Patent Publication Number: US-2011049878-A1

Title: Profiled Gasket For Lined Piping

Description:
The present invention relates to lined piping systems, and more particularly to a profiled gasket for flanged joints in a lined piping system. 
     BACKGROUND OF THE INVENTION 
     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  FIG. 1 , however, each of mating flanges in the foregoing known joint design has a smooth, gradual inner liner radius R formed where the liner is flared outward and transitions between the inside axial portion of the pipe and end face of the flange. The radius defines convex, rounded end surface R that forms a smooth transition in contrast to sharp 90-degree liner end edges as found in other known designs such as shown in U.S. Pat. No. 5,876,070, which is incorporated herein by reference in its entirety. Accordingly, when two lined flanges with smooth convex edges are coupled together, this creates a V-shaped annular groove or gap G between flanges at the adjoining sections of inner liners. The gap G results in a “dead-zone” where flowing material or product may collect in the piping system such as, for example, in pneumatic or vacuum material transport, liquid, liquid slurry, or other type of fluid piping systems. In pharmaceutical final product and/or food-grade lined piping system applications that must meet rigid sanitary standards, such product accumulation is undesirable and may lead to eventual contamination of the product over time. This requires periodic disassembly of the flanged piping joints to remove the accumulated debris or product, which is time consuming, increases maintenance expenses, and adds to final product costs. Although in some applications, food grade and pharmaceutical grade “sanitary-type” piping systems employing special clamped fittings having zero dead-space may be used to eliminate dead-zones (such as Tri-Clover® fittings available from Alfa Laval of Richmond, Va.), these systems are more expensive than a lined flange joint system. 
     An improved lined piping system flange joint with less, and preferably zero, dead-space is desirable. 
     SUMMARY OF INVENTION 
     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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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: 
         FIG. 1  is a partial cross-sectional side view of a prior art flanged joint for a lined piping system; 
         FIG. 2  is a magnified view of a portion of  FIG. 1 ; 
         FIG. 3  is a partial cross-sectional side view of a first embodiment of a gasket and flanged joint for a lined piping system according to the present invention; 
         FIG. 4  is a magnified view of a portion of  FIG. 3 ; 
         FIG. 5  is a partial cross-sectional side view of a second embodiment of a gasket and flanged joint for a lined piping system according to the present invention; 
         FIG. 6  is a magnified view of a portion of  FIG. 5 ; 
         FIG. 7  is a partial cross-sectional side view of the gasket of  FIGS. 3 and 4  according to the present invention; 
         FIG. 8  is a partial cross-sectional perspective view of the gasket of  FIGS. 3 and 4  according to the present invention; 
         FIG. 9  is a detailed partial cross-sectional side view of a third embodiment of a gasket and flanged joint for a lined piping system according to the present invention; and 
         FIG. 10  is a partial cross-sectional side view of an alternative embodiment of a flanged joint for a lined piping system in the form of a pipe lap joint and gasket of  FIGS. 3 and 4  according to the present invention. 
     
    
    
     All drawings are schematic and not drawn to scale. 
     DETAILED DESCRIPTION OF THE INVENTION 
     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. 
       FIGS. 3 and 4  show a first embodiment of a profiled gasket that is configured to fill the gap or “dead zone” (see, e.g.  FIG. 2 ) that may otherwise be created at flanged joints in a lined piping system. Lined pipe useable with this profiled gasket may be, for example, Resistoflex™ brand piping available from Crane Resistoflex Corporation of Marion, N.C. 
