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  • Users: SD12
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  1. SD12

    General Flange Design.

    Thank you.
  2. SD12

    External Pressure Stiffner Ring

    Well, if fatigue is the issue, you shouldn't weld anything on top of the governing weld. Such complex weldment detail creates stress discontinuities that is difficult to analyse.
  3. SD12

    General Flange Design.

    Yes, it does. And I can see it clearly when the dead end or blind flange is in place. When they are not, even in the vicinity of the flange, the doubts arise. Thanks a lot for your help.
  4. SD12

    General Flange Design.

    Hello Mike. I understand your thought. But, what if we have 3 pipes, two of the them have blind flanges/dead ends at their respective ends. The pipe in the middle doesn't have any. Only flanged connections to pipe 1 and pipe 3. Those flanges (of the middle pipe 2) doesn't support any dead end...
  5. SD12

    General Flange Design.

    Hello. Consider a flanged connection subjected to the internal pressure only. Metal-to-metal contact with the O-ring. No other loads and temperature variations are present. Both flanges are welded to the pipes of the infinite length, i.e. there is no blind flange or dead end in the visinity of...
  6. SD12

    External Pressure Stiffner Ring

    Hello. You should never weld anything on the governing welds. There must be a distance between the center line of the butt weld and the next structural element (nozzle, ring, stiffener and so on).
  7. SD12

    Coaxiality tolerance for the welded structures

    Hello. I am trying to figure out what is the realstic value for the tolerance zone that can be obtained for the welded structure of this type. To me, even Ø0.1 looks challenging to get.
  8. SD12

    Coaxiality tolerance for the welded structures

    Yes. But my question is about that Ø0.01 tolerance value. Is this value realistic for a welded structure? This part isn't made by machining.
  9. SD12

    Coaxiality tolerance for the welded structures

    Hello. Would you please advice me about the admissible tolerance that controlls coaxiality of two cylinders welded to the steel plate. See the picture attached.
  10. SD12

    EN 13445-5: Equation 5.4.2 - The number of equivalent full pressure cycles

    I actually haven't seen this sentence. I have the standard issue from 2015. Thank you. Are there any worked examples for chapters 17 and 18?
  11. SD12

    EN 13445-5: Equation 5.4.2 - The number of equivalent full pressure cycles

    Hello! I have made a calculation of the number of equivalent full pressure cycles and my result is far more than 500 cycles. What is the procedure then? Should I take the number of equivalent full pressure cycles and compare it to FAT 100 S-N curve? Or it is more complicated than that? Do we...
  12. SD12

    EN 13445-3 Flange design - Assembly conditions vs Operating conditions

    @CuMo, I do agree with the safety concerns. But if there is a metal to metal flange, the assembly condition loads makes no sense. There is no way, in my opinion, for flange to fail. I am talking specifically about this eqaution: W=0.5*(Amin + A)*f (look at attached picture). Then this load is...
  13. SD12

    EN 13445-3 Flange design - Assembly conditions vs Operating conditions

    Thank you for information. I have written some questions but by some reason my reply went to the admins for some kind of controll - strange. If my reply isn't here by tomorrow, I will write it down one more time. Sergey
  14. SD12

    EN 13445-3 Flange design - Assembly conditions vs Operating conditions

    Hello! I have a question: What is the purpose of the moment for assembly conditions? To calculate stresses and thickness of a flange we are using moments for operating conditions. Moment for assembly conditions just adds confusion during calculation and is urealistic huge compared to operation...
  15. SD12

    Structural design of the Francis turbine rectangular draft tube with circular corners

    Yes, it probably will. But to asses the stresses in knuckles between the segments is the issue.
  16. SD12

    Structural design of the Francis turbine rectangular draft tube with circular corners

    Hello. No, I do not use the ASME code. EN 13445-3 is preferable but it has no stress assesment procedure as far as I know.
  17. SD12

    Structural design of the Francis turbine rectangular draft tube with circular corners

    Hello! I am trying to figure out how to perform a structural analysis of the rectangular draft tube to a Francis turbine subjected to internal pressure. I would like to know if there are any rules or codes or theory books that gives an introduction to this problem. There are two issues: -...
  18. SD12

    Kv flow coefficient

    Hello. I try to understand the following equation: Kv = Q / sqrt(delta p), whre "Kv" is in m^3/s, "Q" is in m^3/s and "delta p" is in MPa (or bar). If we divide flow (m^3/s) by the square root of pressure difference (MPa), how do we get the value of Kv to be in m^3/s? Please, give me an...
  19. SD12

    Ball and Butterfly valve design in application for Hydropower industry

    honza1801 Thank you for reply and comprehensive explanation. Best regards, Sergey
  20. SD12

    Hydropower valves design

    Hello. I am interested in design of the ball and butterfly valves that used in hydropower industry. Such valves installed in front of the turbines in hydropower plants. Which standards and/or literature describes the following: Stress analysis of the valve housing, counterweight design and...

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