Patent Publication Number: US-11642611-B2

Title: Filter element

Description:
REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 16/607,806, the entire subject matter of which is hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a replaceable filter element having two end caps between which a filter material extends, which is provided in particular for a filter device with a removable end piece and an enclosure. 
     BACKGROUND OF THE INVENTION 
     Filter elements for filter devices of this type are, as shown by way of example in DE 10 2007014813 A1, state of the art and are used in a variety of designs and embodiments for the filtration of process fluids, hydraulic fluids such as hydraulic oils, liquid fuels and lubricants, for the treatment of liquid media and the like. The reliability of such filter devices depends to a very large extent on the fact that, after replacement due to certain operating phases having elapsed, the installed or newly installed filter elements exactly fulfill the specifications, such as filter fineness, filter surface and other parameters. If the relevant filter device is equipped with an inappropriate filter element resulting in reduced or even no performance, which can result in malfunction or even damage, in particular in expensive technical equipment, it can cause significant economic losses. 
     SUMMARY OF THE INVENTION 
     In view of this, the invention addresses the problem of providing a filter element characterized by an improved functional reliability in a simple design. 
     According to the present invention, this problem is basically solved by a filter element having, as a significant feature of the invention, a positioning device arranged on one of the filter element end caps. In conjunction with at least one corresponding positioning element of this end cap, the filter element, at least viewed in its circumferential direction, is positioned within the enclosure. Because the positioning, and thus, the establishing of the functional position of the filter element, depends on the presence of the positioning element matching the positioning at one of the end caps, the positioning device forms a safeguard, which ensures that the filter device can only be operated in conjunction with a filter element that is specifically suited and intended for the particular application. 
     In advantageous exemplary embodiments, the filter housing for the filter element has at least one housing head, to which the enclosure is attached. The positioning device is arranged between one of the end caps and a housing cover of the housing head forming the end piece. 
     In exemplary embodiments in which the enclosure is attached to an annular body, mounted to a wall part of a tank storing fluid via a support ring, the positioning device can be arranged between one of the end caps and the tank cap forming the end piece. 
     In advantageous exemplary embodiments, the positioning device has a guide web, which engages with a guide channel arranged as a positioning element in one of the end caps and which is open towards the interior of the filter element. The tongue and groove engagement then formed between the positioning device and the end cap forms a type of key-lock system, which ensures that the filter element can only reach the functional position if the positioning device and the end cap geometrically match. 
     Advantageously, one of the end caps may have a guide ring on its inside, projecting on both sides beyond an abutment ring, to which one free, frontal end of the filter material is attached. The guide channel, the outer circumference of which is attached to the guide ring, preferably extends along the entire height of the outer circumference. 
     In particularly advantageous exemplary embodiments, the guide ring for the filter element has a boundary surface projecting inwardly, in the direction of the interior of the filter element. The boundary surface interacts with at least one stepped boundary shoulder at an insert ring of the positioning device. The insert ring engages, preferably flush, in the operating state with the guide ring from the side of the filter head. A predeterminable axial distance is between the boundary surface and the boundary shoulder. While a rotational position of the filter element is predetermined by the tongue and groove engagement of the guide web of the positioning device with the guide channel of the end cap, the axial alignment of the filter element is performed with limited play. For a filter element, the other end cap is attached to the enclosure, and there are no special requirements for length tolerance. 
     Advantageously, the arrangement can be made such that the guide web for the filter element at the insert ring protrudes outwardly in the direction of the guide channel from the insert ring and has an installation length that is shorter than the guide length provided for the guide web within the guide channel recessed in one of the end caps. 
     The positioning device for the filter element can form an annular body, which bears the insert ring at the foot end and a head ring at the head end. The head end is at least partially in abutment with abutment parts of the housing head or the tank cap. For a housing cover detachably mounted to the housing head, the abutment parts can advantageously be formed at the head end. 
     In particularly advantageous exemplary embodiments, the arrangement for the filter element is such that latching parts at the head ring of the annular body engage with the abutment parts of the housing head in a latching manner for the purpose of axially mounting the positioning device at the housing head. The assembly process can be performed easily and conveniently by closing the housing, while the positioning devices are latched to the abutment parts. 
     Advantageously, the arrangement for the filter element may be such that at least one fastening bolt is provided between the head ring and abutment parts at the housing cover or at the tank cap. When the positioning device is securely attached by the bolt, the assembly process is particularly safe and comfortable. 
     Preferably, a plurality of, preferably three, spacing webs extend between the insert ring and the head ring for the filter element. At least one spacing web bears the guide web projecting on the former&#39;s outside. 
