CZ20003349A3 - Filter for removing solid substances from liquids - Google Patents

Abstract

The filter (10) includes a housing (18) having an inlet (42) of purified water. A first filter (12, 16, 58) is provided in the housing (18) for removing solids from water and a second filter (66) steps for performing ultrafiltration or microfiltration and / or reverse osmosis.

Description

Filter for removing solids from liquids

Technical field

The present invention relates to filters for removing solids from liquids. The filter is intended especially, but not exclusively, for the purpose of removing solids from water in the purification of drinking water and for other purposes, for example, as boiler water.

BACKGROUND OF THE INVENTION

There are very few sources of water that can be used for drinking, agricultural or industrial purposes without treatment. The oceans, which are the most abundant source of water, contain a large amount. (30,000 to 40,000 parts per million) dissolved solids. Depending on the particular geographical area, the water also contains sludge and / or sand in suspension. It must therefore be filtered and desalted before being used for any purpose.

Water from rivers, lakes and underground sources is usually contaminated with dissolved solids and solid material that is suspended or dispersed in water. In addition, it may be a biological material whose removal requires microfiltration or ultrafiltration.

It is an object of the present invention to provide a filter which is an improvement on known filters.

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SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is provided a filter comprising a housing having a water inlet for filtration, a first stage filter within the housing to remove solid material from the water entering the housing, and a second stage filter within the housing into which water flows from the first stage filter. membranes for reverse ultrafiltration or microfiltration and / or for removal of solids dissolved in water.

second stage osmosis filter for implementation

In a preferred embodiment, said housing has an elongated shape, wherein said first and second stage filters are adjacent to each other in the length direction of said housing.

According to a further aspect of the present invention there is provided a filter comprising an elongate enclosure delimiting the elongated compartment, the inlet of purified water into the compartment, an outlet from said passed water compartment, an outlet from said brine compartment, a first stage filter in said solids removal compartment. water entering said space, said chamber forming part of said space and said second stage filter, said second stage filter comprising reverse osmosis membranes for ultrafiltration or microfiltration and / or removal of solids dissolved in water, said first stage filter the chamber and the membranes are positioned such that water flows in the length direction of the housing, passing through said first stage filter into said chamber and through the second stage filter to said outlet from the chamber.

-3Overview of figures in drawings

For a better understanding of the present invention and to illustrate the possibility of its implementation, the description of exemplary embodiments refers to the accompanying drawings, in which:

Giant. 1 is a schematic cross-section of a filter according to the invention including a pipe connected to the filter;

Giant. 2 is a front view of the filter disc of FIG. 1 on a larger scale than FIG. 1;

Giant. 3 is a cross-sectional view of the disc according to line III-III in FIG. 2;

Giant. 4 is a rear view of the disc;

Giant. 5 is a view, on a larger scale than FIGS. 2 to 4, of a spiral flow guide;

Giant. 6 is a sectional view, on an enlarged scale, illustrating the way in which a portion of the filter operates;

Giant. 7 is an illustrative view of a reverse osmosis insert;

Giant. 8 is a cross-sectional view of another embodiment of the invention;

Giant. 9 is an end view of the filter of FIG. 8

Giant. 10 is an exploded schematic view of the filter of FIGS. 8 and 9;

Giant. 11 is an illustrative view, on a larger scale, of a portion of the filter of FIGS. 8-10;

Giant. 12 is a cross-sectional view of another embodiment of a filter;

Giant. 13 is an end view of the filter of FIG. 12a

-4Fig. 14 is an exploded schematic view of the filter of FIGS. 12 and 13.

DETAILED DESCRIPTION OF THE INVENTION

The filter 10 shown in FIG. 1 comprises a plurality of porous tubes 12. Each tube 12 has a hairpin bend 14, and the ends of the tubes are attached to a disk 16 which is mounted in a cylindrical housing 18. Between the housing 18 and the disc 16, seals (not shown) are provided, which are fixed in grooves 20 (see in particular Fig. 3) formed on the outer periphery of the disc 16.

