DE102018221550A1 - Filter device - Google Patents

Abstract

Filter device (1) for filtering a fluid (3), in particular for separating solid contaminants from a liquid or from a gas, with at least one filter space (5), the at least one filter space (5) being at least partially by one for the fluid ( 3) is surrounded by permeable filter element (7), and with at least one suction point (13) for connecting a conveying device (152), in particular an electrically operable conveying pump for the fluid (3), in particular via one end to the suction point (13) and the other suction line (15) which can be connected to the conveying device, the filter element (7) having at least one filter disk (17), characterized in that the filter disk (17) is shaped and arranged such that gas bubbles (30) appearing in the conveying operation of the conveying device in the filter space (5) climb along the filter element (7) on a strictly monotonously upward path (32) to the suction point and at the suction can be sucked off together with the fluid.

Description

State of the art

The invention relates to a filter device according to the type of the independent claim.

Due to legal requirements, the exhaust gas from motor vehicles must comply with certain limit values. To meet these limit values, exhaust gas aftertreatment systems are used downstream of the internal combustion engine, the aim of which is to reduce the particle and nitrogen oxide concentration in the exhaust gas. The filters and catalysts used for this require that certain oxidizing / reducing agents be introduced into the exhaust system. Such agents are typically hydrocarbons or urea-water solutions for the selective catalytic reduction of nitrogen oxides in an SCR catalytic converter. For this purpose, a urea-water solution used as a reducing agent is conveyed from a tank to a metering module with the aid of a delivery module, which dispenses the necessary flow of reducing agent into the exhaust line as a spray.

It is already from here, for example DE 10 2011 087 532 A1 known to provide a tank for such a reducing agent with a filter device.

Filter devices are designed to be scalable from the US 2009/0184064 A1 known.

In today's SCR systems, filters are installed in which paper, sieve cloth and / or multilayer materials are used as filter material. An increase in the dirt holding capacity for a given filter material is achieved by pleating the materials used. Pleated filter materials for fuel filters are already out of the DE 157 63 48 known. The use of pleated filter materials in filter devices for aqueous urea solutions is already in DE 10 2012 201 434 A1 and in DE 10 2013 217 333 A1 described. Concepts with pleated filter material have the disadvantage that the plastic injection molding tool used to incorporate the filter material into the filter arrangement has to be precisely matched to the number of pleated pleats, and thus the filter area cannot be varied as desired and can be tailored to the respective application at low cost.

Disclosure of the invention

The filter device according to the invention with the characterizing features of the independent claim has the advantage of filtering a fluid with only slight pressure fluctuations. Another advantage is that no pleated filter material is required and a scalable filter device can thus be provided in a simple manner. A modular filter unit can be provided, in which the filter area can be varied almost as desired, without different design variants, e.g. use in injection molds and have to test them under changing conditions with regard to loading behavior, durability, etc. This results in a short adjustment time and thus a cost saving. It is also advantageous that filter material can be processed, which can be extrusion-coated but not pleated.

The measures listed in the dependent claims allow advantageous developments and improvements of the filter device specified in the independent claim.

It is advantageously provided that the filter device has individual filter elements, each with at least one filter disk, the filter elements being constructed in a modular manner with one another, in particular directly connectable to one another, so that the filter device can be adapted to different applications almost as desired. A single injection mold for a predefined geometry of a filter element is therefore sufficient to provide different overall filter areas of the filter device required in each case.

Figure list

• 1 eine Filtereinrichtung,
• 2 ein Filterelement mit einer Filterscheibe,
• 3 eine weitere Filtereinrichtung,
• 4 eine Detailansicht eines Filterelements,
• 5 eine weitere Detailansicht eines Filterelements,
• 6 eine weitere Detailansicht eines Filterelements,
• 7 eine weitere Detailansicht eines Filterelements,
• 8 einen Vorratsbehälter für ein Fluid und
• 9 einen weiteren Vorratsbehälter für ein Fluid.

Embodiments of the invention are shown in the drawing and explained in more detail in the following description.
Show it

• 1 a filter device,
• 2nd a filter element with a filter disc,
• 3rd another filter device,
• 4th a detailed view of a filter element,
• 5 another detailed view of a filter element,
• 6 another detailed view of a filter element,
• 7 another detailed view of a filter element,
• 8th a reservoir for a fluid and
• 9 another reservoir for a fluid.

