Filter element for baghouse filtration system, and associated method of assembly

Abstract

The filter element can have a first filter section and a second filter section, each filter section having a pleated filter defining a circumferential wall of a cylindrical geometry having an axis, and an end cap at an axial end of the pleated filter, the end cap having an axial aperture; a gasket disposed axially between the end caps of the first and second filter sections, the gasket having an axial aperture fluidly connecting the axial apertures of the end caps of the first and second filter sections; a strapping ring extending circumferentially from a first circumferential end to a second circumferential end; and a fastener clamping the first circumferential end to the second circumferential end and constricting the strapping ring around the gasket and around the end caps of the first and second filter sections.

Description

FILTER ELEMENT FOR BAGHOUSE FILTRATION SYSTEM, AND ASSOCIATED METHOD OF ASSEMBLYBACKGROUND

[0001] Many countries are monitoring the impact of industrial activities on air quality due to the implication on public health. Recognizing the profound impact of air quality on human wellbeing, governments worldwide are enacting stricter regulations concerning particulate emissions. Unlike some uncontrollable natural disasters such like as wildfires, which release huge amount of particulates, emissions of industrial processes can be tamed through the utilization of appropriate equipment. Nowadays the predominant equipment employed in most industrial processes for particulate removal is the baghouse.

[0002] While existing baghouse technology has been suitable to a certain extent, as evidenced by its commercial success, there remains room for improvement.SUMMARY

[0003] In accordance with one aspect, there is provided a filter element comprising : a first filter section and a second filter section, each filter section having a pleated filter defining a circumferential wall of a cylindrical geometry having an axis, and an end cap at an axial end of the pleated filter, the end cap having an axial aperture; a gasket disposed axially between the end caps of the first and second filter sections, the gasket having an axial aperture fluidly connecting the axial apertures of the end caps of the first and second filter sections; a strapping ring extending circumferentially from a first circumferential end to a second circumferential end; and a fastener clamping the first circumferential end to the second circumferential end and constricting the strapping ring around the gasket and around the end caps of the first and second filter sections.

[0004] In accordance with another aspect, there is provided a method of assembling a filter element, the method comprising : engaging an end cap of a first filter section into a circumferential periphery of a strapping ring, against a first face of a gasket; engaging an end cap of a second filter section into the circumferential periphery of the strapping ring, against a second face of the gasket, the second face axially opposite the first face; and clamping a first circumferential end of the strapping ring onto a second circumferential end of the strappingring, thereby reducing a diameter of the strapping ring and constricting the end caps and the gasket.

[0005] In accordance with another aspect, there is provided a baghouse filtration system having a plurality of bags, each bag comprising : a plurality of filter sections connected lengthwisely to one another via corresponding ones of one or more connector assemblies, from a bottom filter section to a top filter section, the bottom filter section having a closed end opposite the corresponding connector assembly, and the top filter section having an open end opposite the corresponding connector assembly; each filter section having a cylindrical geometry with a pleated filter element extending around a circumference and along a length between two axially opposite ends of the cylindrical geometry, and at least one end cap having an annular geometry coaxial with the cylindrical geometry and provided at a corresponding one of the opposite ends; each connector assembly having a strapping ring extending circumferentially between two circumferential ends, an apertured gasket housed within the strapping ring, with facing ones of the end caps of two adjacent ones of the filter sections received within the circumference of the strapping ring, on axially opposite sides of the gasket, and a fastener clamping the two circumferential ends to one another and constricting the strapping ring around the gasket and around the facing end caps.

[0006] Many further features and combinations thereof concerning the present improvements will appear to those skilled in the art following a reading of the instant disclosure.DESCRIPTION OF THE FIGURES

[0007] In the figures,

[0008] Fig. 1 is a view of an example of a baghouse;

[0009] Fig. 2 is an oblique view of a filter element;

[0010] Fig. 3 is a cross-sectional view of a portion of a filter element, with Fig. 3A showing an enlarged portion thereof and Fig. 3B showing a gasket thereof in an expanded state;

[0011] Fig. 4 is an exploded view of a gasket and a strapping ring of a filter element;

[0012] Fig. 5 is a top plan view showing a blank for forming the strapping ring of Fig. 4;