Opposite ends of the housing are closed by end caps 22 and 24 which are held in place by the two-piece locking annular members 26. The outer ring 28 of each locking annular member 26 is recessed into the wall of the housing 18 when the housing is made of fiberglass reinforced resin. The inner ring 30 is in the form of a removable split ring whose diameter is reduced before being inserted into the ring 28. The inner rings 30 may be removed by reducing their diameter and pulling out of the housing 18, thereby releasing the end caps.

Between the end caps 22 and 24 and the housing 18 are provided in the grooves 32 and 34 in the end caps 22 and 24 sealing. O-rings (not shown).

End cap 22 and disc 16 define a chamber 36 that includes tubes 12. Tube 38 extends through end cap 22, through chamber 36, and terminates in communication with central aperture 40 of disc 16. Through end cap 22, an aperture 42 opens into the chamber 36. A pump 44 is connected to the opening 42 through a pipe 46, which supplies water for filtration from the source 48 to the chamber 36. The pump 44 is also connected to a reservoir 50 of clean, filtered water. Valves 52, 54

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The pump 44 can pump either filtered or raw water through pump 44.

Holes 56 pass through the disc 16, each end of each tube 12 extending to the respective aperture 56 and the tubes hanging U-shaped below the disc 16 into the chamber 36. The apertures 56 are not arranged axially but at an angle (see FIGS. 2 to 4) so water entering the conical vortex chamber 58 formed on the top side of the disc 16 swirls in the chamber 58. As can be seen from Figures 2 and 4, the apertures 56 are. Arranged in a spiral row.

The helical flow conduit 60 is integral with or attached to the disc 16 and is located within the vortex chamber 58. The conduit lies within the peripheral collar 62 that extends from the main body of the disc 16.

The chamber 58 forms one end closure of the space 64 bounded by the disc 16 and the end closure 24.

Inside the space 64 is a hollow envelope 66 containing two sheets of membrane material through which water can flow.

The two sheets are welded or otherwise joined. along its perimeter. Any type of membrane material can be used. For example, ultrafiltration membranes, microfiltration membranes or reverse osmosis membranes may be used. The sheets are also welded with two tubes 68 and 70.

The tube 68 extends from the envelope 66, through the wall of the housing 18, to the shut-off valve 72. The valve 72 is connected to a pressurized air or water source 74.

The tube 70 passes through the central opening 76 of the end cap 24, extends from the housing 18, and is connected to the valve 78. A plurality of side-by-side bundle-forming envelopes 66 may be provided. Spacer means 80 within envelopes 66 and other spacers (not shown) between envelopes

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99 prevents excessive expansion of the envelopes 66 when overpressure occurs therein.

The water outlet port 82 containing the last remaining solids passes through the end cap 24. From the port 82 the tube 84 extends into the T-piece 86. The other pipes connected to the T-piece are labeled 88 and 90. Tube 88 leads to valve 92 and tube 90 to valve 94.

There is a T-piece 96 between the valve 94 and the pump 44. A valve 98 is connected between the tube 46 and the T-piece 96. From pipe 46, branch pipe 100 leads to valve 102. Tube 38 is connected via pipe 104 to valve 106.

In operation, the water containing the solids to be filtered is withdrawn from the source 48 by the pump 44 and supplied under pressure to the chamber 36 via a T-piece 96 of the valve 98 and the pipe 46. The tubes 12 filter most of the solids out of the water, as described below.

Water that penetrates the walls of the tubes 12 through the pores in the walls enters the interior of the tubes, flows through the internal openings of the tubes 12, enters the openings 56 and then flows into the vortex chamber 58.

The angle at which the holes 56 open into the vortex chamber 58 and the arrangement of the spiral guide 60 promotes the swirling of water in the vortex chamber 58 and a portion of the space 64 immediately above the vortex chamber 58.