Embodiments of the invention

In 1 is a filter device which can be immersed in a storage container (not shown here) for storing a fluid 1 for filtering the fluid during suction from the tank in the form of a modular filter unit 2nd shown. It has several filter elements 7 each with a filter disc 17th which are each rotated by 180 degrees to the next filter element and connected to it. A pair of such filter elements rotated relative to one another by 180 degrees forms a filter space module 23 , which has an opening at the top and bottom. Such an opening either forms a connecting channel 9 to an adjacent filter room module, or it is with a shutter 11 closed, or it forms a suction point 13 . In the case of the provision of several directly connected filter space modules 23 , as in 1 is shown, the bottom opening with the closure 11 for example closed in the form of a lid and the top opening as a suction point 13 by attaching an intake pipe 15 educated. The remaining openings are connected to one another and thus form connecting channels 9 for coupling the individual filter room modules, which are shared via the intake line 15 can be subjected to a suction force of a connected conveyor. If, alternatively, only one filter space module is provided, the upper opening serves as a suction point and the lower opening is closed. Alternatively, but less preferably, a reverse procedure can also be provided both in the case of a filter device with only one filter space module and in the case of a filter device with several filter space modules, that is to say attaching the closure 11 at the top and a suction line at the bottom of the single filter space module or filter column 25th consisting of at least two filter room modules.

Through the closure 11 becomes the clean side of the filter device, i.e. the interior 21st the filter device, separated from the raw side of the filter device, and via the suction line 15 the filtered fluid or the cleaned liquid can be sucked off, for example, via a delivery device or pump (not shown in more detail).

There can be any number of filter elements 7 are connected to one another in order to increase the size of the total available filter area of the filter device or the filter column to the desired size.

The filter device therefore has a body 19th on whose interior 21st a filter room 5 forms. Fluid to be filtered can only be through the filter elements 7 or filter discs 17th and via the suction point 13 in the interior 21st penetrate or leave the interior. The suction point and the filter elements are part of the body 19th .

2nd shows an isolated filter element 7 , as in the filter device 1 is installed. A partial cross-sectional side view is shown in partial image a) b ) a top view. The filter element contains a filter disc as an essential, filter-effective component 17th made of filter-effective material, which on its inner edge in the area of the opening 13 , 9 , which depending on the installation location of the filter element in the filter device as a suction point 13 or as a connecting channel 9 serves, and on its outer edge by a border web 4th is mechanically stiffened. Across the filter disc 17th extend four struts 6 , which connect the two boundary webs to each other and contribute to the mechanical stability of the filter element. The struts can be mechanically firmly connected to the filter disc. Optionally, the filter disc can only rest on the struts or rest on the struts. Edge webs and struts are preferably designed as a plastic frame. The opening 13 , 9 is arranged centrally.

In 2nd is the filter element with a rotationally symmetrical, tapered filter disc 17th shown. The conicity serves on the one hand to create better ventilation behavior and on the other hand to create a space for the extracted liquid. A cone, as in particular in 1 and 2nd is the preferred solution from a manufacturing point of view, but generally it is about inclined surfaces that are flatter with larger radii and steeper with smaller radii. The concept would also work with convex / concave bulging / bulging as long as the gas bubbles contained in the fluid or arising in the fluid during a pumping operation or suction operation or filtering operation only go upward. The filter disk is preferably not pleated in order to ensure easy scalability of the filter device. The connection of the filter elements, the cover and the suction line can be done, for example, by welding, locking, gluing and / or screwing. The design of the filter elements or filter discs can be designed flexibly depending on the available space. In addition to a round design, as in 2nd described, a polygonal or free-form configuration can also be provided. The material of the filter discs 17th can consist of sieve mesh, depth filtration material, cellulose, wire mesh, coated filter material or other substances suitable as filter material.

To be a very good one in the context of use with liquids at risk of freezing To ensure thawing behavior, the plastic frame of the filter element or the edges or the webs can be made of electrically conductive material, in particular of electrically conductive plastic. The mechanical reinforcement achieved by the edges or the webs can be produced by an encapsulation process, in particular by structured encapsulation with in particular electrically conductive plastic. In addition or as an alternative to this, the filter disk, that is to say the filter material itself, can also be made of electrically conductive material, so that an electrical heating current can flow directly through the filter material.

An alternative filter device is in 3rd shown. It is assumed here that the modular filter unit is installed vertically in a tank storing the liquid to be cleaned, and thus the lower area of the filter device is more heavily loaded with dirt. In this case, a larger area is required below over the service life to ensure an even pressure loss across the entire filter unit. In order to form this larger filter area in the lower area, larger filter space modules are made at the bottom 230 and smaller filter room modules at the top 23 used.

