Pleated filter element for air filter

Abstract

Pleated filter element for air filter.This disclosure relates to a pleated filter element comprising: a pleated filter means comprising a principal upstream face and a principal downstream face and comprising a plurality of opposing pleats extending between said principal upstream face and said principal downstream face, such that the pleated filter means comprises a first wavy edge and a second wavy edge and a first non-wavy edge and a second non-wavy edge, wherein the pleated filter means comprises a principal pleat section and a first edge pleat section on the first non-wavy edge, wherein the length of the first edge pleat section is less than 50% of the total length of the pleated filter element between the first non-wavy edge and the second non-wavy edge and / or wherein the maximum pleat height on the first edge pleat section is less than the maximum height of pleats in the main pleats section.This disclosure also refers to an air filter comprising the filter element pleated in an enclosure.

Description

1 / 27 “Pleated Filter Element for Air Filter” FIELD OF THE INVENTION

[0001] The present invention generally relates to air filters and, more specifically, to pleated filter elements useful in air filters. Examples of applications include air intake filters for buildings, gas turbines, etc. BACKGROUND OF THE INVENTION

[0002] Air filters comprising pleated filter elements arranged in a frame structure are used in a wide range of applications. Air filters are employed in a wide range of applications, from filtering intake air in building ventilation systems to filtering intake air for large-scale industrial installations and equipment. Air filters are typically configured to be mounted in a filter retention structure. The filter retention structure may, for example, comprise a filter compartment or filter bank grid, with one or more openings into which the filters are fitted.

[0003] Examples of filter types include panel filters, deep pleated box filters, and V-type filters. Panel filters generally comprise a pleated filter element arranged in a rectangular frame. A deep pleated box filter is essentially a type of panel filter with deeper pleats, causing the rectangular frame to conform to a box shape. A V-type filter typically includes two or more pairs of pleated filter elements arranged in a V configuration. An important application for V-type filters is as intake air filters in connection with gas turbine combustion systems employed for power generation. In such applications, large volumes of air are used in the combustion process. In turn, high-volume air filtration is necessary to condition the intake air streams for Petition 870220044826, dated 05 / 24 / 2022, pp. 100 / 151 2 / 27 Combustion optimization and to reduce wear on gas turbine components. In particular, the removal of relatively small particles and liquid is important to minimize the degradation of turbine compressor blades, leading to a loss of compressor efficiency.

[0004] Each of the pleated filter elements can be made up of a pleated particulate or gas filter element. A filter element is typically formed from a sheet of filter media, for example, a sheet of fiberglass, or membrane media or non-woven polyester sheet or combinations thereof or similar, which is pleated to increase the effective filtration area of ​​the filter body. The filter media for particle separation has the specific ability to remove particles of different sizes from the air stream, depending on the type of media and, therefore, will normally conform to the ISO 16890 or EN1822 standard. A filter media for molecular filtration similarly has a specific ability to remove different types of gaseous compounds from the air stream. The gaseous compounds removed depend on the type of media.

[0005] To provide mechanical support and / or combine a plurality of filter elements, the filter elements are typically arranged in a frame structure. In order to secure the filter elements to the frame structure and prevent air from escaping the filter elements, the filter elements are typically glued and sealed against the frame structure by means of an adhesive.

[0006] In order to minimize filter pressure drop, the effective area of ​​the filter medium should be as high as possible, and obstructions to the airflow path caused by the filter frame should be as low as possible, while still providing adequate mechanical support. This is especially important in high airflow applications and applications where a high degree of separation is required, such as gas turbine applications.

[0007] Due to the leak-proof construction of the filter frame and element assembly, the adhesive used to seal the Petition 870220044826, dated 05 / 24 / 2022, pp. 101 / 151 3 / 27 Filter elements to the frame typically need to be added in liquid form to the already assembled or partially assembled filter. This can be challenging as the space available for adding the adhesive is very limited and any modification to the frame structure will usually have to be done at the expense of the amount of filter media and / or open area of ​​the filter structure, causing an increase in pressure drop. SUMMARY OF THE INVENTION

[0008] One objective of the present disclosure is to provide an air filter that solves or improves at least some of the problems associated with prior art air filters.

[0009] Another objective of this disclosure is to facilitate the addition of a liquid adhesive to seal the filter elements to the frame during production.

[0010] Another objective of this disclosure is to provide an air filter with reduced pressure drop.

[0011] The above objectives, as well as other objectives that will become apparent to a person skilled in the art in light of this disclosure, are achieved by the various aspects of the invention, as set forth in this document.

[0012] According to a first aspect of the disclosure, a pleated filter element is provided comprising:

[0013] a pleated filter means comprising an upstream principal face and a downstream principal face and comprising a plurality of opposing pleats extending between said upstream principal face and said downstream principal face, such that the pleated filter means comprises a first wavy edge and a second wavy edge and a first non-wavy edge and a second non-wavy edge, wherein the pleated filter means comprises

[0014] a main pleated section and

[0015] a first section of edge pleats in Petition 870220044826, dated 05 / 24 / 2022, pp. 102 / 151 4 / 27 first non-wavy edge, where the length of the first edge pleat section is 1 to 50% of the total length of the pleated filter element between the first non-wavy edge and the second non-wavy edge, and

[0016] where the maximum pleat height in the first edge pleat section is less than the maximum pleat height in the main pleat section.

[0017] The term corrugated, as used in this document, refers to a material or surface that is pleated or molded into a series of parallel grooves and furrows. A corrugated material will typically have two corrugated edges (e.g., zigzag-shaped) and two non-corrugated (straight) edges.

