Improved pulse filter with integral support

Abstract

The filter element includes a tube of filter media, a first end cap, and a second end cap. The tube of filter media extends between a first end and a second end. The tube of filter media has a cylindrical outer periphery and defines a central cavity. The first end cap is secured to the first end of the tube of filter media. The first end cap includes a first opening having a first diameter. The second end cap is secured to the second end of the tube of filter media. The second end cap includes a mounting region adjacent to the second end of the tube of filter media and a first central hub positioned radially inward of the mounting region. The first central hub defines a second opening having a second diameter. The second diameter is smaller than the first diameter. A system is provided that includes one or more filter elements, a tube sheet, and an assembly yoke.

Description

[Technical Field]

[0001] The present invention relates generally to filter elements for filtering air, and more particularly to filter elements for use in gas turbine filtration systems for filtering air. [Background technology]

[0002] Systems such as gas turbine engines have filtration systems in the form of filter houses with large arrays of filter elements assembled to tube sheets by a corresponding array of assembly yokes. The filter elements may be of the "self-cleaning" type, i.e., they can be periodically cleaned in situ by a pulse of compressed air from the downstream (clean) side that temporarily reverses the flow through the pulse filter. A large array of pulse filters in a filter house typically has hundreds of filter elements, which must be replaced periodically.

[0003] The conventional geometry for filter elements in such applications has a cone element downstream of a cylindrical element. Thus, the cone element is axially located between the tube sheet and the cylindrical element. However, it is also known to have an inverted geometry, where the positions of the cone element and the cylindrical element are reversed and the cone element is upstream of the cylindrical element, as shown in U.S. Pat. Publ. No. 2015 / 0082758. To accommodate the inverted geometry, the diameter of the cylindrical element is enlarged to match the diameter of the larger diameter end of the cone element. This inverted geometry provides more filtration area in the same physical space and can improve flow distribution along the length of the filter element, resulting in reduced initial pressure drop at a given flow rate and increased filter life.

[0004] These pulse filters may be assembled into a mounting yoke, typically in the form of a tripod with three legs secured to the tube sheet or housing wall. The mounting yoke and cone filter element are sized so that the weight of the cone filter element is supported by the mounting yoke, after which the cylindrical element is installed and both elements are secured by a nut or other fastening device at the upstream end of the pulse filter.

[0005] If the configuration is reversed and the cone element is upstream of the cylindrical element, the larger-diameter cylindrical element must be installed in the assembly yoke first. Because the cylindrical elements have a constant diameter, the end of the cylindrical element farthest from the tube sheet may not be adequately supported by a tripod-shaped assembly yoke with straight legs. Therefore, while the reverse geometry improves performance, it can also increase the time and expense required by the filter installation technician. Furthermore, when a conical filter element is installed and fasteners secure it to the cylindrical filter element, any sealing gasket on the downstream end of the filter element is often angled relative to the sealing surface of the tube sheet, which can result in an air bypass.

[0006] Known prior art includes U.S. Patent Application Publication No. 2015 / 0082758, which describes a similar pulse filter design, and Japanese Patent No. 8888884, which describes an adapter used between the end of a filter element and a filter housing.

[0007] Other known prior art includes U.S. Patent Application Publication No. 2004 / 0103626, U.S. Patent No. 7,585,343, U.S. Patent Application Publication No. 2008 / 0229927, U.S. Patent No. 8,715,384, U.S. Patent Application Publication No. 2008 / 0092501, U.S. Patent No. 8,673,040, U.S. Patent No. 8,721,756, and International Publication No. 2010 / 144012.

[0008] The present invention provides an improvement over the current state of the art for filter elements, particularly filter element assemblies incorporating conical filter elements axially stacked against cylindrical filter elements within a filter house filtration system. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] US Patent Application Publication No. 2015 / 0082758 [Patent Document 2] U.S. Patent No. 8,888,884 [Patent Document 3] US Patent Application Publication No. 2004 / 0103626 [Patent Document 4] U.S. Patent No. 7,585,343 [Patent Document 5] US Patent Application Publication No. 2008 / 0229927 [Patent Document 6] U.S. Patent No. 8,715,384 [Patent Document 7] US Patent Application Publication No. 2008 / 0092501 [Patent Document 8] U.S. Patent No. 8,673,040 [Patent Document 9] U.S. Patent No. 8,721,756 [Patent Document 10] International Publication No. 2010 / 144012 Summary of the Invention

[0010] Examples include new and improved filter elements, filter element assemblies, and filter systems. In particular, examples include new and improved filter elements, filter element assemblies, and filter systems that include integrated structure in one or more filter elements for mounting the filter elements to an assembly yoke of a filter system for assembling the one or more filter elements to a tube sheet.

[0011] In one example, a filter element is provided that includes a tube of filter media, a first end cap, and a second end cap. The tube of filter media extends between a first end and a second end. The tube of filter media has a cylindrical outer periphery and defines a central cavity. The first end cap is secured to the first end of the tube of filter media. The first end cap includes a first opening having a first diameter. The second end cap is secured to the second end of the tube of filter media. The second end cap includes a mounting region adjacent to the second end of the filter media and a first central hub positioned radially inward of the mounting region. The first central hub defines a second opening having a second diameter. The second diameter is smaller than the first diameter.

[0012] Optionally, at least one flow opening is formed through the second end cap radially between the first central hub and the mounting region.

[0013] Optionally, the first central hub is attached to the attachment region by at least one spoke extending radially between the first central hub and the attachment region.

[0014] Optionally, the first central hub is attached to the mounting region by an annular region having a plurality of fluid flow holes.

[0015] Optionally, the attachment region is an annular imperforate region that forms an annular well that receives the second end of the tube of filter media.

