Alky-one gasket

Abstract

A method is provided for forming a gasket for sealing opposing flange surfaces of a pipe having corrosive fluid flowing therethrough. The method comprises defining a gasket profile incorporating a serrated profile core having a flange extending radially inward therefrom. A deformable pillow extends radially inward from the serrated profile core, to define a gasket intermediate portion about the flange, and a gasket inner portion radially inward from the flange. The deformable pillow material and thickness are selected such that upon compression to a thickness no less than the core thickness, the gasket inner portion exhibits a stress level sufficient to preclude corrosive liquid flowing through the pipe from passing radially outward beyond the gasket inner portion, and the gasket intermediate portion exhibits a stress level sufficient to preclude gas and liquid flowing through the pipe from passing radially outward beyond the gasket intermediate portion.

What is claimed is: 
     
         1 . A method of forming a gasket for sealing opposing flange surfaces of a pipe having corrosive fluid flowing therethrough, the gasket comprising:
 defining a gasket profile including a serrated profile core, the serrated profile core defining a core thickness and a core inner surface;   forming a flange extending radially inward from the core inner surface, the flange defining a flange length, a flange thickness and a flange inner surface;   forming a deformable pillow about the flange, extending radially inward from the core inner surface, inward beyond the flange, to define a gasket inner surface; and   the gasket defining an outer, high stress, fire resistant sealing zone about the serrated profile core, an intermediate stress gas/liquid sealing zone between the core inner surface and the flange inner surface, and an inner, low stress liquid sealing zone between the flange inner surface and the gasket inner surface.   
     
     
         2 . The method recited in  claim 1  wherein each sealing zone is formed to have a characteristic sealing stress level that is progressively higher from the inner sealing zone to the outer sealing zone. 
     
     
         3 . The method as recited in  claim 2  wherein the deformable pillow material is selected to be sufficiently deformable to seal imperfections in the opposing pipe flanges adjacent to the inner sealing zone. 
     
     
         4 . The method as recited in  claim 2  wherein when a defined bolt load is applied to the gasket the deformable pillow in the inner sealing zone is compressible to a minimum inner zone stress level to prevent corrosive liquid flowing the pipe from reaching the intermediate sealing zone. 
     
     
         5 . The method as recited in  claim 4  wherein when the defined bolt load is applied to the gasket the deformable pillow in the intermediate sealing zone is compressible to a minimum intermediate zone stress level to prevent corrosive liquid and gas flowing through the pipe from reaching the outer sealing zone. 
     
     
         6 . The method as recited in  claim 5  wherein when the defined bolt load is applied to the gasket the serrated profile core exhibits a stress that is equal or greater than a minimum gasket stress level. 
     
     
         7 . The method as recited in  claim 6  wherein the deformable pillow defines a pillow thickness and a pillow material. 
     
     
         8 . The method as recited in the  claim 4  furthering comprising the step of selecting the pillow material and the pillow thickness to provide a desired minimum inner zone stress level when the deformable pillow material in the inner zone is compressed to a thickness to no less than the core thickness. 
     
     
         9 . The method as recited in the  claim 5  furthering comprising the step of selecting the flange thickness to provide a desired minimum intermediate zone stress level when the intermediate zone is compressed to a thickness to no less than the core thickness. 
     
     
         10 . The method as recited in  claim 9  furthering comprising the step of regulating the flange thickness such that the minimum intermediate zone minimum stress level is no more than 21% of the gasket stress level. 
     
     
         11 . A method of forming a gasket for sealing between opposing flange surfaces of a pipe having a corrosive fluid flowing therethrough, the method comprising:
 defining a gasket profile incorporating a serrated profile core, the serrated profile core defining a core thickness;   forming a flange extending radially inward from the serrated profile core;   forming a deformable pillow extending radially inward from the serrated profile core, about the flange, to define a gasket intermediate portion, the deformable pillow further extending radially inward from the flange to a gasket inner surface, to define a gasket inner portion;   selecting a deformable pillow material and a deformable pillow thickness such upon compression of the gasket to a thickness no less than the core thickness, the gasket inner portion exhibits a stress level sufficient to preclude corrosive liquid flowing through the pipe from passing radially outward beyond the gasket inner portion, and the gasket intermediate portion exhibits a stress level sufficient to preclude gas and liquid flowing through the pipe from passing radially outward beyond the gasket intermediate portion.   
     
     
         12 . The method as recited in  claim 11  further comprising the step of regulating the radial length of the flange and the deformable pillow thickness such that upon application of a designated bolt load to the gasket, the serrated profile core exhibits a stress level that is equal to or greater than a minimum gasket stress level. 
     
     
         13 . A method of designing a sealing gasket for use between two connecting flanges of a pipe, the gasket defining a primary seal, an intermediate seal and an inner seal method comprising:
 selecting a pipe diameter and a bolt load;   selecting a minimum gasket primary seal stress level;   selecting a thickness of the primary seal;   forming a flange extending radially inward from the primary seal, the flange being enveloped by a deformable pillow material to define the gasket intermediate, the deformable pillow material extending radially inward from the flange to a gasket inner surface to define a gasket intermediate seal;   selecting a gasket inner seal minimum stress level that is sufficient to preclude liquid from passing through the inner seal;   selecting a gasket intermediate seal minimum stress level that is sufficient to preclude gas and liquid from passing through the intermediate seal;   selecting a material for the gasket inner seal; and   regulating a thickness of the inner seal to produce the gasket inner seal minimum stress level when the inner seal is compressed to a thickness substantially equal to the primary seal thickness.   
     
     
         14 . The method as recited in  claim 13  further comprising the step of regulating a thickness of the flange to regulate the stress level of the gasket intermediate seal, through which the flange extends. 
     
     
         15 . The method as recited in  claim 14  wherein the step of regulating the thickness of the flange comprises increasing the thickness of the flange to increase the minimum stress level on the gasket intermediate seal. 
     
     
         16 . The method as recited in  claim 15  further comprising the step of regulating the thickness of the flange to produce the gasket intermediate seal stress level when the intermediate seal is compressed to a thickness substantially equal to the gasket primary seal thickness. 
     
     
         17 . The method as recited in  claim 16  furthering comprising the step of regulating the thickness of the inner flange and of the gasket inner seal material such that upon application of the selected bold load to the gasket at least 80% of the gasket stress is applied to the primary seal. 
     
     
         18 . The method as recited in  claim 16  further comprising the step of regulating the thickness of the inner flange and thickness of the gasket inner seal material such that no more than 90% of the gasket stress is applied to the primary seal. 
     
     
         19 . The method as recited in  claim 13  wherein the sealing gasket is characterized by areas of progressively higher minimum sealing stress, extending radially outward from the gasket inner surface. 
     
     
         20 . The method as recited in  claim 13  wherein the connecting flanges define an inner surface portions having imperfections formed therein, and wherein the gasket inner seal is compressible to seal the imperfections.