[0018] The pleated filter element is preferably rectangular in shape, and the size of the filter element is characterized by a length between the first non-corrugated edge and the second non-corrugated edge, in a direction perpendicular to the pleats, a width between the first corrugated edge and the second corrugated edge, in a direction parallel to the pleats, and a thickness between the larger upstream face and the larger downstream face, corresponding to the pleat height. The upstream and downstream principal surfaces are planes that intersect the tips of the upstream and downstream pleats, respectively. In this document, the pleat height refers to the shortest distance between the upstream principal face and the downstream principal face, i.e., typically the distance in a direction orthogonal to the upstream principal face or the downstream principal face, or both.The length and thickness refer to the total length and thickness of the filter element in the folded state and not to the length or thickness of the filter medium in the stretched state. The inventive air filter is preferably a panel-type air filter, a deep-pleated box air filter, or a V-type air filter. The total length of the pleated filter elements in such filters, between the first non-corrugated edge and the second non-corrugated edge, in a direction perpendicular to the pleats, is typically in the range of 200 to 800 mm. Petition 870220044826, dated 05 / 24 / 2022, pp. 103 / 151 5 / 27 common lengths of pleated filter elements between the first non-wavy edge and the second non-wavy edge, in a direction perpendicular to the pleats, are in the range of 200 to 700 mm, as in the range of 200 to 400 or 250 to 350 mm, or in the range of 350 to 500 or 390 to 450 mm, or in the range of 500 to 700 or 550 to 650 mm.

[0019] The pleated filter element may be arranged in an enclosure to form an air filter, such as a panel filter, a deep pleated box filter, or a V-type filter. A panel filter or a deep pleated box filter typically comprises a pleated filter element arranged in an enclosure comprising a rectangular or box-shaped frame. A V-type filter typically includes two or more pairs of pleated filter elements arranged in a V-configuration in an enclosure. The corrugated and non-corrugated edges of the filter element are typically enclosed in one or more channels in the enclosure where they may be sealed to the enclosure by adding a liquid adhesive to the channels and allowing the liquid adhesive to solidify.

[0020] The pleated filter element comprises a pleated section on the first non-corrugated edge, referred to herein as the first edge pleat section, wherein the maximum pleat height on the first edge pleat section is less than the maximum pleat height on the main pleat section. The reduced pleat height on the first edge pleat section allows the size of the channels in the housing to be reduced, thus reducing airflow path obstructions caused by the filter frame and leading to a lower overall pressure drop. The reduced pleat height on the first edge pleat section can also be used to increase the space available for adding adhesive in the channels. The reduced pleat height on the first edge pleat section can also be used to achieve a combination of reduced channel size in the housing and increased space available for adding adhesive in the channels.

[0021] Each pleated section can have a single Petition 870220044826, dated 05 / 24 / 2022, pp. 104 / 151 6 / 27 pleat height, but it is also possible that each pleat section has a band or sequence or gradient of different pleat heights. What is important for the purposes of this disclosure is that the maximum pleat height in the first edge pleat section is less than the maximum pleat height in the main pleat section. This allows the edge pleat section to fit into a smaller channel or increases the space available for adding adhesive in the channels.

[0022] The size of the pleated sections is characterized by the length of the pleated section in one direction between the first non-corrugated edge and the second non-corrugated edge. This length refers to the total length of the filter element in the folded state and not to the length of the filter medium in the stretched state. The length of the first edge pleat section may preferably be adapted to match the depth of the channel into which it is to be inserted and sealed. The channel depth may typically be in the range of a few mm to a few cm, for example in the range of 5 to 50 mm and more typically in the range of 10 to 30 mm. However, it is also possible for the first edge pleat section to be much larger, for example, so that the length of the first edge pleat section is up to 50% of the total length of the pleated filter element between the first non-corrugated edge and the second non-corrugated edge.This may, for example, be the case in a design where the pleat height tapers from a middle pleat of the pleated filter element towards the first non-wavy edge, so that the pleated filter element has a maximum pleat height at the middle pleat and a minimum pleat height at the first non-wavy edge pleat.

[0023] In some embodiments, the length of the first edge pleat section is 1 to 25%, preferably 1 to 20%, preferably 1 to 15%, preferably 1 to 10%, of the length of the pleated filter element between the first non-corrugated edge and the second non-corrugated edge. In a panel-type air filter, a box air filter Petition 870220044826, dated 05 / 24 / 2022, pp. 105 / 151 7 / 27 deep pleats or a V-type air filter, the length of the first edge pleat section in the range of 1 to 15% or 1 to 10% of the length of the pleated filter element between the first non-corrugated edge and the second non-corrugated edge is typically preferred, as it will typically correspond to the depth of the channel into which the edge pleat section is to be inserted and sealed.

[0024] The common total lengths of pleated filter elements between the first non-wavy edge and the second non-wavy edge, in a direction perpendicular to the pleats, are in the range of 200 to 700 mm, as in the range of 200 to 400 or 250 to 350 mm, or in the range of 350 to 500 or 390 to 450 mm, or in the range of 500 to 700 or 550 to 650 mm. In some designs, the length of the first section of edge pleats is in the range of 5 to 60 mm, preferably in the range of 5 to 50 mm, preferably in the range of 5 to 40 mm, preferably in the range of 5 to 30 mm, preferably in the range of 10 to 60 mm, preferably in the range of 10 to 50 mm, preferably in the range of 10 to 40 mm, preferably in the range of 10 to 30 mm, most preferably in the range of 10 to 25 mm.

[0025] The first section of edge pleats comprises a series of pleats on the first non-wavy edge. In some embodiments, the first section of edge pleats comprises at least the first two, three, four, five, six, seven, eight, nine or ten pleats on the first non-wavy edge.

[0026] In some embodiments, the pleated filter element further comprises a second section of edge pleats on the second non-wavy edge. The second section of edge pleats may be identical to the first section of edge pleats or different from the first section of edge pleats.

[0027] In some embodiments, the pleated filter element further comprises a second section of edge pleats on the second non-wavy edge, wherein the length of the second section of pleats is Petition 870220044826, dated 05 / 24 / 2022, pp. 106 / 151 8 / 27 edge is 1 to 50% of the total length of the pleated filter element between the first non-wavy edge and the second non-wavy edge, where the maximum pleat height in the pleat section of the second edge is less than the maximum pleat height in the main pleat section.