[0016] Optionally, the mounting region has an annular radially outer sidewall, an annular radially inner sidewall, and a bottom wall extending radially therebetween, with the second end of the tube of filter media being axially received between the radially inner and outer sidewalls.

[0017] Optionally, the tube of filter media has an outer radius defined by an outer circumferential surface and an inner radius defined by an inner circumferential surface. The tube of filter media has a filter media thickness defined between the outer and inner radii. The circumferential surface of the second opening is spaced radially inward from the inner circumferential surface of the tube of filter media a distance of at least 50% of the filter media thickness at the second end.

[0018] Optionally, the second end cap includes a connection region connecting the mounting region to the first central hub.

[0019] Optionally, the connection region is provided by a nozzle extending axially toward the first end, the outlet end of the nozzle providing the second opening, the outlet end being axially positioned between the first and second ends of the tube of filter media.

[0020] Optionally, the nozzle includes a curved surface extending between the mounting region and the first central hub, the curved surface extending radially inward and axially toward the first end of the tube of filter media when viewed from the mounting region toward the first central hub, such that the nozzle has a reduced diameter when viewed from the mounting region toward the first central hub.

[0021] Optionally, the second end cap includes at least one flow directing vane that attaches the first central hub to the attachment region.

[0022] Optionally, the at least one flow directing vane is positioned radially between the attachment region and the first central hub.

[0023] Optionally, a second central hub is provided, the second central hub being axially spaced from the first central hub away from the first end of the tube of filter media, the second central hub having a third central opening having a third diameter, the third diameter being smaller than the first diameter and the second diameter.

[0024] Optionally, the second central hub is connected to at least one flow director vane, the at least one flow director vane axially connecting the first central hub to the second central hub.

[0025] Optionally, the tube of filter media defines a central axis extending axially between the first end and the second end, and the at least one flow director vane has a first vane end proximate the attachment region and a second vane end axially spaced from the first vane end toward the first end of the tube of filter media, the first vane end and the second vane end being angularly offset from one another about the central axis.

[0026] Optionally, the at least one flow director vane extends axially toward the first end cap, and when viewed axially toward the first end cap, the at least one flow director vane has a radially inner edge that tapers radially outward.

[0027] Optionally, the at least one flow directing vane is a helical vane.

[0028] Optionally, the at least one flow director vane is configured to impart an angular component to the fluid flow in the central cavity about a central axis of the tube of filter media.

[0029] Optionally, the second end cap is an end pan formed from sheet metal.

[0030] Optionally, the second diameter is at least 25%, more preferably at least 40%, of the outer diameter of the tube of filter media.

[0031] Optionally, the first central hub defines a mounting yoke surface, the mounting yoke surface facing radially inward, the mounting yoke surface at least partially defining the second opening.

[0032] In one example, a filter element assembly is provided that includes a first filter element as outlined above and a conical filter element. The conical filter element is axially aligned with the first filter element during operation. The conical filter element includes a conical section of filter media extending between a third end and a fourth end. The conical section of filter media defines a second central cavity. The second central cavity is in fluid communication with the first central cavity of the first filter element during operation. The third end has an outer diameter greater than the outer diameter of the fourth end. The second end of the tube of filter media of the first filter element has an outer diameter substantially equal to the outer diameter of the third end of the conical section of filter media of the conical filter element.

[0033] Optionally, the outer diameter of the second end of the tube of filter media of the first filter element is plus or minus 10% of the outer diameter of the third end of the conical section of the filter media of the conical filter element.

[0034] Optionally, the conical filter element includes a third end cap secured to a third end of the conical section of the filter media, the third end cap having a fourth opening with a fourth diameter, the fourth diameter being larger than the second diameter.

[0035] Optionally, the fourth diameter is substantially equal to the first diameter of the first end cap of the first filter element.

[0036] Optionally, the first end cap is substantially identical to the third end cap.

[0037] Optionally, the fourth diameter is substantially equal to the second diameter of the second end cap of the first filter element.

[0038] Optionally, the second end cap is substantially identical to the third end cap.

[0039] In one example, a filter system is provided that includes a filter element assembly according to any of the embodiments or examples outlined above, a tube sheet, and an assembly yoke, the tube sheet defining a flow opening, and the assembly yoke including a plurality of legs that taper toward each other when viewed away from the tube sheet.

[0040] Optionally, the plurality of legs of the assembly yoke include a first leg and a second leg. Each leg has a first end and a second end. The first ends are spaced apart and connected to the tube sheet. The second end of the first leg is connected to the second end of the second leg, and the first and second legs taper toward each other when viewed away from the tube sheet toward the second end. The first central hub is sized to seat a second end cap of the first filter element against the first and second legs when the filter element assembly is assembled to the assembly yoke.

[0041] Optionally, the conical filter element has a fourth end cap secured to a fourth end of the conical filter element, the fourth end cap having a non-perforated region closing the fourth end of the conical section of the filter media, the non-perforated region having an assembly hole extending therethrough through which an assembly shank of an assembly yoke extends, and a fastener attached to the assembly shank axially secures the filter element assembly to the assembly yoke and axially abuts the tube sheet, placing a first opening in the first end cap of the filter element in fluid communication with the flow opening in the tube sheet.

[0042] Optionally, a tubesheet seal seals the first end cap of the first filter element to the tubesheet.

[0043] Optionally, a filter element assembly seal seals the first filter element to the conical filter element, the first filter element and the conical filter element being separate components that are not permanently secured to one another.

[0044] Optionally, the first central hub radially engages at least one of the first leg and the second leg of the assembly yoke, and in a more particular example, the first central hub radially engages all of the legs of the assembly yoke.

[0045] Optionally, the first central hub radially engages both the first leg and the second leg.