     Referring to  FIGS. 3 and 4 , one embodiment of a lined piping assembly is shown in the form of a flanged joint  35  that couples together two adjoining piping sections  10 ,  20 , each section having an inner liner ( 12 ,  22 ). The flanged joint is coupled by conventional flange bolting including a plurality of bolts  60  and nuts  62 . Piping sections  10  and  20  collectively define an interior  30  and an exterior  31  of the coupled piping assembly. Pipe section  10  includes an outer jacket or pipe  11  and an inner liner  12  having an inner surface  13  defining a flow path P therethrough. Pipe section  20  similarly includes an outer jacket or pipe  21  and an inner liner  22  having an inner surface  23  defining a flow path P therethrough. Although flow path P is shown in a direction from left to right, it will be appreciated that flow path P may be in an opposite direction and in any orientation including horizontal, vertical, or at an angle therebetween. In some embodiments, either one or both of pipe sections  10 ,  20  may be any type of pipe section including a nipple or similar connection disposed on various in-line piping system components and equipment such as, without limitation, fittings (e.g. elbows, tees, etc.), valves, pumps, strainers, process tanks, heaters, etc. adapted to connect to a piping system. Accordingly, the invention is not limited in use to piping-to-piping joints alone. 
     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  FIGS. 3 and 4 , outer pipes  11 ,  21  may be made of any suitable material commonly used in commercially-available lined piping systems. In some embodiments, outer pipes  11 ,  21  may be, for example, metal, such as without limitation steel, aluminum, copper, brass, cast iron, or other suitable metals. Inner liners  12 ,  22  may be, for example, made of any suitable materials commonly used in conventional lined piping systems, such as without limitation PTFE, PP, PFA, PVDF, elastomerics, rubbers, and others. In a preferred embodiment, inner liners  12 ,  22  are made of a pharmaceutical-grade or food-grade material of the type used in sanitary piping systems. 
     With continuing reference to  FIGS. 3 and 4 , pipe sections  10 ,  20  each have terminal ends  14 ,  24  that are terminated in one embodiment with radial flanges  15 ,  25  extending in a radial direction transverse to longitudinal axis LA. Flanges  15 ,  25  each define respectively a radial end face  17 ,  27  for mating to an opposing flange. Flanges  15 ,  25  may be formed as an integral part of outer pipes  11 ,  21 , or as separate components attached to outer pipes  11 ,  21  by welding, threading, or other suitable conventional means used in the art, or loose. In one embodiment, flanges  15 ,  25  may be welded to outer pipes  11 ,  21 . 
     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  FIG. 3 , flanges  15 ,  25  each include a plurality of conventional circumferentially-spaced bolting holes  16 ,  26  configured to receive flange bolts  60  used with nuts  62  for coupling the two flanges together and drawing piping sections  10  and  20  together. However, other suitable means such as, without limitation, clamping may be used to couple the flanges together. 
     With continuing reference to  FIGS. 3 and 4 , in one embodiment, inner liner  12  has a flared portion that extends radially outward from the interior  30  of pipe section  10  in a direction transverse to longitudinal axis LA, and more preferably along at least a portion of radial end face  17  of flange  15  as shown to form part of a pressure seal at the flange joint. In one embodiment, accordingly, inner liner  12  is a continuous element that includes a flared radial flange liner portion  19  (see  FIG. 4 ) and a contiguous axial liner portion  18  extending along longitudinal axis LA. Similarly, in one embodiment, inner liner  22  of pipe section  20  also preferably has a flared portion that extends radially outward along at least a portion of radial end face  27  of flange  25  in the same manner to be coupled with opposing end face  17  of flange  15 , as further described herein. Inner liner  22  therefore may also be a continuous element that includes a flared radial liner portion  29  (see  FIG. 4 ) and a contiguous axial liner portion  28  extending along longitudinal axis LA. In one embodiment, inner liners  12 ,  22  are permanently adhered to their respective outer pipes  11 ,  21  and flanges  15 ,  25 . 
     Referring to  FIG. 4 , liners  12  and  22  define a radial, generally convex liner end surface R 1  formed at a transition between radial liner portions  19 ,  29  and axial liner portions  18 ,  28  (shown in  FIG. 3 ), respectively. Convex liner end surface R 1  may be rounded and smooth in cross-sectional profile in some embodiments as shown ( FIGS. 3-6 ). In other embodiments (e,g, as shown in  FIG. 9 ), convex liner end surface R 3  may be chamfered or angled in cross-sectional profile. Since the convex liner end surface shape of the applied liner will be generally dictated by the shape of the underlying pipe end preparation used (as shown, e.g., in  FIGS. 4 and 9 ), numerous variations are possible in the liner end surface shape. Accordingly, the invention is not limited to gaskets fitting any particular liner end surface shape. 
