Patent Document

BACKGROUND OF THE INVENTION 
     The invention relates to a filter, in particular an air filter, comprising a housing and a filter element with a filter medium which filter element is arranged in the housing. In the area of an end face the housing is provided with a releasable lid by means of which the housing can be opened or closed. 
     In U.S. Pat. No. 5,547,480 an air filter is disclosed that comprises a cylindrical housing in which a filter element is arranged. The cylindrical wall of the housing has an air intake socket that opens into an annular chamber surrounding the filter element. One end face of the housing is provided with an air outlet socket that is in communication with the interior that is formed within the filter element. At the other end face of the housing there is a removable lid that is securable by means of clamp-like brackets on the cylindrical housing part. By releasing the brackets and removing the lid, the filter element can be removed and replaced with a new filter element. The filter element is comprised of a drum-shaped filter medium provided at its end faces with terminal disks that rest fluid-tightly against end faces of the housing or the lid. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a filter of the aforementioned kind with which the change of the filter element can be performed in a simple and safe way. 
     In accordance with the present invention, this is achieved in that the releasable lid and the filter element together form a common (unitary) component and in that the lid is designed as a terminal disk of the filter element. 
     Because the releasable lid and the filter element form a common or unitary component and at the same time the releasable lid is designed as a terminal disk of the filter element, the filter element is removed when the lid is removed so that only a single handling step is required. When inserting a new filter element, the lid is already provided on the filter element so that when the filter element is completely inserted into the housing the housing is already fluid-tightly closed. This simplifies not only the assembly but also assembly errors are prevented. 
     According to an expedient embodiment of the invention the lid that provides the terminal disk of the filter element is glued to the end face of the filter medium. In this way, a fluid-tight connection of the filter medium and the lid is provided. Moreover, it is advantageous that the lid has an axial socket that is received in a tubular section of a housing part and is sealed relative to it. This not only provides a safe securing action but at the same time also a sealing action relative to the housing part. In this connection it is advantageous that as a seal two annular beads are provided on the outer wall of the socket so that no additional sealing elements are required. In order to provide a defined position of the lid in the axial direction it is proposed that the lid comprises a radially outwardly oriented circumferential collar that rests against an end face of the housing. 
     According to a further embodiment of the present invention, the filter element has a substantially cylindrical support grid on which the filter medium is concentrically arranged. The support grid has the advantage that the filter medium in the radial direction as well as in the axial direction retains its shape precisely. It is furthermore advantageous that the support grid is dosed at the end neighboring the lid and forms part of the lid. This is achieved in that the part of the lid forming the terminal disk is designed as an annular element with a central opening and the closed end of the support grid fills out this opening. In this way it is possible to push the filter medium onto the support grid before joining the annular element and the support grid, to then place the annular element onto the end of the support grid, and to then provide a fixed (non-detachable) connection between the lid and the filter element by applying a suitable connecting means. 
     According to a further embodiment of the invention, within the support grid a safety element is arranged that is secured in a seal-tight way on an outlet socket. In this way it is prevented that through the outlet socket dirt can penetrate into the closed system when the filter element is damaged or is being exchanged. The safety element is comprised preferably of a further support grid and a further filter medium covering it. For facilitating manipulation when removing a soiled filter element and inserting a new filter element it is proposed that the lid is provided on its outer side with an arrangement for improved force introduction with regard to releasing or attaching the component. 
     While an air inlet socket is arranged at the outer surface of the housing, the outlet socket is expediently provided on the end face of the end of the housing facing away from lid an outlet socket and is concentrically arranged relative to the longitudinal axis of the housing. This outlet socket has advantageously an axially inwardly oriented section provided with an outer thread. This has the advantage that the filter element can be screwed onto the outer thread of the outlet socket when on the end of the support grid that is facing away from the lid an inner threat is provided. In this way a safe securing action for the filter element in the housing is provided. 
     Expediently, the support grid has at the second end facing away from the lid a radial flange that serves as a terminal disk correlated with this second end of the filter medium. The end of the filter medium is preferably connected to this terminal disk in the same way as to the annular element at the other end, i.e., preferably by an adhesive. The housing comprises expediently two, preferably however three, housing parts that are connected with one another in the area of their respective radial dividing planes. In this connection, it is possible to connect the housing parts mechanically with one another, in particular by a snap-on, locking or screwing connection. Such connections are releasable so that also the housing parts, as needed, can be detached from one another. In case that the housing parts are to be connected permanently to one another, i.e., they are non-releasable or non-detachable, the housing parts are preferably connected by welding or gluing with one another. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is a perspective illustration of an air filter with closure lid. 
         FIG. 2  is a view of the longitudinal side of the air filter housing. 
         FIG. 3  is a longitudinal section of the air filter. 
         FIG. 4  is a detail view of a section of a safety element. 
         FIG. 5  is an illustration of the detail V of  FIG. 3 . 
         FIG. 6  shows the air filter housing according to  FIG. 2  with a filter insert located outside of the housing. 
         FIG. 7  is a perspective illustration of the air filter according to  FIG. 6 . 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  illustrates an air filter  1  that has a housing  5  comprised of three housing parts  2 ,  3 ,  4 . On the housing part  2  an air inlet socket  6  is formed through which the airstream to be purified enters the housing  5 . At the central housing part  3  a flange  7  is provided that serves for attaching the air filter  1 . The housing part  4  has at its outer wall surface a vacuum socket  8  through which dust particles can be removed. The end face of the housing part  4  is closed off by a lid  9  on which a grip element  10  is provided. The grip element  10  has a substantially star-shaped outer contour and is provided centrally with a hexagon socket  11  provided for receiving a matching tool. The grip element  10  is thus an arrangement that serves for improving force introduction for turning the lid  9  by hand or by a tool. 
