Patent Abstract:
A filter module includes an axially extending central channel, a first hollow adapter having an interior through which the central channel extends, a second hollow adapter having an interior through which the central extends, one or more filter cells positioned between the first and second adapters and around the central channel, and an enclosure. The enclosure has a first retainer ring mounted around the first adapter, a second retainer ring mounted around the second adapter, and an envelope which is sealed to the first and second retainer rings and extends around the one or more filter cells.

Full Description:
This application, which was published as United States Publication No. U.S. 2008/0190837 A1 is a continuation of U.S. patent application Ser. No. 10/469,852, which issued as U.S. Pat. No. 7,357,866 B2 and is the United States National Phase of International Application No. PCT/EP02/01892, which was filed on Feb. 22, 2002, and claimed priority of German Application No. 101 11 064.2, filed on Mar. 8, 2001, all of which are incorporated by reference. 

   DESCRIPTION 
   The invention concerns a module for filtering media. The invention also relates to a filter device with a filter housing in which the filter module or the filter modules is/are installed together with an installation set. 
   The term filter cells is understood to include all structural types of filter cells, wherein the porous, planar components that can support a flow of a medium are preferably filter layers made of known basic materials, i.e., essentially, cellulose and/or artificial fibers and also diatomite. 
   Filter devices essentially consist of a reusable filter housing and the associated attachments for filtrate and nonfiltrate material, as well as exchangeable filters, such as filter modules with filter cartridges or filter cells. For conventional filter devices, contact between nonfiltrate material/filtrate and housing is unavoidable, so that the filter housing must be cleaned after use, i.e., after the removal of the used filter. Here, cross contamination from charge to charge cannot be excluded. 
   Another disadvantage is that contact of the operating personnel with contaminated filter cartridges or filter modules, as well as housing parts, is unavoidable, which is extremely problematic, particularly for toxic or infectious contaminants of the used filter module or for dangerous gaseous materials in the nonfiltrate material chamber. 
   The parts of the filter housing in contact with the product must be resistant to the nonfiltrate material/filtrate, which in turn makes various housing variants necessary. It is associated with this disadvantage that the filter housing cannot be standardized and adaptation to the appropriate medium is required. 
   In special application cases, the filter modules must be flushed and sterilized before use. In addition, a drip-free removal of the filter module from the filter housing is just as unlikely as complete residual filtration, which represents a significant disadvantage, particularly for expensive media. 
   Attempts have already been made to solve these problems by enclosing the filter cartridges or filter modules, but not all of the problems could be solved. 
   For example, DE 35 20 139 C2 describes a filter device for gases or fluids with a filter cartridge, which is attached to an adapter with two openings for the filtrate and nonfiltrate material. A media-sealed sleeve in the form of a tube is attached to this adapter. This sleeve surrounds the filter cartridge and during filtration contacts the walls of the filter bowl. 
   However, when the filter is changed, fluid can flow from the space between the supply connection or the outlet connection and the downstream blocking element outwards and onto the cover. This makes additional cleaning work necessary. 
   A corresponding enclosure of several filter cartridges is explained in DE 38 07 828 C2. 
   In a refinement of the filter-cartridge enclosure, which is described in DE 38 08 602 C2, the housing and also the supply and discharge connections are modified to prevent these disadvantages. The greatest disadvantage of this device is that when a filtering bag is provided, adaptations to the housing and attachments must also always be provided, so that the so-called standard housing can no longer be used. Retrofitting filter cartridges with filter bags is thus not possible. In addition, increasing amounts of fluid are left behind in the intermediate space between the filtrate and nonfiltrate material. This remaining fluid must be discarded. Corrosive or toxic media hinder the disposal of filter cartridges. This also applies for filter devices based on filter modules with filter cells. 