     In particularly advantageous exemplary embodiments, one of the end caps, arranged concentrically to its guide ring, bears an outer ring for receiving a sealing ring. A further sealing ring is arranged between the head ring of the positioning device and the abutment parts of the housing cover. 
     Advantageously, the outer circumference of the filter element can be circular-cylindrical with the assigned one end cap. The inner circumference of the interior components, such as the filter material, can form a Reuleaux triangle. A filter material designed in that way can have a larger filter surface when installed in a given installation space than would be possible for a filter element having filter material with a circular cylindrical cross-sectional shape on its inner circumference. 
     In a filter material forming a hollow body, the arrangement is advantageously such that a connecting longitudinal seam of the preferably pleated filter material ends in a position aligned with the guide channel in one of the end caps. 
     The filter device for the filter element can, as usual, have a bypass device, which is provided at the other end cap of the filter element. The bypass device opens onto the unfiltered side in the interior of the filter element. 
     By forming a filtrate chamber, the filter element can be accommodated in the enclosure at a predeterminable radial distance, which can be perforated at least in an axial longitudinal area adjacent to the bypass device. As a result, the filter device is suitable for installation in an appropriate fluid reservoir tank. 
     The other end cap, provided with the bypass device, may be firmly connected to the enclosure forming an attachment point. One of the end caps is attached to the housing head to form a floating bearing acting axially. 
     With particular advantage, a tag can be arranged in the peripheral area of one of the end caps, which tag can be read by an RFID sensor located at a wall part encompassing the relevant end cap. As is known, tags are data storage devices containing passive transponders. That data can be read by a state-of-the-art RFID sensor using radio waves. In the arrangement provided for by the invention, where the tag is located at the peripheral area of an end cap and where the scanner is located at an encompassing wall part, the distance between the data storage device and the reader can be minimized, permitting secure data transmission even at low electrical power. Data specifying the filter element can be stored in the data storage device. For instance, the data may permit the identification of only the chip of the filter element, for instance, in terms of its filter material, the media to be filtered, the dimensions, the manufacturing date and the like. In addition, data may be stored to allow identification of the individual filter element, such as a unique and preferably continuous serial number. If and to the extent to which the data are already defined during the production of the filter element, these data can be stored in a non-rewritable and read-only memory area of the data storage device such that they cannot be modified and in particular cannot be manipulated. Alternately or additionally, data that are generated only after the production of the filter element can also be stored. 
     In exemplary embodiments, in which one of the end caps is located within the housing head of the device, the sensor is advantageously arranged at the end cap encompassed by the housing head, and the RFID sensor is arranged at the housing head. If the RFID sensor is connected to a higher-level machine control of a hydraulic system, it can only be put into operation once the assigned filter element has been identified. In this way, the hydraulic system cannot be started or operated if a plagiarized product of poor quality is used, which could damage the hydraulic system. 
     The filter element, in particular provided for a filter device according to the invention, has a filter material extending between two end caps, one of which has a guide channel. The channel opens towards the interior of the filter element. 
     Advantageous embodiments and further developments of the filter element are also disclosed. 
     Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the drawings, discloses preferred embodiments of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring to the drawings that form a part of this disclosure: 
         FIG.  1    is a perspective view in section of a filter device according to a first exemplary embodiment of the invention, not drawn to scale; 
         FIG.  2    is an exploded perspective view of the filter element and the positioning device of the first exemplary embodiment of the filter device; 
         FIG.  3    is a perspective view in section of the filter element and the positioning device of  FIG.  1    in engagement, taken along a central sectional plane; 
         FIG.  4    is an enlarged, partial perspective view in section of the head part of the first exemplary embodiment, wherein the functional position is shown, in a centrally extending, vertical sectional plane; 
         FIG.  5    is a perspective view in section of the filter element and the positioning device interacting therewith of  FIG.  1   , viewed from below, along a horizontal sectional plane; 
         FIG.  6    is an end view in section of the filter element of the device of  FIG.  1   ; 
         FIG.  7    is an enlarged perspective view in section of the head part of a filter device according to a second exemplary embodiment of the invention, wherein the functional position is shown, along a centrally extending, vertical sectional plane; 
       and 
         FIG.  8    is a perspective view in section of a filter device according to a third exemplary embodiment of the invention, along a vertical sectional plane. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the attached drawings, the invention is described by way of example for tank-installation filter devices. In a first exemplary embodiment, a housing head  1 , which in conjunction with an enclosure  3  forms the filter housing for receiving a filter element  5 , is attached to an upper opening  7  in a tank  9 , which is shown only schematically. The rest of the tank, holding a fluid supply, is not shown. As usual in the case of tank installation filter devices, the enclosure  3  is provided, at least in a lower length area  11 , which is below the normal liquid level in the tank, with a perforation through which filtrate emerges from the chamber  13  in the filtering process. Chamber  13  is located between the outside of the filter material  12  of the filter element  5  and the enclosure  3  and forms the clean side during the filtration process. The inflow of the unfiltered matter is routed from a fluid inlet  15  in the housing head  1  to the inner filter cavity  17 , which is encompassed by the filter material  12 . 