       FIG. 2  shows a view of the longitudinal side of the air filter  1  wherein L indicates the longitudinal axis of the housing  5 . The housing  5  is comprised of the housing parts  2 ,  3 ,  4  with the air inlet socket  6 , the flange  7 , the vacuum socket  8  and the lid  9  with grip element  10 . Moreover, this illustration shows an outlet socket  12  that is arranged concentrically to the longitudinal axis L. 
       FIG. 3  shows a longitudinal section of the air filter  1  with the housing  5  comprised of the housing parts  2 ,  3 ,  4 . The housing parts  2 ,  3 ,  4  have at their contacting surfaces radial dividing planes T 1  and T 2 . Adjacent to these dividing planes T 1  and T 2  the housing parts  2 ,  3 ,  4  are provided with locking devices  13 ,  14  so that the housing parts  2 ,  3 , and  4  can be mounted in a simple way. Since the locking devices  13 ,  14  extend about the circumference of the housing  5  and have mutually overlapping sections  16 ,  17  and  18 ,  19 , this also provides fluid tightness of the housing  5 . 
     On the housing part  2  an end wall  20  is formed that extends radially to the outlet socket  12  that is provided on the inner side of the end wall  20  with a section  21  projecting into the housing  5  and having an outer thread  22 . Along the end wall  20  there is a radial channel  25  with a connecting opening  26  for connecting a pressure gauge (not illustrated). The housing part  4  has at its end face  23  an opening formed by an axial tubular section  24  that extends from the end face  23  coaxially to the longitudinal axis L into the housing  5 . 
     In the housing  5  there is a filter element  15  which is essentially comprised of a filter medium  27  arranged on the support grid  28 . The support grid  28  has at the end arranged within the tubular section  24  a closed end wall  29  that is positioned within an opening of an annular element  30  and that fills the annular element completely. The annular element  30  and the end wall  29  form together the lid  9  illustrated in  FIG. 1 . The annular element  30  also forms a terminal disk  30 ′ of the filter element  15  and is fixedly connected to the filter medium  27  by an adhesive layer  31  and is sealed relative to it and the support grid  28 . The annular element  30  has an axial section  32  that is secured in the tubular section  24  and is provided on its outer side with a circumferential collar  33  that rests against a surface  34  of the end face  23  of the housing  5 . 
     At the end of the filter element  15  that is facing away from the lid  9  a radial flange  35  is arranged on the support grid  28 which serves as a terminal disk  35 ′ that is connected with the filter medium  27  also by an adhesive layer  36 . The section of the support grid  28  neighboring the flange  35  is provided with an inner thread  37  so that the support grid  28  for securing the filter element  15  in the housing  5  can be screwed onto the thread  22 . In the illustrated end position the lid  9  closes off the end face  23  located at the other end of the housing  5 .  FIG. 3  shows also that a coaxial cylindrical wall  38  is present within the housing part  2  by means of which the air stream entering through the air inlet socket is deflected so that the filter medium  27  is loaded uniformly with air across the entire length of the annular chamber  39  that surrounds the filter medium  27 . Within the support grid  28  there is a safety element  43  with a further support grid  40  that is secured frictionally in the outlet socket  12 . 
     In  FIG. 4  a section of the safety element  43  is shown in detail. The support grid  40  is provided on its outer surface with a filter medium  46  that is comprised of a thin material. It extends almost across the entire length of the support grid  40 ; only the area for attachment in the outlet socket  12  is spared. An annular groove  45  with a seal ring  44  is provided at this location for sealing the outlet socket  12 . A thread  47  (only one turn is shown) is provided for attachment. The filter medium is glued on or welded on, for example, by ultrasound. 
       FIG. 5  shows the detail V of  FIG. 3  at a larger scale. This illustration shows that in the housing part  4  the tubular section  24  is formed in which the axial section  32  of the annular element  30  is provided that is a component of the lid  9 . The annular element  30  forms the terminal disk  30 ′ for the filter medium  27  that is connected to the terminal disk  30 ′ by an adhesive layer  31 . On the outer surface of the axial section  32  there are two annular beads  41 ,  42  that rest against the inner wall of the tubular section  24  and in this way provide two axial seals at an axial spacing relative to one another. At the end face of the housing part  4  a surface  34  is provided against which the collar  33  of the annular element  30  rests. 
       FIG. 6  shows to the left the housing  5  according to the illustration in Fig. wherein same parts are identified by same reference numerals as in the afore described Figures. To the right in  FIG. 5  the filter element  15  is illustrated in a position removed from the housing  5  or before being inserted into the housing  5 . The filter element  15  is provided at one end with the lid  9  on which the grip element  10  is arranged. On the lid  9  an axial section  32  is integrally formed and provided with the annular beads  41  and  42 . At the end of the filter element there is flange  35  that is connected to the filter medium  27 . The filter element  15  and the lid  9  together form a unit so that for removing the filter element  15  from the housing  5  or for inserting it into the housing it is only necessary to handle a single component. 
       FIG. 7  shows a perspective illustration of the housing  5  with removed filter element  15 . In the opening at the end face of the housing part  4  the forward end of the safety element  43  can be seen. When exchanging the filter element  15  the safety element  43  remains in its mounted position and covers thus the outlet socket on the housing part  2  in order to prevent penetration of dirt into the connected system. In the case of an installed but damaged filter element  15  the safety element  43  fulfills also such a function. 
     The specification incorporates by reference the entire disclosure of German priority document 20 2007 006 769.0 having a filing date of May 8, 2007. 
     While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

Technology Category: b