WO2001085314A1

WO2001085314A1 - Tankless domestic water purifier of reverse osmosis type

Info

Publication number: WO2001085314A1
Application number: PCT/KR2000/000436
Authority: WO
Inventors: No Won Kim; Soon Sik Kim; Je Sung Park; Ki Seop Park
Original assignee: Saehan Industries Incorporation
Priority date: 2000-05-09
Filing date: 2000-05-09
Publication date: 2001-11-15
Also published as: AU5430700A

Abstract

Disclosed is a tankless domestic water purifier of a reverse osmosis type. The tankless domestic water purifier mainly comprises a pretreatment filtration portion, a main filtration portion, and a post-treatment filtration portion. Purified water resulting from the passage through the filtration portions can be obtained at a sufficient amount without being stored in a reservoir tank when an intake valve is opened. The tankless domestic water purifier, from which a sufficient amount of water can be discharged right after being finally filtered, is free from the installation of a reservoir tank and the proliferation of bacteria.

Description

TANKLESS DOMESTIC WATER PURIFIER OF REVERSE OSMOSIS TYPE

TECHNICAL FIELD

The present invention relates to a tankless domestic water purifier of a reverse osmosis type. More specifically, this invention pertains to a water purifier capable of discharging purified water immediately after purifying without storing the water in a reservoir tank.

PRIOR ART

With a great advance in the industrialization, people have enjoyed various modern conveniences while also having suffered from negative side effects.

Representative of the negative side effects are water pollution, whic; is mainly attributed to industrial wastes and domestic sewage, and air pollution produced by gases discharged from many cars, factories, and so on.

Resulting from air pollution, acid rain produces a contamination of water.

Up to now, the contamination of water has become so serious that people cannot safely drink underground water, nor even tap water. Indeed, it can be said that clean water is an essential condition for the survival of animals and plants. To have safer water, many people equip their houses with water purifiers.

Conventional water purifiers take various purification manners. Among them, a purification manner using a reverse osmosis membrane can filter off microscopic matters, such as bacteria and heavy metals. Therefore, it is considered to be the most economical and effective method.

Conventional reverse osmosis-type water purifiers produce water of quality, but suffer from the structural problem of being required to have reservoir tanks in which microorganisms are feasibly proliferated. In addition, this structural problem is true of conventional water purifiers of different purification types, causing a reliability problem in the purified water. Until this invention, no reports were found in which reverse osmosis-type, domestic water purifiers are applied as tankless water purifiers because they cannot produce purified water at a rate great enough to employ no reservoir tanks in their systems. In addition to the water flow limitation that conventional reverse osmosis membranes bear, the noise of the pump makes it difficult to make a water purifier in which a sufficient amount of water can be obtained immediately after being filtered. In the later 1990s, however, there was achieved a sharp improvement in reverse osmosis membrane techniques, which enabled the flow rate of the reverse osmosis membrane to increase from 20 gfd (gallon/day ft²) to 45 gfd or more. Additionally, the improved techniques have a potential to prepare a tankless domestic water purifier of a reverse osmosis type which can be sufficiently operated even at low pressures, in combination with membrane module preparation techniques and post-treatment techniques.

Isolating membrane filters taking advantage of reverse osmosis are largely divided into nanofiltration membrane filters and reverse osmosis membrane filters.

Also, the reverse osmosis membranes can be sub-divided into spiral wound-type polyamide reverse osmosis membranes and hollow fiber-type polyamide reverse osmosis membranes. The spiral wound-type polyamide reverse osmosis

'^• membrane is prepared as follows: on non- woven fabric or fabric cloth is coated a polysulfone or polyether film onto which an aromatic or alicyclic polyamide coating is applied. Then, the combined structure is wound into a spiral wound form from a planar form to give a module which can be applied for the reverse osmosis membrane. The hollow fiber-type reverse osmosis membrane is based on a module which is prepared by coating an aromatic or alicyclic polyamide on hollow fibers made of polysulfones, polyether sulfones or polyacrylonitriles.

Water purifiers using such reverse osmosis membranes are far superior in removal efficiency for metal ions to those using ultrafiltration membranes or micro filters.

DISCLOSURE OF THE INVENTION Reverse osmosis-type domestic water purifiers known thus far, cannot produce so sufficient amounts of purified water as to be suitable for use as tankless water purifiers. Recently developed reverse osmosis membranes are improved in the production rate of purified water, so as to allow the development of a reverse osmosis-type tankless domestic water purifier, in which bacteria are basically prevented from being proliferated.