[0028] The reduced pleat height in the second edge pleat section allows the size of the channels in the housing to be reduced, thus reducing airflow path obstructions caused by the filter frame and leading to a lower overall pressure drop. The reduced pleat height in the second edge pleat section can also be used to increase the space available for adding adhesive in the channels. The reduced pleat height in the second edge pleat section can also be used to achieve a combination of reduced channel size in the housing and increased space available for adding adhesive in the channels.

[0029] Each pleat section normally has a single pleat height, but it is also possible for each pleat section to have a band or sequence or gradient of different pleat heights. What is important for the purposes of this disclosure is that the maximum pleat height in the second edge pleat section is less than the maximum pleat height in the main pleat section. This allows the edge pleat section to fit into a smaller channel or increase the space available for adding adhesive in the channels.

[0030] The length of the second edge pleat section may preferably be adapted to match the depth of the channel into which it is to be inserted and sealed. However, it is also possible for the second edge pleat section to be much longer, for example, so that the length of the second edge pleat section is up to 50% of the total length of the pleated filter element between the first non-corrugated edge and the second non-corrugated edge. This may, for example, be the case in an embodiment where the pleat height tapers from a middle pleat of the pleated filter element towards the second. Petition 870220044826, dated 05 / 24 / 2022, pp. 107 / 151 9 / 27 non-wavy edge, so that the pleated filter element has a maximum pleat height at the middle pleat and a minimum pleat height at the second non-wavy edge pleat.

[0031] In some embodiments, the length of the second edge pleat section is 1 to 25%, preferably 1 to 20%, preferably 1 to 15%, preferably 1 to 10%, of the length of the pleated filter element between the first non-corrugated edge and the second non-corrugated edge. In a panel-type air filter, a deep-pleated box air filter, or a V-type air filter, the length of the second edge pleat section in the range of 1 to 15% or 1 to 10% of the length of the pleated filter element between the first non-corrugated edge and the second non-corrugated edge is typically preferred, as it will typically correspond to the depth of the channel into which the edge pleat section is to be inserted and sealed.

[0032] The common lengths of the pleated filter elements between the first non-wavy edge and the second non-wavy edge, in a direction perpendicular to the pleats, are in the range of 200 to 700 mm, as in the range of 200 to 400 or 250 to 350 mm, or in the range of 350 to 500 or 390 to 450 mm, or in the range of 500 to 700 or 550 to 650 mm. In some designs, the length of the second section of edge pleats is in the range of 5 to 60 mm, preferably in the range of 5 to 50 mm, preferably in the range of 5 to 40 mm, preferably in the range of 5 to 30 mm, preferably in the range of 10 to 60 mm, preferably in the range of 10 to 50 mm, preferably in the range of 10 to 40 mm, preferably in the range of 10 to 30 mm, most preferably in the range of 10 to 25 mm.

[0033] In some embodiments, the second edge pleat section comprises at least the first two, three, four, five, six, seven, eight, nine or ten pleats on the second non-wavy edge.

[0034] The pleat height of the main pleat section can vary within a wide range, depending on the type of filter and the Petition 870220044826, dated 05 / 24 / 2022, pp. 108 / 151 10 / 27 total size of the filter in which the pleated filter element is to be used. In some embodiments, the pleat height in the main pleat section is in the range of 5 to 300 mm, preferably in the range of 5 to 100 mm, more preferably in the range of 10 to 50 mm, and most preferably in the range of 10 to 25 mm. A pleated filter element with a large pleat height in the range of 100 to 300 mm can be used in a deep pleated box filter. Panel filters can typically use a pleated filter element with a pleat height in the range of 25 to 100 mm, and V-type filters can typically use a pleated filter element with a pleat height in the range of 10 to 50 mm or 10 to 25 mm.

[0035] In some embodiments, the maximum pleat height in the edge pleat section(s) is 1 to 75% less than the maximum pleat height, preferably 1 to 50% less than the maximum pleat height in the main pleat section. In some embodiments, the difference in pleat height between the edge pleat section and the main pleat section corresponds to the wall thickness, typically in the range of 2 to 8 mm, of the channel in which the pleated filter element is to be sealed. This allows a main pleat section of the downstream main face or upstream main face to be flush with the outer wall of the channel.

[0036] In some embodiments, the edge pleat sections have a low pleat height to fit into a narrow channel, while the main pleat section has a significantly higher pleat height to increase the amount of filter media in a filter.

[0037] The pleat height may be reduced or decreased relative to the upstream principal face or relative to the downstream principal face or both, depending, for example, on the desired profile of the pleated filter element in the pleat section(s) of the edge. In some embodiments, the pleat height in the pleat section(s) of the edge is reduced from said upstream principal face. In some embodiments, the pleat height in the pleat section(s) of the edge is reduced from the Petition 870220044826, dated 05 / 24 / 2022, pp. 109 / 151 11 / 27 said downstream main face. In some embodiments, the pleat height on the pleat section (or sections) of the edge is reduced from both said upstream main face and said downstream main face.

[0038] In some embodiments, the pleat height in the edge pleat section(s) is reduced symmetrically from said upstream principal face and / or said downstream principal face. This type of symmetrical reduction can be especially useful when the pleated filter element is arranged straight, as in a panel-type filter.

[0039] In some embodiments, the pleat height in the pleat section (or sections) of the edge is reduced from said upstream principal face on one of the first and second non-corrugated edges and reduced from said downstream principal face on the other of the first and second non-corrugated edges. This type of asymmetrical reduction can be especially useful when the pleated filter element is arranged at an inclined angle in the filter frame, as in a V-type filter.

[0040] Each pleat section normally has a single pleat height, but it is also possible for each pleat section to have a band or sequence or gradient of different pleat heights. Thus, in some embodiments, the pleat height is the same for all pleats in the main pleat section. In some embodiments, the pleat height is the same for all pleats in the edge pleat section(s). In some embodiments, the pleat height in the edge pleat section(s) is progressively reduced towards the first or second non-pleated edge.

