WO1999019043A2

WO1999019043A2 - Filter elements and methods for making filter elements

Info

Publication number: WO1999019043A2
Application number: PCT/US1998/021229
Authority: WO
Inventors: Robert S. Gieger; Jeffrey Canil; Stephen J. A. Maybee; James T. Connors; Joseph Peri; Joseph Kosalek; Alan R. Rausch
Original assignee: Pall Corporation
Priority date: 1997-10-09
Filing date: 1998-10-09
Publication date: 1999-04-22
Also published as: WO1999019043A3

Abstract

The filter element includes a filter medium and filter hardware. The filter and/or the filter hardware may be made of materials that can be easily disposed of, such as incinerable materials and/or materials that are easy to chop, shred or compact. The filter element may include one or more parts that facilitate standardization, such as a filter support having a number of modular segments and/or an end cap assembly having a number of end pieces. The filter element may also have an increased filtration capacity.

Description

FILTER ELEMENTS AND METHODS FOR MAKING FILTER ELEMENTS

This application claims the priority of U.S. provisional patent application 60/061,458, filed October 9, 1997, and U.S. provisional patent application 60/065,800, filed November 14, 1997, which applications are incorporated by reference in their entirety.

FIELD OF THE INVENTION

This invention relates to filter elements and methods for making filter elements which may be used in a variety of applications, including, for example, in nuclear power generation systems.

BACKGROUND OF THE INVENTION

There are a number of challenges facing the manufacturers and users of filter elements.

For example, because filter elements may become contaminated during use, the disposal of contaminated filter elements is a challenge facing filter users as well as manufacturers. This is especially true in the nuclear power industry where spent filter elements are often radioactive. An effective method of reducing the volume of radioactive waste is to incinerate spent filter elements. Another method is to chop or shred spent filter elements into small pieces, or to compact spent filter elements, before disposal. This method is especially useful if the spent filter elements are too radioactive for incineration. However, some of the materials presently used to fabricate filter elements, such as metals, are not sufficiently incinerable and are difficult to chop, shred or compact. Therefore, there is a need in the nuclear industry for filter elements that use more incinerable materials or materials that are easy to chop, shred or compact. Further, many filtration processes in a nuclear power generation system involve exposure to radiation and/or to corrosive chemicals at relatively high temperatures and pressures, both during normal operation and in the event of an accident. In addition, robotic systems are typically used to install and remove these filter elements, increasing the risk of mishandling the filter elements, e.g., by crushing, striking or dropping them. Thus, filter elements preferably can perform reliably under those conditions.

Finally, filter manufacturers are in a constant effort to reduce costs. Filter manufacturers make a variety of filter elements, some in relatively small quantities, because in the nuclear power industry, for example, existing nuclear power generation systems use many different types of filter elements. The manufacturing of many different types of filter elements in small quantities increases the cost of design, testing and production, and causes a proliferation of inventoried components. Thus there is a need in the industry to reduce the costs related to inventory control and the manufacturing of many different types of filter elements.

SUMMARY OF THE INVENTION

A filter element according to one aspect of the invention includes a filter medium and at least a first perforated filter support that is cooperatively arranged with the filter medium. The perforated filter support includes a plurality of modular segments that are attached to one another.

A method of assembling a filter element according to another aspect of the invention includes assembling a perforated filter support from a plurality of modular segments and disposing the perforated filter support adjacent to a filter medium. A filter element according to still another aspect of the invention includes a filter medium having first and second ends and first and second end cap assemblies at the first and second ends of the filter medium, respectively. The first end cap assembly includes at least first and second end pieces, each having first and second opposite sides. The second side of the first end piece opposes the first side of the second end piece. A method of assembling a filter element according to yet another aspect of the invention includes assembling a filter end cap assembly by connecting a first end piece with a second end piece with the first side of the second end piece facing the second side of the first end piece, and bonding the first side of the first end piece to an end of a filter medium. The above four aspects of the invention facilitate the use of standard parts, i.e., parts that can be used by different types of filter elements. The use of standard parts is an effective way to reduce the cost of filter elements because, even though certain filter elements may be sold in small quantities, some of their parts (the standard parts) can nevertheless be made in large quantities. Parts made in large quantities tend to have lower costs because they can be more efficiently produced and because the per-unit fixed cost is lower if more parts are produced. (Fixed costs are the costs that occur regardless how many units are produced.) Consequently, filter elements that use more standard parts generally cost less. Furthermore, the standardization of parts can facilitate inventory control and reduce product development time because only the nonstandard parts need to be designed, tested and produced.

A filter element according to a further aspect of the invention includes a filter medium having a first end surface, and a first end cap attached to the first end surface of the filter medium. The filter element is adapted to be installed in a filter housing having a first housing seal ring. The first housing seal ring has a known thickness and includes a filter aperture having a ledge. The first end cap has a height less than the thickness of the first housing seal ring and includes a rim having a seal tucked over the rim. Thus, when the filter element is installed into the filter aperture and the seal rests on the ledge, the filter element extends into the filter aperture.

An advantage of the filter element according to this aspect of the invention is the increased filtration capacity of the filter medium. This is so because the height of the end cap in the filter element can be substantially less than the thickness of a first housing seal ring of a filter housing. Hence, a longer filter medium can be used in the filter element and one that can extend into the first housing seal ring. The longer filter medium enhances the filtration capacity of the filter element because filtration can take place at the interface formed by the filter element and the first housing seal ring.

A filter element according to a still further aspect of the invention includes a filter medium and filter hardware. The filter medium and/or the filter hardware are fabricated from materials which are incinerable and/or easy to chop, shred or compact and yet have the radiation resistance, temperature tolerance, tensile strength, and/or filtration capacity to allow the filter element to filter fluids within an environment such as a nuclear power generating system.

In some filter elements embodying this aspect of the invention, the filter medium may preferably be fabricated from an incinerable polymeric filter material, including aromatic polyamide, polypropylene or polyester. An aromatic polyamide filter medium provides the filter element with micron to sub-micron filtration capacity and a polypropylene filter medium provides the filter element with micron filtration capacity. Alternatively, the filter medium may preferably be fabricated from glass fiber materials that are easy to chop, shred or compact. A glass fiber filter medium provides the filter element with sub-micron filtration capacity.

The filter hardware may preferably be fabricated from an incinerable polymer such as PBT, polyetherimide, polyetheretherketone, polyester, or polypropylene. Filter hardware made of these materials has a high tensile strength that provides the filter element with excellent support during filtration and also protects the filter element from accidental abuse during insertion and removal. Alternatively, the filter hardware may be fabricated from glass-filled materials, for example, glass-filled acetal resin or glass-filled polymer, such as glass filed polypropylene or glass-filled polyester, which materials are easy to chop, shred or compact.