It is an object of the present invention to provide a reverse osmosis-type tankless domestic water purifier, from which a sufficient amount of water can be discharged right after being finally filtered, free from the installation of a reservoir tank and the proliferation of bacteria.

In accordance with the present invention, there is provided a tankless domestic water purifier of a reverse osmosis type, composed mainly of a pretreatment filtration portion, a main filtration portion, and a post-treatment filtration portion, wherein purified water resulting from the passage through the filtration portions can be obtained at a sufficient amount without being stored in a reservoir tank when an intake valve is opened.

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawing, in which:

FIG. 1 shows a schematic view of an organization of a reverse osmosis- type tankless domestic water purifier in accordance with the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

The application of the preferred embodiment of the present invention is best understood with reference to the accompanying drawing. Referring to Fig.1 , a reverse osmosis-type tankless domestic water purifier in accordance with an embodiment of the present invention is comprised mainly of a pretreatment filtration portion, a main filtration portion and a post-treatment filtration portion. The pretreatment filtration portion comprises a sedimenting filter 4 and a pretreatment carbon filter 6. For the main filtration portion is responsible a reverse osmosis membrane filter or nanofiltration filter 7. In the post-treatment filtration portion, a post-treatment carbon filter 9 plays an important role.

A tap water feed valve 2 is mounted on a tap water feed pipe 3 branched from a tap water pipe 1 , and is designed to supply water to a filtering system and block the flow of water. A pressurization pump 5 is disposed between the sedimenting filter 4 and the pretreatment carbon filter 6. A clean water pipe 12 and a concentrated water pipe 13 are branched from the reverse osmosis membrane filter or the nanofiltration filter 7. Along the clean water pipe 12, purified clean water flows from the main filter to the post-treatment carbon filter 9 through a back water valve 8. On the other hand, the concentrated water pipe 13 provides a conduit for the concentrated water resulting from the reverse osmosis through the main filter, whose discharge rate is controlled by a flow control valve 1 1. The water introduced to the post-treatment filtration portion is further purified through the post-treatment carbon filter 9 and then, discharged through an intake valve 10.

When the tap water feed valve 2 is opened, water flows into the inside of the purifier via the tap water feed pipe 3 from the tap water pipe 1. Then, after passing through the sedimenting filter 4, the water is pressurized by the pressurization pump 5 to pass through the pretreatment carbon filter 6 to the reverse osmosis membrane filter 7 in which fine impurities are filtered off. At this time, the pressurization is carried out at a pressure ranging from 10 to 125 psi. Under this circumstance, purified water is produced at such a sufficient amount that it can be directly discharged through the intake valve 10 without being stored in a reservoir tank.

The pretreatment filtration portion employs a sedimenting filter, such as a metal micro filter or a polypropylene micro filter, and a carbon filter, such as an active carbon granule filter, an active carbon powder filter and an active carbon bar filter. The post-treatment filtration portion comprises an active carbon filter or an Ag-containing carbon filter in combination with UV-disinfection means, a ceramic filter, a polypropylene micro filter, an ultrafiltration membrane filter and/or a magnetizing filter.

Suitable for use in the spiral wound-type reverse osmosis membrane filter is the module which ranges, in effective membrane area, from 10 to 40 ft², in outer diameter, from 1.8 to 4 inches and in length, from 10 to 16 inches. For the hollow fiber type, there is preferably used the module which is 20-50 ft² in effective membrane area, 1.8-4 inch in outer diameter and 10-16 inch in length.

The water filtered in the reverse osmosis membrane filter or nano filtration filter 7 passes through the back water valve 8 along the clean water pipe 12 into the post-treatment carbon filter 9 in which the final purification occurs. The water thus purified is so large in quantity that, whenever it is required, a sufficient amount of the water can be obtained through the intake valve 10 without being stored in a reservoir tank. The water purifier can be designed to choose the module in accordance with necessary amounts of water. The water purifier system as above mentioned is not limited to the purifiers using reverse osmosis membranes, but can be applied for purifiers having ultrafiltration membrane. In the purifier using a reverse osmosis membrane or a nanofiltration membrane, raw water is fed to the pressurization pump 5 at a flow rate of 0.3-12 L per minute.

Meanwhile, the impurity-concentrated water resulting from the reverse osmosis is discharged by way of the flow control valve 11 through the concentrated water pipe 13.

The performance of the module determines whether the reverse osmosis- type water purifier can be used without a reservoir tank or not. The module can be diversely designed in performance depending on various conditions, including physical properties of reverse osmosis membranes, effective membrane areas, driving pressures and the like. Additionally, the water purifier of the present invention may be designed to run with the reverse osmosis pressure exerted by the pressurization pump 5 or only by the water which is fed from the tap water pipe 1 in the absence of the pressurization pump. A better understanding of the present invention may be obtained in light of the following examples which are set forth to illustrate, but are not to be construed to limit the present invention.