[0046] Optionally, the assembly yoke is a tripod including a third leg having a first end and a second end, the first end being spaced apart from the first end of the first leg and the first end of the second leg and secured to the tube sheet, and the second end being secured to the second end of the first leg and the second end of the second leg. The first central hub is dimensioned to seat the second end cap of the first filter element against the first, second, and third legs when the filter element assembly is assembled to the assembly yoke.

[0047] Optionally, the conical filter element includes a third end cap secured to a third end of the conical filter medium, the third end cap having a third opening, the third opening of the third end cap of the conical filter element not being radially seated by the assembly yoke when the filter assembly is assembled to the assembly yoke.

[0048] Optionally, the conical filter element includes a third end cap secured to a third end of the conical filter medium, the third end cap having a third opening, the third opening of the third end cap of the conical filter element being seated by the assembly yoke when the filter assembly is assembled to the assembly yoke.

[0049] Optionally, the third end cap of the conical filter element is substantially identical to the second end cap of the cylindrical filter element.

[0050] In one example, a method for installing a filter element assembly between a tube sheet and an assembly yoke is provided. The tube sheet defines a flow opening. The assembly yoke extends outward from the tube sheet. The assembly yoke includes a first leg and a second leg. The legs taper toward each other when viewed away from the tube sheet. The method includes assembling a first filter element to the assembly yoke, with a first end of the first filter element axially positioned between the tube sheet and a second end of the first filter element and a first central hub of the first filter element mounted to the assembly yoke. After assembling the first filter element, the method includes assembling a conical filter element to the assembly yoke and axially abutting the conical filter element against a second end cap of the first filter element.

[0051] Optionally, the method includes axially compressing a first seal between a first end cap of the filter element and a tube sheet. The method includes axially compressing a second seal between a second end cap of the filter element and a third end cap of the conical filter element. The method includes securing the first filter element and the conical filter element to an assembly yoke using a fastener. The fastener provides the axial compression.

[0052] Optionally, a filter element for a gas turbine having an assembly yoke is provided. The filter element includes a cone element and a cylindrical element, each having opposing surfaces. An annular intermediate pan is positioned between the opposing surfaces of the cone element and the cylindrical element. The cone element, the cylindrical element, and the intermediate pan are fixed to one another. The annular intermediate pan is supported by the assembly yoke when the filter element is assembled to the gas turbine.

[0053] Optionally, the annular intermediate pan has a structure with one or more openings that allow air to flow through the length of the filter element.

[0054] Optionally, the annular intermediate pan has an aerodynamic device configured to alter the flow distribution within the filter element.

[0055] Optionally, the aerodynamic device has a configuration selected from the group consisting of one or more flow directing vanes or nozzles.

[0056] In one example, a mounting yoke having a longitudinal axis for supporting a filter element within a gas turbine is provided. The mounting yoke includes one or more support structures extending along the longitudinal axis. An annular intermediate pan is supported along the longitudinal axis by the support structures. The annular intermediate pan is configured to receive and support the filter element. The intermediate pan is fixed along the longitudinal axis of the mounting yoke to support the filter element when the filter element is assembled to the mounting yoke.

[0057] Other aspects, objects and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

[0058] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects of the invention and, together with the description, serve to explain the principles of the invention. [Brief explanation of the drawings]

[0059] [Figure 1] FIG. 1 is a perspective view of at least a portion of a filtration system according to an example. [Figure 2] FIG. 2 is an exploded view of a portion of the filtration system shown in FIG. 1, showing the filter element assembly removed from the assembly yoke and its tube sheet. [Figure 3] 1 is a cross-sectional view of a filter element assembly assembled to an assembly yoke of a filtration system. [Figure 4] 2A and 2B are perspective and partial assembly views of a filter assembly of the filtration system of FIG. 1. [Figure 5] FIG. 2 is a cross-sectional view of a filter element assembly of the filtration system. [Figure 6] FIG. 2 is an exploded view of a cylindrical filter element of the filter element assembly. [Figure 7] FIG. 7 is a cross-sectional view of a second end cap of the cylindrical filter element of FIG. 6. [Figure 8] FIG. 1 illustrates a cylindrical filter element assembled to an assembly yoke of a filtration system with the conical cone of the filter element assembly removed. [Figure 9] 10A-10C illustrate alternative embodiments of end caps for use with cylindrical filter elements, according to examples. [Figure 10] 10A-10C illustrate alternative embodiments of end caps for use with cylindrical filter elements, according to examples. [Figure 11] 10A-10C illustrate alternative embodiments of end caps for use with cylindrical filter elements, according to examples. [Figure 12] FIG. 10 is a partial view of an alternative end cap for a cylindrical filter element assembled to a mounting yoke of a filtration system, the end cap including helical vanes. [Figure 13] FIG. 13 is a cross-sectional view of the end cap and assembly yoke of FIG. 12. [Figure 14] FIG. 13 is a front view of the end cap of FIG. 12. [Figure 15] 15 is a rear view of the end cap of FIG. 12, opposite the view of FIG. 14. FIG. [Figure 16] FIG. 13 is a perspective view of the end cap of FIG. 12. [Figure 17] FIG. 13 is a perspective view of the end cap of FIG. 12. [Figure 18] 10 is a partial view of an alternative end cap for a cylindrical filter element assembled to an assembly yoke of a filtration system, the end cap including a nozzle. [Figure 19] FIG. 19 is a cross-sectional view of the end cap and assembly yoke of FIG. 18. [Figure 20] FIG. 19 is a cross-sectional view of the end cap of FIG. 18. [Figure 21] FIG. 19 is a cross-sectional view of the end cap of FIG. 18. [Figure 22] 10 is a partial view of an alternative end cap of a cylindrical filter element assembled to an assembly yoke of a filtration system, the end cap including an alternative nozzle. [Figure 23] 23 is a cross-sectional view of a cylindrical filter element assembled into an assembly yoke of a filtration system using the end cap of FIG. 22. [Figure 24] FIG. 23 is a cross-sectional view of the end cap of FIG. 22. [Figure 25] FIG. 23 is a cross-sectional view of the end cap of FIG. 22. [Figure 26] FIG. 23 is a perspective view of the end cap of FIG. 22. DETAILED DESCRIPTION OF THE INVENTION

[0060] While the present invention will be described in connection with specific preferred embodiments, it is not intended to be limited to those embodiments, but rather to cover all alternatives, modifications, and equivalents included within the spirit and scope of the invention as defined by the appended claims.

