The present invention relates to lined piping systems, and more particularly to a profiled gasket for flanged joints in a lined piping system.
Internally lined piping systems are used in numerous commercial applications by the pharmaceutical, chemical, petroleum, food, and other industries for transporting and processing products and chemicals in dry, liquid, or gaseous forms and combinations thereof. Lined piping generally includes two components: (1) a tubular metallic outer jacket or pipe which provides strength for pressure retention and support, and (2) an inner liner applied or affixed thereto. The liners are typically made of a chemically and/or abrasion resistant non-metallic material. The choice of liner materials depends on the intended use, such as to prevent contamination of the product by the outer pipe or conversely to prevent the outer pipe from corrosion, abrasion, or chemical attack caused by the transported media. Some common liner materials used include without limitation Polytetrafluoroethylene (PTFE), Polypropylene (PP), Perfluoroalkoxy (PFA), Polyvinylidene Difluoride (PVDF), Polyvinylidene Chloride (PVDC), Ethylenetetrafluoroethylene (ETFE), elastomerics, glass, ceramic glass, and others. Accordingly, various plastic-lined and glass-lined piping is commercially available and used in many applications.
Flanged connections may be used for joining multiple sections of lined pipe to create various piping system configurations and/or to connect the lined piping to various types of in-line components such as valves, pumps, process tanks, mixers, etc. One common arrangement of a flanged piping assembly for a lined piping system is shown in U.S. Pat. Nos. 4,313,625 and 4,643,457, both of which are incorporated herein by reference in their entireties. The inner pipe liner is gradually flared at the end with respect to the longitudinal axis of the piping and protrudes radially outward beyond the terminal end of the pipe to at least partially cover and extend across a portion of the end face of the radially-extending flange. In some embodiments, such as in the case of plastic-lined pipe, the flared liner may be made by heating an exposed end of the liner followed by flaring or molding the liner over against the end face of the flange. A pressure seal is formed by compression at the piping joint by the mating inner liners of adjoining sections of piping when the flanges are coupled together by bolting, clamping, or other similar compression assembly means. Accordingly, this design eliminates the need for any additional gaskets or sealing members since the abutting flared or formed liner portions creates the seal and prevents the flowing material from contacting the metal outer pipe at the joints.
As more clearly shown herein in
An improved lined piping system flange joint with less, and preferably zero, dead-space is desirable.
The present invention provides a specially profiled gasket that reduces the foregoing problems in lined piping systems utilizing flanged joints. In one embodiment, the gasket is configured and adapted to minimize or eliminate the dead space that would otherwise form at the flange joints between the liners. This embodiment prevents the accumulation of debris that might otherwise lead to contamination of the flowing product. Advantageously, this embodiment is intended to greatly reduce or preferably eliminate the need for periodic disassembly of the piping systems to remove the accumulated debris. Furthermore, this embodiment is intended to facilitate the use of a more cost-effective flanged lined piping system rather than conventional sanitary-grade systems having zero dead-space clamped joints.
According to one embodiment of the present invention, a lined piping assembly defining an interior flow path and a longitudinal axis includes: a first piping section terminated with a first flange and including an inner liner having a first flared portion extending radially outward along an end face of the first flange, the first flared portion defining a first convex liner end surface; a second piping section terminated with a second flange and including an inner liner having a second flared portion extending radially outward along an end face of the second flange, the second flared portion defining a second convex liner end surface; the first and second flared portions of the liners forming a gap therebetween having a narrow portion distal to the interior flow path of the piping assembly and a wider portion proximal to the interior flow path of the piping assembly; and a profiled gasket disposed between the first and second flared portions and having a configuration that fills the gap. By filling the gap, the profiled gasket serves to prevent accumulation of material at the juncture of the first and second flanges.
According to another embodiment of the present invention, a lined piping assembly defining an interior flow path and a longitudinal axis includes: a first piping section terminated with a first flange and including an inner liner having an axial portion and a radial portion extending radially outward along an end face of the first flange, the liner having a first rounded convex end surface formed at a transition between the axial and radial portions of the liner; a second piping section terminated with a second flange and including an inner liner having an axial portion and a radial portion extending radially outward along an end face of the second flange, the liner of the second piping section having a second rounded convex end surface formed at a transition between the axial and radial portions of the liner, the first and second rounded convex end surfaces defining an annular V-shaped gap therebetween opening into the interior flow path of the piping assembly when the first and second flanges are positioned proximate to each other; and a profiled gasket disposed between the first and second flanges, the gasket having a pair of concave side surfaces facing in opposing directions, each side surface being configured to engage one of the first and second rounded convex end surfaces for filling the annular V-shaped gap when the first and second flanges are drawn together.
