Free nitrogen inflation! (Only 70% by volume)

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Trindaddy
    Senior Member
    • Jan 2010
    • 339

    Free nitrogen inflation! (Only 70% by volume)

    Please tell me:
    If a system purges using ambient air throughout (which is already 70% nitrogen), why then is it necessary to use bottled nitrogen when testing? Solenoids and valves still open and close and possibly arch/spark occassionally (when atmospheric air is present). Why this precaution when the system exists and operates with 20% O2 all the time anyway?

    Neil
  • Joe Rappa
    Snap-on DSD
    • Aug 2007
    • 2050

    #2
    Good question. It's because if you use shop air to push the smoke into the system, you are adding oxygen. If you add oxygen to a closed container of gas vapors you have an explosion risk.
    Tt's not that you need nitrogen. you just need an absence of oxygen. Any inert gas will work. CO2, Argon, whatever.

    Joe
    "You don't build a reputation on what you're going to do"
    Henry Ford

    Comment

    • Trindaddy
      Senior Member
      • Jan 2010
      • 339

      #3
      Hi Joe,
      Do correct me if i'm wrong, but 20% oxygen is still 20% oxygen no matter how much pressure its under, is it not? (eeld is .5 lbs no?) Inside the evap system cavity is still ambient air. Is it the pressure that makes testing different? Doesnt the system pressure rise and fall on its own during daily driving/operation?

      Comment

      • Steve6911
        Moderator
        • Feb 2007
        • 2168

        #4
        Originally posted by Trindaddy
        Hi Joe,
        Do correct me if i'm wrong, but 20% oxygen is still 20% oxygen no matter how much pressure its under, is it not? (eeld is .5 lbs no?) Inside the evap system cavity is still ambient air. Is it the pressure that makes testing different? Doesnt the system pressure rise and fall on its own during daily driving/operation?
        Every combustible substance (in this case gasoline) has an upper and a lower
        flammability air concentration limit. When you use Nitrogen you are taking away the oxygen, by pushing it out the leaking area. Yes there will be places where the Nitrogen does not displace the oxygen, but why take any chances, Nitrogen is cheap so why take a chance. This topic has been argued many times on many forums, however most vehicle manufactuers state to use Nitrogen. I think I will listen to them.

        Steve

        Comment

        • Trindaddy
          Senior Member
          • Jan 2010
          • 339

          #5
          Why this precaution when the system exists and operates with 20% O2 all the time anyw

          The questions i was asking are very specific and pose real, physical, similarities between testing and everyday driving. I had no intentions of argueing the point of using air or not, that is a personal choice. Rather why is testing any different than normal use. Why dont evap systems explode during the day to day? My question is not "why should i use nitrogen?". Instead, what is different about testing one with air and driving one with air? I personally use my tester for all sorts of system tests and grew tired of running out of nitro and running to get more when it never really seemed necessary.
          Some things are obviously "cover your ***" statements, some aren't as obvious and provoke reasoning. Never hurts to ask.
          Last edited by Trindaddy; 03-13-2011, 08:55 PM.

          Comment

          • Steve6911
            Moderator
            • Feb 2007
            • 2168

            #6
            This story starts out simply enough. I first used a smoke machine in the spring of 1995 and loved it, so I included it in a feature story on leak detection in our June 1995 issue. I also began recommending the technique to anyone and everyone who’d listen. Those who took my advice always responded, …


            The Evap portion of this article is toward the bottom. Maybe it can explain it a bit better then I did. Here is a copy and paste of part of it.
            Some guys argue that the risk of an evap-related fire or explosion is minuscule, but it takes only one accident to ruin your day. I'll leave the debate at this: Forewarned is forearmed.



            Steve
            Last edited by Steve6911; 03-07-2011, 09:36 AM.

            Comment

            • Trindaddy
              Senior Member
              • Jan 2010
              • 339

              #7
              No Steve, he did just as well as you. Gave the blanket statement but didnt give any reason why this oxygen that is present is any different than any other time. I do not expect anyone in his position to say anything other than what he did. I find the "blind faith" answer safe, but silly.

