FILTER ELEMENT, MULTI-ELEMENT FILTER APPARATUS AND MULTI-ELEMENT APPARATUS

Abstract

A multi-element filtration vessel contains multiple filtration elements. The elements have cylindrical housings and an annular header. At least a portion of the annular header surrounds the cylindrical housings at one end. The annular header has a periodically varying cross-sectional width and thickness such that the annular header has alternating thinner and thicker regions. The elements are packed with thinner sections of the header aligned. This allows for close packing of the elements without unduly compromising the mechanical strength of the headers.

Description

1 / 18 “FILTRATION ELEMENT, MULTI-ELEMENT FILTRATION APPARATUS AND MULTI-ELEMENT APPARATUS” Field of the Invention

[001] This invention relates to multi-element filtration vessels. Background of the Invention

[002] Multi-element filtration vessels are widely used in water treatment plants to purify water. Semi-permeable membranes are mounted within elements, which are mounted vertically in an array inside the vessel. A feed fluid is fed through the elements, where it is separated by the membranes into a concentrate and a permeate. A mixing gas is usually introduced into the vessel at a point below the elements. The mixing gas can perform several useful functions. When the membrane is of the hollow fiber type, gas bubbles provide buoyancy, aiding in the transfer of the feed fluid between fibers or through capillaries in the fibers. The mixing gas can also perform a cleaning function and improve fluid mixing.

[003] Filtration elements generally include a cylindrical housing containing the membrane(s). A collector is fitted to one end of the cylindrical housing. The collector is an annular piece that fits over the cylindrical housing. Its external transverse dimensions are larger than the external dimensions of the cylindrical housing. The larger diameter means that fewer filtration elements can be packed within a pressure vessel of a given size. Increasing the number of filtration elements within a vessel increases its capacity. For large installations, this can mean that fewer filtration vessels are needed and / or that the cost of the vessels can be spread over a larger number of filtration elements. This would greatly reduce both equipment and operating costs. An improved element area ratio of Petition 870250041411, dated 05 / 20 / 2025, page 41 / 74 2 / 18 filtration for vessel cost can also be achieved through more efficient packing. For example, the existence of edge effects within a vessel of filtration elements can allow non-regular packing geometries to exceed the efficiency of compact geometries.

[004] Filtration elements are typically cylindrical in shape, and the collectors used with them are also generally cylindrical. Making the collector walls thinner can reduce the overall cross-section of the filtration element, but in doing so, the collector may be weakened to the point where it can no longer tolerate the physical stresses incurred during handling, transport, and use. Thus, the collector walls tend to be quite thick, thereby increasing the cross-sectional dimensions of the filtration elements and limiting how tightly the elements can be packed within the pressure vessel. Brief Description of the Invention

[005] This invention addresses this problem by providing a filtration element comprising: a) a cylindrical housing having an outer diameter, the cylindrical housing surrounding an inner portion of the filter element, the cylindrical housing having first and second opposite ends; b) at least one filtration membrane disposed within the inner portion of the filtration element; c) one or more openings to admit a feed fluid through at least one of the first and second opposite ends of the cylindrical housing and into the inner portion of the filter element; d) an annular collector including a surrounding section that encircles one of the opposite ends of the cylindrical housing, the surrounding section having a periodically varying transverse width and thickness Petition 870250041411, dated 05 / 20 / 2025, page 42 / 74 3 / 18 variables, so that the surrounding section of the annular collector has alternating thinner and thicker regions, and (e) Separate openings for removing permeate and concentrate from the filtration element.

[006] Due to the periodically varying cross-sectional width, the surrounding section of the annular collector has alternating thinner and thicker regions, the thinner regions being periodically (and preferably regularly) spaced around the circumference of the surrounding section of the annular collector. The thinner regions can be made quite small, such as 1-3 mm or less thick, because mechanical strength is provided by the alternating thicker regions. When packed into a multi-element filtration apparatus, the thinner regions of the annular collectors are aligned, allowing adjacent filtration elements to be packed closer together.