[0013] Fig. 6 is an oblique view illustrating a process of assembling the filter element; and

[0014] Fig. 7 is a cross-sectional view, fragmented, of a portion of an end cap in accordance with an alternate embodiment, with Fig. 7A being a portion thereof shown enlarged.DETAILED DESCRIPTION

[0015] Fig. 1 shows an example baghouse filtration system, often referred to simply as a baghouse 10. The baghouse 10 can be seen have a chamber 12 which can be made of any suitable material, such as sheet metal. The chamber 12 has an air inlet 14, an air outlet 16, and generally includes a funnel-like collector section 18, a bag section 20, and a conduit section 22. The bag section 20 is separated from the conduit section 22 by an apertured partition 24. The conduit section 22 can act as a manifold, collecting the air from outlets of multiple filter elements 30 and directing it to the air outlet 16. The filter elements 30, commonly referred to as “bags”, are disposed in the bag section 20 and engaged with corresponding ones of the apertures 26.

[0016] Fig. 2 presents an example of a filter element 30. The filter element 30 can be seen to have a generally cylindrical geometry, and to have a length which is vertically-oriented in the baghouse 10. The filter element 30 can have a plurality of sections 32 which are secured to one another along the length, between a bottom, closed-ended section 34 and a top, open- ended section 36. The sections 32 can each have a generally cylindrical wall of porous filtration material 38 disposed around the circumference. The filtration material encloses a cavity which acts as a conduit, communicating internally from one section 32 to the next along the length, up through the open end of the top section 36. In a typical installation, the open-ended top section 36 has a peripheral ledge via which the filter element 30 is suspended from the partition 24, and each filter element 30 is thus configured to support the weight of each one of its sections in addition to the weight of the particles it collects in the course of normal operation.

[0017] To proceed from the air inlet 14 of the baghouse 10 to the air outlet 16 of the baghouse 10, the “dirty” air must, from the space outside the filter elements 30 in the bag section 20, cross the filters made of porous filtration material 38, into the internal conduit,thereby cleaning itself by leaving particles in the porous filtration material 38. From the internal conduit, the clean air circulates upwardly along the internal conduit, and out through the open end of the top section 36, into the conduit section 22 of the baghouse 10 where the flow from all filter elements 30 is collected / manifolded, and directed to the air outlet 16.

[0018] Once the baghouse 10 has operated for a given amount of time and the filter elements 30 have collected a certain amount of particulate matter, reverse-flow pulsations of clean air can be forced into the filter elements 30 from the open end, which can shake the filtration material and force particulates out from the porous filtration material 38, freeing the filter elements 30 from the accumulated particles. The accumulated particles can fall due to the action of gravity, into the funnel-like collector section 18, via which they can be collected and safely disposed of. As an example, during filtration operation, a pressure differential in the order of 3 kPa may be sustained across the filtration material 38, in the direction from the space surrounding the filter elements 30 into the internal conduits. During pulsating, reverse operation, a much larger pressure, such as a reverse pressure of 500 kPa, may be imparted in the direction from the internal conduit to the outside of the filter elements 30. The pulses of reverse flow may be relatively frequent, such as each 10 minutes or so, and the weight of particles accumulated by a single filter element 30 between occurrences of reverse pulses may amount to kilograms, and even tens of kilograms.

[0019] Baghouses 10 can have different sizes, ranging from those housing only a few tenths of filter elements 30 to those accommodating many thousands, and even many tens of thousands. The particle retention function can be achieved by finely woven fabric of the filtration material 38 which contains pores smaller than the particle diameter. Depending on the embodiment, the particle retention function can be achieved by a woven or a non-woven fabric material. While gas can pass through these pores, the particles become ensnared with the filtration material 38 of the filter elements 30. The baghouse capacity is not only related to the number of filter elements 30 but also on their diameter and length, which can significantly vary from one baghouse 10 to another. Typically, the filter element 30 diameter may vary between 100 and 200 mm, and the filter element 30 length may vary between 1 and 7 meters. The total capacity of a baghouse 10 is directly related to the surface area of the filtrationmaterial, which can be approximated by the equation 2Tirh*N, where r is the radius of the of the filter element 30, h is the length of the filter element, and N is the number of filter elements.

