DE2908625A1 - FILTER ELEMENT - Google Patents

Description

PATENT LAWYERS

WUESTHOFF - ν. PECHMANN - BEHR2NS - GOJEl 2

PROFESSIONAL REPRESENTATIVE BEFORE THE EUKOPEAN PATENT OFFICE MANDATA1KES AGREES PRES l'oFPICE EUROPEAN DES BREVETS

-3-

2SQ862S

T> A.-. Basement. J ^ ANZ OTESTHOFF

DR PHIL TEDA ■ yUESTHOFF (1927-1956) DIk L.-1NO. GEEHARD 7O1S (19J2-I971) DIPL.-CHEM.DR. E. BARON YOH PECHMANN DR.-ING. DIETER BEHRENS PIPL.-ING .; DIPL .-- OTRTSCH.-ING. RUPERT GOETZ

D-8000 MÜNCHEN 90 SCHWEIGERSTRASSE 2 TBtEFON: (089) 66ZO JI telegram: protectpatent telex: 584070

1A-51 863

Patent application

limelder: ECODIHE CORPORATION

90 Half Day Road, Lincolnshire, Illinois 60015, U.S.A.

Title

Filter element

909837/0703

Dr ..: fo. ΓΓ.ΑΝΖ wuesthoff PATENTANWÄLTE _DR _ _VHlL . _{PIlEDA VUESTHOPF} <χ ₉ 2 ₇ -ΐ _9ί 6)

WUESTHOFF - ν. PECHMANN - BEHRENS - GOETZ mru-mc. gerhard puls ( _w

DIPL.-CHEM. PR. E. BARON OF PECHMANN PKOSESSIONAt REPRESENTATIVES SEFORE THE EUROPEAN PATENT OFFICE DR.-iNG. DIETER BEHRENS

MANDATAIRES AGREES PRES L'oJFICE EUROPEAN DES BREVETS DIPL.-ING .; DIPL.-TTIRTSCH.-ING. RUPERT GOETZ

D-8000 MUNICH 90 SCHWEIGERSTRASSE 2

phone: (089) 66 20 ji

TELEGRAM: PROTECT PATENT

telex: j 24070

863

Description:

ECODYNE CORPORATION,

90 Half Day Road, Lincolnshire, Illinois 60015, U.S.A.

Filter element

The invention relates to a filter element which is used for filtering or cleaning liquid in a filter system will. In particular, the invention is directed to a filter element that has two different layers of turns having over a central support core.

A filter device is already known which has filter elements made of a perforated cylindrical support core works around which turns of a strand material are attached (US-PS 1,751,000). With these filter elements Undissolved particles are removed from the liquid when the liquid passes through the wrapping material from the outside flows into the support core. The undissolved particles are captured by the wrapping material.

Another filter element with multiple layers of material wrapped around a central support core is known, in which the density of the layers is different (US Pat. No. 3,680,709). The density does not start in the radial direction from the support core because the windings are close to the support core

90S837 / Ö7Q3 / ²

are denser and gradually reduced towards the outside.

It was found that these filter elements have several layers, of which the outermost layers are one have a lower density than the innermost layers, lead to difficulties arising from a tendency to become dirty, result from rewinding limitations and from uneven flow distribution. These disadvantages occur especially when the known wound filter elements are used as a support for a precoat layer can be used which has particles in the grain size range of about 0.26 to 0.037 mm. The precoat particles usually consist of cation and anion exchange resins. These with a precoat layer equipped filter elements are used to purify water by increasing the concentrations of dissolved and undissolved impurities of about 50 parts per Trillion traced back to less than 10 parts per trillion parts.

The known filter elements with a graded winding density j which drops from the central support core are easily closed or clogged by particles, which penetrate to the center of the winding layer when liquid passes through the filter element in the direction of passage flows during the cleaning phase. Because of the narrow spacing of the turns near the support core, it is difficult to sufficient flow rates of the liquid through the filter element in the direction of passage during the To achieve the backwash phase in order to loosen and to loosen the particles that have flown in within the windings of the filter element remove.

