Pressure Design of Metallic Components

Branch Welds These welds eliminate the purchase of tees and require no more weld metal than tees (Fig. 10-127). If the branch approaches the size of the run, careful end preparation of the branch pipe is required and the run pipe is weakened by the branch weld. See subsection Pressure Design of Metallic Components Wall Thickness for rules for reinforcement. Reinforcing pads and fittings are commercially available. Use of the fittings facilitates visual inspection of the branch weld. See subsection Welding, Brazing, or Soldering for rules for welded joints. 

The SE values in Table 10-49 are equal to the basic allowable stresses in tension S multiplied by a quality factor E (see subsection Pressure Design of Metallic Components Wall Tliick-ness"). The design stress values for bolting materials are equal to die basic allowable stresses S. The stress values in shear shall be 0.80 times the allowable stresses in tension derived from tabulated values in Table 10-49 adjusted when applicable in accordance widi Note 13. 8tress values in bearing shall be twice those in shear. 

Pressure Design of Metallic Components External-pressure stress evaluation of piping is the same as for pressure vessels. But an important difference exists when one is establishing design pressure and wall thickness for internal pressure as a result of the ASME Boiler and Pressure Vessel Codes requirement that the relief-valve setting be not higher than the design pressure. For vessels this means... 

Pressure Design of Metallic Components Wall Thickness. 10-103... 

Internal resistive heating, where a miniature heater is placed inside the pressure cell, requires considerably less power than external heaters. A number of internal heater designs in which the heating element is either attached to the gasket [203], is part of the gasket [204], or is inside the sample chamber itself [205-207] have been described. Care must be taken to ensure that the heater is electrically insulated from the gasket and other metallic components. Resistively heated cells can attain temperatures as high as 2,700 K [207], particularly if both internal and external heaters are employed. 

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