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Thread: Internal support of steel schedule 80 pipe

  1. #1
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    Internal support of steel schedule 80 pipe

    I currently have a situation where I use 1" schedule 80 steel pipe to feed two .203 ports and maintain 7k psi water pressure. due to the application external support is not possible. I am trying to minimize sag. I have considered using an X or Y configuration essentially creating a 21' steel X and placing it thru the pipe. and spot welding it in place thru drilled ports. what I would like to know is in order to keep sufficient volume to feed the two .203 ports and maintain the 7k psi what thickness steel to use and what diameter pipe I may have to use to in order to maintain this volume and pressure. if more information is needed I will try to supply as much as I can. I am also dealing with 30 to 50 mph of turbulence and 1000 to 2000 degree temperatures. any help would be appreciated. let me know if I have posted this in the wrong forum

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    Lead Engineer Cake of Doom's Avatar
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    If you could let us know what the proposed application is and perhaps attach a sketch of your idea, it might make it a bit clearer for us.

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    Administrator Kelly Bramble's Avatar
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    Quote Originally Posted by phantomofky View Post
    I currently have a situation where I use 1" schedule 80 steel pipe to feed two .203 ports due to the application external support is not possible. I am trying to minimize sag.
    Quote Originally Posted by phantomofky View Post
    21' steel X and placing it thru the pipe. and spot welding it in place thru drilled ports.
    Quote Originally Posted by phantomofky View Post
    What diameter pipe I may have to use to in order to maintain this volume and pressure.
    Cake of Doom,

    I think the op wants to minimize the sag of the pipe by inserting material into the pipe and spot welding via access holes drilled along the length of the pipe all while maintaining the desired flow and pressure capability of the pipe...


    My thoughts;

    1. Modifying the pipe to reduce sag is interesting and inserting a structural piece will change the flow capacity of the pipe.
    2. Also, the modifications sounds really expensive to me...
    3. Estimating the flow capacity at pressure can be done here ---> http://www.engineersedge.com/fluid_f...alculation.htm and http://www.engineersedge.com/fluid_f...alculation.htm
    4. Can the op simply use a schedule 160 or drawn pipe with custom wall thickness?
    Last edited by Kelly Bramble; 08-13-2013 at 07:26 AM.

  4. #4
    Lead Engineer Cake of Doom's Avatar
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    Quote Originally Posted by Kelly Bramble
    I think the op wants to minimize the sag of the pipe by inserting material into the pipe and spot welding via access holes drilled along the length of the pipe all while maintaining the desired flow and pressure capability of the pipe...
    This is the bit that got asking what the application was because without any particular reason, this sounded a bit like an over complication. Perhaps I should have specified that I meant the application of the pipe and not the stiffeners.

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    Administrator Kelly Bramble's Avatar
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    Quote Originally Posted by Cake of Doom View Post
    This is the bit that got asking what the application was because without any particular reason, this sounded a bit like an over complication. Perhaps I should have specified that I meant the application of the pipe and not the stiffeners.
    I don't think I worded my response you very well, my apologizes.

    Yes, running 7k psi water pressure through an unsupported length of pipe needs to be conceptually examined.

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    Administrator Kelly Bramble's Avatar
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    I just cleaned this thread up - the automated moderation function did not like my post and hid your posts as well Cake of Doom (COD). I deleted two redundant posts too.

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    Lead Engineer Cake of Doom's Avatar
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    Quote Originally Posted by Kelly Bramble View Post
    I just cleaned this thread up - the automated moderation function did not like my post and hid your posts as well Cake of Doom (COD). I deleted two redundant posts too.
    The board kept giving me some strange messages so, I did the only thing an internet wizard like me can do: keep hitting the button till something happens.

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    Administrator Kelly Bramble's Avatar
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    Quote Originally Posted by Cake of Doom View Post
    The board kept giving me some strange messages so, I did the only thing an internet wizard like me can do: keep hitting the button till something happens.
    That's funny. EE had a spam attack last year by automated and manual methods. I engaged a third party automated spam management function that almost completely stopped the robo-spam but the application is imperfect and moderates good folks.

    RWOLFJR and jboggs get pushed into the moderation que often and I still can't figure out why...

  9. #9
    Lead Engineer Cake of Doom's Avatar
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    I was getting a "Are you sure you want to leave this page?" message whenever I hit quick reply; If I hit ''leave'' it would take me to a post preview page and tell me I needed to wait 30 seconds before trying again. Very strange.

    Sounds like RoboMod is a little too effecient... Is it just you on your own to moderate the whole board?

  10. #10
    Administrator Kelly Bramble's Avatar
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    Quote Originally Posted by Cake of Doom View Post
    Is it just you on your own to moderate the whole board?
    PinkertonD was helping at that time. When the we where in the spam-a-thon era we where getting 100+ spam posts daily...

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    the application is for industrial cleaning in a boiler. use a semi automated machine to deliver 7k psi thru the schedule 80 pipe. which has .203 tips in a tee formation. I came up with the x or y configuration after external fins were added to a piece of pipe and greatly reduced sag but the application requires the pipe to rotate 360 degrees. and temps nearing 2000 degrees and the rotation and turbulence make external support impossible. I just need to find out the minimum thickness of steel to make the x or y configuration. and if I need to increase the size of the pipe to maintain volume and pressure. we currently use the 1" schedule 80 but the sag makes aligning the jets difficult. hope this helps

  12. #12
    Lead Engineer Cake of Doom's Avatar
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    I think Kelly's idea of using a higher grade with a thicker wall would be the route I'd choose because you'll have to resize the pipe to maintain flow rate anyway and may also give yourself the added headache of dealing with back pressure as the liquid tries to get around everything.

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    Administrator Kelly Bramble's Avatar
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    Quote Originally Posted by Cake of Doom View Post
    I think Kelly's idea of using a higher grade with a thicker wall would be the route I'd choose because you'll have to resize the pipe to maintain flow rate anyway and may also give yourself the added headache of dealing with back pressure as the liquid tries to get around everything.
    x2 - moreover the added complexity of the internal geometry within the pipe would make calculating the flow challenging.

  14. #14
    Lead Engineer Cake of Doom's Avatar
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    Now thats settled; who's for tea?

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    Administrator Kelly Bramble's Avatar
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    Quote Originally Posted by Cake of Doom View Post
    Now thats settled; who's for tea?
    Your place or mine?

    Another thought I have is for the op to use a high pressure flexible hosing or pipe.

    Heck, let the pipe sag...

  16. #16
    Lead Engineer Cake of Doom's Avatar
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    Quote Originally Posted by Kelly Bramble View Post
    Your place or mine?
    I'll get it brewing, you grab some cups and we'll meet by the bandstand.

    Quote Originally Posted by Kelly Bramble View Post
    Another thought I have is for the op to use a high pressure flexible hosing or pipe.

    Heck, let the pipe sag...
    The OP mentions a full 360 rotation with 2000 degs (not sure what units but guessing F). Are there flexible hoses that can stand that?

    Another thought: could you not count some of the 7k psi that is being pushed thru the pipe to aide you with the sag? Not putting any sums to it but I'd imagine that trying to bend a pipe that has that sort of pressure going thru it would be a nightmare.

    Another thought: Where is this 2000 degs coming from? Rapidly heating water to that sort of temperature, in an enclosed space can't be healthy. If it is a super steam cleaner, and this is 7000 psi of steam going thru (got knows what thats throwing out at the ports) it could still help in reducing sag.

  17. #17
    Administrator Kelly Bramble's Avatar
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    Quote Originally Posted by Cake of Doom View Post
    Another thought: Where is this 2000 degs coming from?
    And is this temperature required?

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    Quote Originally Posted by phantomofky View Post
    the application is for industrial cleaning in a boiler. use a semi automated machine to deliver 7k psi thru the schedule 80 pipe. which has .203 tips in a tee formation. I came up with the x or y configuration after external fins were added to a piece of pipe and greatly reduced sag but the application requires the pipe to rotate 360 degrees. and temps nearing 2000 degrees and the rotation and turbulence make external support impossible. I just need to find out the minimum thickness of steel to make the x or y configuration. and if I need to increase the size of the pipe to maintain volume and pressure. we currently use the 1" schedule 80 but the sag makes aligning the jets difficult. hope this helps
    So let me see if I'm understanding this... The nozzles are on the end of the wand only correct? Or are they located several places along the length? (sounds like just the end...) Then you have some sort of thing that hangs onto this l o n g ... h o t ... stick of skinny tube and spins it as it goes through the boiler tubes to blow the scale and crud out.

    How about a very loose fitting collar on the tube O.D. maybe about a foot long... that has a face to it the will run into the end of the boiler tube. Then it will slide back as the cleaning wand is twirled through the boiler tube. The loose fitting piece that will hold the end up and slide back the wand will need to be supported above somehow and tied in with the unit. Maybe two independent hoists on your overhead crane bridge where one is attached to the sliding collar and the other to the driving unit. Several ways to skin that cat depending on how much you want to get into...

    Good Luck.
    Bob

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    well the pressure does help with the sag but not completely. and yes the nozzles are only at the end of the pipe. and yes its 2000 degrees f. we have used higher grade pipe and due to heat transfer and increased weight it still sags. I may just have to try the internal supports. sometimes trial and error is the best teacher. was just hoping for some suggestions as to what size steel to use in the x structure and size of pipe to use to maintain volume. I appreciate all the suggestions.

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