According to the invention is a filter element with two or more Winding layers are provided, which avoids the disadvantages of the known filter elements in that the flow distribution improved and thereby the backwashing of the filter element is facilitated, the tendency to

909837/0701 / 3

Soiling is reduced during the operating phase. . With one filter element, these advantages become one perforated tubular support core with an inner layer of filter material arranged around the core and a Looks outside. The filter material arranged around the inner layer is achieved in that the outer layer has the ability to have smaller particles than the inner layer capture. This ability is referred to as "particle retention" in terms of particle size.

In a preferred embodiment of the invention includes the filter element has several layers of a strand material or fiber material and is provided with a To be provided with precoat layer of particles in the grain size range from 0.26 to 0.037 mm. The filter elements are usually placed in a filter container through which the liquid to be cleaned flows as it does on is well known in the fluid purification art.

The liquids are cleaned by first producing particles in the grain size range from 0.26 to 0.037 mm the outside of a filter element according to the invention be stranded in a wrap. The liquid to be filtered is provided with a precoat layer Filter elements passed. The filter device is backwashed periodically to remove all debris and those trapped in them To remove impurities, the filter elements are replaced with a layer of fresh particles be coated.

The inventive arrangement of the windings on the support core, where the layer with the greatest particle retention number is closest to the support core and the layer with the smallest particle retention number is furthest from the support core limits the area for filtering or cleaning of the liquid flowing through the filter elements essentially on the layer on the outer circumference

lh

900937/0703

of the filter element, "This restriction of the filter surface to a relatively thin annular volume is desirable in particularly, wen the filter element is used within a filter apparatus in which the filter elements with a precoat layer of finely-divided resin particles in the particle size range of O ₁ 26 to Oj037 mm grain size be coated. In the case of these inventive filter elements provided with a precoat coating , the area that tends to become soiled is much smaller, and undissolved particles do not settle inside the element under the outer circumferential surface in such a way that they are difficult to remove by rewinding.

When synthetic resins or other particles through the outer layer are printed, which in the event of a possibly intermittent increase in flow of the filter element passing through Liquid can be the case, these particles are distributed over the layers of the wrapped element » In this way, some particles are removed from the filter element as a result of the tortuous flow path through the filter element Windings captured, but the open flow area or the free flow cross section is not up to is reduced to a value at which the ability of the filter element to pass liquid is substantially reduced is"

In the case of the filter elements according to the invention, the Backwashing process improved because the outside view forms a larger pressure barrier for the backwashing liquid flows in from the support core than is the case with the inner layer made of the strand material. Because of this, the backwashing liquid tends to distribute itself evenly over the length of the filter element when it is applied to the The increased pressure barrier formed by the outer layer meets.

An embodiment of the invention is explained in more detail with reference to a schematic drawing, wherein further advantages and embodiments of the invention result. It shows: S0S837 / 07QI

FIg. 1 is a partially sectioned side view of a filter system with a container in which replaceable cylindrical filter elements are arranged according to the invention;

2 shows a perspective illustration of a filter element, with the winding layers from Strand material and parts of the central support core are cut away; and

3 shows a longitudinal cross section through the filter element Line 2-2 in Fig. 2.

The filter device 10 shown in FIG. 1 corresponds to that shown in detail in the applicant's US Pat. No. 3,279,608 and described design. The filter device 10 receives a feed stream, filters it and releases it The filtrate.

The filter container 10 consists of a generally cylindrical vessel made of steel or the like. With an outwardly convex protruding cover 11 and an outwardly convex protruding bottom 13- The container is in an inlet chamber 15 and divided into a filtrate chamber 16 by a downwardly bulging tube bottom plate 17, which with the inner wall of the container 10 is connected by welding or the like. The feed line 12 extends through the bottom 13 of the container 10 and is in communication with the inlet chamber 15, so that all of the inlet water flows directly to the inlet chamber 15. The inlet pipe 12 Is connected to the tube sheet plate 17 by welding or the like. In this way there is no direct one Connection between the feed chamber 15 and the filtrate chamber 16.

A multiplicity of filter candles is located within the inlet chamber 15 or filter elements 18 are arranged through which the feed must flow before it reaches the filtrate chamber 16 and exits the container 10 through the outlet line 14. The filter elements 18 are annular

909037/0703 / 6

-κ-

and provided with a wrap, the two or more layers having a regulated ability according to the invention for retaining particles. Each filter element 18 is located within the inlet chamber 15 of the filter canister 10 held by a bracket 20 in the installation position. This holder 20 holds the filter elements 18 releasably on one of several filter seats 30 which are connected to the tube sheet plate 17. The filter elements 18 are installed and removed through a small access opening 22 on the filter container 10. The manhole 22 is provided with a lid 24 which, if desired, can be removed or opened to the interior of the container 10 accessible.

