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Name/source for mounting hardware

Discussion in 'Electronic Components' started by David Lesher, Apr 29, 2013.

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  1. David Lesher

    David Lesher Guest

    I'm seeking those clips that hold TO-92 cases. They look sorta
    like the number 9, with the TO-92 going in the donut hole, and
    the tail having a hole for a mounting screw. They hold the
    device parallel to the mounting surface.

    But I am having no luck finding the right term to describe such
    to Mr. Digikey or Ms Mouser.....Suggestions?

    I'm open to alternatives; our task is to fasten a temp sensor
    to a 0.25" OD copper line to sense the fluid temp. within...
    I planned to solder the clips to the line...
  2. haven't seen those in a while.
    It's not quite what you want, but might work, and is probably the only
    off the shelf item like this anybody even makes:

    here's how it mounts. Cut the top tab and legs off and just solder it to
    the tube? It's going to look pretty homemade.
    Tough one as you've got the worst possible shapes to join.
  3. JB

    JB Guest

    Keystone do some interesting stamped metal parts.

  4. Rick

    Rick Guest

    If you insulate the sensor AND the pipe it will work. If the temperature is
    not too high you can use something like "Great Stuff".
  5. A more intrusive way is to adapt the 0.25" tube to a larger (maybe
    3/8") tube with a T-fitting so the fluid makes a 90° turn, and insert
    a sealed probe deep into the larger tubing (say 10 diameters of the
    probe OD plus the sensitive end length). The hard right turn also
    causes turbulence if you have enough flow, and prevents laminar flow
    which will screw up your readings. Read about Reynolds numbers and
    such if you're interested- it can be important. A 1/8" OD probe would
    be better than something a TO-92 will fit into.

    More Mickey Mouse (tm) would be to put a dollop of heatsink compount
    on the TO-92 (with attached and electrically insulated leads,
    obviously), wrap wide adhesive copper tape around the two, and finish
    with some adhesive-lined shrink tubing and outer (thermal) insulation.
  6. Guest

  7. And sandwich that (short) section of copper pipe between sections of
    plastic pipe.
  8. Joerg

    Joerg Guest

    I believe they are called "transistor clips". Talk to these guys:

    Careful with beryllium-copper, personally I would not use those.
  9. How about beryllium-copper with cadmium plating?
  10. Thats called a 'loop strap'

    You can try Keystone, RAF too.

  11. Joerg

    Joerg Guest

    Probably ok as long as nobody saws or scrapes. But then one fine day
    somebody does ...
  12. I'm imagining the copper tube goes through bulkhead fittings, into
    tanks, bolted into pumps, held with hangers mounted to metal etc. that
    could significantly change the temperature of the tubing relative to
    the liquid flowing inside.

    If your model is an effectively infinite length of thermally isolated
    copper tube with liquid of the same temperature throughout then there
    is no need of the insulation I suggested.
  13. Jamie

    Jamie Guest

    What you need then, is to use those circuit board fuse holders..

    you get the size for the 1/4" fuses and you can snap the sensor in the
    holder. You can solder this to a copper piece of course.

    The URL links are far to long but go to mouser and look for
    "Fuse clips" you put two of these on your pipe so that the wires
    will hang out on one end and the tip of your sensor will sit in the
    other end.

  14. You forgot the beryllia insulating (electrical) wafer that's ground into a
    special shape.
  15. David Lesher

    David Lesher Guest

    Exactly our plan. We will not create leak opportunities,
    there are enough already. If we wrap the tube+sensor
    with insulation, it will be fast enough for our needs.
  16. David Lesher

    David Lesher Guest

    The fuse clips idea is a good one; we'll look at that.

    The sensor will be on a 1-2" long segment of tubing solely
    for temperature sensing. The plastic tubing isolates it.
    It will be wrapped with insulation against wind.

    Yes, it won't be the fastest response, but in this application,
    BFD; it will be fine.

    We are NOT going to play with thermistors, thermocouples and
    other instruments of aggravation and annoyance; I'm in recovery
    from same. The Device Gods let us buy I2C and 1-Wire sensors,
    and the output is bits.... nice friendly bits.

    The 1-Wire vs. I2C decison is more nuanced; I2C has a TO-220
    package but the tab is not electrically isolated. 1-Wire has
    TO-92's that we can bury in a hole on the busbars. The CPU has
    I2C support directly; but there's a I2C to 1-Wire chip that
    sounds interesting, the DS2483. Maxim wants $85 for their simple
    eval kit - DS2483K# so we'd make our own from a 2483.
  17. David Lesher

    David Lesher Guest

    Looked but don't find a hit on such in their catalog.
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