According to another embodiment of the present invention, a lined piping assembly defining an interior flow path and a longitudinal axis includes: a first piping section terminated with a first flange and including an inner liner having an axial portion and a radial portion extending radially outward along an end face of the first flange, the liner having a first rounded convex end surface formed at a transition between the axial and radial portions of the liner; a second piping section terminated with a second flange and including an inner liner having an axial portion and a radial portion extending radially outward along an end face of the second flange, the liner of the second piping section having a second rounded convex end surface formed at a transition between the axial and radial portions of the liner; and a gasket including a generally V-shaped portion when viewed in cross-sectional profile for positioning along the interior flow path, the gasket having a width that gradually narrows in a radial direction away from the flow path, the gasket being engaged between the first and second convex end surfaces of the liners for forming a pressure seal when the first and second flanges are drawn together.
According to yet another embodiment of the present invention, a lined piping assembly defining an interior flow path and a longitudinal axis includes: a first piping section including a first flange and an inner liner having a first flared portion extending radially outward from an end of the first piping section, the first flared portion defining a first convex liner end surface; a second piping section including a second flange and an inner liner having a second flared portion extending radially outward from an end of the second piping section, the second flared portion defining a second convex liner end surface; the first and second flared portions of the liners being abutted and forming a V-shaped gap therebetween with the wider portion of the V-shaped gap located proximal to the interior flow path of the piping assembly; and a profiled gasket disposed between the first and second flared portions of the liners and having a configuration that fills the V-shaped gap when the first and second flared portions are drawn together to prevent accumulation of material in the gap. In one embodiment, the first and second flared portions of the liners each extend radially outward along the face of the first and second flanges, respectively. In another embodiment, the first and second flared portions of the liners each extend radially outward along a radially flared portion of the end of the first and second piping sections, respectively, wherein the first and second piping sections have lapped pipe ends. In one embodiment, the first and second flanges may be loose-fitting lap joint rotating flanges.
In another embodiment, the present invention provides a profiled annular gasket adapted for flanged piping joints used in a lined piping system defining an interior flow path, which gasket includes: an annular inner portion for positioning along an interior flow path of a piping system, the annular inner portion having an axial width that gradually narrows in a radial direction away from the flow path; an annular outer portion adjacent to the inner portion; a pair of sides extending between the annular inner portion and the annular outer portion; and a recessed annular side surface disposed in each side of the gasket, each side surface being adapted and configured to engage a convex end surface of an inner liner of a pipe section. Preferably, the gasket is engageable between an opposing pair of the end surfaces defined by inner liners of two abutting pipe sections at a piping joint. The gasket forms a pressure seal when the piping sections are drawn together. In one embodiment, the piping joint is a flanged joint.
The features of several embodiments of the present invention will be described with reference to the following drawings where like elements are labeled similarly, and in which:
All drawings are schematic and not drawn to scale.
In the description of embodiments of the present invention disclosed herein, any reference to direction or orientation is merely intended for convenience of description and is not intended in any way to limit the scope of the present invention. Moreover, although the features and benefits of the invention are illustrated by reference to particular embodiments, the invention expressly should not be limited to such embodiments illustrating some possible but non-limiting combination of features that may be provided alone or in other combinations of features.
Referring to
Pipe sections 10, 20 each define a longitudinal axis “LA” extending along the flow path P which is defined and referred to herein as the axial direction. A radial direction is defined as being transverse or perpendicular to the longitudinal axis LA and the term as used herein is given its conventional meaning in the art. Each pipe section 10, 20 has an inside diameter Di measured between diametrically opposed inner surfaces 13, 23 of liners 18, 28, respectively. Each pipe section 10, 20 further has an outside diameter Do measured between diameter opposed exterior surfaces of outer pipes 11, 21.
With continuing reference to
With continuing reference to
It will therefore be appreciated that the flanges may be of any type suitable for use with lined piping systems wherein the piping liners are abutted to form a joint, including but not limited to loose lap joint/rotating flanges, slip-on welded flanges, socket weld flanges, weld-neck flanges, threaded flanges, etc. Accordingly, the invention is not limited to, or for use in, any particular type of flange.
