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  • Users: unsy
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  1. unsy

    Butterfly Valve Material

    You can use cast iron for the design of a pressure vessel such as a Butterfly valve and the sizes and pressure you mentioned and this has been done by many valve manufactures, however it is not possible to generalise. You must look at more than just the pressure loading, piping end loads and...
  2. unsy

    Valve seat and disc hardfacing

    osuamp I would guess the problem you have here is not due to materials but the valve design itself. With the advent of changing plant operating philosophies, valves are now heated up and cooled down far more frequently and quickly than previously. This leads to a significant thermal gradient...
  3. unsy

    What is "valve rating" and "Valve class" ?what differencre

    The rating of a valve if you take B16-34 is the maxiumum pressure (psig) at a specified temperature (deg F) for a specified material (ASTM/ASME). A Class covers all the ratings for the particular material within the specified temperature range. For example Class 150 for WCB would cover all the...
  4. unsy

    End Loads

    The easiest way to do this is to compare the section modulus of the pipe against the valve end and then take ino cosideration the applicable ratio of allowable stress values for the pipe and valve materials. (don't forget casting factors is volumetric testing is not carried out)
  5. unsy

    Equivalent valve standard

    The copy I have is Pr-En however I assumed that when it is released it will become BS-EN .... With regard to the PED the hazard analysis is something that is covered by the directive only and is handled between individual manufacturers and their notified body. I don’t know of any ASME standard...
  6. unsy

    Valve design for shell integrity

    If you are using B16-5 or B16-34 it is not helpful to think in terms of over pressure. The maximum pressure a vessel or flange rated to these standards can be used for is based on the relevant rating table for the material. You must not forget temperature. As peaseman said B16-34 is...
  7. unsy

    Equivalent valve standard

    The new standard to be released will be BS EN 12516. It will be a 3 part standard, you need part 1 (Tabulation method). Not sure if it is past pr status yet. It is basically a direct copy of B16-34 so don't expect anything exciting. With the hazard analysis what are you looking for, are you...
  8. unsy

    gate-ball valves

    Ball or Plug valves would be your best option for this kind of duty, one thing to look out for is the cost of the operator (can be more than the valve), floating type ball valves normally need pretty big operators.
  9. unsy

    earthquake safety shutoff valve

    There are already many valve companys that offer product to satisfy this need, it is already a very cost driven market. Have a look at the BVAMA or VMA web sites.

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