Patent Abstract:
A filter bag support structure, including a first section and a second section. The first section includes a pair of opposed alignment members located partially internal to the first section and extending outwardly away from the first section aligned to insert into the second section. The second section includes at least one annular member. The alignment members are receivable within the second section and have engagement members near a distal end. A locking member is removeably insertable between the opposed alignment members and inhibits the alignment members from flexing inwardly when the locking member is inserted and causes the alignment members to resist being removed from the at least one annular member when a tension load is applied that would tend to separate the first section from the second section to a greater degree than when the locking member is not present.

Full Description:
FIELD OF THE INVENTION 
     The present invention relates to an air filtration system suitable for use within the ventilation system of a building. More particularly, the invention relates to improved filter cages used for supporting elongated filtration bags or socks within such a filtration system and securing filter cage sections together. 
     BACKGROUND OF THE INVENTION 
     Air filtration systems utilized in large ventilation systems often employ banks of elongated filtration bags or socks supported by wire filter cage assemblies. The filtration bags are positioned over the filter cages and remove particulates from the air circulated through the bag. The wire filter cages support the bags and prevent the bags from collapsing as air is drawn through the bags. Filter media exclude particulates from passing through the bag along with the air, and the particulates accumulate on the outside of the bags as air is drawn through the bag and filter cage combination. 
     Wire filter cages supporting filtration bags are commonly used in large-scale filter assemblies. A large-scale filter assembly structure includes a large enclosure. The large enclosure is divided by a horizontal partition plate that separates an upper clean air compartment from a lower dirty air compartment. The partition plate is formed with a large number of openings arranged in a pattern. Each such opening supports a wire filter cage and its associated fabric filter bag. Thus, the air flow passes from the lower dirty air compartment through the suspended filter bags and wire filter cages through the openings in the partition plate and into the upper clean air compartment. 
     Filter bags are periodically cleaned by shaking or by creating a backflow of air from the inside of the filter bags outward. After an extended period of use it becomes necessary to remove the filter cages and filter bags from the partition plate in order to replace the filter bags. If a one-piece filter cage is employed it is necessary that the upper clean air compartment have sufficient overhead height for the entire length of the filter cage to be accommodated when it is lifted from the horizontal partition plate. Wire filter cages are commonly as long as 26 feet. Some reach lengths of 29 feet. Thus, it is preferred, with lengthy filter cages, that the filter cages be partitioned into two or more sections to allow for a shorter overhead height in the clean air compartment. This shorter overhead height can result in large cost savings in material and construction of large filter assemblies. 
     Fine dust can form an explosive mixture with air. Air filtration systems are vented to prevent an accumulation of fine dust at a concentration that supports explosive combustion. Larger collector volume requires a greater vent area. A reduction in overhead height and consequently volume in the upper compartment leads to a lower venting cost and associated operating cost. 
     A variety of techniques have been used to connect multiple sections of wire filter cages. Wire filter cage section connections should be secure and easily assembled and disassembled. In addition, it is desirable that the inner connections be made without leaving any exposed wire ends or other sharp structures. Fabric filter bags are relatively vulnerable to puncture or tearing. If they are snagged on exposed wire ends they may be torn thereby causing particulate leaks and requiring replacement of the bags sooner than would otherwise be necessary. 
     SUMMARY OF THE INVENTION 
     The approach to connecting wire filter cage sections disclosed in U.S. Pat. No. 5,173,098, issued to Pipkorn, reveals a connection technique utilizing two sheet metal sleeves and two wire clips. This approach provides an interconnection that is relatively easy to assemble and disassemble. However, under significant longitudinal tension loads the wire clips fail to hold the filter cage sections together. Lower filter cage sections sometimes separate from upper filter cage sections and drop to the floor of the lower dirty air compartment. En route to the floor, the separated lower filter cage sections tear through the associated filter bag destroying the filter bag. Further, upon impacting the floor of the dirty air compartment, the lower filter cage sections are often damaged to a degree that makes them unusable. The damaged filter cage sections as well as the filter bags then must be replaced. 