[0061] 1 illustrates a filtration system 100, more specifically, an air filtration system for filtering air for a gas turbine. While the present filtration system is particularly used in air filtration systems for gas turbines, filtration system 100 and its components may be used in other filtration systems used to filter fluids other than air, and in filtration systems used to filter fluids in downstream systems other than gas turbines.

[0062] The filtration system 100 generally includes a tube sheet 102 and a plurality of filter element assemblies 104 assembled to the tube sheet 102. The plurality of filter element assemblies 104 are arranged in an array. In some filtration systems 100, more than 100 filter assemblies 104 may be assembled to the tube sheet 102.

[0063] Filtration system 100 is provided with an optional backpulse cleaning system 106. Backpulse cleaning system 106 blows air through filter element assembly 104 from a downstream location in a direction opposite to that during normal filtration operation, thereby removing impurities from filter element assembly 104 that are separated from the fluid flowing through filter element assembly 104 during normal operation.

[0064] Typically, the tube sheet 102 is vertically oriented, with each filter element assembly 104 mounted in a cantilevered orientation. The tube sheet 102 provides a flow opening 110 adjacent to each filter assembly 104. The fluid to be filtered flows through each filter element assembly (radially in the illustrated example) and then through the associated flow opening 110.

[0065] A mounting yoke 112 positioned adjacent each flow opening 110 secures the filter element assembly 104 relative to the tubesheet 102 and supports the filter element assembly 104 in a cantilevered orientation.

[0066] 2 and 3, in this example, the assembly yoke 112 is in the form of a tripod having three longitudinally extending legs 114. Each leg 114 extends between a first end 115 and a second end 116. The first ends 115 are operably secured to the tube sheet 102 (in this example, by screws 119). The second ends 116 are secured to each other by assembly studs 118. In this example, the legs 114 taper toward each other when viewed axially away from the tube sheet 102 and toward the interconnected second ends 116.

[0067] A tubesheet seal 122 operatively seals the filter element assembly 104 to an upstream face 124 of the tubesheet 102, thereby preventing fluid bypass between the filter element assembly 104 and the tubesheet 102 as contaminated fluid flows through the filter element assembly 104 before flowing downstream.

[0068] In this example, the mounting studs 118 are threaded posts that receive fasteners 126 for securing the filter element assembly 104 to the mounting yoke 112. The fasteners can axially compress the filter element assembly 104 against the tubesheet 102, and in particular, the tubesheet seal 122.

[0069] 3-5, in this example, filter element assembly 104 includes a first filter element in the form of a cylindrical filter element 130 and a second filter element in the form of a conical filter element 132. Cylindrical filter element 130 includes a tube of filter media 133 defining a central cavity 134 that is in operative fluid communication with a central cavity 136 of a conical section of filter media 137 of conical filter element 132. In the illustrated example, filtered fluid stream 138 flows radially through filter media 133, 137, then axially within central cavities 134, 136, before exiting through flow openings 110 in tube sheet 102 (see FIG. 3).

[0070] 6, the tube of filter media 133 of the cylindrical filter element 130 extends axially between a first end 140 and a second end 142. A first end cap in the form of a first end pan 144 and a second end cap in the form of a second end pan 146 are operably secured to the first end 140 and second end 142 of the tube of filter media 133, respectively.

[0071] In this example, each end pan 144, 146 has a mounting area 147, 149 shown in the form of a bottom annular wall portion that partially defines an annular well 148, 150 that receives the corresponding end 140, 142 of the tube of filter media 133. An adhesive such as plastisol or urethane can be used to secure the end pans 144, 146 to the tube of filter media 133. The annular wells 148, 150 have an axially extending annular sidewall and a radially connecting bottom wall that extends radially between the inner and outer annular sidewalls.

[0072] The first end pan 144 defines a first opening 152 that provides an outlet opening for the filter element assembly 104 through which filtered air flows out of the filter element assembly and through the tube sheet flow openings 110. In this example, the first opening 152 is provided by the radially innermost portion of the annular well 148, e.g., the axially extending annular radially inner sidewall.

[0073] 4-7, the second end pan 146 includes a first central hub 154 that defines a second opening 156 through which filtered fluid that has passed through the filter media 137 flows into the central cavity 134 and then flows out of the filter element assembly 104.

[0074] In this example, the first central hub 154 is provided with an axially extending sidewall 158 that is operatively connected to the mounting region 149 of the second end pan 146, i.e., the second annular well 150. In this example, a plurality of spokes 160 extend radially between the radially innermost annular sidewall 161 and the first central hub 154. Intermediate flow channels 162 are formed between the spokes 160. Thus, the spokes 160 provide a connection extending between the first central hub 154 and the mounting region of the second end cap 146.

[0075] Referring to FIG. 8 , the first central hub 154 is used to mount the second end of the cylindrical filter element 130 when the cylindrical filter element 130 is assembled to the assembly yoke 112. More specifically, and with additional reference to FIG. 6 , the tube of filter media 133 of the filter element has a substantially constant outer diameter D1 and inner diameter D2 throughout its axial length. Furthermore, the first opening 152 has a diameter D3 sized to allow the assembly yoke 112 to be received through the first opening 152, thereby sealing the cylindrical filter element 130 against the tube sheet 102. Furthermore, the diameter D3 is preferably sized such that the first end pan 144 approximates an imaginary circumference defined by the legs 114 of the assembly yoke 112, thereby properly aligning the first end pan 144 with the tube sheet 102 during assembly.