The filter container 10 is also provided with a ventilation connection 26 and with a reserve connection 28, the is locked in the present case. Different configurations come into play for the ventilation connection 26 Consideration, the selection generally depending on the use of the filter container 10 and familiar to the person skilled in the art is. Jed

Each filter seat 30 consists of a short steel tube of the like. Which extends through an opening in the tube base plate 17 extends therethrough and is welded or otherwise connected to the tube sheet plate 17. The filter seats extend substantially parallel to the longitudinal axis of the filter container 10 and create a connection between the Inlet chamber 15 and the filtrate chamber 16. The filter seats 30 support the filter elements 18 on the seats are secured in their position by the bracket 20. In a typical embodiment, the filter elements have a Length 127 and 203 cm, have an outer diameter between 2.5 and 7.5 cm and can be used as a one-piece component executed or from several sleeves of the usual. approximately

25 cm long to be assembled into one component.

/ 7 909837/0703

A filter element 18 according to the invention is shown with its details in FIGS. This filter element 18 has a tubular support core 82 and two layers 84 and 86 of wound strand material. The support core 82 is preferably made of corrosion-free steel and is provided with a multiplicity of symmetrically spaced openings, whereby about 20 % of the area is open on the outer circumferential surface, as a result of which on the outer circumferential surface of the support core 82. The preferred percentage of the area or perforations of the support core 82 is from 5 to 65 percent, and the inside of the support core 82 is preferably between 1.9 and 3 »5 cm in diameter.

The inner layer 84 and the appearance layer 86 are made in a known manner by having a continuous Rope made from a thread or from other bar material such as nylon, orion, polypropylene, cotton and the like. In a helical shape Way was wound on the support core 82. The cross-section of the thread or other strand material can be round, oval, triangular or the like, as long as only the inventive ability to hold back Particle is obtained. The cross-section of the thread can change when it is wrapped, which is due to the proximity between adjacent ones Strands and depends on the winding tension.

The distance between adjacent strands is 1.6 mm or less, with less than Λ '% open area, which gives protruding fibers or other irregularities on the surface of the thread the possibility of trapping particles and thereby the overall ability to hold back particles carried by the Particle contact with the comparatively strong twist of each thread strand is obtained to increase. The particle retention ability. of each thread layer depends on other factors besides the thread spacing. The particle retention capacity can be changed, for example, by changing the winding tension, the thickness of each thread layer or the pattern

/8th

909037/0703

: 9Q.

are., which are formed during the gate and rewinding of the strand will. Particle retention can also be change with the thread type, the thread material and with the treatment method of the thread. For example, a lylonfaden be roughened so that it no longer has a smooth surface, which has the ability to hold back particles of the influenced last tubular filter winding.

The manner in which proper particle retention is established is not critical to practicing the invention, and most of the aforementioned manufacturing techniques are well known to those skilled in the art. What is essential, however, is that the filter element 18 is wrapped in such a way that the different ability to retain particles is achieved, as described above with the term "split retention number ^11. This particle retention number of a filter element layer is the longest dimension of the smallest particle whose distance is through the filter elements layer 90% or more, are supplied in an aqueous suspension at about 21 ⁰ C when particles m of predetermined size composition with a flow rate of about 142.6 l / min. for example, a filter element layer has a particle Retention index of 25 µm when an amount of the test dust (Fine Arizona Air Dust) is passed through the filter element in an aqueous solution as described above and 90 % or more of the particles with a maximum dimension of 25 Ui or more are retained by the filter layer The influence of the test dust is not critical, e Tests were carried out with a concentration of 1Οθί 25 mg / l.

The aforementioned test dust, which is used for the measurements made in connection with the invention, is in Commercially available. It is composed of particles of different sizes in the following way:

/ um area ^ portion

0-5 39 ± 2

5-10 18 ί 3

10-20 16 ± 3

20-40 18 + 3

40-80 9 ± 3

In the context of the invention, not only the commercially available test material, but also other material with the the same particle composition can be used.

