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  1. #1
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    Danfoss stop valves flow direction



    Danfoss Industrial ammonia stop valves.
    Any preference for direction?
    Reasoning for that.

    Thanks



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    Re: Danfoss stop valves flow direction

    Do you have a valve model/type as there are different preferences for different models.
    Brian - Newton Abbot, Devon, UK
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    Re: Danfoss stop valves flow direction

    To achieve optimum flow conditions, the valve should be installed with the flow towards the valve cone as indicated by the arrow on the side of the valve body. Flow in the opposite direction is also acceptable, but slightly reduces the kv- / Cv value.
    -Cheers-

    Tycho

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    Re: Danfoss stop valves flow direction

    Hi
    direction of valves
    zzzz.jpg

    all valves should install in right direction.
    seat of valve( Teflon ) has more pressure and get damage in long time
    Last edited by mbc; 08-04-2019 at 05:51 PM.

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    Re: Danfoss stop valves flow direction

    Quote Originally Posted by Brian_UK View Post
    Do you have a valve model/type as there are different preferences for different models.
    Brian SVA in general, also SVA250 & 300 valves

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    Re: Danfoss stop valves flow direction

    Quote Originally Posted by mbc View Post
    Hi
    direction of valves
    zzzz.jpg

    all valves should install in right direction.
    seat of valve( Teflon ) has more pressure and get damage in long time
    Thanks, do you ever consider gland when valve isolated.
    Sometimes when valve isolated to repair say a solenoid etc, gland is on live side.
    If you had strainer removed for example & gland started to leak you could be in trouble.
    Last edited by RANGER1; 10-04-2019 at 08:35 PM.

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    Re: Danfoss stop valves flow direction

    Quote Originally Posted by Tycho View Post
    To achieve optimum flow conditions, the valve should be installed with the flow towards the valve cone as indicated by the arrow on the side of the valve body. Flow in the opposite direction is also acceptable, but slightly reduces the kv- / Cv value.

    Tycho,
    With ICF valve stations Danfoss don't seem to worry about valve direction!
    I understand with single stop valves as you have stated.

    http://files.danfoss.com/technicalin....A7.02_ICF.pdf

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    Re: Danfoss stop valves flow direction

    Hi,

    Everyone agrees that the stop valves should always close against the flow(flow to open configuration.

    This type of flow direction lets the disc to rotate freely on the valve stem. This allows the disc to fit properly against the seat as the valve closes, which results in less seat leakage
    It won't expose the PTFE glands or packing directly to high-velocity flow.
    It won't cause impurities to trap on top of the disc thus plugging the stem movement.

    But check the image from Danfoss. Its a hot gas defrost line and they put stop valves in both directions.
    valve.JPG

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    Re: Danfoss stop valves flow direction

    Not everyone uses valves this big, but more common.
    See page 6
    could be a trap when working on system if pressures build up.
    The DL is mostly used as is a lot cheaper.

    http://files.danfoss.com/TechnicalIn...1/rd7as122.pdf
    Last edited by RANGER1; 16-04-2019 at 08:50 AM.

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    Re: Danfoss stop valves flow direction

    Quote Originally Posted by RANGER1 View Post
    Not everyone uses valves this big, but more common.
    See page 6
    could be a trap when working on system if pressures build up.
    The DL is mostly used as is a lot cheaper.

    http://files.danfoss.com/TechnicalIn...1/rd7as122.pdf
    We mostly use larger valves like this on liquid separators, and on those I always have the valves positiones so the that if the pressure rises in the tank it will push the seat towards closed.

    I worked with a technician 20 years ago that was insisting that it should be the other way around so that you wouldn't rip the teflon seat off when opening the valves.

    in 22 years I've never had that happen with a main valve.
    -Cheers-

    Tycho

  11. #11
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    Re: Danfoss stop valves flow direction

    Quote Originally Posted by Tycho View Post
    We mostly use larger valves like this on liquid separators, and on those I always have the valves positiones so the that if the pressure rises in the tank it will push the seat towards closed.

    I worked with a technician 20 years ago that was insisting that it should be the other way around so that you wouldn't rip the teflon seat off when opening the valves.

    in 22 years I've never had that happen with a main valve.

    Tycho, thanks for reply, you used to man of many words, now man of few words!

    These particular Danfoss valves have two valve seats, one smaller one to allow easier opening against pressure.
    In real terms valve direction is not critical if sized correctly or not.
    I personally don't like the idea of valve gland live on liquid lines or hot gas.
    While servicing & it later leaks, your in trouble straight up while you are cleaning a strainer, solenoid etc.
    Last edited by RANGER1; 16-04-2019 at 09:06 PM.

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