[0076] However, because the assembly yoke 112 is typically tripod-shaped, or at least in the form of a tapered support structure that defines an imaginary circumference of reduced diameter when viewed axially away from the tubesheet 102, the second end pan 146 incorporates a first central hub 154 for seating the second end of the conical filter element 130 during installation. In this example, the second opening 156 provided by the central hub 154 has a diameter D4 that is smaller than diameter D3. In this case, this smaller diameter D4 allows the first central hub 154 to seat the second end of the cylindrical filter element 130 when the cylindrical filter element has been assembled to the assembly yoke 112 but the conical filter element 132 has not yet been installed, particularly before the fasteners 118 are installed. The inclusion of the first central hub 154 prevents the second end of the conical filter element 130 from pivoting or tilting under gravity toward the legs 114 due to the reduced circumference defined by the tapered configuration of the legs 114 of the assembly yoke 112.

[0077] FIG. 8 shows the first central hub 154 positioned against the legs 114 of the assembly yoke 112 with the cylindrical filter element 130 abutting the tube sheet 102, but before the conical filter element 132 is installed.

[0078] 3 and 5, conical filter element 132 includes first and second end pans 170 and 172 attached to opposite first and second ends 174 and 176, respectively, of a conical section of filter media 137. First and second end pans 170 and 172 include annular wells 178 and 180 that accommodate ends 174 and 176, respectively. First end pan 170 defines an opening 182 that fluidly connects central cavity 136 and central cavity 134 through opening 156.

[0079] The second end pan 172 has a generally imperforate region 184 that closes the open second end 176 of the conical section of the filter media 137. The imperforate region 184 includes a central assembly opening 186 that receives the assembly stud 118 of the assembly yoke 112.

[0080] In some preferred but optional embodiments, the first end pan 170 of the conical filter element 132 is identical to the first end pan 144 of the cylindrical filter element 130 .

[0081] In other examples, first end pan 170 is substantially identical to or similar to second end pan 146 of cylindrical filter element 130. In this configuration, first end pan 170 has a central hub similar to central hub 154, which serves to seat the second end of conical filter element 132 during assembly.

[0082] A filter assembly seal 188 is provided between the second end pan 146 of the cylindrical filter element 130 and the first end pan 170 of the conical filter element 132. When the filter assembly 104 is assembled to the assembly yoke 112, the fasteners 126 compress the filter element assembly 104 and also compress the filter assembly seal 188 between the cylindrical filter element 130 and the conical filter element 132, thereby forming a seal between the two filter elements 130, 132.

[0083] In a preferred embodiment, the distance D5 between the inner peripheral surface of the tube of filter media 133 and the radially inwardly directed mounting surface 190 of the first central hub 154 is at least 50% (e.g., (diameter D1-D2) / 2) of the radial thickness T of the tube of filter media. In the illustrated embodiment, the distance D5 is about 90% or more of the radial thickness T.

[0084] In one embodiment, the distance D5 between the inner circumferential surface of the filter medium 133 tube and the radially inward facing mounting surface 190 of the first central hub 154 is 25% or less of the inner diameter D2 of the filter medium 133 tube (i.e., 50% or less of the inner radius of the filter medium 133 tube).

[0085] When this applies to a conical filter element, these dimensions are measured at the axial location of the central hub relative to the axial length of the filter media of the conical filter element.

[0086] In some examples, the first end pan 144 and the second end pan 146 are formed from stamped metal, such as stamped sheet metal. However, in other embodiments, other materials, such as molded plastic, may be incorporated. Additionally, in other examples, the end caps need not include wells, and the end caps may be secured to the filter media in other ways, such as by recessing the ends of the filter media sections into the end cap mounting areas. In some examples, the end caps may be formed in situ rather than being preformed and then subsequently secured to the filter media sections.

[0087] The inclusion of opening 162 in second end pan 146 reduces flow restriction between conical filter element 132 and cylindrical filter element 130 .

[0088] 9-11 show additional embodiment second end pans 246, 346, 446. Although filter media is not shown, a tube of filter media similar to the tube of filter media 133 and a first end pan similar to first end pan 144 may be provided in combination with second end pans 246, 346, 446 to form a corresponding cylindrical filter element.

[0089] 9 shows a further embodiment of a second end pan 246. The second end pan 246 is substantially similar to the second end pan 146. However, rather than having spokes 160, the connection extending between the first central hub 254 and the mounting region 247 is provided by an annular region 261 that includes a plurality of holes 162 that help reduce flow restriction.

[0090] 10 shows a further embodiment of second end pan 346 having a connection provided by an annular region 361. In this embodiment, the connection between first central hub 354 and mounting region 347 is completely imperforate. While this design provides greater resistance, it still functions to allow a cylindrical filter element to be installed in a tapered assembly yoke.

[0091] FIG. 11 shows a further embodiment second end pan 446 that includes fewer flow openings 462 than the second end pan 146 of the first embodiment.

[0092] 12-17 show a further embodiment of second end pan 546 removed from the remainder of the cylindrical filter element but assembled to assembly yoke 112. In this embodiment, second end pan 546 includes a mounting area 547 similar to mounting area 147. Although the filter media is not shown, a tube of filter media similar to tube of filter media 133 and a first end pan similar to first end pan 144 may be provided in combination with second end pan 546 to form a corresponding cylindrical filter element.

[0093] The end pan 546 includes a plurality of flow-directing vanes in the form of helical vanes 592 that impart swirl to the clean fluid flow within the central cavity of the filter element assembly, thereby changing the radial pressure distribution at the filter outlet plane. Parameters such as the pitch and number of helical vanes 592 can be selected to reduce the overall pressure loss through the filter element and tube sheet 102. The flow-directing vanes can impart a flow component to the clean fluid flow within the filter element assembly that has a predetermined angle about the central axis of the filter element assembly.

