Filter part

Abstract

Filter part (19) with a filter wall (21) made of filter material, with an inner free space, wherein the inner free space (20) is in flow connection with an outlet opening and the medium to be filtered flows through the filter material into the free space (20) and finally through the outlet opening, wherein furthermore a ground plan area (13) of the filter part (19) is elongated and is formed with curved edges in the direction of extension, characterized in that the inner free space (20) is uniform, that the inner free space (20) is kidney-shaped, that the filter part (19) has a circumferential filter wall (21), that the circumferential filter wall (21) delimits the kidney-shaped free space (20), that the filter part (19) has an upper filter cover (26) and a base part (22), that the filter wall (21) is connected to the base part (22), that the filter cover (26) and the floor part (22) have matching elongated floor plans,wherein the upper filter cover (26) sits tightly and directly on the filter material, that the filter part (19) can be screw-fastened in a receiving housing with an outlet, that a central axis of the free space (20) is arranged offset with respect to the outlet and that for this purpose, ear-shaped protrusions (31) are formed on the filter cover (26), through which fastening screws (32) can protrude into threaded openings (33) of an air filter attachment housing (4) for fastening the filter part (12) in the air filter attachment housing (4) and that the outlet (10) has a collar (37) to which the base part (22) is plug-connected.

Description

The invention relates to a filter part according to the features of the preamble of claim 1.As prior art, reference is first made to WO 2009 / 106593 A1 for such a filter part. The filter part known from this publication is inserted into an air filter attachment and the air filter attachment is then closed with a cover which also engages over the filter part. The filter part itself is held in the air filter attachment only by the overlapping cover.JP H 04-109484 U discloses a liquid pump with a liquid filter. The liquid filter is arranged in a housing receptacle which is covered by means of a cover part with the filter element in between. The cover part is screwed to the housing receptacle.EP 1 096 133 A2 discloses a filter housing in a motor vehicle which is screw-connected to a battery box adjacent thereto. The filter element is accommodated in the filter housing, wherein a housing cover can be screw-connected to the filter housing. A comparable prior art is also given by DE 44 27 739 A1.Proceeding from the prior art initially described, the invention is concerned with the problem of specifying an advantageous filter part.This object is achieved in the subject matter of claim 1, wherein it is aimed at the inner free space being uniform, the inner free space being kidney-shaped, the filter part having a circumferential filter wall, the circumferential filter wall delimiting the kidney-shaped free space, the filter part having an upper filter ceiling and a base part, the filter wall being connected to the base part, the filter ceiling and the base part having matching elongate ground planes, the upper filter ceiling being seated tightly and directly on the filter material, the filter part being screw-fastenable in a receiving housing having an outlet, a central axis of the free space being arranged offset with respect to the outlet, and for this purpose projecting ear-shaped formations being formed on the filter ceiling.It is a filter part as can be used in an air filter attachment, more preferably according to one of the embodiments as described here. The filter part is formed differently from a usual round configuration. The filter part is elongated in plan view and is formed with curved marginal edges in the direction of extension. The filter material of the filter part can be provided pleated overall. This is preferably done with pleated folds which extend perpendicular to a flow direction and / or perpendicular to a ground plan extension direction of the air filter attachment. With regard to the filter material, other filter materials known for filter candles can also be used.The filter part can be screw-fastened in a receiving housing, i.e. for instance the air filter attachment. For this purpose, protruding formations are formed on the filter ceiling. These may be formed, for example, in the form of eyes which project beyond a plan view of the filter ceiling at a plurality of points, for example at three or four points, and through which screws can be inserted or screwed. The counter thread can also be provided in the receiving housing, i.e. for instance in the air filter attachment.In the direction of extension of the air filter attachment, in which a filter element is preferably to be inserted, the height of the filter element is preferably formed to be constant.One of the marginal edges of the filter element runs concave.The upper side of the filter part has a tightly sealed filter cover. The filter cover sits directly on the filter material. It can be glued or welded to it.The screw fastening of the filter part can be in a receiving housing of the air filter attachment, further preferably in one of the embodiments as described here. For