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Recent content by jalvarez

  1. jalvarez

    Parallel Relief Valves

    One of the potential problems is related with the analysis of contingencies and the possibility of chattering. As an example: Suppose the designer end up with a maximum flow for the worst contingency of 100, and the valve (and its spare, that was thought here only for maintenance reasons) was...
  2. jalvarez

    Normalized A-105 or 316L?

    Taking into account metengr comment, if I have a blind joint, I'll use the SS (but I haven't). We are using monel graphite joints.
  3. jalvarez

    Normalized A-105 or 316L?

    SnTMan We are using A-350 LF2 in all the job, but we need to stop this 6" line in a point. We only have at hand the two mentioned alternatives; to find a blind Ø6" #300 (or a cap) in LF2 is not so easy here. I'm curious -and surprised- now. What are the reasons to prefer the normalized A-105...
  4. jalvarez

    Normalized A-105 or 316L?

    We are doing a modification in a line carrying anhidrous Hydrogen Chloride. The original materials are ASTM A-333 Gr 6 for piping and A-350 LF2 or A-420 WPL6 for accesories. We are installing a low point in a Ø 6" line, and we need to install now a 6" blind flange there. Operating conditions...
  5. jalvarez

    Branch connections practices

    JohnBreen I think that I quoted correctly the code, in the necessary extent to be understood. As the discussion went in the direction I liked, fine. One step ahead: The usage of half couplings as branch connections is covered by 328.5.4 (d) and the Figure 328.5.4D, sketches (1) and (2). In any...
  6. jalvarez

    Branch connections practices

    ASME B31.3, paragraph 304.3.2 establish "that a branch connection has adequate strength to sustain the internal and external pressure which will be applied to it if:" And among the "ifs" the point (b) mentions that the size of the branch must not exceed one-fourth the nominal size of the run...
  7. jalvarez

    ASME B.31.3 doubt

    Yes, I'm referring to a fluid that is M category. Conclusion: all kind of welds for M category must be 20% X-rayed... there is no type to be examined at 5%. Or is there one that I don't see?? I recognize that English is not my laguage, but... I think this is confusing. Thanks to all!
  8. jalvarez

    ASME B.31.3 doubt

    meteng and all, I'm speaking about M341.4(b)(1) Regards
  9. jalvarez

    ASME B.31.3 doubt

    Hi, mates: In the paragraph M341.4 (b)(1) it appears: "The random radiography/ultrasonic examination requirement of para. 341.4.1(b)(1) apply except that at least 20% of circumferential butt and miter welds and of fabricated lap and branch connection welds comparable to those shown in Figs...
  10. jalvarez

    Passwords... and MS bugs...

    Very clear, different levels of security. It looks fine for this kind of shared files. Thanks joerd
  11. jalvarez

    Passwords... and MS bugs...

    Protecting an Excel spreadsheet for writing and selection of some cells, I defined a password. One month later... I forgot the password. Doing a search for lost paswords, it was found SPPBABF as the lost one. Immediatly, I could remembered the first one, SPPFORM. Surprise, the two words works...
  12. jalvarez

    Cold Box HE

    Libero: Brazed HE's use to have mechanical problems at high defferential pressures between their streams. And this problem could be serious during startups, if the plugging of the filters are combined unfavorably. You may have already taken this into account, but I mentioned just in case...
  13. jalvarez

    Assuring sealing with bellows for critical control valves

    Hi mates: Your opinion or experience: For a control valve in a vapor anhidrous hydrogen chloride service, (minus 32°F - 170 psig), is it reasonable to use a metal bellow for sealing the stem to the atmosphere, additional to the conventional sealing system? I think that the efectiveness of a...
  14. jalvarez

    Log plots & maximum for "y"

    Refining Excel results... [pipe] Hi, colleagues Sometimes, making a plot in Excel, we may prefer a logarithmic graphic. This is an option using the Excel wizard for a graphic. But trying to define the maximum value for the "y" variable, Excel increases such muber to the log decade immediatly up...
  15. jalvarez

    Pumps inside a diking area for a low flash point HC

    Hi mates Is there any specific reference (API, NFPA, etc.) defining or recommending about the location of a pump outside of the diking area of a tank, considering that the tank handle a low flash point hydrocarbon? The only reference I've found is an old "recommended practice" that accept the...

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