Kryptoknight wrote: (clip) i was thinking about welding a 3" pipe between them near the top of the tanks.(clip) ^^^^^^^^^^^ Wouldn't it be better to put the 3" pipe near the bottom? That way, when you use the oil, both tanks will be emptied.
I'd be inclined to rig a manifold on the fill pipe that splits the incoming flow between the two tanks, and leave seperate lines teed together with valves to the supplied device, that way if you ever have a line break or a tank leak you will only lose half the fuel and you can replace the bad tank without further modifications.
The simple, straight forward, problem-less prone way is to simply have two fill tubes and vents. The oil man will have no problem with that. Over the years I've concocted many "clever" solutions only to have some of them come back to haunt me. I've learned that there's often very good reasons for doing things the standard/ordinary way.
Take a lesson from the semi trucks......cross over line at the bottom and vents on each tank. I wouls also make it with a bolt on flange and valves in the line in case of a future problem with a tank or if you need to drain one for any reason. The vents can be had at any heavy truck dealership. I would use a hole saw for the opening. Another thing that has been done on trucks is raise the crossover an inch or two from the bottom and put the draw tube right in the crossover line. That way any dirt or water sinks to the bottom and all you are sucking in to your furnace is clean fuel.
I would check with my supplier first to see if they had any concerns or recommendations. Oil companies are quite nervous about being held liable for oil being inadvertently placed in the environment. Shame to do a lot of work and then find they won't fill it for you.
Just a thought about safety - are these new tanks? If you weld on old tanks, there could be an explosion when residue vaporizes and then explodes. I had a story told to me where a fellow was welding and died from the resulting explosion of an oil tank due to fumes igniting.
i would not attempt this. the ends of the tanks provide vital support when tank is full, plus i have no good way to pressure test it (thats why i would put join tube at the top where pressure is minimum).
i may just opt to create some sort of split in the fill tube, perhaps the safest way.
"Kryptoknight" wrote in news:AD6yb.356814$ email@example.com:
(eyes crossed, ok Krypto, let me have another beer)
But it could be done without TO MUCH trouble. Instead of cutting the end sheets out completely flush with the sides, you could cut the ends out leaving say, 2" of steel all the way around, and clamp the two tanks together, with pipe clamps, or use angle clips and C-clamps, or dogs and wedges to pull the tanks together,(depending on what ya have and what ya don't) tack weld around the seam, weld the seam, and it would be plenty strong enough for its purpose. They have footing brackets on the bottom of the tanks if I remember right for support of the tank, two at each end, which would leave you with four footing brackets in the center after joining. If you really wanted to get carried away, you could wrap the joint with say a 2 1/2" wide strip of 12ga. and weld it over the joint. No need really. To test the tank put a 2" pipe plug in one filler coupler that you drill a hole into, and use rubber tip air blow gun to fill the tank with a little pressure, plug hole. (the other openings would be plugged and valves tuned off. Dilute some dish washing soap with a little water, and apply to welded joint with a small paint brush. If there are any holes, there will be a stream of bubbles. Over kill to some, but If it were me, I would weld the two together.(2 hrs max from start to finish) But that's me, you do as you feel it should be done. =-) We all have our ways. lol!
With the joint on the top, you have to be careful that the natural flow of oil between the tanks will be greater than the pressure pumped oil into the first tank, otherwise it will come spewing out the vent making a huge mess......so maybe at the bottom would be a better choice (not only would the transfer have more time go even out, the pressure of the oil at the bottom of the tank would help to push it into the other side)....