The valve 106 is fully open upon actuation and the pressure in the space 64 causes an initial strong outlet of water through the central opening 40 of the tube 38 and the tube 104. This results in a vortex at the center of the chamber 58.

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-7 ··· ·· ·· ·· 44 4 * enters hole 40. Obviously, the water that enters the aperture 40. flows into waste. Thus, the flow through the valve 106 is adjusted after start to achieve a minimum water output sufficient to maintain a constant vortex. By adjusting this flow, it is possible to obtain a flow pattern in which the so-called overflow vortex, which normally exists coaxially with the main vortex, is suppressed. Experimental work has shown that the main vortex extends a certain distance above the disc 16, gradually decreasing in strength until finally becoming invisible. Above the main vortex is an ascending stream of water, but little or no overflow vortex capable of entraining particles.

The final stage of the filtration process is carried out as water passes through the membrane material forming the envelopes 66.

The solid particles remain on the outside of the envelopes 66 and water, substantially devoid of solids, flows through the pipe 70 through the valve 78 and then into the storage container, the water line, or the site of use.

The pressure at the outlet port 76 of the filter 10 is monitored, and when a pressure drop of sufficient size is detected, an automatic cleaning sequence is initiated.

The main part of the cleaning sequence comprises closing the valves 52, 98, 92 and 106 for a short period of time and opening the valves 54, 94 and 102 for a short period of time. As a result, clean water withdrawn from the reservoir 50 is pumped by the pump 44 through the valve 94 to the space 64. The pressure increase in the space 64 results in a proportional increase in the pressure in the tubes 12. Reverse flow through the pores of the tubes 12 cleans the tubes as described below. The cleaning of the tubes 12 is thus carried out by temporarily increasing the internal pressure above their external pressure.

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The material ejected from the outer surface of the tubes 12 exits the chamber 36 through the opening 42, the tube 100 and the valve 102.

The reverse flow of water causes the vortex in chamber 58 to collapse. When valves 52, 98, 92 and 106 reopen and valves 54, 94 and 102 reopen, the valve 106 must be fully opened and the vortex must then be restored.

Since pure water is supplied to the space 64, the flow of water through the envelopes 66 is not interrupted during the cleaning process of the tubes 12.

To clean the envelopes 66, the valve 72 is briefly opened, typically for a second or less, and the envelopes 66 are inflated with air or water under pressure. At the same time, the valve 7 8 closes briefly. The external spacer means between the envelopes 66 prevent them from overflowing and rupturing. The sudden expansion of the envelopes expels the solid material adhering to their exterior, and the total flow from the space 64 to the opening 82 carries the expelled solid material leaving the valve 92.

Obviously, for each envelope 66, a tube 68 and a tube 70 are provided. The tubes 68 and 70 lead to common manifolds.

The tubes 12 are of rubber, rubber compound or synthetic plastic material having a surface to which the solid material does not adhere firmly. The type of surface required can be compared to an automobile tire. While the mud adheres to the tire, the binding is not firm, and if the mud dries, it can easily shake off and if it is wet it can easily be rinsed.

Each tube 12 has a plurality of pores that extend

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9 9 9 99 9 9 9 9 99 from the outer surface of the pipe to the inner surface of the pipe. One such pore, designated 108, is shown in FIG. 6. The pore 108 is wider on the outer surface of the pipe than on the inner surface of the pipe. Preferably, the diameter of the outer pore end is in the range of five microns and the inner pore end is of the order of one or two microns. The wall thickness of the pipe is about 15 mm.

The solid material particles indicated by 110 in Fig. 3 settle in the pores 108 and within a short period of time after the start (from a few seconds to several minutes) there are particles in each pore 108 that act as a filter to allow water to enter the tube interior. 12 but prevent the passage of other solids. It will be appreciated that when water passes through the particulate filter in each pore 108, the solid material entrained therein deposits on the outer surface of the tube 12. This solid accumulation is indicated in FIG. 6 by the reference numeral 112. When inverted occurs. the flow through the pores 108 as described, the solid accumulation is flushed.