[0041] In some embodiments, the pleated filter element further comprises a support structure configured to maintain the pleated filter medium in a predefined rectangular shape and / or to facilitate manufacturing. The purpose of the support structure may be to maintain a desired separation between the pleats, maintain the geometric shape of the pleated filter element, and / or improve the mechanical strength of the pleated filter element during handling and use. The support structure may include a variety of Petition 870220044826, dated 05 / 24 / 2022, pp. 110 / 151 12 / 27 different resources, including, but not limited to, glue, glue cords, adhered strips, liners, edge bands and / or a frame structure. A support structure in the form of an edge band or a frame structure may be applied to one or more edges of the filter element. In preferred embodiments, an edge band or a frame structure is applied to both corrugated edges of the pleated filter element. In some embodiments, the support structure is in the form of two elongated vessels in which the first and second corrugated edges of the pleated filter element are closed and sealed by an adhesive. The elongated vessels in which the first and second corrugated edges of the pleated filter element are sealed may, in turn, be closed and sealed to the corresponding channels of a filter housing.The shape of the support structure is preferably adapted to the reduced pleat height in the edge pleat section(s), so that the pleated filter element with the attached support structure still fits into the filter housing channel as desired.

[0042] The pleated filter element according to the first aspect of the disclosure is preferably disposed in an enclosure. The enclosure seals the edges of the pleated filter element and normally allows the pleated filter element to be conveniently mounted in a filter retention structure. The filter retention structure may, for example, comprise a filter compartment or filter bank grid, with one or more openings into which the filters are fitted.

[0043] Thus, according to a second aspect of the disclosure, an air filter is provided comprising:

[0044] a pleated filter element as defined above with reference to the first aspect; and

[0045] an enclosure that has the pleated filter element disposed therein.

[0046] The air filter can be a panel filter, a Petition 870220044826, dated 05 / 24 / 2022, pp. 111 / 151 13 / 27 Deep pleated box filter or V-type filter. A panel filter or a deep pleated box filter typically comprises a pleated filter element arranged in a housing comprising a rectangular or box-shaped frame. A V-type filter typically includes two or more pairs of pleated filter elements arranged in a V-configuration in a housing. The corrugated and non-corrugated edges of the filter element are typically enclosed in one or more channels in the housing, where they may be sealed to the housing by adding and subsequently fixing a liquid adhesive to the channels.

[0047] The corrugated and non-corrugated edges of the filter element can be sealed to the housing directly or indirectly by means of an optional support structure.

[0048] In some embodiments, the air filter is a panel-type air filter comprising:

[0049] a pleated filter element as defined above with reference to the first aspect; and

[0050] an enclosure comprising a rectangular frame enclosing the pleated filter element, wherein said rectangular frame comprises a channel in which the first and second non-corrugated edges and the first and second corrugated edges of the pleated filter element are sealed by an adhesive.

[0051] The corrugated and non-corrugated edges of the filter element can be sealed to the housing directly or indirectly by means of an optional support structure.

[0052] In some embodiments, the air filter is a type V air filter comprising:

[0053] at least one pair of pleated filter elements as defined above with reference to the first aspect arranged in a V configuration;

[0054] an enclosure that has at least one pair of Petition 870220044826, dated 05 / 24 / 2022, pp. 112 / 151 14 / 27 pleated filter elements arranged therein, wherein said housing comprises at least two channels in which the first non-corrugated edges of the pleated filter elements are sealed by an adhesive, wherein an opening between said at least two channels defines a flow path for an airflow passing through the V-type air filter and

[0055] at least one channel in which the second non-corrugated edges of the pleated filter elements are sealed by an adhesive.

[0056] In some embodiments, the V-type air filter housing further comprises two side plates sealed to the first and second corrugated edges of the pleated filter elements, respectively.

[0057] The corrugated and non-corrugated edges of the filter element can be sealed to the housing directly or indirectly by means of an optional support structure.

[0058] In some embodiments, the at least two channels, in which the first non-corrugated edges of the pleated filter elements are sealed, are arranged in a front frame of the housing, said at least one channel, in which the second non-corrugated edges of the pleated filter elements are sealed, is arranged in an end plate of the housing, and said two side plates sealed to the first and second corrugated edges of the pleated filter elements are connected to the front frame and the end plate, respectively.

[0059] In some forms, the air filter of the type V comprises at least two pairs, preferably three pairs or four pairs, of pleated filter elements, each pair arranged in a V configuration.

[0060] In order to secure the pleated filter elements to the housing and prevent air from passing through the filter elements, the filter elements are typically glued and sealed against the housing by means of an adhesive. The corrugated and non-corrugated edges of the filter element may be Petition 870220044826, dated 05 / 24 / 2022, pp. 113 / 151 15 / 27 sealed to the enclosure directly or indirectly by means of an optional support structure.

[0061] In some embodiments, the air filter conforms to the international standard ISO 16890 or the EN1822 standard.

[0062] According to a third aspect of the disclosure, the use of a pleated filter element as defined above is provided with reference to the first aspect, or an air filter as defined above with reference to the second aspect, for air filtration at the air intake of a gas turbine.

[0063] Various embodiments of the invention will now be described in more detail with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] With reference to drawings, which are exemplary forms, and in which:

[0065] Figure 1a is a perspective view of a pleated filter element of the prior art;

[0066] Figure 1b is a cross-sectional view of a pleated filter element of the prior art;

[0067] Figure 2a is a perspective view of an embodiment of the inventive pleated filter element;

[0068] Figure 2b is a cross-sectional view of an embodiment of the inventive pleated filter element;

[0069] Figure 3a is a perspective view of an embodiment of the inventive pleated filter element;

[0070] Figure 3b is a cross-sectional view of an embodiment of the inventive pleated filter element;

[0071] Figure 4 is a schematic cross-sectional view of an embodiment of the inventive pleated filter element in a panel filter.

[0072] Figure 5 is a schematic cross-sectional view. Petition 870220044826, dated 05 / 24 / 2022, pp. 114 / 151 16 / 27 cross-section of an embodiment of the inventive pleated filter element in a V-type filter.

