1. Field of the Invention
The invention relates to filter vessels used to filter gas and liquid streams and to filter elements for such vessels, and, more specifically, to an improved seal structure and method for mounting the filter elements within the interior of the associated filter vessel.
2. Description of Related Art
Gas filter elements for filtering dry gas streams as well as for separating solids and liquids from contaminated gas streams are well known, as are gas filter elements for coalescing entrained liquids from a gas stream. These general types of gas filter elements may be installed in single stage or multi-stage vessels, which are in turn installed in a gas pipeline, to perform the required filtering functions. For example, Perry Equipment Corporation of Mineral Wells, Tex., offers the “Series 85, 88 and 90” Gas Filter and Filter/Separator Units.” The “Series 85 Filter/Separator” is a two stage unit. The first stage employs PEACHY filter-coalescing filter elements, also commercially available from Perry Equipment Company. These elements remove the solids contamination and coalesce any entrained liquid droplets. The coalesced liquid is then removed in the second stage high efficiency vane mist eliminator and collected in the liquid sump to be drained. The “Series 90 Filter/Separator” is designed for filtering dry gas or air streams. These units are useful in removing desiccant fines, pipe scale and other solid contaminants on the order of one micron and larger. They employ single stage filtration and are capable of utilizing a number of different filter element styles.
In the area of liquid filtration, the PECO® “Series 57” and “PEACH® TRITON LIQUIPUR® Series 58” liquid filtration units meet industrial ASME code for filtering liquid flows ranging from about 1 GPM to 3900 GPM or upwards. They are designed to use a multitude of string/pleated and PEACH® type filter elements for almost any liquid filtering application.
In the patent literature, U.S. Pat. No. 5,919,284, issued Jul. 6, 1999, and U.S. Pat. No. 6,168,647, issued Jan. 2, 2001, both to Perry, Jr., and assigned to the assignee of the present invention, disclose multi-stage vessels using individual separator/coalescer filter elements to separate solids, filter liquids, and coalesce liquids. The foregoing multi-stage vessels, as well as a multitude of other similar filtration vessels used in industry utilize solid or hollow core tubular elements, typically formed at least partially a porous filtration media. For example, the PEACHY porous filtration elements useful in the above type of filtration vessels are of the same general type as those that are described in U.S. Pat. No. 5,827,430, issued Oct. 27, 1998 to Perry, Jr., et al., and assigned to the assignee of the present invention.
Despite advances made in filter/separator vessel technology, a need continues to exist for an improved filter element seal structure and mounting method for mounting filter elements in vessels of the above discussed type.
A need exists for an improved seal structure for filter elements of the above type which is simple in design and relatively economical to manufacture and yet which presents a reliable and effective sealing action in a variety of different sealing applications.
An improved seal structure is shown for a tubular filter element used to filter a fluid stream in an industrial process where the fluid stream passes through a filter vessel having rigid risers for mounting the filter elements. Each of the filter elements comprises a tubular body with generally cylindrical sidewalls formed of a porous material, an interior, a first end opening and an oppositely arranged second end opening. The improved seal structure of the invention is comprised of a resilient body having conically shaped sidewalls which are tapered with respect to a central axis of the resilient body and which extend between a first lip region and a second lip region of the body. A selected one of the first and second lip regions of the resilient body is adapted to seal on a selected end opening of the filter element. The conically shaped sidewalls of the filter element form a dynamic seal with the riser element of the filter vessel on which the filter element is mounted and with the filter element body when subjected to a pressure differential between an upstream portion of the process and a downstream portion of the process being filtered.
A selected one of the first and second lip regions of the body of the seal structure terminates in a flared collar region also formed of a resilient material and with opposing exposed sides. One of the opposing exposed sides of the collar region seals against an end opening of the filter element and the other opposing side seals against the vessel riser. In one version of the seal structure, the collar region is a planar member of generally uniform thickness. The vessel riser may terminate in a flat planar surface or may have a circumferential thimble region which forms a relatively narrow edge at an outer extent thereof, the selected opposing exposed side of the flared collar region of the seal structure forming a compression seal with the edge of the circumferential thimble region of the riser as the edge bites into the collar region of the seal structure in use. The seal formed between the thimble region of the riser and the flared collar region of the seal structure is in the nature of a flat gasket compressive seal, while the seal formed between the conically shaped sidewalls of the seal structure and the riser interior is an annular seal along the length of the conically shaped sidewalls which is energized by the differential pressure created between existing upstream and downstream process conditions.
In another version of the seal structure, the collar region forms a circumferential recess on one side thereof to engage one end of the filter element sidewalls. The conically shaped tapered sidewalls of the seal structure form a relatively larger outer diameter flared bottom for the seal structure which extends upwardly toward a relatively narrower top region of the seal structure. The seal structure is received within the interior of the generally tubular body of the filter element with the flared bottom forming a seal with a selected end of the filter element. The vessel riser extends upwardly within the interior of the filter element interior and within an interior region of the seal structure where it contacts and seals against the seal structure in use. The seal structure extends for a predetermined length between the opposing outer lips thereof, whereby the length of the seal structure occupies a given distance within the interior of the filter element and as a result liquid flow through the element from the inside to the outside thereof is directed higher up the interior of the filter element than would occur without the sealing element being present within the interior of the filter element.
