Method for producing a filter element provided with a sealing part

Abstract

A method for producing a filter element provided with a sealing part in which the sealing material is introduced into a casting chamber between two tundish parts when in the non-cured state, and a compensation space connected to the casting chamber for the expansion of the sealing material.

Claims

1. A method for the production of a filter element (5) provided with a sealing part (6), comprising the steps of: providing a shaped filter media shaped for forming the filter element (5) the shaped filter media having a flow face and an adjacent lateral side face connected as adjacent faces, wherein the flow face is an inflow face or an outflow face; providing a casting apparatus (1) having a plurality of tundish parts, including: a first tundish part (2) defining a first chamber wall of a casting chamber (7); and a second tundish part (3) defining a second chamber wall of a casting chamber (7); wherein the casting chamber (7) is arranged so that a sealing surface (11), an opposing sealing surface (12) and a further sealing surface are formed on opposite chamber walls of the sealing part (6); placing the shaped filter media in position in the first and second tundish parts such the filter media abuts against the first tundish part (2) and the second tundish part (3); wherein the shaped filter media is placed such that an edge portion of one or more faces of the adjacent faces forms at least one wall portion closing the casting chamber (7), such that the first tundish part (2), the second tundish part (3) together with the shaped filter media together at least partially define the casting chamber (7); casting the sealing part by steps of: introducing a sealing material (7) in a non-cured state into the casting chamber (7); and curing of the sealing material (7) in the casting chamber (7), forming the sealing surface (11) and the opposing sealing surface (12) of the sealing part (6); wherein the casting chamber (7) is arranged so that the sealing surface (11) and the opposing sealing surface (12) of the sealing part (6) are formed on opposite chamber walls of the casting chamber.

2. The method according to claim 1, wherein in casting step, the sealing material is a PUR foam (polyurethane).

3. The method according to claim 1, wherein the casting apparatus (1) forms a radially outer leg onto the sealing part (6), the radially outer leg projecting axially outwardly to an end face (9) which abuts at least one of the sealing surfaces of the sealing part (6).

4. The method according to claim 1, wherein a compensation space (8) is arranged as a closed space within at least one of the tundish parts (2, 3), the radially outer leg is arranged in the compensation space (8).

5. The method according to claim 4, wherein an amount of non-cured sealing material introduced into the casting chamber (7) is dimensioned such that in the cured state, the end face (9) of the sealing part (6) is situated at a distance from a bottom (10) of the compensation space (8).

6. The method according to claim 4, wherein the compensation space is formed (8) as an open space in communication with the casting chamber (7).

7. The method according to claim 1, wherein after curing step, the method further comprises providing at least one side of the sealing part (6) with a chamfer (18, 19).

8. The method according to claim 1, wherein an axial direction, as defined herein, is a direction normal to a plane defined by the flow face; wherein a projecting tip of the first tundish part (2) projects axially into the casting chamber (7) between the adjacent lateral side of the filter element (5) and a radially outer leg of the sealing part, defining a recess (11) forming the sealing surface (11); wherein the second tundish part (3) in the casting chamber (7) has a second recess defining the opposing sealing surface (12) of the sealing part arranged opposite the recess (11); wherein the projecting tip of the first tundish part projects in an axial direction towards the recess of the second tundish part.

9. The method according to claim 1, wherein the recess of the second tundish part is aligned axially with the projecting tip of the first tundish part.

10. A filter element (5) produced by a method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and advantageous embodiments are described in the further claims, the description of the figures and the drawings. The following is shown:

(2) FIG. 1 a perspective view of two tundish parts defining a casting chamber for producing a sealing part to a filter element,

(3) FIG. 2 a section through a filter unit with a filter insert having a filter element and a sealing part molded onto the edge portion of the filter element

(4) FIG. 3 in one embodiment, two tundish parts for producing a sealing part to a filter element,

(5) FIG. 4 the filter element according to FIG. 3 in the installed state,

(6) FIG. 5 a sealing element presented alone,

(7) FIG. 6 a further sealing element.

(8) In the figures, identical are provided with the same reference numerals.

DETAILED DESCRIPTION

(9) FIG. 1 shows a casting apparatus 1 with a first tundish part 2 and a second tundish part 3, which serves to produce a filter insert part 4 comprising a filter element 5 and a sealing part 6. Using the casting apparatus 1 with the tundish parts 2, 3, the sealing part 6 can be produced and connected to the edge portion of a surface of the filter element 5 by casting or injection molding. Filter element 5 is, for example, an air filter element which consists for example of a folded filter paper and is in a rectangular shape, wherein the edge portion of the filter element 5 is provided with the surrounding sealing part 6 at two filter element sides.