In 4th is a detail in cross-sectional side view of a filter element 7 with an opening 13 , 9 , especially here a suction point 13 , and a filter disc 17th made of filter material 170 shown. Also shown is fluid located in the interior of the filter device 3rd . The fluid located outside the filter device in the tank, not shown, is not shown for the sake of simplicity. Gas or air bubbles can occur during operation of the filter device, that is to say when the conveyor device is connected and in operation 30th arise in the interior of the filter device. The gas bubbles rise in the liquid and become from the filter disc or the filter material 170 to the suction point without sticking 13 forwarded. This is with a strictly monotonous upward path 32 the gas bubbles along the filter material, which has an angle of attack α to the horizontal of greater than or equal to 7 degrees.

In 5 is shown, as in the case of an angle of attack β of less than 7 ° the air bubbles no longer go directly to the suction point 13 are guided, but adhere to the filter material. As a result, they are accumulated until they reach a critical size and then reach the suction point as larger bubbles and lead to undesired pressure drops in the delivery line leading to the destination of the fluid.

In 6 a detailed view of another filter element is shown, in which different filter materials are used in different areas. In the example shown is in the two superimposed, also supported by a plastic frame, annular areas A and B Filter material with different mesh sizes and / or different coating provided. The air bubbles enlarge on their way up or form larger air bubbles so that their tendency to adhere to the filter material is reduced. So it is possible in the area B , so above, compared to below, the area A to provide a filter disc made of a coarser fabric, ie a fabric with a larger mesh size or larger pores. Alternatively or in combination, a suitably coated fabric can be used for the low and / or high filter disc of the filter element. Fiber composites made of paper and / or plastic or fabrics made of metal, glass fibers and / or plastic, for example polyamide, can be used as filter materials. By coating the fabric with polytetrafluoroethylene, for example, the wettability of the filter material is to be reduced to such an extent that the rising air bubbles do not stick to it and rapid "bubbling up" is ensured.

In 7 is a detailed view of another filter element is shown, in which different angles of attack in different areas γ and δ are provided. The low-lying area shows C. an angle of attack γ and the high-lying filter disk in the area D an angle of attack δ on, where γ larger than δ is. The two filter disks in C. and D consist of the same filter fabric. Alternatively, it is possible to add the mesh size analogous to the version in addition to the angle of attack variation 6 to vary.

The angle of attack is selected depending on the mesh size of the filter material and / or any internal support structure that may be present so that the desired bubble rise effect is reliably achieved. Example: With one and the same filter material, this can mean that a support fabric with a mesh size of 30 µm requires an angle of attack greater than 7 degrees, but a similar support fabric with a mesh size of 50 µm requires an angle of attack greater than 50 degrees.

8th shows a plan view of a storage container 154 for a fluid or a liquid, which by means of a conveyor 152 can be pumped out of the reservoir. For this purpose, the conveyor device has a plurality of filter columns which are laterally offset from one another 25th or filter room modules 23 via a common suction line 150 connected so that the fluid is sucked in through the filter columns or filter space modules and before being passed on to areas outside the Storage container can be filtered. Such an arrangement can be used in particular with large-area storage containers of low height in order to provide the largest possible filter area.

9 shows an arrangement similar to 8th in cross-sectional side view, with the individual filter room modules 23 laterally offset from each other and via the common suction line 150 with the conveyor 152 are connected. Like the conveyor device, the conveyor device in FIG 8th a pump outlet, not shown, which can be connected on the outer underside of the storage container to a pressure line for forwarding the fluid that is conveyed out.

As an alternative to the arrangements according to 8th or 9 can the suction line or the common suction line 150 also be connected to a conveyor module or a conveyor device which is arranged above the storage container or mounted on the tank top.

The use of aqueous urea solution as a fluid and the use of the invention in the context of a selective catalytic reduction of nitrogen oxides in exhaust gases from internal combustion engines is mentioned by way of example. Alternative applications are the injection of water and / or fuel into the combustion chamber and / or into the exhaust tract. The invention can also be used in filter cartridges detached from a tank arrangement. In general, the filter concept described can be used wherever liquids or gases are to be filtered. It is particularly advantageous in the case of liquid fluids that the filter elements or the filter disks are shaped or arranged in such a way that gas bubbles appearing in the conveying operation of the conveying device 30th in the filter room 5 along the filter elements 7 on a strictly monotonous upward path 32 can rise, in particular ascend to the suction point and can be suctioned off there.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102011087532 A1 [0003]
• US 2009/0184064 A1 [0004]
• DE 1576348 [0005]
• DE 102012201434 A1 [0005]
• DE 102013217333 A1 [0005]

Claims (26)

