Abstract:
A self supported cylindrical corrugated filter. The corrugations of the filter define a first and second end. Two arcuate side walls join the first and second end. The filter has a substantially planar front surface and a substantially planar rear surface. The front and rear surfaces extend the length of the filter. The arcuate side walls have a plurality of overlapping folded flaps. Each one of the plurality of flaps is joined to at least one adjacent flap from the plurality of flaps to form the self supported filter.

Description:
This application claims priority from U.S. Application 60/610,984 filed Sep. 16, 2004, the entirety of which is incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   The present invention relates a filter element that is ultrasonically sealed to provide a self sealed cylindrical corrugated fluid filter. 
   DESCRIPTION OF RELATED ART 
   Cellulose air filters can be made according to our U.S. Pat. No. 5,178,760 wherein a cylindrical corrugated filter media has molded thereon in a sealing relationship a container, so that the assembly is ultimately sold as the an air filter element that can be used in a filter housing. 
   SUMMARY OF THE INVENTION 
   The present invention provides a self sealed cellulose based air or gas filter element which does not have a separate sidewall molded thereon and can be directly inserted into a filter canister. The filter element can also be described as a self supported filter cartridge or can be described as a self contained filter cartridge. 
   The present invention provides a self-supported cylindrical corrugated filter element having corrugations defining a first and second end, two arcuate side walls joining the first and second ends, a substantially planar front surface, a substantially planar rear surface, said front and rear surfaces extending the length of the filter, the arcuate side walls having overlapping folded flaps joined without the use of a separate applied adhesive, i.e. the flaps are ultrasonically welded to provide our self-supported filter cartridge or element. The flaps can thus be considered non-adhesively joined. 
   The present invention further provides the above self-supported cylindrical corrugated filter cartridge wherein on each side of the filter there is a first group of the overlapping flaps folded clockwise and a second group of the overlapping flaps folded counter-clockwise. 
   The present invention also provides the above described self-sealed cylindrical corrugated filter cartridge that has an indentation therearound spaced a predetermined distance form one end thereof to provide means for holding an o-ring type seal to permit the self-supported cylindrical corrugated filter cartridge to fit in a desired filter container or housing. 
   The present invention also provides an filter blank that can be ultrasonically welded to provide the above self-supported cylindrical corrugated filter cartridges. 
   The present invention also provides a method of preparing the self-supported cylindrical corrugated fluid filter by preparing an ultrasonically weldable filter blank that can be corrugated and formed into a substantially cylindrical filter, corrugating the blank to form a substantially cylindrical fluid filter media having two arcuate side walls with a plurality of corrugation ends, supplying a first ultrasonic welding retainer having first corrugation fingers, sized to fit the corrugations of at least some of the corrugations in one end of the substantially cylindrical filter element, supplying a second ultrasonic welding retainer having second corrugation fingers sized to fit the corrugations of at least some of the corrugations in the other end of the substantially cylindrical fluid filter, placing the first fingers into the corrugations in the one end of the substantially cylindrical air filter, placing the second fingers into the corresponding corrugations in the other end of the substantially cylindrical fluid filter, contacting the corrugation ends that have first and second fingers therein with an ultrasonic device such as an arm to fold the corrugation ends (flaps) to provide the overlapping side wall flaps and to ultrasonically weld the overlapping side wall flaps to provide the self-supported cylindrical corrugated fluid filter cartridge. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings are provided to illustrate some of the embodiments of the disclosure. It is envisioned that alternate configurations of the embodiments of the present disclosure may be adopted without deviating from the disclosure as illustrated in these drawings. 
       FIG. 1  discloses a top plan view of our self-supported cylindrical corrugated fluid filter cartridge having its filter media bordered by a pair of seals. 
       FIG. 2  discloses a side cross sectional view of the filter cartridge of  FIG. 1  taken along the view lines A-A. 
       FIG. 3  is a cross sectional view of  FIG. 1  taken along the view lines B-B. 
       FIG. 4   a  is a blow-up of the detail shown in  FIG. 3 . 
       FIG. 4(   b ) is the same as  FIG. 4  except using an O-ring seal. 
       FIG. 5  is a plan view of the filter blank used to prepare the filter of the present invention. 
       FIG. 6  is a top view of the filter media prior to folding and overlapping the ends of the corrugations. 
       FIG. 7  is an elevational side view of the filter of  FIG. 6 . 
       FIG. 8  is a representative view of the filter media positioned to be placed between a filter media retainer, wherein the end portions of the pleats forming the curvilinear perimeter of the filter media are to be folded over and welded to each other. 
       FIG. 9  is a top-sectional view showing the filter media mounted in the retainer, a welding horn is positioned to weld the open end portion of the pleats one to the other. 
       FIG. 10  is a perspective view of the lower retainer portion shown in  FIG. 9 ; 
       FIG. 11  is a perspective view of the welded filter element of  FIG. 1  illustrating the open end portions of the corrugations folded over and welded to each other; 
   

   DETAILED DESCRIPTION 
   Referring to the  FIGS. 1-4 , our self-supported cylindrical corrugated fluid filter cartridge  30  has an ultrasonic sealed corrugated filter media  31 . The filter media is preferably a cellulose based media that has some plastic mixed with the paper material to allow it to be bound to itself by ultrasonic welding. The filter cartridge or element  30  has corrugations defining an upper or first end  32  and a lower or second end  33 . The two ends are joined by two arcuate side walls  34  and  36  and a front planar portion  37  and rear planar portion  38 . The side walls are provided with a closed filter surface to substantially prevent air from freely passing through without being filtered. The closed filter surface is provided by having side walls comprised of ultrasonically welded overlapping flaps as hereinafter described. 
