Patent Document

RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 09/660,969 filed on Sep. 13, 2000, now U.S. Pat. No. 6,568,539, which is a divisional of U.S. patent application Ser. No. 09/373,438, filed on Aug. 11, 1999, now U.S. Pat. No. 6,221,242, which is a continuation-in-part of U.S. patent application Ser. No. 08/951,387, originally filed on Oct. 16, 1997, now U.S. Pat. No. 6,228,274, which claims the benefit of U.S. Provisional Application, Serial No. 60,033,387 filed on Dec. 17, 1996. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to filtering devices. In particular, the present invention relates to a renewable spin-on type filter having a high strength plastic housing. 
     2. Discussion of Background 
     Spin-on, twist-on type filters are used in numerous liquid and pneumatic applications throughout the agricultural, transportation, commercial and industrial markets. The housing or can for most spin-on disposable filters are manufactured from malleable materials, such as aluminum, by a deep-draw forming process. This technique limits the structural capabilities of current spin-on and twist-on type disposable products to the production capabilities of the metal forming industry and to the molecular characteristics of a limited number of specific malleable metals. Prior art disposable filters use stamped steel or cast cover plates to secure the housing or can to a mounting and distribution head assembly. This plate typically has a threaded center hole and is spot-welded and/or crimp-sealed to a deep drawn can. The purpose of the cover plate is to provide a mounting section that contains sufficient strength to allow operation of the filter at the required pressure rating. These prior art techniques for sealing and connecting the can to the plate, plus the structural limits of thin gauge malleable metals, restrict the application and uses of prior art spin-on, twist-on disposable filters. Recently, new high pressure, high burst strength disposable filter housings with burst pressure ratings in the 1000 psi range have been developed for some narrowly defined markets and applications. However, even these newer, high-strength filters remain applicationally limited because of their continued use of deep-drawn metal cans. 
     The filter media used in the prior art are usually paper products that are flexible and flimsy. As a result of their flexible and flimsy characteristics, these filters often are not properly secured in place within the housing or can during the assembly of the filter. By some accounts, 50% of current commercially available oil filters are defective and thus do not perform up to specification. Also, prior art paper filters often develop rips or tears during use. For example, if there is a spike in the pressure of the fluid being filtered, paper filters will often develop a rip through which unfiltered fluid flows. Such rips generally increase in size as a result of the rush of fluid flow there through. Such defects are not visible and unknown to the machine operator and the use of the filter continued for its normal use period during which improperly filtered oil is re-circulated through the machine or engine. Serious damage to the machine or engine can result. Once these disposable filters have been severed, they can no longer serve their purpose and should be replaced. 
     When conventional filters reach the end of their useful life, the filter is removed from the vehicle or machine and the remaining filtrate, usually oil, is drained and a new filter is installed. Thereafter, the filter should be compacted and disposed of in accordance with industry practice. However, often the used filter is disposed of in a way that it is eventually placed in a land fill. The impact on the environment from the disposal of used filters and oil is devastating to the environment. The enormity of this problem is realized when the variety of industrial and consumer applications that employ disposable filters, as well as the frequency with which these filters are replaced, is considered. The impact on the environment can be appreciated when it is realized that there are currently about 180,000,000 vehicles in the United States for which it is recommend that the filter and oil be changed every 3,000 miles. About 400,000,000 oil filters are manufactured in the U.S. each year, of which less than 25% are properly recycled. The remaining, which retain some oil, are disposed of and this used oil enters the environment. Even properly drained oil filters can retain up to 8 ounces of used oil. It is estimated that the result of proper recycling would result in the recovery of more than 17,000,000 gallons of oil. If properly processed, this oil could be reused. 
     Therefore, there exists a need for a twist-on filter that is renewable which would support and encourage the recycling of used oil and reduce environmental liability. 
     If an oil filter is not serviced, it can become clogged and the flow of incoming oil will be impeded and eventually completely stop from passing through the filtering media. When the filter becomes blocked with contaminates, fluid flow is restricted and diminished and the differential pressure across the filter element increases. As the volume of the flow diminishes, parts of the machine or engine that normally receive lubrication will receive inadequate lubrication. The typical lubrication systems for an internal combustion engine pump oil from a sump through a loop, splashing oil over and around moving engine parts, such as the valves and piston rods. The oil filter is a component through which the oil flows in this oil flow loop. Thus, if the oil filter becomes clogged, the flow of oil is impeded and lubrication becomes inadequate. However, the damage to an engine or machine will be less if the circulation of the contaminated oil is continued rather than allowing the circulation of oil to be stopped. Thus, it is important that a bypass be provided to allow the circulation of oil to continue when it cannot pass through the filter media. Also, when an engine that is in a cold environment is started, the viscosity of the crankcase oil is very high and resists being forced through the filter media. It is important, in such situations, that provisions are available to allow the oil to bypass the filter for a period while its temperature increases and its viscosity decreases. For these reasons, oil filters should have a bypass system to protect the engine in the event of a clogged filter. Bypass valves for oil filters are known. However, they are complicated, expensive and are not an integral part of the filter. There is a need for a filter device that has a simple mechanical bypass that is an integral part of the filter device and cannot be disconnected or tampered with. 
