Abstract:
An inertial separator ( 10 ) for removing droplets from a gas stream. The inertial separator ( 10 ) has a housing ( 18 ) which is provided with an inlet ( 11 ) for untreated gas and an outlet ( 12 ) for treated gas. In the housing ( 18 ) are first and second separation lamellae ( 13 ), with at least two first separation lamellae ( 13 ) being linearly arranged next to one another and separated by an interval A. The separation lamellae ( 13 ) each have a concave side ( 14 ) and a convex side ( 15 ). The first separation lamellae ( 13 ) are arranged parallel to the second separation lamellae ( 13 ) with the concave sides ( 14 ) of the separation lamellae ( 13 ) facing one another. The lowest region of the concave side ( 14 ) of the first separation lamellae ( 13 ) is situated opposite the interval A between the second separation lamellae ( 13 ). Viewed in the direction of flow, a drainage slope ( 16 ) which extends obliquely to the separation lamellae ( 13 ) is arranged on the second separation lamellae ( 13 ). This drainage slope ( 16 ) projects under the first separation lamellae ( 13 ), thereby preventing unpurified gas from exiting through the outlet ( 12 ).

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to an inertial separator, and to an oil module, a cylinder head cover, and an intake module in which such an inertial separator is integrated.  
           [0002]    An inertial separator for mechanically separating liquids and/or solid particles from a gas stream is known from German Patent Application No. DE 200 04 131. This inertial separator comprises two sheet metal shells mutually connected to a hollow body. Profiles are arranged parallel to one another at regular intervals in the sheet metal shells. The profiles in the first sheet metal shell are opened in the direction of the gas flow, and the profiles in the second sheet metal shell are opened in the direction opposing the gas flow. The profiles are formed by the incorporation of slots in the sheet metal shells with subsequent bending of the slotted regions. The bent regions interlock with one another, thereby reversing the gas stream twice before it passes through the inertial separator. This double reversal of the gas stream causes droplets or solid particles entrained in the gas stream to be propelled by centrifugal force against the profile. A liquid film thus forms on the interior of the profile which slowly drains down into a collecting channel.  
           [0003]    Similar inertial separators are also known from Wimboeck, U.S. Pat. No. 5,342,422 (=EP 615 098).  
           [0004]    Bending of the slotted regions creates transition zones in which there is insufficient reversal of the gas stream between the profiles. In this design, impurities may be impelled through the inertial separator, thereby impairing its efficiency.  
         SUMMARY OF THE INVENTION  
         [0005]    It is an object of the invention to provide an improved inertial separator.  
           [0006]    Another object of the invention is to provide an inertial separator which reliably removes impurities from a gas stream.  
           [0007]    These and other objects are achieved in accordance with the present invention by providing an inertial separator for separating particles or droplets from a gas stream, the separator comprising a gas inlet, a gas outlet; a plurality of separation lamellae arranged between the inlet and the outlet, the separation lamellae each having an arcuately-shaped design with a concave side and a convex side; at least two first separation lamellae being linearly arranged next to one another separated by an interval A with their convex sides facing the inlet, and at least two second separation lamellae being arranged offset from the linearly arranged first separation lamellae with the concave sides of the second separation lamellae arranged opposite the concave sides of the first separation lamellae, and a drainage slope for the separated impurities provided on the separation lamellae.  
           [0008]    The inertial separator according to the invention is advantageously suited for removing impurities such as dust or liquid droplets from a gas stream. To this end, the inertial separator comprises a housing with an inlet through which the gas to be purified enters the inertial separator and an outlet through which the purified gas exits. The inlet may have various cross sections, such as circular or rectangular shapes, for example. The outlet likewise may also have any desired cross section. However, the cross sections of the inlet and of the outlet need not correspond to one another. For example, the inlet may be designed as a circular bore and the outlet as a rectangular aperture. In other variants, the inlet and outlet may correspond to one another in area as well as in cross-sectional shape.  
           [0009]    Arcuately-shaped separation lamellae are arranged in the housing between the inlet and the outlet. The separation lamellae have a concave side and a convex side as a result of their arcuately-shaped design. The separation lamellae may also have, for example, an undulating shape with a plurality of inflection points. The separation lamellae may be made of synthetic resin material, for example, to reduce the weight of the component, although of course other materials such as metals may be used to produce the separation lamellae. The choice of material for the separation lamellae depends on the required material properties or environmental conditions. Metallic materials are better suited for high temperatures, whereas synthetic resin materials may be preferred under low thermal loads for cost reasons.  
