Abstract:
A radial wedge flange clamp comprising a pair of flanges each comprising a plurality of peripheral flat wedge facets having flat wedge surfaces and opposed and mating flat surfaces attached to or otherwise engaged with two elements to be joined and including a series of generally U-shaped wedge clamps each having flat wedge interior surfaces and engaging one pair of said peripheral flat wedge facets. Each of said generally U-shaped wedge clamps has in its opposing extremities apertures for the tangential insertion of bolts to apply uniform radial force to said wedge clamps when assembled about said wedge segments.

Description:
The United States of America may have certain rights in this invention under Management and Operating Contract No. DE-AC05-84ER 40150 from the Department of Energy. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a device for making quick and reliable connection and disconnection of metal seal flanges. 
     BACKGROUND OF THE INVENTION 
     The mating surfaces of conventional, commercial wedge flange clamps that use flat or conical wedges that apply axial force to a conical shaped flange do not make full surface contact over the entire range of motion of the clamp. Thus, these clamps are not able to generate the high force needed to achieve tight metal to metal seals. The most common of such wedge flange clamps are identified as band clamps, hinged clamps and chain clamps. In each of these prior art clamps, a band, a hinged peripheral structure or a peripheral chain is used to force a flat or conical wedge clamping mechanism against and over a conical shaped flange. While such devices provide useful clamps each is subject to certain limitations. 
     For example, in the case of the band and hinged clamps, full surface contact is attained in only at a single point radial position. At other radial positions, the contact reverts to one or two line contacts that are subject to high friction and galling. In the chain clamp, full surface contact does not exist over the entire width of the chain segments but only at points at approximately the midpoint of the chain segment where they are in radial contact with the conical wedge. 
     Generation of the high axial forces needed to attain a tight metal to metal seal is only possible when full surface contact exists continuously between a flat wedge and a wedge shaped flange at every radial position. 
     It would therefore be highly desirable to have a wedge flange clamp that achieves full surface contact between a flat wedge and a wedge shaped flange over the entire available surface of both such elements through their entire range of motion. 
     OBJECTS OF THE INVENTION 
     It is therefore an object of the present invention to provide an improved interdependent wedge element flange and clamp system that maintains full surface contact between flat wedge clamp segments and matching flat wedge shaped flange facets. 
     It is another object of the present invention to provide such an improved clamp that is useful in tight physical space installations where axial installation and wrenching of axially disposed bolts or other similar fasteners is difficult or undesirable. 
     SUMMARY OF THE INVENTION 
     The radial wedge flange clamp of the present invention comprises a pair of flanges each comprising plurality of flat male peripheral wedge facets attached to or otherwise secured about two elements to be joined and a series of flat female wedge clamps each engaging one pair of said flat peripheral wedge facets and having in their opposed extremities apertures for the tangential insertion of bolts to apply uniform radial force to said wedge clamps thereby forcing the flat surfaces of said flat female wedge clamps against said flat surfaces of said wedge facets when said bolts are tightened. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of the essential elements of the radial wedge flange clamp of the present invention. 
     FIG. 2 is a partially phantom plan view of the radial wedge flange clamp of the present invention in its closed or tightened position. 
     FIG. 3 is a side view of an assembled radial wedge clamp of the present invention. 
     FIG. 4 is a cross sectional view along the line A—A of FIG.  2 . 
     FIG. 5 is an exploded view of an alternative embodiment of the radial wedge clamp of the present invention. 
     FIG. 6 is a cross-sectional view of the assembled radial wedge clamp of FIG.  5 . 
     FIG. 7 is a partially phantom view of an alternate preferred embodiment of the radial wedge clamp of the present invention. 