   In WO 98/23356, a filter device with a filter module is described. It was considered a disadvantage for conventional filter devices that after the removal of used filter modules, the housing had to be cleaned in order to prevent contamination of subsequent fluids. In addition, residual fluid collects at the outlet of the housing, so that the housing must be opened or removed, which is time- and cost-intensive. Therefore, it was proposed to completely enclose the filter modules, wherein a two-part compression-proof and pressure-sealed enclosure housing is provided, which is removed and disposed of together with the filter module. This enclosure housing is installed freely and without an additional filter housing directly in the supply and discharge pipeline. Thus, the assembly and disassembly of this enclosure housing for the purposes of disposal and for exchanging filter modules with enclosure housings is complicated. Furthermore, residual fluid comes out of the opened connection of the enclosure housing and the supply and discharge pipelines, which is a big disadvantage for corrosive, expensive, and toxic media. This enclosure housing requires a relatively large amount of space, so that either an adaptation of the filter housing or a reduction of the filter modules must be performed. In addition, this pressure-sealed internal housing, which is used only one time, is complicated and expensive in terms of production. Another disadvantage of this so-called single-use housing is that these cannot be produced for filter modules with filter surfaces &gt;1 m 2 . 
   Therefore, it is the task of the invention to create an enclosed filter module, and also a filter device which do not have the disadvantages of known filter modules and filter devices. In particular, residual filtration should be possible at a lower cost for the production of filter modules. In addition, contamination of the housing should be essentially prevented and the invention should allow the use of standard modules and standard housings. 
   This task is accomplished with a module that is characterized in that the enclosure device includes a media-sealed envelope and two retaining rings, the envelope is attached in a media-sealed fashion to the retaining rings, and each retaining ring is arranged on one adapter. 
   The envelope forms a so-called soft enclosure, which surrounds the filter cell package and seals off the exterior in a media-sealed fashion. The provision of retaining rings enables a simple attachment of the envelope without the adapters having to be changed. Overall, the enclosure device requires no additional space, so that nothing has to be changed to the dimensions of the filter cells and the filter housing. Therefore, standard housings and standard modules can be used, which merely have to be provided with the envelope. 
   The envelope does protect the housing from contamination, but when the filter module is removed, residue of the medium can still be discharged from the inlet or outlet opening. In order to enable drip-free removal, at least one retaining ring in the inlet or outlet opening may have at least one valve. 
   By means of the valve or valves in the retaining ring or rings, the inner space of the filter module, i.e., the space located between the filter cells and the envelope and forming the so-called nonfiltrate chamber or the filtrate chamber according to operation, can be filled and/or aerated with the medium, wherein the valves are designed such that they immediately switch to the closed position when the filter module is removed from the filter housing. This effectively prevents leakage of residue of the medium. The attachment of the valves in the retaining ring or rings enables simple production without damaging the envelope. 
   The envelope preferably consists of a flexible and/or elastic material. According to the purpose of use, corresponding materials are used which are resistant to toxic or corrosive media or are quite safe in terms of food. Preferably, a plastic material is used which belongs to the same class of plastics as the components of the filter module, i.e., the filter cells, spacing rings, etc., so that no material separation has to be performed for the disposal of used filter modules. 
   To produce the enclosure, preferably a tube film is used, which is pulled over the filter module perpendicular to the longitudinal axis, wherein the retaining rings are already arranged in the correct position at the tube film. Then the open ends of the tube are sealed, preferably fused, in a media-tight fashion. 
   Conventional filter modules have at the upper end a bowl-shaped adapter and at the lower end a plug adapter, which carries on its outer surface at least one sealing ring, particularly an O-ring. Filter modules with such adapters can be used, wherein according to the configuration of the adapter, the retaining rings have to be adapted. Thus, retrofitting of existing filter modules is possible. 
   If the enclosure has already been provided for the production of the filter module, it is advantageous if both adapters are the same, because then the same retaining rings can be used at both module ends. This reduces the production costs. 
   Preferably, plug adapters are used which carry on their outer side at least one sealing element, particularly a sealing ring, preferably an O-ring, because these known adapters already have attachment means for the retaining ring. The retaining rings are preferably set and attached to the adapter like a bayonet. 
   After filtration, residue of the medium can still be present in the filtrate or nonfiltrate channel, which can drip out when the filter module is removed. To prevent this, valves sealing these channels are arranged at least in the lower adapter and in the lower retaining ring. The valves are preferably configured as plate valves. 