           [0010]    The inertial separator has at least two first separation lamellae which are linearly arranged next to one another and separated by an interval. This interval creates a gap between the first separation lamellae, which are situated with their convex sides facing the inlet. Second separation lamellae, likewise linearly arranged, are provided offset from the linearly arranged first separation lamellae. These second separation lamellae are arranged with their concave sides opposite the concave sides of the first separation lamellae.  
           [0011]    A drainage slope is provided on the separation lamellae on which the separated impurities can drain off. A separate drainage slope may be provided on each individual separation lamella. Alternatively, a single drainage slope may join all first separation lamellae or all second separation lamellae, or all first and second separation lamellae combined. The drainage slope preferably extends at an angle between 0° and 90° relative to the inlet. The separated impurities slide downward via the drainage slope, and thus can no longer be carried through the inertial separator. In addition, the drainage slope prevents a leakage air stream from flowing past the separation lamellae.  
           [0012]    Separated impurities such as oil may be conducted from the drainage slope back to the untreated oil side, thereby being returned to the oil circulation system. Other impurities such as dust, if not recirculated, are conveyed to a waste receptacle, for example, which is emptied as needed.  
           [0013]    To facilitate the sliding of impurities down the drainage slope, the drainage slope may be provided with a surface structure which agglomerates the impurities and thus accelerates their sliding motion. The surface structure may be provided with indentations or channels which are arranged, for example, parallel or at any desired angle to the direction of the incoming gas flow.  
           [0014]    The gas flowing through the inlet is deflected and guided by the convex sides of the separation lamellae into the gap between the first separation lamellae. The gas stream is “bundled” by the gap and impacts against the center of the concave side of the second separation lamellae. Impingement of the gas stream on the second separation lamellae causes the impurities to be propelled against the separation lamellae, where drop-like impurities adhere and flow off. Dust-like impurities likewise fall downward.  
           [0015]    The gas stream is divided by the concave side and its flow is reversed. The reversal of the gas stream occurs in the region of the greatest acceleration, with the impurities being pressed against the separation lamellae by centrifugal force. After this first reversal the gas stream is turned back to the first separation lamellae, where it impacts against the concave sides of the first row of separation lamellae. The remaining impurities in the gas stream are separated on these first separation lamellae. The gas stream is again reversed by the concave sides of the first separation lamellae, and thus “bundled,” the purified gas can then exit from the inertial separator through the outlet.  
           [0016]    Depending on the purity of gas required after the impurities are separated, a plurality of successive rows of separation lamellae may be provided. The purer that the gas exiting the outlet is required to be, the greater the number of successive rows of separation lamellae that are provided.  
           [0017]    Furthermore, the degree of purity of the gas may also be regulated by the size of the gap between the separation lamellae. The higher the required purity of the gas, the narrower the gap that is chosen. In this regard it is important that the pressure drop caused by the inertial separator increases as the gap size decreases. Therefore, the gap size should be chosen to be as large as possible in order to optimize the ratio of the separation rate to the pressure drop.  
           [0018]    The separation lamellae are designed with a wall thickness as small as possible which at the same time assures sufficient stability of the separation lamellae. To this end, the wall thickness of the separation lamellae may be 0.1 to 10 mm. The stability of the separation lamellae must be adjusted to the operating conditions or the loads, for example, the incoming gas flow rate, which act on the separation lamellae. The wall thickness of the separation lamellae depends on the material used. Smaller wall thicknesses may be used with higher-strength materials than with lesser-strength materials. The size and weight of the inertial separator may be reduced by use of correspondingly thin separation lamellae.  
           [0019]    In accordance with one advantageous embodiment of the invention, the drainage slope is provided on the second separation lamellae. The drainage slope may be designed, for example, as a single piece with the separation lamellae. Alternatively, the drainage slope may be designed as a separate component and be connected to the second row of separation lamellae. In such case, the drainage slope may be connected to the second separation lamellae in a detachable manner, such as with screws, or in an undetachable manner, such as with adhesive. As a result of this design, the separation lamellae have a shape that is simple and economical to produce.  