     With continuing reference to the embodiment shown in  FIGS. 3 and 4 , an annular and generally triangular (or V-shaped) groove or gap G is formed between flanges  15  and  25  when pipe sections  10 ,  20  are positioned proximate to each other as shown (see also  FIG. 2 ). Gap G extends circumferentially along the inner surfaces  13  and  23  of inner liners  12 ,  22  of pipe sections  10  and  20 , respectively. The widest portion of gap G lies closest to inner surfaces  13 ,  23  proximal to the flow path P and the narrowest portion of gap G lies more distal to and radially outward from the flow path P than the wider portion at joint  35 . It will be appreciated that gap G may not be perfectly V-shaped, but this term is used herein with the understanding that gap G will generally approximate a V-shape in cross-section. Depending on the manufacturing process, and the type of material or product being transported in the piping system, debris may accumulate in gap G, and this accumulation may be undesirable, particularly for a lined piping system. 
     With continuing reference to  FIGS. 3 and 4 , gap G is filled in one embodiment by inclusion of a profiled annular gasket  40  having a complementary V-shaped portion which extends circumferentially in gap G. Preferably, gasket  40  is continuous in structure forming an unbroken ring-shaped element that is configured and adapted to fill gap G. With additional reference to  FIGS. 7 and 8 , gasket  40  includes an inner portion  41  disposed in contact with the two generally convex liner end surfaces RI on inner surfaces  13  and  23  of inner liners  12  and  22 , respectively, when installed. In one embodiment, inner portion  41  of gasket  40  has a generally triangular or V shape, which progressively narrows or tapers in width in a radial direction away from the interior  30  to the exterior  31  of the piping, wherein the gasket  40  is dimensioned and toleranced to approximately “match” or align with the adjacent surfaces. 
     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  FIGS. 5 and 6 , inner gasket face  43  may have a convex shaped surface in profile to produce a venturi effect for increasing flow velocity and clean sealing of the mating area between the gasket and interior  30  of piping sections  10 ,  20 . Accordingly, when a convex shaped gasket face  43  is provided, the inside diameter of gasket  40  will be slightly less than the inside diameter Di of piping sections  10  and  20 . 
     Gasket  40  further includes an outer portion  42  that is disposed opposite inner portion  41  as shown in  FIGS. 4 ,  6 ,  7 , and  9 . In one embodiment, outer portion  42  may be generally rectangular in cross-sectional profile and may be defined as beginning where the tapered sides  46 ,  47  of inner portion  41  end and become generally parallel to each other. Outer portion  42  is positioned toward the exterior  31  of piping sections  10 ,  20  at flanges  15 ,  25 , and does not have portions in contact with flow path P unlike inner portion  41 . Preferably, outer portion  42  extends outward to a radial distance at least equal to or greater than flared radial liner portions  19 ,  29  so as to securely compress and retain gasket  40  between the coupled flanges  15 ,  25  when drawn together. 
     Referring to  FIGS. 4 and 7 , inner portion  41  of gasket  40  has an axial width Wi and outer portion  42  has an axial width Wo. Preferably, the maximum width of Wi is larger than the maximum width of Wo to correspond with the general V-shaped configuration of gap G. Accordingly, in a preferred embodiment, gasket  40  becomes progressively narrower in width in a radially outward direction from the interior  30  of piping sections  10 ,  20  to the exterior  31  of the same. The widest portion of gasket  40  is therefore disposed closest to inner surfaces  13  and  23  of pipe sections  10  and  20  adjacent to the flow path P. 
