EP4351758A1 - Folded filter medium - Google Patents

Folded filter medium

Info

Publication number
EP4351758A1
EP4351758A1 EP22727279.6A EP22727279A EP4351758A1 EP 4351758 A1 EP4351758 A1 EP 4351758A1 EP 22727279 A EP22727279 A EP 22727279A EP 4351758 A1 EP4351758 A1 EP 4351758A1
Authority
EP
European Patent Office
Prior art keywords
filter medium
embossings
embossing
filter
substrate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22727279.6A
Other languages
German (de)
French (fr)
Inventor
Dennis Stark
Tatiana KLOFT
Andreas Pelz
Joachim Stinzendörfer
Andreas Beck
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mann and Hummel GmbH
Original Assignee
Mann and Hummel GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mann and Hummel GmbH filed Critical Mann and Hummel GmbH
Publication of EP4351758A1 publication Critical patent/EP4351758A1/en
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/14—Other self-supporting filtering material ; Other filtering material
    • B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
    • B01D39/1692—Other shaped material, e.g. perforated or porous sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/52—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material
    • B01D46/521—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material using folded, pleated material
    • B01D46/522—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material using folded, pleated material with specific folds, e.g. having different lengths
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/14—Other self-supporting filtering material ; Other filtering material
    • B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
    • B01D39/18—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being cellulose or derivatives thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D63/00—Apparatus in general for separation processes using semi-permeable membranes
    • B01D63/06—Tubular membrane modules
    • B01D63/067—Tubular membrane modules with pleated membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/10—Supported membranes; Membrane supports
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/04—Additives and treatments of the filtering material
    • B01D2239/0464—Impregnants
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/04—Additives and treatments of the filtering material
    • B01D2239/0471—Surface coating material
    • B01D2239/0478—Surface coating material on a layer of the filter
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/065—More than one layer present in the filtering material
    • B01D2239/0654—Support layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/065—More than one layer present in the filtering material
    • B01D2239/0668—The layers being joined by heat or melt-bonding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/065—More than one layer present in the filtering material
    • B01D2239/0681—The layers being joined by gluing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/08—Special characteristics of binders
    • B01D2239/083—Binders between layers of the filter
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/10—Filtering material manufacturing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/0001—Making filtering elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/10—Particle separators, e.g. dust precipitators, using filter plates, sheets or pads having plane surfaces
    • B01D46/106—Ring-shaped filtering elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/52—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material
    • B01D46/521—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material using folded, pleated material
    • B01D46/523—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material using folded, pleated material with means for maintaining spacing between the pleats or folds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/66—Regeneration of the filtering material or filter elements inside the filter
    • B01D46/70—Regeneration of the filtering material or filter elements inside the filter by acting counter-currently on the filtering surface, e.g. by flushing on the non-cake side of the filter
    • B01D46/71—Regeneration of the filtering material or filter elements inside the filter by acting counter-currently on the filtering surface, e.g. by flushing on the non-cake side of the filter with pressurised gas, e.g. pulsed air
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/08—Polysaccharides
    • B01D71/10—Cellulose; Modified cellulose
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/30—Polyalkenyl halides
    • B01D71/32—Polyalkenyl halides containing fluorine atoms
    • B01D71/36—Polytetrafluoroethene

Definitions

  • the invention relates to a pleated filter medium, a filter element, a filter arrangement, a vehicle and a manufacturing method for a pleated filter medium.
  • Known pleated filter media which are used in particular in air filters of vehicles, have an inflow side and an outflow side.
  • the dust particles accumulate on the inflow side of the filter medium. Due to the accumulation of the dust particles, the pressure conditions between the inflow and outflow side change during operation such that a pressure loss between them increases. This increase can cause the pleats of the filter media to collapse or bunch up. As a result, the remaining, still open folds have higher filtration speeds (ratio of the air volume flow to the filter surface) than specified by the manufacturer, so that they become clogged with dust particles even more quickly.
  • the filter medium In order to counteract the adverse effects described above, the filter medium must either be replaced or cleaned regularly. Cleaning can be carried out using various techniques, such as shaking, shaking, tapping, flushing or brief countercurrent pressure pulses.
  • Filter elements with good detachability are known from the prior art, which include a cellulose substrate with an ePTFE layer (expanded polytetrafluoroethylene) arranged thereon.
  • the ePTFE layer is typically on the upstream side of the filter media. It has a low adhesive force and therefore a reversible particle deposit, which simplifies the cleaning of the filter medium.
  • the cellulose substrate has a high level of mechanical stability.
  • thermoplastic resins also known as thermoplastics.
  • WO 2006/012495 A1 discloses a filter medium comprising a cellulose substrate impregnated with polyvinyl acetate (PVA) to which an ePTFE sheet is laminated.
  • PVA polyvinyl acetate
  • thermoplastic materials are softer at elevated temperatures and are therefore easily deformable.
  • the object of the invention is to create an improved filter medium.
  • a pleated filter medium which comprises a cellulosic substrate with an ePTFE layer disposed thereon.
  • the cellulose substrate is impregnated with phenolic resin.
  • a pleated filter medium is to be understood as meaning a filter medium which has folds.
  • the pleated filter media can have different shapes.
  • the pleated filter medium can be designed to be planar, cylindrical or conical, with the cross section of the cylindrical or conical filter medium being able to be particularly circular or oval.
  • the cellulose substrate of the folded filter medium ensures mechanical stability.
  • the cellulose substrate forms the downstream side of the filter medium.
  • the downstream side is the side of the filter medium from which the cleaned fluid exits.
  • the ePTFE layer which can be designed as a membrane, is arranged on the inflow side of the filter medium on the cellulose substrate.
  • the upstream side of the filter medium is the side through which the fluid to be filtered enters the filter medium.
  • the ePTFE layer exhibits lower adhesion to dust particles and reversible particle deposition.
  • the cellulosic substrate is advantageously impregnated with a phenolic resin in the present case.
  • Phenolic resin is a thermosetting polymer, also known as thermoset or duromer. Thermosets can no longer be deformed after they have been hardened by heating. In contrast to thermoplastics, they are dimensionally stable even at elevated temperatures.
  • the use of the phenolic resin as an impregnating agent is also particularly suitable for use in a filter medium due to its hydrophobic character.
  • the phenolic resin impregnated into the cellulosic substrate also serves as a binder for the ePTFE layer.
  • the pleated filter medium is more dimensionally stable after the phenolic resin has cured. This prevents the folds from collapsing, especially when the filter medium is cleaned using the countercurrent principle.
  • the ePTFE sheet is laminated to the cellulosic substrate.
  • Lamination is meant here as the application of the ePTFE layer to the phenolic resin impregnated cellulosic substrate through the application of pressure.
  • Lamination can be warm or cold: In warm laminating, in addition to pressure, heat is also applied to improve the adhesion of the ePTFE layer to the cellulosic substrate. Lamination improves the adhesion of the ePTFE layer to the cellulosic substrate.
  • the filter medium has folds which each have at least one embossing or one groove.
  • Embossing means a modification of the fold surface. This modification can be a (local) elevation or depression in the fold wall. However, an embossing can also be an indentation at the tip of the fold or at the bottom of the fold. Embossing advantageously stiffens a fold. A fold can have several embossings.
  • the embossing of two adjacent folds can be arranged in such a way that an area is defined between the two folds in which they do not touch. This can prevent two adjacent folds from collapsing onto one another in such a way that air can no longer flow between them.
  • the embossing of two adjacent folds can be at least partially opposite. This makes it even better to prevent two adjacent folds from collapsing on one another.
  • the embossing can be knobs and/or S embossing and/or pleat lock embossing.
  • Nubs are elevations on the fold wall. They can have different shapes. For example, they can be round, oval or rectangular.
  • S embossings are S-shaped indentations or bulges that extend from just below the tip of the fold to the bottom of the fold. Both nub and S-embossing are advantageous in that they serve to stiffen the pleat wall. Knob and/or S embossing can also be arranged on two adjacent folds in such a way that the embossing is at least partially opposite, in such a way that they define an area in which the two adjacent folds do not touch.
  • Pleat-lock embossings are depressions at the top or bottom of the fold. Pleat-lock embossing is advantageous in that it is particularly effective at keeping the fold tips or fold bottoms of adjacent folds apart. This prevents the folds from collapsing on one another in a particularly effective manner. Pleat lock embossing is preferably located at the pleat tip.
  • At least one fold has at least two pleat lock embossings, with at least one S embossing or one knob embossing being provided between the two pleat lock embossings.