A filter element using the incinerable materials mentioned above has a number of advantages. For example, when it is spent, the filter element may be relatively easily disposed of by incineration, and when incinerated, the filter element can meet commercial incinerator emission standards. Alternatively, a filter element using glass fibers and glass- filled materials may be chopped, shredded or compacted before disposal to reduce its volume, which may significantly reduce the cost of the disposal of radioactive waste. Additionally, the filter element materials are relatively easy to fashion and are relatively inexpensive. Other advantages of this invention will become apparent from the detailed description that follows. It should be understood, however, that the detailed description and specific embodiments are provided for illustration only since various additions and modifications within the spirit of the invention will become apparent to those skilled in the art from this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a cross sectional view of a filter housing which may be used, for example, in a nuclear power generation system.

Figure 2 is a cross sectional view of a filter element according to the present invention.

Figure 3a is a cross sectional view of a modular filter support segment according to the present invention.

Figure 3b is an elevation view of a modular filter support segment according to the present invention. Figure 4 is an elevation view of a perforated filter support according to the present invention, which filter support comprises a plurality of modular segments shown in Figure 3. Figure 5 is a perspective view of a perforated filter support according to the present invention, which filter support comprises a plurality of modular segments.

Figure 6 is a cross sectional view of a filter element according to the present invention. Figure 7 is a top plan view of a filter element.

Figure 8 is a cross sectional view of a filter element according to the present invention, which filter element is disposed in a filter housing that may be used, for example, in a nuclear power generation system.

Figure 9 is a cross sectional view of a filter element according to the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Filter elements embodying one or more aspects of the invention may be contained in a wide variety of filter housings. For example, a filter housing may contain two or more filter elements supported, e.g., by a tube sheet disposed inside the filter housing.

Alternatively, a filter housing may contain only a single filter element. In a nuclear power generation system, for example, a single filter element may be disposed in a filter housing 10, 20 as shown in Figure 1 or 8. The filter housing 10 shown in Figure 1, for example, may include a hollow, cylindrical member 11 with a first end 12 and a second end 13, an inlet 14, an outlet 15 and a cover 16. The filter element may be inserted into the housing 10 through the open first end 12 and secured in the housing 10 by the cover 16, which may be attached to the cylindrical member 11 in any suitable manner, e.g., by bolts. The first end 12 of the cylindrical member 11 may include a ledge 17 upon which the filter element rests. Pressurized fluid may be introduced axially into the filter element through the inlet 14, for example, an opening on the second end 13 of the cylindrical member 11, passed radially inside-out through the filter element and discharged from the housing 10 through the outlet 15, for example, an opening on the side of the cylindrical member 11. Alternatively, the pressurized fluid may be directed outside-in through the filter element and/or through an inlet and an outlet on opposite ends or on the same end of filter housing 10. As shown in Figure 2, one example of a filter element 100 embodying one or more aspects of the invention preferably includes a filter medium 102 and at least a first perforated filter support 104 cooperatively arranged with the filter medium 102. The illustrated filter element 100 may further include first and second end caps 106, 108, between which the filter medium 102 and the filter support 104 are disposed, a crud trap 110, and one or more tie rods 112 extending between the end caps 106, 108.

The filter medium 102 preferably has a hollow cylindrical configuration with first and second ends. The filter medium 102 may include any suitable separation medium that may have any suitable pore size distribution or removal rating. The filter medium 102 may include a self-supporting fibrous mass, a fibrous sheet or a porous membrane, which is wound or pleated and formed into a cylindrical configuration. Preferably, the filter medium 102 comprises a pleated composite, such as those disclosed in U.S. Patent No. 5,543,047 or International Publication No. WO97/24169, both of which are incorporated by reference. The first end cap 106 has first and second opposite sides 120, 122. The first end cap

106 may be a blind end cap as shown in Figure 2. Alternatively, the first end cap may have an opening, such as the opening 124 at the center of the end cap shown in Figure 7, which is a top view of a filter element. The opening 124 allows pressurized liquid to contact both sides of the first end cap 106, allowing the forces acting on the sides 120, 122 of the first end cap 106 to cancel each other and reducing the stress on the first end cap 106. The filter element 100 may include a lifting arrangement such as a handle 126, as shown in Figure 7, which facilitates the insertion or removal of the filter element into or out of filter housing 10. Preferably the lifting arrangement is on the first end cap. The lifting arrangement preferably is configured to ensure that the filter element moves through the housing 10 without binding during insertion and removal. For example, the handle may have an inverted V-shape or only the bottom side of the handle may have an inverted V-shape. When a lifting device such as a hook engages the handle to lift the filter element, the lifting device automatically slides to the middle of the handle, which ensures that the filter element remains axially aligned with the housing 10 during insertion and removal. The lifting arrangement may be a unitary part of the first end cap or a separate, attachable piece.

The first side 120 of the first end cap 106 may be sealingly attached to one end of the filter medium 102. The attachment may be accomplished by any suitable means which provides a strong, uniform seal, including melt, spin or sonic welding, polycapping, or thermal, adhesive or solvent bonding. The first end cap 106 may include a seal arrangement, such as a slit O-ring seal or a dovetail notch face seal, which prevents pressurized fluid from bypassing the filter medium 102 or from escaping to the outside of the filter housing 10. For example, in the embodiment illustrated in Figure 2, the second side 122 of the first end cap 106 may include an annular extension 128, preferably radially outward, defining an outer rim. A slit O-ring seal 130 may be tucked over the annular extension 128. If the filter element 100 is installed in the filter housing 10, the combination of the annular extension 128 and the slit O-ring seal 130 may sit on the ledge 17 in the cylindrical member 11 of the filter housing 10. When the housing cover 16 is in the closed position, the slit O-ring seal 130 forms a face seal with the ledge 17 and the housing cover 16, preventing fluid from bypassing the filter medium 102 or from escaping to the outside of the filter housing 10. Alternatively, the first end cap may not have the slit O-ring seal but may include an O-ring seal disposed in a groove on the side surface of the first end cap and another O-ring seal disposed in a groove on the second side surface of the first end cap. The two O-ring seals may prevent fluid from bypassing the filter medium or from escaping to the outside of the filter housing 10.

The second end cap 108 may also have first and second opposite sides 134, 136 and may also be an open end cap with an annular opening 132. The opening 130 may serve as an outlet or, preferably, an inlet to the filter element 100. The first side 134 of the second end cap 108 may be sealingly attached to the other end of the filter medium 102. The attachment may also be accomplished by any suitable means which preferably provides a strong, uniform seal, including melt, spin or sonic welding, polycapping or thermal, adhesive or solvent bonding.