           [0020]    According to one embodiment of the invention, the drainage slope terminates at the first separation lamellae, with a small space existing between the drainage slope and the first separation lamellae through which the separated impurities can drain away. By providing the drainage slope underneath the first separation lamellae, the separated impurities from the first and second separation lamellae may be removed via the same drainage slope. Furthermore, this drainage slope prevents a portion of the gas stream from bypassing the separation lamellae and escaping unpurified through the outlet.  
           [0021]    It is advantageous to provide a drip spout on the drainage slope to allow better drainage of impurities into a collection chamber. This drip spout has a downwardly tapering design which facilitates detachment of individual drops at the lower end of the drip spout.  
           [0022]    In a further embodiment of the invention, the separation lamellae are arranged at an angle between 90° and 180° relative to the inlet. With this arrangement, the inflowing gas first impinges on the first separation lamellae and is caused to flow along the lamellae, thereby separating initial impurities. As a result of this arrangement, the gas stream is also “gently” reversed, thereby preventing extreme turbulence.  
           [0023]    It is advantageous to design the separation lamellae for optimum flow in their lateral end regions along the vertical edge which form the termination of the arcuate shape. This prevents the gas from separating from the separation lamellae, and minimizes the pressure drop caused by the separation lamellae. The flow-optimized edge or end regions may be designed as curves or points, for example. When the edge regions are designed as points, the wall thickness of the separation lamellae constantly tapers until no more material is present. Thus, there is no longer a surface at the edge regions to which the impurities may adhere.  
           [0024]    In particular designs of the invention, the separation lamellae are constructed as circular segments, especially corresponding to one-quarter to three-quarters of a circle. These circular segments are simple to produce, and also have a continuous arcuate shape without inflection points which reduces the pressure drop in the inertial separator. The first separation lamellae may be arranged at any desired distance from the second separation lamellae, with the first and second separation lamellae also partially overlapping or interlocking with one another. The closer the arrangement of the separation lamellae to one another, the higher the separation rate of impurities.  
           [0025]    In accordance with another embodiment of the invention, a closeable liquid drain is mounted in the housing underneath the separation lamellae. This liquid drain enables liquid separated from the gas stream to be returned to a liquid container or to be removed from the system for disposal.  
           [0026]    A valve may be disposed on this liquid drain which is capable of being opened as needed. The valve may be opened automatically by a control or regulator, or manually by service personnel. It is advantageous to situate the liquid drain at the lowest point in a collection chamber for separated impurities. Collection of the impurities via the liquid drain allows the collection chamber to be emptied in a most efficient manner. If only dry particles are separated from the gas stream, these can naturally be removed via the liquid drain, with the liquid drain then acting as a dust discharge.  
           [0027]    An oil module for an internal combustion engine has an untreated oil side with an untreated oil inlet and a treated oil side with a treated oil outlet. An oil filter element is arranged between the untreated oil inlet and the treated oil outlet which seals off the untreated oil side from the treated oil side and filters impurities from the oil. This oil module has an inlet aperture for crankcase gas, with the crankcase gas being conducted through an inertial separator as described above and de-oiled. The de-oiled gas exits the oil module through a gas outlet. The separated oil is conveyed to the untreated oil side and thus returned to the oil circulation system.  
           [0028]    A cylinder head cover for covering a cylinder head of an internal combustion engine has a gas inlet connection and a gas outlet connection. An inertial separator as described above is arranged between the gas inlet connection and the gas outlet connection. Arranging the inertial separator on the cylinder head cover allows installation spaces, which otherwise would remain unused for design reasons, to be used to separate impurities from a gas. Thus, contaminated gas streams present in a region near the engine may be purified over the shortest distance and returned to circulation. The purification of crankcase gas represents an advantageous use of the inertial separator integrated into the cylinder head cover.  
           [0029]    In a further embodiment, at least one cyclone separator is connected downstream of the inertial separator for further cleaning gas which has been pre-cleaned by the inertial separator. The combination of both separation devices facilitates the optimal removal of impurities from the gas.  
