All Member Open Forum

 View Only
  • 1.  Reliability Concern

    Posted 08-04-2020 01:26 PM
    We recently replaced warm water vaporizer at the plant with a replacement in kind HX. Since doing so, it has begun to make a gurgling / cavitation noise. We cut back on the discharge valve and it seemed to help but it still comes and goes. I want to make sure the cavitation does not damage the tubes inside.

    Has anyone seen anything like this before and do you have any suggestions to remedy?
    Thanks

    ---------------------------------
    Eric Mensah-Onumah

    Airgas USA, LLC
    Houston TX
    ---------------------------------


  • 2.  RE: Reliability Concern

    Posted 08-05-2020 11:10 AM
    Never seen that before but something is either wrong with your process or your HX.  You'll have to work thru all the details in some sort of RCFA process to drill into potential issues.  Here are a few random possibilities.

    • HX is not the exact same as one removed.  See this on many replacement projects even if it is ordered correctly.  Need to make sure it is the same.
    • Something inside HX or lines - blank left in, screen or rag from installation that was not removed or got overlooked.  Cutting back the flow you mention seems to solve the problem which is typical for a high flow cavitation issue.
    • Check the process for proper system startup and operation.  Maybe a valve got left open or shut causing some process balance issues.
    • Verify temperature and pressure conditions of your process.  Verify feed pump operation for any clues to the root cause.
    • At startup, did all the air get vented or purged from the HX or system?

    Good luck on your investigation.

    ------------------------------
    Randy Riddell, CMRP, PSAP, CLS
    Reliability Manager
    Essity
    Cherokee AL
    ------------------------------



  • 3.  RE: Reliability Concern

    Posted 08-05-2020 11:20 AM
    Randy
    Thanks so much for the thoughts. Will start with these possibilities. Will you posted

    ---------------------------------
    Eric Mensah-Onumah

    Airgas USA, LLC
    Houston TX
    ---------------------------------





  • 4.  RE: Reliability Concern

    Posted 08-06-2020 12:47 PM
    Hello,
    I agree with the follow-up comments that RCA (or RCFA) is much needed to drill down to root cause. This is a common issue where "replacement is kind" is not true replacement and sometimes the start-up/shut down process to do replacement can be a concern as well . For example system lines may need to be full of fluid or (air released) as an example. Please keep us posted with this interesting challenge, we all can learn from it.
    Thanks,
    Akshay.

    ------------------------------
    Akshay Kulkarni
    Staff Engineer - Systems and Reliability
    Roche Tissue Diagnostics
    Tucson, AZ
    ------------------------------



  • 5.  RE: Reliability Concern

    Posted 08-06-2020 09:24 PM
    Sure, l will definitely keep you posted on any findings

    ---------------------------------
    Eric Mensah-Onumah
    Reliability Engineer

    Houston TX
    ---------------------------------