The crud trap is used to collect loose crud contained in the filtered fluid and helps to prevent the crud from falling into the filter housing during operation or during removal of loaded filter element at time of change out. The crud trap may be constructed in a number of ways. For example, as shown in Figure 2, the first side 134 of the second end cap 108 may include a cylindrical extension 138 around its inner rim. The outer sidewall of the cylindrical extension 138 preferably has a diameter smaller than the diameter of the inner sidewall of the filter medium 102. A crud trap 110 may then be formed by the outer sidewall of the cylindrical extension 138, the first side 134 of the second end cap 108, and the inner sidewall of the filter medium 102. This crud trap 110 may be used to collect loose crud that may settle out of fluid flowing from the inside to the outside of the filter element 100 and that may fall off the filter medium during its removal at time of change out. The cylindrical extension 138 may be attached to the second end cap 108 by any suitable means, including welding or bonding. Preferably, the cylindrical extension 138 and the second end cap 108 are formed as a unitary part for enhanced strength. The second end cap 108 may also include a seal to prevent the fluid from bypassing the filter medium 102 around the second end cap 108. For example, the seal may be an O- ring seal located either at the inner sidewall or the outer sidewall of the second end cap 108. In the embodiment illustrated in Figure 2, for example, an O-ring seal 142 is disposed within a circumferential groove 140 on the outer sidewall of the second end cap 108. When the filter element 100 is installed in the filter housing 10, the O-ring seal 142 preferably forms a piston seal with the inner surface of the cylindrical member 11 of the filter housing 10, preventing bypass of the pressurized fluid around the filter medium 102.

The filter element 100 may be secured by any suitable means, such as welding and the use of tie rods. For example, as shown in Figure 2, one or more tie rods 112, preferably equally circumferentially spaced, may extend between the first and second end caps 106, 108 to secure the filter element 100 and/or to transfer lifting forces from the first end cap 106 to the second end cap 108. The first and second end caps 106, 108 may each have one or more through holes 144, 146. A tie rod 112 may extend through one through hole in one of the end caps 106, 108 and through a through hole in the other end cap 106, 108. The tie rod 112 may then be fastened to secure the filter element. The second sides 122, 136 of the first and second end caps 106, 108 may each include an annular indentation, or one or more recesses (not shown), to accommodate the nuts 148. Preferably, the depth of each indentation or the recess is equal to or greater than the height of each nut 148 so that the tie rods 112 do not extend beyond the second sides 122, 136 of the end caps 106, 108 and the filter element 100 can be installed in the filter housing 10. One with ordinary skill in the art would appreciate that there are a number of tie rod configurations that can be used to secure the filter element 100. For example, a nut may be formed at the first end of a tie rod and another nut may be threaded to the second end of the tie rod. Alternatively, the second end may be threaded into one of the first and second end caps. In addition, the tie rods may extend between the first and second end caps outside the filter element 100, even though in Figure 2 they extend between the end caps 106, 108 inside the filter element 100.

The perforated filter support 104 may be variously configured. For example, the filter support 104 may be a unitary part or, as shown in Figure 2, may preferably include two or more modular segments. Each modular segment may be a hollow, perforated cylindrical segment 114 as shown in Figures 3 a and 3b. The filter support 104 may then include a plurality of the cylindrical modular segments 114 attached axially. In Figure 4, the modular segments 114 are attached to each other with an interlocking mechanism, although they may be attached by any suitable means, such as welding or bonding.

The interlocking mechanism may be of any suitable configuration that provides sufficient attachment in the axial, radial and/or theta (rotational) directions between the modular segments 114. Figures 3 and 4 illustrate a preferred interlocking mechanism. In Figures 3 a and 3b, a cylindrical modular segment 114 may include a plurality of detents 116 (and/or apertures) disposed at a first axial end and a plurality of complementary apertures 118 (and/or detents) disposed at an opposite second axial end. The detents 116 (and/or apertures) at the first end of a first modular segment 114 can be inserted into and secured to the complementary apertures 118 (and/or detents) at the second end of a second modular segment 114, attaching the two modular segments 114. Any number of such modular segments 114 can be assembled in this manner to form a filter support 104. Alternatively, a cylindrical modular segment may include tongues and/or grooves at a first axial end and complementary grooves and/or tongues at an opposite second axial end. Two modular segments may be attached to each other with the tongues and/or grooves at the first end of the first segment disposed in the complementary grooves and/or tongues at the second end of the second segment. The two segments can be locked together by axially compressing them, by twisting them with respect to each other, to engage the interlocking mechanism.

Alternatively, the cylindrical modular segments may include opposite first and second axial end regions, with the inner diameter of the first end region equal to or slightly larger than the outer diameter of the second end region. As a result, the first end region of a first modular segment can slide telescopically over the second end region of a second modular segment, attaching the two modular segments to each other using, for example, detents and apertures as previously described.

The one or more tie rods 112 (or any other securing means such as bonding or welding the modular segments together) may help ensure that the modular segments remain locked together during filtration and during insertion and removal of the filter element. In some filter supports embodying the invention (not shown), the interlocking mechanism may only resist forces compressing the modular segments and prevent relative radial and/or theta (rotational) movement between two modular segments, but may not prevent two modular segments from be separated from each other in the axial direction. However, the tie rods may hold the modular segments together axially when the filter element is assembled.

Once the completed modular segments 114 are coaxially assembled into the filter support 104, the filter support 104 may be attached to the end caps 106, 108, for example, in the same manner as the filter medium 102 is attached to the end caps 106, 108. The filter medium 102 and the filter support 104 may be attached to the end caps 106, 108 as a single unit or they can be attached to the end caps 106, 108 separately. To enhance the strength of the attachment between the filter support 104 and the end caps 106, 108, the axial ends of the filter support 104 adjacent to the end caps preferably do not have any configuration, such as detents, perforations or tapers, which may weaken the attachment. Accordingly, at each of its two ends, the filter support 104 may have a segment which has a continuous band at the end which may be attached to an end cap.

While the modular segment 114 shown in Figures 3 a and 3b is a cylindrical segment 114, the modular segment may be configured in a wide variety of other ways. For example, each modular segment may be a generally rectangular perforated strip having an attachment region such as an interlocking mechanism along at least two opposite, and preferably all four, edges. A cylindrical support segment may be formed by attaching two opposite axially-extending edges of the rectangular strip by any suitable means, such as welding, thermal, bonding or interlocking mechanisms. The resulting cylindrical segments may then be attached as previously described. This method of configuring the modular segments is advantageous because rectangular strips are easier to manufacture and require less storage space.