It has also been found that the pressure loss in each pore 108 should not be excessive. If the pressure drop is excessive, the particles 110 in the pores 108 and the accumulation 112 of the solids are drawn into the pores 108 with such force that ejection of the material accumulations 112 becomes difficult. Thus, the pores 108 are blocked and the flow through the filter from the tube 46, through the pores 108 in the tubes 12 to the interior of the tubes and thus into the vortex chamber 58 decreases considerably.

The envelopes 66 may be replaced by a spirally wound membrane, for example a reverse osmosis membrane in the form of an insert 114, as shown in Fig. 7. Such a filter will be described in more detail with reference to Figs. 12, 13, 14.

The liner 114 includes a central tube 116 around which

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444 44 44 44 44 44 44 are assembled by assemblies 118 each comprising two sheets 120, 122 of polymer and a spacer 124. The tube 116 has openings 126 arranged in rows extending along the tube. The water in the permeate channels 128 enters the pipe 116 through these openings. The salt retention channels are designated 130.

The two sheets 120 and 122 are welded together to form each assembly 118 about three of their edges. The fourth edges are not welded, but secured by adhesive to the tube 116 on opposite sides of the rows of holes 126 in the tube 116. Thus, each row of holes 126 is in communication with the permeate channel 128 of the respective assembly.

In Fig. 7, for illustrative reasons, the membrane sheets 120 and 122 of the top assembly 128 are shown separately so that the spacer 124 is visible. The other assemblies 118 are shown with welded edges of the sheets 120 and 122 so that the spacer 124 is hidden.

The number of assemblies 118 used depends on the number of rows of apertures 126 since each assembly must be positioned such that its permeate channel 128 is connected to the respective row of apertures.

Once wound onto the tube 116, the membrane sheets 120, 122 of each assembly 118 face-to-face contact with the sheets 120, 122 of the adjacent assembly 118.

After the assemblies 118 are adhered to the tube 116 by the inner edges of their sheets 120 and 122, the assemblies are wrapped tightly around the tube 116 and then secured with tape to prevent them from unwinding. The outer sleeve (not shown) then prevents the sheets 120 and 122 from breaking when water is introduced into the insert 114. The outer sleeve is adapted to be inserted into the housing 18.

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It will be appreciated that the channels 130 are open at both axial ends of the wound insert.

The liner is used in conjunction with the two end caps 132 and 134. The end cap 132 includes a disc 136 and a skirt 138 that extends around the periphery of the disc 136. The cap 132 is at the end of the cartridge from which the brine stream exits. In the disc 136 there is a central aperture 140 that coincides with the pipe 116, and a plurality of apertures 142 through which the brine flows. There is a gap, for example two to four centimeters, between the end of the liner and the disc 136. The function of the end cap 132 is to provide back pressure in the immediate vicinity of the outlet ends of the brine channels. The axes of the apertures 140, 142 are parallel to the axis of the pipe 116.

The end cap 134 is at the inlet end of the liner. It comprises a disc 144 having a central aperture 146 which coincides with the tube 116, and a plurality of apertures 148 between the aperture 146 and the peripheral collar 150 that extends around the periphery of the disc 144. The disc 14 4 may be opposite the end of the insert or up to four centimeters from inserts.

The axes of the apertures 148 are not parallel to the axis of the tube 116, but are at an angle thereto. This results in discrete water jets that pass through the apertures 148 and impinge on the end of the liner 114 at an angle, not along a path parallel to the pipe 116. The aperture orientation is such that the jets swirl in the same direction in which the assemblies are wound.

It will be appreciated that the insert 114 is positioned by an end closure adjacent the disc 16 and an end closure 132 at the other end of the housing 18 adjacent the end closure 24.

