Pleated media filter pack, method for manufacturing a pleated media filter pack, and pleat spacing device

Abstract

The present disclosure relates to a method for manufacturing a pleated media filter media pack comprising pleat spacing structures, including: (a) providing a filtration media sheet having an inlet face and an outlet face, said filtration media sheet comprising thermoplastic fibers; (b) pleating said filtration media into a pleated media pack comprising a plurality of pleat tips including a first set of pleat tips along an upstream extent and a second set of pleat tips along a downstream extent with pleat flanks extending between the first set of pleat tips and the second set of pleat tips; and (c) applying a combination of increased pressure and increased temperature on a portion of at least a subset of said pleat tips of at least one of said first set of pleat tips and said second set of pleat tips, until said portion deforms and forms shoulder structures defining the pleat spacing structures. The present disclosure also relates to pleated media filter packs and pleat spacing device.

Description

PLEATED MEDIA FILTER PACK, METHOD FOR MANUFACTURING A PLEATED MEDIA FILTER PACK, AND PLEAT SPACING DEVICECross Reference to Related Applications

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 728,560, filed on December 5, 2024, entitled Method for Manufacturing a Pleated Filter Media Pack and Associated Pleated Filtration Media Pack, the disclosure of which is hereby incorporated by reference in its entirety. To the extent appropriate, a claim of priority is made to U.S. Provisional Application No. 63 / 728,560.Field of the disclosure

[0002] The present disclosure relates to pleated media filter packs, methods for manufacturing pleated media filter packs, and to a pleat spacing device which provides spacing between adjacent pleats in a pleated media filter pack.Background

[0003] In pleated media filter elements, the performance of the filter is enhanced or diminished by the ability of the contaminated fluid to pass freely and completely through the media. If open flow paths are maintained between the pleats (that is, the pleat faces are spaced apart), the filter normally operates at its optimum. If, on the other hand, the flow paths through the filter are in some way obstructed or reduced, e.g. when pleats bunch together, the filtering capacity of the media is diminished. Thus, maintaining a certain spacing between successive pleats in a filter element is important to the overall performance of that element.

[0004] When poor pleat spacing occurs in a filter element, not only does the pressure drop across a filter increase, but the effective area available for filtration is reduced. The net result is a reduction in the life of the filter caused by the unavailability of the entire filter media for filtration.

[0005] It is pointed out that in the context of gaseous filtration, gas flow uniformity refers to the even or uniform distribution of gas flow within a given system or environment. It signifies that the gas is being transported or distributed consistently, with minimalvariations in flow rate, velocity, or other relevant properties across the designated area or through the system. In the context of gas dynamics in filtration, achieving gas flow uniformity is helpful because non-uniform gas flow can lead to uneven pressure distribution, turbulence, or incomplete mixing, which might adversely affect the performance of the system or the desired outcome of a process. In the case of pleated media filtration or filter media, pleat crowding is characterized by pleat faces (i.e., the portion of the media extending between pleat tips) touching or even being too close to an adjacent pleat face. An increase in pleat crowding tends to result in a decrease in gas flow uniformity, and this results in increased pressure drop and also less filter media being available for filtration. Accordingly, it is desirable for adjacent pleat faces to maintain a target spacing in order to maximize filtration efficiency and useful life of a filter media pack.

[0006] Several methods for achieving pre-determined pleat spacing have been devised by others and are known in the art. These include the use of figure eight shaped pleats, the bonding of the pleat tips to a filter liner by using a bead of adhesive, and the use of string, paper or adhesive as a spacer between individual pleats. Also, various methods for corrugating or creating bumps and dimples upon the surfaces of the pleats have been employed in attempts to obtain reliable spacing between filter element pleats.

[0007] The prior art discloses methods for introducing pleat spacing for relatively thick filtration media that are costly and / or relatively complicated, resulting in relatively expensive pleated media packs.

[0008] There is a need for improved or alternative methods for introducing pleat spacing for pleated media filter packs comprising relatively thick filtration media sheets.Summary

[0009] The disclosure relates to a method for manufacturing a pleated media filter pack and to a pleated media filter pack.

[0010] In a first aspect of the present disclosure, a method is disclosed for manufacturing a pleated media filter pack comprising pleat spacing structures, the method comprising:(a) providing a filtration media sheet having an inlet face and an outlet face, the filtration media sheet comprising thermoplastic fibers;(b) pleating the filtration media into a pleated media filter pack comprising a plurality of pleat tips including a first set of pleat tips along an upstream extent and a second set of pleat tips along a downstream extent with pleat flanks extending between the first set of pleat tips and the second set of pleat tips; the pleat tips of the first set of pleat tips preferably being parallel and extending along a pleat direction being perpendicular to a first direction, the pleat tips of the second set of pleat tips preferably being parallel and extending along a pleat direction being perpendicular to a first direction, the first set of pleat tips and the second set of pleat tips preferably being parallel; and(c) applying a combination of increased pressure and increased temperature on a portion of at least a subset of the pleat tips of at least one of the first set and the second set of pleat tips, until the portion deforms and forms shoulder structures defining the pleat spacing structures.

[0011] It is pointed out that the pleat spacing structures can be referred to as integral pleat spacing structures when they are formed entirely from the filtration media sheet and without any added material. That is, the integral pleat spacing structures are formed by application of heat and pressure to portions of the pleat tips to thereby form the shoulder structures that provide pleat face separation.

[0012] It is an advantage that pleated media filter packs can be manufactured based on relatively thick filtration media sheets, and that integrated pleat spacing structures can be formed efficiently with a relatively simple process and at low cost. For instance, in certain applications, a thick layer of active carbon is required to be present in the filtration media.

[0013] According to preferred embodiments, the pleat tips of the first set of pleat tips are arranged in a single first plane and / or the pleat tips of the second set of pleat tips are arranged in a single second plane.

[0014] According to preferred embodiments, the filtration media sheet has a thickness between 0.5 and 5 mm, preferably between 0.5 and 3 mm, preferably between 1 and 3 mm.

[0015] Preferably, the filtration media sheet or filtration media pack are composite structures.

[0016] According to preferred embodiments, the filtration media sheet comprises any of or any combination of thermoplastic fibers, cellulose fibers, glass fibers and (active) carbon.

[0017] According to preferred embodiments, the filtration media comprises active carbon.

[0018] According to preferred embodiments, the filtration media further comprises a thermal bonding material, the thermal bonding material comprising any of or any combination of polyethylene terephthalate, nylon or polypropylene.

[0019] According to preferred embodiments, the filtration media sheet is a multilayer structure and comprises at least one upper sheet layer, a core layer and at least one lower sheet layer. In such embodiments, preferably, the core layer defines at least 90%, or at least 95%, or at least 98%, or at least 99% of the thickness of the filtration media sheet.

[0020] Each of the upper sheet layer, core layer and lower sheet layer can comprise a different combination of materials as defined above. For instance, each of the layers can comprise any of or any combination of thermoplastic fibers, cellulose fibers, glass fibers and (active) carbon. Each of the layers can comprise a thermal bonding material, the thermal bonding material comprising any of or any combination of polyethylene terephthalate, nylon, or polypropylene.