              Comment

              • Glenn Richardson
                Junior Member
                • Feb 2011
                • 8

                #8
                Originally posted by Trindaddy
                Please tell me:
                If a system purges using ambient air throughout (which is already 70% nitrogen), why then is it necessary to use bottled nitrogen when testing? Solenoids and valves still open and close and possibly arch/spark occassionally (when atmospheric air is present). Why this precaution when the system exists and operates with 20% O2 all the time anyway?

                Neil
                When purging it only purges the canister and lines. (Very very little from the tank.) The issue of using nitrogen I beleive is mis-understood. If you use Nitrogen or shop air you are pushing HC's out of the fuel system and out into the work bay. The difference is, if there is a point of ignition in the work bay the flame could work it's way back into the fuel tank! If there is no O2 in the tank how can it? The 70% nitrogen that you wrote about is the same that goes into the intake to make the engine run --SO -- to stop the flame from running back into the tank you would need a higher % of nitrogen - say 98% or better. NO O2 no flame. High % of Nitrogen NO flame. You are right 70% nitrogen you can still have enough O2 to make fire! I hope this helps

                Comment

                • Trindaddy
                  Senior Member
                  • Jan 2010
                  • 339

                  #9
                  Nicely done Glen! That makes sense and causes me to re-consider my position. Great 1st post. What else ya got?

                  Comment

                  • Glenn Richardson
                    Junior Member
                    • Feb 2011
                    • 8

                    #10
                    Originally posted by Trindaddy
                    No Steve, he did just as well as you. Gave the blanket statement but didnt give any reason why this oxygen that is present is any different than any other time. I do not expect anyone in his position to say anything other than what he did. I find the "blind faith" answer safe, but silly.
                    I'm sorry, I'm new on the this forum and didn't want to offend anyone or over step my boundries. I'm sorry if I was not clear . I just wanted to help. The question was
                    "If a system purges using ambient air throughout"
                    lets start there -- Are you thinking the fuel tank is being purged like the canister? The answer is NO it isn't! The system is NOT being purged through out. Is there O2 in the canister when purging YES! BUT it doesn't go through the tank! It takes 1.5 liters by volume of O2 (with 70% nitrogen) in a 16 gal tank to start to become an issue. MOST smoke machines put out 10 plus liters a minute.

                    Next
                    "Solenoids and valves still open and close and possibly arch/spark occassionally "
                    Is the electrical side of the solenoid exposed to the fume side? None that I have seen. I'm open to look at or buy any solenoid that you know of that the electrical side of the solenoid IS exposed to the fumes. All those that I can remember are NOT exposed. I have not seen them all.

                    Next
                    " Why this precaution when the system exists and operates with 20% O2 all the time anyway?"
                    I thought I was clear and I was not. Like I said using SHOP AIR or NITROGEN the problem of pushing HC's out into the work bay is the same --100% the same. THE difference is IF there is a point of ignition out side the EVAP system (in the work bay) can it wick its way back into the tank -- My answer is YES if you are using SHOP AIR with 70% Nitroben as you put it. The chance decreases as the amount of O2 decreases. It also decreases, with a higher % of Nitrogen say 98% instead of 70%. Try not to get hung up on the Nitrogen as much as the O2 -- It is the O2 that is needed to support combustion.

                    Comment

                    • Glenn Richardson
                      Junior Member
                      • Feb 2011
                      • 8

                      #11
                      Just EVAP stuff -- That is petty much all I do anymore. 35 years into this industry and 20 of those years fixing cars and the last 15 EVAP systems.
                      But I like it a lot. It is fun and alway changing. I hope I can help.

                      Comment

                      • Steve6911
                        Moderator
                        • Feb 2007
                        • 2168

                        #12
                        Originally posted by Glenn Richardson
                        I'm sorry, I'm new on the this forum and didn't want to offend anyone or over step my boundries. I'm sorry if I was not clear . I just wanted to help.
                        Glenn
                        By no means did you overstep your boundries, and there is no need to be sorry! You gave a great (and clear) answer and THANK YOU for the help! And once again I am glad to have you here on the forums!

