantity is not large yet.

[0004]

Problems to be Solved by the Invention In the water purifier as described above, a porous hollow fiber membrane or the like which has not been subjected to membrane filtration must be used for a long period of time, and various bacteria will propagate and flow out into the initial stream of tap water. There was a problem that it would end up. In order to solve these problems, a water purifier that performs microfiltration with a porous hollow fiber membrane or a flat membrane and a water purifier with antibacterial properties by methods such as impregnating activated carbon with silver were developed and put on the market. It started to come.

[0005] Activated carbon impregnated with silver has a slightly unstable antibacterial property depending on the amount of eluted silver, and is not good even if a large amount of silver flows out, so that it is slightly unstable in performance. 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. Further, if activated carbon is used, it is possible to remove organic substances that may be dissolved in a trace amount, such as trihalomethane and pesticides, depending on the amount and performance of the activated carbon.

However, cations of heavy metals such as lead, and anions such as nitrate nitrogen and nitrite nitrogen, which are soluble, are difficult to remove by activated carbon or membrane filtration, and have hardly been removed. Was the current situation. A water purifier using a reverse osmosis membrane has been developed to remove these ions, but it removes all minerals from the viewpoint of the deliciousness of drinking water, making the water tasteless and safe and delicious. There was a difficulty in terms of terms.

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

[0008]

Means and Actions for Solving the Problem The gist of the present invention is a water purifier comprising a first water purification tank filled with a cation exchange resin and activated carbon and a second water purification tank comprising activated carbon and a porous hollow fiber membrane. It is in.

The water purifier of the present invention essentially comprises 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. There is also a problem that it is difficult to remove soluble cations of heavy metals such as lead with only activated carbon and a porous hollow fiber membrane. 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 must be present at the final stage of the second water purification tank. The cation exchange resin and the activated carbon in the first water purification tank may be the cation exchange resin and the activated carbon in that order, or the activated carbon and the cation exchange resin may be in that order, or both may be used in combination.

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 used first, and then the type of cation exchange resin and the activated carbon and cation exchange resin Mixing is not preferred. For these reasons, it is preferable to filter the cation exchange resin, the activated carbon and the porous hollow fiber membrane in this order.

As the cation exchange resin used in the present invention, either a strongly acidic cation exchange resin or a weakly acidic cation exchange resin can be used 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 that are likely to be eluted as a harmful substance from the lead pipe used for the water distribution pipe and dissolved as a neutral salt. Since it has high properties, 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 may cause problems such as an increase in blood pressure when used for drinking. If an acid-type strongly acidic cation exchange resin is used 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, and is morphologically powdery, granular, fibrous. , Activated charcoal such as forming charcoal can be used.

The raw materials are not particularly limited, and natural product type activated carbon such as coconut shell activated carbon, bone charcoal, charcoal, etc., pitch type, petroleum coke type, synthetic activated carbon such as firing activated carbon such as resin or rubber. Etc. can be used. The activation method is also not particularly limited, and activation methods such as steam activation and chemical activation are used.

[0016] When used as a water purifier, the water passing through the activated carbon is much faster than the ordinary activated carbon. Therefore, 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 preferable at present.

In the present invention, activated carbon must be filled in the first water purification tank and the second water purification tank. As described above, in the water purifier, the water flow rate inside the activated carbon becomes extremely high. In order to effectively use the performance of activated carbon, it is necessary to use a large amount of activated carbon, and it is necessary to secure a large volume as compared with ion exchange resins and porous hollow fiber membranes.

However, it is difficult to use a large amount of activated carbon in a water purifier of the type currently on the market, and the life may be shortened in consideration of sufficient removal of harmful substances. In addition, the water purifier body also becomes large and it is an obstacle to use it near the sink, so it needs to be stored as compactly as possible, so it has the same volume of water as the ion exchange resin and porous hollow fiber membrane, which has a smaller volume than activated carbon. Each tank must be filled.

The activated carbon used in the first water purification tank and the second water purification tank may be of the same type or of different types, but it is preferable to use activated carbon mainly corresponding to the substance to be adsorbed and removed. The activated carbon of the present invention may 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 polyolefin hollow fiber membrane such as polyethylene and polypropylene, or a polysulfone hollow fiber membrane is used.

These porous hollow fiber membranes are preferably hydrophilized in order to improve water permeability. The present invention has a form in which a first water purification tank filled with a cation exchange resin and activated carbon and a second water purification tank comprising activated carbon and a porous hollow fiber membrane are combined, and the outflow water of the first water purification tank is Second
It will be in the form of flowing into the water purification tank of.

In the present invention, it is preferable to provide a flow sensor or a constant flow valve and a pressure switch between the first water purification tank and the second water purification tank. The life of the filter body is detected by the cumulative operating time of the pressure switch capable of detecting the cumulative filtration flow rate of the flow rate sensor or the constant flow rate.