[0073] Figure 6 is a perspective view of a panel filter;

[0074] Figure 7 is a perspective view of a V-type filter;

[0075] Figure 8 is a perspective view of a Partially assembled housing of a V-type filter. DETAILED DESCRIPTION OF PREFERRED MODALITIES

[0076] Figures 1a and 1b show a pleated filter element of the prior art. The pleated filter element can be arranged in an enclosure to form an air filter, such as a panel filter, a deep pleated box filter or a V-type filter. The pleated filter element (101) consists of a pleated filter medium (102). The pleated filter element (101) has a primary upstream face (103) and a primary downstream face (104) and comprising a plurality of opposing pleats extending between the primary upstream face and the primary downstream face such that the pleated filter element comprises a first corrugated edge (105) and a second corrugated edge (106) and a first non-corrugated edge (107) and a second non-corrugated edge (108).The pleated filter element (101) is rectangular in shape and the size of the filter element is characterized by a length (L) between the first non-wavy edge (107) and the second non-wavy edge (108), in a direction perpendicular to the pleats, a width (W) between the first wavy edge (105) and the second wavy edge (106), in a direction parallel to the pleats, and a thickness (D) between the upstream principal face (103) and the downstream principal face (104), corresponding to the pleat height. The upstream and downstream principal surfaces are planes that intersect the upstream and downstream pleat tips, respectively. In this document, the pleat height refers to the shortest distance between the faces. Petition 870220044826, dated 05 / 24 / 2022, pp. 115 / 151 17 / 27 main upstream and main downstream face, i.e., typically the distance in a direction orthogonal to the main upstream face or the main downstream face, or both. The length (L) and thickness (D) refer to the total length and thickness of the filter element (101) in the folded state and not to the length or thickness of the filter medium (102) in a stretched state.

[0077] The pleated filter medium (102) may be, for example, a fiberglass sheet, or a non-woven polyester sheet or membrane medium or combinations thereof or similar, which is pleated to increase the effective filtration area of ​​the filter body. It may also be a molecular filtration medium, for example, a non-woven material containing an adsorbent for absorbing gas in particulate form, such as fibers, granules or spheres. A filter medium for particle separation has the specific ability to remove particles of different sizes from the air stream, depending on the type of medium and, therefore, will normally conform to either ISO 16890 or EN 1822 standards. A filter medium for molecular filtration similarly has a specific ability to remove different types of gaseous compounds from the air stream. The gaseous compounds removed depend on the type of medium.

[0078] Figures 2a and 2b show an embodiment of the inventive pleated filter element. The pleated filter element (201) differs from the prior art pleated filter element (101) in that it has a main pleated section (210) and a first edge pleated section (212) on the first non-wavy edge (207), wherein the maximum pleated height (He) on the first edge pleated section is less than the maximum pleated height (Hm) on the main pleated section.

[0079] The pleated filter element (201) comprises a pleated section on the first non-wavy edge, the first edge pleat section (212), wherein the maximum pleat height (He) on the first edge pleat section (212) is less than the maximum pleat height (Hm) on the main pleat section (210). An enclosure for retaining the filter element Petition 870220044826, dated 05 / 24 / 2022, pp. 116 / 151 18 / 27 pleating typically comprises several channels in which the edges of the filter element are sealed by an adhesive. The reduced pleat height in the first edge pleat section (212) allows the size of the channels in the housing to be reduced, thus reducing airflow path obstructions caused by the housing and leading to a lower overall pressure drop. Conversely, this can also allow the selection of a pleat height in the main pleat section that is higher than that which would be selected based on other space limitations. The reduced pleat height in the first edge pleat section can also be used to increase the space available for adding adhesive in the channels.The reduced pleat height in the first section of edge pleats can also be used to achieve a combination of reduced channel size in the casing, increased pleat height in the main section, and more space available to add adhesive in the channels.

[0080] In Figures 2a and 2b each pleat section has a single pleat height, but it is also possible that each pleat section has a band or sequence or gradient of different pleat heights. What is important for the purposes of this disclosure is that the maximum pleat height in the first edge pleat section (212) is less than the maximum pleat height in the main pleat section (210). This allows the edge pleat section to fit into a smaller channel or increase the space available for adding adhesive in the channels.

[0081] Figures 3a and 3b show an embodiment of the inventive pleated filter element (301) in which the pleat height in the first edge pleat section (312) is progressively reduced towards the first non-corrugated edge (307). Thus, the first edge pleat section (312) can have a low pleat height to fit into a narrow channel, while the main pleat section (310) can have a significantly higher pleat height to increase the amount of filter media in a filter.

[0082] The size of the pleated sections is characterized by the length of the pleated section in one direction between the Petition 870220044826, dated 05 / 24 / 2022, pp. 117 / 151 19 / 27 first non-corrugated edge and second non-corrugated edge. This length refers to the total length of the filter element in the folded state and not to the length of the filter medium in the stretched state. The length of the first edge pleat section may preferably be adapted to match the depth of the channel into which it is to be inserted and sealed. However, it is also possible for the first edge pleat section to be much longer, for example, so that the length of the first edge pleat section is up to 50% of the total length of the pleated filter element between the first non-corrugated edge and the second non-corrugated edge.This may, for example, be the case in a design where the pleat height tapers from a middle pleat of the pleated filter element towards the first non-wavy edge, so that the pleated filter element has a maximum pleat height at the middle pleat and a minimum pleat height at the first non-wavy edge pleat.

[0083] In some embodiments, the length of the first edge pleat section is 1 to 25%, preferably 1 to 20%, preferably 1 to 15%, preferably 1 to 10%, of the length of the pleated filter element between the first non-wavy edge and the second non-wavy edge. In some embodiments, the length of the first edge pleat section is in the range of 5 to 100 mm, preferably in the range of 5 to 50 mm, more preferably in the range of 5 to 25 mm. The first edge pleat section comprises a series of pleats on the first non-wavy edge. In some embodiments, the first edge pleat section comprises at least the first two, three, four, five, six, seven, eight, nine or ten pleats on the first non-wavy edge.

