Abstract:
A flange designed for gasket compression control. Flange may have a hollow inner portion surrounded by a substantially flat outer lip, in which there may be a number of boltholes. Flange may have at least one mechanical stopper extending outward from it in a position unobstructed by the gasket; there may be mechanical stoppers on either side of the gasket, separated into “external” and “internal” mechanical stoppers. Mechanical stopper may be of a height equal to or greater than the lower bound of the minimum safe range of the gasket, or alternatively may be paired with a mechanical stopper on another flange such that when the two are mated the combination of the two exceeds the minimum safe range. This value may typically be around twenty to thirty-five percent of the gasket&#39;s uncompressed thickness. Optionally, the space between the external and internal mechanical stoppers may be grooved to further serve as a guide.

Description:
BACKGROUND 
       [0001]    In a variety of mechanical applications, gaskets are used to create static seals between stationary members of a mechanical assembly and used to maintain that seal under the normal operating conditions of the mechanical assembly. Often, these conditions vary, and the gasket may be exposed to a wide range of temperatures, pressures, or hazards. 
         [0002]    Improper placement of a gasket can lead to minor or even major problems in the remainder of the mechanical assembly. For example, if a gasket placed around a pipe is overtightened, part of the seal may intrude into the pipe, which may substantially increase the wear on the inner rim of the gasket; this may develop to the point where large portions of the gasket are being worn away, subjecting the system to contamination from the torn-away gasket material. Conversely, if the gasket is undertightened, it may be ineffective at sealing the flange or other mechanical assembly and the seal may leak; this may in turn present a major hazard to bystanders if the contents of the pipe are toxic or otherwise dangerous. 
         [0003]    Various solutions exist for controlling the compression on a gasket in order to keep it within acceptable bounds and avoid these problems. If a flat gasket design is used, a user may have to periodically check the seal of the gasket, and, if necessary, retorque the compression on the gasket to the proper value or replace the gasket entirely. The initial inexpensiveness of the flat gasket design means that greater expenditure can be spent on maintenance of the seal without the design becoming uncompetitive. However, given that such designs may be prone to “seepage” and “weepage,” as well as to sudden ruptures, flat gaskets are generally limited in their application. 
         [0004]    Another common solution is to use a grooved flange design paired with a gasket shaped to fit in the groove during normal use; this gasket might take the form of a circular ring or O-ring. One major problem with this solution, however, is that while the O-ring gaskets themselves may be relatively inexpensive and simple to manufacture, using them to seal a particular flange connection requires the use of more material in the flange connection, precise machining of the flange groove, and time-consuming assembly, making O-ring seals rather costly to put into place despite their low apparent price. Other problems may also develop on account of the use of an O-ring design. For example, a large portion of the surface of the O-ring design may be exposed to fluid attack, which may be problematic if the fluid is caustic or damaging to the O-ring material. Pressure fluctuations may also cause damage to the O-ring. Stress concentrations or even stress cracking may also develop from the flange groove, potentially resulting in early failure of the flange or piping system. 
         [0005]    Alternatively, a gasket may be molded precisely to the contours of the flange it is to be placed on. This may offer superior performance but may be expensive and complicated to implement. Users may not readily have access to custom molded gaskets that fit the particular flanges that they are using, and may have to specially order or make them. If every flange has its own custom-made gasket, this may also increase inventory and storage requirements; the user may have to keep a spare gasket for every flange to be sealed instead of just a few spares that may be used interchangeably on a larger number of flanges. 
       SUMMARY 
       [0006]    A flange designed for gasket compression control may be described. Flange may have a hollow inner portion surrounded by a substantially flat outer lip, in which there may be a number of boltholes. Flange may have at least one mechanical stopper extending outward from it in a position unobstructed by the gasket; there may be mechanical stoppers on either side of the gasket. Mechanical stopper may be of a height equal to or greater than the lower bound of the minimum safe range of the gasket, or alternatively may be paired with a mechanical stopper on another flange such that when the two are mated the combination of the two exceeds the minimum safe range. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Advantages of embodiments of the present invention will be apparent from the following detailed description of the exemplary embodiments. The following detailed description should be considered in conjunction with the accompanying figures in which: 
           [0008]      FIG. 1  shows an exemplary embodiment of a mechanical stopper used for gasket compression control. 