[007] The invention is also a multi-element filtration apparatus, the apparatus comprising: a) a pressure vessel having a cylindrical shell; b) Multiple filtration elements of the invention arranged vertically within the cylindrical casing of the pressure vessel, wherein adjacent filtration elements are aligned along thinner regions of the annular collector sections surrounding the respective permeate ends of the cylindrical housings of the adjacent filtration elements; a feed inlet port for introducing a feed fluid into the pressure vessel; a permeate discharge port for discharging permeate produced by the multiple filtration elements from the pressure vessel; and a concentrate discharge port for discharging concentrate produced by the multiple filtration elements from the pressure vessel. Petition 870250041411, dated 05 / 20 / 2025, page 43 / 74 4 / 18 filtration elements. Brief Description of the Figures

[008] Figure 1 is a front view, in section, of a first embodiment of a multi-element filtration apparatus of the invention.

[009] Figure 2 is a front view, partially in section, of a filtration element of the invention.

[010] Figure 3 is an isometric view of one end of a filtration element of the invention with an attached end cap.

[011] Figure 4 is an isometric view of an annular collector for use in the invention.

[012] Figure 5 is an isometric sectional view of an annular collector for use in the invention.

[013] Figure 5A is an isometric sectional view of a top section of a filtration element of the invention.

[014] Figure 6 is a top sectional view of an annular collector for use in the invention.

[015] Figure 7 is a side view of an annular collector for use in the invention.

[016] Figure 7A is a rotated view of the annular collector shown in Figure 7.

[017] Figure 8 is a top view of an arrangement of filtration elements of the invention.

[018] Figure 9 is a top view of a module package inside a pressure vessel with a support plate.

[019] Figure 10 is a front view, in section, of a second embodiment of a filtration apparatus of the invention. Detailed Description of the Invention

[020] Returning to Figure 1, the filtration apparatus Petition 870250041411, dated 05 / 20 / 2025, page 44 / 74 5 / 18 multi-element (15) includes the pressure vessel (1), which in the embodiment shown includes the casing (2) and the removable cover (9). Preferably, the casing (2) is cylindrical and the pressure vessel (1) is suitable for operation with internal pressures exceeding at least two bar above the external pressure. A filtration chamber (16) is surrounded by the casing (2) and the pressure plate (18). The filtration elements (3) are arranged vertically within the filtration chamber (16). In this embodiment, the filtration elements (3) are aligned and supported by at least one of the pressure plate (18), the support plate (13) and the lower support plate (12). The support plate (13), as shown, includes openings to receive filtration elements (3) so that the collectors (22) rest on the support plate (13).

[021] In the embodiment shown in Figure 1, the feed fluid to be treated is introduced under pressure into the multi-element filtration apparatus (15) through the inlet port (4), where it passes through the openings in the lower support plate (12) and enters the filtration elements (3) through the holes (27) at the first ends (24) of the filtration elements (3) (see Figure 2). The filtration elements (3) contain one or more membranes (26) (Figure 2), which allow the passage of a portion of the feed fluid, thus producing permeate (or filtrate) and a concentrate (or reject) stream containing a small portion of the feed fluid plus materials that do not pass through the pores of the membrane.

[022] In the embodiment shown in Figures 1, 3 and 4, the concentrate is removed from the filtration elements (3) through the openings (33) in the annular collector (22) and removed from the pressure vessel (1) through the concentrate port (6). In alternative embodiments, instead of or in addition to the openings (33), openings for removing the concentrate from the filtration elements (3) may be present within the cylindrical housing (21). In both cases, the permeate passes through the central opening (35) of the collector. Petition 870250041411, dated 05 / 20 / 2025, page 45 / 74 6 / 18 annular collector (22) to the collection chamber (10) of the pressure vessel (1), from which it is removed through the permeate port (5). In the particular embodiment shown, the optional end cap (23) is mounted on the annular collector (22) and forms a conduit for the permeate to exit from the central opening (35) to the collection chamber (10), the permeate flowing to the collection chamber (10) through the outlet (34) of the end cap (23). As shown, the end cap (23) extends through the pressure plate (18). Alternatively, the annular collector (22) may be in fluid communication with the collection chamber (10) through openings in the pressure plate (18). The collection chamber (10) during operation is generally maintained at a lower pressure than the filtration chamber (16). The filtration element (3) and the pressure vessel (1) can alternatively be designed so that the concentrate passes through the outlets (34) and the permeate is removed through the port (6).This can be done, for example, by operating in an inside-out mode with both the upper and lower ends of the hollow fiber membranes being open.