[0021] According to preferred embodiments, the core layer can comprise (active) carbon and polyethylene terephthalate as a thermal bonding material, while the upper and lower sheet layers comprise any of polyethylene terephthalate, nylon, polyester, or polypropylene.

[0022] According to preferred embodiments of the multilayer structure type, the core layer can comprise (active) carbon and polyethylene terephthalate as a thermal bonding material, the upper sheet layer (e.g. on the to be deformed side) comprises polypropylene and the lower sheet layer comprises polyester.

[0023] According to preferred embodiments, the upper and / or lower sheet layer (also called scrim layers) are thermoplastic and have a melting or a softening temperature which is higher than the temperature applied during the application of the combination of increased pressure and temperature on the predetermined portion.

[0024] According to preferred embodiments, the upper and / or lower sheet layer (also called scrim layers) are thermoplastic and have a melting or a softening temperature which is lower than the temperature applied during the application of the combination of increased pressure and temperature on the predetermined portion.

[0025] According to preferred embodiments, the upper and / or lower sheet layer comprise(s) a softening temperature which is higher than the softening temperature of the core layer (e.g. active carbon comprising layer).

[0026] According to preferred embodiments, the upper and / or lower sheet layer comprise(s) a softening temperature which is lower than the softening temperature of the core layer (e.g. active carbon comprising layer).

[0027] According to preferred embodiments, the locally increasing temperature comprising increasing temperature to a value of at least 150°C, preferably within the range of 150°C to 300°C, more preferably between 150°C and 250°C, more preferably between 190°C and 210°C.

[0028] The temperature can locally or generally be increased from a first, lower temperature to a second, higher temperature. The first temperature can be for instance ambient temperature, or for instance a temperature between 10°C and 40°C. The first temperature can for instance also be a temperature higher than ambient temperature and lower than the second, increased temperature (second temperature).

[0029] According to preferred embodiments, locally increasing temperature comprises or further comprises generally increasing temperature of the filtration media pack.

[0030] For instance, the whole filter media pack may be heated to a temperature within the range of 150°C to 300°C, more preferably between 150°C and 250°C, and more preferably between 190°C and 210°C.

[0031] According to alternative preferred embodiments, the temperature is generally increased (the whole filtration media sheet) to a temperature of between 80°C to 140°C,more preferably between 1OO°C and 140°C, e.g. 120°C, e.g. during a temperature step applied for pleating the filtration media sheet (corresponding to the first temperature). A further temperature increase can then be applied locally to a temperature within the range of 150°C to 300°C, more preferably between 150°C and 250°C, more preferably between 190°C and 210°C, to be applied in combination with the local application of pressure or increased pressure.

[0032] According to preferred embodiments, the locally increased pressure on the pleat tips at the end of the deformation process is at least 5 kPa, and preferably within a range starting at any of 5 kPa, 10 kPa, 20 kPa, 30 kPa, 40 kPa, 50 kPa and ending at any of 125 kPa, 150 kPa, 175 kPa or 200 kPa. More preferably, the locally increased pressure is within the range of 5 kPa to 150 kPa. More preferably, the locally increased pressure is within the range of 50 kPa to 150 kPa.

[0033] According to preferred embodiments, the average pressure on the pleat tips during the deformation process is at least 5 kPa, and preferably within a range starting at any of 5 kPa, 10 kPa, 20 kPa, 30 kPa, 40 kPa, 50 kPa and ending at any of 125 kPa, 150 kPa, 175 kPa or 200 kPa. More preferably, the locally increased pressure is within the range of 5 kPa to 150 kPa. More preferably, the locally increased pressure is within the range of 50 kPa to 150 kPa.

[0034] According to preferred embodiments, the step of applying a combination of increased pressure and temperature has a duration between 0.1 and 10 seconds.

[0035] According to preferred embodiments, the method further comprises supporting the pleated media filter sheet with a support structure.

[0036] According to preferred embodiments, the support structure is adapted and arranged for temporarily positioning and maintaining pleats of the pleated media pack at a predetermined distance.

[0037] According to preferred embodiments, the support structure further comprises local recesses such as saddle-shaped or shoulder-shaped structures, at locations where increased pressure and increased temperature is applied.

[0038] According to preferred embodiments, the method comprises, possibly additionally, heating the support structure during the local application of increased pressure and temperature.

[0039] According to preferred embodiments, the predetermined portion comprises a set of aligned sub-portions, arranged along the first direction on a set of adjacent pleat tips, and wherein the adjacent sub-portions define the pleat spacing structures which abut to one another after local deformation.

[0040] According to alternative preferred embodiments, the predetermined portion comprises a set of staggered or distributed (for instance regularly distributed) subportions on the pleat tips, and wherein the formed pleat spacing structures abut respective adjacent pleats.

[0041] According to preferred embodiments, all pleat spacing structures of the filtration media sheet are formed at the same time. Alternative, different pleat spacing structures or sets of pleat spacing structures are formed at different moments in time, for instance in separate steps. For example, each pleat spacing structure can be formed separately. According to other embodiments all pleat spacing structures on the same pleat tip are formed at the same time, and / or pleat spacing structures can be formed pleat tip by pleat tip.

[0042] According to preferred embodiments, a distance between adjacent pleat spacing structures on the same pleat tip is within the range of 2 to 10 cm.

[0043] According to preferred embodiments, locally applying a combination of increased pressure and temperature comprises pressing a pressing surface, e.g. solid surface against the local portion. Preferably the pressing surface is heated to the increased temperature at which the pleat deformation is performed.

[0044] According to alternative preferred embodiments, locally applying a combination of increased pressure and temperature comprises locally heating the material, for instance by hot air, infrared or other heating means and pressing a non-heated pressing surface (e.g. the surface itself having ambient temperature), e.g. a solid surface, against the local portion.

[0045] According to preferred embodiments, the pressing surface has a predetermined contact surface portion intended to be pressed against the pleat tips which is substantially flat or flat. Preferably, the contact surface portion comprises at least one ofa heated wheel, a heated strip, a heated bar, or a projection configured to engage an opposing recess, and the contact surface may be continuous or discontinuous.

[0046] According to preferred embodiments, the pressing surface has a predetermined contact surface portion intended to be pressed against the pleat tips which has a rounded surface. Such a rounded surface can be embodied by a wheel, a rounded rod, a ball, a cylinder surface or equivalent structures.

[0047] According to preferred embodiments, the pressing surface is made from a metal with sufficient heat conductivity such as for instance brass.

[0048] According to preferred embodiments, the method does not comprise providing or adding another type of pleat spacing structure.

[0049] According to preferred embodiments, the method further comprises cooling the pleat spacing structure immediately after formation thereof. For instance, cooling can be facilitated by a removal of a heated support structure as soon as the shoulder formation has taken place. Alternatively, or additionally, the heated support structure can be removed after the shoulder structure has been formed and another, cooled support structure can be provided instead. Alternatively, or additionally in combination with any of the previous alternatives, a cooled (e.g. solid) surface can be applied to the pleat spacer structures formed, preferably corresponding the heated surface applied during formation of the pleat spacing structures. For instance, such a cooled surface can be embodied by a wheel, a rounded rod, a ball, a cylinder surface or equivalent structures. Still alternatively, or additionally in combination with any of the previous alternatives, a cooling air flow can be provided and directed to at least the pleat spacing structure.