           [0009]      FIG. 1A  shows a detail view of an exemplary embodiment of a mechanical stopper used for gasket compression control. 
           [0010]      FIG. 2  shows a three-dimensional view of an exemplary embodiment of a mechanical stopper used for gasket compression control. 
           [0011]      FIG. 2A  shows a detail view of an exemplary embodiment of a mechanical stopper used for gasket compression control. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    Aspects of the present invention are disclosed in the following description and related figures directed to specific embodiments of the invention. Those skilled in the art will recognize that alternate embodiments may be devised without departing from the spirit or the scope of the claims. Additionally, well-known elements of exemplary embodiments of the invention will not be described in detail or will be omitted so as not to obscure the relevant details of the invention. 
         [0013]    As used herein, the word “exemplary” means “serving as an example, instance or illustration.” The embodiments described herein are not limiting, but rather are exemplary only. It should be understood that the described embodiments are not necessarily to be construed as preferred or advantageous over other embodiments. Moreover, the terms “embodiments of the invention”, “embodiments” or “invention” do not require that all embodiments of the invention include the discussed feature, advantage or mode of operation. 
         [0014]    Referring now to exemplary  FIG. 1 , a flange  100  suitable for gasket compression control may be described. Flange  100  may have a hollow inner portion and a flared, substantially flat outer lip, and may be of any shape desired; for example, it may be round, square, rectangular, or another shape. Flared, substantially flat outer lip may have a number of boltholes by which flange  100  may be mated to another flange  100 , or may have another structure suitable for mating to another flange  100 . Flange  100  may accommodate a gasket  104  that extends contiguously around the perimeter of the flange  100 , and may have a number of mechanical stoppers  102 ,  106  suitable to restrict the compression of the gasket  104  when the flange  100  is made part of a flange connection. Mechanical stoppers  102 ,  106  may be spaced at appropriate locations around the perimeter of the flange  100 , for example at regularly spaced locations or near key points like the corners of the flange  100 . Other flange embodiments  100  and other mechanical stopper placement  102 ,  106  may be envisioned; for example, if the flange is round or rounded, mechanical stoppers may be placed radially, or as desired. 
         [0015]    Mechanical stoppers  102 ,  106  may be part of the design of the flange  100 , and may be produced along with the flange  100  as a single part by a method appropriate to produce the flange  100 , for example by forging. According to an alternative embodiment, mechanical stoppers  102 ,  106  may be securely joined or fastened to the flange later on, for example by welding, soldering or adhesive bonding. 
         [0016]    According to an exemplary embodiment, mechanical stoppers  102 ,  106  may be separated into mechanical stoppers placed externally from the gasket  102  (“outer mechanical stoppers”) and mechanical stoppers placed internally from the gasket  106  (“inner mechanical stoppers”). According to some embodiments, only outer mechanical stoppers  102  may be employed, or only inner mechanical stoppers  106  may be employed, or both, as desired. According to other embodiments, a single internal or external mechanical stopper  102 ,  106  extending around the perimeter of the flange  100  may be used in place of a multiplicity of internal or external mechanical stoppers  102 ,  106 , as desired. 
         [0017]    Mechanical stoppers  102 ,  106  may extend from the surface of the flange  100  in portions not covered by the gasket  104 . According to an exemplary embodiment, mechanical stoppers  102 ,  106  may extend from the surface of the flange  100  for a distance that allows the flange  100  to be compressed but which does not allow the gasket  104  to be compressed outside of the specified safe range for a particular gasket  104 . Depending on the gasket  104  to be used, the specified safe range may vary; according to some embodiments, the minimum safe range may be between twenty percent and thirty-five percent of the gasket&#39;s uncompressed width, depending on factors like the gasket  104  size and material used. Other gaskets  104  may have minimum safe ranges outside of these values, and different sizes of mechanical stoppers  102 ,  106  may be used. Different shapes of mechanical stoppers  102 ,  106  may also be used; for example, according to some embodiments, mechanical stoppers  102 ,  106  may be rounded, may be rectangular, may be curved, or may be any other shape desired. According to one exemplary embodiment, mechanical stoppers  102 ,  106  may be added to only one flange  100  in a flange connection; according to an alternative embodiment, mechanical stoppers  102 ,  106  may be added to both flanges  100  in a flange connection. According to the second embodiment, mechanical stoppers  102 ,  106  may be sized to be approximately half of the width of the lower bound of the minimum safe range rather than approximately the width of the lower bound of the minimum safe range; this may ensure that when one flange  100  is mated to another in a flange connection, the flanges  100  are held apart by a distance approximately that of the lower bound minimum safe range of the gasket  104 . Alternate widths, such as the upper bound of the minimum safe range or another width, may also be used. 