Alternatively, a cylindrical perforated filter support 115 (or a cylindrical filter support segment 114) may include one or more circumferentially arranged flat or curved rectangular modular segments 117 as shown in Figure 5. The rectangular modular segments 117 may each have first and second opposite axially-extending edges 119, 121, each edge 119, 121 including an attachment region. The first edge 119 of the first rectangular modular segment 117 may be attached to the second edge 121 of the second rectangular modular segment 117, and the first edge 119 of the second rectangular modular segment 117 may be attached to the second edge 121 of the third rectangular modular segment 117, and so forth. Finally, the first edge 119 of the last rectangular modular segment 117 may be attached to the second edge 121 of the first rectangular modular segment 117. The plurality of rectangular modular segments 117 can be attached by any suitable means, such as welding, bonding, or interlocking mechanisms. In Figure 5, for example, the filter support segments are attached to one another by the means of bonding.

To increase the flexibility of the modular approach, a filter element may include two or more standard modular segments of similar or different sizes. For example, a filter support may include two or more standard cylindrical modular segments of similar or different heights. Or a filter support (or a cylindrical modular segment) may include two or more rectangular modular segments of similar or different widths. The use of standard modular segments of different sizes greatly increases the number of filter support sizes that can be assembled from the modular segments.

The perforated filter support may be a cage disposed adjacent to the outer periphery of the filter medium 102 for supporting the filter medium 102 against outwardly radial forces. Alternatively, the perforated filter support may be a core disposed adjacent to the inner periphery of the filter medium for supporting the filter medium against inwardly radial forces. The filter element may also include a second perforated filter support (not shown) that has a different diameter. The first and second filter supports may be a cage and a core, respectively, which are concentrically arranged with the filter medium 102. The cage and the core support the filter medium 102 against outwardly and inwardly radial forces, respectively. Lower cost, flexibility, and inventory control are some of the reasons for assembling a filter support from a plurality of standard modular segments. Presently, nuclear filter elements have several different lengths, typically 10, 20, or 30 inches, and have rather large diameters, typically 2.75, 6.00, or 12.00 inches. Each type of filter support requires a different mold, and a mold for a unitary filter support with a large diameter or a long length is expensive. In contrast, a mold for a modular filter support segment, which may be either a short cylinder or a strip, is substantially less expensive, and one mold may be used for filter supports of different diameters and/or lengths. For example, the filter supports for many or all of the currently used nuclear filter elements may be assembled from a number of standard segments made with one mold. In addition, the use of standard segments may simplify the inventory requirements because only the standard segments, rather than a number of unitary filter supports of different lengths and/or diameters, need to be inventoried.

The filter element 100 may be made of any suitable materials. Preferably most or all of the components of the filter element 100 are fabricated from incinerable materials or materials that can be easily chopped, shredded or compacted. Further, the materials preferably have the necessary radiation resistance, temperature tolerance, tensile strength, differential pressure capability, and filtration capacity to allow the filter element to filter fluids under adverse conditions, such as the conditions within a conventional nuclear power generating system. In particular, the filter hardware, i.e., components separate from the filter medium such as the end caps, the tie rods, and the perforated filter support, may be formed from high strength, incinerable polymeric materials. Preferably, the filter hardware is fabricated from a polymer such as PBT, polyetherimide, polyetheretherketone, polyester, or polypropylene. The polymers are preferably highly temperature and radiation resistant, and have high tensile strength which allows the resulting filter hardware to withstand radial and axial forces during filtration and accidental abuse during insertion and removal. They are also preferably relatively inexpensive and easy to fashion, using methods such as injection molding. The filter medium may also be fabricated from incinerable materials, preferably from a polymeric filter medium, more preferably from aromatic polyamide, polypropylene or polyester. Aromatic polyamide and polypropylene both have at least micron level removal ratings, high temperature tolerance, high differential pressure capability, and high radiation resistance. An aromatic polyamide filter medium may have sub micron removal ratings. Collectively, polyetherimide, aromatic polyamide, polyetheretherketone, polyester and polypropylene are completely incinerable and, when incinerated, can meet all incinerator and emission standards. Consequently, when spent, a filter element made of these materials can be completely incinerated while meeting all incinerator and emission standards. Moreover, polyetherimide, aromatic polyamide, polyetheretherketone, polypropylene, polyester, glass filled materials and glass fibers are easy to fashion and relatively inexpensive. Hence, the filter elements according to the present invention enables many applications which were economically or structurally impractical for previous filter elements.

A preferred combination for the filter element according to the present invention is an aromatic polyamide filter medium and a polyetherimide filter hardware. The aromatic polyamide filter medium has micron to sub micron filtration capacity, an ability to filter high temperature liquids, and hence can be used in, for example, either the primary or the secondary loop of a nuclear power generating system. The polyetherimide filter hardware can be fabricated by injection molding polyetherimide such as that available under the trade designation ULTEM 1010, ULTEM 2100, or ULTEM 2300, all owned by the General Electric Corporation. Another preferred material for filter hardware is polyester.

Alternatively, the filter hardware may be fabricated from any glass-filled material that can be easily chopped, shredded or compacted, where chopping, shredding or compacting is the preferred method of volume reduction. However, the preferred glass-filed material for filter hardware is glass-filled polypropylene. Glass-filled materials, which have much higher strength than regular materials, may include, for example, glass-filled acetal resin or glass-filled polymer, such as glass filed polypropylene or glass-filled polyester s . Further, the filter medium may be fabricated from materials, such as glass fiber, that can be easily chopped, shredded or compacted.

Figure 6 illustrates another filter element 200 embodying the invention. The filter element 200 includes a filter medium 202 having first and second ends and first and second end cap assemblies 250, 252 between which the filter medium 202 is disposed. The filter element 200 may also include a first perforated filter support 204 cooperatively arranged with the filter medium 202, a crud trap 210 and one or more tie rods 212 (or any other suitable means, such as welding) extending between the end cap assemblies 250, 252 to secure the filter element 200.

The filter element 200 may include any or all of the patent features discussed with respect to the filter element 100. For example, the filter medium 202, the perforated filter support 204, and the tie rods 212 of the filter element 200 may be the same as or similar to their counterparts 102, 104, 112 in the filter element 100 shown in Figure 2, in terms of both materials and constructions.

Preferably, at least one of the end cap assemblies, e.g., the first end cap assembly, includes at least first and second end pieces. For example, as shown in Figure 6, the first end cap assembly 250 includes at least first and second end pieces 254, 256, each having first and second opposite sides 258, 260, 262, 264.

The first end piece 254 of the first end cap assembly 250 may be generally annular and may have a circular opening 266 at its center. The first side 258 of the first end piece 254 is preferably sealingly attached to one end of the filter medium 202. The attachment may be accomplished by any suitable means which provides a strong, uniform seal, including melt, spin or sonic welding, polycapping, or thermal, adhesive or solvent bonding.