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, activated carbon and pressure loss of the porous hollow fiber membrane, so that sufficient detection cannot be performed. 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.

The flow of tap water will be described with reference to FIG. Tap water enters from the water inlet 7, the cations in the first water purification tank 2 pass through the exchange resin 5 and the activated carbon 3, and the activated carbon 3 and the porous hollow fiber pass through the flow sensor 8 in the water pipe. The water enters the second water purification tank 11 containing the membrane 12, is filtered by the activated carbon and the porous hollow fiber membrane 12, and then flows out from the water purification outlet 10.

[0025]

EXAMPLES The present invention will be described in more detail below with reference to examples. [Embodiment 1] A sectional view of an embodiment of the present invention is shown in FIG. A second water purification tank 2 filled with cation exchange resin 5, activated carbon 3, activated carbon 3, and a second hollow porous membrane 12
The water purification tank 11 is connected by a water pipe and is housed in the outer container 1.

A hydrophilic polyethylene porous hollow fiber membrane 12 was fixed to the second water purifying tank 11 with a two-component polyurethane resin, one end of which was cut and opened. A resin frame 14 having a nylon mesh of 150 mesh attached was installed so that the activated carbon would not enter the hollow fiber membrane portion, 150 g of activated carbon was filled in the remaining space, and the same manner as the above resin frame was prepared so that the activated carbon would not flow out. The resin frame 15 was inserted.

A resin frame 6 made in the same manner as the above resin frame was installed in the first water purification tank 2 from the primary side, and 300 ml of the cation exchange resin 5 was filled therein. A resin frame 4 manufactured in the same manner as the resin frame was inserted so that the cation exchange resin 5 and the activated carbon 3 were not mixed. Filled with 150 g of activated carbon 3 on it,
The resin frame 13 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 11 were connected by a water distribution pipe, and an impeller-type flow sensor 8 was provided in the middle of the water distribution pipe. The output signal of the flow sensor 8 is integrated by the display and control unit 9 to display the life of the water purifier. As the cation exchange resin 5, a strongly acidic cation exchange resin (Amberlite IR-120B manufactured by Organo Co., Ltd.) made into a calcium salt type by the following method was used.

The above-mentioned commercially available resin 11 was placed in a glass funnel, and 1.5 liter of a 4N hydrochloric acid aqueous solution (about 3 times equivalent of the exchange capacity of the resin; hereinafter, the equivalent number in parentheses 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. Calcium chloride solution and all effluents from ion-exchanged water are collected and the calcium ion concentration is measured 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. When calculated back, 1.92 equivalent / 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. The test results of the water purifier thus obtained are shown below. In the test, the water flow rate was 4 liters / minute. The cartridge life was set at the time when the integrated flow rate of the signal obtained from the flow rate sensor was 8 m ³ .

(1) Residual chlorine removal capacity 2.0 ± 0.2 ppm Residual chlorine-containing water was passed through and the residual chlorine concentration in 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 prepared to have 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) Ability to remove trihalomethanes A solution prepared by adjusting chloroform to 60 ppb was passed through.
The chloroform concentration in the effluent during the passage of 8 m ³ of water was 5 ppb or less.

(5) Cartridge life display When a cartridge life display of this apparatus was confirmed using a commercially available integrating flow meter, it was 79581.

[0037]

[Effect] The present invention is a water purifier composed of a cation exchange resin, activated carbon and a porous hollow fiber membrane, and can be miniaturized while using a large amount of activated carbon while having sufficient adsorption performance. Further, according to the present invention, it is possible to remove dissolved ionic toxic substances which have been difficult to remove up to now, and by attaching a cartridge life detector, even if the toxic substances flow out after the end of their life, they can be drunk without knowing. It is possible to provide a water purifier with improved problems of the water purifier.

[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 Purifier 3 Activated Carbon 4, 6, 13, 14, 15 Resin Frame 5 Cation Exchange Resin 7 Tap Water Inlet 8 Flow Sensor 9 Display and Control Unit 10 Water Discharge Port 11 Second Water Purifier 12 Porous hollow fiber membrane

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Okazaki 4-60 Sunadabashi, Higashi-ku, Nagoya-shi, Aichi Mitsubishi Rayon Co., Ltd. Product Development Laboratory

Claims (3)

[Claims] 1. A water purifier comprising a first water purification tank filled with a cation exchange resin and activated carbon and a second water purification tank comprising activated carbon and a porous hollow fiber membrane. 2. The water purifier according to claim 1, wherein a flow rate sensor or a constant flow valve and a pressure switch are provided between the first water purification tank and the second water purification tank. 3. The water purifier according to claim 1, wherein the cation exchange resin is a calcium salt type.