[0084] The pleated filter element may be arranged in an enclosure to form an air filter, such as a panel filter, a deep pleat box filter, or a V-type filter. A panel filter or a deep pleat box filter typically comprises a pleated filter element arranged in an enclosure comprising a rectangular frame or Petition 870220044826, dated 05 / 24 / 2022, pp. 118 / 151 20 / 27 in box form. A V-type filter typically includes two or more pairs of pleated filter elements arranged in a V configuration within a housing. The corrugated and non-corrugated edges of the filter element are typically enclosed in one or more channels in the housing where they can be sealed to the housing by adding a liquid adhesive to the channels and allowing the liquid adhesive to solidify. The corrugated and non-corrugated edges of the filter element can be sealed to the housing directly or indirectly by means of an optional support structure. The support structure may include a variety of different features, including but not limited to glue, glue beads, adhered strips, liners, edge bands, and / or a frame structure. A support structure in the form of an edge band or a frame structure may be applied to one or more edges of the filter element.In preferred embodiments, an edge band or frame structure is applied to both corrugated edges of the pleated filter element. In some embodiments, the support structure is in the form of two elongated vessels in which the first and second corrugated edges of the pleated filter element are closed and sealed by an adhesive. The elongated vessels in which the first and second corrugated edges of the pleated filter element are sealed can, in turn, be closed and sealed to the corresponding channels of a filter housing. The shape of the support structure is preferably adapted to the reduced pleat height in the edge pleat section(s), so that the pleated filter element with the attached support structure still fits into the filter housing channel as desired.

[0085] The pleat height may be reduced relative to the upstream principal face or relative to the downstream principal face or both, depending, for example, on the desired profile of the pleated filter element in the edge pleat section(s). In some embodiments, the pleat height in the edge pleat section(s) is reduced from said upstream principal face. In some embodiments, the pleat height in the section (or Petition 870220044826, dated 05 / 24 / 2022, pp. 119 / 151 21 / 27 sections) of edge pleats is reduced from said downstream principal face. In some embodiments, the pleat height in the edge pleat section(s) is reduced from said upstream principal face as well as from said downstream principal face.

[0086] In some embodiments, the pleat height in the edge pleat section(s) is reduced symmetrically from said upstream principal face and / or said downstream principal face. This type of symmetrical reduction can be especially useful when the pleated filter element is arranged straight, as in a panel-type filter.

[0087] In some embodiments, the pleat height in the pleat section (or sections) of the edge is reduced from said upstream principal face on one of the first and second non-corrugated edges and reduced from said downstream principal face on the other of the first and second non-corrugated edges. This type of asymmetrical reduction can be especially useful when the pleated filter element is arranged at an inclined angle in the filter frame, as in a V-type filter.

[0088] The pleat height of the main pleat section can vary within a wide range, depending on the filter type and the overall size of the filter in which the pleat filter element is to be used. In some embodiments, the pleat height in the main pleat section is in the range of 5 to 300 mm, preferably in the range of 5 to 100 mm, more preferably in the range of 10 to 50 mm, and most preferably in the range of 15 to 35 mm. A pleat filter element with a large pleat height in the range of 100 to 300 mm can be used in a deep pleat box filter. Panel filters can typically use a pleated filter element with a pleat height in the range of 25 to 100 mm, and V-type filters can typically use a pleated filter element with a pleat height in the range of 10 to 50 mm or 10 to 25 mm.

[0089] In some designs, the maximum pleat height in the edge pleat section(s) is 1 to 75% less than the height Petition 870220044826, dated 05 / 24 / 2022, pp. 120 / 151 22 / 27 maximum pleat height, preferably 1 to 50% less than the maximum pleat height in the main pleat section. In some embodiments, the difference in pleat height between the edge pleat section and the main pleat section corresponds to the wall thickness, typically in the range of 2 to 8 mm, of the channel in which the pleated filter element is to be sealed. This allows a main pleat section of the downstream main face or upstream main face to be flush with the outer wall of the channel.

[0090] The pleat height may be reduced relative to the upstream principal face or relative to the downstream principal face or both, depending, for example, on the desired profile of the pleated filter element in the edge pleat section(s). In some embodiments, the pleat height in the edge pleat section(s) is reduced from said upstream principal face. In some embodiments, the pleat height in the edge pleat section(s) is reduced from said downstream principal face. In some embodiments, the pleat height in the edge pleat section(s) is reduced from said upstream principal face as well as from said downstream principal face.

[0091] In some embodiments, the pleat height in the edge pleat section(s) is reduced symmetrically from said upstream principal face and / or said downstream principal face. This type of symmetrical reduction can be especially useful when the pleated filter element is arranged straight, as in a panel-type filter.

[0092] Figure 4 schematically shows the position of the pleated filter element (401) in the rectangular frame housing (420) of a panel filter (400). The pleat height in the edge pleat section(s) (412a, 412b) is symmetrically reduced from said upstream main face (403). The reduced pleat height in the first and second edge pleat sections (412a, 412b) increases the space available for adding the adhesive, as indicated by the arrows (428), in the channels (422) of the housing (420) without reducing the effective filtration area of ​​the filter element (401). Petition 870220044826, dated 05 / 24 / 2022, pp. 121 / 151 23 / 27 It is understood that the pleated filter element in Figure 4 may also have the pleat height in the edge pleat section(s) reduced symmetrically on both the upstream and downstream main faces. The reduced pleat height of both the upstream and downstream main face pleat sections increases the space available for adhesive addition in the housing channels, both upstream and downstream, without reducing the effective filtering area of ​​the filter element.

[0093] In some embodiments, the pleat height in the pleat section (or sections) of the edge is reduced from said upstream principal face on one of the first and second non-corrugated edges and reduced from said downstream principal face on the other of the first and second non-corrugated edges. This type of asymmetrical reduction can be especially useful when the pleated filter element is arranged at an inclined angle in the filter frame, as in a V-type filter.