this purpose, suitable formations are provided on the filter ceiling. These may be formed, for example, in the form of eyes which project beyond a plan view of the filter ceiling at a plurality of points, for example at three or four points, and through which screws can be inserted or screwed. The counter thread can also be provided in the receiving housing.The filter ceiling and the base part have an elongated plan view. This follows an inner opening cross section of the housing, i.e. in particular of the air filter attachment, into which the filter part is to be accommodated.The filter ceiling and the base part have matching ground planes.A turbomachine having an air filter attachment, as described, in particular designed as a side duct compressor with respect to the turbomachine, may be provided, wherein the air filter attachment has a housing and the filter part is arranged in a housing interior.The air filter attachment may have an inlet and outlet for air sucked through formed in the housing, the inlet and the outlet having a free opening cross section.In plan view, the housing of the turbomachine can be arranged at least partially within an outer contour of the side duct compressor, based on a projection of the compressor outer contours (blower outer contour) in the direction of an axis of rotation of the compressor blower, and can have a non-circular shape. Because the air filter attachment has a non-circular plan shape, at least with respect to a wall directly enclosing the filter part, it can be arranged extending in the circumferential direction of the compressor outer contour. It is thus preferably also elongated. Despite a considerable size, in particular in its direction of extension, it can be arranged at least partially within the outer contour of the compressor. This is preferably done with an inflow direction which is provided in the same direction as a direction of the axis of rotation of the compressor-blower.The air filter attachment can extend laterally to the opening cross section of the inlet or the outlet in a non-uniform manner with respect to the housing interior comprising the filter material and at least in one direction by an enlargement amount which corresponds to 11 / 2 times or more the dimension from a central axis of the respective opening cross section to a boundary of the opening cross section in this direction.There is thus an air filter with a flow path which, with respect to a vertical projection of the inlet at least, requires or at least makes possible an air flow differing from this projection. The enlargement given in any case in one direction can initially also mean an arrangement of filter material in a region which is not in the (initially) most advantageous pressure path between the inlet and outlet taken by the air sucked through. However, it has been recognized that this filter material also comes into effect, namely when the filter material becomes increasingly clogged on the direct path between inlet and outlet and the air searches for a longer path, but one which is associated with a (then) lower pressure loss.This is also advantageous if, at least as viewed from the inlet, there is a certain free space up to the beginning of the filter material in the flow direction, which free space extends as far as possible also over the entire filter surface, in particular extending in the direction of the enlargement dimension. Via this free space, the deflection of the flow can then increasingly take place freely.The design indicated enables the formation of air filters in combination with a turbomachine, such as in particular a side channel compressor, the housing of which is formed differently from the usual cylindrical shape and can adapt itself accordingly to the space conditions given.In particular, such a housing can be used, for example, in projection of an axis of rotation of the blower. Viewed from the side channel compressor, they have a circular-path-segment-shaped, kidney-shaped or oval outline. Here, inlet and outlet can be assigned to the ends of the circular path section, to the ends of the kidney shape or even to the ends of the oval.In particular, it is preferred that the free opening cross sections of the inlet and of the outlet coincide in a vertical projection or at least overlap and combined to form an optionally imaginary overall cross section, wherein furthermore the housing interior comprising the filter material extends laterally to the overall cross section at least in a direction by the named enlargement dimension which corresponds from a central axis of one of the opening cross sections, optionally of the opening cross section thus producing a part of the overall cross section, to the boundary of the overall cross section in this direction. In this respect, in the case of such an air filter, too, an asymmetrical housing configuration or, in any case, a housing configuration which is greatly enlarged compared to the aforementioned overall cross section results in relation to a direct flow path between inlet and outlet. This also leads to the fact that filter material which lies outside this total cross section is not, or is much less, flown through by the air flowing through. This situation can also be accepted here, since, in the course of a clogging of the