Thermobondable filter medium and border frame and method of making same
AssigneeAAF-McQuay Inc.
InventorsKyung-Ju Choi, Dennis R. Porter, Paul B. Ryan
Life of this patent
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Abstract
Self-supporting pleated fluid filter medium and method of making the same wherein the filter medium and accompanying flow-through border frame are of coated thermobondable materials, which are heat bonded together.
Drawings
Claims42
) A self-supporting pleated fluid filter medium including opposed upstream and downstream faces comprising at least one sheet of thermoplastic fiber material having at least a sufficient stiffness to provide for self-supporting pleats sufficient to maintain pleat form during an anticipated fluid filtering treatment velocity, said sheet of thermoplastic material being up to one hundred (100) percent by weight of preselected thermoplastic fibers
) The self supporting pleated filter medium of claim 1, said thermoplastic material containing synthetic, chopped, blended fibers of approximately zero point three (0.3) to three (3) inch lengths with zero point five (0.5) to forty (40) denier fibers.
) The self supporting pleated filter medium of claim 1, said thermoplastic material being melt-blown fibers in a range of zero point three (0.3) to thirty-five (35) micrometers.
) The self-supporting pleated fluid filter medium of claim 1, said fibers having a Frazier permeability in the range of approximately three (3) to four thousand (4000) cubic feet per minute, per square foot (cfm/ft2).
) The self-supporting pleated fluid filter medium of claim 1, said fibers having a Gurley stiffness in the range of approximately four hundred (400) to two thousand (2000) milligrams (mg).
) The self-supporting pleated fluid filter medium of claim 2, said fibers advantageously being of an average of approximately three (3) denier fibers.
) The self-supporting pleated fluid filter medium of claim 4, said fibers advantageously having a Frazier permeability of approximately five hundred fifty (550) cubic feet per minute, per square foot (cfm/ft2).
) The self-supporting pleated fluid filter medium of claim 5, said fibers advantageously having a Gurley stiffness of approximately six hundred (600) milligrams (mg).
) The self-supporting pleated fluid filter medium of claim 1, said fibers having a Frazier permeability in the range of approximately three (3) to four thousand (4000) cubic feet per minute, per square foot (cfm/ft2) and a Gurley stiffness in the range of approximately four hundred (400) to two thousand (2000) milligrams (mg).
) The self-supporting pleated fluid filter medium of claim 9, said fibers being of low melt characteristic with an average of approximately three (3) denier fibers and with a Frazier permeability of approximately five hundred fifty (550) cubic feet per minute, per square foot (cfm/ft2) and a Gurley stiffness of approximately six hundred (600) milligrams (mg).
) The self-supporting pleated fluid filter medium of claim 1 including a facing of thermoplastic synthetic netting.
) The self-supporting pleated filter medium of claim 1, including a facing of thermoplastic non-woven scrim.
) The self-supporting pleated fluid filter medium of claim 2, including a thermoplastic non-woven synthetic binding stiffener.
) The self-supporting pleated fluid filter medium of claim 13, said synthetic binding stiffener being a polyvinyl acetate (pva) in the range by weight of fifteen (15) to sixty (60) percent (%) of the overall weight.
) The self-supporting pleated fluid filter medium of claim 13, said synthetic binding stiffener being an ethylene vinyl acetate (eva) in the range by weight of fifteen (15) to sixty (60) percent (%) of the overall weight.
) The self-supporting pleated filter medium of claim 13, said synthetic binder being acrylic material.
) The self-supporting pleated filter medium of claim 14, said synthetic binding stiffener being approximately thirty-five (35) percent (%) of the combined overall weight.
) The self-supporting pleated fluid filter medium of claim 15, said synthetic binding stiffener being approximately thirty-five (35) percent (%) of the combined overall weight.
) The self-supporting pleated fluid filter medium of claim 1, wherein said pleated filter medium is in the form of a unit filter with selected peripheral edges thereof being compressed to a flattened position.
) The self-supporting pleated filter medium of claim 19, wherein the entirety of said peripheral edges of said unit filter are compressed.
) The self-supporting pleated filter medium of claim 19, and a thermally responsive substantially stable, longitudinally extending border frame member engaging said selected compressed peripheral edges in thermally bonded relation therewith.
) The self-supporting pleated filter medium of claim 21, said border frame member comprising at least one set of thermally responsive plastic coated surface of material, said coated surface being folded to engage said selected peripheral edges therebetween in thermally bonded relation thereto.
) The self-supporting pleated filter medium of claim 21, said border frame member being of a selected coated surface cardboard material yieldable to thermal bonding pressure.
) The self-supporting pleated filter medium of claim 21, said border frame member being folded to include a longitudinally extending raised geometrically shaped portion spaced from said compressed edge of at least one of said opposed faces of said filter medium.
) The self-supporting pleated filter medium of claim 24, said longitudinally extending raised geometrically shaped portion including a flat distal end portion engaging said filter medium face.
) The self-supporting pleated filter medium of claim 21, wherein said pleated fluid filter medium is of rectangular shape and said thermally responsive border frame member is sized and conformed to engage said compressed peripheral edges thereof in thermally bonded relation therewith.
) A border frame member comprised of at least one thermally bondable flat strip of material, said strip being foldable and sized to engage opposed peripheral edge faces of fluid filter medium to be heat bonded thereto.
) The border frame member of claim 27, said strip being synthetically coated on said edge engaging face thereof to enhance heat binding.