[0050] According to preferred embodiments, cooling the pleat spacing structure is performed while continuing the application of pressure applied during the pleat spacing structure.

[0051] According to preferred embodiments, a width of the pleat spacing structures (including portions on both sides of the respective pleat) along the first direction, i.e. along a direction perpendicular on the direction of the pleat tip, is within the range of 1 to 20 mm, more preferably within the range of 5 to 20 mm.

[0052] According to preferred embodiments, a length of a pleat spacing structure along the pleat direction is within the range of 1 to 20 mm, preferably 1 to 10 mm.

[0053] According to preferred embodiments, a deformation depth of a pleat spacing structure in a direction perpendicular to a plane defined by the first direction and the pleat direction is within the range of 1 to 10 mm, more preferably within the range of 1 to 5 mm.

[0054] For instance, if the support structure does not allow the lower surface of the predetermined portion to deform downwardly (along the symmetry axis of the respective pleat), the predetermined portion may be compressed (resulting in a local thickness reduction) and extend laterally from the respective pleat to form the pleat spacing structure. Instead, if the support structure allows the lower surface to deform (for instance in case the support structure comprises local recesses such as for instance saddle- shaped or shoulder-shaped structures, at locations where increased pressure and increased temperature is applied), a limited thickness reduction of the predetermined portion can be expected. The latter option is expected to provide slightly better performance and provides the advantage that it reduces the risk of crushing fragile materials in the filter media during local deformation, such as for instance (active) carbon particles.

[0055] In a second aspect of the present disclosure, a pleated media filter pack is disclosed comprising a pleated media filter sheet comprising a plurality of pleat tips including a first set of pleat tips along an upstream extent and a second set of pleat tips along a downstream extent with pleat flanks extending between the first set of pleat tips and the second set of pleat tips; the pleat tips of the first set of pleat tips preferably being parallel and extending along a pleat direction being perpendicular to a first direction, the pleat tips of the second set of pleat tips preferably being parallel and extending along a pleat direction being perpendicular to a first direction, the first set of pleat tips and the second set of pleat tips preferably being parallel; the pleated media filter sheet comprising filtration media that comprises thermoplastic fibers and the pleated media filter pack comprising integrated pleat spacing structures.

[0056] According to preferred embodiments, the pleat tips of the first set of pleat tips are arranged in a single first plane and / or the pleat tips of the second set of pleat tips are arranged in a single second plane.

[0057] According to preferred embodiments, the filtration media sheet has a thickness between 0.5 mm (or 1 mm or 2 mm) and 5 mm, preferably between 0.5 (or 1mm or 2 mm) and 3 mm, and preferably between 1 and 3 mm.

[0058] According to preferred embodiments, the filtration media sheet comprises any of or any combination of thermoplastic fibers, cellulose fibers, glass fibers and (active) carbon.

[0059] According to preferred embodiments, the filtration media comprises active carbon.

[0060] According to preferred embodiments, the filtration media further comprises a thermal bonding material, the thermal bonding material comprising any of or any combination of polyethylene terephthalate, nylon or polypropylene.

[0061] According to preferred embodiments, the filtration media sheet is a multilayer structure and comprises at least one upper sheet layer, a core layer and at least one lower sheet layer. In such embodiments, preferably, the core layer defines at least 90%, or at least 95%, or at least 98%, or at least 99% of the thickness of the filtration media sheet.

[0062] Each of the upper sheet layer, core layer and lower sheet layer can comprise a different combination of materials as defined above. For instance, each of the layers can comprise any of or any combination of thermoplastic fibers, cellulose fibers, glass fibers and (active) carbon. Each of the layers can comprise a thermal bonding material, the thermal bonding material comprising any of or any combination of polyethylene terephthalate, nylon or polypropylene.

[0063] According to preferred embodiments, the core layer can comprise (active) carbon and polyethylene terephthalate as a thermal bonding material, while the upper and lower sheet layers comprise any of polyethylene terephthalate, nylon, polyester or polypropylene.

[0064] According to preferred embodiments of the multilayer structure type, the core layer can comprise (active) carbon and polyethylene terephthalate as a thermal bonding material, the upper sheet layer (e.g. on the to be deformed side) comprises polypropylene and the lower sheet layer comprises polyester.

[0065] According to preferred embodiments, at least one of the upper and lower sheet layer is thermoplastic and has a melting temperature, or a minimal melting temperature of its constituting components, which is higher than a melting temperature, or a minimal melting temperature of the constituting components, of the core layer.

[0066] According to preferred embodiments, at least one of the upper and lower sheet layer is thermoplastic and has a melting temperature, or a minimal melting temperature of its constituting components, which is lower than a melting temperature, or a minimal melting temperature of the constituting components, of the core layer.

[0067] According to preferred embodiments, the upper and / or lower sheet layer comprise(s) a softening temperature which is higher than the softening temperature of the core layer (e.g. active carbon comprising layer).

[0068] According to preferred embodiments, the upper and / or lower sheet layer comprise(s) a softening temperature which is lower than the softening temperature of the core layer (e.g. active carbon comprising layer).

[0069] According to preferred embodiments, the predetermined portion comprises a set of aligned sub-portions, arranged along the first direction on a set of adjacent pleat tips, and wherein the adjacent sub-portions define the pleat spacing structures which abut to one another after local deformation.

[0070] According to alternative preferred embodiments, the predetermined portion comprises a set of staggered sub-portions on the pleat tips, and wherein the formed pleat spacing structures abut respective adjacent pleats.

[0071] According to preferred embodiments, a distance between adjacent pleat spacing structures on the same pleat is within the range of 2 to 10 cm.

[0072] According to preferred embodiments, the pleated media filter pack does not comprise another type of pleat spacing structures.

[0073] According to preferred embodiments, a width of the pleat spacing structures along the first direction is within the range of 1 to 20 mm, more preferably between 5 and 20 mm.

[0074] According to preferred embodiments, a length of a pleat spacing structure along the pleat direction is within the range of 1 to 20 mm, preferably 1 to 10 mm.

[0075] According to preferred embodiments, a deformation depth of a pleat spacing structure in a direction perpendicular to a plane defined by the first direction and the pleat direction is within the range of 1 to 10 mm.

[0076] According to another preferred embodiment, a pleat spacing device is provided that includes: a pleated media station configured to receive a pleated media pack; and a heated surface configured to move relative to the pleated media pack located in the pleated media station to cause formation of pleat spacing structure in pleat tips of the pleated media pack, and wherein the pleat spacing device is configured to provide the heated surface at a pressure of at least 5 kPa and a temperature of at least 150°C for a duration of 0.1 to 10 seconds to the pleat tips to cause the formation of the pleat spacing structures. The heated surface may include at least one wheel, at least one heated strip, at least one heated bar, or at least one projection configured to engage an opposing recess. The heated surface may include at least one wheel and wherein the heated surface is continuous. The heated surface may include at least one wheel and wherein the heated surface is discontinuous. The heated surface may be provided at a temperature of at least 150°C, preferably within a range of 150°C to 300°C, more preferably between 150°C and 250°C, and more preferably between 190°C and 210°C. The heated surface may provide the pressure of at least 5 kPa, preferably within a range of 5 kPa to 200 kPa, 10 kPa to 175 kPa, or 50 kPa to 150 kPa. According to preferred embodiments, the step of applying a combination of increased pressure and temperature has a duration between 0.1 and 10 seconds to form the pleat spacing structure to form the pleat spacing structure.