           [0030]    An intake module for an internal combustion engine has an air inlet and an air outlet, with the air inlet connected so as to communicate with the internal combustion engine. An inertial separator of the type described above is arranged between the air inlet and the internal combustion engine. Various components such as an air filter, an air flow sensor, flaps or valves may also be installed. The inertial separator purifies the air entering the intake module by removing impurities such as dust or water droplets. This inertial separator may be used instead of or in addition to an air filter. When the inertial separator is combined with an air filter, the air is crudely pre-cleaned by the inertial separator, resulting in only a slight pressure drop. In addition, the service life of the filter element is increased, since coarse dirt particles no longer clog the filter.  
           [0031]    These and other features of preferred embodiments of the invention, in addition to being set forth in the claims, are also disclosed in the specification and/or the drawings, and the individual features each may be implemented in embodiments of the invention either alone or in the form of subcombinations of two or more features and can be applied to other fields of use and may constitute advantageous, separately protectable constructions for which protection is also claimed. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0032]    The invention will be described in further detail hereinafter with reference to illustrative preferred embodiments shown in the accompanying drawing figures in which:  
         [0033]    [0033]FIG. 1 shows an inertial separator in a sectional view taken along line B-B of FIG. 2;  
         [0034]    [0034]FIG. 2 shows a second sectional view of the inertial separator of FIG. 1 taken along line A-A;  
         [0035]    [0035]FIG. 3 shows a sectional view of a second inertial separator embodiment according to the invention;  
         [0036]    [0036]FIG. 4 shows a sectional view of a third inertial separator embodiment according to the invention;  
         [0037]    [0037]FIG. 5 is a perspective view of a row of second separation lamellae with an integral drainage slope;  
         [0038]    [0038]FIG. 6 shows a schematic diagram of a flow stream in an inertial separator embodiment;  
         [0039]    [0039]FIG. 7 shows a schematic diagram of a flow stream in another inertial separator embodiment, and  
         [0040]    [0040]FIG. 8 shows a schematic diagram of a flow stream in yet another inertial separator embodiment. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0041]    [0041]FIG. 1 shows an inertial separator  10  in cross section along the sectional line B-B according to FIG. 2. Inertial separator  10  is provided with an inlet  11  and an outlet  12 . Outlet  12  is separated from inlet  11  by separation lamellae  13  which are arranged in two parallel rows. Separation lamellae  13  are arcuately-shaped (see FIG. 2), and thus each have a concave side  14  and a convex side  15 . The first row of separation lamellae  13  in the direction of flow are situated with their convex sides  15  facing inlet  11 . The separation lamellae  13  arranged the next row in the direction of flow are situated with their concave sides  14  facing toward inlet  11 . Thus, the concave sides  14  of the two parallel rows of separation lamellae  13  are disposed opposite one another.  
         [0042]    In order to effect multiple reversals of the gas flow, the rows of separation lamellae  13  are offset relative to one another by approximately one-half arc. The two rows of separation lamellae  13  are arranged at a distance E of approximately 2 mm from one another.  
         [0043]    In this illustrative embodiment, a drainage slope  16  is disposed on the second row of separation lamellae  13  in the direction of flow. This drainage slope  16  is constructed as one piece with the second row of separation lamellae  13 . In the illustrated embodiment, the drainage slope extends at an angle of approximately 30° relative to inlet  11 . This angle may be increased or decreased, depending on which substances are to be removed from the gas stream.  
         [0044]    An attachment surface  17  is provided to affix second separation lamellae  13  and drainage slope  16  to a housing  18  which forms inertial separator  10 . The component comprising second separation lamellae  13  and drainage slope  16  is made of synthetic resin material and may be produced, for example, by an injection molding process. Housing  18  is also made of synthetic resin material with inlet  11  and outlet  12  being integrated into the housing  18 . Of course, separation lamellae  13  and housing  18  may also be made of other materials such as, for example, metal or ceramic.  
         [0045]    First separation lamellae  13  are constructed in one piece with housing  18 . In order to affix second separation lamellae  13  in a defined position with respect to first separation lamellae  13 , housing  18  has an assembly member  19 . Fastening surface  17  is affixed to this assembly member  19  with adhesive. As an alternative to this undetachable fastening, the drainage slope may also be fastened to assembly  19  by means of detachable connections such as screws or snap connections.  
         [0046]    Housing  18  is sealingly closed with a cover plate  20 , so that the gas to be purified can only flow in through inlet  11  and out through outlet  12 . In cover plate  20 , which also may be made of synthetic resin material, there is a drain plug  21  which is screwed into a liquid drain  22 . This drain plug  21  may be removed as needed, thus allowing the separated impurities to be removed from inertial separator  10 .  