The first end piece 254 of the first end cap assembly 250 may be connected to the second end piece 256 with the second side 260 of the first end piece 254 opposing the first side 262 of the second piece 256. Preferably the second side 260 of the first end piece 254 is sealingly connected to the first side 262 of the second piece 256, and the connection limits or prevents relative radial and/or theta (rotational) movement between the first and second end pieces 254, 256. For example, as shown in Figure 6, there may be a generally annular tongue 268 on the second side 260 of the first end piece 254 and a generally annular groove 272 on the first side 262 of the second end piece 256, or vice versa. The annular tongue 268 may be used to accommodate the annular groove 272, and the tongue-groove arrangement limits or prevents relative radial and/or theta (rotational) movement between the first and second end pieces 254, 256. A seal such as an O-ring seal or a gasket seal may be placed between the end pieces 254, 256 to prevent leakage at the interface of the end pieces 254, 256. In a preferred embodiment, the seal may comprise a coating of a sealant such as an RTV silicone, applied, for example, at the tongue and groove. Alternatively, the second side 260 of the first end piece 254 and the first side 262 of the second piece 256 may comprise flat surfaces and/or grooved surfaces, and they may be sealingly bonded or welded to each other. The bonding or welding prevents relative radial and/or theta (rotational) movement between the first and second end pieces 254, 256.

Similar to the first end cap 106 shown in Figure 2, the second end piece 256 may also include a seal arrangement, such as a slit O-ring seal or a dovetail notch face seal, which prevents pressurized fluid from bypassing the filter medium 202 or from escaping to the outside of the filter housing 10. For example, in the embodiment illustrated in Figure 6, the second side 264 of the second end piece 256 may include an annular extension 228, preferably radially outward, defining an outer rim. A slit O-ring seal 230 may be tucked over the annular extension 228. If the filter element 200 is installed in the filter housing 10, the combination of the annular extension 228 and the slit O-ring seal 230 may sit on the ledge 17 in the cylindrical member 11 of the filter housing 10. When the housing cover 16 is in the closed position, the slit O-ring seal 230 forms a face seal with the ledge 17 and the housing cover 16, preventing the pressurized fluid from bypassing the filter medium 202 or from escaping to the outside of the filter housing 10.

The second end piece 256 may also have an opening 270 at its center as shown in Figures 6 and 7. The opening 270 is preferably smaller than the opening 266 of the first end piece 254 so that the tie rods 212 may be attached to the second end piece 256 though the opening 266 in the first end piece 254. The openings 266, 270 on the first and second end pieces 254, 256 allow pressurized liquid to contact both sides of the first end cap assembly 250, allowing the forces acting on the sides of the first end cap assembly 250 to cancel each other and reducing the stress on the first end cap assembly 250.

The filter element 200 may include a lifting arrangement such as a handle 226, as shown in Figure 7, which facilitates the insertion or removal of the filter element into or out of filter housing 10. Preferably the lifting arrangement is on the second end piece of the first end cap assembly. The lifting arrangement preferably is configured to ensure that the filter element moves through the housing without binding during insertion and removal. For example, the handle may have an inverted V-shape or only the bottom side of the handle may have an inverted V-shape. When a lifting device such as a hook engages the handle to lift the filter element, the lifting device automatically slides to the middle of the handle, which ensures that the filter element remains axially aligned with the housing during insertion and removal. The lifting arrangement may be a unitary part of the second end piece 256 or a separate, attachable piece.

The second end cap assembly preferably also includes at least first and second end pieces. For example, in the embodiment illustrated in Figure 6, the second end cap assembly 252 preferably includes at least first and second end pieces 274, 276, each having first and second opposite sides 278, 280, 282, 284. Similar to the first end piece 274 of the first end cap assembly 250, the first end piece 274 of the second end cap assembly 252 may be generally annular with a circular opening 286 at its center. The second end piece 276 of the second end cap assembly 252 also has an opening 290 at its center. This opening 290 together with the opening 286 in the first end piece 274 may serve as an outlet or, preferably, an inlet to the filter element. The opening 290 is preferably smaller than the opening 286 on the first end piece 274 so that the tie rods 212 may be attached to the second end piece 276 though the opening 286 on the first end piece 274. The first side 278 of the first end piece 274 of the second end cap assembly 252 may be sealingly attached to the other end of the filter medium 202. The attachment may be accomplished by any suitable means which provides a strong, uniform seal, including melt, spin or sonic welding, polycapping, or thermal, adhesive or solvent bonding.

The first end piece 274 may be connected to the second end piece 276 with the second side 280 of the first end piece 274 opposing the first side 282 of the second piece 276. Preferably the second side 280 of the first end piece 274 is sealingly connected to the first side 282 of the second piece 276, and the connection limits or prevents relative radial and/or theta (rotational) movement between the first and second end pieces 274, 276. For example, as shown in Figure 6, there may be a generally annular tongue 288 on the second side 280 of the first end piece 274 and a generally annular groove 292 on the first side 282 of the second end piece 276. The annular tongue 288 may be used to accommodate the annular groove 292, and the tongue-groove arrangement limits or prevents relative radial and/or theta (rotational) movement between the first and second end pieces 274, 276. A seal such as an O-ring seal or a gasket seal may be mounted between the first and second end pieces. In a preferred embodiment, the seal may comprise a coating of a sealant such as an RTV silicone, applied, for example, at the tongue and groove. Alternatively, the second side 280 of the first end piece 274 and the first side 282 of the second piece 276 may comprise flat surfaces and/or grooved surfaces, and they may be sealingly bonded or welded to each other. The bonding or welding prevents relative radial and/or theta (rotational) movement between the first and second end pieces 274, 276.

Similar to the second end cap 108 shown in Figure 2, the second end cap assembly 252 may also include a seal to prevent the fluid from bypassing the filter medium 202 around the second end cap assembly. For example, the seal may be an O-ring seal located either at the inner sidewall or the outer sidewall of the second end cap assembly 252. For example, an O-ring seal may be disposed within a circumferential groove on the outer sidewall of the first or second end piece. When the filter element is installed in the filter housing 10, the O-ring seal preferably forms a piston seal with the inner surface of the cylindrical member 11 of the filter housing 10, preventing bypass of the pressurized fluid around the filter medium.