In one embodiment, with reference to
With continuing reference to
Referring to
With continuing reference to the embodiment shown in
With continuing reference to
Inner portion 41 of gasket 40 further defines an inner axial gasket face 43 which is in direct communication with the flow path P and exposed to the material or media being transported in piping sections 10, 20. Accordingly, gasket face 43 forms part of the flow path P in the interior 30 of piping sections 10, 20 when installed between flanges 15 and 25. In one embodiment, inner gasket face 43 has a substantially flat surface which preferably aligns with and is parallel to axial liner portions 18, 28 as shown. In this embodiment, the inside diameter of gasket 40 measured between diametrically opposed sections of gasket at face 43 is approximately equal to the inside diameter Di of piping sections 10 and 20 measured between diametrically opposed inner surfaces 13, 23 of liners 18, 28 to form a relatively smooth flow path P without gaps between the flanges. In other embodiments as shown in
Gasket 40 further includes an outer portion 42 that is disposed opposite inner portion 41 as shown in
Referring to
With continuing reference to
In a further embodiment, with reference to
Profiled gasket 40 may be made of any suitable metallic or non-metallic material depending on the requirements of the intended application. In a preferred embodiment, gasket 40 is made of a pharmaceutical-grade or food-grade compatible material suitable for use where a chemically resistant lined process piping system is needed. In some embodiments, gasket 40 may be made of a relatively resilient and deformable material such as PTFE, enhanced PTFE, reinforced PTFE or other suitable materials compatible with pharmaceutical-grade or food-grade sanitary process piping systems. In other embodiments, gasket 40 may be made of a relatively hard or minimally deformable non-metallic material such as carbon fiber, para-aramid synthetic fiber such as Kevlar™ available from E. I. du Pont de Nemours and Company of Wilmington, Del., polyamide-imide such as Torlon® available from Solvay Advanced Polymers of Alpharetta, Ga., composites, or similar. In yet other embodiments, gasket 40 may be made of a hard metallic material such as wrought corrosion-resistant nickel-molybdenum-chromium alloy such as Nikelvac HC276™, pharmaceutical grade stainless steels, and other similar metals. In other embodiments, gasket 40 may be made of any non-metallic or metallic material for non-sanitary grade process piping. Accordingly, it will be appreciated that the invention is not limited to any particular material for gasket 40. It is well within the ambit of those skilled in the art to select a material appropriate for the intended application.
Gasket 40 may be made by any suitable commercial manufacturing process typically used to make gaskets; the particular process selected for manufacture being dependent upon the type of material selected for the gasket. Gasket 40 may therefore be made by techniques including, without limitation, molding, casting, forging, machining, and combinations thereof or other suitable methods.
Although embodiments of the invention have been most conveniently described with reference to connection of two piping sections, it will be appreciated that the invention may be used in connecting any type of inline components of a piping or conveying system. In addition, embodiments according to principles of the present invention may be used in any type of fluid transport system for conveying solids, liquids, gases or combinations thereof where it is desirable to eliminate dead zones at piping joints. Some exemplary applications include without limitation conveying abrasive slurries where annular gaps at the piping joints can increase fluid turbulence resulting in abrasion and erosion of the piping liner at the flanged joints; pneumatic/vacuum transport of dry solids suspended in air or other gases; liquid transport with or without dissolved solids or solids in suspension, etc. In addition, it will be appreciated that the invention may be used with any type of lined piping system including plastic-lined piping, glass-lined piping, elastomeric or rubber lined piping, etc. Accordingly the invention is not limited in use to any particular type of inner liner material.
While the foregoing description and drawings represent the preferred embodiments of the present invention, it will be understood that various additions, modifications and substitutions may be made therein without departing from the spirit and scope of the present invention as defined in the accompanying claims. In particular, it will be clear to those skilled in the art that the present invention may be embodied in other specific forms, structures, arrangements, proportions, sizes, and with other elements, materials, and components, without departing from the spirit or essential characteristics thereof. One skilled in the art will appreciate that the invention may be used with many modifications of structure, arrangement, proportions, sizes, materials, and components and otherwise, used in the practice of the invention, which are particularly adapted to specific environments and operative requirements without departing from the principles of the present invention. The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being defined by the appended claims, and not limited to the foregoing description or embodiments.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/IB2009/005597 | 4/28/2009 | WO | 00 | 10/29/2010 |
Number | Date | Country | |
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61049554 | May 2008 | US |