     A typical automotive poppet type bypass valve has a very limited surface area against which the liquid that is at an elevated pressure must react to cause the bypass valve to open. This renders the valve unreliable for its intended purpose. Also, the typical automotive poppet type bypass valve utilizes a compression spring to urge the valve closed. Compression springs are very vulnerable to premature fatigue failure. The filter of this invention has an infinite life and, thus, if the filter of this invention is provided, a built-in bypass valve should also have an infinite life. Another shortfall of the typical automotive type poppet bypass valve of the type that relies on a compression spring to return the valve to its closed position is that it is unlikely that full closure will be attained. Coil type compression springs are rounded on both ends and cannot be properly guided. As a result, compression springs take the path of least resistance when they expand. Furthermore, coil type compression springs do not exert an equal pressure over the length of their expansion and, thus, do not provide a uniform pressure on the poppet valve. 
     Accordingly, there is a need for a simple bypass valve that is built into a renewable filter that has an infinite life cycle to match the life cycle of the renewable filter. There is also a need for a filter having a bypass valve that has a relatively large surface against which the liquid at elevated pressure reacts to increase the reliability of the valve. Still further, there is a need for a filter having a bypass valve that does not rely upon a coil type compression spring to close the valve. There is also a need for a renewable filter having an integral bypass valve that, when fully open, has the capacity to bypass the full volume of the normal oil flow. 
     SUMMARY OF THE INVENTION 
     According to its major aspects and briefly stated, the present invention is a renewable twist-on filter that is made from a sealed polymeric, unitary housing that has a filter media assembly securely bonded in place within the interior of the housing. After a use period that can be measured either in elapsed time or, for automotive uses, in miles traveled, the filter will be removed and replaced. The filter that has been removed will then be cleaned, after which it is put back into circulation for another use period. The filter housing is plastic welded together and, thus, would be destroyed if it is opened or tampered with. The filter is designed to last for an unlimited time and is designed to withstand pressures in excess of three times the normal operating pressure that it is expected to be exposed to. In one embodiment of the invention, a bypass valve is built into the interior of the housing to allow circulation of the fluid to continue in the event, for example, that the filter becomes contaminated or in the event of a cold start. The filter housing carries a metallic adapter having machined threads for securing the filter housing to an engine or machine. Adapters can have internal or external threads and be of various sizes and thread types. It is also contemplated that this adapter could be formed of plastic material. 
     The housing formed from a hollow polymeric container. In a preferred embodiment, there is a polymeric container member having an open top and a polymeric top member that are plastic welded together to thus provide a closed housing having an interior chamber. The filter media is fabricated from multiple layers of metal mesh material and, thus, is a rigid stable item which assures that, in the assembly process, it is properly located. During the assembly process, the filter media is bonded in place within the interior chamber and its position within the chamber is assured by plastic welding of the container member to the top member. The assembly procedure guarantees the initial proper location of the filter media assembly and the plastic welding assures that this location will be maintained. Thus, the top member is fused to the hollow polymeric container and this assembly now functions as a closed housing having an interior chamber within which is securely attached the filter media assembly. It should be noted that, although the preferred embodiment discloses a housing formed from a cup-shaped member that is closed by a disc-shaped top member, the top member need not be disc-shaped but rather could also be cup-shaped. It should also be noted that, although the hollow polymeric container or cup-shaped member is disclosed as being a unitary cast part, it could also be fabricated from a section of polymeric tube having a molded bottom end member bonded or welded thereto. The essential feature being that the components from which the hollow housing are formed are welded together to form a closed housing having an interior chamber within which is securely attached the filter media assembly. The filter media assembly is secured by adhesive at both ends within the housing such that the filter media assembly is immovable relative to the housing. The bottom of the filter media assembly is secured to the bottom or closed interior end of the housing by an adhesive material. The top of the filter media assembly is also bonded to a media collector plate that is connected to the inner surface of the top member. The filter media assembly divides the interior chamber of the housing into an inlet section and a discharge section. The filter media assembly could be any type that is commonly employed in the art provided it is capable of being cleaned and subsequently reused. 
     The preferred embodiment of the filter media assembly formed from three layers of metal mesh material. Each layer is cut to a shape having a pair of edges that, when joined by a weld or encapsulated by adhesive, cause the flat piece of material to assume the shape of a cone. The metal mesh material is folded or pleated radially such that, after the edges are joined, the filter is in the shape of a truncated cone having continuous top and bottom edges. The pleats extend from the top continuous edge to the bottom continuous edge. The surface area of the filter media assembly is greatly increased by such a filter design. The inner and outer metal mesh material layers are formed of relatively large stainless steel wire and have relatively large openings. These layers of metal mesh function mainly as supports and protection for the central layer which formed from much smaller wires and has very small filtering openings. An important function performed by the heavy gauge inner and outer layers is to assure that the pleats of the central layer do not collapse upon each other to form a double layer. 
     When the filter requires cleaning, it is removed from the distribution head of the vehicle or machine, and the excess fluid contained therein is drained out. This small amount of drained fluid can be easily disposed of in a manner that is not detrimental to the environment. Thereafter, the filter is back flushed using a cleaning solution. Once cleaned, the filter may be dried prior to reuse by allowing it to stand for a period of time or by blowing a drying gas therethrough. As a result of using the highly efficient and reliable filter, it is not necessary to change the oil each time the filter is cleaned. Test vehicles have currently exceeded 12,000 miles without an oil change and test of the oil shows little deterioration. 
