DE102006048080A1 - Device for filter-aid-free filtration of medium, comprises a coiled steel wire, which is used as filter and is a flexible-plastic wire with a form-stable, self-supporting cylindrical structure linked up in longitudinal direction - Google Patents

Abstract

The device for filter-aid-free filtration of medium, comprises a coiled steel wire, which is used as filter and is a flexible-plastic wire with a form-stable, self-supporting cylindrical structure linked up in longitudinal direction, and a collection chamber (60) for filtration of dirt particle. The coiled steel wire is combined with a filter bundle (26). A gap width is evenly variable over the entire length of the coiled steel wire. The coiled steel wire consists of a metal with elastic characteristics. The coiled steel wire has a coil ratio (w) of 5.5:7.5. The device for filter-aid-free filtration of medium, comprises a coiled steel wire, which is used as filter and is a flexible-plastic wire with a form-stable, self-supporting cylindrical structure linked up in longitudinal direction, and a collection chamber (60) for filtration of dirt particle. The coiled steel wire is combined with a filter bundle (26). A gap width is evenly variable over the entire length of the coiled steel wire. The coiled steel wire consists of a metal with elastic characteristics. The coiled steel wire has a coil ratio (w) of 5.5:7.5, where w is defined as the quotient from the average diameter (D) and the maximum radial profile dimension (D). The steel wire has a larger cross section in spiral longitudinal direction than in radial direction. The steel wire has symmetrical conical cross section, a semicircular cross section and a two-edge profile. The gap has a positive conicity in perfusion direction. The initial gap is variable in the range of 0-3 mm. The filter bundle has medium-close connection (28), is enclosed by housing and is inserted into an oil tank (40). The collection chamber is arranged inside and outside of the filter device. A discharge screw is intended for draining the collection chamber. An independent claim is included for a method for filter-aid-free filtration of medium.

Description

Field of the invention

The The present invention relates generally to a filter device for filter aid-free filtration. In particular, the Invention a gap filter for solid / liquid separation and / or gas filtration. All Specifically, the present invention relates to a split filter with variable Gap width. The invention also relates to a method for filter aid-free Filtration.

Background of the Invention, Prior Art

The Filtration in particular of process liquids belongs to the central basic operations of process engineering. Due to specific Characteristics of the media to be filtered and the process conditions Every separation process has its own characteristics. Through the development ever finer particles, for example in paints, suspensions and others Products, and the increasing demands on the separation limits and the grain spectrum, new approaches are needed become. In addition, there is an ever increasing attempt to reduce the proportion of solids increase in the product, which is why rising viscosities have to be overcome.

Already A long time ago filter devices became filter aid-free Filtration of media to be filtered, so-called gap sieves or Split filter, with changeable Slit width developed compared to the previously known Slot sieves offered the advantage that not many single sieving devices had to be kept ready with different gap widths over the the separating material is guided one after the other has been.

So is, for example, from the DE 23 25 418 B2 a gap screen with variable gap width known, which consists of screen bars and inserted between the screen bars, the gaps between the screen bars partially filling, mounted in a frame elements, the screen bars and / or the elements are profiled bars with, for example, wedge-shaped cross-section, the profile of a Changing the gap widths by varying the position of the elements between the sieve bars allowed.

meanwhile are used in the dead-end filtration self-cleaning split filter as Alternative to bag and bag filters used. Let it be with canned filters e.g. aqueous or separate aggressive media. These devices consist of a canned filter insert, in which a wire coil-shaped Longitudinal bars wound and welded at each crossing point. As the steel wire exactly on the longitudinal bars is fixed, resulting in uniform columns with a gap width from 30 to 2000 microns. When flowing through of the filter insert, the dirt particles are deposited on the gaps from. If the filter cartridge is used manually or by an electric drive rotated, the dirt is stripped by a fixed device and sinks into a mud-collecting room where he opens by opening a Ball valve is discharged.