[023] The optional aerator (11) provides a mixing gas which is introduced into the first ends (24) of the filter elements (3). The introduction of both the gas and the feed fluid from the lower end of the filter element (3) can induce an upward force in the feed fluid to drive the concentrate towards the openings (33). The openings (33) for the concentrate may be in the cylindrical housing (21) or in the collector (22), but these openings (33) are separated from the permeate outlet (34) by a seal, such as an encapsulation layer (31), as shown in Figure 5.

[024] Although the embodiment shown in Figure 1 is designed to operate with the feed fluid being introduced from the bottom and the concentrate and permeate being removed from the top, in alternative embodiments the multi-element filtration apparatus (15) Petition 870250041411, dated 05 / 20 / 2025, page 46 / 74 7 / 18 can be configured to operate with the feed fluid being introduced from the top and the concentrate being removed from the bottom. Furthermore, the embodiment shown in Figure 1 can alternatively be designed with openings in the support plate (13) that allow the concentrate to drain into the filtration chamber (16), from which it can be removed through a suitable door.

[025] Returning to Figure 2, the filtration element (3) includes a cylindrical housing (21), which encloses an internal space in which one or more filtration membranes (26) are arranged. The filtration element (3) has first and second opposite ends (24 and 25) at opposite ends of the cylindrical housing (21). During normal operation, a feed fluid is introduced at the first end (24) through inlet holes (27), and the permeate and concentrate flow out of the second end (25) to the annular collector (22). In the embodiment shown in Figure 2, the inlet holes (27) pass through the lower end of an encapsulation layer (31). The inlet holes (27) may alternatively pass through the optional collar (29) or through a location in the cylindrical housing (21), below the encapsulation layer (31). The optional collar (29) can cover the first end (24).The optional end cap (23) is mounted on the annular collector (22); in the particular embodiment shown, the end cap (23) is in fluid communication with the annular collector (22) and the collection chamber (10) of the pressure vessel (1), to allow the permeate to flow out of the filtration element (3) and, in the embodiment shown in Figure 1, into the collection chamber (10).

[026] The annular collector (22) has the general shape of a ring with a central opening (35). The portion of the central opening (35) that surrounds the cylindrical housing (21) is generally circular to match the external shape of the cylindrical housing (21). Petition 870250041411, dated 05 / 20 / 2025, page 47 / 74 8 / 18

[027] The annular manifold (22) includes a surrounding section (30) that encircles one end (as shown, second end (25)) of the cylindrical housing (21). The surrounding section (30) has a periodically varying transverse width, as shown in more detail in Figure 6. Starting at any arbitrary point A on the outer surface of the surrounding section (30) of the annular manifold (22), the transverse width of the surrounding section (30) changes periodically around the circumference of the surrounding section (30). Thus, in Figure 6, the surrounding section (30) has a transverse width Wmax at point A. Moving clockwise around the surrounding section (30), as shown in Figure 6, the transverse width first decreases, reaching Wmin < Wmax at point B, then increases to reach Wmax again at point C, and subsequently decreases and increases periodically between Wmin and Wmax until it returns to the initial point A.This produces alternating thinner regions (52) and thicker regions (53), reaching relative minima at points such as point B, where the width decreases to Wmin. Thinner regions (52) are periodically (and preferably regularly) spaced around the circumference of the section (30) of the annular collector (22). The periodic variation in the thickness of the surrounding section (30) produces relative minima, which preferably appear at repetition intervals of 30 to 120 degrees, and more preferably at repetition intervals of 60 degrees.

[028] Thinner sections (52) may have thicknesses, at their thinnest point, in the range of, for example, 0.5 to 3 mm. Thicker sections (53), at their thickest point, may have thicknesses, for example, 1.4 to 5 times the minimum thickness of thinner sections (52), such as, for example, 1 to 15 mm, especially 2 to 8 mm.