     A major feature of the present invention is the unitary design of the polymeric housing. 
     Still another feature of the present invention is the combination of a polymeric housing and a renewable filter media assembly. This combination enables the filter to be cleaned and recycled which, in turn, significantly reduces the deleterious impact on the environment. 
     Another significant feature of this invention is the provision of a filter that has been provided having a bypass valve within the confines of the filter that requires no external conduits or accessories. This bypass valve, like the filter, has been designed for an infinite life cycle. The closure member for the bypass valve is maintained in a precise disposition as it is compressed as a result of it being guided by the outer surface of a brass adapter. This assures a full closure of the valve. Applicant&#39;s stainless steel spring engages the closure member at a plurality of equally spaced locations to exert a force on the closure member causing it to slide smoothly without binding along the smooth outer annular surface of the threaded adapter. As a result applicant&#39;s bypass valve will always return to its full closed position. The closure member of the bypass valve has a reaction surface area that is sufficient to insure that when fully open the bypass valve can bypassing the full volume of the normal oil flow. This is particularly important in cold start situations since it permits the full flow of unfiltered oil. 
    
    
     Other features and their advantages will be apparent to those skilled in the art from a careful reading of the detailed description of the preferred embodiments accompanied by the following drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a perspective view of an embodiment of the present invention; 
     FIG. 2 is a cross-sectional side view of the embodiment of the present invention taken along lines  2 — 2  of FIG. 1; 
     FIG. 3 is a perspective view of another embodiment of the present invention; 
     FIG. 4 is a cross-section view of the embodiment of the present invention taken along lines  4 — 4  of FIG. 3; 
     FIG. 5 is a cross-section view of the embodiment of the present invention taken along lines  5 — 5  of FIG. 3; 
     FIG. 6 is a top view of the embodiment of the present invention seen in FIG. 3; 
     FIG. 7 is an enlarged cross-section view of the embodiment seen in FIG. 3 of the top member at a location spaced above the hollow polymeric container; 
     FIG. 8 is an enlarged cross-section view of a portion of the top member at a location spaced above the hollow polymeric container showing another embodiment of the connection between the top member and the hollow polymeric container; 
     FIG. 9 is a top view of the top member for the preferred embodiment; 
     FIG. 10 is a bottom view of the top member for the preferred embodiment; 
     FIG. 11 is a cross-section view of the preferred embodiment; and 
     FIG. 12 is an exploded view of parts of the bypass valve of the preferred embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention provides a renewable, spin-on type tube filter designed to remove contaminates from a lubricant or other industrial fluid. The filter media assembly advanced by the present invention is suitable for use in a wide variety of industrial applications. Referring now to FIGS. 1 and  2 , there is shown a perspective view and a cross-sectional view, respectively, of a filter according to one embodiment of the present invention and generally designated by reference numeral  10 . Filter  10  is comprised of a hollow housing  20  having a top end portion including a top member  50  and a bottom end portion. The hollow housing  20  has an interior chamber that is divided by filter media assembly element  40  into an inlet section and a discharge section. Housing  20  comprises a hollow polymeric container  60  having a bottom or closed-end  26  and an open-end  22 . Inner wall  21 , floor or bottom surface  44  and the internal surface of top member  50  define the interior chamber  42  of hollow housing  20 . 
     An external thread  28  formed about the perimeter of hollow polymeric container  60  proximate to open-end  22 . Thread  28  may be manufactured to any size which, in turn, enables filter  10  to achieve the specific pressure rating required by the particular application. Thread  28  formed to removably mate with a variety of distribution heads commonly used in industry thereby enabling filter  10  to be employed in a variety of industrial applications. 
     Hollow polymeric container  60  is made of any polymeric material that can operate in a temperature range between approximately −40° C. and 190° C. without experiencing thermal degradation. Hollow polymeric container  60  can be formed to assume any thickness and length. The dimensions of hollow polymeric container  50  are selected to provide a stable structure at its intended operating temperature and pressure. Preferably, hollow polymeric container  60  is made of a polymeric material impregnated with a quantity of glass fibers. Extending from the bottom or closed-end  26  about the perimeter of hollow polymeric container  60  is a series of serration&#39;s  30  designed to permit an individual to grasp housing  20 . Formed about the perimeter of bottom or closed-end  26  is an annular groove  32 . A circular recess  34  formed at the center of bottom or closed-end  26 . 