Alternatively, as shown in Figure 6, the groove 296 may be formed by the second side 280 of the first end piece 274 and a ledge 294 around the outer rim of the first side 282 of the second end piece 276. The circumferential groove 296 may be used to accommodate the O-ring seal 242. In addition to providing a seal between the outer sidewall of the second end cap assembly 252 and the inner sidewall of the cylindrical member 11 of the housing 10, the O-ring seal 242 shown in Figure 6 may also provide a seal between the second side 280 of the first end piece 274 and the first side 282 of the second piece 276. The tie rods 212 may axially compress the O-ring seal 242 against the second side 280 of the first end piece 274 and the end surface of the ledge 294, thus providing a seal between the first and second end pieces 274, 276. When the filter element 200 is installed in a filter housing such as the filter housing 10 shown in Figure 1, the inner wall of the cylindrical member 11 preferably compresses radially the O-ring seal 242, and in response, the O-ring seal 242 may expand axially. The axial expansion may press the O-ring seal 242 against both the second side 280 of the first end piece 274 and the end surface of the ledge 294, enhancing the seal between the second side 280 of the first end piece 274 and the first side 282 of the second end piece 276. Similar to the crud trap 110 shown in Figure 2, the crud trap 210 shown in Figure 6 may be constructed in a number of ways. For example, the first side 282 of the second end piece 276 may also include a cylindrical extension 238 around the inner rim of the second end piece 276. The crud trap 210 may be formed by the outer sidewall of the cylindrical extension 238, the first side 282 of the second end piece 276, and the inner sidewall of the first end piece 274 and/or the filter medium 202. This crud trap 210 may be used to collect loose crud contained in a fluid flowing from the inside to the outside of the filter medium. The cylindrical extension 238 may be attached to the second end piece 276 by any suitable means, including bonding or welding. Preferably, the cylindrical extension 238 and the second end piece 276 may be formed as a unitary part for enhanced strength.

A two-piece end cap assembly has many advantages. One of the advantages is that it facilitates the standardization of filter element parts. For example, among filter elements installed in the same or similar filter housings but having filter media of different configurations and/or materials, the second end pieces, which interface with the filter housing, can be made as standard parts of identical materials which are shared by all the filter elements. The first end pieces and the filter medium, on the other hand, may be variously designed to include different configurations and/or materials. Conversely, among filter elements having the same or similar filter media but installed in different filter housings, the first end pieces and the filter medium can be made as standard parts having identical configurations. The second end pieces, on the other hand, may be variously designed to have configurations or materials which best suit the filter housing in which the filter elements are installed. For example, the second end pieces may have different O-ring seals to adapt to different filter housings or different lifting arrangements to adapt to different lifting devices. The two-piece end cap assembly also enhances the reliability of the filter element.

For example, the first end pieces may have configurations and/or materials that bond well with the filter medium to provide a strong, uniform seal. The second end pieces, on the other hand, may have configurations and/or materials that have sufficient mechanical strength to support the tie rods, to withstand loading on the ends of the filter medium due to increase in pressure drop caused by crud trapped in the filter element, and/or interface with the housing.

Referring now to Figure 8, there is shown another exemplary filter element 300 according to the present invention. The filter element 300 may be used in a variety of applications. For example, the filter element 300 may be mounted within a filter housing of a nuclear power generating system. The filter housing can be variously configured to receive the filter element 300. In Figure 8, for example, the filter housing 20 may include a first housing seal ring 23 distally spaced from a second housing seal ring 21 by a distance slightly greater than the length of the filter element 300. The first housing seal ring 23 may include a circular channel 25 and/or a central aperture 24. The central aperture 24 allows for the flow of liquid from or, preferably, to the filter element 300 from a source. The second housing seal ring 21 may include a ledge 27 upon which the filter element 300 may rest, and a removably secured housing cover 26, e.g., a pivotally secured housing cover. The pivotally secured housing cover 26 preferably can rotate about an axis relative to the second housing seal ring 21 so as to allow for the easy removal or insertion of the filter element 300 in an "open" state and to allow for the creation of a sealed interface in a "closed" state.

The filter element 300 may comprise a filter medium 302 and filter hardware cooperatively arranged with the filter medium 302. The filter hardware may include a filter support such as an outer cage 304, another filter support such as a core (not shown), a second end cap 308, a first end cap 306, a plurality of tie rods 312, a plurality of nuts 348, or any combination of the components listed above. In this embodiment, the outer cage 304 is preferably coaxially disposed along the outer periphery of the filter medium 302 and the first and second end caps 306, 308, respectively, are preferably disposed on opposite end surfaces of the filter medium 302. The end caps 306, 308 can be secured to the filter medium 302 by any other suitable means, including melt, spin or sonic welding, polycapping, or thermal, adhesive or solvent bonding. In addition, a plurality of tie rods 312, a plurality of bolts (not shown), or any other securing means can be used to help secure the end caps 306, 308 to the filter medium 302 and the outer cage 304. These additional securing means may help provide the filter element 300 with tensile strength to counteract the tensile forces acting on the filter element 300 during filtration and during filter insertion and removal. For example, a threaded first end 312A on each of the plurality of tie rods 312 may be screwed into a corresponding threaded aperture 346 in the second end cap 308 which secures the plurality of tie rods 312 to the second end cap 308. Similarly, a threaded second end 312B on each of the plurality of tie rods 312 is disposed through an aperture 344 in the first end cap 306 and screwed to a nut 348 in a recess in the first end cap 306.

The first end cap 306 may be a closed end cap but preferably is an open end cap, as shown in Figure 8. An open end cap allows pressurized liquid on both the first and second opposite sides 320, 322 of the first end cap 306 during filtration. The pressurized liquid on both sides 320, 322 of the first end cap 306 helps to balance the forces on the first end cap 306 and minimize the forces between the first end cap 306 and the housing cover 26. The filter element 300 is preferably sealed to the filter housing 20. For example, the first end cap 306 may include a rim 328 having a seal such as a grooved O-ring seal 330 tucked over the rim 328. Preferably the seal 330 is integral with the first end cap 306 and is removed with the spent filter element 300. The combination of the rim 328 and the grooved O-ring seal 330 may collectively sit on the ledge 27 of the second housing seal ring 21 when the filter element 300 is installed in the filter housing 20. In the illustrated embodiment, the entire weight of filter element 300 rests on the ledge 27. When the housing cover 26 is in the closed position, the grooved O-ring seal 330 may form a face seal with the second housing seal ring 21 and the housing cover 26, preventing leakage of the pressurized fluid between the second housing seal ring 21 and the housing cover 26 and preventing bypass of the pressurized fluid around the filter medium 302. Alternatively, other sealing arrangements may be used, including those disclosed with respect to the other embodiments.