[0020] In order to enhance their profitability, the initial nominal capacity of industrial plants is constantly revised upwardly over the years. A good example of this phenomenon is an aluminum smelter plant. Where in the early 2000’s, a typical aluminum smelter plant may have been producing 200 kT of aluminum per year. More recently, a same plant may target the production of 225 kT of aluminum per year. Remarkably, this increase in production may be achieved without the addition of new electrolytic cells which are used to produce the aluminum, but rather by elevating the current density within each cell. The augmentation in current density can be correlated to a corresponding increase in baghouse capacity to ensure compliance with governmental environmental regulations regarding particulate emissions.

[0021] It is technically complex and can be very costly to add new baghouses 10 to existing plants like the afore-mentioned aluminum smelter. Normally, the plant designs do not have extra room to add bulkier baghouses. It may be more viable, if possible, to increase the capacity of existing baghouses by enhancing their filtration capabilities.

[0022] In some embodiments which are not shown, a filter element can have unpleated filter of cylindrically arranged, flat filtration material placed on a steel wire mesh cage. As an example, the filtration surface area of a 3 meter long filter having a 150 mm diameter amounts 1 ,4 m2. By removing the steel cage and replacing the unpleated filtration material by a 2 meter long pleated filter wherein the filtration material has 40 pleats and a pleat depth of 25 mm, for example, the filtration surface area can be increased to 4 m2. Even despite the shorter length, such a pleated element may offer a substantial increase in filtration area, e.g., ~2.8 times greater. An illustration of a filter element 30 having pleated filtration material is shown on Fig. 2.

[0023] Not all filtration materials are suitable to undergo pleating. Typical pleating requirements may include a degree of stiffness and compatibility with the typical hot blade pleating process, which is typically performed by specialized machinery. There can be particular challenges in increasing the length of a filter element above 2 m when it is made with pleated filtration material, considering that machinery may not be commercially available to produce pleated filtration material having more than 2 m in width (and therefore limiting thelength of the filter, when the filtration material has been pleated and arranged in a cylindrical geometry, to 2 m).

[0024] This limitation can become particularly unfortunate in cases of baghouses 10 designed for use with filter elements 30 of considerable length, e.g., reaching up to 9 meters. Simply replacing a 9-meter standard filter element with a 2-meter pleated filter element, featuring 40 pleats and a pleat depth of 25 mm, does not result in an increase in filtration surface area. For baghouses 10 employing such long filter elements 30, a solution may involve the use of two or more filter sections 32, each measuring 2 meters or less in length, and connecting such filter sections into a filter element 30. However, to achieve this in a suitable manner, certain additional factors may need to be taken into consideration, such as finding a way of connecting the filter sections 32 which does not cause leakage of air through the connector or clean air flow restriction across the connector, finding a way for the connections to support the weight of any filter sections 32 which are suspended below it, considering durability and reliability in operation, respecting the filter element 30 diameter the baghouse 10 is designed to operate with, and addressing the issues while respecting cost constraints and ease of handling.

[0025] Fig. 3 presents an example filter element 30 having a connector system 40 where a connector 42 can be used to connect two filter sections, which will be referred to herein arbitrarily as the first filter section 32A and the second filter section 32B for ease of reference. In Fig. 3, the connector system 40 is shown in an assembled configuration. Fig. 6 shows the same filter element 30 with the connector system shown disassembled.

[0026] As seen in Fig. 3 and Fig. 6, each filter section 32A, 32B has a pleated filter 44A, 44B made of a porous filtration material which has been pleated and arranged in a manner to form a circumferential wall having a cylindrical geometry with an axis 46. A porous fabric may be used, for instance. Expressions such as “radial”, “circumferential”, and “axial” are used below relative the axis 46 of the cylindrical geometry. Each filter section 32A, 32B has an end cap 48A, 48B forming an integral part of the connector system 40, details of which are shown enlarged in Fig. 3A. The end cap 48B can be disposed at an axial end of the pleated filter 44B. The filter element 30 can include two filter sections 32A, 32B, e.g., a top filter section and a bottom filter section, or more than two filter sections, in which latter case one or more intermediary filter sections may be used between the top filter section and the bottom filtersection. Any intermediary filter section may have two end caps, one at each opposite axial end thereof, whereas the top filter section and the bottom filter section may have a second end configured differently than the first end which bears the end cap.

