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Hypothetical near boiler piping idea

STEAM DOCTOR
STEAM DOCTOR Member Posts: 1,465
Good morning. Trying to pick some of the steam brains. Let's say , for arguments sake, that I have boiler piped in 3". 3" header, 3" riser from the boiler.....But I am not confident that steam will be dry (exit velocity is higher then desired...). Is there any benefit or drawback to adding a 6"-3" coupling with a 6"-3" bushing, to create a steam separator, essentially a 2nd, external steam chest? The bushing will be on the top of the coupling to prevent water from pooling at the bottom of the coupling. Obviously more and bigger boiler risers and a bigger boiler header are ideal. But for argument's sake let's say that's not an option. This whole contraption will cost under $250. Any thoughts would be greatly appreciated.
 All of the numbers above are purely arbitrary.

Comments

  • SteamingatMohawk
    SteamingatMohawk Member Posts: 722
    What is your exit velocity based on? What is the number?
    How many risers?


    ethicalpaul
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,465
    The above scenario is made up. It's a figment of my imagination. Let's say for argument's sake that the exit velocity is 25 ft per second and circumstances prevent extra boiler risors or a larger header. Is there benefits to the above suggested addition. 
  • Jamie Hall
    Jamie Hall Member Posts: 18,699
    Not quite clear on what you are proposing here. Where is this 6x3 coupling going, and what does it attach to? If it's just the coupling and then immediately the bushing, and it's on a vertical line, there will be very little benefit if any -- any water droplets which come out with the reduction in velocity will fall back down to the bottom of the coupling and immediately be re-entrained. When enough water is trapped that way, it will carry out the top no reduction in total volume of water.

    Steam drums or steam separators are wonderful, but they be big enough to really reduce the velocities and, perhaps more to the point, the geometry and connections have to be such that there is a real separation taking place between water droplets -- which fall, though slowly, and don't turn corners really well -- and the steam. This is one reason why a header a few feet long, one size larger than the risers (which need to be full size) works so well. Steam and water come whistling in one side near one end and the water tends to impinge on the opposite side , then drop in the slower flow and flow to the other end, where it drops to the equalizer (or other drain) while the outlets, near the top, really pick up only steam. while the water droplets just fly on by below. The greater the velocity difference the better, but there is such a thing as overkill.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,465
    There is a company (in New England, I think) that makes/made an external steam separator. I am trying to make my own separator. 
    ethicalpaul
  • ethicalpaul
    ethicalpaul Member Posts: 3,707
    edited May 11
    I don't think the droplets would be retrained. If they hit the wall of the pipe they are very unlikely to get picked back up off of that. An oversized header does the same thing...it temporarily reduces velocity which will then increase again after the header.
    1 pipe Peerless 63-03L in Cedar Grove, NJ, coal > oil > NG
  • ethicalpaul
    ethicalpaul Member Posts: 3,707
    I'd love to see a sketch of your proposed separator as it would be installed
    1 pipe Peerless 63-03L in Cedar Grove, NJ, coal > oil > NG
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,465

  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,465
    Dan mentions such a device in Lost Art (that's where I got the idea). Steam anti surge tank. Was thinking to put it on vertical riser coming out of boiler. 
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,465

  • Steamhead
    Steamhead Member Posts: 15,263
    By the time you've spent the time to engineer this and bought the materials, you've probably exceeded the cost of a new anti-surge tank..................
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,465
    @Steamhead. About $250 or so. One coupling and one bushing. Takes a few seconds to screw together 
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,465
    And you save a few pennies on the boiler riser. The 6" coupling ( or whatever size one might use), accounts for some vertical rise. 
  • ScottSecor
    ScottSecor Member Posts: 547
    They used to push these steam separators at a local supplier made by Union Steam. http://www.unionsteam.com/

