JP3213618B2 - Two-stage filter cartridge for reverse osmosis purification system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates generally to improvements in water purification systems and reverse osmosis equipment. More particularly, the present invention relates to an improved filter for a reverse osmosis purification unit that incorporates a number of filter stages in a compact, integral cartridge form that can be easily and periodically installed and replaced when needed. Regarding the cartridge.

[0002]

BACKGROUND OF THE INVENTION Reverse osmosis water purification systems are generally well known in the art for producing relatively purified water supplies for use in drinking, cooking, etc. Such purification systems generally include a reverse osmosis unit having a reverse osmosis membrane, which is provided with an incoming tap in the presence of appropriate flow and pressure.
g tap) or feed water is separated into a purified water supply and a relatively unpurified water supply or reject water supply. In particular, the reverse osmosis membrane removes particulates and a wide range of solute solids and other contaminants from a portion of the feedwater to create a purified feedwater and concentrates these contaminants in the remainder of the feedwater; This serves to create a reject water supply, sometimes referred to as brine, which is drained through a suitable drain. Purified water supply is usually
It is collected for storage in a suitable location in a suitable reservoir and so that it can be dispensed at any time, such as through a water valve. In this regard, the available reverse osmosis units may be designed to use compressed air to deliver purified water from a reservoir, as described, for example, in US Pat. No. 4,834,873. Otherwise, the system may be designed to use feedwater pressure to deliver purified water from a reservoir, as described, for example, in US Pat. No. 4,776,952.

[0003] Reverse osmosis membranes have been made from a variety of materials that are known to provide a variety of performance efficiencies and rates of purified water production. However, in many reverse osmosis systems, the choice of membrane material is determined not only by performance efficiency, but also by the chemical and bacteriological composition of the feedwater in the local water supply. For example, so-called thin films or thin film-like composite membranes are commonly used because of their relatively high operating efficiency and substantially no degradation in the presence of certain bacterial organisms that may be present in the feed water. Preferred. This relatively high operating efficiency is obtained with a very compact membrane cartridge having a large membrane surface area.
However, such thin film-like membranes can be used in the presence of oxidants, such as chlorine and / or its compounds, which are often added to local water supplies to control the growth of certain chemicals, especially bacteria or other organisms. It is known to degrade very quickly. Therefore, in the presence of chlorine in the feed water, less efficient membrane materials such as cellulose acetate are usually used to provide acceptable operating life for the membrane, but the production of purified water It is known that it slows down and is relatively susceptible to bacteria. As a variant, some systems use an activated carbon pre-filter upstream of a thin film membrane to remove chlorine from the feed water before performing the reverse osmosis treatment. This latter method can prevent premature failure of the thin film-like membrane, but requires additional filter housing and filter element construction, thus increasing the overall size and increasing the cost of the reverse osmosis system. Would.

[0004]

The present invention overcomes the problems and disadvantages associated with the prior art by providing an improved filter cartridge for a reverse osmosis system.
The filter cartridge contains a thin filter-type compact membrane in combination with a pre-filter stage. This pre-filter stage protects the membrane from contact with harmful components in the local water supply that the membrane would contact without the pre-filter stage.

[0005]

SUMMARY OF THE INVENTION In accordance with the present invention, there is provided an improved filter cartridge for use in a reverse osmosis system, wherein the filter cartridge is incorporated into a single unit in which two filter stages can be easily replaced. It is. The cartridge has a first filter stage with filter media for removing contaminants from an incoming feed or incoming tap, and a second filter stage having a reverse osmosis membrane. The first stage filter media is used in the absence of this filter media so that so-called thin films or thin film-like composite membranes can be used without paying attention to certain contaminants present in the local water supply. Is designed to remove contaminants potentially harmful to reverse osmosis membranes.

[0006] In a preferred form, the two-stage filter cartridge is relatively easily and quickly dropped or slip-fitted into a complementary reverse osmosis unit housing. As is well known in the art, a reverse osmosis unit is installed in a water purification system to receive incoming feedwater and to concentrate the feedwater with a relatively purified feedwater and contaminants that have been removed. And selectively unpurified or rejected water.