         [0047]    [0047]FIG. 2 shows a cross-sectional view of an inertial separator  10  along sectional line A-A according to FIG. 1. Parts which correspond to FIG. 1 are identified by the same reference numerals. The first row of separation lamellae  13  comprises three separation lamellae  13  arranged next to one another and separated from one another by intervals A. Each interval A is the same for first separation lamellae  13  as well as second separation lamellae  13 .  
         [0048]    The gas to be purified flows through inlet  11  into inertial separator  10 . The gas impinges on the row of first separation lamellae  13 , thereby being deflected in such a way that it has to flow through intervals A between the separation lamellae  13  of the first row. Because the separation lamellae  13  of the second row are arranged behind intervals A in the direction of flow, the gas cannot flow directly to outlet  12 .  
         [0049]    Second separation lamellae  13  are arranged in such a way that the lowest region of concave side  14  is situated directly behind interval A. The gas stream is deflected again by concave side  14  of second separation lamellae  13 , with a portion of the impurities impinging against separation lamellae  13  and no longer being entrained in the gas flow. These separated impurities slide or flow downward in the direction of drainage slope  16 .  
         [0050]    The gas stream which is reversed by concave side  14  of second separation lamellae  13  impacts against the concave side  14  of first separation lamellae  13 , where an additional portion of the impurities is separated from the gas stream. These impurities also slide or flow downward in the direction of drainage slope  16 . The gas stream is again reversed by concave side  14  of first separation lamellae  13 , whereby the gas stream is guided in the direction of outlet  12 , and the purified gas exits inertial separator  10 .  
         [0051]    [0051]FIG. 3 shows a variant of an inertial separator  10  in a cross-sectional view along sectional line B-B according to FIG. 2. Parts which correspond to FIG. 1 are identified by the same reference numerals. In this variant, which essentially corresponds to FIG. 1, the first row of separation lamellae  13  and the housing  18  are constructed as separate parts which are assembled together.  
         [0052]    Housing  18  has a receptacle  23  in which the first row of separation lamellae  13  are glued in place. First separation lamellae  13  may be attached to the housing individually, that is, with each separation lamella  13  connected alone, or by means of a bar (not shown), that is, with all the first separation lamellae  13  connected to the bar (not shown). In this embodiment, housing  18  may be made of a different material than that comprising separation lamellae  13 . Of course, second separation lamellae  13  as well may be connected to housing  18  in the same manner as for first separation lamellae  13 .  
         [0053]    In this illustrative embodiment, outlet  12  is disposed at a 30° angle relative to inlet  11 . An inlet connector  24  is mounted in inlet  11 , and an outlet connector  25  is mounted in outlet  12 . Both connectors  24 ,  25  may be attached to gas lines (not shown). In this illustrative embodiment, second separation lamellae  13  are attached to housing  18  by screws  26  which extend through fastening surface  17 .  
         [0054]    A drip spout  27  is arranged on drainage slope  16 , which is disposed parallel to outlet  12 , in this illustrative embodiment. This drip spout  27  terminates drainage slope  16  and tapers downward. By means of the tapered portion, the impurities separated from the gas stream are released more easily and drop onto cover plate  20 , which is provided with an indentation or depression  28 . Indentation  28  is designed in such a way that the impurities flow into liquid drain  22 . Drain plug  21  is screwed out as needed, thereby allowing the separated liquid to drain out.  
         [0055]    [0055]FIG. 4 shows a variant of an inertial separator  10  in a cross-sectional view. Parts which correspond to FIG. 3 are provided with identical reference numbers. In this variant, outlet  12  is disposed at a 30° angle to inlet  11 , analogous to FIG. 3. However, cover plate  20  has no indentation  28 .  
         [0056]    In this embodiment, separation lamellae  13  are disposed at an angle of 45° relative to inlet  11 . Drainage slope  16  extends at an angle of approximately 80° to inlet  11 . At its lower end, the drainage slope is provided with drop edge  27  which enables the separated liquid to drain off.  