  • the fold wall can be stiffened and the folds can be prevented from being stacked at the same time.
  • each fold has identical embossments.
  • a filter element is provided with a pleated filter medium as described above.
  • the filter element has at least the filter medium and a sealing arrangement for sealing between the raw side and the clean side.
  • this can be a surrounding frame, for example.
  • the filter element is preferably designed as a hollow cylinder or as a conical shape.
  • the filter medium is closed in the form of a ring, for example by welding or gluing the end folds of a filter medium section. End plates for sealing are arranged on the opposite end faces.
  • the filter element can furthermore have a support tube, in particular a cage-like one, with the filter medium being arranged around the support tube.
  • the outside preferably forms the inflow side or raw side and the inside the outflow side or clean side.
  • the filter element is in particular a filter element for an air filter.
  • the air filter can be an intake air filter.
  • a filter assembly includes a housing in which a filter element described above is accommodated.
  • the filter medium of the filter element can be cleaned using the countercurrent principle.
  • Means are provided for this purpose, which serve to generate pressure pulses that produce a pressure difference between the outflow and the inflow side of the filter medium. These pressure pulses allow the dust particles that have accumulated on the inflow side of the ePTFE layer of the filter medium to be removed from it again.
  • a vehicle is provided with a filter element as described above or with a filter arrangement as described above.
  • the vehicle is in particular an agricultural utility vehicle, such as a combine harvester or a tractor.
  • agricultural utility vehicle such as a combine harvester or a tractor.
  • Motor vehicles, trucks, construction vehicles, watercraft or aircraft are also possible.
  • a method for producing a filter medium as described above is provided.
  • the cellulosic substrate is first impregnated with a phenolic resin.
  • an ePTFE layer is applied to the cellulose substrate.
  • the impregnated cellulose substrate with the ePFTE layer applied thereto is then folded.
  • the phenolic resin is then cured to stiffen the filter media pleats and bond the ePFTE layer to the cellulosic substrate.
  • the phenolic resin is preferably cured by the introduction of heat.
  • the embossments are made in the folds of the cellulosic substrate.
  • the ePTFE layer is applied to the cellulose substrate by lamination.
  • the lamination of the ePTFE sheet to the cellulosic substrate is preferably accomplished through the application of pressure and/or temperature.
  • the ePTFE layer is applied to the cellulosic substrate first, then the cellulosic substrate with the ePTFE layer applied thereto is passed through preheated rollers.
  • FIG. 1 is a perspective view of a filter assembly according to one embodiment
  • Fig. 2 shows a section along line A-A of Fig. 1;
  • Figure 3 is a perspective view of a section of pleated filter media
  • Figure 4 is a section along line B-B of Figure 3;
  • FIG. 6 shows a schematic representation of a manufacturing method for a filter medium
  • the filter arrangement 1 shows a perspective view of an embodiment of a filter arrangement 1.
  • the filter arrangement 1 can also be referred to as a filter system. You will find application as an intake air filter for internal combustion engines for agricultural purposes, such as a combine harvester.
  • the filter arrangement 1 has a housing 2 in which a filter element 3 is accommodated, as can be seen from FIG.
  • the housing 2 also has a fluid inlet 4 and a fluid outlet 5 .
  • the fluid to be filtered in this case the intake air L, enters the filter assembly 1 through the fluid inlet 4 .
  • the intake air L′ cleaned by the filter element 3 exits the filter arrangement 1 through the fluid outlet 5 .
  • the filter element 3 has a folded filter medium 6 which surrounds a support tube 7 and rests against it in such a way that the support tube 7 can perform a supporting function for the filter medium 6 when it is flowed through.
  • the support tube 7 is in the form of a lattice and is therefore designed to be fluid-permeable.
  • the filter element 3, the filter medium 6 and the support tube 7 are designed in the embodiment form according to FIGS. 1 and 2 cylindrical with a circular cross-section. However, it is also conceivable for the filter element 3, the filter medium 6 and the support tube 7 to have a different cross section, for example an oval cross section, and/or to be conical. A planar design is also possible.
  • the air L to be filtered passes from a raw side RO of the filter element 3 through the filter medium 6 and emerges as cleaned air L′ on a clean side RL of the filter element 3 surrounded by the support tube 7 .
  • the raw side RO is in fluid communication with the fluid inlet 4 and the clean side RL is in fluid communication with the fluid outlet RL.
  • the filter medium 6 has an inflow side 8 and an outflow side 9 .
  • the inflow side 8 is the side of the filter medium 6 facing the raw side RO of the filter element 3.
  • the outflow side 9 is the side of the filter medium 6 facing the clean side RL of the filter element 3.
  • the dust particles contained in the air L to be filtered are accumulated on the inflow side 8 of the filter medium 6, so that the filter medium 6 is loaded. After a certain time, however, the loading of the filter medium 6 is so high that the pressure loss between its inflow side 8 and outflow side 9 increases to such an extent that the filter element 3 has to be replaced or the filter medium 6 has to be cleaned.
  • the filter arrangement 1 has means 10, 11 which are used to clean the filter medium 6 in the countercurrent principle.
  • the means 10, 11 are tubes 12, 13 which open into the clean side RL of the filter element 3 at ends 14, 15 and at ends 14, 15 opposite ends 16,17 can be connected to a compressed air source not shown in detail here are.
  • valves 18, 19 are provided for generating pressure surges.
  • the filter medium 6 is a pleated filter medium, as can be seen from FIG. This shows a perspective view of a section of the folded filter medium 6 with folds 20, wherein only one fold 20 is shown completely in FIG.
  • Each fold 20 has two fold walls 21, with adjacent walls 21 being connected to each other on the upstream side at a common fold tip 22 - also called the upper fold edge - and on the downstream side at a common fold base 23 - also called the lower fold edge.
  • the fold walls 21 have both S embossings 24 and nub embossings 25 .
  • the S embossings 24 are indentations or bulges that extend from just below the tip 22 of the fold to the bottom 23 of the fold.
  • a fold wall 21 has several S embossings 24 .
  • the S embossings 24 are S-shaped and arranged in such a way that two S embossings arranged on two adjacent fold walls 21 Embossings 24 are performed symmetrically. This defines a region 26 between the S embossings 24 in which the two fold walls 21 do not touch.
  • the embossed knobs 25 are bulges on the inflow side 8 of the fold wall 21 .
  • Each of the fold walls 21 has a plurality of embossed knobs 25 .
  • the embossed knobs 25 are also arranged in such a way that two embossed knobs 25 arranged on two adjacent fold walls 21 are symmetrical. As a result, a region 27 is defined between the embossed knobs 25 in which the two fold walls 21 do not touch.
  • pleat-lock embossings 28 are also provided. These are indentation points that serve to keep the fold tips 22 of adjacent folds 20 apart.
  • Fig. 4 shows a section along the line B-B of Fig. 3.
  • the knob embossings 25, S embossings 24 and pleat lock embossings 28 can be seen.
  • Fig. 5 shows a layered structure of the filter medium 6.
  • the filter medium 6 comprises a cellulose substrate 29 which is impregnated with a phenolic resin 30 and an ePTFE layer 31 arranged on the cellulose substrate 29.
  • the cellulose substrate 29 ensures the mechanical stability of the filter medium 6 .
  • the cellulose substrate 29 is arranged on the outflow side 9 of the filter medium 6 .
  • the ePTFE layer 31 which can also be applied to the cellulose substrate 29 as a membrane, is arranged on the inflow side 8 of the filter medium 6.
  • the ePTFE layer 31 serves as a top filtration layer for the filter medium 6, dust particles being deposited on it.
  • the ePTFE layer 31 also has a lower adhesive force and therefore a reversible particle deposit, so that the cleaning of the filter medium is simplified using the countercurrent principle.
  • the ePFTE layer 31 is laminated onto the cellulose substrate 29 .
  • the phenolic resin 30 with which the cellulose substrate 29 is impregnated also serves as a binding agent between the cellulose substrate 29 and the ePTFE layer 31.
  • the phenolic resin 30 can no longer be deformed by the action of heat after it has hardened. The risk of a fold collapse is reduced both during normal operation of the filter arrangement 1 and during cleaning operation using the countercurrent principle.
  • Fig. 6 shows schematically a manufacturing process for producing the pleated filter medium 6.
  • a cellulose substrate 29 is impregnated with phenolic resin 30.
  • the phenolic resin 30 consists of a mixture of a basic component and a crosslinking agent, which are weighted in relation to one another in certain ways that are known to those skilled in the art.
  • the ePTFE sheet 31 is placed on the cellulosic substrate 29 (step S2).
