Calculation of the equivalent pressure on pipe flanges caused by additional external loads
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In typical designs, the nominal pressure class of flanges is generally determined based on the internal pressure in the pipeline, the material of the flange, and the design temperature. Strictly speaking, the impact of additional external loads should also be taken into consideration. According to the formula on page 55 of SH/T3059-2012, external loads can be converted into equivalent pressure; however, the results obtained in this way are somewhat unexpected. I would appreciate any insights from those who are knowledgeable on this matter! Here is an example: For a DN50 steam pipeline with an internal pressure of 1.0 MPa and a concentrated load of 50 kG, where the load point is located 3000 mm away from the flange, the equivalent pressure Peq is calculated as 16M/(π*Dg3) = 16*3000*50*9.81/(3.14*923) = 9.6 MPa. The value of the equivalent pressure is much higher than the internal pressure; is there something wrong with this result?
Please feel free to speak up! How is Dg determined in the formula? It would be great if an example could be provided. Thank you!
As I understand it, Dg is the bolt hole spacing K
The Dg specified in the standards is the diameter of the circle at the center of force exerted by the gasket compression; I believe it might be the average of the inner and outer diameters of the gasket, but when I used this value to verify the calculation results presented in other published articles, the results did not match. That’s why I’m asking someone who knows more clearly.
I’d like to ask, how do you determine this Dg value? According to your calculation, you used 9.74 mm
The calculation of the flange torque M is based on the assumption of a 3-meter cantilever beam subjected to a concentrated load; this mechanical model is flawed – how could a steam pipe be under cantilever stress?