     Other approaches to connecting wire filter cage sections are disclosed in U.S. Pat. Nos. 6,626,970, 6,790,250, 6,905,529 and 7,371,267 issued to Howard Pipkorn and Kal Ugargol which are commonly assigned with this patent application. The filter cage sections include guide members that extend into an adjacent cage section and resiliently engage wire hoops of the adjacent filter cage thereby securing the adjacent filter cage sections together. 
     Filter cages designed according to these approaches include formed wire guides to create a snap latch joint. The wire guides protrude from the interior of a first wire filter cage section. 
     The wire guides are inserted into the open end of a second wire filter cage section to join the sections. When the two sections are assembled together on a common axis, the resistance to bending of the wire guides presses the ends of the wire guides against the annular rings of the second wire filter cage, thus aligning the two cages axially and holding the two cages snugly together. 
     Assembled filter cage sections can be subject to unusually high tension loads during handling and installation. Laborers who install new filter bags sometimes drop the filter cages from a significant height into the openings in the horizontal partition plate which then stops the descent of the filter cage when the top retention structure of the filter cage impacts the horizontal partition plate. The inventors estimate that the tension impulse load on the filter cage joints where the sections are joined exceeds three thousand five hundred pounds when the assembled filter cage is dropped from a height of four feet and strikes the partition plate. This separates the filter cage sections and leads to the damage to filter bags and fallen filter cage sections discussed above. The invention solves many of these problems. 
     Referring to  FIG. 1 , a prior art filter cage as disclosed in U.S. Pat. No. 5,173,098 is depicted. The prior art filter cage includes sheet metal sleeves and wire clips to align and secure the filter cage sections to one another. The summary of the invention and detailed description of U.S. Pat. No. 5,173,098 are hereby incorporated by reference in their entirety. 
       FIG. 2  depicts a prior art wire guide filter cage including wire guide structures which are used to align and join to filter cage sections. Such a wire guide filter cage is disclosed in U.S. Pat. No. 6,905,529. The summary and detail description and drawings of which are incorporated herein by reference in their entirety in this application. 
       FIG. 3  depicts an example of wire guide filter cage with lock member in accordance with the present invention. A lock member is secured between either the sleeves depicted in the prior art of  FIG. 1 , or the wire guide depicted in the prior art of  FIG. 2  to secure the sleeves or wire guides to prevent their inward displacement, thereby securing the sleeve members or wire guide members coupling a first wire filter cage section and a second wire filter cage section from separating when an unusual longitudinal tension load is applied to the joint. 
     In one embodiment of the invention, a filter cage lock is inserted between the resilient wire guides of the filter cage and rotated approximately 90° to secure it in place between the resilient wire guides, thus inhibiting the resilient wire guides from flexing inwardly to release the related filter cage section. The rotation of the filter cage lock may be accomplished by hand or with a tool in accordance with the invention. When disassembly of the filter cage section is desired, the filter cage lock may be rotated again approximately 90° and released from between the resilient wire guides. The filter cage lock may then be removed to allow easy disassembly of the filter cage sections. 
     In another embodiment of the invention, the filter cage lock is adapted to be placed between sheet metal sleeves that have been modified to include engagement dimples on the sheet metal sleeves. In this embodiment as well, the filter cage lock is place between the sheet metal sleeves and rotated approximately 90° to secure the sheet metal sleeves to prevent inward flexing of the sleeves, thereby preventing unintended release of the filter cage sections. When it is desired to release the filter cage sections joined with the sheet metal sleeves, the filter cage lock can again be rotated approximately 90° to release it and then the filter cage lock can be removed from between the sheet metal sleeves facilitating separation of the filter cage sections. 
     The engagement dimples on the filter guide sleeve can be made by, for example, welding structures to the surface of the sheet metal sleeve, stamping the dimples on a metal stamping press to raise the surface of a sheet metal sleeve or by forming the sheet metal sleeve to have a ridge or bead. 