The two-stage filter cartridge has first and second stages supported around a common central support tube for continuously passing incoming water. More specifically, the first filter stage has a generally cylindrical canister mounted around a support tube, the canister defining ends with holes for the passage of feed water. A filter media is contained within the canister, the filter media being selected to attract, remove, or react with one or more target contaminants from the feedwater. As an example, it may consist of activated carbon designed to remove chlorine and its compounds from chlorinated feed water. Alternatively, other types of filter media can be used and / or combined with other types of filter media, such as the redox media described in U.S. Pat. No. 4,642,192.

The treated feed leaves the canister of the first filter stage and then passes through a second stage consisting of a reverse osmosis membrane. The membrane is formed by winding a thin film-like membrane to form an elongated but compact tubular structure, which fits around the central support tube at the downstream end of the first filter stage. The feedwater flows into one axial end of the reverse osmosis membrane to properly separate the purified and rejected feedwaters when the proper system pressure is maintained. Reject water exits the membrane at the other axial end of the membrane, and purified water passes radially inward through the membrane layer and into the interior of the support tube through the flow port of the support tube. The purified water is then fluidly connected from the support tube to a suitable storage reservoir and / or to a water supply valve for dispensing.

In accordance with one aspect of the present invention, for the purpose of facilitating regular removal and replacement of cartridges,
Purified water and rejected water are flushed to a common end of the filter cartridge for exiting the housing of the reverse osmosis unit. In this regard, in a preferred form, the purified water flows through a central support tube that extends through the first stage canister to a purified water outlet at one end of the housing. Reject water is also flowed through an overflow conduit that extends through the support tube to a reject water outlet located at the same end of the housing. To isolate purified water and rejected water from each other and to allow the filter cartridge to be easily slid into the reverse osmosis housing with the support tube and overflow conduit connected to the purified water outlet and the rejected water outlet, respectively. Suitable sealing means such as an O-ring seal are provided.

Other features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the exemplary drawings, the water purification system, generally designated 10 in FIG. 1, has a reverse osmosis unit 12 with an improved two-stage filter cartridge 14 (see FIGS. 2 and 3). . This two-stage filter cartridge 1
4 has a reverse osmosis membrane of compact and economical design, which isolates and protects the membrane from contact with incoming taps or selected contaminants which may be present in the feed water. Combined with a pre-filter for.

The two-stage filter cartridge 14 of the present invention
Is a Filmtech company in Minneapolis, Minnesota.
ek Corp.) and U.S.A. in San Diego, California.
Compact and economical as well as very efficient, such as membranes sold by Fluid Systems, Inc., a division or section of UOP, Inc. A so-called thin film or a reverse osmosis membrane made of a composite thin film is advantageously used. This thin film-like membrane is used in combination with a pre-filter. This pre-filter prevents the membrane from prematurely degrading by contact with certain contaminants present in many water supplies, such as chlorine and / or chlorine compounds, which are added to avoid bacterial growth. Protect. This combination filter structure is advantageously incorporated into a single unit. The unit is easily slip-fitted into the reverse osmosis unit housing 16 to provide
It can be quickly and easily installed and / or removed for replacement.

The reverse osmosis water purification system 10 (see FIG. 1)
The system is generally conventional in the art, including the reverse osmosis unit 12 coupled to receive incoming feed water 18. Generally speaking, reverse osmosis unit 12 functions in the presence of suitable fluid pressure to create a relatively purified water supply for use in drinking, cooking, and the like. This purified feedwater is created by removing particles, certain solute contaminants, and these removed components are concentrated in the reject or brine feedwater. Purified water supply
It is typically connected through a suitable purified water conduit 20 so as to flow to a reservoir 22 and be stored therein. Conversely, the reject or brine feed is usually drained into drain line 2 so as to flow to the appropriate waste or drain site.
4 and the like. Purification water in the reservoir
It can be used for subdivision, and is used when the water supply valve 26 or the like is opened. In this regard, the reservoir 22
When the water supply valve 26 is open, it may have pneumatic or hydraulic pressure means for delivering purified water to the water supply valve. This is all done in a manner well known in the prior art and is described, for example, in U.S. Pat. No. 4,834,873 and U.S. Pat. No. 4,776,952, which are incorporated herein by reference.

As shown in FIGS. 2 and 3, reverse osmosis unit 12 has an upwardly open, generally cylindrical housing adapted to receive a two-stage filter cartridge 14 embodying the novel features of the present invention. Sixteen. Housing 16 has mounting means near its open upper end, such as externally formed threads 28, for quick and convenient releasable connection to upper cap 30.
The upper cap 30 is suitably connected to various conduits of the purification system, as described in more detail below. As shown, the cap 30 has a downwardly projecting cylindrical flange 31 with internal threads that allow the housing 16 to be received and connected thereto. However,
It will be appreciated that alternative removable connection structures may be used for housing 16 and cap 30.