The height of the first end cap 306 is preferably less than the thickness associated with second housing seal ring 21 and the filter medium 302 extends into the second housing seal ring 21. This increases the length and, therefore, the surface area of the filter medium 302 in the envelope defined by the filter housing 20. Flow of the pressurized fluid effectively proceeds through the filter medium 302 in the second housing seal ring 21 and along the interface between the outer cage 304 and the second housing seal ring 21. Consequently, the longer filter medium 302 increases the dirt capacity, the flow capacity, and or the life of the filter element 300.

The second end cap 308 is preferably an open end cap, as shown in Figure 8. The second end cap 308 may include a cylindrical extension 310 having an O-ring seal 342 disposed on an inner surface 311. The cylindrical extension 310 resides in the circular channel 25 of the first housing seal ring 23 when the filter element 300 is disposed within the filter housing 20. For example, when the housing cover 26 is in the closed position, the cylindrical extension 310 surrounds the outer surface 29 of an annular boss 30. The O-ring seal 342 forms a piston seal with the outer surface 29 of the boss 30. Alternatively, an O-ring seal may be disposed within a groove around the outer periphery of the second end cap and sealed to the outer wall of the circular channel 25. The O-ring seal prevents the pressurized fluid from leaking through the gap between the second end cap 308 and the first housing seal ring 23. A gap 58 may exist between the bottom of the circular channel 25 and the bottom of the cylindrical extension 310. The gap 58 is used to take up any tolerances in the filter element 300 when mounted in the filter housing 20.

The filter element 300 may include any or all of the patent features discussed with respect to the filter elements 100, 200. For example, the filter medium 302 and the perforated filter support 304 of the filter element 300 may be the same as or similar to their counterparts 102, 104, 202, 204 in the filter elements 100, 200 shown in Figures 2 and 6, in terms of both materials and constructions. The filter medium 302 may include any suitable separation medium which may have any suitable pore size distribution or removal rating. The filter medium 302 may include a self-supporting fibrous mass or a fibrous sheet or a porous membrane which is wound or pleated and formed into a cylindrical configuration. Preferably, the filter medium 302 comprises a pleated composite.

Similar to the filter support 104, 204 shown in Figures 2-6, the filter support (cage 304 and or core) may be a unitary part or it may preferably comprise a plurality of modular segments. Each modular segment may be a hollow, perforated cylindrical segment 114 as shown in Figures 3 and 4, and the filter support 304 may include a plurality of the cylindrical modular segments 114 attached axially. Alternatively, each modular segment may be a flat or curved rectangular segment 117 as shown in Figure 5, and the filter support 304 may include a plurality of the rectangular modular segments 117 attached circumferentially. Further each cylindrical support segment may comprise one or more rectangular modular segments attached circumferentially. The modular filter supports may be attached to one another by any suitable means, such as welding, bonding and interlocking mechanisms. Various exemplary interlocking mechanisms are described in the discussion on the filter supports shown in Figures 3, 4 and 5. The filter support 304 may be attached to the end caps 306, 308 in any suitable way.

For example, the filter medium 302 and the filter support 304 may be attached to the end caps 306, 308 as a single unit or they can be attached to the end caps 306, 308 separately. To enhance the strength of the attachment between the filter support 304 and the end caps 306, 308, the axial ends of the filter support 304 preferably do not have any configuration, such as detents, perforations or tapers, which may weaken the attachment. Accordingly, at each of its two ends, the filter support 304 may have a segment which has a continuous band at the end that is attached to an end cap. The filter element 300 may also have any of the patentable features of the filter elements 100, 400 shown in Figures 2 and 6. For example, the filter element 400 shown Figure 9, which is similar to the filter element 300, may include a filter medium 402 having first and second ends and first and second end cap assemblies 450, 452 between which the filter medium 402 is disposed. The end cap assemblies 450, 452 combine aspects the end cap assemblies 250, 252 shown in Figure 6 and the end caps 306, 308 shown in Figure 8, and much of the discussion on the end cap assemblies 250, 252 and the end caps 306, 308 is applicable to the end cap assemblies 450, 452. The filter element 400 may also include a first perforated filter support 404 cooperatively arranged with the filter medium 402, a crud trap 410 and one or more tie rods 412 (or any other suitable means, such as welding) extending between the end cap assemblies 450, 452 to secure the filter element 400.

The filter element 400 may include any or all of the patent features discussed with respect to the filter elements 100, 200, 300. For example, the filter medium 402, the perforated filter support 404, and the tie rods 412 of the filter element 400 may be the same as or similar to their counterparts 102, 104, 112, 202, 204, 212 302, 304, 312 in the filter elements 100, 200, 300 shown in Figures 2, 4 and 6, in terms of both materials and constructions.

Like the end cap assemblies 250, 252 shown in Figure 6, at least one of the end cap assemblies 450, 452 may include at least first and second end pieces. In Figure 9, for example, the first end cap assembly 450 includes at least first and second end pieces 454, 456, each having first and second opposite sides 458, 460, 462, 464. The first end piece 454 of the first end cap assembly 450 may be generally annular and may have an opening 466 at its center, although it may have any suitable configuration. The first side 458 of the first end piece 454 is preferably sealingly attached to one end of the filter medium 402 by any suitable means which provides a strong, uniform seal, including melt, spin or sonic welding, polycapping, or thermal, adhesive or solvent bonding. The first end piece 454 may be connected to the second end piece 456 with the second side 460 of the first end piece 454 opposing the first side 462 of the second end piece 456. The first and second end pieces 454, 456 may be connected to each other in any suitable ways. In Figure 9, for example, an adhesive and/or sealant 471 , such as RTV silicon, may be placed between the first and second end pieces 454, 456. Preferably the adhesive and/or sealant 471 forms a continuous circle encompassing the opening 466 of the first end piece 454. The adhesive and/or sealant 471 may then be squeezed by the tie rods 412 between the end pieces 454, 456, bonding the end pieces 454, 456 together and/or sealing the gap between the end pieces 454, 456. Alternatively, any of the methods discussed above, which may be used to connect the end pieces 254, 256, may also be used to connect the end pieces 454, 456.