    
    
     DETAILED DESCRIPTION 
     Referring now to FIGS. 1 and 2, radial wedge clamp system  10  of the present invention comprises a pair of mating flanges  11  and  13  each comprising a plurality of peripheral flat wedge facets  12   a - 12   f  and  14   a - 14   f  integrally formed, attached to or secured about a pair of elements  18  and  20  which are to be joined by a metal to metal seal  44 , and an equal plurality of female radial wedge clamps  16   a - 16   f.  Each of wedge facets  12   a - 12   f  and  14   a - 14   f  has a flat mating surface  22   a - 22   f  and  24   a - 24   f  and a flat wedge shaped surface  26   a - 26   f  and  28   a - 28   f  respectively. Each of female radial wedge clamps  16   a - 16   f  is generally U-shaped and has wedge shaped inner upper surfaces  30   a - 30   f  and wedge shaped inner lower surfaces  32   a - 32   f  designed and sized to engage and compress against flat wedge shaped surfaces  26   a - 26   f  and  28   a - 28   f  respectively when female radial wedge clamps  16   a - 16   f  are engaged over a pair of peripheral flat wedge facets  12   a - 12   f  and  14   a - 14   f  after engagement and alignment of flat mating surfaces  22   a - 22   f  and  24   a - 24   f.  As described to this point radial wedge clamp  10  is quite similar in structure to prior art chain clamp segments. The principal distinction between the clamp segments of the prior art and those of the instant invention lies in the method and mechanism used to secure and tighten the radial wedge clamp segments about the distinctive individual flange facets to complete the radial wedge flange clamp system  10 . 
     According to the present invention, each of radial wedge clamps  16   a - 16   f  is provided with a pair of apertures  34   a - 34   f  and  36   a - 36   f.  Apertures  34   a - 34   f  are sized to receive bolts  38   a - 38   f  (shown in FIG. 2) and in the assembled configuration shown in FIG. 2 lie in registration. By “in registration” is meant that oppositely numbered and neighboring apertures abut and align with each other. For example, aperture  34   a  meets aperture  36   b;  aperture  34   b  meets aperture  36   c,  etc in the assembled configuration shown in FIG.  2 . Apertures  34   a - 34   f  include recessed portions  40   a - 40   f  (see FIG. 2) designed to receive the oversized heads  39   a - 39   f  of bolts  38   a - 38   f  and smooth bore portions  42   a - 42   f  (see FIG. 2) that permit passage of bolts  38   a - 38   f  without engagement. Apertures  36   a - 36   f  on the other hand may be but are not necessarily threaded to receive and engage threads  37   a - 37   f  on bolts  38   a - 38   f  that have been inserted through apertures  34   a - 34   f  and enter apertures  36   a - 36   f.  In this arrangement, concurrent or ordered (as described below) tightening of bolts  38   a - 38   f  causes radial wedge clamps  16   a - 16   f ) specifically, flat surfaces  30   a - 30   f  and  32   a - 32   f ) to compress against flat wedge shaped surfaces  26   a - 26   f  and  28   a - 28   f  forcing flat mating surfaces  22   a - 22   f  and  24   a - 24   f  into intimate and full contact or against seal  44  when used. The plurality of strategically placed tangentially oriented bolts  38   a - 38   f  apply great and uniform radial force to a system of wedge elements while never compromising the intrinsic tendency of the wedge elements to maintain full surface contact. The mechanical advantage obtained through the use of threaded fasteners is far superior to and more complete than those demonstrated by the prior art such clamps discussed above that provide less radial force that is confined to single or intermittent pressure points about individual wedge elements. Bolt heads  39   a - 39   f  may of course have a variety of tightening mechanisms such as slot heads, Phillips heads or Allen type heads for tightening. According to an alternative preferred embodiment of the present invention, apertures  36   a  through  36   f  are smooth bored and nuts  90   a - 90   f  are used to engage threads  37   a - 37   f  on bolts  38   a - 38   f  as they exit apertures  36   a - 36   f  (See FIG.  7 ). Bolts  38   a - 38   f  are gradually tightened in ¼ turn increments in the torquing sequence a, c, e, b, f, d which is a conventional and accepted procedure for tightening a series of bolts such as those described hereinabove to obtain even and optimum tightening thereof. 