The two-stage filter cartridge 14 is designed to be easily slip-fitted and mounted within the housing 16 of the reverse osmosis unit 12. Then, when the housing 16 is secured to the cap 30, the incoming feedwater in the feedwater conduit 18 is constrained to flow continuously through the two filter stages, as described below, to create a purified feedwater. You.

More specifically, the reverse osmosis unit 12
The upper cap 30 has an inlet port 34 to which the feedwater conduit 18 is suitably connected (see FIGS. 2 and 3). During operation of the system, feed water flows through inlet port 34 into an annular inlet chamber 36 cooperatively defined by cap 30 and the upper end of filter cartridge 14. A substantially cylindrical filter canister 3 for performing the first filter stage
8 is formed at the upper end of the cartridge, and this filter canister is open upward to receive the supply water in the inlet chamber 36. One or more sealing members, such as O-rings 39, are compression-fit between the inside of the housing 16 and the outside of the upper end of the canister to prevent feedwater leakage around the outside of the canister. is there.

The filter canister 38 has a cup-like shape as a whole and has a lower end wall 40. A central opening 41 is formed in this end wall 40 so that a central support tube 42, which forms the main support structure connecting the two filter stages together in a single unit, is relatively snugly fitted. Can be accepted by. If desired, an adhesive may be used to secure the canister to the support tube. The support tube 42 has a non-perforated upper end region that extends substantially concentrically within the canister and cooperates with the canister to define a cylindrical filter cavity 44 having a generally annular cross section. The upper adapter fitting 46 has a lower plug that fits within the upper end of the support tube 42 and further includes an annular flange 48 that extends radially outwardly to make tight contact with the inner wall surface of the canister 38.

The flange 48 of the joint 46 has a number of flow ports 50 that allow feed water to flow downwardly from the inlet chamber 36 to the filter cavity 44. Selected filter media 52 is contained within filter cavity 44. The filter media is selected to attract, remove, or react with one or more target contaminants from the feed water, in addition to filtering the particles according to the structural characteristics of the filter media. . In one preferred embodiment of the present invention, activated carbon is used as a filter media for removing chlorine and its compounds from feed water.
In alternative embodiments, other filter media and / or U.S. Pat.
The combination can be used, such as the redox media described in US Pat. No. 642,192.

The second filter stage of the two-stage cartridge is constituted by a reverse osmosis membrane 54 attached to the central support tube 42 just below the canister 38. In this regard, the lower end wall 40 of the canister 38 has a plurality of flow ports 5 through which the treated feedwater passes downwardly to the reverse osmosis membrane 54.
6. A sealing sleeve 57 is conveniently mounted around the junction of the canister 38 and the membrane 54 to constrain the feed water flow into the membrane toward the end. In this regard, as is well known in the art, reverse osmosis membrane 54 comprises a large number of membrane layers wound around support tube 42 into an open-ended cylindrical shape. Referring to the illustrated membrane 54, this membrane is conveniently made from a so-called thin film or thin film-like composite material that is compactly wound but provides a large overall surface area in contact with the feed water. During operation of the system, maintaining a suitable fluid pressure provides a relatively purified supply of water by radial migration, and ultimately through a series of ports 58 in the lower end region of the support tube 42. Pass inward. The reject or brine feed collects contaminants that adhere between the membrane layers and drains from the lower end of the membrane 54.

According to one major feature of the present invention, the filter media 52 in the canister 38 is selected to protect the reverse osmosis membrane 54. More specifically, certain membrane materials, such as thin film materials, are subject to rapid degradation,
It is known that premature failure occurs upon contact with certain chemicals that may be present in the feed water. As an example, chlorine is often used as an additive in water systems to limit bacterial growth, but this chemical causes rapid degradation of thin film-like membranes. Thus, the filter media 52 in the canister 38 may be selected to remove chlorine from the feed water, thereby allowing the use of thin film-like membranes. In this regard, thin film-like membranes are desirable because thin film-like membranes have a relatively high efficiency of producing purified water at relatively high rates.