[029] In the particular embodiment shown in Figures 37A, the surrounding section (30) of the annular collector (22) has a section shape Petition 870250041411, dated 05 / 20 / 2025, page 48 / 74 9 / 18 external hexagonal cross-section generally regular preferred. The vertices (50) may be rounded or chamfered, if desired, instead of forming sharp points, as shown in Figures 3-7A. The sides (51) of the surrounding section (30) are preferably flat, as shown in Figure 5. Alternatively, the surrounding section (30) may have any arbitrary number of sides, ranging from just three (being generally triangular in cross-section in that case), four or five, or as many as, for example, 12, 10 or 8 sides.

[030] At all points on the circumference of the filter element (3), the surrounding section (30) preferably has the largest transverse width of any component of the filter element (3). Especially at points on the circumference of the filter element (3) corresponding to regularly spaced relative minima in the surrounding section (30), Wmin is preferably equal to or greater than the transverse width of each of the cylindrical housing (21), any optional collar (29) and any end cap (23). Referring to Figures 7 and 7A, the minimum width Wmin of the surrounding section (30) of the annular collector (22) is equal to or greater than the transverse width D of the cylindrical housing (21), and the maximum width Wmax of the surrounding section (30) is greater than the transverse width D.The end cap (23), as well as any collar (29) or other components that may be present, have a minimum width that is less than or equal to Wmin and a maximum width that is preferably not greater than Wmin. Preferably, at any point on the circumference of the filter element (3), any collar (29) and end cap (23) have a transverse width equal to or less than that of the corresponding surrounding section (in the same radial position) (30) of the annular collector (22) at that point. The collar (29), when present, may have a periodically variable transverse width, as described in relation to the surrounding section (30) of the annular collector (22). Petition 870250041411, dated 05 / 20 / 2025, page 49 / 74 10 / 18

[031] Each membrane (26) can be, for example, a microfiltration membrane, an ultrafiltration membrane, a nanofiltration membrane or a reverse osmosis membrane. The most preferred is an ultrafiltration membrane. In a preferred embodiment, the membranes take the form of hollow fiber membranes, but they can be spirally wound or have other configurations if desired.

[032] Preferred hollow fiber membranes are encapsulated within the filtration element (3), typically at both opposite ends (24, 25) of the filtration element (3). The capillary openings of the hollow fiber membranes are open at at least one end of the filtration element (3). In certain embodiments adapted for an outside-in permeation mode of operation, the capillary openings may be open at both ends, but are preferably closed at one end. The capillaries may be blocked at the first end (24), such as by being buried within the encapsulation, and the capillaries may be open and extend through the encapsulation at the second opposite end (25) to allow permeate to exit the element.Referring to the configuration illustrated in Figure 2, an encapsulation layer (31') seals the capillaries of the hollow fiber membranes (26), but the encapsulation layer (31') also contains inlet holes (27) that pass through the encapsulation layer (31') and allow the feed fluid to enter the filtration element (3). In other configurations (e.g., Figure 10), the capillary openings may be closed at the second end (25), with open capillaries extending through the encapsulation at the first end (24).

[033] The permeate and concentrate are removed from the filtration element (3) through separate openings. In preferred embodiments with permeation from the outside in through hollow fibers, the permeate is removed Petition 870250041411, dated 05 / 20 / 2025, page 50 / 74 11 / 18 of open hollow fiber capillaries in the upper or lower part of the filter element (3). In filter elements adapted for inside-out permeation, the capillary openings are generally opened by encapsulations at both ends of the filter element, allowing the permeate to be removed from openings such as openings (33) of the annular collector (22), or other openings in the cylindrical housing (21).