  • the ePTFE layer 31 can be placed on the cellulosic substrate 29 by a variety of methods.
  • lamination comes into question as a method.
  • the ePTFE layer 31 is applied to the cellulose substrate 29 and the cellulose substrate 29 with the ePTFE layer 31 applied thereto is then pressed together by means of rollers.
  • the rollers can be preheated to improve the adhesion of the ePTFE layer 31 to the cellulosic substrate 29. In this case one speaks of hot lamination. If the rolls are not preheated, one speaks of cold lamination.
  • step S3 of the method the cellulosic substrate 29 with the ePTFE layer 31 attached thereto is folded.
  • the folds 20 can be embossed. These are S or nub embossings 24, 25, which are embossed into a fold wall 21, or pleat-lock embossing 28, in which fold tips 22 are pressed in.
  • the phenolic resin 30 is cured (step S5).
  • phenolic resin is cured under the action of heat.
  • the hardening of the Phe nolharzes 30 is on the one hand the cellulose substrate 29, and therefore the filter medium 6, stiff fer.
  • the ePTFE layer 31 is connected to the cellulose substrate 29 .
  • the filter medium can be applied to a support tube and provided with end plates, with the end folds being connected to one another to form the hollow body.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Filtering Materials (AREA)
  • Filtering Of Dispersed Particles In Gases (AREA)
  • Absorbent Articles And Supports Therefor (AREA)

Abstract

The invention relates to a folded filter medium (6) for a filter element (3) comprising a cellulose substrate (29) impregnated with phenolic resin (30) and an ePTFE layer (31) disposed on the cellulose substrate (29).

Description

Beschreibung description
Gefaltetes Filtermedium Pleated filter medium
Technisches Gebiet technical field
Die Erfindung betrifft ein gefaltetes Filtermedium, ein Filterelement, eine Filteranord nung, ein Fahrzeug sowie ein Herstellungsverfahren für ein gefaltetes Filtermedium.The invention relates to a pleated filter medium, a filter element, a filter arrangement, a vehicle and a manufacturing method for a pleated filter medium.
Stand der Technik State of the art
Bekannte gefaltete Filtermedien, die insbesondere in Luftfiltern von Fahrzeugen einge setzt werden, weisen eine Anströmseite und eine Abströmseite auf. Auf der Anströmsei- te des Filtermediums lagern sich die Staubpartikeln an. Aufgrund der Anlagerung der Staubpartikel ändern sich im laufenden Betrieb die Druckverhältnisse zwischen der An- und der Abströmseite dahingehend, dass ein Druckverlust zwischen diesen ansteigt. Dieser Anstieg kann zum Kollabieren bzw. Paketieren der Falten des Filtermediums führen. Folglich kommt es bei den restlichen, noch offenen Falten zu höheren Filtrati onsgeschwindigkeiten (Verhältnis des Luftvolumenstroms zu der Filterfläche) als vom Hersteller spezifiziert, so dass sich diese noch schneller mit Staubpartikeln zusetzen.Known pleated filter media, which are used in particular in air filters of vehicles, have an inflow side and an outflow side. The dust particles accumulate on the inflow side of the filter medium. Due to the accumulation of the dust particles, the pressure conditions between the inflow and outflow side change during operation such that a pressure loss between them increases. This increase can cause the pleats of the filter media to collapse or bunch up. As a result, the remaining, still open folds have higher filtration speeds (ratio of the air volume flow to the filter surface) than specified by the manufacturer, so that they become clogged with dust particles even more quickly.
Um den oben beschriebenen nachteiligen Effekten entgegenzuwirken, muss das Filter medium entweder regelmäßig ersetzt oder gereinigt werden. Die Reinigung kann durch den Einsatz verschiedener Techniken, wie beispielweise Schütteln, Rütteln, Klopfen, Durchspülen oder kurzzeitige Gegenstrom-Druckimpulse, erfolgen. In order to counteract the adverse effects described above, the filter medium must either be replaced or cleaned regularly. Cleaning can be carried out using various techniques, such as shaking, shaking, tapping, flushing or brief countercurrent pressure pulses.
Unabhängig von der Technik, die zum Reinigen eingesetzt wird, ist es wichtig, dass das Filtermedium eine gute Abreinigbarkeit aufweist, um eine irreversible Partikelanlagerung zu vermeiden. Aus dem Stand der Technik sind Filterelemente mit einer guten Abrei nigbarkeit bekannt, die ein Zellulosesubstrat mit einer darauf angeordneten ePTFE- Lage (expandiertes Polytetrafluorethylen) umfassen. Die ePTFE-Lage befindet sich normalerweise auf der Anströmseite des Filtermediums. Sie weist eine geringe Haftkraft und daher eine reversible Partikelablagerung auf, wodurch die Abreinigung des Filter mediums vereinfacht wird. Das Zellulosesubstrat weist eine hohe mechanische Stabili tät auf. Regardless of the technology used for cleaning, it is important that the filter medium is easy to clean in order to avoid irreversible particle accumulation. Filter elements with good detachability are known from the prior art, which include a cellulose substrate with an ePTFE layer (expanded polytetrafluoroethylene) arranged thereon. The ePTFE layer is typically on the upstream side of the filter media. It has a low adhesive force and therefore a reversible particle deposit, which simplifies the cleaning of the filter medium. The cellulose substrate has a high level of mechanical stability.
Es ist auch bekannt, die Haftung der ePTFE-Lage auf dem Zellulosesubstrat durch eine Imprägnierung desselben mit thermoplastischen Harzen, auch als Thermoplaste be kannt, zu verbessern. Die WO 2006 / 012495 A1 offenbart ein Filtermedium umfassend ein mit Polyvinylacetat (PVA) imprägniertes Zellulosesubstrat, auf dem eine ePTFE- Lage laminiert ist. It is also known to improve the adhesion of the ePTFE layer to the cellulosic substrate by impregnating it with thermoplastic resins, also known as thermoplastics. WO 2006/012495 A1 discloses a filter medium comprising a cellulose substrate impregnated with polyvinyl acetate (PVA) to which an ePTFE sheet is laminated.
Nachteilig an einer Imprägnierung des Zellulosesubstrats mit thermoplastischen Materi alien ist es, dass thermoplastische Materialien bei erhöhten Temperaturen weicher und dadurch leicht verformbar sind. A disadvantage of impregnating the cellulose substrate with thermoplastic materials is that thermoplastic materials are softer at elevated temperatures and are therefore easily deformable.
Offenbarung der Erfindung Disclosure of Invention
Vor diesem Hintergrund liegt die Aufgabe der Erfindung darin, ein verbessertes Filter medium zu schaffen. Against this background, the object of the invention is to create an improved filter medium.
Demgemäß wird ein gefaltetes Filtermedium vorgeschlagen, das ein Zellulosesubstrat mit einer darauf angeordneten ePTFE-Lage umfasst. Das Zellulosesubstrat ist mit Phe nolharz imprägniert. Accordingly, a pleated filter medium is proposed which comprises a cellulosic substrate with an ePTFE layer disposed thereon. The cellulose substrate is impregnated with phenolic resin.
Unter einem gefalteten Filtermedium ist vorliegend ein Filtermedium zu verstehen, das Falten aufweist. Das gefaltete Filtermedium kann verschiedene Formen haben. Insbe sondere kann das gefaltete Filtermedium planar, zylindrisch oder konisch ausgeführt werden, wobei der Querschnitt des zylindrischen oder konischen Filtermediums insbe sondere kreisrund oder oval sein kann. In the present case, a pleated filter medium is to be understood as meaning a filter medium which has folds. The pleated filter media can have different shapes. In particular, the pleated filter medium can be designed to be planar, cylindrical or conical, with the cross section of the cylindrical or conical filter medium being able to be particularly circular or oval.
Das Zellulosesubstrat des gefalteten Filtermediums sorgt für die mechanische Stabilität. Das Zellulosesubstrat bildet die Abströmseite des Filtermediums. Die Abströmseite ist die Seite des Filtermediums, aus der das gereinigte Fluid austritt. The cellulose substrate of the folded filter medium ensures mechanical stability. The cellulose substrate forms the downstream side of the filter medium. The downstream side is the side of the filter medium from which the cleaned fluid exits.
