Thread: Linking Drop Tanks
03-28-2001, 09:29 AM #1N2DFireFirehouse.com Guest
Linking Drop Tanks
To me this topic is like Big Foot - I keep hearing about it, but I've never seen it.
I have heard about departments that link 2 drop tanks together by joining the drain chutes of the 2 tanks together.
Would someone out there who is doing this please explain this procedure (in some detail) to me.
Thank you in advance for your help.
Take Care - Stay Safe
03-28-2001, 09:31 AM #2nomad1085Firehouse.com Guest
I've never heard of using the drain chute to link them, all I can see it is something coming loose and there goes the water. I have heard of (but not done myself) using a Jet Syphon to move water from one tank to another.
03-28-2001, 09:57 AM #3chief4102Firehouse.com Guest
The simple way to do this is to use a 4 foot long piece of 6 inch PVC pipe. this is placed in the dump chutes of both tanks (of course the chutes are pointed toward each other) and an elastic bungie cord is wrapped around each of the chutes/pipe. There will be very little leaking of water and it is quick and easy to do, usually BEFORE the tanks are filled. I saw this done by a department on the coast of Maine when vacationing there a number of years ago, and thought "what a great idea". Hope this helps.
03-28-2001, 09:59 AM #4scottbcptwrFirehouse.com Guest
My department some times links two tanks together at live burns using a piece of pvc pipe and wire ties through the drains but this tends to leak a little. And is also very time consuming. I would like to hear from the departments that use the Jet Syphon as to how quick you can implement it on a fire scene with as little man power as necessary.
03-28-2001, 10:44 AM #5xenophon13Firehouse.com Guest
When we use our drop tanks we use a little gadget we call a water winch. Take a 2 1/2" hard suction hose hook an adapter to it allowing the booster line to connect into it. That way the water from the booster line pulls the water in one drop tank into the other. If you need the water to move faster get another 2 1/2 hard suction submerge it in the tank with the most water till it has been filled, form a seal around one end either with the cap, or using a small rubber ball and move it to the other tank. You can add more as needed. I am not sure if the adapter we use for the water winch is something we made or if it is manufactured by some company but it works none the less. Doing a mobile water class we managed to flow 500 gpm for over 4 hours using only a 1200 gallon tanker and a 2000 gallon tanker running about 1.2 miles each way. It got kinda scary on a few occasions but we did it.
When the defecation hits the oscillation I'll be there.
03-28-2001, 11:59 AM #6cfr3504Firehouse.com Guest
The only way I've ever seen to connect 2 drop tanks, is to place a piece of hard suction (4" is only thing I've seen used, but I guess anything would work) with the ends in both drop tanks, then take a 1 1/2" with the nozzle dialed to straight stream and place it just inside the end of the hard suction. This creates a suction and the water will flow from one tank to the other. When the water is flowing good you can take the hose out, unless the water level drops below the hard suction and you loose the "prime". I've only done it in a class though, so I really don't know how well it works on the fire ground. We've only got one drop tank, so I haven't gotten a chance to try it yet.
03-28-2001, 12:10 PM #7LHS*Firehouse.com Guest
Go to isoslayer.com
You'll see on the picture page under shuttles how we connect as many as many 11 4000 and/or 5000 gallon tanks together.
We use a drain connector clamp and bar clamp. All commercially available by Fold-a-Tank. $200 ish. It requires having a 10 inch drain on at least two side of your drop tanks. You can connect tanks together even after one or more already have water in them. The 10 inch drains have been able to support shuttle flows in excess of 2000 gpm without using any pumper lines.
ISO deducts for transfer device inefficiency and subtracts pump capacity when the pumper is is used to transfer water. They will measure how much water you are leaving in the tank with your transfer devices. We got a Class 3 rural grade using the connector clamps and bar clamps.
It is far simplier than using PVc and postmaster buckles but that is a low cost option but is limited to connecting two tanks together unless you bought tanks with multiple drains. It also works better than any inch worm assembly and does not reauire monitoring by the engineer or overflow. If you are shooting for flows in the 4000 gpm range the web page will show how to make a transfer device in the connectors using a floating pump.
As far as something letting go and there goes your water, that is what the bar clamp is for. If something goes wrong you can clamp the drain. At worst you lose one load of water. A far better idea when using more than one tank is to simply run two suction lines off the pumper. One to each drop tank. www.isoslayer.com shows how Rattlesnake CO uses as many as four suctions at one time to four tanks, plus they also use drop tank connectors and bar clamps. They earned an ISO Class 5 and will soon have a Class 4.
The procedure for drop tanks and clamps is to set the first drop tank up with the drains facing the most like direction the next tanks will be positioned.
Then fill the tank as soon as possible like any shuttle. The connector clamp rings are left attached to each drain and are clamped shut using the bar clamp.
The next tank is is positioned so the drains are fully stretched out. The tank is filled and the bar clamp released equalizing the tank levels. From this time on it is best to only dump in the second and thrid drop tanks if flows are high to reduce the whirlpool effect in the drop tank.
Each additional tank is done the same way.
A 10 inch drain has 3 times the area of a 6 inch piece of PVC. SO you can expect a huge difference in flow. The time difference between the two procedures is dramatically different. The connector clamp setup allows instant use of the drop tank where the other option has to be built first a 5 minute plus job.