     With continuing reference to  FIGS. 4 and 7 , gasket  40  further includes a pair of axially spaced-apart radial sides  46  and  47  formed along inner portion  41  and outer portion  42 . In one embodiment, sides  46 ,  47  converge towards each other along inner portion  41  and are disposed in parallel relation to each other along outer portion  42  as shown in  FIG. 7 . Sides  46  and  47  define a pair of spaced-apart annular sealing edges  48 ,  49  that extend circumferentially along the inner diameter of pipe sections  10 ,  20  when the gasket  40  is mounted in flanged joint  35 . As shown, for example, in  FIG. 4 , sealing edges  48 ,  49  engage and mate with inner surfaces  13 ,  23  of liners  12 ,  22 , respectively, on opposite sides of gasket  40  to form a seal in the interior  30  of pipe sections  10 ,  20  and to provide a smooth transition between inner surfaces  13 ,  23  at the joint. Accordingly, in one embodiment, sealing edges  48 ,  49  define annular line contact between gasket  40  and inner surfaces  13 ,  23  on the interior  30  of the piping to seal flanged joint  35 . The adapted detailed design and configuration of any particular gasket  40  would preferably be dimensioned and toleranced to appropriately “match” the adjacent surfaces. 
     In a further embodiment, with reference to  FIGS. 3-4  and  7 - 8 , sides  46 ,  47  of gasket  40  each further define a respective annular axial side surface  44 ,  45  that is configured and adapted to receive and engage the two generally convex liner end surfaces R 1  on inner liners  12 ,  22 . In one embodiment, side surfaces  44  and  45  preferably face in opposite axial directions. In one embodiment, side surfaces  44 ,  45  are preferably formed as recesses in each side  46 ,  47  of gasket  40 , and more preferably may be generally concave in shape as shown. Side surfaces  44 ,  45  have a radius of curvature R 2  selected to complement and approximate the shape or radius of the mating liner end surfaces R 1  of each radial flange liner portion  19  and  29 . It will be appreciated by those skilled in the art that the radius of curvature of R 2  of side surfaces  44 ,  45  need not exactly match the radius or shape of end surfaces R 1  of the flange liners  12 ,  22  since the gasket  40  and/or the liners may be compressible and deformable to a certain degree depending on the types of materials selected for the gasket and liners. In other embodiments to be further described herein with reference to  FIG. 9 , side surfaces  44 ,  45  may have other suitable cross-sectional shapes such as angular-shaped recesses to complement the shapes of the mating convex liner end surfaces. Thus the invention is not limited by the shape of side surfaces  44 ,  45  as described by the exemplary embodiments set forth herein. 
     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. 
       FIG. 9  shows an alternative embodiment of a flanged joint  50  for use in a piping assembly. In  FIG. 9 , a common angled or chamfered end preparation has been used in place of the more rounded pipe end prep shown in  FIGS. 3 and 5 . When liners  12 ,  22  are applied to the interior of piping sections  11 ,  21 , an angled convex liner end surface R 3  is formed in liners  12  and  22 , as shown in  FIG. 9 , which generally approximates the shape of the piping end chamfer. Accordingly, a profiled gasket  52  is provided having complementary angled-shape recessed side surfaces  51 ,  53 . Alternatively, depending on the degree of the angles used for angled convex liner end surface R 3 , other gasket configurations such as gasket  40  as shown in  FIG. 7  for example may be used depending on whether the gasket and/or liners  12 ,  22  are made of sufficiently pliable material to deform and create an adequate pressure seal at the flange joint. 
       FIG. 10  shows an alternative embodiment of a commonly used piping assembly in the form of a flanged lap joint  100  with loose lap joint rotating flanges  150 ,  250 . Piping sections  10 ,  20  are generally the same as shown, for example, in  FIGS. 3 and 4 . However, outer pipes  11 ,  21  are terminated with outward, radially-extending flared pipe ends  110 ,  112 . Inner liners  12 ,  22  are flared or formed radially outward over the flared pipe ends  110 ,  112 . Liners  12 ,  22  are flared and formed to extend radially-outward along the flared pipe ends  110 ,  112  as shown. The joint  100  is formed when flared ends  110 ,  112  of piping sections  10  and  20  are abutted, which also forms a generally triangular or V-shaped gap G therebetween. Profiled gasket  40  according to principles of the present invention is disposed between flared pipe ends  110 ,  112  and in gap G to reduce or preferably eliminate any dead space. The lap joint flanges  150 ,  250  shown allow the flanges to be conveniently rotated to a desired position before tightening the flange bolting (not shown) for convenient assembly and disassembly of piping sections  10 ,  20 . 
     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.