[0027] The connector system 40 further has a connector 42 having a strapping ring 50 and a gasket 52, shown in greater detail in Fig. 4. As illustrated in Fig. 6, the filter element 30 can be assembled using a method in which the facing end caps 48A, 48B of two adjacent filter sections 32A, 32B are engaged within the circumference of the strapping ring 50 and against corresponding faces of the gasket 50, and the circumferential ends 54A, 54B of the strapping ring 50 are clamped to one another, thereby reducing a diameter of the strapping ring 50 and constricting the end caps 48A, 48B and the gasket 52. The strapping ring 50 can have annular ribs 56A, 56B, and the end caps 48A, 48B can have annular grooves 58A, 58B configured to matingly receive the annular ribs 56A, 56B (as shown in Fig. 3), in which case the method can include driving the annular ribs 56A, 56B into corresponding annular grooves 58A, 58B. When the annular ribs 56A, 56B and annular grooves 58A, 58B slope relative both the axial and radial orientations, the engagement can be designed to force the end caps 48A, 48B axially against the gasket 52 as will be detailed further below.

[0028] Referring to Fig. 3, an internal conduit 60 is formed within the circumferential wall defined by the pleated filter 44A, 44B. The end caps 48A, 48B, and the gasket 52, each have an axial aperture 62A, 62B, 64. When the connector system 40 is in the engaged configuration shown in Fig. 3, the axial apertures 62A, 62B of the end caps 48A, 48B, the axial aperture 64 of the gasket 52, and the internal conduit 60 of adjacent filter sections 32A, 32B fluidly communicate with one another, allowing clean air to circulate axially along the filter sections 32A, 32B and across the connectors 42.

[0029] Referring to Figs. 4 and 6, the strapping ring 50 can be seen to extend circumferentially between opposite circumferential ends 54A, 54B, which will be referred to herein arbitrarily as the first circumferential end 54A and the second circumferential end 54B. A fastener 66 can be used to selectively clamp the first circumferential end 54A to the second circumferential end 54B when assembling the filter element 30. More specifically, the strapping ring 50 can have a band member 68 extending circumferentially between a first shoulder 70A disposed at the first circumferential end 54A, and a second shoulder 70B disposed at the secondcircumferential end 54B. The first and second shoulders 70A, 70B may be recessed radially inwardly, within a periphery (circumference) defined by the band member 68. The fastener 66 may also be recessed within the circumference, which may help in conforming the resulting filter element 30 to a circumferential periphery closely matching the external diameter of the filters 44A, 44B. The fastener 66 can have a threaded stem, and can be configured to clamp the first shoulder 70A to the second shoulder 70B. For instance, a head of the fastener 66 can abut against the first shoulder 70A, directly or via a washer or other intermediary element, and a nut may abut against the second shoulder 70B, directly or via a washer, such as a lock washer, or other intermediary element. In an alternate embodiment, a female threaded element may be integrated to the second shoulder 70B, for instance. A thread locking adhesive such as LOCTITE® may be used on the mating threads to prevent the threads from disengaging progressively over time. In an alternate embodiment, a lock nut can be used to receive the threaded stem of the fastener.

[0030] As best seen in Fig. 4, the gasket 52 can have an elastomeric member 72 which is annular except for a recess 74, which may be referred to as a flat, defined in a radially external face. The recess 74 may correspond to, and closely match, the space occupied by the shoulders 70A, 70B and fastener 66 of the strapping ring 50, for instance, or otherwise free a space therefor in the otherwise annular geometry.