EXAMPLE I

On a polyester non-woven fabric 95+5 μ thick, a polysulfone was coated at a thickness of 50 μm to give a support layer. A polyamide membrane resulting from the interfacial polymerization of metaphenylendiamine and trimezoyl chloride was applied onto the support layer. A mesh of polypropylene was interposed between the polyamide membrane and an epoxy-impregnated. polyester tricot and the five laminated layers were integrated by rolling. From the resulting structure which consisted of five membrane layers and was 2.1 m long, a module was prepared which was 2.3 ft in effective membrane area, and 3.5 inch in outer diameter and 12 inch in length.

The module thus prepared was installed in a tankless water purifier shown in Fig. 1 and used to purify tap water. When measured at 25 °C with raw water 500 ppm in concentration being fed at a pressure of 30 psi, the module was determined to be 260 gpd in flow rate and 94.8 % in salt removal rate.

EXAMPLES II TO VII

The reverse osmosis membrane module prepared in Example I was installed in the same tankless water purifier as shown in Fig. 1. The water purifier was measured for flow rate and salt removal rate at 25 °C while raw water with a concentration of 500 ppm was fed at various pressures of 15 psi, 45 psi, 60 psi, 90 psi and 120 psi. The results are shown in Table 1 , below. TABLE 1

Example Driving Recovery Flow Rate Flow Rate Salt Removal Nos. Pressure Rate (%) (gpd) (ml/min) Rate ⁽⁰'

II 15 psi 50 143 476 91.8 πi 45 psi 50 380 999 95.4

IV 60 psi 50 486 1277 96.7

V 90 psi 50 676 1777 96.9

VI 120 psi 50 890 2339 96.6

INDUSTRIAL APPLICABILITY

Water purified in conventional water purifiers, including a reverse osmosis-type and other types, is feasibly contaminated within their reservoir tanks. In contrast, the water purifier of the present invention needs not a reservoir tank and thus, is free from the secondary contamination caused by bacteria. Accordingly, people can drink clean water using the purifier of the present invention whenever necessary.

The present invention has been described in an illustrative manner, and it is to be understood that the terminology used is intended to be in the nature of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, it is to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

Claims

1. A tankless domestic water purifier of a reverse osmosis type, composed mainly of a pretreatment filtration portion, a main filtration portion, and a post- treatment filtration portion, wherein purified water resulting from the passage through the filtration portions can be obtained at a sufficient amount without being stored in a reservoir tank when an intake valve is opened.

2. The purifier as defined in claim 1, wherein the main filtration portion is a reverse osmosis membrane filter.

3. The purifier as defined in claim 1, wherein the main filtration portion is a nanofiltration membrane filter.

4. The purifier as defined in claim 1, wherein the pretreatment filtration portion consists of a sedimenting filter and a pretreatment carbon filter.

5. The purifier as defined in claim 4, further comprising a pressurization pump disposed between the sedimenting filter and the pretreatment carbon filter, said pressurization pump generating a reverse osmosis-driving force.

6. The purifier as defined in claim 5, wherein the pressurization pump exerts a pressure ranging from 10 psi to 125 psi.

7. The purifier as defined in claim 5, wherein the pressurization pump transfer raw water at a rate of 0.3-12 L per minute.

8. The purifier as defined in claim 4, wherein the sedimenting filter and the pretreatment carbon filter have no pressurization means therebetween and are fed with raw water directly from a tap water pipe, the water pressure exerted from the tap water pipe serving as a reverse osmosis-driving force. •

9. The purifier as defined in claim 1, further comprising a back water valve on a clean water pipe between the main filtration portion and the post- treatment filtration portion, said back water valve acting to prevent the counter current of the water fed from the main filtration portion to post-treatment filtration portion.

10. The purifier as defined in claim 1, further comprising a flow .control valve on a concentrated water pipe branched from the reverse osmosis membrane filter, said flow control valve acting to discharge impurity-concentrated water resulting from the filtration.

11. The purifier as defined in claim 2, wherein the reverse osmosis membrane filter consists of at least one spiral wound type module, the module having an effective membrane area of 10-40 ft², an outer diameter of 1.8-4 inches and a length of 10- 16 inches.

12. The purifier as defined in claim 2, wherein the reverse osmosis membrane filter consists of at least one hollow fiber-type module, the module having an effective membrane area of 20-50 ft², an outer diameter of 1.8-4 inches and a length of 10- 16 inches.