The EP 0 810 010 B1 describes a filter device for filtering aid-free filtration of media to be filtered, wherein as filter a wire-like filter wire is used, which is wound around an at least substantially cylindrical first support body to a filter coil, of the liquid to be cleaned in the axial and axial column of the wound filter coil can be flowed through in the radial direction, wherein the filter wire for cleaning the adhering to it solid particles from the first support body of the first filter coil on a second support body of a second filter coil is wound.

adversely on the known from the prior art gap screens or filters is on the one hand that they are designed in several parts, which manufacturing technology very expensive is. For another such solutions a relatively large one Construction volume in relation to the filter surface.

One Another disadvantage with flat or arcuate split filters, for the also solutions with changeable Gap width are known, is that large diameter or a small or missing curvature the wire grates support rods across behind the filter wires make necessary, with which the filter wires are welded and so the desired gap width guarantee, but on the other hand also prevent the wanted change.

Also is disadvantageous that for the cleaning of the cylindrical gap filter separate devices needed which are the deposited on the gap front side material by means of scraping tools continuously or at certain intervals.

Summary of the invention

It is therefore the object of the present invention, a gap filter to provide the said disadvantages of the prior art avoids.

These and further objects are achieved by the split filter according to claim 1 and the method according to claim 22 solved. Further advantageous embodiments are set forth in the subclaims.

Brief description of the drawings

The Invention will be explained in more detail below with reference to the drawings. In this demonstrate

1A to 1F schematically the preferred profile wire cross-sections used in the invention;

2A to 2D schematically shows the structure of a profile wire coil of the device according to the invention in the closed and open position;

3A to 3C a filter bundle constructed from profiled wire spirals according to the invention and arranged in a housing for filtration from outside to inside with manually operated gap width change; and

4A to 4C a filter bundle constructed from profiled wire spirals according to the invention and arranged in a liquid container for filtration from the inside to the outside with an automatic gap width change initiated by the internal pressure.

Detailed description of an embodiment

According to the invention is a Self-cleaning and self-supporting gap filter with changeable, i. variable gap width from a suitable in, described in detail below Way coiled wire provided. The term "self-supporting" means in this Context that the gap filter according to the invention has no support body, around which the wire has to be wound.

In the production of helix made of elastic-plastic material (eg steel or other known metals or metallic alloys with elastic properties, such as brass, nickel or titanium) with the sharpest possible filtering edges, ie, without or with only a very small Edge rounding <0.1 mm, with a constant cross-section with a small outer diameter smaller than about 20 times the maximum wire size (similar to a tension spring or a Bowden cable), creates a dimensionally stable, longitudinally biased cylindrical structure, which in longitudinal stretching with a bias Exceeding disproportionate tensile force within the elastic range of material stress results in a uniform opening gap between the helical layers over the entire length. The dimensional stability is primarily dependent on the quotient of mean winding diameter D and maximum radial profile dimension (profile thickness) d known in coil springs as the winding ratio w. In the case of technical tension springs this is usually in the range w = 3 to 20. For the tension prestressing, besides the winding ratio w = D / d, the winding pitch, ie the profile dimension in helical longitudinal direction (corresponds approximately to the profile width b), is added, with conventional tension springs being off Round wire b = d. The wire cross section is preferably 0.2 to 4 mm ² . At a preferred ratio b / d = 2/1 this corresponds to a profile thickness d (in the radial direction of the helix) of approximately 0.25 to 1.5 mm and a profile width b (in the longitudinal direction of the helix) of approximately 0.5 to 3 mm. Outer or inner diameter are thus at a reduced compared to normal tension coil winding ratio of w = 3 to 10 about D _a = 1.0 to 15 mm or D _i = 0.5 to 12 mm. The spiral length can be arbitrarily long in the production, but is not for use as a gap filter to ensure a sufficiently constant gap width over the helical length in a horizontal mounting position preferably not more than about 100 turns of wire (ie <50 to 300 mm) and vertical mounting position not more than approx. 500 turns of wire (ie <250 to 1,500 mm).