Die ePTFE-Lage, die als Membran ausgeführt sein kann, ist auf der Anströmseite des Filtermediums auf dem Zellulosesubstrat angeordnet. Die Anströmseite des Filtermedi ums ist die Seite, durch die das zu filtrierende Fluid in das Filtermedium eintritt. Die ePTFE-Lage weist eine geringere Haftkraft gegenüber Staubpartikeln und eine reversib le Partikelablagerung auf. The ePTFE layer, which can be designed as a membrane, is arranged on the inflow side of the filter medium on the cellulose substrate. The upstream side of the filter medium is the side through which the fluid to be filtered enters the filter medium. The ePTFE layer exhibits lower adhesion to dust particles and reversible particle deposition.
Vorteilhaft wird das Zellulosesubstrat vorliegend mit einem Phenolharz imprägniert.The cellulosic substrate is advantageously impregnated with a phenolic resin in the present case.
Phenolharz ist ein duroplastisches Polymer, auch als Duroplast oder Duromer bekannt. Duromere sind nach der Aushärtung durch Erwärmung nicht mehr verformbar. Sie sind also, im Gegensatz zu Thermoplasten, auch bei erhöhten Temperaturen formstabil. Auch ist die Benutzung des Phenolharzes als Imprägnierungsmittel aufgrund seines hydrophoben Charakters für den Einsatz in einem Filtermedium besonders geeignet. Das Phenolharz, mit dem das Zellulosesubstrat imprägniert ist, dient auch als Bindemit tel für die ePTFE-Lage. Phenolic resin is a thermosetting polymer, also known as thermoset or duromer. Thermosets can no longer be deformed after they have been hardened by heating. In contrast to thermoplastics, they are dimensionally stable even at elevated temperatures. The use of the phenolic resin as an impregnating agent is also particularly suitable for use in a filter medium due to its hydrophobic character. The phenolic resin impregnated into the cellulosic substrate also serves as a binder for the ePTFE layer.
Das gefaltete Filtermedium ist nach der Aushärtung des Phenolharzes formstabiler. Dadurch wird der Faltenkollaps verhindert, gerade auch bei einer Abreinigung des Fil termediums im Gegenstromprinzip. The pleated filter medium is more dimensionally stable after the phenolic resin has cured. This prevents the folds from collapsing, especially when the filter medium is cleaned using the countercurrent principle.
Gemäß einer Ausführungsform ist die ePTFE-Lage auf das Zellulosesubstrat laminiert. Laminieren ist hier als das Aufbringen der ePTFE-Lage auf das mit Phenolharz impräg nierte Zellulosesubstrat durch die Anwendung von Druck gemeint. Das Laminieren kann warm oder kalt sein: Beim Warm laminieren wird zusätzlich zu dem Druck auch Wärme zugeführt, um die Haftung der ePTFE-Lage auf dem Zellulosesubstrat zu verbessern. Durch das Laminieren wird die Haftung der ePTFE-Lage auf dem Zellulosesubstrat ver bessert. In one embodiment, the ePTFE sheet is laminated to the cellulosic substrate. Lamination is meant here as the application of the ePTFE layer to the phenolic resin impregnated cellulosic substrate through the application of pressure. Lamination can be warm or cold: In warm laminating, in addition to pressure, heat is also applied to improve the adhesion of the ePTFE layer to the cellulosic substrate. Lamination improves the adhesion of the ePTFE layer to the cellulosic substrate.
Gemäß einer weiteren Ausführungsform weist das Filtermedium Falten auf, die jeweils zumindest eine Prägung bzw. eine Rillierung aufweisen. Unter Prägung ist eine Modifi zierung der Faltenoberfläche zu verstehen. Diese Modifizierung kann eine (lokale) Er hebung bzw. Vertiefung in der Faltenwand sein. Eine Prägung kann aber auch eine Eindrückstelle an der Faltenspitze oder an dem Faltengrund sein. Prägungen versteifen eine Falte vorteilhaft. Eine Falte kann mehrere Prägungen aufweisen. According to a further embodiment, the filter medium has folds which each have at least one embossing or one groove. Embossing means a modification of the fold surface. This modification can be a (local) elevation or depression in the fold wall. However, an embossing can also be an indentation at the tip of the fold or at the bottom of the fold. Embossing advantageously stiffens a fold. A fold can have several embossings.
Alternativ oder zusätzlich können die Prägungen von zwei benachbarten Falten derart angeordnet sein, dass ein Bereich zwischen den zwei Falten definiert ist, in dem sich diese nicht berühren. Dadurch kann vermieden werden, dass zwei benachbarte Falten derart aufeinander kollabieren, dass keine Luft mehr zwischen ihnen strömen kann.Alternatively or additionally, the embossing of two adjacent folds can be arranged in such a way that an area is defined between the two folds in which they do not touch. This can prevent two adjacent folds from collapsing onto one another in such a way that air can no longer flow between them.
Gemäß einer Ausführungsform können sich die Prägungen zwei benachbarter Falten zumindest teilweise gegenüberliegen. Dadurch kann noch besser verhindert werden, dass zwei benachbarte Falten aufeinander kollabieren. According to one embodiment, the embossing of two adjacent folds can be at least partially opposite. This makes it even better to prevent two adjacent folds from collapsing on one another.
Bei den Prägungen kann es sich um Noppen und/oder S-Prägungen und/oder Pleat- Lock-Prägungen handeln. The embossing can be knobs and/or S embossing and/or pleat lock embossing.
Noppen sind Erhebungen auf der Faltenwand. Sie können verschiedenen Formen ha ben. Beispielweise können sie rund, oval oder rechteckig sein. Nubs are elevations on the fold wall. They can have different shapes. For example, they can be round, oval or rectangular.
S-Prägungen sind S-förmig ausgestaltete Ein- bzw. Ausbuchtungen, die von kurz unter halb der Faltenspitze bis zu dem Faltengrund reichen. Sowohl Noppen- als auch S-Prägungen sind dahingehend vorteilhaft, dass sie dazu dienen, die Faltenwand zu versteifen. Auch können Noppen- und/oder S-Prägungen auf zwei benachbarten Falten derart angeordnet werden, dass sich die Prägungen zumin dest teilweise gegenüberliegen, und zwar derart, dass sie einen Bereich definieren, in dem sich die zwei benachbarten Falten nicht berühren. S embossings are S-shaped indentations or bulges that extend from just below the tip of the fold to the bottom of the fold. Both nub and S-embossing are advantageous in that they serve to stiffen the pleat wall. Knob and/or S embossing can also be arranged on two adjacent folds in such a way that the embossing is at least partially opposite, in such a way that they define an area in which the two adjacent folds do not touch.
Pleat-Lock-Prägungen sind Eindrückstellen an der Faltenspitze oder an dem Falten grund. Pleat-Lock-Prägungen sind dahingehend vorteilhaft, dass sie die Faltenspitzen oder Faltengrunde benachbarter Falten besonders effektiv auseinanderhalten können. Dadurch wird das Kollabieren der Falten aufeinander besonders wirksam vermieden. Pleat-Lock-Prägungen befinden sich vorzugsweise an der Faltenspitze. Pleat-lock embossings are depressions at the top or bottom of the fold. Pleat-lock embossing is advantageous in that it is particularly effective at keeping the fold tips or fold bottoms of adjacent folds apart. This prevents the folds from collapsing on one another in a particularly effective manner. Pleat lock embossing is preferably located at the pleat tip.
Nach einer Ausführungsform weist zumindest eine Falte zumindest zwei Pleat-Lock- Prägungen auf, wobei zwischen den zwei Pleat-Lock-Prägungen zumindest eine S- Prägung oder eine Noppenprägung vorgesehen ist. Dadurch können gleichzeitig die Versteifung der Faltenwand sowie das Vermeiden der Paketierung der Falten erreicht werden. According to one embodiment, at least one fold has at least two pleat lock embossings, with at least one S embossing or one knob embossing being provided between the two pleat lock embossings. As a result, the fold wall can be stiffened and the folds can be prevented from being stacked at the same time.
Nach einerweiteren Ausführungsform weist jede Falte identische Prägungen auf. According to another embodiment, each fold has identical embossments.