[0031] Indeed, in the illustrated embodiment, the strapping ring 52 can be made of sheet metal, an example blank of which is shown in Fig. 5. As seen in Fig. 5, the blank can have two protrusions 76A, 76B, each disposed at a corresponding end of a main body 78 thereof, and the protrusions 76A, 76B can each be configured to be folded twice to form a corresponding shoulder 70A, 70B and reinforcing member 80A, 80B. The tip of each protrusion 76A, 76B may be welded or otherwise secured to a radially internal face of the main body 68. Apertures 82A, 82B may be formed in the portions which become the shoulders 70A, 70B once folded, to allow receiving the fastener 66 thereacoss, and an elongated slot 84 may be formed adjacent one of the apertures 82A, to form an access opening when the strapping ring 50 is folded into shape. Such as shown in Fig. 6, the access opening can be used to allow access to a head of the fastener 66 across the main body 78 of the strapping ring 50.

[0032] Referring back to Fig. 3A, it can be seen, in this embodiment, that the end caps 48A, 48B can each include a mold 88, which can be made of a structural material such as sheet metal or a suitable polymer, for instance, and while the molds 88 can be generally annularly shaped, they can be open in the axial direction facing away from the gasket 52. Galvanized steel, stainless steel, aluminum or alloys may be used to make the mold 88, to name some examples. The mold 88 can receive the annular end of the pleated filtration material 44B of the filter through the axial opening, and the mold 88 can then be filled by a polymerizable material 90 which may solidify and make the annular end of the pleated filtration material 44B integral to the mold 88. In some embodiments, the external diameter of the end caps 48A, 48B can vary between 100 mm and 200 mm, and a height of 12 to 25 mm. For indicative purposes, 16 to 25 gage steel may be used, such as 22 gage steel for instance.

[0033] The end caps 48A, 48B may be forced against opposite faces of the gasket 52, and thereby clamp the gasket 52, to ensure a good seal. As shown in Fig. 4, the gasket 52 can have an elastomeric member 72 which becomes compressed when clamped by the end caps 48A, 48B. In Figs 3B and 4, the elastomeric member 72 is shown in its expanded state, and it can be wider, in the axial orientation, than in the compressed state shown in Fig. 3.

[0034] In the embodiment shown in Fig. 3, the clamping of the elastomeric member 72 by the end caps 48A, 48B can be facilitated by annular engagement features 56A, 56B, 58A, 58B formed in the strapping ring 42 and in the molds 88 of the end caps 48A, 48B. More specifically, as shown more clearly in Fig. 3A and Fig. 6, two (or more) annular engagement features 56A, 56B such as radially-inwardly directed ribs, can be formed in the strapping ring 50. Moreover, one (or more) annular feature 58A, 58B, such as a radially-inwardly directed groove can be formed in each one of the end caps 48A, 48B, and more specifically here in the molds 88 thereof. In an initial configuration, the shoulders 70A, 70B of the strapping ring 50 may be spaced-apart from one another, in which configuration the strapping ring 50 may have a larger diameter than the external diameter of the end caps 48A, 48B. In this initial configuration, the end caps 48A, 48B may easily be engaged into opposite cylindrical cavities defined in the strapping ring 50, on opposite sides of the gasket 52. From this configuration, the fastener 66 may be rotated to clamp the first shoulder 70A to the second shoulder 70B, thereby reducing the gap between the shoulders 70A, 70B and reducing the diameter of thestrapping ring 50. The annular engagement features 56A, 56B of the strapping ring 50 may radially engage the annular engagement features 56A, 56B of the end caps 48A, 48B, while being partially axially offset therefrom. The mating shape of the annular engagement features 56A, 56B, 58A, 58B, and the sloping faces, may, as the clamping continues and the gap between the shoulders 70A, 70B is further reduced, redirect the constricting action of the strapping ring 50 against the end caps 48A, 48B (and gasket 52) into a clamping action of the end caps 48A, 48B towards one another, clamping the elastomeric member 72 therebetween. The groove defined in the end caps may have a width of between 5 to 10 mm and a depth between 1 and 5 mm for instance, in some embodiments.

[0035] It will be noted that in the example presented in Figs. 3A and 6, the annular engagement features 56A, 56B, 58A, 58B, have a mating, semi-circular cross-sectional shape. It will be understood that other shapes can achieve a comparable function, and may be suitable in some embodiments. For instance, Fig. 7 and Fig. 7A show an example of an end cap where the annular engagement feature is provided in the form of radially-inwardly directed groove having a trapezoidal cross-sectional shape, which may be suitable in some embodiments. In such embodiments, the strapping ring can be provided with a mating rib also having a trapezoidal cross-sectional shape, for instance.