(10) The two tundish parts 2, 3 define a casting chamber 7, into which the sealing material is introduced in the non-cured state. This takes place advantageously in such a way that initially the two tundish parts 2, 3 are joined together, then the filter element 5 is placed in the intended position and, finally, the sealing material is introduced in the non-cured state into the casting chamber 7. But it is also possible to first introduce the sealing material into the casting chamber and subsequently place the filter element in its intended position in which the edge portion projects into the sealing material. After the curing of the sealing material, tundish parts 2, 3 can be removed, the sealing part 6 will retain its shape and is fixedly connected to the edge portion of the filter element 5.

(11) A compensation space 8 is introduced in tundish part 2, which is connected to the casting chamber 7 and is formed as a closed space with a U-shaped cross section. Upon being introduced, the sealing material extends well into the compensation space 8. The amount of the introduced sealing material is in this case dimensioned such that even after the curing, the end face 9 of the sealing material projecting into the compensation space 8 is situated at a distance to the bottom or the top 10 of the U-shaped closed compensation space 8. This distance constitutes a compensation margin and makes it possible to compensate for variations in the dimensioning of the sealing material quantity or other process parameters that are determinative for the volume in the cured state.

(12) The two side sealing surfaces 11 and 12 of the portion of the sealing part 6 projecting into the compensation space 8 are bounded by the opposing chamber walls of the compensation space 8. A sealing force may be exerted on the sealing surfaces 11 and 12 in the installed state of the filter insert part.

(13) The compensation space 8 and the portion of the sealing part 6 projecting into the compensation space 8 are situated at a distance from the side surface facing the filter element 5. Between the exterior side of the first tundish part 2 and the side surface of the filter element 5, there extends a further portion of the sealing part 6, which surrounds the edge portion of the filter element 5.

(14) The second tundish 3 defines a further sealing surface 13 to a portion of the sealing part 6. This further sealing surface 13 is situated at a distance from the first two sealing surfaces 11 and 12 which are parallel to one another and correspond to the chamber walls of the compensation space 8. FIG. 2 shows a filter unit 14 having a filter insert part 4 which is produced according to the embodiment of FIG. 1. The filter unit 14 comprises a filter housing 15, in which the filter insert part 4 can be inserted, wherein the sealing part 6 at the edge portion rests against the end face of the filter housing 15 and is contacted by a cover 16 which is attachable to the filter housing 15 by means of a not shown connecting element such as a screw. The contact direction of the sealing force for sealing by means of the sealing surfaces 11 and 12 extends transversely to the flow-through direction of the filter element 5. Thus, it constitutes at least substantially a radial seal. An additional (smaller) component of the sealing force is initiated by the sealing surface 13 parallel to the flow-through direction of the filter element 5.

(15) In FIGS. 3 and 4, a further embodiment is illustrated. FIG. 3 shows a casting apparatus 1 with two tundish parts 2 and 3, between which a casting chamber 7 is formed for producing a sealing part 6 to a filter element 5, wherein the filter element 5 and the sealing part 6 together form a filter insert part 4. The two tundish parts 2 and 3 of the casting apparatus 1 define a casting chamber 7 for receiving the sealing material 7, with an open compensation space 8 further provided between the two tundish parts 2 and 3, which is open to the exterior, i.e. to the surroundings. Upon introducing sealing material into the casting chamber 7, the sealing material expands into the compensation space 8, which is connected to the casting chamber 7. After curing, an end face 9 is formed at the open end side of the portion of the sealing part 6 projecting into the compensation space, but has no sealing function in the installed state of the filter insert part. The chamber walls of the casting chamber 7, which are respectively formed by side walls of the tundish parts 2 and 3, define the sealing surfaces 11 and 12 of the portion of the sealing part 6 formed in the casting chamber 7.

(16) FIG. 4 depicts a filter unit 14 with the installed filter insert part 4. The sealing portion 6 is defined by the mutually facing end faces of the filter housing 15 and the cover 16 and receives a sealing force. The contact direction of the sealing force for sealing by means of the sealing surfaces 11 and 12 extends in parallel to the flow-through direction of the filter element 5. Thus, it constitutes at least substantially an axial seal. The free end face 9 projects into a receiving space, however it does not fulfill a sealing function.

(17) As can be seen in FIGS. 5 and 6, different faces of the sealing part 6 may be provided with a chamfer 18 and 19 respectively. In particular, this facilitates insertion into the filter housing. There may be one or more of such chamfers 18, 19 provided, the angle of which is adapted to the respective installation situation. The chamfers 18, 19 are either already produced during the casting process by providing corresponding chamfers in the tundish parts, or the chamfers on the sealing part 6 can also be produced subsequently by mechanical processing.

(18) In the tree forms shown in FIGS. 5 and 6, the sealing surfaces 11 and 12 extend substantially parallel to the flow-through direction of the filter element 5. The contact direction of the sealing force thus extends transversely to the flow-through direction. These cases constitute radial seals.