     In one embodiment of the invention, which is secured by rotation within the filter cage alignment members, the filter cage lock may have a polygonal configuration. In another embodiment, the filter cage lock may have a race track shaped configuration. In another embodiment, the filter cage lock may have dog bone shaped configuration. In another embodiment, the rotating filter cage lock may have a dome end configuration. 
     In accordance with other embodiments of the present invention, the filter cage lock may be secured in place by means other than rotation. For example, one embodiment of the present invention includes a turnbuckle, which can be used to separate two contact members to secure the contact members against the inside of the resilient wire guides or the resilient sheet metal sleeves. 
     In another embodiment of the present invention, two contact members may be coupled to an over-center mechanism which can be used to lock the contact members in an outward position against the interior of the resilient sheet metal sleeves or the resilient wire guides. 
     In another embodiment, the filter cage lock includes a bent clip filter cage lock. The bent clip filter cage lock is shaped to snap between the resilient wire guides or the resilient sheet metal sleeves of the filter cage sections. 
     In another embodiment, the filter cage lock may be structured as a linear clip filter cage lock. The linear clip filter cage lock may be formed of, for example, steel or aluminum channel having curved retainers at each end to couple with the resilient wire guides of the filter cage sections. 
     In another embodiment of the filter cage lock, the filter cage lock may be secured in a hinged fashion from one of the resilient wire guides or one of the sheet metal guides. 
     In another embodiment, the invention further includes a filter cage support and filter cage lock loss protector. The filter cage support and filter cage lock loss protector is structured to be insertable through the filter cage body to support the filter cage sections with a portion of it extended above and a portion of it extending below the horizontal partition plate of the filter assembly. The filter cage support and lock loss preventer further reduces the risk that filter cage locks that are dropped within the filter cage will fall down the filter cage to a location below the horizontal partition. 
     In one embodiment, the filter cage support and lock loss protector comprises a horizontal structure having several finger members that extend through the width of the filter cage. 
     In one embodiment, at least one of the finger members may have bent down portion to provide additional support for the filter cage and to prevent the filter cage support and lock loss protector from being inadvertently removed from within the filter cage. The filter cage support and lock loss preventer may also include a handle to facilitate handling by laborers utilizing it. 
     In one embodiment of the invention, the invention further includes a filter cage lock installation and removal tool. The filter cage lock installation and removal tool is a pry bar having a curved or retaining end adapted to assist in rotation of the filter cage lock. 
     In use, the filter cage lock is secured between the filter cage guide members whether they are sheet metal or wire guide members, after the filter cage sections are assembled. The filter cage lock inhibits inward movement of the filter cage guide members thus securing the filter cage sections together with much greater strength than the filter cage guide members alone. 
     The filter cage support and lock loss preventer can be inserted through the filter cage and abutted against the horizontal partition of the filter structure to support the filter cage at a convenient height for a laborer inserting the filter cage lock and assembling the filter cage sections. 
     The inventors have demonstrated experimentally that use of the filter cage lock with filter cage sections creates a joint strong enough that the filter cages themselves structurally fail prior to the joint releasing inadvertently. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cutaway perspective view of a large-scale filter assembly that can utilize a plurality of wire filter cages in accordance with the present invention; 
         FIG. 2  is a perspective, partially cutaway view of two joined sections of a prior art filter cage including sheet metal sleeves; 
         FIG. 3  is a perspective view of two sections of the prior art filter cage of  FIG. 1  with the sections separated; 
         FIG. 4  is a perspective, view of two joined sections of a prior art filter cage including resilient wire guides and a cage lock in accordance with an embodiment of the present invention; 
         FIG. 5  is a perspective view of two joined sections of a filter cage and a polygonal filter cage lock and installation tool in accordance with an embodiment of the present invention; 