Gemäß einem weiteren Aspekt wird ein Filterelement mit einem vorstehend beschrie benen gefalteten Filtermedium bereitgestellt. Das Filterelement weist zumindest das Filtermedium und eine Dichtanordnung zur Abdichtung zwischen Rohseite und Reinsei te auf. Im Fall eines flachen Filterelements kann dies beispielsweise ein umlaufender Rahmen sein. Vorzugsweise ist das Filterelement als Hohlzylinder oder konisch ausge führt. Das Filtermedium ist hierzu ringförmig geschlossen ausgeführt, beispielsweise durch Verschweißen oder Verkleben der Endfalten eines Filtermediumabschnitts. An den gegenüberliegenden Stirnseiten sind Endscheiben zur Abdichtung angeordnet. Das Filterelement kann weiterhin ein insbesondere käfigartiges Stützrohr aufweisen, wobei das Filtermedium um das Stützrohr herum angeordnet ist. Vorzugsweise bildet die Au ßenseite die Anströmseite bzw. Rohseite und die Innenseite die Abströmseite bzw. Reinseite. According to a further aspect, a filter element is provided with a pleated filter medium as described above. The filter element has at least the filter medium and a sealing arrangement for sealing between the raw side and the clean side. In the case of a flat filter element, this can be a surrounding frame, for example. The filter element is preferably designed as a hollow cylinder or as a conical shape. For this purpose, the filter medium is closed in the form of a ring, for example by welding or gluing the end folds of a filter medium section. End plates for sealing are arranged on the opposite end faces. The filter element can furthermore have a support tube, in particular a cage-like one, with the filter medium being arranged around the support tube. The outside preferably forms the inflow side or raw side and the inside the outflow side or clean side.
Bei dem Filterelement handelt es sich insbesondere um ein Filterelement für einen Luft filter. Bei dem Luftfilter kann es sich um einen Ansaugluftfilter handeln. The filter element is in particular a filter element for an air filter. The air filter can be an intake air filter.
Gemäß einem weiteren Aspekt wird eine Filteranordnung bereitgestellt. Diese umfasst ein Gehäuse, in dem ein vorstehend beschriebenes Filterelement aufgenommen ist. Das Filtermedium des Filterelements ist im Gegenstromprinzip abreinigbar. Hierfür sind Mittel vorgesehen, die dazu dienen, Druckimpulse zu generieren, die eine Druckdiffe renz zwischen der Ab- und der Anströmseite des Filtermediums erzeugen. Durch diese Druckimpulse können die Staubpartikel, die sich anströmseitig auf der ePTFE-Lage des Filtermediums angelagert haben, von dieser wieder entfernt werden. According to another aspect, a filter assembly is provided. This includes a housing in which a filter element described above is accommodated. The filter medium of the filter element can be cleaned using the countercurrent principle. Means are provided for this purpose, which serve to generate pressure pulses that produce a pressure difference between the outflow and the inflow side of the filter medium. These pressure pulses allow the dust particles that have accumulated on the inflow side of the ePTFE layer of the filter medium to be removed from it again.
Gemäß einem weiteren Aspekt wird ein Fahrzeug mit einem wie vorstehend beschrie benen Filterelement oder mit einer wie vorstehend beschriebenen Filteranordnung be reitgestellt. Bei dem Fahrzeug handelt es sich insbesondere um ein landwirtschaftliches Nutzfahrzeug, wie beispielweise einen Mähdrescher oder einen Traktor. Kraftfahrzeuge, Lastkraftwagen, Baufahrzeuge, Wasserfahrzeuge oder Luftfahrzeuge kommen eben falls in Betracht. According to a further aspect, a vehicle is provided with a filter element as described above or with a filter arrangement as described above. The vehicle is in particular an agricultural utility vehicle, such as a combine harvester or a tractor. Motor vehicles, trucks, construction vehicles, watercraft or aircraft are also possible.
Gemäß einem weiteren Aspekt wird ein Verfahren zur Herstellung eines vorstehend beschriebenen Filtermediums bereitgestellt. Gemäß dem Herstellungsverfahren wird zuerst das Zellulosesubstrat mit einem Phenolharz imprägniert. Nach der Imprägnie rung wird eine ePTFE-Lage auf das Zellulosesubstrat aufgebracht. Das imprägnierte Zellulosesubstrat mit der darauf aufgebrachten ePFTE-Lage wird sodann gefaltet. An schließend wird das Phenolharz gehärtet, um die Falten des Filtermediums zu verstei fen und die ePFTE-Lage mit dem Zellulosesubstrat zu verbinden. Die Aushärtung des Phenolharzes erfolgt vorzugsweise durch die Einbringung von Wärme. According to a further aspect, a method for producing a filter medium as described above is provided. According to the manufacturing process, the cellulosic substrate is first impregnated with a phenolic resin. After impregnation, an ePTFE layer is applied to the cellulose substrate. The impregnated cellulose substrate with the ePFTE layer applied thereto is then folded. The phenolic resin is then cured to stiffen the filter media pleats and bond the ePFTE layer to the cellulosic substrate. The phenolic resin is preferably cured by the introduction of heat.
Nach einer Ausführungsform werden zwischen den Schritten des Faltens des Zellulo sesubstrats und des Härtens des Phenolharzes, die Prägungen in den Falten des Zellu losesubstrats eingeprägt. In one embodiment, between the steps of folding the cellulosic substrate and curing the phenolic resin, the embossments are made in the folds of the cellulosic substrate.
Nach einer weiteren Ausführungsform erfolgt das Aufbringen der ePTFE-Lage auf das Zellulosesubstrats durch Laminieren. Das Laminieren der ePTFE-Lage auf das Zellulo sesubstrat erfolgt vorzugsweise durch die Anwendung von Druck und/oder Temperatur.According to a further embodiment, the ePTFE layer is applied to the cellulose substrate by lamination. The lamination of the ePTFE sheet to the cellulosic substrate is preferably accomplished through the application of pressure and/or temperature.
Nach einer Ausführungsform wird die ePTFE-Lage auf das Zellulosesubstrat zuerst aufgebracht, dann wird das Zellulosesubstrat mit der darauf aufgebrachten ePTFE-Lage durch vorgeheizte Rollen geführt. In one embodiment, the ePTFE layer is applied to the cellulosic substrate first, then the cellulosic substrate with the ePTFE layer applied thereto is passed through preheated rollers.
Weitere vorteilhafte Ausgestaltungen und Aspekte der hier offenbarten Erfindung sind Gegenstand der Unteransprüche sowie der in den Figuren beschriebenen Ausführungs beispiele. Kurze Beschreibung der Zeichnungen Further advantageous refinements and aspects of the invention disclosed here are the subject matter of the dependent claims and of the exemplary embodiments described in the figures. Brief description of the drawings
Es zeigt dabei: It shows:
Fig. 1 eine perspektivische Ansicht einer Filteranordnung gemäß einer Ausführungs form; 1 is a perspective view of a filter assembly according to one embodiment;
Fig. 2 einen Schnitt entlang der Linie A-A aus der Fig. 1 ; Fig. 2 shows a section along line A-A of Fig. 1;
Fig. 3 eine perspektivische Ansicht eines Abschnitts eines gefalteten Filtermediums;Figure 3 is a perspective view of a section of pleated filter media;
Fig. 4 einen Schnitt entlang der Linie B-B aus der Fig. 3; Figure 4 is a section along line B-B of Figure 3;
Fig. 5 einen Schichtenaufbau des Filtermediums; und 5 shows a layered structure of the filter medium; and
Fig. 6 eine schematische Darstellung eines Herstellungsverfahrens für ein Filtermedium6 shows a schematic representation of a manufacturing method for a filter medium
In den Figuren sind gleiche oder funktionsgleiche Elemente mit denselben Bezugszei chen versehen worden, sofern nichts anderes angegeben ist. In the figures, elements that are the same or have the same function have been provided with the same reference symbols, unless otherwise stated.
Ausführungsform(en) der Erfindung embodiment(s) of the invention
Fig. 1 zeigt eine perspektivische Ansicht einer Ausführungsform einer Filteranordnung 1. Die Filteranordnung 1 kann auch als Filtersystem bezeichnet werden. Sie findet An wendung als Ansaugluftfilter bei Brennkraftstoffmaschinen für landwirtschaftliche Zwe cke, wie beispielweise einem Mähdrescher. Die Filteranordnung 1 weist ein Gehäuse 2 auf, in dem ein Filterelement 3 aufgenommen ist, wie dies aus der Fig. 2 ersichtlich ist.1 shows a perspective view of an embodiment of a filter arrangement 1. The filter arrangement 1 can also be referred to as a filter system. You will find application as an intake air filter for internal combustion engines for agricultural purposes, such as a combine harvester. The filter arrangement 1 has a housing 2 in which a filter element 3 is accommodated, as can be seen from FIG.
Das Gehäuse 2 weist ferner einen Fluideinlass 4 und einen Fluidauslass 5 auf. Das zu filternde Fluid, in diesem Fall die Ansaugluft L, tritt in die Filteranordnung 1 durch den Fluideinlass 4 ein. Die durch das Filterelement 3 bereinigte Ansaugluft L' tritt aus der Filteranordnung 1 durch den Fluidauslass 5 aus. The housing 2 also has a fluid inlet 4 and a fluid outlet 5 . The fluid to be filtered, in this case the intake air L, enters the filter assembly 1 through the fluid inlet 4 . The intake air L′ cleaned by the filter element 3 exits the filter arrangement 1 through the fluid outlet 5 .