   As shown in  FIG. 4   a , the cartridge has a seal  40 . The seal  40  has an upper flange section  41  and a lower cylindrical body portion  42 . The seal  40  is generally fastened onto the media by press fitting thereon or alternatively also being attached by adhesive with or without the press fit. Our  FIG. 4(   b ) shows an alternative seal  43  that can be used. Seal  43  is an o-ring which is fitted into a groove formed on the cellulose side walls  34 ,  36  and front and rear walls  37 ,  38 . As stated above these seals permit our filter cartridge  30  to be tightly fitted into a fluid filter housing. Since our filter cartridge does not require a separate plastic side wall before it can be used, it is highly economical and environmentally friendly. 
   Referring to  FIGS. 5-10  there is shown how our filter cartridge is manufactured.  FIG. 5  shows a flat filter member  50  that tapers along both edges from its widest dimension at its midsection toward its opposite ends  52  and  53 , which are rounded to form a tongue-like flange. The illustrated blank is merely representative and is not to the scale of the folded filter elements  50  shown in  FIGS. 6 and 7 , however, the transverse lines  54  shown in  FIG. 5  are representative of fold lines for lower folds  55  and upper folds  56 . The distance indicated by the arrows B-B in  FIG. 5  is representative of the amplitude or height of the folds and will be strongly controlling in determining the total area of the filter element. 
   Referring to  FIGS. 6 and 7  the blank  50  is appropriately folded to form the cylindrical filter element  57  that has the end tongue-like flanges  52  and  53 . 
   Referring to  FIGS. 8 and 10  suitable filter retainers or cores  60  and  61  are used to produce the cartridge  30 . The two filter cores are substantially identical and therefore only one will be described. Although two cores are used, it would be possible to use only one core.  FIG. 10  shows the lower or first ultrasonic welding core  60  having first corrugation fingers  62  sized to fit the corrugations formed by folds  55  and the second corrugation fingers  63  are sized to fit the corrugations formed by the folds  56 . The width, as measured along direction  100 , of the each of the fingers  62  and  63  are such that they are a predetermined amount less that of the width, as measured along direction  101 , of the respective folds  55  and  56 . Put another way, the diameter of the cellulose media is greater than that of the core. Therefore, hereinafter set forth, the ends of the corrugations formed by the folds can be folded to provide overlapping flaps that can be ultrasonically welded. As previously noted, the blank  50  is preferably a cellulose based material such as paper that has a plastic thermo setting resin added thereto so that it can be bound to itself by ultrasonic welding. 
   To prepare the cartridge  30  the core fingers  62  and  63  are placed into opposite ends of the filter element  57  as shown in  FIG. 8 . When they are fully inserted, the filter element is thus intermeshed and sealed between both the fingers  62  and  63  of the lower and upper retainer cores. The upper and lower fingers  62  and  63  are thus only separated by the thickness of the filter media and leave unengaged corrugations ends  75   a . As illustrated in  FIG. 9 , the retainer/positioner cores  60  and  61  rotate and an ultrasonic welding device, has a welding arm and a ultrasonic welding horn head  70  that indexes in and out causing the horn to fold over the open end portions of the filter element  57 . Thus the ends of the filter element  75   a  extending beyond the ends of the fingers  62  and  63  are folded over and the folds overlap each other and the overlapping folds are sonically welded one to the other by the ultrasonic welding horn which is adjacent to the perimeter of the cylindrical retainer/positioner cores to produce the ultrasonically welded filter cartridge  75  having the welded flaps  75   b  are shown in  FIG. 11 . 
   A second material may be wrapped around the sealed side walls and front and rear walls and welded thereto to make the formed media more rigid and visually appealing. 
   As an example of our filter  30  the diameter of the flange  41  is about 594 mm, the length of the filter from its top to its bottom is about 83 mm, the distance between the flange top surface and the top of the filter is about 8 mm, the thickness of the flange is about 57 mm, and the diameter of the filter element  75  is about 550 to 563 mm. 
   The filter paper utilized is between 99% and 99.7% efficient at two (2) microns. The filter paper should be cut and fabricated such that it has a ratio of cubic meters per hour/square meter of between 370 and 555 while providing a pressure drop below 250 pascals or 2.5 milibars. The paper should be able to accommodate a flow rate of air between 416-3000 cubic meters per hour. The filter paper is formed from a cellulose media having sufficient thermo resin to allow for proper ultrasonic welding. 
   Of course, other modifications than those discussed above may be used in producing a self-supported cylindrical corrugated fluid filter without departing from the scope of the accompanying claims. Also unless limited by the prior art the term cylindrical is meant to cover any shaped filter which is to be used as an air intake filter that is to be inserted in a an apparatus the utilizes a closed air intake filter holder.