[0077] Another alternative embodiment of a pleat spacing device relates to a knife pleater construction, and another embodiment of a method of forming pleat spacing structures in pleated filter media includes utilizing a knife pleater construction. The knife pleater construction can provide, and the method can include providing, a heated surface on the pleated media pack at a temperature of at least 150°C, preferably within a range of 150°C to 300°C, more preferably between 150°C and 250°C, and more preferably between 190°C and 210°C, and the construction may provide the heated surface with a pressure of at least 5 kPa, preferably within a range of 5 kPa to 200 kPa, 10 kPa to 175 kPa, or 50 kPa to 150 kPa in order to form the pleat spacing structures. According topreferred embodiments, the step of applying a combination of increased pressure and temperature has a duration between 0.1 and 10 seconds to form the pleat spacing structure.

[0078] A further alternative embodiment of a pleat spacing device relates to a hot air media deforming construction, and another embodiment of a method of forming pleat spacing structures in pleated filter media includes utilizing a hot air media deforming construction. The hot air media deforming construction can provide, and the method can include providing, a heated surface on the pleated media pack at a temperature of at least 150°C, and preferably within a range of 150°C to 300°C, more preferably between 150°C and 250°C, and more preferably between 190°C and 210°C, and the air pressure may provide the heated surface with a pressure of at least 5 kPa, and preferably within a range of 5 kPa to 200 kPa, 10 kPa to 175 kPa, or 50 kPa to 150 kPa in order to form the pleat spacing structures. According to preferred embodiments, the step of applying a combination of increased pressure and temperature has a duration between 0.1 and 10 seconds to form the pleat spacing structure.

[0079] Features and advantages disclosed for one of the above aspects of the present disclosure are hereby also implicitly disclosed for the other aspects, mutatis mutandis, as the skilled person will recognize. For instance, features disclosed for the method are considered to be also disclosed for the pleated media filter pack.Brief Description of the Drawings

[0080] These and further aspects of the present disclosure will be explained in greater detail by way of example and with reference to the accompanying drawings which are summarized.

[0081] Figures 1(a) to (d) illustrate a method for manufacturing a pleated media filter pack according to preferred embodiments of the present disclosure.

[0082] Figure 2 illustrates a pleated media filter pack manufactured by the method illustrated in Figures 1 (a) to (d).

[0083] Figure 3 is a top view of a portion of a pleated media filter pack as manufactured according to the disclosed method.

[0084] Figures 4(a) and (b) are perspective views of a portion of the filter media filter pack of Figure 3.

[0085] Figure 5 illustrates characterizing parameters of a pleated media filter pack according to the present disclosure.

[0086] Figures 6(a) to (d) illustrate a similar embodiment as illustrated in relation to Figure 2. Figure 6(a) is a perspective view, Figure 6(b) is a side view parallel to the pleat direction, Figure 6(c) is a top view, and Figure 6(d) is a side view perpendicular to the pleat direction.

[0087] Figures 7(a) and (b) are a side view and a perspective view of a tubular pleated media filter pack illustrated in Figures 6(a) to (d).

[0088] Figures 8(a) to (d) illustrate a similar embodiment as illustrated in relation to Figures 6(a) to (d), but with staggered pleat spacing structures. Figure 8(a) is a perspective view, Figure 8(b) is a side view parallel to the pleat direction, Figure 8(c) is a top view, and Figure 8(d) a side view perpendicular to the pleat direction.

[0089] Figures 9(a) to (d) illustrate side views of exemplary heated wheels used in the method for manufacturing a pleated media filter pack according to preferred embodiments of the present disclosure.

[0090] Figures 10(a) to (c) illustrate exemplary profiles of heated wheels used in the method for manufacturing a pleated media filter pack according to the preferred embodiments of the present disclosure.

[0091] Figures 11 (a) to (b) illustrate heated strips and bars as alternatives to the heated wheels used for manufacturing a pleated media filter pack according to the present disclosure.

[0092] Figures 12(a)-(c) illustrate a knife pleater construction and a method of forming pleat spacing structures in pleated filter media according to an embodiment of the disclosure.

[0093] Figures 12(a)-(b) illustrate a hot air media deforming construction and method of forming pleat spacing structures in pleated filter media according to an embodiment of the disclosure.

[0094] The drawings of the figures are neither drawn to scale nor proportioned.Generally, identical components are denoted by the same reference numerals in the figures.Detailed Description

[0095] The present disclosure will be described in terms of specific embodiments, which are illustrative of the disclosure and not to be construed as limiting. It will be appreciated by persons skilled in the art that the present disclosure is not limited by what has been particularly shown and / or described and that alternatives or modified embodiments could be developed in the light of the overall teaching of this disclosure. The drawings described are schematic and are non-limiting.

[0096] Use of the verb “to comprise,” as well as the respective conjugations, does not exclude the presence of elements other than those stated. Use of the article “a,” “an,” or “the” preceding an element does not exclude the presence of a plurality of such elements.

[0097] Furthermore, the terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the disclosure described herein are capable of operation in other sequences than described or illustrated herein.

[0098] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiments is included in one or more embodiments of the present disclosure. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may refer to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitablemanner, as would be apparent to one ordinary skill in the art from this disclosure, in one or more embodiments.

[0099] Figures 1 (a) to (d) illustrate a preferred embodiment of the present disclosure in a schematic manner. A method is disclosed for manufacturing a pleated media filter pack comprising pleat spacing structures. It is pointed out that the pleat spacing structures can be referred to as integral pleat spacing structures when they are formed entirely from the filtration media sheet and without any added material. That is, the integral pleat spacing structures are formed by application of heat and pressure to portions of the pleat tips to thereby form the shoulder structures that provide pleat face separation.

[0100] First, a filtration media sheet 2 is provided having an inlet face 2a and an opposite outlet face 2b. The filtration media sheet comprises thermoplastic fibers. The filtration media sheet 2 is pleated and formed into a pleated media pack 1 comprising a plurality of pleat tips 20 including a first set of pleat tips 21 along an upstream extent and a second set of pleat tips 21* along a downstream extent with pleat flanks 23 extending between the first set of pleat tips 21 and the second set of pleat tips 21*. The pleat flanks23 can be referred to as pleat faces. The first set and the second set of pleat tips 21 , 21* extend in a parallel manner and along a pleat direction which is perpendicular to a first direction X (Fig. 1 a). The pleating of the filtration media sheet 2 is performed at a first temperature, for example, at ambient temperature.