Wie in Fig. 2 gezeigt, weist das Filterelement 3 ein gefaltetes Filtermedium 6 auf, das ein Stützrohr 7 umgibt und an diesem derart anliegt, dass das Stützrohr 7 eine stützen de Funktion für das Filtermedium 6 bei der Durchströmung desselben wahrnehmen kann. Das Stützrohr 7 ist gitterförmig und somit fluiddurchlässig ausgeführt. As shown in FIG. 2, the filter element 3 has a folded filter medium 6 which surrounds a support tube 7 and rests against it in such a way that the support tube 7 can perform a supporting function for the filter medium 6 when it is flowed through. The support tube 7 is in the form of a lattice and is therefore designed to be fluid-permeable.
Das Filterelement 3, das Filtermedium 6 und das Stützrohr 7 sind in der Ausführungs form gemäß Fig. 1 und 2 zylindrisch mit einem kreisförmigen Querschnitt ausgeführt. Es ist jedoch auch denkbar, dass das Filterelement 3, das Filtermedium 6 und das Stütz rohr 7 einen anderen Querschnitt, beispielsweise einen ovalen Querschnitt, aufweisen und/oder konisch ausgeführt sind. Ebenso ist eine planare Ausführung möglich. Die zu filternde Luft L tritt von einer Rohseite RO des Filterelements 3 durch das Filter medium 6 hindurch und tritt als gereinigte Luft L' an einer von dem Stützrohr 7 umgebe nen Reinseite RL des Filterelements 3 aus. Die Rohseite RO steht mit dem Fluideinlass 4 und die Reinseite RL steht mit dem Fluidauslass RL in fluidischer Verbindung. The filter element 3, the filter medium 6 and the support tube 7 are designed in the embodiment form according to FIGS. 1 and 2 cylindrical with a circular cross-section. However, it is also conceivable for the filter element 3, the filter medium 6 and the support tube 7 to have a different cross section, for example an oval cross section, and/or to be conical. A planar design is also possible. The air L to be filtered passes from a raw side RO of the filter element 3 through the filter medium 6 and emerges as cleaned air L′ on a clean side RL of the filter element 3 surrounded by the support tube 7 . The raw side RO is in fluid communication with the fluid inlet 4 and the clean side RL is in fluid communication with the fluid outlet RL.
Das Filtermedium 6 weist eine Anströmseite 8 und eine Abströmseite 9 auf. Die An- strömseite 8 ist die der Rohseite RO des Filterelements 3 zugewandte Seite des Filter mediums 6. Die Abströmseite 9 ist die der Reinseite RL des Filterelements 3 zugewand te Seite des Filtermediums 6. The filter medium 6 has an inflow side 8 and an outflow side 9 . The inflow side 8 is the side of the filter medium 6 facing the raw side RO of the filter element 3. The outflow side 9 is the side of the filter medium 6 facing the clean side RL of the filter element 3.
Die Staubpartikel, die in der zu filternden Luft L enthalten sind, werden an der Anström seite 8 des Filtermediums 6 angelagert, so dass das Filtermedium 6 beladen wird. Nach einer bestimmten Zeit ist die Beladung des Filtermediums 6 jedoch so hoch, dass sich der Druckverlust zwischen dessen Anströmseite 8 und Abströmseite 9 derart erhöht, dass das Filterelement 3 ersetzt oder das Filtermedium 6 gereinigt werden muss. The dust particles contained in the air L to be filtered are accumulated on the inflow side 8 of the filter medium 6, so that the filter medium 6 is loaded. After a certain time, however, the loading of the filter medium 6 is so high that the pressure loss between its inflow side 8 and outflow side 9 increases to such an extent that the filter element 3 has to be replaced or the filter medium 6 has to be cleaned.
Die Filteranordnung 1 weist Mittel 10, 11 auf, die zur Reinigung des Filtermediums 6 im Gegenstromprinzip dienen. Bei den Mitteln 10, 11 handelt es sich um Rohre 12, 13, die an Enden 14, 15 in die Reinseite RL des Filterelementes 3 münden und an den Enden 14, 15 entgegengesetzten Enden 16,17 an eine hier nicht näher gezeigten Druckluft quelle anschließbar sind. An den Enden 14, 15 der Rohre 12, 13 sind Ventile 18, 19 zur Erzeugung von Druckstößen vorgesehen. The filter arrangement 1 has means 10, 11 which are used to clean the filter medium 6 in the countercurrent principle. The means 10, 11 are tubes 12, 13 which open into the clean side RL of the filter element 3 at ends 14, 15 and at ends 14, 15 opposite ends 16,17 can be connected to a compressed air source not shown in detail here are. At the ends 14, 15 of the tubes 12, 13 valves 18, 19 are provided for generating pressure surges.
Bei dem Filtermedium 6 handelt es sich um ein gefaltetes Filtermedium, wie dies aus Fig. 3 ersichtlich ist. Diese zeigt eine perspektivische Ansicht eines Abschnitts des ge falteten Filtermediums 6 mit Falten 20, wobei in Fig. 3 nur eine Falte 20 vollständig ge zeigt ist. Jede Falte 20 weist zwei Faltenwände 21 auf, wobei jeweils benachbarte Fal tenwände 21 miteinander anströmseitig an einer gemeinsamen Faltenspitze 22 - auch obere Faltenkante genannt - und abströmseitig an einem gemeinsamen Faltengrund 23 - auch untere Faltenkante genannt - miteinander verbunden sind. The filter medium 6 is a pleated filter medium, as can be seen from FIG. This shows a perspective view of a section of the folded filter medium 6 with folds 20, wherein only one fold 20 is shown completely in FIG. Each fold 20 has two fold walls 21, with adjacent walls 21 being connected to each other on the upstream side at a common fold tip 22 - also called the upper fold edge - and on the downstream side at a common fold base 23 - also called the lower fold edge.
Die Faltenwände 21 weisen in diesem Ausführungsbeispiel sowohl S-Prägungen 24 als auch Noppenprägungen 25 auf. In this exemplary embodiment, the fold walls 21 have both S embossings 24 and nub embossings 25 .
Bei den S-Prägungen 24 handelt es sich um Ein- bzw. Ausbuchtungen, die von kurz unterhalb der Faltenspitze 22 bis zum Faltengrund 23 reichen. Eine Faltenwand 21 weist mehrere S-Prägungen 24 auf. Die S-Prägungen 24 sind S-förmig ausgestaltet und derart angeordnet, dass zwei an zwei benachbarten Faltenwänden 21 angeordnete S- Prägungen 24 symmetrisch ausgeführt sind. Dadurch wird zwischen den S-Prägungen 24 ein Bereich 26 definiert, in dem sich die zwei Faltenwände 21 nicht berühren. The S embossings 24 are indentations or bulges that extend from just below the tip 22 of the fold to the bottom 23 of the fold. A fold wall 21 has several S embossings 24 . The S embossings 24 are S-shaped and arranged in such a way that two S embossings arranged on two adjacent fold walls 21 Embossings 24 are performed symmetrically. This defines a region 26 between the S embossings 24 in which the two fold walls 21 do not touch.
Bei den Noppenprägungen 25 handelt es sich um Ausbuchtungen auf der Anströmseite 8 der Faltenwand 21 Jede der Faltenwände 21 weist mehrere Noppenprägungen 25 auf. Auch die Noppenprägungen 25 sind derart angeordnet, dass zwei an zwei benach barten Faltenwänden 21 angeordnete Noppenprägungen 25 symmetrisch ausgeführt sind. Dadurch wird zwischen den Noppenprägungen 25 ein Bereich 27 definiert, in dem sich die zwei Faltenwände 21 nicht berühren. The embossed knobs 25 are bulges on the inflow side 8 of the fold wall 21 . Each of the fold walls 21 has a plurality of embossed knobs 25 . The embossed knobs 25 are also arranged in such a way that two embossed knobs 25 arranged on two adjacent fold walls 21 are symmetrical. As a result, a region 27 is defined between the embossed knobs 25 in which the two fold walls 21 do not touch.
An den Faltenspitzen 22 der Falten 20 sind ferner Pleat-Lock-Prägungen 28 vorgese hen. Dies sind Eindrückstellen, die dazu dienen, die Faltenspitzen 22 benachbarter Fal ten 20 auseinander zu halten. At the fold tips 22 of the folds 20, pleat-lock embossings 28 are also provided. These are indentation points that serve to keep the fold tips 22 of adjacent folds 20 apart.