In accordance with another aspect of the present invention, both purified and rejected water is directed to the top of reverse osmosis unit 12 for discharge through upper cap 30. According to this structure, the housing 16 can be formed as a simple upward-opening cylindrical body which can be fitted with the cartridge 14 slipped down. Thus, the cartridge 14 can be quickly and easily installed and replaced as needed without paying attention to complicated piping equipment and the like.

More specifically, with continued reference to FIGS. 2 and 3, a lower adapter fitting 59 fits over the lower end of the central support tube 42 to prevent mixing of the purified and reject water. ing. One or more spacer legs 60 may be provided on the joint 59 to maintain a suitable spacing between the membrane 54 and the lower end of the housing 16. The purified water produced in the support tube 42 is
Through and upwards, and further through the adapter fitting 46 at the upper end of the canister 38. The upper adapter joint 46 has a tubular upper extension 46 ', which is
0 protrudes into an outlet fitting 62 mounted therein. The lumen 64 of the outlet fitting 62 defines a tubular outlet chamber 66 surrounding a segment of the extension 46 'and a suitable outlet port 6
8 allows purified water to flow into this outlet chamber 66, which is then connected to the purified water conduit 20 through the cap 30 for connection to the purified water outlet port 70 of the joint 62. I have.

The reject water at the lower end of the reverse osmosis membrane 54
It flows freely through the overflow conduit 72. This overflow conduit 72
Is supported by an adapter fitting 59 at the lower end of the support tube 42, which mounts the overflow conduit concentrically within the support tube 42 to the upper end connection with the adapter extension 46 '. Reject water further flows through a reject outlet port 74 of outlet fitting 62, which is suitably connected to drain conduit 24.

Thus, the two-stage filter cartridge is
Provided is an integrated structure that can be quickly and easily dropped and mounted in the reverse osmosis housing 16. The cartridge performs a combined filtration reverse osmosis action, which can be adjusted to allow the use of special membrane materials in an otherwise hostile environment. It will be apparent to those skilled in the art that various modifications and improvements can be made to the two-stage filter cartridge of the present invention.
Accordingly, the invention is not limited by the above description and the accompanying drawings, except as set forth in the claims.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an exemplary reverse osmosis water purification system.

FIG. 2 is an exploded perspective view showing components of a reverse osmosis unit used in the system of FIG. 1, which has an improved two-stage filter cartridge embodying the novel features of the present invention.

FIG. 3 is a partial vertical sectional view showing the reverse osmosis unit in an assembled form.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Water purification system 12 Reverse osmosis unit 14 Two-stage filter cartridge 16 Housing for reverse osmosis unit 20 Purified water conduit 22 Reservoir 24 Drain conduit 26 Water supply valve 30 Upper cap

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B01D 61/00-65/10 C02F 1/44

Claims (5)

(57) [Claims] 1. A reverse osmosis unit for a purification system, comprising: a unit housing formed in a substantially cylindrical body having an open end; a housing cap forming a feed water inlet port, a purified water outlet port, and a reject water outlet port. Comprising a means for removably interconnecting the cylindrical body and the cap so as to form a substantially hollow interior, comprising a two-stage filter cartridge which can be dropped and mounted inside the housing, the cartridge comprising: A first filter stage having a selected filter media, a second filter stage including a reverse osmosis membrane capable of separating water into a relatively purified purified water and a relatively dirty reject water, and the water inlet. A port is connected to the cartridge to continuously flow water from the water inlet port through the first and second filter stages. Comprising the stage, and means for connecting the cleaning water in the purified water outlet port, and means for connecting said reject water in the reject water outlet, said first
And a second filter stage interconnected to form an integrated cartridge. 2. The reverse osmosis unit for a purification system according to claim 1, wherein said connecting means comprises means supported by said cartridge for sealing engagement with the interior of said cylinder. 3. The first and second filter stages are mounted on a common central support tube, and the connecting means for purified and rejected water separates the purified and rejected water into the central and separate reject water. The reverse osmosis unit for a purification system according to claim 1, further comprising means for passing the cap through a support tube to the cap. 4. The filter medium of claim 1, wherein the filter media of the first filter stage comprises a selected material capable of removing pollutants harmful to the reverse osmosis membrane of the second filter stage. A reverse osmosis unit for the purification system according to the above. 5. A reverse osmosis unit for a purification system according to claim 1, wherein said reverse osmosis membrane of said second filter stage comprises a thin film membrane.