         [0018]    According to another embodiment, mechanical stoppers  102 ,  106  may overlap with the gasket  104 ; for example, gasket  104  may be a flat-type gasket having a number of holes near the perimeter (such as boltholes), and mechanical stoppers  102 ,  106  may be placed approximately where those holes are located. Mechanical stoppers  102 ,  106  may be interspersed with boltholes, as desired. According to one exemplary embodiment, a flat-type flange gasket  104  may have eight boltholes evenly spaced around the perimeter of the flange gasket, and a flange design  100  with which it may be paired may have four bolts extending through the flange at the 0°, 90°, 180°, and 270° points, and may have four round mechanical stoppers  102 ,  106  approximately the same size as the boltholes at the 45°, 135°, 225°, and 315° points. According to an alternative embodiment, mechanical stoppers  102 ,  106  and boltholes may overlap; for example, the boltholes may have a raised edge, rim, or outer perimeter that extends from the surface of the flange  100 , such that when a flange connection is made the raised edges of the boltholes come into contact and prevent a flush connection between the two flanges  100  from being formed. The width of this gap between flanges  100  may be a function of the width of a standard gasket  104  and its maximum compressibility; for example, according to an embodiment in which the gasket  104  may be safely compressed to approximately twenty-five percent of its maximum width, the raised rims of the boltholes may each have a height of approximately fifteen percent of the width of the gasket  104 . This may ensure that when the two flanges are mated, a gasket  104  placed between them will not be compressed for more than the maximum level it may accommodate. Mechanical stoppers  102 ,  106  intended to be used on both parts of a mated pair of flanges  100  need not be the same uniform height; for example, if the mated pair of flanges  100  is intended to accommodate a gasket  104  with a minimum safe width of thirty-five percent of the gasket&#39;s uncompressed width, some of the mechanical stoppers  102 ,  106  may have a height of ten percent of the gasket&#39;s uncompressed width and some of the mechanical stoppers may have a height of twenty-five percent of the gasket&#39;s uncompressed width, such that when the two flanges  100  are paired the mechanical stoppers  102 ,  106  space the two flanges  100  apart by a combined total of thirty-five percent of the gasket&#39;s uncompressed width. Other combinations, such as one percent and thirty-four percent of the gasket&#39;s uncompressed width, may be envisioned; negative widths, effectively representing holes in the flange  100 , may also be envisioned and may allow the flanges  100  to interlock when mated. According to another embodiment, a similar interlocking effect between mechanical stoppers  102 ,  106  may be created by employing mechanical stoppers  102 ,  106  that do not have a bottom surface parallel to the surface of the flange  100 ; for example, the bottom surfaces of mechanical stoppers  102 ,  106  may be angled or curved. 
         [0019]    Alternatively, each flange  100  may have its own mechanical stoppers that extend for thirty-five percent of the gasket&#39;s uncompressed width, but the mechanical stoppers  102 ,  106  on each may be placed such that the two do not interfere with each other. For example, mechanical stoppers  102 ,  106  may be placed only on the right side of the flange  100 , such that when two such flanges  100  are paired, the mechanical stoppers  102 ,  106  may be on separate sides of the connection. 
         [0020]    Alternatively, no standard gasket  104  sizing may be used, and mechanical stoppers  102 ,  106  may be sized to the gasket  104  or otherwise adjusted to an appropriate size instead. For example, according to one exemplary embodiment, mechanical stoppers  102 ,  106  may not be securely fastened to the flange surface  100 , and may instead be held in place by bolts similarly to nuts or washers. 
