Newbie require suggestion for solution

Discussion in 'The Projects Forum' started by qingwei, Aug 5, 2013.

  1. qingwei

    Thread Starter New Member

    Jul 29, 2013
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    Hi all ,
    There is an attachment below that I have currently facing a problem with. My project require me to shield the wires using copper pipe. However , my team and I are currently facing this problem. The joined female and male part of the component is an obstacle because the diameter of it is significantly larger than the dimension of the pipe needed to coat the wire.
    Do you guys have any suggestion in which that can solve this problem?
    thanks in advance
    --QingWei--
     
  2. LDC3

    Active Member

    Apr 27, 2013
    920
    160
    Could you use a larger copper pipe?

    Could you cover the lines with the pipe you have and use a larger pipe (or other metal material) to cover the connection?

    Are there any other restrictions we need to know about?
     
  3. WBahn

    Moderator

    Mar 31, 2012
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    You haven't given any indication of what the problem is. You've stated that the diameter of the pipe needed to accommodate the connectors is significantly larger than would be needed to shield just the wires. That's merely a statement of fact, not a statement of a problem. Try completely this sentence:

    This is a problem because ... and in order for a solution to be acceptable, it must ....

    Why is there a connector at all? Does it need to be accessible?
     
  4. qingwei

    Thread Starter New Member

    Jul 29, 2013
    10
    0
    Hi all ,
    Sorry to include some specific details. The connector is actually the vga to dp cable. Because it is outside shielded enclosure, we have to shield it to prevent electromagnetic interference.

    The diameter of the joined female n male part is 30mm. Our objective is to ensure that the pipe secure(making sure it wont have a wire range of movement) the wire and protect the wire. The disadvantage of using a large copper pipe would not secure the wire and risk electromagnetic interference entering it. We also thought of joining 2 copper pipes together but risk emf entering.

    For your information, after adding the pipe , a 90 degree bend down would be required because the monitor would be place on the floor for emc testing.

    We could not use other materials because except silver, copper has the best conductivity in metal(best for shielding).

    This is a problem because we have to 1. ensure that the wire and connector is entirely shielded without any EMI entering, 2.the diameter of the pipe cannot be too big because the wire would not be secured and 3.we could not use anything adhesive as it is an insulator and reduce shielding effectiveness. In order for the solution to be acceptable, the mating part must still be accessible .
    I would require your advices and Sorry for the lack of details. Thanks in advance

    --QingWei--
     
  5. WBahn

    Moderator

    Mar 31, 2012
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    One solution would be to put ultrahigh vacuum flanges at the joint where the connector is. Solder/braze these to the copper tubes. These types of flanges typically use a copper gasket to make the seal. I think these are called Conflat flanges, though IIRC the generic term is CF flange because Conflat is a trademark of either Kurt J. Lesker Company or Varian, I forget which. It's been 25 years since I did anything with this stuff.
     
  6. wayneh

    Expert

    Sep 9, 2010
    12,090
    3,027
    A somewhat conventional solution is conduit pipe and junction boxes. Large variety of options.

    [​IMG]

    [​IMG]

    [​IMG]
     
  7. strantor

    AAC Fanatic!

    Oct 3, 2010
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    I think the braided shield of a shielded cable would be much more effective than a copper pipe. And much cheaper. Why not just use shielded cables?
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Follow on from this post?
    http://forum.allaboutcircuits.com/showthread.php?t=87758
    If you need to retain the integrity of the copper I would think you need to manufacture some kind of copper trough fitting, this could be done with standard fitting and large dia pipe and end flanges, either purchased or made up..
    There are ebay sellers of copper pipe in short pieces up to 6" in dia!.
    Max.
     
  9. WBahn

    Moderator

    Mar 31, 2012
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    It sounds like they are doing some kind of testing in which it is critical to mitigate virtually all EMI from getting at the cables. In that case, most junction boxes won't work because they have too many gaps and slits. I was amazed when I found out how much EMI a slit for a ribbon cable or just the slit when an enclosure lid is closed allows in/out. The steps taken to mitigate the last little bits of EMI can be pretty Herculean. But a careful examination of junction boxes might reveal some that can form the basis of a workable solution.
     
  10. wayneh

    Expert

    Sep 9, 2010
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    The screw seal type (3rd example above) is widely seen in industrial instrumentation. EMI is one concern in that application, but so is washability. No idea how effective it is against EMI, but I guess my point is to exhaust commercially available solutions before going for Rube Goldberg.
     
  11. WBahn

    Moderator

    Mar 31, 2012
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    I agree. It might also be worth a call to an EMI testing facility and see what their recommendations are for adequate shielding.
     
  12. qingwei

    Thread Starter New Member

    Jul 29, 2013
    10
    0
    Hi all ,
    First of all , sorry for my lack of illustration and clarity of the question.

    I did suggest all your recommendation to my supervisor. Then he posted another question(refer to the attached folder for better reference.
    Question: The problem is how do you insert a copper pipe that have a large surface on both side , but a small surface in the middle.
    After which , he suggested this solution.
    Suggested Solution:You all go find one metallic material(copper) and manufacture a part out(refer to attached folder as rough reference). I just use the green highlighter as illustration. However , since we have to manufacture it ourself , it would definitely include screws . I came across this book(i uploaded a photo of it) and it seems like there are still holes in between despite how tight we manufacture. And also , it will not be easy to attach the part onto the connector without damaging the connector.

    FYI , a 90 degree bend is required. There is an attachment on a picture of the connector. It is the front connector. The back part of the connector is broken and currently in soldering process. The back part is exposed to the environment as we have to cut deeper into the strip to solder the wire back into place.

    Quote from

    Quote from strantor "I think the braided shield of a shielded cable would be much more effective than a copper pipe. And much cheaper. Why not just use shielded cables? " The connector at the front is not shielded(we purchased it). The connector that is at the back is shielded(inhouse-DIY by previous project group). In short , we just shield the entire cable to prevent EMI .

    Quote from MaxHeadRoom " Follow on from this post?
    http://forum.allaboutcircuits.com/sh...ad.php?t=87758"
    Yes indeed the website helped. Later on , he posted me a problem on how to insert the copper pipe to shield the wire from the "big" ends and the wire in the middle.

    Quote from wayneh:"No idea how effective it is against EMI". Indeed I have also no idea whether it is against EMI. But it seems that there is holes that does not act like filter. My guess is that , it is meant to direct the wire. Correct me if I'm wrong.

    Sorry all for my brief explanation on the previous post "1. ensure that the wire and connector is entirely shielded without any EMI entering, 2.the diameter of the pipe cannot be too big because the wire would not be secured "
    Thank you for your advices. I hope to receive good news from you guys soon.
    --QingWei--
     
    Last edited: Aug 5, 2013
  13. wayneh

    Expert

    Sep 9, 2010
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    Not in the industrial versions, which are meant to resist pressure washing and other environmental issues. One area in our plant even had vapor explosion-proof enclosures.

    Yes, the home versions are not sealed and are mostly for mechanical protection, maybe also for fire prevention.
     
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