×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Ice in my Halt chamber

Ice in my Halt chamber

Ice in my Halt chamber

(OP)
Hi all,
We have a QualMark Halt & Hass chamber here at my work.  I can't seem to figure out how all the moisture is getting into it.  When we take it down below zero C it ices up bad. We don't have the nitrogen purge hooked up but the other guy figures that after a while the LN2 used to cool the chamber should have driven out the moisture anyway. The website wasn't very much help.  Does anybody know if the chamber is sealed on these usually and the LN2 goes through a heat exchanger or is it shot directly into the chamber?  

RE: Ice in my Halt chamber

When you drive the temperature down, the internal air pressure also goes down, which causes external air to enter.  Are all your air sources adequately dried?

TTFN

FAQ731-376: Eng-Tips.com Forum Policies

RE: Ice in my Halt chamber

Many of these machines have nitrogen to energize the door seals;  do you have that hooked up, if it is so equipped?  

RE: Ice in my Halt chamber

(OP)
The first thing i suspected was the compressor air entering the chamber to run the drivers on the vibe table.  I checked and it has a working water remover.  The low pressure thing would cause air to enter anywhere it could though and we've been relatively humid here lately.  We are not currently using nitrogen for anything but cooling but the chamber is able to do more, like nitrogen purging.  Maybe we need to start there.  

RE: Ice in my Halt chamber

ou are definately going to have to keep a positive pressure "purge" of completely dry gas (note I didn't say air) as the temp comes down.

Also I doubt your compressor air is anywhere near as dry as you suppose. (is the dryer a dessicant type? Hows the media?)

RE: Ice in my Halt chamber

(OP)
I'm trying to convince them to connect the nitrogen gas purge system since our tank and chamber are set up for it.  This morning we put new foam in all the ports and it seemed to help quite a bit but we still have a little snow and fog.  The drier is not deccicant type. Its the type with a little glass jar.  Its not full but does have some fluid in it.  I think the purge system is the only way to really get that last little bit out.  

RE: Ice in my Halt chamber

Quote:

A "little glass jar" is not a dryer, it's to trap LIQUIDs, leaving plenty of room for vapor.

Agreed.  Vent the shaker table air outside the chamber.

-b

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources