Forum Technical Discussions Re: Helium-Ammonia mixture for leak test Posted by: Faran Hussain , E-mail: Address, on May 13, 2008 at 12:11 : In Reply to: Re: Helium-Ammonia mixture for leak test posted by : alberto , E-mail: Address, on May 12, 2008 at 18:50 : Thanks for your reply. We are experiencing a very minute leakage in our Urea Stripper (carbamate on Tube side & steam on shell side). Here are the details of the two leakage tests we can perform separately. Ammonia Leakage Test: Method used: Pressure Method Tracer Gas Used: Ammonia Detection Method: Ammonia Sensitive paper Total time required for the test is about 12 hours. A mixture of Nitrogen & 15% by volume of Ammonia is used to pressurize the shell side. A soaking time of approx 8 hours is required. Nitrogen is used to increase the pressure & thus increasing the sensitivity. Helium Leak Test Method : Sniffer Method Tracer Gas: Helium Detection Method: Mass spectrometry Total time required for the test is about 8-10 hours. A mixture of Helium & Nitrogen is used to pressurize the shell. The soaking time is 1 hour. Nitrogen is used to increase the pressure & thus increasing the sensitivity. Now to save time, why not use a mixture of helium & ammonia to pressurize the shell side. This way after 1 hour of Helium soaking we would be able to start performing Helium Leak Test and by the time we would complete our helium leak test hopefully soaking time of ammonia (i.e 8 hours) would be over and we would apply ammonia sensitive paper on both tube sheets. As helium test is not recommended in moist environments. The molecule of Ammonia & that of water are similar in terms of hydrogen bonding. So one of our apprehension is that would ammonia gas would behave like moisture and adversely effect the sensitivity of helium leak test. More details can also be provided. we would definetly love to have your assistance. Helium Leak tester being used by us is MKS sniffer method using mass spectropetry. Follow Ups: Post a Followup: Name: E-Mail: Subject: Comments: ----------- Start Original Message ----------- : Thanks for your reply. We are experiencing a very minute leakage in our Urea Stripper : (carbamate on Tube side & steam on shell side). Here are the details of the two leakage tests we can perform separately. : Ammonia Leakage Test: : Method used: Pressure Method : Tracer Gas Used: Ammonia : Detection Method: Ammonia Sensitive paper : Total time required for the test is about 12 hours. : A mixture of Nitrogen & 15% by volume of Ammonia is used to pressurize the shell side. A soaking time of approx 8 hours is required. Nitrogen is used to increase the pressure & thus increasing the sensitivity. : Helium Leak Test : Method : Sniffer Method : Tracer Gas: Helium : Detection Method: Mass spectrometry : Total time required for the test is about 8-10 hours. : A mixture of Helium & Nitrogen is used to pressurize the shell. The soaking time is 1 hour. Nitrogen is used to increase the pressure & thus increasing the sensitivity. : Now to save time, why not use a mixture of helium & ammonia to pressurize the shell side. This way after 1 hour of Helium soaking we would be able to start performing Helium Leak Test and by the time we would complete our helium leak test hopefully soaking time of ammonia (i.e 8 hours) would be over and we would apply ammonia sensitive paper on both tube sheets. : As helium test is not recommended in moist environments. The molecule of Ammonia & that of water are similar in terms of hydrogen bonding. So one of our apprehension is that would ammonia gas would behave like moisture and adversely effect the sensitivity of helium leak test. : More details can also be provided. we would definetly love to have your assistance. Helium Leak tester being used by us is MKS sniffer method using mass spectropetry. ------------ End Original Message ------------ Optional Link URL: Example: "http://www....html". Alternative write "http://www.ndt.net/wshop/attach/filename.htm" if you transfered a filename.htm via FTP Page Title: is important! Optional Image URL: http://www....gif Attention! Please click the button only once. This may take a moment to process Forum Technical Discussions Help