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  1. #1
    Forum Member KEEPBACK200FEET's Avatar
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    Default Dual Dumptank Operations?

    I'm really confused about something. I overheard some guys talking the other night about a situation where you can drop two dump tanks, put the hard suction with the low level strainer in one, connect and charge a hose to the the coupling on the side of the strainer and create a steady flow of water into and out of your pump, and also create a steady flow of water between the two pools. I've racked my brain trying to figure this out.
    Last edited by KEEPBACK200FEET; 06-15-2006 at 12:47 AM.
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  2. #2
    Forum Member RLFD14's Avatar
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    We do this once in a while when the situation dictates, but without the recirculating thing you mention. The driving concept is a way to tie two (or more) dump tanks together to allow a larger on-site water capacity. This allows three things to take place:

    * Increased on-site dump capacity gets your tankers emptied and on their way to refill earlier.
    * Increased on-site water supply provides insurance in case the water shuttle operation is for whatever reason interrupted.
    * Depending on placement of the two (or more) dump tanks, allows more tankers to dump simultaneously.

    The cheapest way to accomplish this:

    * Place two dump tanks side by side and fill them up at least halfway.
    * Take a section of hard suction and completely submerge it in one tank so that no air remains in the hose.
    * Lift both ends of the hard suction at the same time and elevation to hold the water in it, move one end over the second dump tank, and then lower both ends.
    * The tanks will now equalize and maintain equal water levels through siphoning action (at least until the water gets so low that air gets back into the hard suction hose and breaks the siphon).

    There are gadgets out there to make this process a little easier, in theory. One is made of large diameter PVC, sort of in the shape of an inverted, squared-off "U". In order to fill this thing with water without doing the dunk-and-lift technique, you can attach a 1.5" hose to the bottom of one end which directs the water into the appliance. When you charge the 1.5" line, it pulls water from that tank up into the appliance and to the other side, establishing the siphon effect.

    If you set it up so the 1.5" hose is pushing the water into the drop tank where your Engine is drafting from, you will in effect have just set up a form of recirculation:

    * Water dumped into drop tank #1
    * Water drafted from drop tank #1 into pump
    * Water from pump enters 1.5" hose
    * Water exits hose into appliance, on drop tank #2 side
    * Water flows through appliance, up over and down into drop tank #1
    * Repeat....

    Still, it doesn't have to be that complicated, and there really isn't any reason I can think of to continuously recirculate this way. If you set it up backwards and try to recirc, you'll end up sucking one tank dry, too. You can do the hard suction dunk-and-lift to equalize the tanks and leave it at that, the dump tanks will constantly self-equalize without your attention required. I think setting up the appliance increases the complexity and time to equalize the drop tanks, and introduces new things to go wrong.

    It isn't a bad idea to be able to attach the non-floating strainers to both ends of the equalizing hard suction so that the tanks can be drawn down as far as possible if necessary. Final caveat: The equalized dump tanks MUST be on more or less level ground and level with each other.

    Hope this helps.
    Last edited by RLFD14; 06-15-2006 at 01:59 AM.
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  3. #3
    Forum Member nmfire's Avatar
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    Default

    The short short version:

    You are creating a syphion from one tank to the other. The Jet-Syphion attachment on the low level strainer is what gets it going. Once it starts, it probably won't be needed to maintain it.
    Even the burger-flippers at McDonald's probably have some McWackers.

  4. #4
    Forum Member bfranse's Avatar
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    The Jet Siphon works using the Venturi Principle, just like a foam eductor.
    We're not spliting rocket hairs here people!

    Training is like building a pyramid, if you want it to last, you don't built it pointy side down!

  5. #5
    55 Years & Still Rolling hwoods's Avatar
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    Thumbs up Been That, Done There..............

    1. Set up one dump tank, Fill with water. Have Engine draft from tank.
    2. Set up additional Tank(s), Fill with Water. Place one or two hard suction sleeves over rails so both ends are submerged in adjoinding tanks.
    3. Pull a 150' 1.5 in. preconnect and charge it. Direct the hose stream up through each sleeve long enough to establish the syphon effect.
    4. There is no limit to how big you can make this system. One Fire, some years back, We maintained a 600 GPM flow for almost two hours.
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  6. #6
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    Default

    Portable water tanks can be set up in any number to allow for greater water flow and storage. A device called a "siphon jet" is used to transfer water from one tank to another. Each siphon needs a dedicated 1.75" line to power it. The flow ratio varies by the pressure used in the jet. You use part of the water you are drafting to power the jet. The more water you need transferred, the higher pressure you send to the jet. You always keep your booster tank filled to start a jet if a tank runs dry. There are various tank set-ups that work, you just have to have a sharp pump operator to mange the jets. In some multiple tank set-ups a smaller truck like a mini-pumper is used to support all the jets which allows the pump operator to pay attention to the firefighting effort.

  7. #7
    Forum Member KEEPBACK200FEET's Avatar
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    Default

    Thanks guys, this makes PERFECT sense now.
    Just know, I chose my own fate. I drove by the fork in the road and went straight.

    Quote Originally Posted by FlyingKiwi View Post
    Go put your pussy 2 1/2" lines away kiddies.

    Quote Originally Posted by Explorer343

    By the way KEEPBACK200FEET, you're so dramatic!

  8. #8
    Forum Member RLFD14's Avatar
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    Two things:

    (1) I didn't know it was called a siphon jet. Thanks.