[034] In the embodiments shown in Figures 5 and 5A, hollow fiber membranes (26) are encapsulated at one end within the collector (22). In this particular embodiment, the collector (22) includes an optional annular extension (32) that extends beyond the second end (25) of the cylindrical housing (21). As shown, the membranes (26) can be sealed within an encapsulation layer (31) that is located within the annular extension (32), extending through the encapsulation layer (31) and being in fluid communication with the collection chamber (10) by means of the optional end cap (23). In the embodiment shown in Figure 5, openings (33) are provided in the annular collector (22), between the encapsulation layer (31) and the second end (25) of the cylindrical housing (21), to remove the concentrate (in the preferred outside-in operating mode) or the permeate (in the less preferred inside-out configuration).In the embodiment shown in Figure 5A, the openings (33) for removing the permeate or concentrate from the filter element are provided by means of the cylindrical housing (21).

[035] In some embodiments, the hollow fiber membranes (26) are encapsulated within the surrounding section (30) of the annular collector (22) and / or within the cylindrical housing (21), with appropriately located openings below the encapsulation to remove the concentrate or permeate, as the case may be.

[036] The annular collector (22) may include annular extension (32) Petition 870250041411, dated 05 / 20 / 2025, page 51 / 74 12 / 18 even in cases where the membranes (26) do not extend to the annular collector (22) or beyond the surrounding section (30) of the annular collector (22). For example, the annular extension (32) can serve as a mounting region for the optional end cap (23).

[037] In locations radially aligned with thin regions (corresponding to relative minima in thickness of the surrounding section (30)), the annular extension (32) preferably has a transverse width that is not greater than the minimum width Wmin of the surrounding section (30) of the annular collector (22). Preferably, the annular extension (32) has a smaller transverse width, at all points around the circumference of the filtering element (3), than that of the surrounding section (30) of the annular collector (22). The annular extension (32) preferably has a circular outer perimeter with a diameter less than or equal to the minimum transverse width of the surrounding section (30) of the annular collector (22). Similarly, any end cap (23) preferably has a transverse width, at all points around the circumference of the filtering element (3), equal to or less than that of the surrounding section (30) of the annular collector (22).

[038] The optional end cap (23) is hollow and preferably includes at least one outlet (34) that is in fluid communication with both the annular collector (22) and the collection chamber (10), thus forming a fluid passage between them.

[039] The end cap (23) is preferably mounted in a removable manner on the annular collector (22), as this allows the end cap (23) to be removed from the annular collector (22) for, for example, cleaning and / or maintenance (e.g., sealing broken fibers). In the embodiment shown, the annular extension (32) of the annular collector (22) includes threading (36) on its outer surface. In such a case, reciprocal threading is provided on the corresponding inner surface of the Petition 870250041411, dated 05 / 20 / 2025, page 52 / 74 13 / 18 end cap (23). In another embodiment, the annular extension (32) includes threading (36) on its inner surface and reciprocal threading is provided on the corresponding outer surface of the end cap (23). Other mounting devices may be provided instead of or in addition to the threading, such as groove and ridge mounts, various types of snap-fit ​​mounts and the like.

[040] Multiple filtration elements (3) of the invention are arranged vertically within the casing (2) of the pressure vessel (1) to form a module pack. A module pack may contain, for example, 2 to 150 or more filtration elements (3), with 55 to 131 being a particularly useful number of elements for many applications. In other preferred embodiments, the number of filtration elements (3) within a module pack may be selected from 55, 61, 73, 85, 91, 97, 119 or 131.

[041] Figures 8 and 9 illustrate a suitable packing mode using preferred filter elements (3) having a cylindrical housing (21) and collector (22) in which the surrounding section (30) has the shape of a regular hexagon. As shown in Figure 8, adjacent filter elements (3) are aligned along one side of the surrounding sections (30) of their respective annular collectors (22). The aligned sides of the respective surrounding sections (30) of the annular collectors (22) are thinner regions (52) of the respective collectors. Thicker regions (53) reside within gaps (60) formed where two or more filter elements (3) join. This allows for the compaction of the filter elements (3), as the packing density is determined by the width Wmin of the surrounding section (30) of the annular collector (22). Thicker sections (53) provide mechanical strength to the annular collector (22).Note that a conventional collector with a circular cross-section typically has a constant width and thickness. Petition 870250041411, dated 05 / 20 / 2025, page 53 / 74 14 / 18 will need to be thicker than the thinnest section (52) to provide the necessary mechanical properties. This increased thickness increases the spacing between the elements and reduces the number of elements that can be packed within a given volume.