In the preferred embodiment of the invention, two layers of strand material are provided, an appearance layer 86 and an inner layer 84. As used herein, the term "layer" refers to turns of strand material, which are sufficient to achieve the desired particle retention number evenly along the filter element. Accordingly, a "layer" can have many overlapping ones Contains strands of material, depending on the intended winding pattern. Conversely, one layer can be another Layer covered, have no visible separation from the covered layer, which has the same particle retention index having.

The number of turns along the support core and the increase in the pitch of the adjacent strand within the overall winding are determined by the particle retention desired. The particle retention number of the Outer layer 86 is less than the particle retention number the inner layer 84. To the extent that intermediate layers are provided between the inner layer 84 and the outer layer 86 Preferably, each intermediate layer is given a particle retention number which is smaller than that of the adjacent inner layer. This way becomes a Filter element 18 is provided with multiple layers whose particle retention number is from the inner layer 84 to the

Outer layer 86 falls off.

As part of water purification by reducing pollution from about 50 parts per trillion to about 10 parts per trillion using a precoat A mixture of cations and anions exchange resins in the grain size range from 0.26 to 0.037 mm is preferred The outer layer 86 with a particle retention rating between 1 and 25 µm and an inner layer 84 with a particle retention number between 25 and 100 µm. In this preferred embodiment is the filter element 18 is a surface filter, that is to say a filter with a minimum working depth of the filter surface, this being Depth of the thickness of the outer layer 86 corresponds.

In the embodiment according to the invention, the inner layer leads 84 made of wrapped material for improved distribution of the backwash flow, which contributes to the pressure drop is to be returned along the flow path of the backwashing liquid before reaching the outer layer 86. Further the presence of the inner layer 84 leads to an enlargement of the filter surface formed by the outer layer 86 » and this enlargement is achieved with less effort than in the case of an enlargement of the diameter of the core 82, which would mean an increase in the amount of material of the core 82. This enlargement of the Filter surface leads to a considerable increase in the operating time until the filter element is exhausted Compared to a filter element in which the main filter area is close to a support core of comparatively small size Diameter is arranged. The use of a filter element 18 with an outer layer 84 that has a smaller Having particle retention number as the inner layer 86 also offers the advantage of an inner winding volume, which pours out particles that are printed through the outer layer 86, which is particularly indicative of the occurrence can be attributed to flow surges or a pressure increase in the feed liquid. This penetrated

909837/070 $ Z ₁₁

Particles are therefore normally in the interior volume captured without noticeably obstructing the flow of liquid through the filter during the operating phase.

When operating the system shown in Fig. 1 is a Aqueous pulp from a precoat, in the present case finely divided ion exchange resin in the grain size range from about 0.26 to 0.037 mm stored in a precoat container 32. A line 34 with a shut-off valve 36 connects the precoat tank 32 to a pump 38. A transport line 40 connects the pump to the inlet line 12 of the filter canister 10. One in the transport line Valve 42, which is arranged near the pump 38, controls the passage of the fluid supplied by the pump 38 liquid precoat mash.

The water to be cleaned and softened is supplied via a feed line 44 with an inlet valve 46. the Feed line 44 is to the transport line 40 between the valve 42 and the inlet line 12 connected.

The outlet line 14 of the filter container 10 is in a T-shaped connection piece 52 with a pure water line 48 and a precoat return line 50 connected. The pure water line 48 is to consumers, not shown, such as For example, a steam generator and the like. Connected and provided with a valve 54. The alluvial return line 50 is connected to the precoat tank 32 and has a valve 56 for controlling the flow of liquid back to the Alluvial tank 32.

A bridge line 58 with a valve 60 connects the precoat return line 50 and that from the precoat tank 32 outgoing line 34. A drain line 62 with a valve 64 is also connected to the inlet line 12.

/ 12 909837/0703

During the precoat phase, a precoat layer of finely divided ion exchange resin particles in the size range is formed from 0.26 to 0.037 mm on the inlet side © of the filter elements 18 deposited, that is to say on the side from which the water to be treated is fed to the filter elements 18. In a corresponding manner, a filter cake forms within and on the inlet side of the precoat during the filter phase .

In order to prepare for the operational phase, an initial process is required applied to the filter elements 18. For this purpose, the pilter container 10 is filled with slightly contaminated water, for example demineralized water. A Slurry from the precoat and demineralized water is produced in the precoat tank 32, the precoat are ion exchange resin particles in the grain size range of about 0.26 to 0.037 mm.