filter material, a flow through the cross section of the filter material, which has initially been flowed through less, naturally also results, as it were, due to a pressure drop over the cross section which shifts therewith.Furthermore, with regard to the discussed designs of the air filter, the structural possibility arises of providing, in addition to the inlet and in a side-by-side arrangement thereto, a further structural element in the air filter, as is described in more detail further below. Moreover, even independently of the aforementioned possibility, such a design of an air filter attachment also opens up the possibility of achieving, with the same filter volume, i.e. the same amount of filter material through which flow can take place, an air filter which is at least of a smaller construction in one dimension and which can additionally be fitted favorably into an overall design of the turbomachine from the point of view of its external dimensions.The air filter attachment can be arranged within the outer contour of the turbomachine, in particular the outer contour of the housing of the compressor wheel, as viewed in a direction of the axis of rotation of the compressor wheel. However, it can also be arranged only partially within this outer contour. Furthermore, it can also be provided that the air filter attachment is arranged completely within the outer contour with respect to one end of an end region, but then grows beyond the outer contour in the circumferential direction.It is preferred that the said magnification measure, in particular starting from the inlet, is given only to one side. In particular, a cross-sectional area of the housing interior and / or of the housing exterior can also have an oval or circular ring-shaped configuration. Furthermore, a configuration of the cross-sectional surface or also of the housing as a whole, which configuration runs in a curved manner with respect to a geometric center axis of the cross section, is preferably also realized, in relation to a plan view.A further feature relates to the fact that, in a plan view of the air filter attachment, an opening or a connecting piece is provided in addition to the air inlet, said opening or connecting piece serving, for example, for holding or forming a safety valve. This connector is correspondingly overlapped or laterally offset with respect to the filter material, which is initially not flowed through or is flowed through much less. Should the air filter inlet become clogged in operation, the safety valve opens under corresponding negative pressure and can also immediately flow through the filter in a region which generally does not yet flow through substantially and is thus not yet substantially clogged.The inlet cross section of the inlet for air sucked through preferably corresponds to a usual standard cross section for an air filter attachment of a turbomachine for which the air filter attachment is provided, that is to say in particular a side duct compressor. It is correspondingly different with the compressor capacity of the turbomachine, if appropriate.With regard to the filter part, it is preferred that the elongated configuration of the plan view has a largest extent of extent which is greater than the height of the filter part. In particular in so-called candle filters, it is only known to form relatively high filter parts in which the dimension of the height by which the inner cavity extends starting from a base part in such a filter candle is greater than the greatest extension of the ground plan (in a plane or projected onto a plane).It is also preferred that the filter height is substantially constant in the direction of extension of the base surface, which is also preferably planar. A further preferred embodiment relates to the measure that at least one edge of the ground plan runs concave. Further preferably, the further edge is formed convexly with the same curvature.The invention is explained below in addition with reference to the attached drawing, which however merely represents exemplary embodiments of the invention. A part which is explained only with reference to one of the exemplary embodiments and in a further exemplary embodiment is not replaced by another part on account of the special feature pointed out there, is therefore also described for this further exemplary embodiment as a part which is in any case possible. The drawing shows: FIG. 1 shows a perspective illustration of a side duct compressor with an air filter attachment; FIG. 2 shows an illustration according to FIG. 1, but with an additionally mounted safety valve; FIG. 3 is a cross-section through the object according to the invention. FIG. 2 is a sectional view taken along the plane III--III in FIG. 2; FIG. 4 is a plan view of the filter housing according to FIG. 2 in isolation; FIG. 5 shows a schematic illustration of a side channel compressor, viewed in the direction of the axis of rotation of the blower and viewed on the rear side, with a filter in the form of a segment of a circular ring arranged in the outer contour of the blower; FIG. 6 shows a perspective view of a pleated filter part with a non-round plan view; FIG. 7 shows a top view of a blank of filter material, as can be used for producing the article according to FIG. 6, already