[042] Module packages comprising filtration elements of the invention typically have an irregular outer periphery, as shown in Figure 9. In some embodiments, the support plate (13) occupies part or all of the space between the irregular outer periphery of the module package and the housing (2), or otherwise provides resistance to flow between the irregular outer periphery of the module package and the housing (2). The support plate (13) may form a complete barrier to fluid flowing from top to bottom of the support plate (13), or it may be a partial barrier with openings that allow fluid to flow from top to bottom of the support plate only at specified locations and / or at specified rates. The support plate (13) or any part thereof may be inclined or otherwise adapted to promote fluid flow in a specific direction or directions, such as towards a concentrate port, such as the concentrate port (6) in Figure 1.In another embodiment, the support plate (13) occupies part or all of the space between the irregular outer periphery of the module package and the enclosure (2).

[043] Figure 8 illustrates another optional but preferred feature, namely, locking means for locking adjacent filter elements together. In the particular embodiment shown, the locking means includes clips (41) and receiving notches (40), which are adapted to receive and hold clips (41). Other mechanical locking means include a variety of latches and / or clips. Magnetic locking means are also useful. The locking means is preferably adapted to be opened and closed again to allow easy removal or unpacking. Petition 870250041411, dated 05 / 20 / 2025, pp. 54 / 74 15 / 18 of the filtering elements in the module package.

[044] The multi-element filtration apparatus (15) may also include various auxiliary apparatus, such as pumps, valves, seals, instrumentation, piping, ducts and the like, as desired or useful.

[045] The multi-element filtration apparatus of the invention is, in general, operable in the same manner as a conventional multi-element filtration apparatus. The feed fluid flow within a filtration element (3) can be driven upwards or downwards based on induced pressure differences. During the operation of a pressure vessel, as shown in Figure 1, for example, a feed fluid can be introduced into the pressure vessel (1) of the multi-element filtration apparatus (15) through the feed inlet port (4), and this alone could create an upward flow of feed fluid within the filtration element (3) if there were sufficient resistance to the feed fluid flow around the filtration elements (3). Such resistance can be provided, for example, by the tight positioning of adjacent modules with annular collectors.Alternatively, an upward movement of feed fluid within the filtration elements (3) can be created by air bubbles. Referring again to Figure 1, the mixing gas is supplied to the filtration element (3) by the aerator (11), and the bubbles used to keep the membranes (26) clean can also create an upward flow of feed fluid within the filtration element (3). The creation of an upward flow of feed fluid within the filtration elements (3) is desirable during operation, but it is also possible to create a downward flow of feed fluid by reversing the position of the inlet port (4) and the outlet port (6).

[046] Upon entering the inner portions of the filtration elements (3), the mixing gas and the feed fluid travel upwards through the Petition 870250041411, dated 05 / 20 / 2025, page 55 / 74 16 / 18 filtration elements (3), coming into contact with the filtration membranes (26), which separate the feed fluid into a permeate that passes through the membrane and a concentrate or reject that includes one or more concentrated materials that are rejected by the membrane and are therefore prevented from passing through it. The permeate and concentrate are removed separately from or near the second ends (25) of the filtration elements (3). In the preferred way of operating the multi-element filtration apparatus (15) of Figure 1, for example, the permeate is removed from the pressure vessel (1) through the permeate port (5). The concentrate is removed from the pressure vessel (1) through the concentrate port (6). The mixing gas can be vented through the concentrate port (6) or a separate air outlet (not shown).

[047] In the case of hollow fiber membranes operated with external-to-internal permeation, the mixing gas and feed fluid are supplied and placed in contact with the external surfaces of the hollow fiber membranes (26). A portion of the fluid passes through the hollow fiber membranes (26) and into their respective capillaries to produce the permeate, the concentrate in this case being that portion of the feed fluid and rejected materials that do not pass through and into the hollow fibers. The apparatus of the invention can also be operated internally, with the feed fluid being fed into the capillaries.