   In order to be able to install the filter modules according to the invention in existing filter housings, an installation set is provided which has at least one annular base plate and one cover plate. The annular base plate is configured such that it fills up the space between the housing base and the filter module so much that the upper side of the base plate forms a contact surface for the envelope, wherein the base plate has a filtrate or nonfiltrate channel which connects the filtrate or nonfiltrate supply from the housing base to the opening at the lower retaining ring. Furthermore, the base plate has a means for receiving the lower adapter and the lower retaining ring of the filter module. The cover plate is configured so that it fills up the space between the housing cover wall and the filter module so much that the lower side of the cover plate forms a contact surface for the envelope. Furthermore, the cover plate has a means for receiving the upper adapter and the upper retaining ring. 
   The means for receiving the lower adapter includes a receiver bushing, which is designed such that the receiver provided originally as an adapter receiver fits in the base wall of the filter housing. 
   The cover plate is preferably formed in two parts and has an annular head plate and a distributor head inserted in the center in the head plate. 
   The distributor head can have several ventilation channels. Preferably, the distributor head has one ventilation channel for the filtrate channel and/or one ventilation channel for the nonfiltrate chamber, wherein this ventilation channel connects to the ventilation channel located in the upper retaining ring. The ventilation channel for the filtrate or nonfiltrate chamber is important during the first filling of the filtrate or nonfiltrate chamber. Furthermore, the distributor head can have a control channel, which connects to the space located between the envelope and the housing in order to be able to recognize a possible loss of the sealing function in the envelope at an early time. 
   If two or more filter modules are to be arranged one above the other in the filter housing, the filtrate or nonfiltrate chambers of the filter module must be connected to each other by the valves arranged in the retaining rings. Therefore, it is advantageous if an intermediate plate, which has an opening, is arranged between the filter modules. The intermediate plate is configured such that the space between the filter modules is filled up so much that the two end surfaces each form a contact surface for the envelope of the filter module. Furthermore, this intermediate plate has at least one connection channel, which connects the valve openings of the valves located in the retaining rings of the two filter modules to each other. 
   The filter device according to the invention has a filter housing in which at least one filter module according to the invention is arranged together with the installation set. The envelope of the filter module or modules is dimensioned such that during the filtration operation it contacts the housing wall of the filter housing and the adjacent components of the installation set. These adjacent components essentially include the base plate, the cover plate, and if necessary the intermediate plate. This guarantees that the envelope does not have to be compression-proof, because the pressure force is received and supported by the components of the installation set or the housing wall. 
   The control channel can also be used to simplify the filling or emptying of the filter module or modules. For this purpose, the filter device can have a pressure device connected to the control channel. After the completion of the filtration, the envelope can be compressed by applying an overpressure so that residual amounts are pressed out of the nonfiltrate chamber. During filling, a low pressure can be applied so that the envelope contacts the housing wall or the components of the installation set. 

   
     In the following, example embodiments are explained in more detail with reference to the figures. 
     Shown are: 
       FIG. 1 , a vertical partial section of a filter device according to a first embodiment, 
       FIG. 2 , an enlarged representation of the upper region of the filter device shown in  FIG. 1 , 
       FIG. 3 , an enlarged representation in the region of the receiver bushing of the filter device shown in  FIG. 1 , and 
       FIG. 4 , a partial section through a filter device according to another embodiment, which features several filter modules. 
   

   In  FIG. 1 , a filter device  1  is shown in vertical partial section. The filter device  1  has a filter housing  2 , which consists of a housing upper part  4  and a housing base  12 . The housing upper part  4  in turns consists of a housing cover wall  8 , at which a housing connection  6  is arranged in the center, i.e., in the region of the center axis of the filter housing, and a housing shell  10  extending downwards to the housing cover wall  8 . The housing upper part  4  is formed pressure-sealed and compression-proof and connected to the housing base  12  with a tensioning device that is not shown. 
   The housing base  12  has a filtrate connection  16  arranged in the center, i.e., in the center axis of the filter device, and an eccentric nonfiltrate supply  14 . For reverse operation, the nonfiltrate material is supplied through the connection  16 , thus the nonfiltrate connection  16 , and discharged through the “supply  14 ,” i.e., the outlet  14 . In the following, the module according to the invention is described in connection with the first method of operation. 