partially pleated; FIG. 8 is a top view of the object according to FIG. 6 ; FIG. 9 shows a representation according to FIG. 6 of a filter part designed in the manner of a filter candle; FIG. 10 is a representation of the filter part according to the invention. FIG. 9 is a schematic view of the installation state; FIG. 11 is an exploded view of a further filter part with a further air filter attachment; FIG. 12 shows the air filter attachment according to. FIG. 11 is a plan view; FIG. 13 is a cross-section through the object according to the invention. FIG. 12 is a sectional view taken along the line XIII--XIII in FIG. 12; FIG. 14 is a bottom view of the article according to the invention. FIG. 12 :; FIG. 15 shows a further embodiment in a view according to. FIG. 12 :; FIG. 16 is a cross-sectional view of the object. FIG. 15 is a sectional view taken along line XVI-XVI in FIG. 15 ; and FIG. 17 shows a plan view of a further embodiment in a view according to. FIG. 12 is a schematic view of the present invention.Shown and described, first with reference to FIG. 1, is a side channel compressor 1 with a flanged electric motor 2 which has a blower 3. Furthermore, an air filter attachment 4 is attached to the side channel compressor and an air outlet attachment 5 formed with a sound protection device.FIG. 2 shows a comparable side channel compressor, wherein however a safety valve 6 is additionally flanged to the air filter attachment 4. This is an emergency valve which opens automatically should the air inlet be clogged once. The details are shown in FIG. 3. The air filter attachment 4 preferably has a connecting flange 11 for the possible attachment of the safety valve 6, see FIG. 1.The air filter attachment 4 is shown in plan view in FIG. 4. It can be seen that, based on the external view visible there, it has a non-round plan view 7. Overall, the design in this view is kidney-shaped.The housing interior is preferably designed to be the same as the outer contour, reduced by the respective wall thickness.In the housing interior, cf. FIG. 3, a filter material 8 is seated.On the air filter attachment 4, an outlet 10 is formed opposite an inlet 9. The free cross sections of the inlet 9 and outlet 10 are arranged slightly offset with respect to one another in a vertical projection. Taken together, they form the overall cross section G.Above the filter material 8, a free space is formed in association with the inlet, here specifically above the plane formed by the pleated edges of the filter material 8 and bounded by the associated inner surface of the housing, in which the air can initially escape freely if, due to a certain clogging of the filter material in the initially selected air path, the air flowing through searches for another path. This free space preferably extends above a projection surface of the entire filter material (projection in the inlet direction of the air or corresponding to a central axis of rotation of the blower).With reference to FIG. 4 and the inlet opening cross section visible there, a central axis M can be specified with respect to the opening cross section visible there. Starting from here, with regard to the total cross section G drawn in dash-dot line in FIG. 4, a dimension A in the first enlarging direction of the housing given here can be ablated from the central axis M up to the edge of the total cross section G.An overall dimension L of the housing interior space given in this enlargement direction corresponds in the exemplary embodiment to 2 to 3 times the dimension A, specifically approximately 2.5 times. A ratio of 1.5:5 is preferred.In the second magnification direction given here, corresponding ratios A' to L' result.The enlargement can also be provided only on one side.The ranges specified above and below also include all intermediate values with regard to the disclosure, in particular in that is to say, for example, a ratio of 1.6:5 or 1.5:4.9, etc., on the one hand for delimiting the stated range limits from below and / or above, alternatively or additionally but also with regard to the disclosure of one or more singular values from the respectively specified range.In the embodiment of FIG. 5, an air filter attachment 4 formed overall in the shape of a segment of a circular ring is provided. This is a schematic illustration. The inlet 9 and the (opposite) outlet 10 or inlet into the blower can be seen.Starting from the central axis M of the opening cross section visible there, a dimension A can be ablated from the central axis M up to the edge of this opening cross section. In view of the geometric layout in plan in the form of a circular ring section, dimension A is plotted on a center circle line K. Toward the outlet 10, the enlarging direction of the housing is given. An overall dimension L given in this enlargement direction, also in this respect ablated on the circular arc line K, corresponds in the exemplary embodiment to 5 to 10 times, specifically approximately 7 times, the dimension A. This range is also important for the exemplary embodiment described first.FIGS. 6 to 10 relate to filter parts as can be used in particular in a filter attachment according to the description above.Referring to Fig. 6, there is shown a filter member 12 which is made of pleated filter material 8 