[0094] Spiral vane 592 extends axially from a first end 593 to a second end 594. First end 593 is positioned near a first end of a filter media tube (not shown), i.e., toward tube sheet 102, and second end 594 is positioned near a second end of the filter media tube (not shown), i.e., toward threaded stud 118. Second end 594 is connected to mounting region 547. First end 593 is connected to first central hub 554. Thus, spiral vane 592 connects mounting region 547 to first central hub 554.

[0095] The first central hub 554 has an opening 556 that is sized and configured to seat the second end pan 546 on an imaginary circumference defined by the legs 114 of the assembly yoke 112. In this example, the first central hub 554 is located axially closer to the tubesheet 102 at an axial position along the assembly yoke 112.

[0096] First central hub 554 provides stability to helical blades 592 and maintains the angular spacing of first ends 593. First central hub 554 is shown attached near radially inner edge 598 of helical blades 592 near first ends 593.

[0097] The first central hub 554 has a first radius R1 (see FIG. 15).

[0098] A second central hub 595 is attached to the radially inner edge of the spiral vane 592 near the second end 594. The second central hub 595 may be configured to be located radially on the outer periphery of the legs 114. In some embodiments, the first central hub 554 is not configured to be located radially on the outer periphery of the legs 114, and only the second central hub 595 is located on the legs 114. In other embodiments, only the first central hub 554 is located radially on the outer periphery of the legs 114.

[0099] 15, the second central hub 595 has a second inner radius R2 that is smaller than the first inner radius R1. This smaller radius R2 need only accommodate a portion of the assembly yoke 112 that defines a smaller imaginary circumference.

[0100] First ends 593 of helical vanes 592 are angularly offset about a central axis 596 of second end pan 546. Furthermore, in this example, each helical vane, when viewed axially between first end 593 and second end 594, is twisted about an axis extending between first end 593 and second end 594, thereby providing the helical shape.

[0101] The spiral vanes 592 are configured to rotate the filtered fluid exiting the conical filter element and entering the corresponding cylindrical filter element, thereby reducing the pressure drop of the airflow.

[0102] The radially inner edge 598 of the spiral vane 592 tapers radially outward when viewed from the second end 594 toward the first end 593. This prevents interference between the spiral vane 592 and the legs 114 during installation, which also corresponds to the relationship that radius R1 is greater than radius R2.

[0103] In the illustrated example, the radially outer edge 599 of the spiral blade maintains a substantially constant radial distance from the central axis 596 when viewed from the second end 594 toward the first end 593.

[0104] In this example, a first central hub 554 used to mount the second end pan 546 to the assembly yoke 112 is located axially within the central cavity of the filter medium and is positioned axially between the first and second ends of the filter medium tube (e.g., the tube and ends 140, 142 of the filter medium 133).

[0105] Flow openings 562 are formed between second central hub 595 and helical vanes 592 adjacent mounting region 547. Helical vanes 592 act as spokes extending radially between second central hub 595 and mounting region 547.

[0106] As used herein, the spiral vanes 592 may have flat or curved surfaces.

[0107] 18-21 show a further example second end pan 646 for use with a conical filter element. Although the filter media is not shown, a tube of filter media similar to the tube of filter media 133 and a first end pan similar to first end pan 144 may be provided in combination with second end pan 646 to form a corresponding cylindrical filter element.

[0108] In this example, a connecting portion 667 extending between the mounting region 647 and the first central hub 654 forms the nozzle 656 .

[0109] This configuration, including the nozzle 656, increases the rate of flow through the upstream conical filter element. The nozzle 656 can also reduce the pressure drop across the filter element assembly for a given flow rate of fluid through the filter element assembly.

[0110] The outlet end of the nozzle 656 provides a first central hub 654 that mounts a cylindrical filter element to the outer periphery of the legs 114 .

[0111] 20 , the connecting portion 667 extends radially inward and axially toward the first end of the corresponding filter element (e.g., toward the tube sheet) when viewed from the mounting region 647 toward the outlet end, e.g., toward the first central hub 654. Furthermore, the connecting portion 667 is a generally curved annular sidewall. In this example, the cross-sectional shape of the connecting portion 667 is circular. In other examples, the annular sidewall may have an oval or elliptical cross-sectional shape.

[0112] In this example, the connecting portion 667 is connected to an annular radially inner sidewall that forms part of the well 650 .

[0113] In this example, a first central hub 654 used to mount the second end pan 646 to the assembly yoke 112 is located axially within the central cavity of the filter medium and is positioned axially between the first and second ends of the filter medium tube (e.g., the tube and ends 140, 142 of the filter medium 133).

[0114] 22-26 show a further example second end pan 746 for use with a conical filter element 730 (see FIG. 23). The filter media 733 and first end pan 744 are shown in FIG.

[0115] In this embodiment, an alternative nozzle 756 is formed upstream of a first central hub 754. Again, the first central hub 754 is configured to radially mount the second end pan 746 to the outer periphery of the legs 114.

[0116] A plurality of spokes 761 extend radially between the attachment region 747 and the nozzle 756 and its first central hub 754. A plurality of flow openings 762 are provided between the spokes 761, the outer circumferential surface of the nozzle 756, and the attachment region 747.

[0117] In this example, first end 771 of nozzle 756 is axially offset from the tube of filter media 733. Nozzle 756 is located within a central region of a conical filter element, such as conical filter element 132, when a corresponding filter element assembly is assembled to assembly yoke 112. In other examples (not shown), nozzle 756 may be located closer to tube sheet 102. This may require an appropriate change in the diameter of first central hub 754 to allow it to be installed in assembly yoke 112.