During the precoat phase, all valves with the exception of valves 36, 42, 56 and 60 are closed. The precoat process is initiated by switching on the pump 38, the the precoat slurry from container 32 through conduit 34 sucks. This slurry is pumped 38 through transport line 40 and inlet line 12 into the filter container 10 funded. The pressure of the incoming precoat slurry pushes the demineralized water in the filter container 10 through the filters 18 and out of the filter container 10 out via the filtrate chamber 16 and the outlet line 14. Part of the demineralized water flows through the Return line 50 to precoat tank 32, and another part flows via bridge line 58 to line 34.

In the further course of this precoating phase, the precoating agent occurs with the inlet-side surface of the filter elements 18 in contact. The finely-divided synthetic resin particles of the precoat are separated from the aqueous slurry and are deposited as a precoat on the Outer circumferential surface of the filter elements 18 from. The alluvial

Medium pulp is circulated in this way through the filter system until a precoat layer of sufficient strength is deposited on the outer circumference of the filter elements 18. The precoat phase is ended in that the valves 36 and 56 to be closed. Now the filter system is ready for treatment of feed water ready. The thickness of the precoat layer is not critical; the precoat layer preferably has however, a thickness in the range from about 1.6 to 50 mm, in particular about 3 »2 to 25 mm and even more specifically 3.2 to 16 mm.

The operating phase, that is to say the cleaning of water, is initiated in that the valves 54 and 46 are opened. In this case, untreated water flows into the filter system via the supply line 44 and passes through the transport line 40 to the inlet line 12 and into the filter container 10. The pressure of the incoming untreated water causes that the water flows through the precoat, the filters 18 and the filtrate chamber 16 to the outlet line 14. To When this operating flow is formed, the valves 42 and 60 are closed and the pump 38 is stopped.

When the untreated water flows through the precoat, an ion exchange reaction takes place in which dissolved impurities are removed from the water. In addition, undissolved impurities are removed from the treated Removes water when it flows through the filter elements 18 provided with a precoat layer. With As the operating phase progresses, a filter cake of undissolved impurities forms on and in the precoat layer on. The purified or treated water flows through the filtrate chamber 16 and the outlet line 14 to Delivery line 48. The purified water is supplied to a storage container or another via the delivery line 48 Facility fed.

/ 14

909837/0703

If necessary, the synthetic resins are exhausted and have to be regenerated and removed. "Then the operating phase" ends by closing the valves 46 and 54 ", the filter container 10 is then cleaned are Reinigmigsgas, usually air are introduced into the interior egg-filter elements 18 at their lower ends j so that the filter elements 18 fortsehreitedn of Ih = rem Zn its lower end cleaned "the air is by opening a Ventils.66 in an air line 68 supplied ^ This is in connection with the outlet line 14 “At the same time, barrels are introduced into the filter elements 18 by opening a valve 74 in a backwash line 76, which communicates with the outlet line 14. The pressurized air and the backwashing water then flow - Into the piltrate chamber 16 and from there upwards into the interior of the filter elements 18 »Preferably, d The air flow rate is about 0.3 to 0.6 mm / min and m filter = surface j while the water flow rate is about 20 l / min and m filter flat «, the drain valve 62 is controlled ρ so that the water level in the container 10 sinks slowly, preferably at a speed of about 25 to 38 cm / min. Therefore, the air and the water flowing into the pilter container 10 endeavor to flow first through the upper section of the filter elements 18 and thereby remove the precoat there.

After the filter container 10 has drained, the drain valve 64 is closed and the container 10 is again filled with liquid which flows through the filter elements 18 in the opposite direction. After the container 10 is filled to a height of about 15 cm above the upper ends of the filter elements 18, the valves 66 and 74 in the air line 68 and the backwash line 76 are closed and the backwash water is opened by opening of the valve 64 drained.

/ 15 909837/0703

The drain valve 64 is closed and the filter elements 18 are again opened by opening the valves 66 and 74 in FIG the air line 68 "or the backwash line 76 backwashed.

With a slightly higher flow rate of, for example 40 to 80 l / min and m filter area worked.