[048] In other embodiments, the multi-element filtration apparatus (15) is designed for and operated with top-down feed fluid flow, with the feed fluid being introduced above the filtration elements (3) and the concentrate and permeate being removed from the bottom of the filtration elements (3). The direction of feed fluid flow can be selected independently of whether the permeate is removed from the top or bottom of a filtration element (3).

[049] In Figure 10, an alternative embodiment of Petition 870250041411, dated 05 / 20 / 2025, pp. 56 / 74 The 17 / 18 multi-element filtration apparatus (115) includes the pressure vessel (101), which in the embodiment shown includes the casing (102) and the removable cover (109). Preferably, the casing (102) is cylindrical and the pressure vessel (101) is suitable for operation with internal pressures exceeding at least two bar above the external pressure. A filtration chamber (116) is surrounded by the casing (102) and the pressure plate (118). The filtration elements (103) are arranged vertically within the filtration chamber (116). In this embodiment, the filtration elements (103) are aligned by at least one of the positioner (108) and support plate (113). The positioner (108) may provide alignment, mechanical support and / or function as a flow restrictor to maintain the pressure drops required for operation.The support plate (113), as shown, includes openings to receive the filter elements (103) so that the collectors (122) rest on the support plate (113). In this embodiment, the filter elements are inverted compared to the embodiment of Figure 1, with the collectors (122) on the lower parts of the elements as installed.

[050] In operation, the feed fluid enters the pressure vessel (101) through the feed inlet (104) and enters the filtration elements (122) through the openings (133). As before, the optional aerator (111) provides gas bubbles that enter the openings (133) along with the feed fluid to provide buoyancy. The capillaries of the hollow fiber membranes in this particular embodiment are open at the bottom of the filtration elements (103) and closed at the top. In an outside-in operating mode, a portion of the feed fluid entering the openings (133) passes through pores in the hollow fibers to produce permeate within the capillaries. With the geometry of Figure 10, the permeate flows downwards, through the collector (122) and the optional end cap (123) to the collection chamber (110) and then out through the permeate port (105). Petition 870250041411, dated 05 / 20 / 2025, page 57 / 74 18 / 18 As before, the pressure plate (118) separates the filtration chamber (116) from the collection chamber (110), which is at a lower pressure than the filtration chamber (116). The concentrate is removed from the upper end of the filtration elements (103) through the holes (150). In the particular embodiment shown, the concentrate exiting the holes (150) enters the filtration chamber (116) and is removed from the pressure vessel (101) through the concentrate port (106).

[051] The multi-element filtration apparatus of the invention is useful for filtering a wide variety of fluids, especially aqueous fluids, such as groundwater, surface water, seawater, process streams from chemical operations and / or power generation stations, as well as many others. In a particular embodiment, the multi-element filtration apparatus is an ultrafiltration and / or microfiltration apparatus for seawater, and can be used, for example, as a pre-filter to prepare seawater for reverse osmosis to produce potable water.

[052] Although the present invention has been described in terms of specific exemplary embodiments, it will be appreciated that various modifications and alterations may be made by those skilled in the art without departing from the sense and scope of the invention, as set forth in the following claims. Petition 870250041411, dated 05 / 20 / 2025, pp. 58 / 74

Claims

1 / 4 Claims 1.FILTER ELEMENT, characterized by comprising: a) a cylindrical housing having an outer diameter, the cylindrical housing surrounding an inner portion of the filter element, the cylindrical housing having first and second opposite ends; b) at least one filter membrane disposed within the inner portion of the filter element; c) one or more openings for admitting a feed fluid through at least one of the first and second opposite ends of the cylindrical housing and into the inner portion of the filter element; d) an annular collector including a surrounding section that encircles one of the opposite ends of the cylindrical housing, the surrounding section having a periodically varying transverse width and thickness such that the surrounding section of the annular collector has alternating thinner and thicker regions; and e) separate openings for removing the permeate and concentrate from the filter element.

2. FILTERING ELEMENT, according to claim 1, characterized in that the thickness of the surrounding section of the annular collector varies periodically to produce relative minima at regular intervals of 30 to 120 degrees.