     Extending into the interior  42  of hollow polymeric container  60  from floor  44  is an annular shoulder  36 . Shoulder  36  is dimensioned to fit within the annular center  46  defined by filter element  40 . Shoulder  36  serves to center filter element  40  within interior  42  of hollow polymeric container  60 . As best seen in FIG. 2, the peripheral edge of top member  50  is spaced from the inner wall  21  of the hollow polymeric container  60  which defines an annular opening that functions as the industrial fluid outlet  58 . Filter element  40  may be fabricated of any filter medium commonly employed in the art including, but not limited to, stainless steel mesh, polyesters and cellulosic materials. The mesh or porosity of the filter media  40  is determined by industrial fluid and operating conditions to which they will be exposed. The stiffness of the filter must be sufficient such that it maintains its geometric integrity and will not flex or deform when exposed to normal operating conditions and/or to back flushing. Filter element  40  has an inlet surface  45  that is in fluid communication with the throughhole or industrial fluid inlet  52  and an outer or outlet surface  43  that is in fluid communication with the industrial fluid outlet  58 . If filter  40  is constructed of bendable or flexible material, a perforated annular core, made of metal or polymer, may be required so that filter element  40  maintains its geometric integrity. Filter element  40  is tubular and has an endless bottom or closed-end portion edge  47  and an endless top or open-end portion edge  41 . The filter element  40  is secured along its bottom or closed-end portion edge  47  to floor  44  by an adhesive, potting or bonding material  48 . The filter element  40  is secured along its top or open-end portion edge  41  in an annular groove  33  formed in the bottom surface of top member  50  using bonding material  48 . The annular groove  33  is located between the industrial fluid inlet  52  formed in top member  50  and the industrial fluid outlet  58  formed by the peripheral edge of top member  50  and inner wall  21  of the hollow polymeric container  60  and, thus, isolates the industrial fluid inlet  52  from the industrial fluid outlet  58 . As a consequence of this isolation, the industrial fluid that enters the inlet chamber of filter  10  through the industrial fluid inlet  52  must pass through the filter element  40  to reach the discharge section that is in fluid communication with industrial fluid outlet  58 . Bonding material  48  may be any type commonly employed in the art that will not react with the fluid being filtered and can withstand operating temperatures between approximately −40° C. and 190° C. 
     In the embodiment illustrated in FIGS. 1 and 2, top member  50  may be made of either a metal or polymer and formed to have a throughhole or industrial fluid inlet  52  in registration with annular center  46  of filter element  40 . An O-ring  54  is provided in industrial fluid inlet  52  that functions as a fluid seal between throughhole or industrial fluid inlet  52  and the distribution head. 
     Hollow polymeric container  60  can be manufactured using any process commonly employed in the art. Preferably, housing  20  is manufactured using an injection molding process. In assembling filter  10 , filter element  40  is secured to top member  50  using bonding material  48 . Bonding material  48  is then applied to floor  44  of hollow polymeric container  60 . Filter element  40  and top member  50  are then placed within interior  42  of hollow polymeric container  60  and secured to floor  44 . 
     When filter  10  requires cleaning, it is removed from the distribution head and the excess lubricant is drained. Thereafter, a cleaning solution is injected into housing  20  in the direction opposite to the direction of filtration. For example, cleaning solution may be directed through industrial fluid outlet  58  into annulus  56  which is defined by outer surface  43  of filter element  40  and the inner wall  21  of hollow polymeric container  60 . The injection of solution into annulus  56  effectuates the removal of particulates from filter element  40  and transports the fluid entrained particles into annular center  46  and subsequently from the interior  42  of hollow polymeric container  60 . Alternatively, cleaning solution may be injected through industrial fluid inlet  52  into annular center  46  to thereby cause the removal of particulates from filter element  40  through annulus  56  and industrial fluid outlet  58  to the exterior of housing  20 . An ultrasonic cleaning method could also be used for cleaning the filters  10 . After cleaning, filter  10  is dried and reused. 
     Referring now to FIGS. 3-8 another embodiment of the present invention will be discussed. FIG. 3 is a perspective view of a filter according to this embodiment of the present invention and is generally designated by reference numeral  100 . Filter  100  is comprised of a hollow housing  120  having a top-end portion, including top member  150 , and a bottom-end portion  160 . Cup-shaped bottom-end portion  160  and top member  150  are made of any polymeric material that can operate in a temperature range between approximately −40° C. and 190° C. without experiencing thermal degradation. In the preferred embodiment top member  150  and the bottom-end portion  160  are formed by an injection molding process using long fiber polymer composite reinforced thermoplastic material that is sold under the brand name CELSTRAN®. CELSTRAN® is a registered trademark of Hoechst Celanese Corporation. Cup-shaped bottom-end portion  160  can be formed to assume any thickness and length. It should be noted that, although this embodiment discloses a housing formed from a cup-shaped bottom-end portion  160  that is closed by a disc-shaped top member  150 , the top member need not be disc-shaped but rather could be a cup-shaped top member. It should also be noted that, although the hollow polymeric container or cup  160  shaped member is disclosed as being a unitary cast part, it could also be fabricated from a section of polymeric tube having a molded bottom member bonded or welded thereto. The essential feature being that the components from which the hollow housing  120  are formed are welded together to form a closed housing having an interior chamber  142  within which is securely attached the filter media assembly  140 . As best seen in FIGS. 4 and 5, which are cross-section views taken along lines  4 — 4  and  5 — 5 , respectively, of FIG. 4, housing  120  has an interior chamber that is divided into an inlet section  162  and a discharge section  164  by filter media assembly  140 . The filter media assembly  140  is securely mounted within the housing. The cup-shaped bottom-end portion has a bottom or closed-end  126  and an open or top-end  122 . Cup-shaped bottom-end portion  160  has an interior  142  that is defined by inner wall  121  and a floor or bottom surface  144 . 