     As can be seen more clearly in  FIGS.  2  to  4   , a fluid-permeable support tube  19  is arranged as a sheath of the filter material  12  on the outside of the filter material  12 , when the fluid flows through the filter material  12  from the inside to the outside during the filtering process. 
     The enclosure  3 , as shown in  FIG.  1   , has a bottom part  21  at the lower end of the perforated part  11 . The bottom part has the shape of a shell that is open towards the bottom. In the bottom of the shell there is a centrally located opening  23 . The contact area for an end cap  25  located at the lower end of the filter material  12  of the filter element  5  forms the top of the bottom part  21 . At the outer circumference, the bottom part  21  is firmly connected to the lower end of the enclosure  3  via a flange  27 . 
     As best shown in  FIG.  3   , the lower end cap  25  has a centrally located inner passageway  29  leading to the inner chamber  17 , which is normally closed by a bypass valve  31 . The bypass valve  31  has a two-piece valve housing, having an upper housing part  33 , which extends in the form of a bell into the interior  17  and which has a central opening  35  at the upper end. While this bell forms a valve body  33 , which is clipped to the end cap  25 , a second valve body  37  is formed integrally with the end cap  25  and has a ring of spaces disposed between retaining webs  39  arranged at intervals, which retaining webs form the holder of a closing spring  41  of the bypass valve  31 . The closing spring pre-stresses a closing body  43  for sealing engagement with a seat surface  45  at the edge of the opening  35  of the valve body  33 , from which it can be lifted in a pressure-actuated manner. 
     The end cap  47  forming the apron for the upper end of the filter material  12  has an upwardly projecting outer ring  51  above its peripheral edge  49 , which forms the apron for the filter material  12  and the support tube  19  resting thereon. The outer ring  51  has a circumferential, recessed annular groove  53  as a receptacle for a sealing ring  55  ( FIG.  4   ). When the filter element  5  is inserted into the filter housing, cf.  FIGS.  1  and  4   , the sealing ring  55  forms the seal against the housing head  1 . The end cap  47  has a central passage encompassed by a guide ring  57 . An upper part  59  and a lower part  61  of the guide ring protrude on both sides of an abutment ring  63 . At the underside of abutment ring  63 , the facing frontal or axial end of the filter material  12  is attached. The guide ring  57  including its upper part  59  and its lower part  61  interacts with a positioning device  65  shown separately in  FIG.  2   . The guide ring  57 , at its upper part  59  of, as shown in  FIG.  2   , has a handle bar  67  pivotally mounted and has a radially outwardly facing bulge  69  ( FIGS.  2 ,  5  and  6   ), which encompasses an inner, axially extending guide channel  71 , for the interaction with the positioning device  65 . As illustrated in  FIG.  4   , the channel  71  encompassed by bulge  69  is at least partially surrounded by the pleated filter material  12 . 
     The positioning device  65  has the form of a one-piece plastic body having a foot part formed by an insert ring  73  and an upper head ring  75  extending in a parallel plane to the insert ring  73 . These rings are interconnected by three spacer webs  77  evenly distributed along the perimeter, the length of the spacer webs corresponds approximately to the diameter of the insert ring  73 . As an engagement part that is in engagement with the guide channel  71  at the end cap  47  in the operative position (see  FIGS.  3  and  4   ), the insert ring  73  of the positioning device  65 , has, similar to the top part  59  of the guide ring  57  of the end cap  47 , a bulge  79 . Bulge  79  projects radially and forms an axially extending guide web, which in the operating position is fittingly guided in the guide channel  71 . The axial length of the bulge  79  is smaller than the guide length available in the guide channel  71 . The filter element  5  is rotatably positioned due to the engagement of the bulge  79  with the guide channel  71  of the end cap  47 . 