         FIG. 6A  is a cross sectional view of the filter cage and a polygonal filter cage lock and installation tool taken along section line  6 - 6  of  FIG. 5  with the filter cage lock partially installed in accordance with an embodiment of the invention; 
         FIG. 6B  is a cross sectional view of the filter cage and a polygonal filter cage lock and installation tool taken along section line  6 - 6  of  FIG. 5  with the filter cage lock installed in an installed position in accordance with an embodiment of the invention; 
         FIG. 7  is perspective view of two joined sections of a filter cage and a filter cage lock in an installed position in accordance with an embodiment of the invention; 
         FIG. 8  is a perspective view of two joined sections of a filter cage including sheet metal sleeves with a dog bone shaped filter cage lock in a partially installed position shown partially in phantom and detent dimples on the sheet metal sleeves in accordance with an embodiment of the invention; 
         FIG. 9  is a perspective view of the filter cage of  FIG. 8 , a filter cage lock and installation tool in a partially installed position in accordance with an embodiment of the invention; 
         FIG. 10  is a perspective view of the filter cage of  FIG. 8  and a filter cage lock in an installed position in accordance with an embodiment of the invention; 
         FIG. 11  is perspective phantom view of a filter cage and filter bag with two sections joined and locked in accordance with an embodiment of the invention; 
         FIG. 12  is plan view of a dome end filter cage lock in accordance with an embodiment of the invention; 
         FIG. 13  is plan view of turnbuckle filter cage lock in accordance with an embodiment of the invention; 
         FIG. 14  is a plane view of dog bone shaped filter cage lock in accordance with an embodiment of the invention; 
         FIG. 15  is a plane view of a race track shaped filter cage lock in accordance with an embodiment of the invention; 
         FIG. 16  is a perspective view of an over center filter cage lock in accordance with an embodiment of the invention; 
         FIG. 17  is a perspective view of a bent clip filter cage lock in accordance with an embodiment of the invention; 
         FIG. 18  is a perspective view of the bent clip filter cage lock of  FIG. 17  installed in a filter cage in accordance with an embodiment of the invention; 
         FIG. 19  is a perspective view of a linear clip filter cage lock of  FIG. 17  installed in a filter cage in accordance with an embodiment of the invention; 
         FIG. 20  is a perspective view of the linear clip filter cage lock of  FIG. 17  installed in a filter cage in accordance with an embodiment of the invention; 
         FIG. 21  is a perspective view of a filter cage support and filter cage lock loss protector in accordance with an embodiment of the invention; 
         FIG. 22  is a perspective view of a filter cage lock installation tool like that depicted in  FIGS. 5 ,  6 A and  6 B in accordance with an embodiment of the invention; 
         FIG. 23  is a perspective view of a filter cage support, installation tool and filter cage lock loss protector in use in accordance with an embodiment of the invention; 
         FIG. 24  is a cross sectional view of a filter cage support, installation tool and filter cage lock loss protector in use taken along section line  24 - 24  of  FIG. 23  in accordance with an embodiment of the invention; 
         FIG. 25  is a cross sectional view of the filter cage support, installation tool and filter cage lock loss protector in use showing the loss protector stopping the loss of the filter cage lock in accordance with an embodiment of the invention; 
         FIG. 26  is a perspective view of the filter cage support, installation tool and filter cage lock loss protector in use showing the loss protector stopping the loss of the filter cage lock in accordance with an embodiment of the invention; and 
         FIG. 27  is a perspective view of an engagement dimple in a sheet metal sleeve in accordance with an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , a plurality of filter elements are depicted as installed in an air filtration unit  11 . The air filtration unit  11  broadly includes plenum enclosure  12 , base frame  14 , air filtration assembly  15 , filtered exhaust duct  16 , and air intake duct  17 . Air filtration unit  11  is utilized, for instance, in power or nuclear plants, coal dumping facilities, grain handling facilities and buildings where refining operations may take place. Typical ventilation systems used in these environments may range in height from fifty to one hundred feet. An access ladder  18 , surrounded by safety cage  20 , leads up to catwalk  22 , provides access to plenum enclosure  12  through access door  24 . Filtered exhaust duct  16  and air intake duct  17  may be attached to an integral with plenum enclosure  12 . Air filtration assembly  15  is positioned within plenum enclosure  12 . Plenum enclosure  12  is positioned on base frame  14 . 