     Filter media assembly  140  has a frusta-conical shape and has an endless bottom or-closed-end portion edge  147  and an endless top or open-end portion edge  141 . The illustration of the multi-layered filter media assembly  140  is shown schematically in FIG. 4 to clearly illustrate that the filter assembly is comprised of multiple layers. In this schematic rendering, the layers are shown spaced apart from each other while in reality the layers are engaged. The filter media assembly  140  is secured along its bottom or closed-end portion edge  147  in an annular groove  136  formed in floor  144  by an adhesive bonding material  148 . The filter media assembly  140  is secured along its top or open-end portion edge  141  to a filter collector member  180  which, in the preferred embodiment, is made by an injection molding process from long fiber reinforced thermoplastic material sold under the brand name CELSTRAN®. Filter collector member  180  is received in a circular groove formed in the bottom surface of top member  150 . This arrangement facilitates assembly of the filter  100  and, once assembled, the endless open-end portion edge  141  of the filter media assembly  140  is, in effect, bonded along its entire extent to the open-end top member  150 . Filter collector member  180  has a flat washer-shaped portion with at least one downward extending flange  184  along its peripheral edges. The central flange  184  forms a concentric central bore  183  that is sized to receive adapter  154 . The filter media assembly  140  is secured by an adhesive bonding material  148  along its upper closed-end portion edge  141  in the annular groove formed by the downward extending flanges  184  of collector member  180 . Filter media assembly  140  isolates the industrial fluid outlet  153  from the industrial fluid inlet  158 . As a consequence of this isolation, the industrial fluid that enters the inlet section  162  of filter  100  through the industrial fluid inlet  158  must pass through the filter media assembly  140  to reach the discharge section  164  from which it is discharged through industrial fluid outlet  153 . 
     As illustrated in FIG. 6, which is a top view of filter  100 , industrial fluid inlet  158  includes four openings  158  that are concentric with central bore  152 . The four openings  158  are separated by bridges  159 . The top member  150  includes a circular groove  157  formed in its upper or outer surface that receives a mating O-ring or other seal that functions to form a seal between the top member  150  and the distribution head (not shown). A distribution head  200  is shown in FIG.  11 . The O-ring or other seal is contained in the circular groove  157  to assure a liquid seal between the top member  150  and the distribution head. 
     As is best seen in FIG. 7, the inner wall  121  of cup-shaped bottom-end portion  160  has a recessed rim  124  formed along its upper edge that has a larger diameter than inner wall  121 . The peripheral edge  151  top member  150  has a diameter that is slightly smaller than the diameter of recessed rim  124  and, thus, the top member  150  can be lowered into the open-end of cup-shaped bottom-end portion  160  without interference. A band  125  of polymeric material having a diameter smaller than recessed rim  124  and larger than inner wall  121  is provided as a step between the bottom of recessed rim  124  and the inner wall  121 . During assembly of the filter  100 , as the top member  150  is lowered into cup-shaped bottom-end portion  160 , the bottom surface of top member  150  encounters band  125  which prevents top member  150  from becoming fully seated in cup-shaped bottom-end portion  160 . As will be discussed in more detail, this interference with band  125  will be overcome during the plastic welding process that secures the top member  150  to the cup-shaped bottom-end portion  160 . Thus, when assembly is complete, the top member  150  will be fully seated in the open-end  122  of cup-shaped bottom-end portion  160 , and member  150  and cup-shaped bottom-end portion  160  will have been bonded together as an integral member. As shall be further discussed, top member  150  is permanently secured to cup-shaped bottom-end portion  160  by a plastic weld. 
     Another embodiment for the bonding of the peripheral edge of top member  150  to the inner wall  121  of the cup-shaped bottom-end portion  160  is illustrated in FIG.  8 . In this embodiment, the peripheral edge of top member  150  has an upper section  255  that has the same diameter as the outer diameter of the cup-shaped bottom-end portion  160  and a lower section  256  that is slightly smaller than the inner diameter of the cup-shaped bottom-end portion  160 . This allows the lower section  256  of top member  150  to enter the open, upper end of the cup-shaped bottom-end portion  160  without interference. The peripheral edge of top member  150  includes a band portion  257  that has a diameter that is larger than the diameter of the lower section  256  and smaller than the diameter of the upper section  255 . As the top member  150  is lowered into the cup-shaped bottom-end portion  160 , the band portion  257  will encounter the upper edge of the cup-shaped bottom-end portion  160  and prevent the top member  150  from fully seating. At this point of the fabrication, the ultrasonic welding operation commences which melts the material forming the band portion  257  permitting the top member to completely seat in cup-shaped bottom-end portion  160  and form a bond therewith. This embodiment has the advantage that there will not be a resulting bead of weld on the upper surface of the top member  150  which could interfere with the attachment of the filter media assembly  100  to the distribution head. 
