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what is this?

Maybe it is an inline trap or an inline check valve. Would it make sense if these were traps?


  • rob brown
    rob brown Member Posts: 69

    can anybody tell me what these are? my guess is a left-right coupling in place of a regular union. found 3 of them on one pipe steam job. rob
    EBEBRATT-Ed Member Posts: 10,218

    If theres no union in the pipe then thats what it is a left-right coupling. Don't see a lot of them but they were pretty common.

  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928

    Some sort of "repair coupling"?
  • Jerry_15
    Jerry_15 Member Posts: 379

    It looks like it comes apart. Would I try to take it apart? Noooo. Somebodies cool invention that didn't quite catch on, wouldn't pass code in a wall anyhow these days, and that might have been what spelled their doom. If you have to cut one out, I'd love to know the answer. Be very surprised if it's a reverse coupling..
  • Jerry_15
    Jerry_15 Member Posts: 379

    On water maybe, (it does look like a spring check) but on steam? Someone will know instantly, might have been a local factory that went broke before they got big.
  • Steamhead (in transit)
    Steamhead (in transit) Member Posts: 6,688
    It's an old-time gasketed union

    the larger part of the coupling had standard pipe thread and the smaller had a running thread. The short nipple going into the smaller part also had a running thread and was part of the unit. You screwed everything into place including some sort of gasket between the two coupling pieces. I'm not sure what the gasket was made of or if the running threads were left-hand.

    We still find these in old Baltimore piping too.

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  • rob brown
    rob brown Member Posts: 69

    i knew you guys would have the answer. looking at the piping,it had to be some kind of union unless somebody "turned the world" to tighten it up. rob
  • mtfallsmikey
    mtfallsmikey Member Posts: 765
    Sort of looks like

    A different type of Dresser coupling. We used these extensively back in the day to repair black / galv. pipe.
    But, I've seen only a few of these left / right couplings.
  • JK_4
    JK_4 Member Posts: 35

    I have heard many of the posters here indicate that left and right nipples and couplings are "rare" or "not used". I felt in was time to add my 2cents. Left and right nipples and couplings are very common in NYC. They can be purchased in every supply house. They are required by code for many applications. And they are part of the NYC master plumbers lic. test in the practial part. I use them regularly and stock them on my trucks. If any one is interested in them I would be more then willing to help you get started with using them as they are almost as common as unions and a great way to make certain repairs.

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  • powerhead
    powerhead Member Posts: 26

    It does look like a Left/Right coupling in that it has 4 ribs around it. Thats what I was taught, regular copupling, 2 ribs, L/R coupling, 4 ribs, usually with a 4 in nipple.

    It also looks like it is in two pieces as the ribs are not lining up.


    A Left/Right Right/Left something-a-ma bob?
This discussion has been closed.