and has a plan surface 13 which is elongated, namely has a greater length l than width b. In this case, the width b is referred to the width of the filter part in a region over the longitudinal extent, not a possibly greatest width B, which is given without taking into account the curvature.In the direction of extension, as is the case in the embodiment in the direction of the length dimension l, the filter part clearly extends with curved marginal edges 14, 15, which in the embodiment merge into one another via more strongly curved end marginal edges 16, 17 (cf. also FIG. 8 ). The marginal edges with respect to the embodiment of FIGS. 6 and 7, i.e. of the filter part 12 formed continuously from pleated filter material, are here the marginal edges which result from the respective width extension of the filter material 8. They are in part correspondingly not coincident over their length with an actual real edge.The filter material 8 according to FIG. 7 is, for example, a nonwoven material which represents the initial state or is already pleated in this blank (left-hand region of the illustration) (right-hand region of the illustration). It is folded as a whole according to the illustration in FIG. 6, so that the final shape of the filter part according to FIG. 6 is then obtained. FIG. 8 shows the plan view of the filter part according to FIG. 6, but it can also be the plan view of the filter part according to FIGS. 9 and 10.Shown. FIG. 8 is a circular ring section with the rounded end faces mentioned. Here, a preferably geometrically uniform part is shown, which correspondingly also has a centre circle line K, as already explained with reference to FIG. 5.A curvature dimension E of a concave marginal edge 14 is preferred with respect to a given tangent T to the regions of this marginal edge 14 projecting furthest inwards in this respect and corresponds to one twentieth or more of a length l' between the points of contact of the tangent T with the marginal edge 14. In the case of a convex marginal edge, as given here with respect to the marginal edge 15, a tangent T' to the marginal edge 15 is to be taken as a starting point, parallel to the tangent T. In the point of contact of the tangent T' with the marginal edge 15, the dimension E' can be taken up to the centre circle line K, which dimension similarly preferably corresponds to one twentieth or more of the length l'. In both cases up to about half the length l'.With regard to the filter part 19 according to FIGS. 9 and 10, it is important that, beyond the aforementioned elongated configuration with curved marginal edges, it has a circumferential filter wall 21 delimiting an inner free space 20 and a continuous base part 22, Offset from a (surface) center point of the plan view of this filter part 21, air flows in, corresponding approximately to the arrow P in FIG. 9, wherein reference can also be made here to the real conditions as described in a filter header of the above description for the air inlet, it follows that this must emerge through the wall 21 in order to pass into the air outlet with the flow around the base part 22. For this purpose, the base part 21 can be placed on top of, for example. In the installed state, step sections 23 are seated, which allow a corresponding flow around.In the case of a filter part 19 as well, it can be seen that if the initially shortest region of the wall regions W shown shaded for the air flow is added with respect to, for example, the wall regions W shown shaded in FIG. 9, adjoining wall regions are sought for the passage of the air flow. In this way, too, continuous clogging of the wall can subsequently be achieved with a correspondingly offset inlet and outlet flow.FIG. 11 shows a further air filter attachment 4 which, as can be seen, has a plan shape in the form of a segment of a circle, with rounded narrow sides. The plan view shape refers to an extension of the air filter attachment in the assembled state in the circumferential direction of an impeller of the compressor.This air filter attachment 4 has an inlet 9 on the top side and an insertion opening 24 on the other side. The insertion opening 24 serves for inserting the filter part 12.On the underside, cf. also FIGS. 13 and 14, the air filter attachment 4 has an outlet 10, and preferably inlet openings 25 relating to a safety valve 6. The safety valve 6 is integrated in its entirety into the air filter attachment. It projects into the interior of the air filter attachment 4.The filter part 12 of this embodiment has a filter cover 26 and a base part 22, two separate filter walls 27 which are formed from pleated material as can be seen in the exemplary embodiment extend between the base part 22 and the filter cover 26. The pleated edges extend here, more clearly, preferably in the perpendicular, i.e. extending perpendicularly to the filter ceiling 26 or the base part 22, and thus also extend perpendicularly to a ground plan surface of the filter part or of the air filter attachment 4.The filter walls 27, as can be seen further from FIG. 12 for example, each delimit its own separate ground plan surface 28. These are each surrounded fully circumferentially by filter material 27. Such a separate ground plan surface 28 is preferably clearly circular or substantially circular (in