As compared to a 2 1/2" water witch he difference in flow capability is 7 to 10 times higher with the 10 inch drains due to a 16 time larger surface area. The 4 inch version has a flow range on roughtly 700 gpm versus 2000 plus with the drains due to a an area that is over 6 times larger. With the water witch concept someone has to monitor the lines or risk overflowing the tanks. It also requires the engineer to pay attention to something other than the fire.
[This message has been edited by LHS* (edited 03-28-2001).]
03-28-2001, 12:12 PM #8BFD847Firehouse.com Guest
I am going to have to read again. I have done a jet siphon like explained above but can't remember exactly how we did it.
I have also seen "J" tubes used. These can be made from PVC pipe. They look like a U with elbow on the bottom of each side. You set your tanks next to each other placing the open ends in each tank. I think the ones we used were 3" but we had to use four of them and still had trouble pulling all the water from the second tank before running the first tank dry. I think larger diameter would have worked better.
The 6" link idea sounds like it would work great, but it's highly unlikly in our area that you would get two portable tanks to the scene in time to link them like these before needing to dump water.
03-28-2001, 01:17 PM #9scottbcptwrFirehouse.com Guest
Im very impressed with your shuttle operations. As soon as we get the department on the net I can show them your site. Im sure we can use some of your ideas. As one of our next steps will be trying to lower our rating. But we have a long long way to go. Thanks for the info.
03-28-2001, 02:33 PM #10EastKyFFFirehouse.com Guest
On jet siphons...
Timewise, it just depends on skill. A dept. where I used to serve had 4 1/2" hard suction on each tanker with a jet siphon already screwed in. Another good step would be to have the 1 1/2" hose attached to the jet siphon and doughnutted.
To deploy, you would just drop the siphon end into the source tank and aim the empty end into your drafting tank. You could then unroll the hose and connect to the truck. Charge the line and the water transfers very quickly.
LHS is right; it does use up some of your pump capacity. And just any old knothead engineer cannot do it right. But it has been very effective for my old FD.
Sad to say I have never heard of connecting the drains, but I like it!
03-28-2001, 02:50 PM #11spongeFirehouse.com Guest
We use a transfer device, which works on the same principle as the hard suction method already mentioned. It hooks to the wall of the tank. A line is connected to the bottom, which is the water of the second tank. The flow from the line (connected to a discharge) pulls water from the second tank and dumps it into the first tank, which you are drafting from.
03-28-2001, 03:28 PM #12RJEFirehouse.com Guest
We did it for years by connecting the drains. W/one 4000gal tanker and one similar M/A, on rural fires it was normal to set up two 2500gal fold-a-tanks (both carried on the tanker) and set them up connected. Two guys on the tanker plus the engineer on the pumper (maybe, not always available) could do it in 2-3 minutes. Set up one, clamp drain, start tanker dump, set up second and connect to the other drain and open the clamp. We got to where everyone on the dept. could do it before the first tank was full (one qualled driver plus one FF who had gone through training on this setup).
At that point, the tanker boogies to the fill site and the second FF goes to the scene. When the M/A tanker showed up, they connected their drop tank(s) in line w/ours. We practiced this in M/A drills and used it on several occasions, and never had a problem. Unless it was a long way to water, the first tanker was often back before the second was done dumping, so we'd end up w/4 full tanks (10,000 gal) unless we were flowing an awful lot of water. We only had 8,000 gal worth of tanker, but all pumpers had at least 1000gal tanks, and would dump their water as well.
We never had a problem with leaks (you use a little, but not a huge amount. And if we did "break" a connection, we had the clamps ready to shut it off.
03-29-2001, 01:18 PM #13N2DFireFirehouse.com Guest
Just wanted to say thank you for those of you who have replied thus far.
I know that the 2 tanks we have are new Fold-A-Tank brand tanks, but I'm not sure of the chute size. I am going to look into getting a couple of the bar clamps & a connector to evaluate, but I think this is going to be a step in the right direction for us.
Take Care - Stay Safe
03-29-2001, 03:43 PM #14KGMFirehouse.com Guest
If I am not mistaken, the valve that looks like a "U" is called a shoemaker valve. We just call it a tank leveler even though it does much more than that.
It has a jet siphon that can transfer the water completely from one tank to another, which is important if your tenders can dump water faster than your tanks can level. It takes two people to run, one to pull the valve out to stop the siphon and the engineer on the engine supplying water to turn on and off the jet. Works great!
To get our fastest times on a tanker/tender shuttle we set up two 2000 gal. or greater portable tanks. we also have a strainer with a foot valve. This way we can dump water backwards and and are ready to start a draft immediately when the first tanker dumps. We keep the tank full that the engine is drafting from with the shoemaker valve so the other tanker/tender can be dumped into the empty tank.
04-07-2001, 07:24 PM #15toddmcbrFirehouse.com Guest
In my area, all departments use water jets or jet syphons. They are simply a piece of PVC with a booster or 1.5 hooked up to it on the bottom end. We use them the most on mutual aid incidents. We also participate in 3 to 4 elevator burns a year. This is where we really move water. We have had up to 15 drop tanks linked together using water jets. There are some pictures on our web site of this.
Go to Pictures>Alton and browse through the pictures.
Pictures 3,8,21,22,25 & 26 show this the best.
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)