[0094] Figure 5 schematically shows the position of the pleated filter element (501) in the housing (520) of a V-type filter (500). The pleat height in the first edge pleat section is reduced from said upstream main face (503) in the first non-corrugated edge (507) and reduced from said downstream main face (504) in the second non-corrugated edge (508). With the reduced pleat height, the upstream and downstream main faces (503, 504) are flush with the outer walls of the channels (522). The reduced pleat height in the first and second edge pleat sections allows the size of the channels in the housing to be reduced, thus reducing airflow path obstructions caused by the filter frame and leading to a lower overall pressure drop.The reduced pleat height in the first and second edge pleat sections can also be used to increase the available space for adding the adhesive, as indicated by the arrow (528), in the channels. The reduced pleat height in the first and second edge pleat sections can also be used to achieve a combination of reduced channel size in the casing and increased space. Petition 870220044826, dated 05 / 24 / 2022, pp. 122 / 151 24 / 27 available for adding adhesive to the channels. Improvements can be achieved without reducing the effective filtering area of ​​the filter element and, conversely, allowing for maximized pleat height.

[0095] The air filter will be further described with reference to embodiments in which the air filter is a panel filter and a V-type air filter, respectively.

[0096] Figure 6 shows an embodiment in which the air filter is a panel filter. The panel filter (600) has a pleated filter element (601) and a rectangular filter housing (620) which has the pleated filter element (601) disposed therein. The rectangular filter housing (620) defines a rectangular opening to receive an airflow (626) to be filtered. The pleated filter element (601) is of the type shown in Figure 4. The filter housing (620) includes a first pair of opposing side plates (620a) sealed to the corrugated edges (605, 606) of the pleated filter element and a second pair of opposing side plates (620b) sealed to the non-corrugated edges (607, 608) of the rectangular pleated filter element. The rectangular filter housing (620) comprises a channel (622) on its inward-facing surface, in which the first and second non-corrugated edges and the first and second corrugated edges of the pleated filter element (601) are sealed by an adhesive.The reduced pleat height in the first and second edge pleat sections increases the space available for adding adhesive in the housing channels without reducing the effective filtering area of ​​the filter element. It is understood that the pleated filter element in Figure 6 may also have the pleat height in the edge pleat section(s) reduced symmetrically on both the upstream and downstream larger faces. The reduced pleat height of both the upstream and downstream main face pleat sections increases the space available for adding adhesive in the housing channels, both upstream and downstream, without reducing the effective filtering area of ​​the filter element.

[0097] Figures 7 and 8 show a modality in Petition 870220044826, dated 05 / 24 / 2022, pp. 123 / 151 25 / 27 which air filter is a Type V air filter. The Type V air filter (700) comprises a filter housing (720) and several, in this embodiment, eight, rectangular pleated filter elements (701) carried by the filter housing. The pleated filter elements (701) are of the type shown in Figure 5. The filter elements (701) are arranged in pairs in a V configuration with one open end, one closed end and two V-shaped ends. Although the invention is primarily described with reference to a 4V embodiment, it is understood that the invention is equally applicable to 1V, 2V, 3V or more V configurations, i.e., filter assemblies comprising 2, 4, 6 or more filter elements.

[0098] The filter housing (720) comprises a front frame (720a), here in the form of a one-piece injection-molded front plate, two side plates (720b, 720c) and a back plate, incorporating four separate back plate elements (720d). The front frame, side plates and back plate are all provided with channels to accommodate the edges of the pleated filter elements. The front frame (720a) is rectangular and comprises a rim (724) extending peripherally and parallel channels (722a) extending between opposite sides of the front frame edge (720a).

[0099] To secure the filter elements to the housing and prevent air from passing through the filter elements, the filter elements are glued and sealed against the housing structure by means of an adhesive. The front frame is sealed to the filter elements at the open end, the rear plate elements are sealed to the filter elements at the closed end, and the two side plates are connected to the front and rear plates and sealed to the filter elements at the V-shaped ends. Consequently, the front frame, side plates and rear plate support each other to form a strong filter housing, which carries the filter elements (701).

[0100] The pleated filter elements are arranged so that the wavy edges of the rectangular pleated filter elements Petition 870220044826, dated 05 / 24 / 2022, pp. 124 / 151 26 / 27 (701) are sealed to the channels (722b, 722c) of the side plates (720b, 720c) and the non-corrugated edges of the rectangular pleated filter elements (701) are sealed to the channels (722a) of the front frame and to the channels (722d) of the rear plates, respectively.

[0101] Type V air filters are supplied in a wide variety of sizes. A common type has a substantially square front frame of approximately 600 x 600 mm. The height of the front frame can vary, but is usually 20 mm or 25 mm.

[0102] The direction of airflow through the filter is indicated by the arrow (726). The direction of the arrow is oriented as V-type filters are normally used. However, it is understood that V-type filters can also be mounted in the opposite orientation.

[0103] During operation, the air to be filtered is passed in the direction of the arrow from an upstream “dirty” side to a downstream “clean” side of the filter. The air to be filtered passes through a rectangular opening defined by the front frame and through an upstream V-shaped space defined by the pair of V-shaped filter elements, and the opposite side plates at the V-shaped end of the space. The air then passes through the porous filter medium of the filter elements to the downstream “clean” side of the filter.

[0104] The pleated filter elements of the invention allow the total open area of ​​the front frame and / or back plate(s) to be increased, since the size of the channels can be reduced. They also allow for increased space available for adding adhesive in the channels. Conversely, this can also allow for the selection of a pleat height in the main pleat section that is higher than that which would be selected based on other space limitations.