     An inner wall  121  and a floor  144  define the interior  142  of cup-shaped bottom-end portion  160 . A circular groove  136  formed in floor  144 . Groove  136 , as illustrated in FIG. 4, is located at the intersection of wall  121  and floor  144  but could be spaced centrally of this intersection. Groove  136  serves to receive the lower or bottom edge  147  of the filter media assembly  140 . Filter media assembly  140  may be fabricated of any filter medium commonly employed in the art, including but not limited to, stainless steel mesh, polyesters, or cellulose materials. Filter media assembly  140  has an outer screen  143  that is in fluid communication with the industrial fluid inlet  158  and an inner screen  145  that is in fluid communication with the industrial fluid outlet  153 . 
     The filter media assembly  140  that is illustrated in FIGS. 4 and 5 and also in FIG. 11 formed from flat material that has been cut to a shape that includes a pair of edges. This discussion of the filter media assembly  140  applies equally to the embodiment, illustrated in FIGS. 3-8, as well as the embodiment illustrated in FIGS. 9-12. When the pair of edges are joined by a weld or encapsulated by adhesive, the flat piece of material assumes the shape of a cone. In the preferred embodiment, the material is stainless steel wire mesh which provides a filter media assembly that is stiff and will not be distorted or bent by fluid flow through it. The metal mesh material is folded or pleated radially such that the filter is in the shape of a truncated cone having wave-shaped continuous top and bottom edges. The radial pleats extend from the upper peripheral edge to the lower peripheral edge of the right circular cone-shaped filter. The pleats are formed such that their amplitude becomes greater as they progress from the upper periphery edge to the lower peripheral edge. As a result of forming these pleats and joining the edges, the flat pieces of material from which filter media assembly  140  formed assumes the shape of a frustum of a right circular cone. The surface area and, thus, the filtering capacity of the filter media assembly  140  are greatly increased as a result of the pleats. Furthermore, the rigidity and therefore the geometric integrity of the filter media assembly  140  are increased considerably as a result of the pleats. The filter media assembly illustrated in FIGS. 4 and 5 is comprised of three layers of woven mesh screens. The outer screen  143  and the inner screen  145  have a wire count of 40 to 60 wires per inch. The preferred embodiment of the outer  143  and inner  145  screens have 50 stainless steel wires per inch. These relatively sturdy, woven mesh outer screens function to provide structural integrity to the filter media and also to insure pleat separation of the middle, woven mesh screen  146  to avoid the pleats from compressing upon themselves. The openings in the inner and outer, woven mesh screens are much larger than the openings of the middle, woven mesh screen  146  and as a result the middle, woven mesh screen defines the porosity of the filter media assembly. The size of the openings in the middle mesh screen  146 , for the preferred embodiment, are 25 microns. This mesh screen has a 47% porosity which means that 47% of its surface is open. Mesh screen  146  will retain particles that are larger than about 25 microns. Applicant has also used middle screens  146  that have openings of about 17 microns. The 17 micron screen has a porosity of 37%. The openings in the middle mesh screen  146  must be very small in the range of 15-30 microns. Thus, the middle layer of filter media assembly  140  functions as the filtering layer, and the inner layers  145  and outer layers  143  function to provide structural integrity and to insure pleat separation of the middle layer. 
     In the assembly process, the upper edge  141  of filter media assembly  140  is secured to the lower surface of disc-shaped filter mounting plate  180  using bonding material  148 . Bonding material  148  is then place in groove  136  formed in floor  144 . The filter media assembly with the attached disc-shaped filter mounting plate  180  is then lowered into the cup-shaped bottom-end portion  160 . The large or lower peripheral edge  147  of filter media assembly  140  approaches the groove  136  that contains bonding material  148 . The top member  150  is then lowered into the open-end  122  of the cup-shaped bottom-end portion  160  and the adapter  154  enters the central aperture  183  of the mounting plate  180 . As the top member  150  is lowered into the cup-shaped bottom-end portion  160 , the band  125  (see FIG. 7) of polymeric material engages the bottom surface of top member  150 . The top member  150  has been manufactured such that the diameter of its peripheral edge  151  is slightly smaller than the diameter of the rim  124  of the cup-shaped bottom-end portion  160 . The top member  150  and the top end  122  of the cup-shaped bottom-end portion  160  is then subjected to an ultrasonic welder which melts the band  125  of polymeric material which enables the top member  150  to be forced downwardly into place in the cup-shaped bottom-end portion  160 . The melted material of band  125  then forms a bond with the rim  124  of the inner wall  121  and the peripheral edge  138  of top member  150 . During the ultrasonic welding, the raised concentric annulus of the upper surface of filter mounting plate  180  enters the open bottom of the chamber and closes the chamber. As a result, the top member  150  has been permanently secured to the cup-shaped bottom-end portion  160  to form the housing  120 . Another result is that the bottom edge of filter media assembly  140  has been permanently secured in the groove  136  and the collector plate  180  has been joined to the top member  150  as an integral part thereof. Since the top edge of filter media assembly  140  is bonded to the collector plate  180  when assembled, the top edge of filter media assembly  140  is bonded to the top member  150 . Consequently, after assembly is completed, there can be no relative movement of filter media assembly  140  relative to the housing  120 . 
     It should be noted that, although the filter media assembly  140  that is shaped as a right circular cone is preferred, filters having other shapes, for example tubular, could be used with this invention. 