    (2) This thread is a stark reminder to myself that I say too much most of the time. Less is more.
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  9. #9
    Forum Member Bones42's Avatar
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    Quote Originally Posted by hwoods
    3. Pull a 150' 1.5 in. preconnect and charge it. Direct the hose stream up through each sleeve long enough to establish the syphon effect.
    Can't I pull less hose? I mean, the damn engine is sitting right next to the tank, can't I just pull a 50' length?
    "This thread is being closed as it is off-topic and not related to the fire industry." - Isn't that what the Off Duty forum was for?

  10. #10
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    My old vollie department's AO had enough hydrants that we only practiced dump tanks and some guys(newer than me) figured we'd never need it.
    Good thing we had the practice one breezy day during the wildfire season.We had our closest mutual aid come from the next county over that time and they had to set up to do two tanks because where our engine was parked was too narrow for the tanker to get in to dump.
    You never know when or why you're going to need a skill.That's why they call them "Essentials",right?

  11. #11
    Forum Member Weruj1's Avatar
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    as everyone else says ....................its a jet siphon ! they do work well !
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  12. #12
    Forum Member Haweater's Avatar
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    Default

    We've used the 2.5" hard suctions to syphon many times, just had a practice on it two weeks ago. You don't have to lift both ends of the suction line though:
    Completely submerge a 2.5" in the tank with the most water making sure there is no air trapped in it; on the male end - place your hand over the end sealing the end of the hard suction as good as possible; QUICKLY pull the end out of the water and get it low in the other tank as fast as possible before too much air leaks past your hand - remove your hand and you have a syphon. With large draw, you will likely have to use more than one suction line; I've used as many as four to syphon between the two tanks when pumping a lot of water.
    Practice getting a syphon started this way, it's not rocket science but it does take practice to get the male end transferred to the second tank without letting too much air in the line.
    Finally, it's much easier to get the syphon started when one tank's water level is substantially higher than the other because you can see the water pouring out of the suction line when the syphon works.
    Cheers,
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  13. #13
    MembersZone Subscriber dday05's Avatar
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    Default

    I usually set up 3 tanks, I make my middle tank primary, and set up the water wynch in the other 2, that way if things go cow sh#% My people will have water to get out of the enviroment that they are in or what not, because you know how a water shuttle opp can go sometimes,so it's nice to have that extra water.BE SAFE

  14. #14
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    maybe some pics might help you a little bit better, this was an ISO water shuttle we was at a few years ago http://polandfire.dnsalias.com:8888/...ll/page_01.htm

  15. #15
    Forum Member KEEPBACK200FEET's Avatar
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    Thanks for the pictures dude. They really helped out alot.
    Just know, I chose my own fate. I drove by the fork in the road and went straight.

    Quote Originally Posted by FlyingKiwi View Post
    Go put your pussy 2 1/2" lines away kiddies.

    Quote Originally Posted by Explorer343

    By the way KEEPBACK200FEET, you're so dramatic!

  16. #16
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    Quote Originally Posted by nmfire
    Once it starts, it probably won't be needed to maintain it.
    Is that because the pump sucks the water from the tank?
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  17. #17
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    Siphon operations are something we should put on our list of things to phase out of routine operations over the next 20 years or so.

    There are better ways -- simpler, less maintenance/watching/tinkering, less manpower (or brain power) needed. Tanker shuttles take enough effort if you're pushing them to the limits without having to setup and maintain the siphon system.

    Connect the drains.

    Fold-a-Tank makes a commercial unit to do this between their 10" drains.

    There is one disadvantage -- all tanks rise and fall together. This could affect your ability to draft out of the near tank...if you have three connected and they're all low.

    My guess is it's rare you'd have that situation to have a big enough fire to need a 2 or 3 or more tank shuttle, but not enough tankers to maintain a drafting minimum in all of them but only one.

    The situation could be mitigated if you use a clamp or ball valve to close off tanks if you're running short on shuttle capacity.

    However, I believe the simplicity of this solution (connecting drains) is far better than a more complex evolution of hooking up and monitoring jet siphons.

    Until we all have the drain connectors and adapters to mate everyone's tank to everyone elses...need to continue practicing the jet siphons.

  18. #18
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    You are creating a syphion from one tank to the other. The Jet-Syphion attachment on the low level strainer is what gets it going. Once it starts, it probably won't be needed to maintain it.

    Siphon will only operate by itself if the water level in the "supplying" tank always remains above the tank you're drafting from.

    Seems unlikely to me, and also means you can't take advantage of the capacity of the tank you're drafting from to give you an additional buffer since if it's level ever gets higher than the supplying tank, a natural siphon would stop.

    And hope no one dumps a load in the tank you're drafting from and reverses the siphon :shock:

    So while theoretically possible, in practice jet siphons are operated in "jet" mode all the time, fed by a handline


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    On a seperate note, is firefighting the one time "sucking pond water" is a good thing

  19. #19
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    Exclamation

    One thing you may want to do if you have a jet siphon is keep the end of the suction line that is going into the tank you are drafting from at rim level. In other word keep it above the tank you are siphoning from. This will help prevent the suction from changing direction. This tend to happen towards the end of a fire when the water demand is down.

  20. #20
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    And what do you do if Zee Beeg One does hit and you are left with no water in the hydrant because the city water pump system is totalled by all the tremors?
    I don't think any engine crew can put out enough urine fast enough even when faced by that problem to deal with it.
    As I said earlier,my friend,"Essentials".

    Quote Originally Posted by Dalmatian190
    Siphon operations are something we should put on our list of things to phase out of routine operations over the next 20 years or so.

    There are better ways -- simpler, less maintenance/watching/tinkering, less manpower (or brain power) needed. Tanker shuttles take enough effort if you're pushing them to the limits without having to setup and maintain the siphon system.
    .

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