Fig. 4 zeigt einen Schnitt entlang der Linie B-B aus Fig. 3. In Fig. 4 sind die Noppenprä gungen 25, S-Prägungen 24 und Pleat-Lock-Prägungen 28 erkennbar. Auch ist in Fig. 4 der Bereich 27, der von den gegenüberliegenden Noppenprägungen 25 zweier benach barten Faltenwände 21 definiert wird, gut erkennbar. Fig. 4 shows a section along the line B-B of Fig. 3. In Fig. 4 the knob embossings 25, S embossings 24 and pleat lock embossings 28 can be seen. Also in Fig. 4, the area 27, which is defined by the opposite embossed knobs 25 of two neigh disclosed fold walls 21, clearly visible.
Fig. 5 zeigt einen Schichtenaufbau des Filtermediums 6. Das Filtermedium 6 umfasst ein Zellulosesubstrat 29, das mit einem Phenolharz 30 imprägniert ist, und eine auf dem Zellulosesubstrat 29 angeordnete ePTFE-Lage 31. Fig. 5 shows a layered structure of the filter medium 6. The filter medium 6 comprises a cellulose substrate 29 which is impregnated with a phenolic resin 30 and an ePTFE layer 31 arranged on the cellulose substrate 29.
Das Zellulosesubstrat 29 sorgt für die mechanische Stabilität des Filtermediums 6. Das Zellulosesubstrat 29 ist auf der Abströmseite 9 des Filtermediums 6 angeordnet. The cellulose substrate 29 ensures the mechanical stability of the filter medium 6 . The cellulose substrate 29 is arranged on the outflow side 9 of the filter medium 6 .
Die ePTFE-Lage 31, die auch als Membran auf das Zellulosesubstrat 29 aufgetragen werden kann, ist auf der Anströmseite 8 des Filtermediums 6 angeordnet. Die ePTFE- Lage 31 dient als Oberfiltrationsschicht für das Filtermedium 6, wobei Staubpartikel an ihr angelagert werden. Die ePTFE-Lage 31 weist zudem eine geringere Haftkraft und daher eine reversible Partikelablagerung auf, so dass das Abreinigen des Filtermedi ums im Gegenstromprinzip vereinfacht wird. Die ePFTE-Lage 31 ist in dem vorliegen den Ausführungsbeispiel auf das Zellulosesubstrat 29 laminiert. The ePTFE layer 31, which can also be applied to the cellulose substrate 29 as a membrane, is arranged on the inflow side 8 of the filter medium 6. The ePTFE layer 31 serves as a top filtration layer for the filter medium 6, dust particles being deposited on it. The ePTFE layer 31 also has a lower adhesive force and therefore a reversible particle deposit, so that the cleaning of the filter medium is simplified using the countercurrent principle. In the present exemplary embodiment, the ePFTE layer 31 is laminated onto the cellulose substrate 29 .
Das Phenolharz 30, mit dem das Zellulosesubstrat 29 imprägniert ist, dient außerdem als Bindemittel zwischen dem Zellulosesubstrat 29 und der ePTFE-Lage 31. Das Phe nolharz 30 ist nach dessen Aushärtung nicht mehr durch Wärmeeinwirkung verformbar. Das Risiko eines Faltenkollaps wird sowohl im normalen Betrieb der Filteranordnung 1 als auch im Reinigungsbetrieb in Gegenstromprinzip verringert. Fig. 6 zeigt schematisch ein Herstellungsverfahren zum Herstellen des gefalteten Filter mediums 6. In einem Schritt S1 des Verfahrens wird ein Zellulosesubstrat 29 mit Phe nolharz 30 imprägniert. Das Phenolharz 30 besteht aus einer Mischung einer Grund komponente und eines Vernetzers, die in bestimmten, dem Fachmann bekannten Ge- Wichtungen zueinander stehen. The phenolic resin 30 with which the cellulose substrate 29 is impregnated also serves as a binding agent between the cellulose substrate 29 and the ePTFE layer 31. The phenolic resin 30 can no longer be deformed by the action of heat after it has hardened. The risk of a fold collapse is reduced both during normal operation of the filter arrangement 1 and during cleaning operation using the countercurrent principle. Fig. 6 shows schematically a manufacturing process for producing the pleated filter medium 6. In a step S1 of the process, a cellulose substrate 29 is impregnated with phenolic resin 30. The phenolic resin 30 consists of a mixture of a basic component and a crosslinking agent, which are weighted in relation to one another in certain ways that are known to those skilled in the art.
Nachdem das Zellulosesubstrat 29 mit Phenolharz 30 imprägniert wurde, wird die ePT- FE-Lage 31 auf dem Zellulosesubstrat 29 angeordnet (Schritt S2). Die ePTFE-Lage 31 kann durch verschiedenste Verfahren auf dem Zellulosesubstrat 29 angeordnet werden.After the cellulosic substrate 29 is impregnated with phenolic resin 30, the ePTFE sheet 31 is placed on the cellulosic substrate 29 (step S2). The ePTFE layer 31 can be placed on the cellulosic substrate 29 by a variety of methods.
Insbesondere kommt das Laminieren als Verfahren infrage. Beim Laminieren wird die ePTFE-Lage 31 auf das Zellulosesubstrat 29 aufgebracht und das Zellulosesubstrat 29 mit der darauf angebrachten ePTFE-Lage 31 wird dann mittels Rollen zusammenge presst. Die Rollen können vorgeheizt werden, um die Adhäsion der ePTFE-Lage 31 auf dem Zellulosesubstrat 29 zu verbessern. In diesem Fall spricht man vom Heißlaminie ren. Sind die Rollen nicht vorgeheizt, spricht man von Kaltlaminieren. Im Schritt S3 des Verfahrens wird das Zellulosesubstrat 29 mit der darauf angebrachten ePTFE-Lage 31 gefaltet. In particular, lamination comes into question as a method. During lamination, the ePTFE layer 31 is applied to the cellulose substrate 29 and the cellulose substrate 29 with the ePTFE layer 31 applied thereto is then pressed together by means of rollers. The rollers can be preheated to improve the adhesion of the ePTFE layer 31 to the cellulosic substrate 29. In this case one speaks of hot lamination. If the rolls are not preheated, one speaks of cold lamination. In step S3 of the method, the cellulosic substrate 29 with the ePTFE layer 31 attached thereto is folded.
Im Schritt S4 des Verfahrens können die Falten 20 mit Prägungen versehen werden. Hierbei handelt es sich um S- oder Noppenprägungen 24, 25, die in eine Faltenwand 21 eingeprägt werden, oder um Pleat-Lock-Prägungen 28, bei denen Faltenspitzen 22 ein- gedrückt werden. In step S4 of the method, the folds 20 can be embossed. These are S or nub embossings 24, 25, which are embossed into a fold wall 21, or pleat-lock embossing 28, in which fold tips 22 are pressed in.
Zum Schluss wird das Phenolharz 30 ausgehärtet (Schritt S5). Vorzugsweise wird Phe nolharz unter der Einwirkung von Wärme ausgehärtet. Durch die Aushärtung des Phe nolharzes 30 wird zum einen das Zellulosesubstrat 29, mithin das Filtermedium 6, stei fer. Zum anderen wird die ePTFE-Lage 31 mit dem Zellulosesubstrat 29 verbunden. Zur Herstellung eines ringförmig geschlossenen Filterelements kann das Filtermedium auf ein Stützrohr aufgebracht und mit Endscheiben versehen werden, wobei die Endfal ten zur Ausbildung des Hohlkörpers miteinander verbunden werden. BezugszeichenFinally, the phenolic resin 30 is cured (step S5). Preferably, phenolic resin is cured under the action of heat. The hardening of the Phe nolharzes 30 is on the one hand the cellulose substrate 29, and therefore the filter medium 6, stiff fer. On the other hand, the ePTFE layer 31 is connected to the cellulose substrate 29 . To produce a filter element that is closed in the form of a ring, the filter medium can be applied to a support tube and provided with end plates, with the end folds being connected to one another to form the hollow body. Reference sign
1 Filteranordnung 1 filter assembly
2 Gehäuse 2 housing
3 Filterelement 3 filter element
4 Fluideinlass 4 fluid inlet
5 Fluidauslass 5 fluid outlet
6 Filtermedium 6 filter medium
7 Stützrohr 7 support tube
8 Anströmseite 9 Abströmseite 8 upstream side 9 downstream side
10, 11 Mittel 12, 13 Rohre 14, 15 Ende 16, 17 entgegengesetztes Ende 18, 19 Gegendruckventile 20 Falte 21 Faltenwand 22 Faltenspitze 10, 11 middle 12, 13 tubes 14, 15 end 16, 17 opposite end 18, 19 back pressure valves 20 pleat 21 pleat wall 22 pleat tip
23 Faltengrund 23 pleat base
24 S-Prägungen 24 S embossings
25 Noppenprägungen 25 knob embossings
26, 27 Bereich 28 Pleat-Lock Prägung 26, 27 Area 28 Pleat-Lock embossing
29 Zellulosesubstrat 29 cellulose substrate
30 Phenolharz 30 phenolic resin
31 ePTFE-Lage L Luft L' gereinigte Luft 31 ePTFE layer L air L' cleaned air
RO Rohseite RO raw page
RL Reinseite RL clean side
S1 bis S5 Verfahrensschritte S1 to S5 method steps

Claims

Ansprüche Expectations
1. Gefaltetes Filtermedium (6) für ein Filterelement (3) mit einem mit Phenolharz (30) imprägnierten Zellulosesubstrat (29) und einer ePTFE-Lage (31), die auf dem Zellulo sesubstrat (29) angeordnet ist. 1. Pleated filter medium (6) for a filter element (3) with a phenolic resin (30) impregnated cellulose substrate (29) and an ePTFE layer (31) which is arranged on the cellulose substrate (29).