Giant. 8 to 11 illustrate a filter 152 that includes a housing 154 in which the diaphragm insert 114 is described with the aid of " _{g & quot;} ; g ^; ^ ..,. ,,. 1. ^ () 1,

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7 and the prefilter 156. The prefilter 156 comprises three cylinders 158 having screens of sieve filter material. The cylinders 158 are in the chamber 160. The inlet to the chamber 160 is designated 162. The water flows through the walls of the screen rolls 158 to the inside of the rolls and from the inside of the rolls 158 to the other chamber 164 through apertures 166. the cylinders 158 are fixed in which apertures 166 are formed, and on the other hand by the end closure 134 of the liner 114.

The brine outlet 170 from the liner 114 and the leaked water outlet 172 are in the end cap 174.

The liner 114 and the disc 168 are held in place by the spacer means 176, 178, and 180. The inlet 162 is at the end cap 182, where the annular members 184 and 186 are also in place to hold the end cap 182 and the end cap 174 in place.

A pipe generally designated 188 connects the interior of the rollers 158 to the outlet 190 in the end cap 182. The waste pipe 192 leads from the chamber 164 through the end cap 182 to the drain.

During normal operation, entrained solids water enters the filter through inlet 162, flows through sieve rollers 158, through chamber 164 from there to the salt retention channels in the insert 114. The permeate exits through outlet 172 and the brine exits through outlet 170.

To clean the filter, pressurized water is supplied to outlet 172, whereby water flows from the permeate channels through the membranes to the salt retention channels. From the salt retention channels, it enters the chamber 164 and from there a portion of the water flows through the pipe 192 to the drain.

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The rest of the water flows through the holes 166 into the rollers 158 and the water entering the rollers 158 flows through the screen and the outer surfaces of the rollers. The remainder of the water flows through line 188 to outlet 190, carrying the solids that have previously passed through the screen of rollers 158.

The pipe shown in FIG. 1 is modified to allow the liner to be cleaned by removing the tube 68 and connecting the valve 72 and the water source 74 directly to the opening 7. The valve 78 is closed when the membrane is cleaned.

Giant. 12, 13 and 14 illustrate a similar filter to that shown in Fig. 1, but having an insert 114 instead of envelopes 66. Further, it has a similar construction to that of Figs. 8-11 but has, instead of screen rolls 158, tubes 12 as described in FIG. 1.

The end cap 134 of FIG. 14 has an aperture arrangement that differs from that shown in FIG. 10. Otherwise, the same reference numerals in FIGS. 12, 13 and 14 as in FIGS. 8-11 are used where possible.

12 to 14 are cleaned in the same manner as described above with respect to FIGS. 8 to 11.

The filters having the vortex chamber 58 are operated in the vertical position as shown in Figures 1 and 12. The filter of Figures 12 to 14 should therefore be operated in the vertical position. 8 to 11 can be operated horizontally.

The tubes 12 can remove all solids of a size above twelve microns. The filter rollers 158, depending on the screen used, remove all solids above about 20 microns. The type of pre-filter selected •• BHSBSSSSSfhV

depends on the solids loading of the input water and the desired final water quality.

It is possible, instead of hoses 12 and cylinders 158, to use a disc filter, preferably a self-cleaning disc filter, or any other type of filter that can remove solids to the extent necessary before the water enters the insert 114 or envelopes 66 for ultrafiltration or microfiltration; to remove dissolved solids.

When small balls of rubber-like material are placed in the chamber 160, they are displaced by the flowing water and tend to jump in the chamber while keeping the solids in suspension and thus help prevent the filter from sticking.

It is also possible to clean the membranes by suddenly closing the valve in the passed water pipe. A shock wave passing in the reverse direction shakes off the free solids in the salt retention channels. A similar effect can be obtained by introducing pressurized air into the passed water pipe.