[0036] The elastomeric member 72 of the gasket 52 can be formed of closed-cell foamy material, or open-cell foamy material. The material can be polyurethane, ethylene, propylene, diene, monomer (EPDM) rubber, nitrile or silicon foam, or any other suitable material depending on the embodiment and depending on the intended temperature range. The thickness can be between 10 mm and 35 mm and a truncated shape can be used. The structural ring can have 30% less axial width than the elastomeric member 72 when the elastomeric member 72 is uncompressed. The structural ring can be made of galvanized steel of between 16 gage and 26 gage for instance, though other materials such as other metals or polymers like polyurethane, polyester, polypropylene may be used instead.

[0037] The constricting action of the strapping ring 50 and the clamping action of the end caps 48A, 48B towards one another may impart internal stress compressing the elastomeric member 72 of the gasket 52, and may impart bulging, or deformation which may affect fluid flow and / or the quality of the seal. In some embodiments, to avoid bulging or deformation ofthe elastomeric member 72 into the internal conduit 60, which could reduce the cross-sectional area of the internal conduit 60, a structural ring 94 may be used in the gasket 52. More specifically, a structural ring 94 having an annular shape and made of a structural material such as a suitable metal or polymer may be disposed against a radially internal face of the elastomeric member 72. The structural ring 94 may be configured to maintain its shape and size independently of any internal stresses in the elastomeric member 72 when clamped and constricted by the strapping ring 50. In the embodiment illustrated, the structural ring 94 is provided with two axially opposite annular ledges 96 which protrude radially outwardly, and bear two oppositely sloping faces, which can serve to axially locate and axially constrain the elastomeric member 72 relative the structural ring 94. In some embodiments, the strapping ring 50 may be of the same material than the end caps 48A, 48B, such as gage 16 to 26 stainless steel for instance.

[0038] Referring back to Fig. 3, in some embodiments, a perforated tube 98 may be provided radially internally to the pleated filtration material of the filter 44B, and extend along the length of the filter section 32B, connecting the end cap 48B to the other axial end of the filter section 32B (e.g., to the other end cap of an intermediary filter section or to the other corresponding structure of a top section or bottom section). The perforated tube 98 may provide some structure to resist radially-inward forces, but its purpose may mostly be to provide a mechanical link between the two ends of the filter element 30. Such a mechanical link may be particularly relevant when the filter element 30 is composed of more than two filter sections 32A, 32B, and where each filter section 32A, 32B needs to support the weight of any filter section suspended to it, and of any further filter section in the chain. A reinforcing member, such as an L shaped member for instance, may be used as an interface between the perforated tube 98 and the end cap 48B.

[0039] As can be understood, the examples described above and illustrated are intended to be exemplary only. The scope is indicated by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A filter element comprising : a first filter section and a second filter section, each filter section having a pleated filter defining a circumferential wall of a cylindrical geometry having an axis, and an end cap at an axial end of the pleated filter, the end cap having an axial aperture; a gasket disposed axially between the end caps of the first and second filter sections, the gasket having an axial aperture fluidly connecting the axial apertures of the end caps of the first and second filter sections; a strapping ring extending circumferentially from a first circumferential end to a second circumferential end; and a fastener clamping the first circumferential end to the second circumferential end and constricting the strapping ring around the end caps of the first and second filter sections.

2. The filter element of claim 1 wherein the fastener further constricts the strapping ring around the gasket.

3. The filter element of claim 1 or 2, wherein strapping ring has a band member extending circumferentially between a first shoulder of the first circumferential end and a second shoulder of the second circumferential end, the first and second shoulders being recessed radially within a circumference of the band member, the fastener having a threaded stem and clamping the first shoulder to the second shoulder, the fastener recessed radially within the circumference of the band member.

4. The filter element of claim 3 wherein the gasket is annular except for a recess defined in a radially external face thereof, the recess receiving the first and second shoulders and the fastener.