The Spring stiffness is u.a. inversely proportional to the 3rd power of the Winding ratio, i.e. at an enlargement of the winding ratio on the 10-fold, as it is known in wound cylindrical Partition filter baskets is usual, the longitudinal stiffness decreases to 1/1000 off, so without supportive carrying bars no uniform gap width to guarantee. But the weight of the profile wires would be without support bars already to intolerable deformations both in the helical longitudinal direction as also the radial position of two adjacent turns lead.

Of the used according to the invention Profile wire is preferably in its longitudinal direction in its cross section greater than in the radial direction, whereby at the same material deformation and same winding ratio smaller outer diameter and a stronger one longitudinal prestressing possible are as with the conventional ones Gap filter profiles with opposite cross-sectional relationships, because with these the larger profile height for the flexural rigidity the wire profiles between the support profiles is required.

In general, according to the invention profile wires 2 with non-circular, ie, oval or polygonal, preferably simply symmetrical, conical cross section with at least two opposite, as sharp, ie, not or only minimally rounded edges 4 used, which form only a single filter gap in the form of a helix within the helical surface. Depending on the intended filtration direction from outside to inside or from the inside to the outside, the gap opening angle on the inlet side is very large, ie close to or equal to 180 °, and relative to the outlet side small, but> 0 ° (cf. 1A to 1F and 2A to 2D ).

The preferred profile wire cross-section is a two-edge profile ("not quite half-round profile") according to 1A , It is a one-sided oval wire 6 , Wherein the not completely semicircular cross-section (the profile thickness d is only slightly smaller than half the profile width b) of itself gives the desired for the Filtrierspalt positive taper a in the flow direction. Further preferred embodiments are a concave oval wire on both sides 8th ( 1B ), as well as a convex-concave oval wire 10 ( 1C ). Their advantage over the former two-edge profile consists in a cheaper production. Three further preferred embodiments according to the 1D to 1F have used as semi-finished flat wire profiles 12 , preferably with cut edge and the desired thickness-width ratio, which are provided by appropriate rolling with the required taper a, either without cross-compression ( 1D ) or with cross-compression ( 1E ) or by transverse bending ( 1F ).

These Meet profiles not only the aforementioned, mentioned as positive for the inventive solution geometric Relations, but are in the production by pulling and / or Rolling less tool-consuming and in the further processing in spring-winding machines also simple and to lead safely.

By winding the profile wire 2 with a small helix diameter and longitudinal prestressing of the adjacent wire windings similar to a tension spring strand is thus a radially inward ( 2A and 2 B ) or outside ( 2C and 2D ) rising, conical gap, each starting at gap width 0, obtained. 2A shows schematically the structure of a profile wire helix 14 an embodiment of the filter device according to the invention for a filtration from outside to inside with still closed gap with the geometric profile and helical parameters profile width b, profile thickness d, coil diameter D, inner diameter D _i and outer diameter Da. 2 B schematically shows the same profile wire coil 14 , but in the operating position with the filter gap open, specifying the gap width s and the conicity a, which increases further inwards, as well as the inflow of the medium to be filtered (arrows 16 ) and the effluent of the filtrate (arrow 18 ). 2C shows schematically the structure of a profile wire helix 20 an embodiment of the filter device according to the invention for a filtration from the inside out with the gap still closed. 2D schematically shows the same profile wire coil 20 as 2C , but in operating position with opened filter gap, indicating the inflow of the medium to be filtered (arrow 22 ) and the effluent of the filtrate (arrows 24 ).

By longitudinal stretching of the individual coils 14 . 20 (see. 2 B and 2D ) or bundles arranged spirals 26 (See eg the 3A and 3B , in which 3A a section along the line AA the 3A represents) with one or both sides non-positively and media-tight connections arranged 28 a uniform, distance-proportional, very sensitive gap opening takes place over the spiral length. For example, a profile width b of 1 mm, a helix length of 100 mm and an extension of 1 mm results in an average gap width s of only 10 μm.