3. FILTERING ELEMENT, according to claim 2, characterized in that the thickness of the surrounding section of the annular collector varies periodically to produce relative minima at repeating intervals of 60 degrees.

4. FILTERING ELEMENT, according to any one of claims 1 to 3, characterized by the annular collector section surrounding Petition 870250041411, dated 05 / 20 / 2025, page 59 / 74 2 / 4 the outlet of the cylindrical housing having six flat outer faces arranged regularly around the circumference of the section with vertices between each pair of adjacent flat outer faces, the vertices being optionally curved or chamfered.

5. FILTERING ELEMENT, according to claim 4, characterized in that the annular collector section surrounding the outlet of the cylindrical housing has a regular hexagonal cross-section.

6. FILTRATION ELEMENT, according to any one of claims 1 to 5, characterized by having at least one filtration membrane extending into the annular collector and being encapsulated within the annular collector.

7. FILTRATION ELEMENT, according to claim 6, characterized by having at least one filtration membrane extending through the encapsulation and being in fluid communication with a fluid collection region external to both the cylindrical housing and the annular collector to receive the permeate.

8. FILTRATION ELEMENT, according to claim 7, characterized in that the annular collector further comprises an annular extension that extends beyond the encircled end of the cylindrical housing, at least one filtration membrane is encapsulated within the annular extension, and the annular collector has openings between the encapsulation and the end of the cylindrical housing for removing the concentrate from the annular collector.

9. FILTERING ELEMENT, according to claim 8, characterized in that the annular extension has a circular outer perimeter with a diameter less than or equal to the minimum cross-sectional width of the surrounding section of the annular collector.

10. FILTERING ELEMENT, according to any of claims 8 to 9, as per Petition 870250041411, dated 05 / 20 / 2025, page 60 / 74 3 / 4, characterized by further comprising an end cap affixed to and in fluid communication with both the annular collector and the fluid collection region.

11. FILTERING ELEMENT, according to claim 10, characterized in that the end cap is removablely attached to the annular extension of the annular collector.

12. MULTI-ELEMENT FILTRATION APPARATUS, the apparatus characterized by comprising: a) a pressure vessel having an enclosure; b) multiple filtration elements, as defined in any one of claims 1 to 11, arranged vertically within the pressure vessel enclosure, wherein adjacent filtration elements are aligned along thinner regions of the surrounding sections of the annular collectors of adjacent filtration elements; a feed inlet port for introducing a feed fluid into the pressure vessel; a permeate discharge port for discharging permeate produced by the multiple filtration elements from the pressure vessel; and a concentrate discharge port for discharging concentrate produced by the multiple filtration elements from the pressure vessel.

13. MULTI-ELEMENT FILTRATION APPARATUS, according to claim 12, characterized in that the multiple filtration elements are mounted in a removable manner on the support.

14. MULTI-ELEMENT FILTRATION APPARATUS, according to claim 13, characterized in that the support comprises a support plate within the pressure vessel, the support plate having openings to receive filtration elements, and the annular collectors rest on and are supported by the support plate. Petition 870250041411, dated 20 / 05 / 2025, pp. 61 / 74 4 / 4 15. MULTI-ELEMENT FILTRATION APPARATUS, according to any one of claims 12 to 14, characterized by further comprising one or more aerators for supplying a mixing gas to the multiple filtration elements.

16. MULTI-ELEMENT FILTRATION APPARATUS, according to any one of claims 12 to 15, characterized in that the concentrate discharge port is located above the annular collectors of the filtration elements.

17. MULTI-ELEMENT FILTRATION APPARATUS, according to any one of claims 12 to 16, characterized in that the multiple filtration elements form a package of modules having an irregular outer periphery.

18. MULTI-ELEMENT APPARATUS, according to claim 17, characterized in that the annular collectors rest on and are supported by a support plate, and the support plate provides resistance to flow between the irregular outer periphery of the module package and the housing.

19. MULTI-ELEMENT FILTRATION APPARATUS, according to any one of claims 12 to 18, characterized by further comprising locking means for locking adjacent filtration elements together. Petition 870250041411, dated 20 / 05 / 2025, pp. 62 / 74

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