[0101] Then, locally a combination of increased pressure and increased temperature, for example, a pressure of about 90kPa and a temperature of about 190°C is applied on a predetermined portion of at least a subset of the pleat tips of the first set of pleat tips 21. The term “locally” implies that the application is applied at a subset location compared to the media pack as a whole. In this case, the application is to a relatively small area along a pleat tip of the first set of pleat tips 21 . The application can be, for example, by pressing a heated wheel or heated rod structure or other heated object 3 against the predetermined portion as illustrated, for example, in Figure 1 (b) until the predetermined portion locally deforms, due to partial and local melting of, or deformation of, the thermoplastic fibers and / or thermal bonding of material in the filtration media sheet, and forms pleat spacing structures 22, that can include shoulder structures24 that provide the spacing between adjacent pleat faces, as illustrated in Figure 1 (c). The pleated media filter pack 1 can then be used in a panel filter arrangement 12 as illustrated in Figure 1 (c) or a tubular filter arrangement 10 as illustrated in Figure 1 (d). The tubular filter arrangement 10 can be referred to as a coiled or wound filterarrangement and can be provided as a cylindrical filter arrangement or as a conical filter arrangement. In general, a tubular filter arrangement includes an open interior around which is located filter media. Typically, end caps are provided at each end, and one of the end caps includes an opening therethrough and the other end cap is closed. In some cases, both end caps can have an opening therethrough. For example, it may be desirable for one end cap to have an opening for flow of gas therethrough, and the other end cap may be open to flow of water therethrough for exiting the media pack.

[0102] Fig. 2 illustrates a filtration media pack 1 in a panel filter arrangement 12 and manufactured by the method illustrated in Figures 1 (a)-(c). The pleat spacing structures 22 comprise an inwardly oriented curved surfaces (convex) and extend laterally (along direction X), and preferably, from both sides of the respective pleat tip 21 , separating adjacent pleat faces and allowing the filtration media pack 1 to maintain the separation of the pleat faces during use. In addition, the pleat spacing structures 22 can provide separation between the remaining, non-deformed, parts of the respective adjacent pleat tip 21 from the directly adjacent pleat tips 21 . It should be understood that the term “adjacent” is meant to refer to the closest pleat face and / or pleat tip and does not require physical touching. The inwardly curved surface extends downwards for about a few mm from the pleat tip 21 into the respective pleat. Laterally (along direction X) the formed pleat spacing structures 22 extend for at least a few mm from each side of the respective pleat tip 21 .

[0103] Figures 3 and Fig. 4 (a) and (b) are images of a portion of a sample of a filtration media pack 1 manufactured using a method of the present disclosure. It can be clearly seen that the pleat tips 21 , which are relatively thick, are separated and can remain separated during use due to the introduced pleat spacing structures 22 that can include shoulder structures 24. It was moreover found that introducing the disclosed pleat spacing structures 22 do not substantially impact the filter performance when compared to the ideal case wherein adjacent pleats do not bunch together during use and no pleat spacing structures are present.

[0104] The samples depicted in Figure 3 and Figures 4(a) and (b) are manufactured according to the following process. A filtration media sheet 2 is provided having an inlet face and an outlet face, the filtration media sheet comprising thermoplastic fibers. The filtration media sheet 2 is a multilayer structure comprising a core layer and relatively thin upper and lower scrim layers, having a total thickness of about 2.5 mm. The core layer comprises active carbon and polyethylene terephthalateas a thermal bonding material. The upper sheet layer (on the to be deformed side) comprises polypropylene and the lower sheet layer comprises polyester. The filtration media sheet 2 is pleated, resulting in a pleated media pack 1 having constant total pleat height of 39 mm. The first set of pleat tips 21 are spaced at a distance of about 1 mm, and are supported on one side of the media pack 1 by a pleat support structure comprising metal plates or knifes 4 which were about 32 mm high (measured along the symmetry plane of the pleats, and up until a bottom plate; see below) and about 1.5mm thick. The metal plates 4 are arranged in a parallel fashion supporting all of the pleats of the first set of pleat tips 21 (Fig. 4 (b)) and protrude from a flat bottom plate (not depicted), the latter supporting the second set of pleat tips 21* which are not shown in Figures 3 and 4(a) and (b). The second set of pleat tips 21* thereby preferably rest on the flat bottom plate. In this case, the distance between the upper edge of the metal plates of knives 4 and the (inner surface of the) pleat tips 21 of the first set of pleat tips is about 4.5 mm. A metal (brass) rod having a flat pressing surface was heated to a temperature of about 200°C and was pressed with the pressing surface against the predetermined portion of the first set of pleat tips 21 under controlled average pressure of about 88.6 kPa (N / m2), in order to locally deform the predetermined portions of the pleat tips 21 and manufacture the pleat spacing structures 22 and shoulders 24. Thereby, the lower surface of the predetermined portion of the first set of pleat tips 21 is limited in its downward vertical deformation by the distal end of the pleat support plates 4. Adjacent pleat spacing structures 22 are thereby deformed such that they abut or touch each other in the finally deformed state. This process can be performed in a room at ambient or room temperature of about 21 °C.

[0105] Figure 5 illustrates characterizing parameters of a filtration media pack 1 according to the present disclosure. The width (d3) of the pleat spacing structures 22 along the first direction X, which is perpendicular to the pleat direction, is preferably within the range of 1 to 20 mm, alternatively 1 to 10 mm. The length (d1) of the pleat spacing structures 22 along the pleat direction is preferably within the range of 1 to 20 mm, alternatively 1-10 mm. A distance (d2) between adjacent pleat spacing structures 22 on the same pleat tip 21 is preferably within the range of 2 to 10 cm. A deformation depth (d4) (see also Figure 6(d)) of a pleat spacing structure 22 in a direction perpendicular to a plane defined by the first direction and the pleat direction is preferably within the range of 1 to 10 mm.

[0106] Figures 6(a) to (d) illustrate a similar embodiment as illustrated in relation to Figure 2. Figure 6(a) is a perspective view, Figure 6(b) a side view parallel to the pleat direction, Figure 6(c) is a top view, and Figure 6(d) is a side view perpendicular to the pleat direction. The predetermined portion includes three sets of aligned sub-portions, each set arranged along the first direction X on a set of adjacent pleat tips, and wherein the three sets of aligned sub-portions define the pleat spacing structures 22 which abut to one another after local deformation.

[0107] Figure 7(a) and (b) are a side view and a perspective view of the tubular filter media pack 10 formed from the filter media pack 1 illustrated in Figures 6(a) to (d), and which is manufactured by rolling or coiling the filter media pack 1 and connecting respective filter media pack ends as is known in the art. The pleat spacing structures 22 thereby form a plurality of (e.g. three) continuous bands on the outer surface of the tubular filter media pack, each of the bands arranged and extending in a plane perpendicular to the longitudinal axis of the tubular filter media pack 10.

[0108] Figures 8(a) to (d) illustrate a similar embodiment as illustrated in relation to Figures 6(a) to (d) but with staggered pleat spacing structures 22. Figure 8(a) is a perspective view, Figure 8(b) is a side view parallel to the pleat direction, Figure 8(c) is a top view, and Figure 8(d) is a side view perpendicular to the pleat direction. As illustrated, the spacing structures 22 of adjacent pleat tips 21 are offset with respect to each other, such that local pleat spacing is a result of a pleat spacing structure 22 abutting an adjacent pleat flank of an adjacent pleat.