2. Gefaltetes Filtermedium nach Anspruch 1, wobei die ePTFE-Lage (31) auf das Zellu losesubstrat (29) laminiert ist. 2. Pleated filter medium according to claim 1, wherein the ePTFE layer (31) on the cellulose loose substrate (29) is laminated.
3. Gefaltetes Filtermedium nach Anspruch 1 oder 2, ferner aufweisend Falten (20), die jeweils zumindest eine Prägung (24, 25, 28) aufweisen. 3. Pleated filter media according to claim 1 or 2, further comprising pleats (20) each having at least one embossing (24, 25, 28).
4. Gefaltetes Filtermedium nach Anspruch 3, wobei die zumindest eine Prägung (24, 25, 28) dazu eingerichtet ist, die jeweilige Falte (20) zu versteifen, und/oder Prägungen (24, 25, 28) von zwei benachbarten Falten (20) derart angeordnet sind, dass ein Be reich (26, 27) zwischen den zwei Falten (20) definiert ist, in dem sich diese nicht berüh ren. 4. Pleated filter medium according to claim 3, wherein the at least one embossing (24, 25, 28) is designed to stiffen the respective fold (20) and/or embossings (24, 25, 28) of two adjacent folds (20 ) are arranged in such a way that a region (26, 27) is defined between the two folds (20) in which they do not touch.
5. Gefaltetes Filtermedium nach Anspruch 3 oder 4, wobei sich Prägungen (24, 25, 28) von zwei Falten (20) zumindest teilweise gegenüberliegen. 5. Pleated filter medium according to claim 3 or 4, wherein embossings (24, 25, 28) of two folds (20) are at least partially opposite.
6. Gefaltetes Filtermedium nach einem der Ansprüche 3 bis 5, wobei es sich bei den Prägungen (24, 25, 28) um Noppen- (25) und/oder S-Prägungen (24) und/oder Pleat- Lock-Prägungen (28) handelt. 6. Pleated filter medium according to one of claims 3 to 5, wherein the embossings (24, 25, 28) are nubs (25) and/or S-embossings (24) and/or pleat-lock embossings (28 ) acts.
7. Gefaltetes Filtermedium Anspruch 6, wobei zumindest eine Falte (20) zumindest zwei Pleat-Lock Prägungen (28) aufweist und wobei zwischen den zwei Pleat-Lock Prägun gen (28) zumindest eine S-Prägung (24) oder eine Noppenprägung (25) vorgesehen ist. 7. Pleated filter medium according to claim 6, wherein at least one fold (20) has at least two pleat lock embossings (28) and wherein between the two pleat lock embossings (28) there is at least one S embossing (24) or one nub embossing (25 ) is provided.
8. Gefaltetes Filtermedium nach einem der Ansprüche 3 bis 7, wobei jede Falte (20) identische Prägungen (24, 25, 28) aufweist. 8. Pleated filter medium according to any one of claims 3 to 7, wherein each pleat (20) has identical embossing (24, 25, 28).
9. Filterelement (3), insbesondere Luftfilterelement, mit einem gefalteten Filtermedium (6) nach einem der Ansprüche 1 bis 8. 9. Filter element (3), in particular air filter element, with a pleated filter medium (6) according to one of claims 1 to 8.
10. Filteranordnung (1) mit einem Gehäuse (2) und einem Filterelement (3) nach An spruch 9, welches in dem Gehäuse (2) aufgenommen ist, wobei das gefaltete Filterme dium (6) des Filterelements (3) im Gegenstromprinzip abreinigbar ist. 10. Filter assembly (1) with a housing (2) and a filter element (3) according to claim 9, which is accommodated in the housing (2), wherein the folded Filterme medium (6) of the filter element (3) can be cleaned in the countercurrent principle .
11. Fahrzeug mit einem Filterelement (3) nach Anspruch 9 oder mit einer Filteranord nung (1) nach Anspruch 10. 11. Vehicle with a filter element (3) according to claim 9 or with a filter arrangement (1) according to claim 10.
12. Verfahren zum Herstellen eines Filtermediums (6) mit folgenden Schritten: 12. Method for producing a filter medium (6) with the following steps:
Imprägnieren (S1) eines Zellulosesubstrats (29) mit einem Phenolharz (30); Aufbringen (S2) einer ePTFE-Lage (31) auf das Zellulosesubstrat (29); impregnating (S1) a cellulosic substrate (29) with a phenolic resin (30); applying (S2) an ePTFE layer (31) to the cellulose substrate (29);
Falten (S3) des Zellulosesubstrats (29) mit der ePTFE-Lage (31); Härten (S5) des Phenolharzes (30). folding (S3) the cellulosic substrate (29) with the ePTFE sheet (31); curing (S5) the phenolic resin (30).
13. Verfahren nach Anspruch 12, wobei zwischen den Schritten des Faltens (S3) des Zellulosesubstrats (29) und des Härtens (S5) des Phenolharzes (30) Prägungen (24, 25, 28) in Falten (20) des Zellulosesubstrats (29) eingeprägt werden (S4). 13. The method according to claim 12, wherein between the steps of folding (S3) the cellulosic substrate (29) and curing (S5) the phenolic resin (30) embossing (24, 25, 28) in folds (20) of the cellulosic substrate (29) are impressed (S4).
14. Verfahren nach Anspruch 12 oder 13, wobei das Aufbringen (S2) der ePTFE-Lage (31 ) auf dem Zellulosesubstrat (29) durch Laminieren erfolgt. 14. The method according to claim 12 or 13, wherein the application (S2) of the ePTFE layer (31) on the cellulose substrate (29) takes place by lamination.
EP22727279.6A 2021-06-10 2022-05-03 Folded filter medium Pending EP4351758A1 (en)

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DE102021115022.1A DE102021115022A1 (en) 2021-06-10 2021-06-10 Pleated filter medium
PCT/EP2022/061753 WO2022258261A1 (en) 2021-06-10 2022-05-03 Folded filter medium

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DE10150073A1 (en) * 2001-10-10 2003-04-24 Mann & Hummel Filter Multiple layer filter medium used in pleated filters for filtering air, oil, fuel and water comprises a layer of filter-active material made from cellulose fibers and provided with an impregnation covered with a laminated material
US7138057B2 (en) 2004-07-22 2006-11-21 Gore Enterprise Holdings, Inc. Filter media
US8257459B2 (en) 2007-02-28 2012-09-04 Hollingsworth & Vose Company Waved filter media and elements
US8147583B2 (en) 2007-06-08 2012-04-03 Gore Enterprise Holdings, Inc. Multiple layer filter media
US10343085B2 (en) * 2011-10-14 2019-07-09 W. L. Gore & Associates, Inc. Multilayer porous composite
AU2016308653B2 (en) * 2015-08-17 2022-03-17 Parker-Hannifin Corporation Filter media packs, methods of making and filter media presses
PL3793711T3 (en) * 2018-05-18 2023-05-15 Mann+Hummel Gmbh Filter element, and filter system comprising a filter element and a housing
JP2020148331A (en) * 2019-03-15 2020-09-17 アイシン化工株式会社 Vent valve

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