   In the filter housing  2 , a filter module is installed with the aid of an installation set, which consists of several components and is described later. The filter module, in the simplified representation shown here, has three filter cells  22 , with each filter cell consisting of two disk-shaped filter layers  23 , which are connected to each other at the outside periphery. All filter layers  23  have a central opening. These openings together form a filtrate channel  18 . Spacing rings  29  are located between the filter cells  22 . 
   At the upper and lower ends of the filtrate channel  18 , an upper adapter  24  and a lower adapter  26  attach to the filter cells  22 . The two adapters are identical in structure and each carry sealing rings  28  on their outer side. Up to the point that the two adapters are not identical, the construction of this example filter module is known from the state of the art, so that more a detailed explanation is not necessary. 
   At the upper and lower adapters  24 ,  26 , there are retaining rings  32 ,  34 , which can be set on the projections typically present on adapters of the bayonet seal type. On these retaining rings  32 ,  34 , a soft enclosure in the form of an envelope  30  is attached, which is fused to the retaining rings in the embodiment shown here (fuse seam  31 ). This envelope  30 , which can be, e.g., a film, surrounds the filter cells  22  and is dimensioned so that on one side it contacts the inner side of the housing shell  10  and on the other side it contacts the installation set components  60 ,  110 , and  120 , which will be described in detail in connection with  FIGS. 2 and 3 . Thus, a nonfiltrate chamber  19  is formed between the filter cells and the envelope  30 . 
   Both the upper and also the lower retaining rings  32 ,  34  each feature at least one valve  40 ,  48 , which are shown enlarged in  FIGS. 2 and 3 . 
   The valve  40  acts as a ventilation valve for the nonfiltrate chamber  19  and the lower valve  48  as a supply valve for the nonfiltrate material into the nonfiltrate chamber  19 . The valves  40 ,  48  each have a valve cover  42 ,  50  with a valve tappet  44 ,  52 . The valve covers  42 ,  50  are connected to the corresponding retaining ring  32 ,  34  over a spring  46 ,  54 . 
   The valve cover  50  of the inlet valve  48  is arranged in the nonfiltrate chamber  19  and seals the valve opening  38  when the filter module is removed from the filter housing  2 . In the installed state, the valve tappet  52  contacts a projection  80  (see  FIG. 3 ), so that the inlet valve  48  in the installed state is always located in the open position and thus the inflow of nonfiltrate material into the nonfiltrate chamber  19  is not impaired. 
   The valve cover  42  is also found in the nonfiltrate chamber  19 . In the installed state, the valve  48  is open, so that the air present while the nonfiltrate material flows into the nonfiltrate chamber  19  can escape to the outside through the ventilation channel  128   a, b . As soon as the nonfiltrate chamber  19  is filled with nonfiltrate material, a valve, which is arranged on the outlet  130  but is not shown, can then be closed. 
   Additional adapter valves  90 ,  100  are arranged in the two adapters  24  and  26 . 
   The upper adapter valve  90  (see  FIG. 2 ) has a valve ring  92 , which is inserted in the upper adapter  24  in a sealed fashion. The valve ring  92  has an annular valve opening  95 , which can be sealed by a valve plate  94  with valve tappet  96 . The valve plate  94  projects into the filtrate channel  18  and then closes the valve opening  95  when the filter module is removed from the filter housing  2 . In the installed state, as illustrated in  FIG. 2 , the valve tappet  96  contacts the distributor head  120 , so that the valve opening  95  is opened. 
   The adapter valve  100  (see  FIG. 3 ) in the lower adapter  26  is installed correspondingly, with the valve plate  104  likewise projecting into the filtrate channel  18 . The valve plate  104  is similarly arranged so that it closes the valve opening  105  when the filter module is removed from the filter housing  2 . The valves  90 ,  100 ,  40 , and  48  thus enable drip-free removal of the filter module. 
   To enable the installation of the filter module in a conventional filter housing, an installation set is provided, which is described in more detail in connection with  FIGS. 2 and 3 . 
   In  FIG. 2 , the upper components of the installation set are shown. The cover plate consists of an annular head plate  110 , whose outer contours, as shown in  FIG. 1 , are adapted to the inner contours of the housing cover wall  8  and the housing shell  10 . The lower side  112  of the head plate  110  forms a contact surface for the envelope  30 . Here, it is important that only a small distance is maintained to the housing shell  10  so that during the filtration the noncompression-proof envelope  30  cannot bulge out so far that it is damaged. Furthermore, the head plate  110  has a ring receiver  116  for the upper retaining ring  32 . 