Depending on the gap direction, ie, gap orientation, filtration now takes place from the outside to the inside ( 2 B . 3A and 3C ) or from the inside out ( 2D . 4A and 4C ). In the 3A and 4A is the inlet of the medium to be filtered with 30 and in 3A the course of the filtrate with 32 characterized. In the filtration from the inside to the outside (see. 4A and 4C ) there is also the procedurally favorable way to effect the gap opening by the back pressure of the medium to be filtered, the gap width is staudruck- and thus volume flow dependent. At the end of the volume flow, the gap closes again by itself and thereby also causes an automatic cleaning of the retained solid particles (eg dirt particles in a hydraulic fluid). In addition, such a "return filter" acts 38 in case of installation, for example in an oil tank 40 at the same time as a flow diffuser to calm the return flow into the tank 40 (see. 4A ).

The simple cleaning of the filter according to the invention is not only by closing the gap when relaxing the coil (this method works especially with grainy ones and similar Solids that accumulate on the gap front). In sticky or fibrous components of the filter cake, as usual, also cleaned by backwashing, However, here preferably with simultaneous further increase in the Gap width z. B. on a multiple of the set during filtration Value.

The filter according to the invention allows a smaller space with the same filter area. So z. B. for the two in the 3A to 3C and 4A to 4C shown bundle variants only about 1/4 of the volume per m ² filter surface of a conventional cylindrical gap filter with the same diameter as the bundle outer diameter selected here. The preferably on both sides non-positively and media-tight connections arranged 28 for the filter packs preferably consist of three congruent perforated plates 44 . 46 , where the outside 44 are rigid and the intervening 46 elastic (eg. Of rubber or similar material). The perforated plates can be made from a one-piece ( 3A to 3C ), eg deep-drawn and flanged during assembly, or a multi-part ( 4A to 4C ) Connection flange 48 . 34 enclosed and pressed against each other so that all helical ends are held at their outer diameter of the rubber and sealed ( 3C and 4C ). For larger bundles, the three perforated plates can additionally by individual fasteners 50 ( 4B making a cut along the BB line of the 4A represents), eg screws or rivets or the like, be braced.

The not quite semicircular profile of the wire has the advantage that the Gap already has a positive conicity at its "beginning", which is steadily increasing. Furthermore can be with this profile smaller and more uniform winding diameter as with V or trapezoidal Profiles that are higher as are wide, achieve.

The gap adjustment by changing the length of the coils can, as in 3A shown, very simply by means of example. An adjusting spindle 52 and a knob 54 take place, as it is known from Ventilstelleinrichtungen. In the in 3A illustrated embodiment, the bundles arranged spirals 26 in a housing 42 used, so that the filter device is completed. The filtered in the filtration by closing the gap solid or dirt particles are in an outside of the filter device at the bottom of the housing 42 arranged, so-called sludge collection room 56 collected and can by opening the drain plug 58 be removed.

In the embodiment according to the 4A is the mud collection room 60 for receiving the dirt particles within the filter device and can after removal of the same from the tank 40 by opening the drain plug 62 be emptied.

Of the gap filter according to the invention can, for example, for the solid / liquid separation, e.g. during sludge dewatering or solids separation from liquids, i.a. in mining, Hydraulics, paper industry, chemical industry, recycling and be applied in the municipal area. Other possible applications are the gas filtration as well as the sorting and classification of Granules and the like Grain mixtures.

in the In contrast to welded wire grids used in known split filters, the one wanted change prevent the gap width, can according to the invention by very tight (small) winding ratio D / d and dense (initial gap width 0) Spiraling the profile wire with a preferably "skimpy", that is, not quite semicircular profile, similar to one Bowden cable or a Zugfederstranges, both on the elaborate support profiles be omitted (self-supporting gap filter), as well as a stepless, uniform gap width change through easy stretching of the helix can be achieved.

By the possibility, Automata for tension spring manufacture in the manufacture of the filters according to the invention to use the filter devices according to the invention considerably cheaper to be produced.

in the Unlike traditional Split filters, in which elaborate, separate devices for cleaning the cylindrical gap filter can be used completely omitted according to the invention, because the cleaning by lifting the spiral extension and thus the closing the filter gap is made.