The second end piece 456 may be variously configured. In Figure 9, for example, the second end piece 456 has the configuration of a basin having first and second sides 464, 462. In other words, the second end piece 456 has the configuration of an annular plate with a cylindrical extension at the rim of the annular plate. The second side 464 of the second end piece 456 may include an annular extension 428, preferably radially outward, defining an outer rim. A slit O-ring seal 430 may be tucked over the annular extension 428. The second end piece 456 may also have an opening 470, which is preferably smaller than the opening 466 of the first end piece 454 so that the tie rods 412 may be attached to the second end piece 456 though the opening 466 on the first end piece 454. The filter element 400 may include a lifting arrangement such as an inverted V-shaped handle 426, as shown in Figure 9, which facilitates the insertion or removal of the filter element 400 into or out of filter housing. Preferably the lifting arrangement is on the second end piece 456. The lifting arrangement may be a unitary part of the second end piece 456 or a separate, attachable piece. In Figure 9, the handle 426 are attached at its two ends to the inner surface of the second end piece 456. Preferably the apex of the inverted V-shaped handle 426 is aligned vertically with the center of the second end piece 456. The second end cap assembly preferably also includes at least first and second end pieces. For example, in the embodiment illustrated in Figure 9, the second end cap assembly 452 preferably includes at least first and second end pieces 474, 476, each having first and second opposite sides 478, 480, 482, 484. Similar to the first end piece 474 of the first end cap assembly 450, the first end piece 474 of the second end cap assembly 452 may be generally annular with a circular opening 486 at its center. The second end piece 476 of the second end cap assembly 452 also has an opening 490 at its center. This opening 490 together with the opening 486 in the first end piece 474 may serve as an outlet or, preferably, an inlet to the filter element. The opening 490 is preferably smaller than the opening 486 on the first end piece 474 so that the tie rods 412 may be attached to the second end piece 476 though the opening 486 on the first end piece 474.

The first side 478 of the first end piece 474 may be sealingly attached to the other end of the filter medium 402. The attachment may be accomplished by any suitable means which provides a strong, uniform seal, including melt, spin or sonic welding, polycapping, or thermal, adhesive or solvent bonding. The first end piece 474 may be connected to the second end piece 476 with the second side 480 of the first end piece 474 opposing the first side 482 of the second piece 476. The connection between the first and second end pieces 474, 476 may be similar to the connection between the first and second end pieces 454, 456 of the first end cap assembly.

The second end piece 476 may also have the configuration of a basin having an annular plate with a cylindrical extension 477 at the rim of the annular plate. An O-ring seal 442 may be disposed in a groove 441 on the inner surface 411 of the cylindrical extension 477. When the filter element 400 is disposed within the filter housing 20 shown in Figure 8, the cylindrical extension 410 resides in the circular channel 25 of the first housing seal ring 23, and the O-ring seal 442 forms a piston seal with the outer surface 29 of the boss 30. The O-ring seal 442 prevents the pressurized fluid from leaking through the gap between the second end piece 476 and the first housing seal ring 23. Alternatively, an O-ring may be disposed within a groove around the outer periphery of the second end piece. Similar to the crud trap 110, 210 shown in Figures 2 and 6, the crud trap 410 may be constructed in a number of ways. For example, the first side 482 of the second end piece 476 may include a cylindrical extension 438 around the inner rim of the second end piece 476. The crud trap 410 may be formed by the outer sidewall of the cylindrical extension 438, the first side 482 of the second end piece 476, and the inner sidewall of the first end piece 474 and/or the filter medium 402. The cylindrical extension 438 may be attached to the second end piece 476 by any suitable means, including bonding or welding. Preferably, the cylindrical extension 438 and the second end piece 476 may be formed as a unitary part for enhanced strength.

While the invention has been described in terms of several embodiments, it is not limited to those embodiments. Rather, the invention encompasses all modifications, equivalents, and alternatives that are within the spirit and scope of the following claims.

Claims

1. A filter element comprising: a filter medium; and at least a first perforated filter support cooperatively arranged with the filter medium, the first perforated filter support including a plurality of modular segments, the plurality of modular segments being attached to one another.

2. The filter element according to claim 1 wherein the first perforated filter support is a cage disposed adjacent to an outer periphery of the filter medium.

3. The filter element according to claim 1 wherein the first perforated filter support is a core disposed adjacent to an inner periphery of the filter medium.

4. The filter element according to claim 1, 2 or 3 wherein each modular segment is a hollow, perforated cylindrical segment.

5. The filter element according to claim 1, 2 or 3 wherein each modular segment is a generally rectangular perforated strip.

6. The filter element according to claim 4 wherein each hollow, perforated cylindrical segment comprises a rectangular perforated strip having opposite edges, the opposite edges being attached to each other.

7. The filter element according to claim 4 wherein each hollow, perforated cylindrical segment comprises one or more rectangular perforated strips attached to one another.

8. The filter element according to any of the preceding claims wherein the filter medium has first and second ends, and wherein first and second end cap assemblies disposed at the first and second ends of the filter medium, each of the first and second end cap assemblies including at least first and second end pieces.

9. A filter element comprising: a filter medium having first and second ends; first and second end cap assemblies disposed at the first and second ends of the filter medium, the first end cap assembly including at least first and second end pieces, wherein each of the first and second end pieces has first and second opposite sides with the second side of the first end piece opposing the first side of the second piece.

10. The filter element according to claim 9 wherein the second end cap assembly comprises at least first and second end pieces, each of the first and second end pieces of the second end cap assembly has first and second opposite sides with the second side of the first end piece of the second end cap assembly opposing the first side of the second piece of the second end cap assembly.

11. The filter element according to any of the preceding claims comprising a handle.

12. The filter element according to any of the preceding claims comprising a crud trap.

13. A method of assembling a filter element comprising: assembling a perforated filter support from a plurality of modular segments; and disposing the perforated filter support adjacent to a filter medium.

14. The method of assembling a filter element according to claim 13 comprising connecting an end cap assembly at each of two ends of the filter medium, wherein each of the end cap assembly includes at least first and second end pieces.

15. A method of assembling a filter element comprising: assembling a filter end cap assembly by connecting a first end piece with a second end piece with the first side of the second end piece facing the second side of the first end piece; and bonding the first side of the first end piece to an end of a filter medium.

16. A filter element comprising: a filter medium; and filter hardware cooperatively ananged with the filter element wherein the filter medium comprising a compound selected from the group comprising aromatic polyamide and polypropylene.

17. A filter element comprising: a filter medium; and filter hardware cooperatively arranged with the filter medium, wherein the filter hardware comprises a compound selected from the group comprising polyetherimide and polyetheretherketone.

18. The filter element according to claim 17 wherein the filter medium comprising a compound selected from the group comprising aromatic polyamide and polypropylene.

19. The filter element of claim 16, 17, or 18 wherein the filter hardware is selected from the group comprising a bolt, a rod, a nut, an open end cap, a closed end cap, an outer cage, and a core.

20. A filter element adapted to be installed in a filter housing which includes an first housing seal ring, the first housing seal ring having a known thickness and including a filter aperture, the filter aperture including a ledge, the filter element comprising: a filter medium having a first end surface; and a first end cap attached to the first end surface of the filter medium, the first end cap having a height less than the thickness of the first housing seal ring, the first end cap including a rim having a seal tucked over the rim whereby, when the filter element is installed into the filter aperture and the seal rests on the ledge, the filter element extends into the filter aperture.