[0109] In the context of Figure 1 (b), the pleat spacing structures 22 are formed by application of the heated wheel 3 to the first set of pleat tips 21 . As illustrated, the heated wheel 3 is caused to roll over the first set of pleat tips 21 to form the pleat spacing structures 22. It should be noted that the movement between the heated wheel 3 and the first set of pleat tips 21 is relative. That is, the heated wheel 3 can move relative to a stationary media pack 1 , the media pack 1 can move relative to a stationary heated wheel 3, or the media pack 1 and the heated wheel 3 can both move. Furthermore, although reference is made to a heated wheel, it should be appreciated that the structure need not be a wheel and may be a heated structure such as a heated strip and / or a heated bar that glides or slides across the media pack as explained in more detail, but the same principles regarding relative movement between the heated structure and the media pack applies.

[0110] The heated structure can take the form of a heated wheel 30 as shown in Figure 9(a) which is a side view depiction of the heated wheel 3 in Figure 1 (b). The heated wheel 30 includes a continuous surface 31 that depresses a portion of all the first set of pleat tips 21 across the media pack 1 unless it is separated from the media pack 1 which is an alternative. That is, the heated wheel 30 can be configured so that the surface 31 depresses one or more pleat tips 21 and then disengages from one or more pleat tips 21 and then engages one or more pleat tips 21 , etc. Now referring to Figures 9(b)-(d), heated wheels 34, 36, and 38 are provided with a discontinuous or noncontinuous surface 40, 42, and 44. In the case of the heated wheels 34 and 36, the discontinuity is symmetric which means that the heated wheels 34 and 36 are configured to depress and not depress an equal number of pleat tips as they rotate. For example, heated wheel 34 includes alternating depressing surface 35 and recessed surface 35’ so that every other pleat is depressed. Heated wheel 36 includes alternating depressing surface 37 and recessed surface 37’ that each depress or do not depress and equal number of pleat tips. For example, an exemplary pattern may be depressing two pleat tips and then not depressing two pleat tips, and then repeating the same pattern. Of course, the number for establishing the desired pattern can be any desired number. For the heated wheel 38, the resulting number of depressed pleat tips and nondepressed pleat tips can be different. As illustrated the heated wheel 38 includes alternating depressing surface 39 and recessed surface 39’. For example, the heated wheel 38 may depress three pleat tips, and then not depress two pleat tips, and then repeat the pattern. In addition, the heated wheels 34, 36, and 38 can be referred to as geared or toothed or serrated wheels. Also, in a manner similar to heated wheel 30, the heated wheels 34, 36, and 38 can be configured so that engage the media and disengage the media as a result of, for example, being lifted away from the media. It is also pointed out that multiple sets of heated wheels can be provided to create different patterns of pleat spacing structures 22 across the first set of pleat tips 21. For example, a comparison of Figures 6(a) and 8(a) illustrate the potential use of one set of heated wheels to provide the pattern of Figure 6(a) and two sets of heated wheels to provide the pattern of Figure 8(a), although it should also be appreciated that one set of heated wheels, with the appropriate toothing configuration, can be used to provide the pattern of Figure 8(a).

[0111] Now referring to Figures 10(a)-(c), the heated wheel can be provided with alternative profiles that provide the desired resulting pleat spacing structures 22 and shoulder structures 24. Figure 10(a) includes a tapered profile 50 having a flatengagement surface 52 and tapered sides 54, Figure 10(b) includes a rounded profile 60 having a curved engagement surface 62, and figure 10(c) includes a flat engagement profile 70 having a flat surface 72 without a taper therefrom. It is noted that the curved surface 62 can be concave or convex depending the desired resulting shape of the pleat spacing structures. Also, the various shapes can be used in combination. For example, an exemplary profile can be a combination of a curve (concave or convex) and tapered sides. Another variable that can be adjusted includes, for example, the width of the surface contacting the pleat tips. It should also be appreciated that these exemplary profiles can be applied to the exemplary wheels depicted in Figures 9(a)-(d).

[0112] Now referring to Figures 1 1 (a) and (b), exemplary heated strip 80 and heated bar 82 are depicted and can be used in place of or in combination with the heated wheels. In the case of the heated strip 80, the heated strip 80 can move relative to the media pack to deform the pleat tips of the media pack, and in the case of the heated bar 82, the heated bar 82 can also move relative to the media pack to deform the pleat tips. The heated bar 82 includes a first part 84 that gradually engages the pleat tips as it moves relative to the media pack. It should also be appreciated that the exemplary profiles depicted in Figures 10(a)-(c) can be applied to the exemplary strip 80 and bar 82 depicted in Figures 1 1 (a)-(b). In addition, the strip 80 and bar 82 can be provided with a profile that changes along its length to provide the desired pleat spacing structures 22 in the resulting media pack. In general, the heated strip 80 and the heated bar 82 are configured to apply heat the pressure to multiple pleat tips at the same time. By multiple, it is meant at least two and preferably at least three.

[0113] It should be appreciated that the heated wheels depicted in Figures 9(a)- (d) and the heated strip or bar depicted in Figures 1 1 (a)-(b) can be used in a multiple arrangement across the media pack. Figure 1 (b) illustrates three heated wheels 3 located across the media pack 1 to provide essentially three lines of pleat spacing structures 22. Similarly, the heated wheels in Figure 9(a)-(c) and the heated strip and heated bar in Figures 11 (a)-(b) can be used in multiple arrangements for providing desired pleat spacing structures 22 to a formed tubular media pack.

[0114] It is also noted that aids may be used to facilitate the formation of the pleat spacing structures 22. For example, chemicals that provide a reduction in glass transition temperature, or softening of the fiber, can be applied to help in the formationof the pleat spacing structures 22. For example, water, steam, heat, and chemicals such as plasticizers, can be applied. Various techniques for application include misting, spraying, wetting, and dipping.

[0115] Figures 12(a)-(c) illustrate an alternative embodiment of the present disclosure of a method and apparatus for manufacturing a pleated media filter pack comprising pleat spacing structures. This alternative embodiment can be referred to a a pleat spacing device, and includes a knife pleater construction 100 and includes using knife pleater construction 100 to provide pleat spacing structures in a pleated media pack. The knife pleater construction 100 includes a first knife 102 and an opposite second knife 104. The first knife 102 and the second knife 104 can create pleats in a sheet of filter media 120 by folding the sheet of filter media 120 into a pleated construction 122 having alternating pleat faces 124 extending between a first set of pleat tips 126 and a second set of pleat tips 128. It should be appreciated, however, that the first knife 102 and the second knife 104 need not form the pleats on the pleated media pack. That is, the pleated media pack can arrive between the first knife 102 and the second knife 104 in a configuration where the pleats are already formed. The knife pleater 100 includes, on the first knife 102, a projection structure 106 having a pleat deformation surface 107, and on the second knife 104, a recess structure 108 having a pleat deformation surface 109 configured to receive the projection structure 106. Alternatively, the first knife 102 can include the recess structure, and the second knife 104 can include the projection structure. In a preferred embodiment, the projection structure 106 is heated and the recess structure 108 is not heated. Of course, that can be reversed, and the projection structure can be unheated and the recess structure can be heated. Furthermore, both the projection structure and the recess structure can be heated. The amount of heating can be selected is to provide the temperature range identified above in the context of the heated wheel for deforming the pleat tips to provide the pleat spacing structure.