   Furthermore, a distributor head  120  is inserted in the center in the head plate  110 . This distributor head extends upwards through the housing connection  6 . In the distributor head  120 , as can be seen in  FIG. 2 , there is a ventilation channel  128   a ,  128   b , which connects to the valve opening  36  of the valve  40  over the annular chamber  126 . Therefore, the air escaping from the nonfiltrate chamber can be discharged through the outlet  130  at the upper end of the distributor head  120 . In the region of the annular chamber  126 , a stop  124  is formed on the distributor head  120  for the valve tappet  44 , which holds the valve  40  in the open position in the installed state. The distributor head  120  further has an annular flange  122  for receiving the upper adapter  24 . 
   In the center in the distributor head  120 , there is a ventilation channel  132  with the channel branches  134   a  and  b , which connect to the filtrate channel  18 . 
   Furthermore, located in the distributor head  120  is a control channel  136 , which connects over the channel branches  138  and  140  to the intermediate spaces between the head plate  110  and the housing upper part  4  and thus also to the intermediate space between the envelope  30  and the housing shell  10 . If the envelope  30  is damaged, the nonfiltrate material would flow outwards through the channel branches  138 ,  140  and the control channel  136  and thus could be detected. 
   However, the control channel  136  can also be attached to a pressure device. If the pressure device is an overpressure device, e.g., compressed air can be blown into the channels  138 ,  140  so that the envelope is pressed against the filter cells  22 . This enables residual filtration to be performed at the end of filtration. 
   The control channel  136  can also be attached to a low-pressure device, so that the filling process at the beginning of filtration can be supported by suction in the envelope  30  up to the attachment to the housing wall. 
   As can be seen in  FIG. 3 , an annular base plate  60  is arranged between the base plate  12  and the filter module. The radial dimension of this base plate essentially corresponds to the inner dimension of the housing shell  10 . The base plate  60  has a surface  66 , which rises towards the outside in the radial direction and which forms a contact surface for the envelope  30 . Because the envelope  30  is not pressure-sealed, it is important that the base plate  60  extends as close as possible to the inner side of the housing shell  10 , so that the envelope  30  is not damaged in the transition region between the base plate and the housing shell by the inner pressure in the filter module. 
   The base plate  60  has a nonfiltrate channel  62  which connects the nonfiltrate supply  14  of the base wall  12  to the valve opening  38  of the valve  48 . The annular base plate  60  has a ring receiver for receiving the retaining ring  34  and carries a receiver bushing  70  arranged in the center for receiving the lower adapter  26 . The receiver bushing  70  has a lower bushing section  74  and an upper bushing section  72  that widens outwards in the radial direction for receiving the adapter  26 . An inner shoulder  76  and an outer shoulder  78  are formed by the radial offset. With the outer shoulder  78 , the receiver bushing  70  contacts a corresponding surface of the base plate  60 . The inner shoulder  76  is used to support the valve ring  102  of the adapter valve  100 . A projection  80  as a stop for the valve tappet  52  of the inlet valve  48  is arranged radially outwards on the upper bushing section  72 . The position of the projection  80  is selected so that the valve tappet  52  presses the valve cover  50  upwards, so that the valve opening  38  is opened. 
   In  FIG. 4 , another embodiment is shown which concerns the installation of two schematically illustrated filter modules. In order to be able to connect the two filter modules to each other, an intermediate plate  150  is provided with end surfaces  154 ,  156  as contact surfaces for the envelopes  30 ,  30 ′. The annular intermediate plate  150  receives the lower retaining ring  34 ′ of the upper filter module and the upper retaining ring  32  of the lower filter module. The intermediate plate  150  extends with its outer peripheral surface  152  into the vicinity of the inner surface of the housing shell  10 . Furthermore, the intermediate plate  150  has a ring element  160  for receiving the adapter  26 ′ and  24 . The valves  40  and  48 ′ are connected to each other over a connection channel  158 . A projection  162  of the ring element  160  projects into this connection channel and this projection acts as a stop for the valve tappet  52 ′ and  44 .

Technology Classification (CPC): 1