         [0021]    Mechanical stoppers  102 ,  106  may be composed of different materials, or may be differently treated; for example, according to an exemplary embodiment wherein the center walls of the flange  100  are treated to resist corrosion and fluid wear, the inner mechanical stoppers  106  may be similarly treated but the outer mechanical stoppers  102  may not be. According to an alternative exemplary embodiment, the internal and external surfaces of the flange  100  may be composed of different materials; the mechanical stoppers  102 ,  106  may likewise be composed of different materials. 
         [0022]    Gasket  104  may be any type of gasket or seal. According to one exemplary embodiment, gasket  104  may be a flat-type gasket, and the outer mechanical stopper  102  and the inner mechanical stopper  106  may serve as guides for the gasket  104 . The outer mechanical stopper  102  and inner mechanical stopper  106  may be spaced apart by approximately the thickness of the gasket  104  such that the gasket  104  fits between them when put into place. Gasket  104  fit may be snug or may be loose, as desired; this may also depend on factors like the choice of gasket  104 , such as the choice of a flat gasket design over an O-ring gasket design. Gasket  104 , if flat, may be secured in place by a plurality of bolts that may also be used to tighten the flange  100 ; according to one exemplary embodiment, there may be a plurality of boltholes extending through the flange  100  and a number of boltholes extending through the gasket  104  in approximately the same distribution as on the flange  100 , such that bolts may be passed through the flange  100  and gasket  104  simultaneously and both secured in place. Other methods of securing may also be employed. 
         [0023]    According to an alternative embodiment, flange  100  may have a guide groove sized to accommodate a gasket  104 , and gasket  104  may be placed within or aligned with the guide groove, with mechanical stoppers  102 ,  106  then extending for a distance exceeding the lower bound of the minimum safe compression range of the gasket. The use of mechanical stoppers  102 ,  106  paired with a guide groove may allow for a shallower groove that requires less complicated machining to add; alternatively, guide groove may be added by another method, for example during the initial forging step or by chemical etching. The reduced need for complicated machining may in turn reduce the cost of producing the flange  100 . 
         [0024]    According to a third embodiment, an alternative method of holding the gasket  104  in place may be employed, or another method of sealing may be used. For example, the surface of the flange  100  may be coated with sealant, which may dry in the form of a seal; mechanical stoppers  102 ,  106  may then be used to ensure that there is not an excess amount of compression on the seal. 
         [0025]    Referring now to exemplary  FIG. 1A , a detail view  120  of flange  100  may be provided. Flange  100  may have a hollow inner portion and a flared, substantially flat outer lip, may have an outer mechanical stopper  102 , may have a gasket  104  or geometry accommodating the insertion of a gasket  104 , and may have an inner mechanical stopper  106 . According to one exemplary embodiment, inner mechanical stopper  106  may be a single solid piece that extends around the inner perimeter of the flange  100 , while a plurality of external mechanical stoppers  102  may be spaced around the outer perimeter of the flange  100 . The use of a single solid piece as the inner mechanical stopper  106  may have numerous advantages; for example, it can help ensure that the gasket  104  is properly positioned by providing a frame around which the gasket  104  may be stretched or otherwise positioned. Other embodiments of mechanical stoppers may be envisioned. 
         [0026]    Referring now to exemplary  FIG. 2 , a three-dimensional view of a flange  200  may be provided. Flange  200  may have a hollow inner portion and a flared, substantially flat outer lip, may have an outer mechanical stopper  202 , may have a gasket  204  or geometry accommodating the insertion of a gasket  204 , and may have an inner mechanical stopper  206 . 
         [0027]    Referring now to exemplary  FIG. 2A , a detail view  220  of flange  200  may be provided. Flange  200  may have a hollow inner portion and a flared, substantially flat outer lip, may have an outer mechanical stopper  202 , may have a gasket  204  or geometry accommodating the insertion of a gasket  204 , and may have an inner mechanical stopper  206 . 
         [0028]    The foregoing description and accompanying figures illustrate the principles, preferred embodiments and modes of operation of the invention. However, the invention should not be construed as being limited to the particular embodiments discussed above. Additional variations of the embodiments discussed above will be appreciated by those skilled in the art. 
         [0029]    Therefore, the above-described embodiments should be regarded as illustrative rather than restrictive. Accordingly, it should be appreciated that variations to those embodiments can be made by those skilled in the art without departing from the scope of the invention as defined by the following claims.