     The large or bottom peripheral edge  147  of filter media assembly  140  is secured in groove  136  formed in floor  144  by an adhesive bonding material  148 . This bonding permanently secures the lower edge  147  of the filter media assembly  140  to the cup-shaped bottom-end portion  160  such that there can be no relative movement therebetween. 
     The disc-shaped filter mounting plate  180  includes annular flanges  184  that extend downwardly from its peripheral edges. The upper peripheral edge  141  of the filter media assembly  140  is secured by epoxy bonding material  148  in the circular groove formed by flanges  184  of the disc-shaped filter mounting plate  180 . When assembled, this bonding permanently secures the upper edge of the filter  140  to the top member  150  through the filter mounting plate  180  such that there can be no relative movement therebetween. Preferably, bonding material  148  is an epoxy resin. 
     The bonding material  148  used in the preferred embodiment is a one-part epoxy resin. Two part epoxy resins must be used soon after the two parts are combined which, in a production process as used in the manufacture of these filters, would require the continuous preparation of new batches. One part epoxy resin takes longer to set and, thus, a batch can be used for longer production runs. Another advantage in this particular application of a one-part epoxy resin is, since the one-part epoxy resin takes longer to set, it has time to settle to a smooth upper surface that does not have cracks and crevasses that can trap contaminates. A one-part epoxy resin sold under the trade name ECCOBOND A-304 is available from Emerson and Cuming Specialty Polymers, a division of National Starch and Chemicals. 
     In the process of producing the parts that make up the filter  100 , cup-shaped bottom-end portion  160 , top member  150  and disc-shaped filter mounting plate  180  are manufactured using any process commonly employed in the art. Preferably, cup-shaped bottom-end portion  160 , top member  150  and disc-shaped filter mounting plate  180  are manufactured by an injection molding process using long fiber polymer composite reinforced thermoplastic materials such as CELSTRAN®. 
     Ultrasonic plastic welding is the preferred plastic welding process. An ultrasonic plastic welding apparatus has one or more sonic horns. Each sonic horn has a generator-transducer for ultrasonically activating the horn and its welding blades. When the sonic horn is activated, vibrations in the range of 20,000 cycles per second are created producing heat which melts the plastic material being welded. After deactivation of the sonic horn, a permanent welded bond formed between the top member  150  and the cup-shaped bottom-end portion  160 . This permanent bond locks the filter media assembly  140  in place within the now enclosed housing  120 . 
     When filter  100  requires cleaning, it is removed from the distribution head and the excess lubricant is drained from it. Thereafter, a cleaning solution is injected into housing  120  in the direction opposite to the direction of filtration. For example, cleaning solution is directed into outlet  153 . The injection of solution into outlet  153  effectuates the removal of particulates from filter media assembly  140  and transports the fluid entrained particles into the inlet section  162  and subsequently out fluid inlet  158 . Alternatively, cleaning solution may be injected into industrial fluid inlet  158  to thereby cause the removal of particulate from filter media assembly  140  through the outlet  153 . After cleaning, filter  100  is dried and reused. 
     Referring now to FIGS. 9 through 12, the bypass valve  250  will be discussed. The bypass valve  250  illustrated in FIGS. 9 through 12 could be incorporated into the embodiment of the filters discussed above. The same reference numbers will be used in the following discussion when referring to filter parts that are the same as those parts previously discussed with reference to the embodiment of FIGS. 3-8. 
     As best seen in FIGS. 9 and 10, top and bottom views respectfully of the top member  150 , a circular bore  152  formed therein into which is secured an internally threaded metallic adapter  154 . The internally threaded metallic adapter  154  is secured in a central circular bore  152  formed in top member  150  by bonding material  148  or by plastic welding. If it is to be secured by plastic welding, then the outer surface of threaded metallic adapter  154  is grooved or serrated to receive the liquid polymeric material during welding and, thus, lock the threaded metallic adapter  154  in place. A variety of internally threaded adapters  154  are available having internal threads that are sized to mate with a variety of distribution heads  200  commonly used in the industry, thereby enabling filter  100  to be employed in a variety of industrial applications. 
     The distribution head  200 , as best seen in FIG. 11, includes an externally threaded conduit  202  that mates with the internally threaded adapter  154 . The filtered fluid exits the filter  100  through the industrial fluid outlet  153  from which it flows into conduit  202  of the distribution head  200 . Arrow  170 , seen in FIG. 11, indicates the direction that the industrial fluid flows as it exits filter  100 . The fluid to be filtered flows from conduit  204  of distribution head  200  into filter  100  through the industrial fluid inlet  158  formed in top member  150 . 
     As best seen in FIG. 9, industrial fluid inlet  158  includes twelve openings that are concentric with central bore  152 . The twelve openings are separated by bridges  159 . As best seen in FIG. 11, top member  150  includes a circular groove  157  formed in its upper or outer surface that receives a mating O-ring  240  or other seal that functions to form a seal between the top member  150  and the distribution head  200 . The O-ring or other seal  240  is contained in the circular groove  157  to assure a liquid seal between the top member  150  and the distribution head  200 . 