[0118] The inner diameter of the nozzle 756 generally decreases axially from the first end 771 toward the first central hub 754 .

[0119] This configuration, including nozzle 756, increases the rate of flow through the upstream conical filter element. Nozzle 756 can also reduce the pressure drop across the filter element assembly for a given flow rate of fluid through the filter element assembly.

[0120] The spiral vanes 592 and nozzles 656, 756 are aerodynamic devices that can affect the quantity and distribution of the pulsed cleaning flow, potentially increasing the rate of entrainment into the pulse jet and through the tubesheet by accelerating the flow within the filter element. The size and shape of the aerodynamic devices are configured so that they can fit into end pans designed to fit around the assembly yoke.

[0121] In one example, the opening provided by the central hub located in the assembly yoke 112 does not support or provide a radial seal. For example, an elastomeric or felt gasket is not adjacent the opening through the central hub to provide a direct radially inward seal.

[0122] All references cited in this specification, including publications, patent applications, and patents, are herein incorporated by reference to the same extent as if each individual reference was specifically and individually indicated to be incorporated by reference and were set forth in its entirety herein.

[0123] The use of the terms "a," "an," and "the" and similar referents in the context of describing the present invention (particularly in the context of the claims below) shall be construed to include both the singular and the plural unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" shall be construed as open-ended terms (i.e., meaning "including, but not limited to") unless otherwise indicated. The recitation of ranges of values ​​herein is intended to serve merely as a shorthand method of referring individually to each separate value falling within the range, unless otherwise stated herein, and each separate value is incorporated herein as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or clearly contradicted by context. The use of all examples or exemplary language (e.g., "such as") provided herein is intended only to better illustrate the invention and does not limit the scope of the invention unless specifically claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0124] Preferred embodiments of the invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of these preferred embodiments will become apparent to those skilled in the art upon reading the foregoing description. The inventors expect that skilled artisans will employ such variations as necessary, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Furthermore, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

1. A filter element comprising: a tube of filter media extending between a first end and a second end, the tube having a cylindrical outer periphery and defining a central cavity; a first end cap secured to the first end of the tube of filter media, the first end cap including a first opening having a first diameter; a second end cap secured to the second end of the tube of filter media, the second end cap including a mounting region adjacent the second end of the filter media and a first central hub positioned radially inward of the mounting region, the first central hub defining a second opening having a second diameter, the second diameter being smaller than the first diameter; A filter element comprising:

2. The filter element of claim 1 , wherein at least one flow opening is formed radially through said second end cap between said first central hub and said mounting region.

3. 3. The filter element of claim 1, wherein the first central hub is attached to the mounting region by at least one spoke extending radially between the first central hub and the mounting region.

4. 3. The filter element of claim 1, wherein the mounting area is an annular, imperforate area that defines an annular well that receives the second end of the tube of filter media.

5. 5. The filter element of claim 1, wherein the mounting region has an annular radially outer sidewall, an annular radially inner sidewall, and a bottom wall extending radially therebetween, and the second end of the tube of filter media is axially received between the radially inner sidewall and the radially outer sidewall.

6. 6. The filter element of claim 1, wherein the filter media tube has an outer radius defined by the outer circumferential surface and an inner radius defined by an inner circumferential surface, the filter media tube having a filter media thickness defined between the outer and inner radii, and the circumferential surface of the second opening is spaced radially inward from the inner circumferential surface of the filter media tube a distance that is at least 50% of the filter media thickness at the second end.

7. The filter element of claim 1 , wherein the second end cap includes a connection region connecting the mounting region to the first central hub.

8. 8. The filter element of claim 7, wherein the connection region is provided by a nozzle extending axially toward the first end, an outlet end of the nozzle providing the second opening, the outlet end being axially positioned between the first end and the second end of the tube of filter media.

9. 9. The filter element of claim 8, wherein the nozzle includes a curved surface extending between the mounting area and the first central hub, the curved surface extending radially inward and axially toward the first end of the tube of filter media when viewed from the mounting area toward the first central hub, such that the nozzle has a reduced diameter when viewed from the mounting area toward the first central hub.

10. 7. The filter element of claim 1, 2, or 4-6, wherein the second end cap includes at least one flow directing vane that attaches the first central hub to the mounting area.

11. The filter element of claim 10 , wherein the at least one flow director vane is positioned radially between the mounting region and the first central hub.

12. 12. The filter element of claim 10 or 11, further comprising a second central hub, the second central hub axially spaced from the first central hub away from the first end of the tube of filter media, the second central hub having a third central opening with a third diameter, the third diameter being smaller than the first diameter and the second diameter.

13. 13. The filter element of claim 12, wherein the second central hub is connected to the at least one flow director vane, the at least one flow director vane axially connecting the first central hub to the second central hub.

14. 14. The filter element of claim 10, wherein the tube of filter media defines a central axis extending axially between the first end and the second end, and the at least one flow director vane has a first vane end proximate the attachment area and a second vane end axially spaced from the first vane end toward the first end of the tube of filter media, the first vane end and the second vane end being angularly offset from one another about the central axis.

15. 15. The filter element of claim 10, wherein the at least one flow director vane extends axially toward the first end cap, and the at least one flow director vane has a radially inner edge that tapers radially outward when viewed axially toward the first end cap.

16. 16. The filter element according to claim 10, wherein the at least one flow guide vane is a helical vane.

17. 17. The filter element of claim 10, wherein the at least one flow directing vane is configured to impart an angular component to fluid flow within the central cavity about a central axis of the tube of filter media.

18. 18. The filter element of claim 1, wherein the second end cap is an end pan formed from sheet metal.

19. 19. The filter element of claim 1, wherein the second diameter is at least 40% of the outer diameter of the tube of filter media.