) The border frame member of claim 27, said strip being foldable to include at least one longitudinally extending raised shape portion of triangular cross-section spaced from one of said edge faces with a flat distal end portion engaging said filter medium edge face.
) The border frame member of claim 29, wherein said shape portion of triangular cross-section slopes outwardly from the main body of said border frame member in flared fashion to accommodate stacking for storage and shipping purposes.
) A rectangularly shaped unit flow-through air filter arrangement comprising:
- a rectangularly shaped pleated fluid filter medium of layered sheets of material including at least one longitudinally extending rectangularly shaped sheet of thermoplastic synthetic fiber material of sufficient stiffness to include supported pleats sufficient to maintain pleat form during an anticipated fluid filtering treatment velocity, said at least one sheet being of up to one hundred (100) percent thermoplastic fibers of approximately three (3) denier with a Frazier permeability of five hundred fifty (550) cubic feet per minute, per square foot (cfm/ft2) and a Gurley stiffness of approximately six hundred (600) milligrams (mg);
- said rectangular synthetic fiber sheet having a compatible rectangular synthetic layer of netting facing of a compatible stiffener approximately thirty-five (35) percent by weight of the overall combined material;
- the edges of said combined fluid filter layered sheets being thermobondably compressed to be engaged by a compatibly sized flow through cardboard border member comprised of at least two thermobondably sets of similarly sized polymer coated, flat foldable strips of material folded and sized to engage and be thermally bonded to opposed peripheral edge faces of said filter medium layered sheets, each of said strips being foldable to surround and engage two opposed edge sides of the four compressed edge sides of said layered filter medium with each of said strips including a slot portion at one end thereof and a tab portion at the opposed end thereof to provide for interlocking of said strips with at least two reinforced corners, each strip further including at least one longitudinally extending raised shape portion of triangular cross-section to be spaced from said corresponding compressed edge face of said layered filter medium with a flat longitudinally extending distal end portion engaging said filter medium edge face.
) A method of assembling a selectively sized and configured pleated unit filter medium and a border frame which incorporates thermobondable materials comprising:
- heat softening selected opposed edges of at least one thermobondable unit filter medium layer, compressing said opposed selected edges of said unit filter medium into substantially flat border edges;
- mounting said unit filter medium unto a compatibly sized and configured thermobondable flow-through border frame having selected filter medium support edges to receive and support said compressed border edges of said unit filter medium in facing relationship therewith;
- and thermobonding said facing edges of said unit filter medium with said border frame.
) The method of assembling the unit filter and border frame of claim 32, wherein said heat softening of opposed select edges of said filter medium is accomplished by a heating source with within a selected temperature range.
) The method of assembling the unit filter and border frame of claim 33, wherein said temperature range is approximately one hundred fifty (150) to five hundred twenty five (525) degrees Fahrenheit (° F.).
) The method of assembling the unit filter and border frame of claim 32, wherein said thermobonding is accomplished by ultrasonic welding.
) The method of assembling the unit filter and border frame of claim 32, wherein said ultrasonic welding is at a frequency of approximately twenty (20) kilohertz (khz).
) The method of assembling the unit filter and border frame of claim 32, wherein said thermobonding comprises a preselected pattern of varied spacing.
) The method of assembling the unit filter and border frame of claim 37, wherein said thermobonding spacing is in gaps in the range of approximately zero point zero five (0.05) to zero point three (0.3) inches.
) The method of assembling the unit filter and border frame of claim 32, wherein said border frame is of selectively layered chipboard.
) The method of assembling the unit filter and border frame of claim 32, wherein said unit filter medium layer includes a thermoplastic flow-through facing and synthetic stiffener.
) The method of assembling the unit filter and border frames of claim 32, wherein said filter medium layer and border frame are of rectangular shape, said compressing of filter edges and said thermobonding of facing edges of said filter medium and said border frame being accomplished in at least two steps on a moving assembly line by pairs of spaced opposed edge compressing and thermobonding tools, one pair of which is in-line with the axis of movement of said facing edges and the other pair of which is normal to said axis of movement.
) A method of assembling a selectively sized and rectangularly configured pleated unit filter and a compatibly configured border frame which filter medium incorporates at least one layer of being up to one hundred (100) percent (%) by weight melt blown fibers of approximately sizes in the range of approximately zero point three (0.3) to thirty-five (35) micrometers and which includes a thermoplastic flow-through facing and a synthetic stiffener comprising:
- heat softening the pairs of opposed edges of said rectangular filter medium with suitable heating in the temperature range of one hundred fifty (150) to five hundred twenty-five (525) degrees Fahrenheit (° F.);
- compressing said opposed heated edges to a substantially flattened form;
- cutting said layered unit filter medium into a rectangular shape;
- mounting said rectangular unit filter medium unto a compatibly rectangularly sized selectively layered thermobondable chipboard flow-through border frame unit having inwardly extending edges to receive and support said flattened border edges of said layered unit filter medium in facing relationship therewith;
- ultrasonically welding said facing edges at a frequency of approximately twenty (20) kilohertz;
- (khz), said ultrasonic welding being accomplished on a moving assembly line with thermobonding varied spacing gaps in the range of approximately zero point zero five (0.05) to zero point three (0.3) inches, said compressing of said layered filter medium edges and said thermobonding of said facing edges being accomplished in at least two steps by respective pairs of spaced opposed edge compressing and ultrasonic thermobonding tools one pair of said ultrasonic tools being in line with the axis of movement of said facing edges and the other pair of said ultrasonic tools being normal to said axis of movement.