     A chamber  210  formed in top member  150  which is isolated from the industrial fluid inlet  158  by wall  212  formed of the polymeric material of the top member  150 . Another wall of the chamber  210  is defined by the outer surface  155  of metal adapter  154 . The chamber  210  has openings  214  formed in the polymeric walls  212  that provide communication between chamber  210  and the industrial fluid inlet  158 . A series of openings  156  are formed through metal adapter  154  providing communication between the industrial fluid outlet  153  and chamber  210 . A spring-biased base plate  220  having a central opening  221  and an annular shoulder  222  is located within chamber  210 . Central opening  221  is sized to closely receive adapter  154  and functions as a guide for the spring-biased base plate  220 . The annular shoulder  222  extends upward around the periphery of the base plate  220  and terminates in a peripheral edge  224 . Spring-biased base plate  220  functions as the opening and closing member for bypass valve  250  and is guided during its opening and closing movement by sliding along its central opening  221  along the outer surface of metal adapter  154 . This sliding arrangement of the spring-biased base plate enables its peripheral edge  224  to always lay in a plane that is parallel to the top surface of the chamber  212  and thus insure full closure of the bypass valve  250 . When the spring-biased base plate  220  is forced up by the spring  230 , it slides along the outer surface  155  of adapter  154  and is stopped when the peripheral edge  224  engages the top surface of the chamber  210 . Peripheral edge  224  engages the top wall of chamber  210  outwardly of the openings  214  formed in the wall  212 . Between the annular shoulder  222  and the central opening  221  there is a flat annulus  223  that has a substantial area. When the spring-biased base plate  220  is in the fully raised position, it functions to effectively close the openings  214 . The fluid to be filtered that enters the filter  100  through the industrial fluid inlet  158  flows through openings  214  and exerts pressure on the flat annulus surface  223  of the spring-biased base plate  220 . When the pressure on surface  223  exceeds the upward pressure of the spring  230 , the spring-biased base plate  220  moves downwardly. As the central opening  221  in the spring-biased base plate encounters the openings  156  formed in the adapter  154 , inlet fluid flows through openings  156  into the industrial fluid outlet  153  and thus bypasses the filter media assembly  140 . Since some inlet fluid may also be flowing through filter media assembly  140 , the spring-biased base plate  220  will move down only enough to allow the bypass of sufficient fluid to maintain the inlet pressure at a predetermined acceptable level. If the pressure of the inlet fluid is sufficiently high, the spring-biased base plate  220  will continue to move downward until the openings  156  are fully open. When openings  156  are fully opened, the entire inlet oil stream can bypass the filter media assembly  140 . 
     The polymeric wall  212  forming chamber  210  includes an annular portion  226  that extends downward from the top surface of the chamber  210 . Annular portion  226  is concentric with the outer surface of said metal adapter  154  and terminates in a peripheral edge  228 . Peripheral edge  228  is located at the level of the bottom surface of top member  150 . The bottom edge of metal adapter  154  extends downward beyond the bottom surface of top member  150  and peripheral edge  228 . 
     A disc-shaped filter mounting plate  180  is provided that has an upper surface  181 , a lower surface  182  and a central aperture  183  that is sized to closely receive the outer surface of metal adapter  154 . The peripheral edge  228  of the annular portion  226  engages the upper surface  181  of disc-shaped filter mounting plate  180 . Thus, disc-shaped filter mounting plate  180  functions as the bottom surface of chamber  210 . 
     The upper surface  181  of collector member  180  has a raised concentric annulus  185  around the central bore  183  that seats in the chamber  210  formed by the polymeric walls  212  of top member  150 . The filter media assembly  140  is secured by an adhesive bonding material  148  along its bottom or closed-end portion edge  147  to annular groove  136  formed in the floor  144 . When the filter collecting member  180  is seated in chamber  210 , its lower surface  182 , defined by the downward extending flange  184  and central aperture  183 , is located between the industrial fluid outlet  153  and inlet  158  both formed in top member  150 . When filter media assembly  140  is secured in place within filter  100  it isolates the industrial fluid outlet  153  from the industrial fluid inlet  158 . As a consequence of this isolation, the industrial fluid that enters the inlet section  162  of filter  100  through the industrial fluid inlet  158  must pass through the filter media assembly  140  to reach the discharge section  164  from which it is discharged through industrial fluid outlet  153 . 
     Wave type spring member  230  is washer-shaped and has axially radiating high ridges  232  and low ridges  234  extending around its periphery. The high ridges  232  engage the bottom surface of the spring-biased base plate  220  and the low ridges  234  support the spring member  230  on the upper surface of the raised concentric annulus  185  of the filter collector member  180 . Spring  230  is generally in the form of a Belville washer, a device commonly used as a thrust element, the structure and function of which will be readily appreciated by those skilled in the art. As incorporated into the immediate invention, wave spring member  230  is sized such that, as the inlet pressure increases, it can compress which results in a slight increase in its diameter. Spring member  230  exerts a uniform pressure on the spring-biased base plate  220  over the full range of its expansion. This is important since spring-biased base plate  220  functions as the opening and closing member for the bypass valve  250 . 
     It should be understood that the foregoing disclosure is illustrative of the broad inventive concepts comprehended by this invention and that various other modifications and improvements may be made to the invention without departing from the spirit of the disclosed concept.

Technology Category: 7