20. 20. The filter element of claim 1, wherein the first central hub defines an assembly yoke mounting surface, the assembly yoke mounting surface facing radially inward, and the assembly yoke mounting surface at least partially defining the second opening.

21. 1. A filter element assembly comprising: A first filter element according to any one of claims 1 to 20; a conical filter element axially aligned with the first filter element, the conical filter element comprising a conical section of filter media extending between a third end and a fourth end, the conical section of filter media defining a second central cavity, the second central cavity in fluid communication with the first central cavity of the first filter element, the third end having an outer diameter greater than an outer diameter of the fourth end, and the second end of the tube of filter media of the first filter element having an outer diameter substantially equal to the outer diameter of the third end of the conical section of filter media of the conical filter element; A filter element assembly comprising:

22. the conical filter element includes a third end cap secured to the third end of the conical section of the filter media; the third end cap has a fourth opening with a fourth diameter, the fourth diameter being greater than the second diameter; 22. The filter element assembly of claim 21.

23. The filter element assembly of claim 22 , wherein the fourth diameter is substantially equal to the first diameter of the first end cap of the first filter element.

24. 24. The filter element assembly of any one of claims 21 to 23, wherein the first end cap is substantially identical to the third end cap.

25. The filter element assembly of claim 22 , wherein the fourth diameter is substantially equal to the second diameter of the second end cap of the first filter element.

26. 26. The filter element assembly of claim 21, 22 or 25, wherein the second end cap is substantially identical to the third end cap.

27. 1. A filter system comprising: A filter element assembly according to any one of claims 21 to 26; a tube sheet defining flow openings; an assembly yoke including a first leg and a second leg, each leg having a first end and a second end, the first ends spaced apart near the tube sheet, the second end of the first leg near the second end of the second leg, and the first and second legs tapering toward each other when viewed away from the tube sheet toward the second ends; Equipped with the first central hub is sized to seat the second end cap of the first filter element against the first leg and the second leg when the filter element assembly is assembled to the assembly yoke. Filter system.

28. the conical filter element has a fourth end cap secured to the fourth end of the conical filter element, the fourth end cap having an imperforate region closing the fourth end of the conical section of the filter media, the imperforate region having an assembly hole extending therethrough through which an assembly shank of the assembly yoke extends; a fastener attached to the assembly shank, the fastener axially securing the filter element assembly to the assembly yoke and axially abutting the tube sheet to fluidly connect the first opening in the first end cap of the filter element to the flow opening in the tube sheet.

28. The filter system of claim 27.

29. 29. The filter system of claim 27 or 28, further comprising a tubesheet seal sealing the first end cap of the first filter element to the tubesheet.

30. 30. The filter system of any one of claims 27-29, further comprising a filter element assembly seal sealing the first filter element to the conical filter element.

31. 31. The filter system of any one of claims 27 to 30, wherein the first central hub is radially engaged with at least one of the first leg and the second leg.

32. 32. The filter system of any one of claims 27 to 31, wherein the first central hub radially engages both the first leg and the second leg.

33. the assembly yoke is a tripod including a third leg having a first end and a second end, the first end being fixed to the tube sheet in a spaced relation to the first end of the first leg and the first end of the second leg, and the second end being fixed to the second end of the first leg and the second end of the second leg; the first central hub is sized to seat the second end cap of the first filter element against the first leg, the second leg, and the third leg when the filter element assembly is assembled to the assembly yoke.

33. A filter system according to any one of claims 27 to 32.

34. 34. The filter system of any one of claims 27 to 33, wherein the conical filter element includes a third end cap secured to the third end of the conical filter media, the third end cap having a third opening, the third opening of the third end cap of the conical filter element not being radially seated by the assembly yoke when the filter assembly is assembled to the assembly yoke.

35. 34. The filter system of any one of claims 27 to 33, wherein the conical filter element includes a third end cap secured to the third end of the conical filter media, the third end cap having a third opening, the third opening of the third end cap of the conical filter element being radially seated by the assembly yoke when the filter assembly is assembled to the assembly yoke.

36. 36. The filter system of claim 35, wherein the third end cap of the conical filter element is substantially identical to the second end cap of the cylindrical filter element.

37. 1. A method of installing a filter element assembly on a tube sheet, the tube sheet defining a flow opening and having an assembly yoke extending outwardly from the tube sheet, the assembly yoke including a first leg and a second leg, each leg having a first end and a second end spaced apart near the tube sheet, the second end of the first leg and the second end of the second leg being adjacent to each other such that the first leg and the second leg taper toward each other when viewed away from the tube sheet toward the second end, the method comprising:

21. Assembling the filter element of any one of claims 1 to 20 to the assembly yoke, wherein the first end of a first filter element is axially positioned between the tube sheet and the second end of the first filter element and the first central hub is mounted to the assembly yoke; after assembling the first filter element, assembling a conical filter element into the assembly yoke so that the conical filter element axially abuts the second end cap of the first filter element; A method comprising:

38. axially compressing a first seal between the first end cap of the filter element and the tube sheet; axially compressing a second seal between the second end cap of the filter element and a third end cap of the conical filter element; securing the first filter element and the conical filter element to the assembly yoke using fasteners that provide the axial compression; 38. The method of claim 37, further comprising:

39. 1. A filter element for a gas turbine having an assembly yoke, comprising: a first section and a second section; the first section having an upper end pan attachable to the assembly yoke and the second section having a lower end pan with an annular opening positionable against a filter housing to thereby connect the filter element to a flow opening; the lower end pan having an aerodynamic device surrounding the annular opening; the aerodynamic device has a configuration that alters the flow distribution within the filter element. Filter element.

40. 40. The filter element of claim 39, wherein the aerodynamic device has a configuration selected from the group consisting of one or more helical vanes, nozzles, or ejectors.

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