[0116] As illustrated, the projection structure 106 is located along a side 11 1 of the first knife 102 and spaced from the tip 1 12 of the first knife 102 so that the projection structure 106 engages the recess structure 108 located on the second knife 104 and being recessed from the tip 1 13 of the second knife 104. When forming pleated media from a sheet of filter media 120, the tip 112 of the first knife 102 forms the second set of pleat tips 128, and the tip 113 of the second knife 104 forms the first set of pleat tips 126.As illustrated, the pleat spacing structures are formed in the first set of pleat tip 126 as a result of being deformed between the projection structure 106 and recess structure 108. Of course, alternatives are possible. That is, the pleat spacing structures can be formed in the pleat tips 128 or in both the pleat tips 126 and the pleat tips 128. In addition, it should be appreciated that the knife pleater can include a plurality of the knives.

[0117] Now referring to Figures 13(a) and (b), an alternative embodiment of the present disclosure can be referred to as a pleat spacing structure and includes depressing the pleat tips against a recess in a blade, similar to the recess structure 108, except that instead of using a projection structure 106, a stream of heated air is used to both heat the filter media at the intended location of the pleat spacing structure and also apply sufficient pressure to deform the filter media into the recess structure. As illustrated, a knife wheel 140 is provided with a plurality of knives 142 having tip structures 144 for supporting the pleated media 150 along the first set of pleat tips 152. Recesses 153 can be located in the tip structures 144 and provides recesses in the tip structures 144 at locations where it is desired to place the pleat spacing structures in the pleated media. The recesses 153 can be similar to the recess structure 108. A stream of hot air 154 from, for example, an air gun, can be directed against pleated media at the location of a recess 153 in order to deform the media at the location of the recess 153 to form the pleat spacing structures. The media 150 can travel in the direction of the arrow 160 as a result of the rotation of the knife wheel 140 in the direction of the arrow 162.

[0118] While in the examples described above the pleat tips of the first set of pleats are arranged in a single first plane and are parallel, the pleat tips of the second set of pleats are arranged in a second plane and are parallel, and the first set of pleat tips is parallel with the second set of pleats tips, these features are not mandatory in all embodiments. For instance, only the first set of pleat tips, which is to be locally deformed, may be arranged in a single first plane, while the second set of pleat tips may not. For instance, the pleats of the first set of pleat tips (to be locally deformed) may also be arranged in a single plane but may not be parallel. Or, for instance, the first set of pleat tips (to be locally deformed) may not be arranged in a single plane, but for instance along a curved surface, while preferably being parallel. Associated suitable support structures may have to be provided in such cases, arranged and adapted for supporting at least the first set of pleat tips and preferably also the second set of pleat tips.

[0119] Also, a corresponding pressing surface may have to be used. For instance, in case the first set of pleat tips (to be locally deformed) are arranged along acurved surface (and are preferably parallel), a corresponding curved pressing surface may be used to locally deform the pleat tips.

Claims

Claims1 . A method for manufacturing a pleated media filter pack comprising pleat spacing structures, comprising: a) providing a filtration media sheet having an inlet face and an outlet face, said filtration media sheet comprising thermoplastic fibers; b) pleating said filtration media into a pleated media pack comprising a plurality of pleat tips including a first set of pleat tips along an upstream extent and a second set of pleat tips along a downstream extent with pleat flanks extending between the first set of pleat tips and the second set of pleat tips; and c) applying a combination of increased pressure and increased temperature on a portion of at least a subset of said pleat tips of at least one of said first set of pleat tips and said second set of pleat tips, until said portion deforms and forms shoulder structures defining said pleat spacing structures.

2. A method according to claim 1 , wherein said filtration media sheet has a thickness between 0.5 and 5 mm.

3. A method according to any of the previous claims, wherein said filtration media sheet comprises any of or any combination of thermoplastic fibers, cellulose fibers, glass fibers, or active carbon.

4. A method according to claim 3, wherein said filtration media comprises active carbon.

5. A method according to any of the previous claims, wherein said filtration media sheet further comprises a thermal bonding material, said thermal bonding material comprising any of or any combination of polyethylene terephthalate, nylon, or polypropylene.

6. A method according to any of claims 1 to 5, wherein said filtration media sheet is a multilayer structure and comprises at least one upper sheet layer, a core layer, and at least one lower sheet layer.

7. A method according to claim 6, wherein said upper and lower sheet layers are thermoplastic and have a melting temperature which is higher than a temperatureapplied during said applying a combination of increased pressure and temperature on said portion of said pleat tips.

8. A method according to any of the previous claims, wherein said increased temperature comprising a temperature within a range of 150°C to 300°C, more preferably within a range of 150°C and 250°C, more preferably within a range of 190°C and 210°C.

9. A method according to any of the previous claims, wherein said locally increasing temperature comprises or further comprises generally increasing temperature of said filtration media pack.

10. A method according to any of the previous claims, wherein said increased pressure is within a range of 5 to 200kPa.

11. A method according to any of the previous claims, wherein the step of applying a combination of increased pressure and increased temperature has a duration of 0.1 to 10 seconds.

12. A method according to any of the previous claims, further comprising supporting said pleated media filter sheet with a support structure.

13. A method according to claim 12, wherein said support structure is adapted and arranged for temporarily positioning and maintaining pleats of said pleated media pack at a predetermined distance.

14. A method according to claims 12 or 13, wherein said support structure further comprises recesses, such as, for instance, saddle-shaped or shoulder-shaped structures, at locations where increased pressure and increased temperature is applied.

15. A method according to any of claims 12 to 14, comprising additionally heating said support structure during said application of increased pressure and increased temperature.

16. A method according to any of the previous claims, further comprising cooling said pleat spacing structure immediately after formation thereof.

17. A method according to any of the previous claims, wherein said pleat tips of said first set of pleat tips being parallel and extending along a pleat direction being perpendicular to a first direction, wherein said portion of at least a subset of said pleat tips of at least one of said first set of pleat tips and said second set of pleat tips comprises a set of aligned sub-portions, arranged along said first direction on a set of adjacent pleat tips, and wherein said adjacent sub-portions define said pleat spacing structures which abut to one another after said portion deforms.

18. A method according to any of the previous claims 1 to 16, wherein said portion of at least a subset of said pleat tips of at least one of said first set of pleat tips and said second set of pleat tips comprises a set of staggered or distributed sub-portions on said pleat tips, and wherein said formed pleat spacing structures abut respective adjacent pleats.

19. A method according to any of the previous claims, wherein a distance between adjacent pleat spacing structures on a same pleat is within a range of 2 to 10 cm.

20. A method according to any of the previous claims, wherein said applying a combination of increased pressure and increased temperature comprises pressing a pressing surface, preferably a heated pressing surface, e.g. solid surface, against said portion of at least a subset of said pleat tips of at least one of said first set of pleat tips and said second set of pleat tips.21 . A method according to any of the previous claims 1 to 19, wherein said applying a combination of increased pressure and increased temperature comprises heating, for instance by hot air, infrared or other heating means and pressing a non-heated pressing surface, e.g. solid surface, against the portion of at least a subset of said pleat tips of at least one of said first set of pleat tips and said second set of pleat tips.

22. A method according to claim 20 or 21 , wherein said surface has a contact surface portion to be pressed against said pleat tips having a rounded or flat surface.