[0105] Although the invention has been described in this document with reference to several exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof, without Petition 870220044826, dated 05 / 24 / 2022, pp. 125 / 151 27 / 27 departing from the scope of the invention. Furthermore, many modifications can be made to adapt a particular situation or characteristic to the teachings of the invention, without departing from its essential scope. Therefore, it is intended that the invention is not limited to the particular embodiment disclosed as the best contemplated way to carry out this invention, but that the invention includes all embodiments that fall within the scope of the appended claims. Furthermore, it will be understood by those skilled in the art which features of the different embodiments can be combined, even if not explicitly stated above. Petition 870220044826, dated 05 / 24 / 2022, pp. 126 / 151

Claims

1 / 5 CLAIMS 1. A V-type air filter characterized in that it comprises at least one pair of pleated filter elements arranged in a V-configuration in a housing wherein said pleated filter element comprises: a pleated filter medium comprising an upstream principal face and a downstream principal face and comprising a plurality of opposing pleats extending between said upstream principal face and said downstream principal face, such that the pleated filter medium comprises a first corrugated edge and a second corrugated edge and a first non-corrugated edge and a second non-corrugated edge, wherein the pleated filter medium comprises a principal pleat section and a first edge pleat section on the first non-corrugated edge, wherein the length of the first edge pleat section is 1 to 25% of the total length of the pleated filter element between the first non-wavy edge and the second non-wavy edge,and where the maximum pleat height in the first section of edge pleats is less than the maximum pleat height in the main section of pleats.

2. V-type air filter, according to claim 1, characterized in that the length of the first edge pleat section is 1 to 20%, preferably 1 to 15%, preferably 1 to 10%, of the length of the pleated filter element between the first non-corrugated edge and the second non-corrugated edge.

3. V-type air filter, according to any of the preceding claims, characterized in that the length of the first section of edge pleats is in the range of 5 to 60 mm, preferably in the range of 5 to 30 mm, more preferably in the range of 10 to 25 mm. Petition 870240052374, dated 06 / 20 / 2024, page 18 / 26 2 / 5 4. A V-type air filter, according to any of the preceding claims, characterized in that the first edge pleat section comprises at least the first two, three, four, five, six, seven, eight, nine, or ten pleats on the first non-wavy edge.

5. A V-type air filter, according to any of the preceding claims, characterized in that it further comprises: a second edge pleat section on the second non-corrugated edge, wherein the length of the second edge pleat section is 1 to 25% of the total length of the pleated filter element between the first non-corrugated edge and the second non-corrugated edge, and wherein the maximum pleat height in the second edge pleat section is less than the maximum pleat height in the main pleat section.

6. V-type air filter, according to claim 5, characterized in that the length of the second edge pleat section is 1 to 20%, preferably 1 to 15%, preferably 1 to 10%, of the length of the pleated filter element between the first non-corrugated edge and the second non-corrugated edge.

7. V-type air filter, according to any one of claims 5 to 6, characterized in that the length of the second edge pleat section is in the range of 5 to 60 mm, preferably in the range of 5 to 30 mm, more preferably in the range of 10 to 25 mm.

8. V-type air filter, according to any one of claims 5 to 7, characterized in that the second edge pleat section comprises at least the first two, three, four, five, six, seven, eight, nine or ten pleats on the second non-wavy edge.

9. V-type air filter, according to any of the preceding claims, characterized in that the pleat height in the main pleat section is in the range of 5 to 300 mm, preferably in the range of 5 to 100 mm, more preferably in the range of 10 to 50 mm, and more preferably in the range of 15 to 35 mm.

10. V-type air filter, according to any of the preceding claims, characterized in that the maximum pleat height in the edge pleat section(s) is 1 to 75% less than the maximum pleat height, preferably 1 to 50% less than the maximum pleat height in the main pleat section.

11. V-type air filter, according to any of the preceding claims, characterized in that the pleat height in the edge pleat section(s) is reduced from said upstream principal face, from said downstream principal face, or from both said upstream principal face and said downstream principal face.

12. V-type air filter, according to any of the preceding claims, characterized in that the pleat height in the edge pleat section(s) is reduced from said upstream main face on one of the first and second non-corrugated edges and reduced from said downstream main face on the other of the first and second non-corrugated edges.

13. A V-type air filter, according to any of the preceding claims, characterized in that the pleat height is the same for all pleats in the main pleat section.

14. V-type air filter, according to any of the preceding claims, characterized in that the pleat height is the same for all pleats in the edge pleat section(s).

15. V-type air filter, according to any of the preceding claims, characterized in that the pleat height in the edge pleat section(s) is progressively reduced towards the first or second non-corrugated edge.

16. V-type air filter, according to any of the preceding claims, characterized in that said pleated filter elements further comprise a support structure configured to maintain the pleated filter medium in a predefined rectangular shape.

17. V-type air filter, according to claim 16, characterized in that the shape of said support structure is adapted to the reduced pleat height in the edge pleat section(s).

18. A V-type air filter, according to any of the preceding claims, characterized in that said housing comprises at least two channels in which the first non-corrugated edges of the pleated filter elements are sealed by an adhesive, wherein an opening between said at least two channels defines a flow path for an airflow passing through the V-type air filter, and at least one channel in which the second non-corrugated edges of the pleated filter elements are sealed by an adhesive.

19. V-type air filter according to claim 18, characterized in that said housing further comprises two side plates sealed to the first and second corrugated edges of the pleated filter elements, respectively.

20. A V-type air filter according to any one of claims 18 and 19, characterized in that said at least two channels, in which the first non-corrugated edges of the pleated filter elements are sealed, are arranged in a front frame of the housing, said at least one channel, in which the second non-corrugated edges of the pleated filter elements are sealed, is arranged in an end plate of the housing, and said two side plates, sealed to the first and second corrugated edges of the pleated filter elements, are connected to the front frame and the end plate, respectively.

21. V-type air filter, according to any of the preceding claims, characterized in that the V-type air filter comprises at least two pairs, preferably three pairs or four pairs, of pleated filter elements, each pair arranged in a V configuration. Petition 870240052374, dated 06 / 20 / 2024, page 21 / 26 5 / 5 22. Type V air filter, according to any of the preceding claims, characterized in that the air filter conforms to ISO 16890 or EN 1822.

23. Use of a V-type air filter as defined in any of claims 1 to the preceding, characterized in that it is for air filtration at the air intake of a gas turbine. Petition 870240052374, dated 06 / 20 / 2024, p. 22 / 26

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