     As can be seen most clearly from  FIG.  4   , the positioning device  65  is inserted between the housing head  1  and the end cap  47  of the filter element  5 . To that end, the head ring  75  abuts abutment parts, which are located at a housing cover  81  forming the end part of the housing head  1 . The housing cover  81  is detachably bolted to the remaining part of the housing head  1 . Engagement parts  83  projecting at the top of the head ring  75 , spaced apart from one another, engage with recesses in the housing cover  81  not shown, which leave a free radial play for the engagement parts  83 . Further abutment parts are located at a cone body  85 , which passes through the central opening  87  of the head ring  75 . To this end, tongue-shaped latching parts  88 , which originate from the edge of the opening  57  of the head ring  75 , come into latching engagement with a circumferential notch  89  at the cone body  85 . The head ring  75  is sealed against the cone body  85  using a sealing ring  90  seated at the inner circumference of the opening  87 . The frictional connection between the sealing ring  90  and the cone body  85  forms a further immobilization of the head ring  75 . 
     The bottom part of the lower end cap  25  forming an attachment point  21  at the enclosure  3 , supports, as mentioned above and shown in  FIG.  1   , the filter element  5  against axial downwards movements. At the upper end of the filter element  5 , a floating bearing permitting upward motion is formed at the end cap  47  via the sealing ring  55 . To limit this motion to a desired axial play, a radially projecting rib  91  is formed at the inside of the lower part  61  of the guide ring  57  of the end cap  47 . The upper side of rib  91  forms a boundary surface  92 . This surface  92  acts as an abutment surface in conjunction with a stepped boundary shoulder  93 , which is formed in lobe-shaped extension  94  extending over the rib  91 . Extension  94  extends away from the lower edge of the insert ring  73  downwards into the interior  17 . The clearance between the rib  91  and the shoulder  93  limits the possible axial play of the floating bearing at the end cap  47 , which can be used to compensate any length tolerances of the filter element  5 . 
     As is most clearly shown in  FIG.  6   , the outer periphery of the filter element  5  formed by the support tube  19  is circular, while the inner circumference of the inner components of the end cap  47 , i.e., the guide ring  57  at the underside  61  of which the rib  91  with the boundary surface  92  is located, has the non-circular shape of a Reuleaux triangle. 
     As shown in  FIGS.  5  and  6   , in this kind of shaping, the bulge  69  encompassing the guide channel  71  is oriented towards the assigned end of the connecting longitudinal seam  95 , which is used to interconnect the ends of the web of the pleated filter material  12 , for example a mesh pack. As shown in  FIG.  6   , the pleat height of the filter material web is reduced in the area of the longitudinal seam  95  formed by welding or gluing. Unlike the upper end cap  47 , all components of the lower end cap  25  have a circular cylindrical outer and inner circumference. 
       FIG.  7    shows the area of the housing head  1  of a second exemplary embodiment of the filter device according to the invention.  FIG.  7    shows housing cover  81  forming the end part in a position separate from the housing head  1 . Deviating from the first exemplary embodiment, the head ring  75  of the positioning device  65  is not only attached by the frictional connection at the sealing ring  90  and the engagement of the latching parts  88  with the notch  89  of the cone body  85 , but by at least one fastening bolt  74 . Bolt  74  passes through the head ring  75  from below and attaches the cone body  85  to the top of the head ring  75 , at which no protruding engaging parts  83  are provided, and thus, determines the rotational position of the positioning device  65 . 
     Another difference from the first exemplary embodiment is that a holder  78  for a tag  96  forming a passive transponder is integrally formed at the top end of the upper end cap  47  of the filter element  5 . The tag  96  in the form of a flat chip is arranged in the holder  78  at a small distance from the wall of the housing head  1  encompassing the end cap  47 , preferably exchangeably. In the wall, a sensor opening  80  is formed in such a position that an RFID sensor  97  bolted therein is aligned with the tag  96  when the filter element  5  is in the functional position predetermined by the positioning device  65 , in which position the sensor  97  can scan the data stored in the tag  96 . 
       FIG.  8    illustrates a third exemplary embodiment, in which, in the functional position of the filter element  5 , the upper end cap  47  is not sealed against a housing head  1  by the sealing ring  55  located at its outer ring  51 , but against the inside of an annular body  60 , which is part of the assigned tank  9 . In conjunction with a support ring  62 , the annular body  60  also forms the mount of the enclosure  3 . The support ring  62  in turn is held by a wall part  8 , which forms an intermediate wall at the upper area of the tank  9 , which separates an upper tank casing  64  from the main chamber of the tank  9  below, into which the enclosure  3  extends. The tank attachment  64  forms the inflow chamber  66  for the supply of the unfiltered material via the fluid inlet  15  located at the tank attachment  64 . In the absence of the housing head  1  having the housing cover  81 , in this exemplary embodiment, the end part, which constitutes the abutment parts for the positioning device  65 , is formed by a tank cap  82 , which can be detachably mounted to the top of the tank casing  64  as a closure part of the inflow chamber  66 . 
     While various embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the claims.