                        For those you you who do not know Glenn, he is the reason my shop bought the Snap-on evap smoke machine. Besides the classes he taught on evap systems he ran the tech line for S.O.'s smoke machine. He knows more about evap systems then anyone I have ever met (Sorry Joe, but your a close second ). He was always there when I needed him and I am sure he will be a GREAT asset to the Evap Forum. THANKS AGAIN Glenn

                        Steve

                        Comment

                        • Joe Rappa
                          Snap-on DSD
                          • Aug 2007
                          • 2050

                          #13
                          Originally posted by Steve6911
                          Glenn
                          By no means did you overstep your boundries, and there is no need to be sorry! You gave a great (and clear) answer and THANK YOU for the help! And once again I am glad to have you here on the forums!

                          For those you you who do not know Glenn, he is the reason my shop bought the Snap-on evap smoke machine. Besides the classes he taught on evap systems he ran the tech line for S.O.'s smoke machine. He knows more about evap systems then anyone I have ever met (Sorry Joe, but your a close second ). He was always there when I needed him and I am sure he will be a GREAT asset to the Evap Forum. THANKS AGAIN Glenn

                          Steve
                          Wow! What a great bunch of activity on this thread! And it was productive too!
                          Glenn, thanks for helping out. I am glad you signed up here.
                          Steve, no reason to apologize. Glenn lives, eats, sleeps and breathes EVAP stuff. I'll never know what that guy does, and most of what I know about EVAP came from his training.

                          Joe
                          "You don't build a reputation on what you're going to do"
                          Henry Ford

                          Comment

                          • Trindaddy
                            Senior Member
                            • Jan 2010
                            • 339

                            #14
                            I too have had some very good discussions with an older gentleman at the EELD tech support line. I have also stated before that perhaps the strongest part of this machine was the support that came with it. I dont know if it was you Glenn, and i'm sure if it was, i was one of many. We discussed how to easily test the Jeep system i was working on and how i had rigged up an AC vacuum pump to help accomplish this. I spoke to you a few times within a few months regarding the testing of these sytems and you were kind enough to allow me to view your "stuff" online w/you. You also assisted me in getting a new S.O. unit when mine kept having "low voltage" issues.
                            I have used the EELD much since we spoke, and have learned a lot as i did today. Thank you Glenn for the concise explanation and thank you S.O., people will always judge you (S.O.) by the company you keep (that includes you Steve and Joe)!

                            PS. Steve, i still need help with the SJB mustang on the J2534 forum if you got time....

                            Comment

                            • Glenn Richardson
                              Junior Member
                              • Feb 2011
                              • 8

                              #15
                              Originally posted by Trindaddy
                              I too have had some very good discussions with an older gentleman at the EELD tech support line. I have also stated before that perhaps the strongest part of this machine was the support that came with it. I dont know if it was you Glenn, and i'm sure if it was, i was one of many. We discussed how to easily test the Jeep system i was working on and how i had rigged up an AC vacuum pump to help accomplish this. I spoke to you a few times within a few months regarding the testing of these sytems and you were kind enough to allow me to view your "stuff" online w/you. You also assisted me in getting a new S.O. unit when mine kept having "low voltage" issues.
                              I have used the EELD much since we spoke, and have learned a lot as i did today. Thank you Glenn for the concise explanation and thank you S.O., people will always judge you (S.O.) by the company you keep (that includes you Steve and Joe)!

                              PS. Steve, i still need help with the SJB mustang on the J2534 forum if you got time....
                              Thank you all for the nice replies. Joe asked me to come on board here. I'm on the road a lot and may not be able to get to all posts. If you have a issue (EVAP problem) and I'm not on line -- Please use Joe to contact me and I will do whatever I can to help. (I hope that is OK Joe)(pay back) I don't have all the answers but what I do have is access to a lot of people at the OEM's. Trust me everyone, if any of you did nothing but head light switches for 15 years you would know as much about head light switches as I do EVAP. --

                              Comment

                              Working...