relation to the pleated profile of the filter material in the exemplary embodiment).However, the filter part 12 overall has an elongated, circularly curved outline, as already mentioned, adapted to a cross-sectional contour of the interior 29 of the air filter attachment 4.Medium to be filtered, i.e. in particular air, flows through the inlet 9 into the air filter attachment 4 and then through the outlet 10 into the turbomachine. After the inlet 9, the medium to be filtered flows through one or both of the filter walls 27 into the inner free space 30, cf. also FIG. 13, which is surrounded by such a wall. As can then also be seen in particular further from FIG. 30, the medium to be filtered then flows from one or both free spaces 30 in each case through the same outlet 10, that is to say optionally into the connected turbomachine.If one of the filter walls 27 clog excessively, correspondingly more medium to be filtered can flow through the other filter wall 27. An advantageous compensation possibility is provided.The filter cover 26 further comprises ear-like formations 31 through which fastening screws 32 can project into threaded openings 33 of the air filter attachment housing for fastening the filter part 12 in the air filter attachment 4.In further detail, the base part 22 of the filter part 12 has an associated base opening 34 for each free space 30, while a receiving formation 35 is formed in the air filter attachment, also on the base side, on which the base part 22 rests on the edge side in the installed state. It is sealed there. At the same time, a flow channel 36 is hereby formed in the air filter attachment below the base part 22 and in cooperation therewith, which channel guides the through-flowing air overall to the outlet 10, which is preferably arranged on one side in this respect.In the embodiment of FIG. 15, the filter part 12 consists of a uniform circumferential but non-circular filter wall 27, which filter wall 27 here has the same outline as the filter part 12. FIG. 11 overall, irrespective of the gaps provided by the two filter walls 27 there. Accordingly, in the cross-sectional illustration of FIG. 16, only a uniform inner free space 30 is also obtained. A flow channel 36 is not provided there, but rather only the outlet 10 is formed, which is also arranged offset with respect to a central axis of the free space 30 here. The outlet 10 has a collar 37, to which the base part 22 is stretch-connected.FIG. 17 shows an embodiment in which, in an analogous configuration to the embodiment of FIG. 11, three separate filter walls are formed, also here with a respective circular separate plan view. Otherwise, the same conditions are obtained as described with respect to the embodiment of FIG. 11.List of reference characters1 Side channel compressor 2 Electric motor 3 Blower 4 Air filter attachment 5 Air outlet 6 Safety valve 7 Ground plan 8 Filter material 9 Inlet 10 Outlet 11 Connection flange 12 Filter part 13 Ground plan surface 14 Marginal edge 15 Marginal edge 16 Marginal edge 17 Marginal edge 18 Marginal edge 19 Filter part 20 Free space 21 Filter wall 22 Base part 23 Step 24 Insertion opening 25 Through openings 26 Filter ceiling 27 Filter wall 28 Ground plan surface 29 Interior 30 Free space 31 Formation 32 Fastening screw 33 Threaded opening 34 Base opening 35 Receiving formation 36 Flow channel 37 Plug collar M Central axis Dimension G Overall cross section A L Overall dimension K Central circular line l Length b Width B Width V Offset dimension W Wall regions E Curvature dimension

Claims

Filter part (19) having a filter wall (21) consisting of filter material, having an inner free space, wherein the inner free space (20) is in flow connection with an outlet opening and the medium to be filtered flows through the filter material into the free space (20) and finally through the outlet opening, wherein furthermore a ground plan surface (13) of the filter part (19) is elongated and is formed with curved marginal edges in the direction of extent, characterized in that the inner free space (20) is uniform, in that the inner free space (20) is kidney-shaped, in that the filter part (19) has a circumferential filter wall (21), in that the circumferential filter wall (21) delimits the kidney-shaped free space (20), in that the filter part (19) has an upper-side filter ceiling (26) and a base part (22), in that the filter wall (21) is connected to the base part (22), the filter cover (26) and the base part (22) have matching elongate ground planes, wherein the upper filter cover (26) is seated tightly and directly on the filter material, that the filter part (19) can be screw-fastened in a receiving housing with an outlet, that a central axis of the free space (20) is arranged offset with respect to the outlet and that for this purpose, protruding ear-shaped formations (31) are formed on the filter cover (26), through which fastening screws (32) can protrude into threaded openings (33) of an air filter attachment housing (4), for fastening the filter part (12) in the air filter attachment housing (4) and that the outlet (10) has a collar (37), to which the base part (22) is plug-connected.Filter part (19) according to claim 1, characterised in that the filter wall (21) consists of a pleated material.

Images