5. The filter element of any one of claims 1 to 4 wherein each filter section has a perforated tube extending axially within the pleated filter and structurally connecting the end cap to an other end of the corresponding filter section.

6. The filter element of claim 5 wherein the perforated tube extends concentrically within the pleated filter element, delimiting an inner conduit fluidly connecting the axial apertures of the gasket and of the end caps.

7. The filter element of any one of claims 1 to 6 wherein the end caps each have a sheet metal mould engaged with the gasket and filled with a polymerized material, the polymerized material securing the corresponding axial end of the pleated filter to the mould.

8. The filter element of claim 7 wherein the sheet metal moulds each have an annular engagement feature, and the strapping ring has two annular engagement features, the annular engagement features of the strapping ring each engaged with the annular engagement feature of a corresponding one of the sheet metal moulds.

9. The filter element of claim 8 wherein the annular engagement features of the sheet metal moulds are annular grooves directed radially-inwardly, and the annular engagement features of the strapping ring are annular ribs.

10. The filter element of claim 8 or 9 wherein the engagement of the annular engagement features axially clamps the end caps onto the gasket.11 . The filter element of any one of claims 1 to 10 wherein the gasket has an elastomeric member concentric and disposed around a structural ring, the elastomeric member sandwiched between the end caps and constricted by the strapping ring, the structural ring resisting compression by the elastomeric member and maintaining a diameter of the axial aperture of the gasket.

12. The filter element of claim 11 wherein the structural ring has two axially opposite annular ledges protruding radially outwardly, and axially locating the structural ring relative the elastomeric member.

13. A method of assembling a filter element, the method comprising : engaging an end cap of a first filter section into a circumferential periphery of a strapping ring, against a first face of a gasket; engaging an end cap of a second filter section into the circumferential periphery of the strapping ring, against a second face of the gasket, the second face axially opposite the first face; clamping a first circumferential end of the strapping ring to a second circumferential end of the strapping ring, thereby reducing a diameter of the strapping ring and constricting the end caps and the gasket.

14. The method of claim 13 wherein said clamping includes rotating a threaded fastener engaged with the first circumferential end and the second circumferential end.

15. The method of claim 13 or 14 wherein said clamping includes driving annular ribs defined in the strapping rings into mating annular grooves defined in the end caps.

16. The method of any one of claims 13 to 15 wherein said driving includes forcing the end caps axially against the gasket.

17. A baghouse filtration system having a plurality of bags, each bag comprising : a plurality of filter sections connected lengthwisely to one another via corresponding ones of one or more connector assemblies, from a bottom filter section to a top filter section, the bottom filter section having a closed end opposite the corresponding connector assembly, and the top filter section having an open end opposite the corresponding connector assembly; each filter section having a cylindrical geometry with a pleated filter element extending around a circumference and along a length between two axially opposite ends of the cylindrical geometry, and at least one end cap havingan annular geometry coaxial with the cylindrical geometry and provided at a corresponding one of the opposite ends; and each connector assembly having a strapping ring extending circumferentially between two circumferential ends, an apertured gasket housed within the strapping ring, with facing ones of the end caps of two adjacent ones of the filter sections received within the circumference of the strapping ring, on axially opposite sides of the gasket, and a fastener clamping the two circumferential ends to one another and constricting the strapping ring around the gasket and around the facing end caps.

18. The baghouse filtration system of claims 17, wherein strapping ring has a band member extending circumferentially between a first shoulder of the first circumferential end and a second shoulder of the second circumferential end, the first and second shoulders being recessed radially within a circumference of the band member, the fastener having a threaded stem and clamping the first shoulder to the second shoulder, the fastener recessed radially within the circumference of the band member.

19. The baghouse filtration system of claim 17 or 18 wherein the end caps each have a sheet metal mould engaged with the gasket and filled with a polymerized material, the polymerized material securing the corresponding axial end of the pleated filter to the mould.

20. The baghouse filtration system of any one of claims 17 to 19 wherein the gasket has an elastomeric member concentric and disposed around a structural ring, the elastomeric member sandwiched between the end caps and constricted by the strapping ring, the structural ring resisting compression by the elastomeric member and maintaining a diameter of the axial aperture of the gasket.

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