23. A method according to any of the previous claims, comprising not adding another type of pleat spacing structure.

24. A method according to any of the previous claims, wherein a width of said pleat spacing structures along said first direction is within a range of 1 to 20 mm.

25. A method according to any of the previous claims, wherein a length of a pleat spacing structure along said pleat direction is within a range of 1 to 20 mm.

26. A method according to any of the previous claims, wherein a deformation depth of a pleat spacing structure in a direction perpendicular to a plane defined by said first direction and said pleat direction is within a range of 1 to 10 mm.

27. A method according to claim 1 , wherein said pleat tips of said first set of pleat tips being parallel and extending along a pleat direction being perpendicular to a first direction, said pleat tips of said second set of pleat tips being parallel and extending along a pleat direction being perpendicular to the first direction, and the first set of pleat tips and the second set of pleat tips being parallel.

28. A pleated media filter pack comprising: a pleated media filter sheet comprising a plurality of pleat tips including a first set of pleat tips along an upstream extent and a second set of pleat tips along a downstream extent with pleat flanks extending between the first set of pleat tips and the second set of pleat tips; said pleated media filter media sheet comprising filtration media that comprises thermoplastic fibers and said pleated media filter pack comprising integrated pleat spacing structures.

29. A pleated media filter pack according to claim 28, wherein said filtration media sheet has a thickness between 0.5 and 5 mm.

30. A pleated media filter pack according to any of the previous claims 28 to 29, wherein said filtration media sheet comprises any of or any combination of thermoplastic fibers, cellulose fibers, glass fibers, or active carbon.31 . A pleated media filter pack according to claim 30, wherein said filtration media comprises active carbon.

32. A pleated media filter pack according to any of the previous claims 28 to 31 , wherein said filtration media further comprises a thermal bonding material, said thermal bonding material comprising any of or any combination of polyethylene terephthalate, nylon, or polypropylene.

33. A pleated media filter pack according to any of claims 28 to 32, wherein said filtration media sheet is a multilayer structure and comprises at least one upper sheet layer, a core layer, and at least one lower sheet layer.

34. A pleated media filter pack according to claim 33, wherein at least one of the upper sheet layer or the lower sheet layer is thermoplastic and has a melting temperature, or a minimal melting temperature of constituting components of the at least one of the upper layer or the lower sheet layer, which is higher than a melting temperature, or a minimal melting temperature of constituting components of the core layer.

35. A pleated media filter pack according to claim 34, wherein at least one of the upper layer or the lower sheet layer is thermoplastic and has a melting temperature, or a minimal melting temperature of constituting components of the at least one of the upper sheet layer or the lower sheet layer, which is lower than a melting temperature, or a minimal melting temperature of constituting components of the core layer.

36. A pleated media filter pack according to any of claims 28 to 35, wherein the upper sheet layer and / or the lower sheet layer comprise(s) a softening temperature which is higher than a softening temperature of the core layer (e.g. active carbon comprising layer).

37. A pleated media filter pack according to any of claims 28 to 35, wherein the upper sheet layer and / or the lower sheet layer comprise(s) a softening temperature which is lower than the softening temperature of the core layer (e.g. active carbon comprising layer).

38. A pleated media filter pack according to any of claims 28 to 37, wherein said predetermined portion comprises a set of aligned sub-portions, arranged along said first direction on a set of adjacent pleat tips, and wherein said adjacent sub-portions define said pleat spacing structures which abut to one another after local deformation.

39. A pleated media filter pack according to any of claims 28 to 38, wherein at least a plurality of said integrated pleat spacing structures abut respective adjacent pleats.

40. A pleated media filter pack according to any of claims 28 to 39, wherein a distance between adjacent pleat spacing structures on a same pleat tip is within a range of 2 to 10 cm.41 . A pleated media filter pack according to any of claims 28 to 40, wherein the pleated media filter pack does not include another type of pleat spacing structures.

42. A pleated media filter pack according to any of claims 28 to 41 , wherein a width of said pleat spacing structures along said first direction is within a range of 1 to 20 mm.

43. A pleated media filter pack according to any of claims 28 to 42, wherein a length of the pleat spacing structures along said pleat direction is within a range of 1 to 10 mm.

44. A pleated media filter pack according to any of claims 28 to 43, wherein a deformation depth of the pleat spacing structures in a direction perpendicular to a plane defined by said first direction and said pleat direction is within a range of 1 to 10 mm.

45. A pleated media filter pack according to any of claims 28 to 43, wherein said first set of pleat tips being parallel and extending along a pleat direction being perpendicular to a first direction, said second set of pleat tips being parallel and extending along a pleat direction being perpendicular to a first direction, and the first set of pleat tips and the second set of pleat tips being parallel.

46. A pleat spacing device comprising: a pleated media station configured to receive a pleated media pack; and a heated surface configured to move relative to the pleated media pack located in the pleated media station to cause formation of pleat spacing structure in pleat tips of the pleated media pack, and wherein the pleat spacing device is configured to provide the heated surface at a pressure of at least 5 kPa and a temperature of at least 150°Cfor a duration of 0.1 to 10 seconds to the pleat tips to cause the formation of the pleat spacing structures.

47. A pleat spacing device according to claim 46, wherein the heated surface comprises at least one wheel, at least one heated strip, or at least one heated bar.

48. A pleat spacing device according to claim 46, wherein the heated surface comprises at least one wheel and wherein the heated surface is continuous.

49. A pleat spacing device according to claim 46, wherein the heated surface comprises at least one wheel and wherein the heated surface is discontinuous.

50. A pleat spacing device according to any of claims 46-49, wherein the heated surface comprises a temperature within a range of 150°C to 300°C, more preferably between 150°C and 250°C, and more preferably between 190°C and 210°C.

51. A pleat spacing device according to any of claims 46-50, wherein the heated surface provides the pressure of 5 kPa to 200 kPa, 10 kPa to 175 kPa, or 50 kPa to 150 kPa.

52. A pleat spacing device according to claim 46, wherein the heated surface comprises at least one projection, and the at least one projection is configured to engage a recess with the pleated media therebetween.

53. A pleat spacing device comprising: a pleated media station configured to form a pleated media pack by interaction of a knife pleater construction comprising at least a first knife and an opposite second knife; at least one projection construction extending from a side of the first knife and having a pleat deformation surface; at least one recess construction on the second knife and having a pleat deformation surface; the at least pleat deformation surface on the at least one projection construction and the at least one pleat deformation surface on the recess construction being configured to receive the pleated media therebetween and provide the pleated mediatherebetween with a pressure of at least 5 kPa and a temperature of at least 150°C for a duration sufficient to cause formation of a pleat spacing structure.

54. A pleat spacing device comprising: a pleated media station configured to receive a pleated media pack; at least one hot air stream configured to blow hot air onto a surface of a pleat tip of the pleated media pack to cause deformation of the pleat tip of the pleated media pack to form a pleat spacing structure, wherein the hot air stream is configured to apply a pressure of at least 5 kPa against the pleat tip of the pleated media pack and hot air at a temperature of at least 150°C for a duration sufficient to cause formation of a pleat spacing structure; and a recess structure located opposite the pleat tip of the pleated media pack relative to the hot air stream

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