    We prefer to keep it simple and follow standard piping practices.
  • Jamie Hall
    Jamie Hall Member Posts: 18,699
    A VERY important bit of the design of those steam separators may not be completely obvious: the outlet protrudes significantly INTO the separating chamber. This geometry will sharply reduce the degree of re-entrainment in the outflow. An additional modifcation -- though not really needed, perhaps -- would be to have the inlet arranged to enter so the flow is tangent to the side wall, and have a bottom relief for the separated water in the manner of a standard cyclone separator. But I think that's overkill. The protruding outlet pipe, though, is I think essential.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    mattmia2
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,465
    I am looking for a solution where there is either limited space or limited resources. Not instead of good piping. In addition to good piping. As always, my ears are open.
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,465
    edited May 11
    I could always add a double tap bushing, to create my own drip leg. Apparently, the steam separators are still out there. I am reluctant to use them, because they only come come in 2". I can't say that I am comfortable enough, to reduce recommended pipe supply size. I am looking for an additional to proper piping, not a replacement. 
  • Jamie Hall
    Jamie Hall Member Posts: 18,699
    I'm a simple minded soul. So what I'd probably do is go to a 4 inch header and call it good...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    ethicalpaul
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,465
    @Jamie Hall. Bigger header has been and will continue to be my go-to option. However, there are situations where every inch makes a difference. 4" T's are obviously bigger then 3" T's, for example. And a single separator can cost a good bit less then larger pipe fittings. Just trying to think a bit out of the box.  
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 11,900
    edited May 12
    I think a steam separator has limited value. If the boiler water is dirty you going to have operational (surging) problems with the boiler even if you do dry the steam to the building
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,465
    Back to the retrain issue. Do we really care if the the water retrains at the inlet, as long as the steam is dry at the outlet?
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,465
    @ethicalpaul. You probably have some extra time this summer. Maybe some experimenting?!? Separator without dip tube and with dip tube at different insert depths. Essentially, different lengths of nipples. 
    ethicalpaulmattmia2
  • ethicalpaul
    ethicalpaul Member Posts: 3,707
    haha I love the suggestion! But my boiler won't launch any water droplets even with a single 2" supply pipe.

    I know you mentioned lack of space, but I think I'd rather see an undersized horizontal header than that vertical separator.

    I take back what I said about droplets not being re-entrained...I think they would with this one...it reminds me too much of a percolator. I want to see the equalizer more in the path of the water's general direction as it gets carried by the steam.
    1 pipe Peerless 63-03L in Cedar Grove, NJ, coal > oil > NG
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 2,983
    edited May 13

    haha I love the suggestion! But my boiler won't launch any water droplets even with a single 2" supply pipe. .

    Com'on Paul... You could repipe one of those risers to an 1-1/4 riser to induce the needed velocity. Then you can buy another 1-1/4 glass observation section. Since you are independently wealthy and nothing better to do.

    Trying to shame Paul into getting you an answer @STEAM DOCTOR (hope it works) >:) I love his videos!
    Edward Young
    Retired HVAC Contractor from So. Jersey.
    Services first oil burner at age 16
    P/T trainer for EH-CC.org
    ethicalpaul
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,465
    Took this off a boiler a few years ago. Some sort of external steam separator. 
  • delcrossv
    delcrossv Member Posts: 502
    edited May 17

    Took this off a boiler a few years ago. Some sort of external steam separator. 

    You'd think you would want the steam inlet and outlet to be at opposite ends. (?)
    Is there a baffle inside?
    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
    ethicalpaulmattmia2
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,465
    Yes. There is/was a baffle. Steam would enter the left side, move right, water would drip back into return, steam would make a union above the baffel and exit out top left. 
  • mattmia2
    mattmia2 Member Posts: 5,279
    Seems your limited space problem has already been solved with the drop header...
  • Tim_D
    Tim_D Member Posts: 66
    Frank Gerety was a smart guy. I did a motel out in the Hamptons in 1981 or 1982 where Frank designed a seasonal change over chilled water, hot water system piped primary secondary. I thought he was on drugs until he was kind enough to draw it out and explain it to me.