Air is also supplied with a throughput of about 0.45 only / min

and m filter area supplied. After the container 10 to a level above the upper ends of the filter elements 18 is filled, the drain valve 64 is opened again, so that the liquid level at a rate of about 25 to 38 cm / min can drop while the supply of Air and backflow liquid is continued. The backwash valve 74 is closed and the drain is allowed to run continued for a short time with simultaneous supply of air only in order to ensure complete emptying. After the container 10 has been emptied, the drain valve 64 and the air valve 66 are closed. The backwash valve 74 is opened so that the container 10 fills for the third time. Watch the filling of the container 10 the ventilation 26 and the valve 74 in the backwash line 76 are closed. The container 10 is filled with water, and now a new precoat can be applied to the filter elements 18 in the manner described above.

Although air is used as the cleaning gas as described above, other gases such as nitrogen, oxygen and the like can also be used. However, the use of air is generally the most economical and air is readily available in most plants. In a corresponding manner, liquids other than water can also be used during the backwash phase. Examples of such liquids are alcohols, carbon tetrachloride, detergents and soap solutions. The liquids preferably have a temperature in the range between 38 and 93 ^° C

909837/0701

Typical solid ion exchange resin particles, which can be used in the context of the special filtering described above, are of the divenylbenzene-styrene copolymer type, of the acrylic type, of the sulfonated carbon type and of the phenol type Ammonium oxide can be used. Typical solid anion exchange resin particles which can be used are phenol-formaldehyde type _9, divinylbenzene-styrene copolymer type, acrylic type, and epoxy type. The anion exchange resin particles can be used, for example, in the hydroxide or chloride form. Suitable synthetic resins are commercially available in large-grain form. The finely divided synthetic resins used are produced by comminuting the synthetic resins to the desired grain size range. These synthetic resin particles are regenerated and washed before they are used.

The filter elements according to the invention were used in connection with the use of a swivel layer described from finely divided ion exchange resin particles, however, the filter elements according to the invention are the same Can be used if the precoat layer made of treated or untreated kieselguhr, cellulose fibers, polyacrylonitrile fibers or consists of another carrion wash material 5 what is understandable for the expert without further information » While the embodiments described above are preferred, many modifications and refinements can be made which do not lead out of the scope of the invention.

909837/0703

Claims (5)

DR.-INO. PPANZ ^ UESTHOPF PATENTANWÄLTE m_ pK1L- f REDA WUESTHoff (1927-1956) WUESTHOFF- ?. PECHMAN N-BEHRENS-GOETZ dipl-ino. g «hard pulse DIPL.-CHEM. DR. E. BARBER OF PECHMANN PROFESSIONAL REPRESENTATIVES BEFORE THE EUROPEAN PATENT OFFICE DR.-ING. DIETER BEHRENS MANDATAIEES AGKEES PRES l'OPE'ICE EUROPEEN IiES BREVETS DIPL.-ING .; DIPL.-WIRTSCH.-ING. RUPERT GOET2 D-8000 MÜNCHEN 90 SCHWEIGERSTRASSE 2 telepon: (0S5) 66 20 ji TELEGRAM: PKOTECTPATENT TELEX: J 24070 1A-51 863 - Patent claims 1.) Filter element5 in particular for use with a TÖaschv / emmschicht from particles in the grain size range of 0.26 "to 0.037 mm and for periodic backwashing and renewal the swelling layer, consisting of a perforated, tubular core and at least two layers of filter material disposed around the core, thereby characterized in that the outer layer (86) has a lower particle retention rating than the inner layer (84). 2. Filter element according to claim 1, characterized in that g e k e η η => ζ e i c Ii η e t that the particle-retention number the outer layer (86) is between 1 and 25 / tun. 3 «A filter element according to claim 1 or 2 _S characterized in that the particle retaining nominal number of the inner layer (84) between 25 and / um is 100 ,, 4. Filter element according to one of claims 1 to 3, characterized in that the inner layer (84) of strand material wound around the core (82) and the outer layer (86) of strand material wound around the inner layer (84) Strand material consists. / 2 909897/0703 5. Filter element according to one of claims 1 to 4 with intermediate layers arranged between the inner layer and the outer layer, characterized in that that the interlayers have a lower particle retention index than the adjacent inner layer, with the particle retention index progressively drops from the inner layer (84) to the outer layer (86). 909837/0703