     Base  14  may include frame  30 , legs  32 , and braces  34 . Base  14  may vary in size and proportion, depending on the size of the plenum enclosure  12  to be supported on base  14 . Base  14  can be made of a variety of high strength, durable materials such as structural steel. 
     Plenum enclosure  12  may be a large, generally cylindrical structure, ranging from twenty-five to fifty feet in height. Plenum cover or roof  36  is positioned over plenum enclosure  12 . Dust collection funnel  38  tapers downwardly toward dust discharge mouth  40 . The funnel  38  is positioned underneath plenum enclosure  12 , residing within the space below base frame  30  and between legs  32  and braces  34 . 
     Air filtration assembly  15  is contained mainly within plenum chamber  42 . Air filtration assembly  15  comprises an air pressure pump  44 , pressurization nozzle input duct  46 , nozzle arm  48 , and numerous filter elements  50  having air permeable hanging filter media bags or socks  52  surrounding filter cages  54 . In a typical large capacity air handling system, often employing multiple air filtration units  11 , tens of thousands of filter bags  52  and tens of thousands of wire filter cages  54  may be utilized. Air pressure pump  44  is connected to nozzle duct  46 . Nozzle arm  48  is positioned beneath nozzle duct  46 , and has air nozzles  56  opening in a downwardly direction, directed toward filter elements  50 . 
     Filter media bags or socks  52  are attached to filter cages  52 . Filter cages  54  rest on and are supported by bag hanger deck  62 . Filter media bags  52  are positioned over and supported by wire filter cages  54 . Unfiltered air enters air filtration unit  11  through intake duct  17  so as to be processed through air filtration assembly  15 . Filtered air is expelled from air filtration unit  11  through filtered exhaust duct  16 . 
     Referring to  FIG. 2 , an example prior art filter cage  54  and filter bag  52  are depicted. Filter cage  54  generally includes first section  300  and second section  302 . First section  300  includes sheet metal sleeves  304  attached thereto. Second section  302  includes wire clips  306  articulated therefrom. Referring to  FIG. 3 , sheet metal sleeves  304  are used to align and couple first section  300  to second section  302  and first section  300  and second section  302  are secured by wire clips  306 . 
       FIG. 4  depicts a filter cage  54  including resilient wire guides  308  and filter cage lock  310  in accordance with the invention. Filter cage  54  generally includes longitudinal members  312  and annular members  314  in addition to wire guides  308 . Annular members  314  may include an annular member  316  which is of larger size than remaining annular members  314 . Annular members  314  define the cross sectional shape of the filter cage and may be circular, oval, racetrack shape polygonal or any other shape. Generally, filter cage  54  is formed of metal wires. However, it is specifically contemplated that the invention disclosed here may be used with any type of filter cage or filter support. Examples include but are not limited to filter cages made from plastics, composites and perforated sheet materials. 
     Wire guides  308  and sheet metal sleeves  304  may be collectively referred to as alignment members. The term alignment members is not, however, limited to only to wire guides  308  and sheet metal sleeves  304 . 
     Wire guides  308  extend outwardly from the end of first section  300  and are structured to engage second section  302  at one of annular members  314  of second section  302 . Wire guides  308  may have rounded ends  318  as depicted in  FIG. 4  or may have ends of a variety of shapes as disclosed in U.S. Pat. No. 6,626,970, 6,790,250, 6,905,529 or 7,371,267, the drawings, summary and detailed descriptions of which are hereby incorporated by reference. 
     Referring to  FIGS. 4 and 5 , cage lock  310  is depicted in  FIG. 4  prior to being installed completely. Cage lock  310  is depicted in  FIG. 5  partially secured.  FIG. 5  further depicts an example embodiment of installation tool  320 . Installation tool  320  is structured to assist in rotating cage lock  310  into the secured position and to assist in removing cage lock  310  from the secured position. 
     Referring to  FIG. 6   a , cage lock  310  is depicted as engaged by installation tool  320  at the beginning of the installation process. Referring to  FIG. 6   b , cage lock  310  is depicted along with installation tool  320  in an installed position.  FIG. 7 , depicts an example cage lock in a perspective view in the installed position. 