Of the gap filter according to the invention shows a low volume of construction in relation to the filter surface, which considerably cheaper is and by bundle arrangement many coils to even larger filter surfaces lead small volume can.

Claims (28)

Filter device for filtering aid-free filtration of media to be filtered, wherein a coiled profile wire ( 14 . 20 ) is used, which can be traversed in the radial direction by the medium to be filtered in the axial and axial column of the coiled profile wire, characterized in that the profile wire is an elastic-plastic wire with a dimensionally stable, self-supporting, longitudinally biased cylindrical structure. Filter device according to claim 1, characterized in that the gap width over the entire length of the coiled profile wire ( 14 . 20 ) is uniformly variable. Filter device according to claim 1 or 2, characterized in that the coiled profile wire ( 14 . 20 ) has a winding ratio w in the range of 3 to 20, wherein the winding ratio w is defined as the quotient of the mean winding diameter D and the maximum radial profile dimension d. Filter device according to claim 3, characterized in that that the winding ratio w is in the range of 5.5 to 7.5. Filter device according to one of the preceding Claims, characterized in that the profile wire is a steel wire or consists of a metal with resilient properties. Filter device according to one of the preceding claims, characterized in that the profile wire in the helical longitudinal direction has a larger cross section as in the radial direction. Filter device according to one of the preceding claims, characterized characterized in that the profile wire is an oval or polygonal, preferably simply symmetrical conical cross-section. Filter device according to one of the preceding claims, characterized characterized in that the profile wire has a nearly semicircular cross-section having. Filter device according to one of the preceding claims, characterized in that the profile wire has a two-edge profile. Filter device according to one of the preceding claims, characterized characterized in that the gap in the flow direction a positive taper having. Filter device according to one of the preceding claims, characterized characterized in that the initial gap in the range of 0 to 3 mm is variable. Filter device according to one of the preceding claims, characterized characterized in that it is self-cleaning. Filter device according to one of the preceding claims, characterized in that a plurality of coiled profiled wires ( 14 . 20 ) to a filter pack ( 26 ) is summarized. Filter device according to claim 13, characterized in that the filter bundles ( 26 ) on both sides non-positive and media-tight connections ( 28 ) exhibit. Filter device according to claim 13 or 14, characterized in that the filter pack ( 26 ) of a housing ( 42 ) are enclosed. Filter device according to claim 13 or 14, characterized in that the filter pack ( 26 ) into a liquid tank ( 40 ) is used. Filter device according to claim 16, characterized in that that the liquid tank an oil tank is. Filter device according to one of the preceding claims, characterized in that it comprises a collecting space ( 56 . 60 ) for filtered dirt particles. Filter device according to claim 18, characterized in that the collecting space ( 60 ) is disposed within the filter device. Filter device according to claim 18, characterized in that the collecting space ( 56 ) is arranged outside the filter device. Filter device according to one of claims 18 to 20, characterized in that the collecting spaces ( 56 . 60 ) each a drain plug ( 58 . 62 ) for emptying the plenum. Method for filtering aid-free filtration of media to be filtered with a filter device according to one of claims 1 to 21, characterized in that by longitudinal stretching of the individual or bundle-mounted profile wire helix ( 14 . 20 ) takes place over the helix length uniform, wegproportionale gap opening. Method according to claim 22, characterized in that that depending on the gap orientation, a filtration from the outside to inside or inside out carried out becomes. A method according to claim 22 or 23, characterized in that by closing the gap when relaxing the coil ( 14 . 20 ) an automatic cleaning of solid particles takes place. Method according to one of claims 22 to 24, characterized that the gap opening through the dynamic pressure of the medium to be filtered is effected. Method according to one of claims 22 to 25, characterized that the gap after completion of the volume flow of the filtered Medium automatically closes. Method according to one of claims 22 to 26, characterized in that the gap width adjustment by changing the length of the coil ( 14 . 20 ) by means of an adjusting spindle ( 52 ) and a rotary knob ( 54 ) he follows. Use of the filter device according to one of claims 1 to 21 as a diffuser to calm the return flow in a liquid tank.