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电接点开关腔体
耐压数据及计算方法
 
For the convenience of piping engineers, the following pages show the allowable pressure rating at temperature of various piping materials including Stainless Steel Type 304 and 316 in sizes ½” through 24” in popular wall schedules.   
    Stress values shown at various temperatures are as given in Appendix A of ANSI B31.3-Code for Pressure Piping for Petroleum Refinery Piping.
The allowable pressure ratings have been calculated from the basic formula given in ANSI B31.3 as
             
follows:P= 2SET/D
                 
Where:  
T =  design thickness of the pipe (121/2% less than the nominal wall thickness of any given pipe size)  
P = internal design pressure, PSIG  
D = outside diameter of pipe, inches  
S = allowable stress for materials at service temperature, PSI  
E = 1.0 for seamless pipe and   0.8 for welded pipe.
 
The computations shown are a preliminary guide for determining the proper wall thickness and are not to be considered a substitute for various Codes for Pressure Piping.
 
The user should refer to the applicable Code for Pressure Piping covering the design and material limitations and rules. The particular Code should be reviewed before final design thickness is determined. Depending upon the general service for which the piping system is intended, one of the following may be applicable:
  
• ASME-Section I-Power Boilers
• ASME-Section III-Nuclear Power Plant Components
• ASME-Section VIII-Pressure Vessels
• ANSI B31.1-Power Piping  
• ANSI B31.3-Petroleum Refinery Piping
• ANSI B31.5-Refrigeration Piping
 
The user is cautioned that the stress values shown in the various Codes do vary. For example, the stress values used in our calculations are not the same as noted in ANSI B31.1. Limitations on maximum temperature for materials may also vary with each Code.
 
It should be noted that all calculations are based on a specific piping material. Other materials may be used in the manufacture of butt weld fittings.