     Referring to  FIG. 8 , an example embodiment of cage lock  310  is depicted along with filter cage  54  including sheet metal sleeves  304  in accordance the present invention. Sheet metal sleeves  304  include engagement dimples  322 . Engagement dimples  322  are positioned on sheet metal sleeves  304  to engage annular member  314  to assist in securing first section  300  to second section  302 . Engagement dimples may be formed by structures which protrude from the outer surface of sheet metal sleeves  304  by forming a protrusion on sheet metal sleeves  304  or by dimpling metal sleeves  304  with a punch or press.  FIG. 8  also depicts cage lock  310  in accordance with the present invention. 
       FIG. 9  depicts rotation of cage lock  310  in cooperation with sheet metal sleeves by installation tool  320 . 
     Referring now to  FIG. 10 , cage lock  310  is depicted in an installed position. 
       FIG. 11  depicts cage lock  310 , in phantom, in an installed position within filter cage  54  covered by filter bag  52 . As can be understood from  FIG. 11 , cage lock  310  has minimal effect on air flow through filter bag  52  and filter cage  54 . 
     Cage lock  310  may include a variety of embodiments including rotating cage lock  324 , turnbuckle cage lock  326 , bent clip cage lock  328 , linear clip cage lock  330  and over-center cage lock  332 . 
     Rotating cage lock  324  may include polygonal cage lock  334 , dog bone cage lock  336 , dome end cage lock  338  and race track cage lock  340 . This list should not be considered limiting. All of the embodiments of rotating cage lock  324  are installed and removed generally as depicted in  FIGS. 4 ,  5 ,  6   a ,  6   b ,  7 ,  8 ,  9  and  10 . Referring to  FIGS. 4 ,  5 ,  7  and  10 , polygonal cage lock  334  in one example embodiment can be made in a generally octagonal shape. 
     Referring to  FIGS. 8-10  and  14 , dog bone cage lock  336 , in an example embodiment, includes two linear sections  342  and two circular sections  344 . Circular sections  344  may be of other rounded shapes besides perfectly circular. 
     Referring to  FIG. 12 , dome end cage lock  338  includes two linear sections  346 , two dome sections  348  and steps  350 . 
     Referring to  FIG. 13 , turnbuckle cage lock  326  generally includes turnbuckle  352  and contact portions  354 . Turnbuckle  352  is configured to expand and retract contact portions  354  upon actuatation of turnbuckle  352 . 
     Referring to  FIG. 15 , race track cage lock  340  assumes a generally oval or race track shaped configuration. 
     Referring to  FIGS. 17 and 18 , bent clip cage lock includes linear portion  356 , long leg  358  and short leg  360 . Each of long leg  358  and short leg  360  include indentation  362 . 
     Referring to  FIGS. 19 and 20 , linear clip cage lock  330  generally includes channel portion  364 , curve legs  366  and wire guide receivers  368 . Box or channel portion  364  may be formed of steel or aluminum channel, square section tubing or a solid bar for example. Curved legs  366  in cooperation with wire guide receivers  368  are dimensioned to receive the wires of wire guides  308  or a portion of sheet metal sleeve  304  when installed. In one example embodiment, linear clip cage lock  330  may be hingedly secured to one of wire guides  308  or sheet metal sleeves  304 . 
     Referring to  FIG. 16 , over-center cage lock  332  generally includes over-center mechanism  370  and contact portions  372 . Over-center mechanism  370  is structured to expand contact portions  372  into contact with sheet metal sleeves  304  or wire guides  308 . 
     Any of the various embodiments of cage lock  310  may be utilized to secure either wire guides  308  or sheet metal sleeves  304  in the context of coupling first section  300  with second section  302  of filter cage  54 . 
     Referring to FIGS.  21  and  23 - 26 , filter cage support and lock loss protector  374 , in an example embodiment, generally includes handle  376 , fingers  378  and cross member  380 . Handle  376  is depicted here as being circular but can be of any shape convenient for the purpose. Fingers  378  are positioned to define slots  382  therebetween. Fingers  378  are structured to fit through open portions of filters cage  54 . Optionally, fingers  378  may include at least one bent finger  384 . Bent finger  384  is adapted to prevent the unintended withdrawal of loss protector  374  from within a filter cage by engaging one of annular members  314 . 