         [0057]    The gas to be cleaned of impurities enters inertial separator  10  through inlet  11 . The gas impacts against obliquely disposed separation lamellae  13 , where initial impurities are separated. The gas then undergoes multiple deflections or reversals via separation lamellae  13 , thereby separating additional impurities. The resulting purified gas exits the inertial separator via outlet  12 . The separated impurities flow along separation lamellae  13  and drainage slope  16  in the direction of liquid drain  22 .  
         [0058]    Drain plug  21  is screwed into liquid drain  22 . Drain plug  21  is designed as a connector, which may be joined to a hose (not shown), thus allowing the separated liquid to be continuously discharged from the interior of inertial separator  10 .  
         [0059]    [0059]FIG. 5 shows a row of second separation lamellae  13  along with their drainage slope  16  according to FIG. 3, in a perspective view. Parts which correspond to FIG. 3 are provided with identical reference numbers. Separation lamellae  13  are constructed in one piece with drainage slope  16  and fastening surface  17 . Three fastening holes  29  are situated in fastening surface  17  through which screws  26  (see FIG. 3) may be inserted and screwed into housing  18  (see FIG. 3).  
         [0060]    [0060]FIG. 6 shows a schematic diagram of a flow stream through separation lamellae  13 . Parts which correspond to FIG. 2 are provided with identical reference numbers. In this embodiment, first and second separation lamellae  13  are designed as three-quarter circular arcs which partially overlap or interlock with one another. The distance E between the respective first and second separation lamellae  13  has a negative sign as the result of the interlocking of separation lamellae  13 . The absolute value of distance E, and thus the amount by which first and second separation lamellae  13  overlap, may be dimensioned depending on the impurities to be separated. Interval A between separation lamellae  13  of a row may likewise have a value from a few millimeters to several centimeters, and may be dimensioned depending on the impurities to be separated.  
         [0061]    The gas to be purified flows vertically along the path indicated by arrows to first separation lamellae  13 . The gas stream is deflected in an arc-shaped pattern by separation lamellae  13  and must flow through interval A between separation lamellae  13  arranged next to one another. The gas stream is accelerated as a result of the small cross-sectional area between first separation lamellae  13 , and impacts against the concave sides  14  of the second row of separation lamellae  13  at maximum velocity.  
         [0062]    The arcuate shape of second separation lamellae  13  causes the gas flow to reverse and impact against the concave sides  14  of first separation lamellae  13 . There, the gas stream is reversed again and is guided through interval A between the second lamellae to the outlet (not shown).  
         [0063]    [0063]FIG. 7 shows a schematic diagram of an alternative flow stream through separation lamellae  13 . Parts which correspond to FIG. 6 are identified by the same reference numerals. In this alternative, separation lamellae  13  are designed as one-quarter arcs. In addition, four parallel rows of separation lamellae  13  are provided which are configured as two successively arranged pairs of separation lamellae  13  according to FIG. 6.  
         [0064]    Viewed in the direction of flow, the lamellae are arranged so that first separation lamellae  13  are followed by second separation lamellae  13 . In the direction of flow, behind second separation lamellae  13 , third separation lamellae  13  are arranged, whose alignment corresponds to first separation lamellae  13 . Fourth separation lamellae  13  correspond to second separation lamellae  13 . The distance E between the first and second rows of separation lamellae  13  with respect to one another is 2 mm, thus causing a less severe reversal of the gas flow and resulting in a smaller pressure drop through separation lamellae  13 .  
         [0065]    [0065]FIG. 8 shows a schematic diagram of an alternative flow stream through separation lamellae  13 . Parts which correspond to FIG. 6 are identified by the same reference numerals. Separation lamellae  13  have a semicircular design in this alternative. The distance E between the respective rows of separation lamellae  13  is zero. Interval A between the separation lamellae  13  of each row is approximately 20 mm. For this interval A, inertial separator  10  (according to one of FIGS. 1 through 4) creates a lower pressure drop than that for interval A from FIG. 6.  
         [0066]    In the alternative described in FIG. 8, separation lamellae  13  are arranged in six parallel rows, with two successive rows always being disposed with their concave sides  14  opposite one another. The separation region is thus formed by three separation lamellae  13  arranged in pairs. This threefold separation region has a higher separation rate than a separation region formed by two separation lamellae  13 .  
         [0067]    The foregoing description and examples have been set forth merely to illustrate the invention and are not intended to be limiting. Since modifications of the described embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed broadly to include all variations falling within the scope of the appended claims and equivalents thereof.