A filter element and improved seal structure are also shown for an apparatus that is used for filtering a gas or liquid stream such as a natural gas stream or a natural gas processing liquid stream. The apparatus includes a closed vessel having a length and an initially open interior. A partition is disposed within the vessel interior. The partition has a planar inner and planar outer side, respectively, dividing the vessel interior into a first chamber and a second chamber. At least one opening is provided in the partition over which is provided a rigid riser for mounting a filter element. An inlet port is provided in fluid communication with the first chamber. An outlet port also provides fluid communication from the second chamber. At least one tubular filter element is disposed within the vessel and mounted upon the rigid riser. The filter element comprises a tubular body with generally cylindrical sidewalls formed of a porous material, an interior, a first end opening and an oppositely arranged second end opening as previously described. The above described seal structure with its resilient body and conically shaped sidewalls are used to form a secure seal with the vessel riser. The conically shaped sidewalls of the filter element form a dynamic seal with the riser element of the filter vessel on which the filter element is mounted and with the filter element body when subjected to a pressure differential between an upstream portion of the process and a downstream portion of the process being filtered.
The above as well as additional objects, features, and advantages of the invention will become apparent in the following detailed description.
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Referring again to
The partition 29 which divides the vessel interior into the first and second filtration chambers has a planar inner and planar outer opposing sides 33,35, respectfully. An opening is provided in the partition 29 for each filter element to be mounted thereon. A vertically extending riser 31 is mounted over each partition opening, as by welding, for receiving an end of a filter element. An inlet port 37 is in fluid communication with the first chamber and an outlet port 39 is in communication with the second chamber. The tubular filter elements 27 are disposed within the vessel to sealingly extend within the second chamber and to communicate through the associated riser and its associated opening in the partition 29 into the first chamber of the vessel. Gas flow is through the inlet port 37, through the first chamber, through the riser interiors, into a hollow interior of the filter elements 27 and out the sidewalls thereof, and through the second chamber to the outlet 39. The direction of the gas flow is indicated by the arrows in
Each of the filter elements 27 (
The bodies, or tubular filter walls of the filter elements of the invention can be formed of any material conventionally used in the art. The construction of the filter elements will vary depending upon the particular end application of the filtration vessel. By way of example, the filter elements can be constructed in the manner and of the materials disclosed in U.S. Pat. No. 5,827,430, issued Oct. 27, 1998 to Perry, Jr., et al. Such filter elements are sold commercially under the PEACH® trademark by Perry Equipment Corporation of Mineral Wells, Tex. In a typical application, the filter elements consist of four multi-overlapped layers of non-woven fabric strips of varying composition. The first layer is composed of equal amounts by volume of fibers purchased commercially from Hoechst Celanese under the fiber designations “252,” “271,” and “224,” and has a basis weight of 0.576 ounces per square foot, is ten inches wide, and is overlapped upon itself five times. The denier of fiber “252” is 3 and its length is 1.500 inches. The denier of fiber “271” is 15 and its length is 3.000 inches. The denier of fiber “224” is 6 and its length is 2.000 inches.
The second layer is composed of equal amounts by volume of “252,” “271,” and “224,” has a basis weight of 0.576 ounces per square foot, is eight inches wide, and is overlapped upon itself four times. The third layer is composed of equal amounts by volume of “252,” “271,” and “224,” has a basis weight of 0.576 ounces per square foot, is eight inches wide, and is overlapped upon itself four times. The fourth layer is composed of equal amounts by volume of “252” and a fiber sold under the name “Tairilin,” has a basis weight of 0.576 ounces per square foot, is six inches wide, and is overlapped upon itself three times. Fiber “252” being of the core and shell type serves as the binder fiber in each of the aforementioned blends.
The above example of particular types of material, fabric denier, number of wrapping layers, etc., is intended to be illustrative only of one type of filter material useful in the practice of the present invention. The seal structure of the elements of the invention could be used with a variety of other conventional filter materials, as well.
A seal structure (53 in
At least a selected one of the first and second lip regions 59, 61 of the resilient body 53 is adapted to seal on a selected end opening 45, 47 of the filter element 27. In the embodiment of the seal structure 53 shown in
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An invention has been provided with several advantages. The seal structure of the invention is simple in design and economical to manufacture. The seal structure of the invention has multiple areas where the seal will contact the filter element support structure to maintain positive sealing surfaces. The result is more effective sealing area than was available from the prior art arrangements featuring gasket and o-ring type seals. The seal structure of the invention can be used in a wide variety of process applications involving both liquid and gas filtration. The improved seal structure provides an annular seal which utilizes the differential pressure between the upstream and downstream sides of the filter element to aid in effecting an improved seal.
While the invention is shown in only one of its forms, it is not just limited but is susceptible to various changes and modifications without departing from the spirit thereof.