Filter device (1) for filtering a fluid (3), in particular for separating solid contaminants from a liquid or from a gas, with at least one filter space (5), the at least one filter space (5) at least partially from at least one for the fluid (3) permeable filter element (7) is surrounded, and with at least one suction point (13) for connecting a delivery device (152), in particular an electrically operated delivery pump for the fluid (3), in particular via one end with the suction point (13) and at the other, connectable to the conveyor suction line (15), the filter element (7) having at least one filter disc (17), characterized in that the filter disc (17) is shaped and arranged such that gas bubbles (30) appearing in the conveyor operation of the conveyor Ascend the filter chamber (5) along the filter element (7) in a strictly monotonous upward path (32) to the suction point and a can be sucked off together with the fluid at the suction point. Filter device (1) after Claim 1 , characterized in that the filter element is modularly connectable to at least one further filter element. Filter device (1) after Claim 2 , characterized in that the filter element is modularly connectable to at least two further filter elements. Filter device after Claim 2 or 3rd that the filter elements are constructed so that they can be connected directly to one another. Filter device (1) according to one of the preceding claims, characterized in that the filter space (5) is formed by the interior of a body (19), the fluid (3) only via the filter element (7) and via the suction point (13) can penetrate into the interior (21) or leave the interior (21) and the filter element (7) and the suction point (13) are components of the body (19). Filter device after Claim 5 , characterized in that the body (19) is shaped and arranged in such a way that the gas bubbles (30) can rise along all the surfaces of the body facing the interior (21) in a strictly monotonous upward path (32). Filter device (1) according to one of the preceding claims, characterized in that the suction point (13) is arranged geodetically at the top, in particular that the suction point is arranged at the geodetically highest point of the filter space (5). Filter device (1) according to one of the preceding claims, characterized in that the filter space (5) is surrounded on all sides by one or more filter elements (7). Filter device (1) after Claim 5 or 6 characterized in that the body (19) has at least one filter space module (23). Filter device (1) after Claim 9 , characterized in that the filter space module (23) has at least two filter elements (7) of essentially identical construction, which are arranged in mirror image to one another. Filter device (1) after Claim 10 , characterized in that one of the two identical filter elements (7) is arranged at the top and the other of the two identical filter elements (7) is arranged below, the filter elements each having an opening (13, 9), the opening of the upper filter element serving as a suction point (13) serves and the opening (9) of the lower filter element is closed in particular with a cover (11) or can optionally be connected to a further filter space module (23). Filter device (1) after Claim 9 , 10th or 11 , characterized in that the filter chamber (5) has at least two filter chamber modules (23) which can be arranged laterally offset from one another and can be connected to the conveying device (152) via a common suction line (150). Filter device (1) after Claim 9 , 10th or 11 characterized in that the filter space (5) has at least two filter space modules (23), the filter space modules forming a filter column (25) and the upper filter space module having the suction point (13). Filter device (1) after Claim 13 , characterized in that the filter space modules (23, 230) can accommodate fluid volumes of different sizes. Filter device (1) after Claim 14 , characterized in that the accommodatable fluid volumes decrease from bottom to top. Filter device (1) after Claim 13 , 14 or 15 , characterized in that at least two filter columns (25) are provided, which can be arranged laterally offset with respect to one another and can be connected to the conveying device (152) via a common suction line (150). Filter device (1) according to one of the preceding claims, characterized in that the at least one filter element or the at least one filter disk is conical or convex or concave in shape. Filter device (1) after Claim 17 , characterized in that in the case of a conical shape of the filter element (7) an angle of attack (a) of the conical shape to the horizontal is at least 7 degrees. Filter device (1) after Claim 18 , characterized in that the filter element (7) is shaped in a conical step with at least two different angles of attack (γ, δ). Filter device after Claim 19 , characterized in that both angles of attack (γ, δ) are each at least 7 degrees. Filter device (1) according to one of the preceding claims, that the areas of the at least one filter element (7) which are permeable to the fluid (3) have a height-dependent variation of the material from which these areas are made. Filter device (1) after Claim 21 , characterized in that the variation consists of a variation of a mesh size (A, B) and / or a chemical composition of a coating of the material (C, D) and / or a variation of the chemical composition of the material (C, D) itself. Filter device (1) according to one of the preceding claims, characterized in that the at least one filter element (7) is heatable. Filter device according to one of the preceding claims, characterized in that the at least one filter element (7) in addition to the at least one filter disk (17) has border webs (4), the border webs surrounding the filter disk at its edges, the border webs (4) optionally over at least one strut (6) is stabilized in position relative to one another. Method for producing a filter device according to one of the preceding claims, characterized in that the filter disc (17) is shaped and arranged in such a way that gas bubbles (30) appearing in the conveying operation of the conveying device in the filter space (5) along the filter element (7) at a strict level monotonically upward path (32) to the suction point and can be sucked off together with the fluid at the suction point. Container (154) for storing a fluid (3) with a filter device (1) according to one of the preceding claims, which is connected to a conveyor device (152) for pumping the fluid (3) out of the container via the filter device.

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