     Referring now to FIGS. 5 and 6 that depict an alternative preferred embodiment of the radial wedge clamp of the present invention, radial wedge clamp  10  includes all of the essential elements previously described and additional members that simplify installation, and allow for the use of virtually any seal configuration. As shown in FIG. 5, this alternative embodiment of radial wedge clamp  10  includes a pair of mounting flanges  50  and  52  comprised of main body portions  54  and  56  and shoulder portions  58  and  60  integrally formed therewith and extending radially therefrom. Main body portions  54  and  56  are individually attached to mating ends of two tubular members  53  and  55 , best shown in FIG. 6, such that shoulder portions  58  and  60  extend away from mating surfaces  62  and  64  of main body portions  54  and  56 . Mating ring  66  that includes a central aperture  63  of a diameter to engage the outer peripheries  67  and  68  of main body portions  54  and  56  and outer periphery  65  of seal  44  when mating surfaces  62  and  64  are addressed and brought into contact with each other, in the case of direct metal to metal sealing, or intermediately disposed seal or gasket  44 . In this configuration, apertures  15  and  17  of mating flanges  11  and  13  are disposed or engaged about the outer peripheries  70  and  72  of shoulder portions  58  and  60 , best seen in FIG.  6 . The presence of mating ring  66  serves as a means to retain the entire assembly in a unitary and controllable configuration as mating flanges  11  and  13  as well as female radial wedge clamps  16   a - 16   f  are brought into engagement with flat wedge facets  12   a - 12   f  and  14   a - 14   f  as described hereinabove. As best seen in FIG. 6, mounting flanges  50  and  52  preferably include knife edges  74  and  76  that “cut” into seal  44  when radial wedge clamp  10  is tightened as described above. While the presence of knife edges  74  and  76  is not critical to the successful application of the radial wedge clamp of the present invention in all environments, it is particularly useful in the case of ultra high vacuum joints where complete, intimate and pressure resistant contact is required. Knife edges  74  and  76  may be substituted with whatever feature is required to accept any number of different seal types such as metal O-rings, wire rings and sharp edged seals. 
     Radial wedge clamp  10  and all of its various elements can be fabricated from any number of materials. Most commonly, such clamps are made of steel or some other appropriate metal, by polymers; for example engineering polymeric materials may also be used. Similarly, hybrid clamps wherein the wedge shaped flanges  11  and  13  are located on a polymeric pipe or other structure, radial wedge clamps  16   a - 16   f  may be fabricated from steel or some other metal. 
     As will be obvious to the skilled artisan, seal  44  as shown in FIG. 1 is preferably used between flat surfaces  22   a - 22   f  and  24   a - 24   f.  In ultra high vacuum situation, for example at pressures of less than about 10 −6  Torr, seal  44  will comprise a relatively soft or malleable metal such as for example copper that can be deformed by knife edges  74  and  76  upon tightening of bolts  38   a - 38   f  as described hereinabove. Cryogenic conditions might also require such metal seal joints. Of course, in less demanding applications, seal  44  may comprise any of the more commonly used rubber or other seal or gasket materials. In many applications, due to the enhanced ability to apply elevated levels of radial pressure to radial wedge clamps  16   a - 16   f,  it may be unnecessary to use seal  44 , since direct metal to metal or polymer to polymer, in the case of polymeric wedge flanges, may be adequate to provide the required seal. 
     The number of flange facets  12   a - 12   f  and  14   a - 14   f  and wedge clamps  16   a - 16   f  is, of course largely a matter of design choice. The use of a hexagonal or six-sided arrangement as depicted in the drawings provides an optimized structure from an assembly and engineering standpoint and is therefore preferred. 
     As the invention has been described, it will be further apparent to those skilled in the art that the same may be varied in many ways without departing from the spirit and scope of the invention. Any and all such modifications are intended to be included within the scope of the appended claims.