     As depicted in  FIGS. 23-26 , loss protector  374  assists in supporting filter cage  54  while cage lock  310  is installed or removed. Loss protector  374  also assists by reducing the likelihood that cage lock  310  can fall down the length of filter cage  54  to the bottom of filter bag  52 , thus becoming difficult to retrieve. 
     Referring to  FIGS. 5 ,  6   a ,  6   b ,  9  and  22 , installation tool  320  generally includes handle portion  386  and curved end  388 . Curved end  388  is adapted to grip cage lock  310  to assist in positioning it. 
     In operation, referring to  FIGS. 4 ,  5 ,  6   a ,  6   b ,  7 ,  8  and  9 , rotating cage lock  324  is inserted between wire guides  308  or sheet metal sleeves  304 . Rotating cage lock  324  is then rotated by hand or with the assistance of installation tool  320  into a position generally perpendicular to the longitudal axis of wire filter cage  54 . Rotating cage lock  324  then resists or inhibits inward deflection of sheet metal sleeves  304  or wire guides  308 , thus providing a coupling between first section  300  and second section  302  that is highly resistance to impulse loads under tension. Thus, the application of cage lock  310  prevents the unintended separation of first section  300  from second section  302 , thus preventing damage to filter bags and filter cages. As discussed above, unintended separation of first section  300  from second section  302  can occur when filter cage  54  is subjected to dropping. 
     Referring to  FIG. 13 , in operation, turnbuckle cage lock  326  is inserted between sheet metal sleeves  304  or wire guides  308 . Turnbuckle  352  is then rotated to force contact portions  354  outward against sheet metal sleeves  304  or wire guides  308 , thus inhibiting inadvertent separation of first section  300  from second section  302  under load. 
     Referring to  FIGS. 17 and 18 , bent clip cage lock  328  is inserted between sheet metal sleeves  304  or wire guides  308  to prevent inward deflection of sheet metals sleeves  304  or wire guides  308 , thus securing first section  300  to second section  302  against tensions loads. 
     Referring to  FIGS. 19 and 20 , linear clip cage lock  330  is inserted between sheet metal sleeves  304  or wire guides  308  to prevent inward deflection of sheet metals sleeves  304  or wire guides  308 . 
     To accommodate linear clip cage lock  330 , sheet metal sleeves  304  may have apertures cut in them to receive linear clip cage lock  330 . In one example embodiment, linear clip cage lock  330  may be attached to one of wire guides  308  by bending one of curved legs  366  around wire guide  308 . Thus, linear clip cage lock  330  may be hingedly attached to one of wire guides  308  or sheet metal; sleeves  304 . 
     Over-center cage lock  332  may be inserted between sheet metal sleeves  304  or wire guides  308  and over-center mechanism  370  actuated to force contact portions  372  outward into wire guides  308  or sheet metal sleeves  304 , thus preventing inward deflection of wire guides  308  or sheet metals sleeves  304  to secure first section  300  to second section  302 . 
     Referring to FIGS.  21  and  23 - 26 , filter cage support and lock loss protector  374  can be inserted between longitudinal members  312  of filter cage  54  and abutting one of annular members  314 , thus preventing filter cage  54  from dropping through hanger deck  62 . As depicted in  FIGS. 24 through 26 , loss protector  374  inhibits cage locks  310  from falling down filter cage  54 . 
     Referring to  FIG. 27 , engagement dimples  322  may be formed as punch dimple  390  by applying a punch partially through sheet metal sleeves  304 . 
     The present invention may be embodied in other specific forms without departing from the spirit of the essential attributes thereof; therefore, the illustrated embodiments should be considered in all respects as illustrative and not restrictive, reference being made to the appended claims rather than to the foregoing description to indicate the scope of the invention.

Technology Classification (CPC): 1