It is also possible to arrange an electrical winding around the insert 114, as described in PCT application WO 98/30501 (PCT / GB98 / 30501), in order to increase the efficiency of the insert. In FIGS. 8 and 12, the threads are designated 194, 196 and 198. They are embedded in the housing walls during manufacture thereof.

Claims (12)

PATENT CLAIMS A filter comprising a housing having a water inlet for filtration, a first stage filter inside the housing to remove solid material from the water entering the housing, and a second stage filter within the housing into which water flows from the first stage filter, the second stage filter comprising reverse osmosis membranes for ultrafiltration or microfiltration and / or removal of solids dissolved in water. Filter according to claim 1, characterized in that the housing has an elongated shape, wherein said first and second stage filters are adjacent to each other in the length direction of said housing. 3. The filter of claim 1, wherein said housing is vertical, wherein an inlet is provided at the lower end of the housing for supplying water for cleaning to an inlet chamber in the housing, a disc forming part of said first stage filter and representing an upper end of said chamber. a plurality of apertures in said disc, a vortex chamber on top of said disc, the vortex chamber having an inverted cone shape, a plurality of apertures passing through said disc and entering said vortex chamber, the apertures being oriented so that water flowing into said vortex chamber from apertures in said vortex chamber, an outlet from said vortex chamber extending downwardly through said disk from the top of said vortex chamber, and in said chamber a plurality of tubes with porous walls, the interiors of said tubes communicating with said apertures. 855 ^ - 17 • 4 4 4 4 4 4 4 4. The filter of claim 3, wherein said openings are open to said vortex chamber in a spiral row. Filter according to claim 3 or 4, characterized in that in said vortex chamber there is a spiral guide for promoting the spiral flow of water in the vortex chamber. Filter according to claim 3 or 4, characterized in that each end of each tube is connected to a respective one of said openings, the tubes hanging in a U-shape into said inlet chamber. Filter according to claim 1, 2, 3 or 4, characterized in that said first stage filter is formed by a filter comprising a plurality of filter elements which are pressed together and define filter channels therebetween. Filter according to claim 1, 2, 3 or 4, characterized in that said first stage filter comprises a plurality of sieve filter elements through which water flows, wherein the sieve filter elements retain the solid material. 9. The filter of claim 1, wherein said second stage filter comprises a plurality of sealed envelopes of reverse osmosis membranes in a second stage chamber into which water flows from the first stage filter, an outflow of water from the interior of each envelope, means for introducing. fluid under pressure into said envelopes to temporarily pressurize the envelopes, and output from said second stage chamber. HWŠŮé -17for solids that have been separated from the expired water. 10. The filter of claim 1, wherein said second stage filter comprises reverse osmosis membranes wrapped around an expired water tube, wherein the wrapped membranes are in a second stage chamber into which water flows from the first stage filter, wherein for backwashing. the membranes are provided with means for supplying pure water under pressure to said permeate tube. 11. The filter of claim 1 wherein said first stage filter comprises a plurality of compartments having screens of mesh material, said compartments being in a filter inlet chamber, a first outlet from each compartment leading to a second stage filter, a second outlet from each compartment wherein a normally closed valve is provided at said second outlet and means for supplying water through said screen material from the interior of the compartment to said inlet chamber for cleaning said screen material and for supplying water through said compartments to said second outlet while the normally closed valve is open . 12. A filter comprising an elongate enclosure delimiting the elongated space, a purified water inlet therein, an outlet from said passage compartment, an outlet from said brine compartment, a first stage filter in said compartment for removing solids from water entering said inlet into said compartment, a chamber forming part of said compartment, and a second stage filter, wherein the second stage filter comprises membranes for: ··· • · · ······ · · _1O ·········· -18- reverse osmosis to perform ultrafiltration or microfiltration and / or to remove solids dissolved in water, the first stage filter, chamber and membrane being positioned so that water flows in direction of the housing length, passing through said first stage filter into said chamber and through the second stage filter to said outlet from the chamber.