Anybody ever use them?

You take a T, slide it over a little line and put a compression fitting on one end of the T. On the perpendicular part of the T you thread in whatever you want to go around the little line, and then you put a big line on the other end of the T.

So you could have a 5/8's water line inside a 13/16's fuel sender line inside a 15/16's fuel return line. I like the idea of doing it that way, as it would be super efficient heat transfer, but I feel funny about pumping fuel through a cylinder instead of an open pipe. Cross-sectionally a 13/16's line with a 5/8's line inside of it is equivelant to a 1/2 inch line, but it just seems wrong. Anybody think it'd be a problem?

Anybody think that'd be a problem if you were to use flexible lines?

Thanks for any thoughts...

 

Since you run a first gen I'll pm you a secret.

Rick

 

Ricky..!>>!..... Do you have something you want to share with the class????

OG

 

Line within a line seems like it would be prone to leaks where the inner line exits the outer.

 

I use a "line in line" in my system, usually called a "hose in hose', or HIH, vs. a HOH, which is a bundled system, not as good for heat transfer. I use a 3/8 aluminum line from McMaster-Carr, but I for my outer hose, I used 3/4" industrial heater hose. I brazed the necessary fittings on to the "T", no problems at all. Use nylon compression seals, not copper, where the inner line exits the "T".

 

http://www.fattywagon.com/fwproducts.htm

these guys sell one

 

Yup, like that.

Only they are loosing a lot of flow by only having a 5/8's line around that fuel line; I plan on using a bigger outer line to maintain the same cross-sectional flow area.

And I am planing on putting the 5/8's heating line inside of the fuel line. In theory it couldn't create any fuel problems... Right?

And another thing; what is the best way to insulate the lines?

 

I think you are right about the flow rates, that is why I used a 3/4 outer hose. If you get a list of parts (I can give them to you if needed) you will have to do some drilling to accecpt the 3/4 hose.
I hope you are planning on putting the 5/8" OUTSIDE the fuel line. If not, please explain. If so, and done well, there should be no issues.
I use pipe insulation, seems to work well.

 

I'm planning on putting the 13/16's inch fuel line around the 5/8's inch heater line... I don't know if the marginally better thermal efficiency would account for a possible restriction of fuel flow, though. That's what I would really like to pick minds about.

 

So the fuel line will be wrapped around the heater hose like a spring? If that is correct, then the heat transfer will be similar to a hose ON hose construction. The heat will have to go through the rubber, a good insulator so it will take longer to heat the oil, before it is absorbed by the metal line. As well, the metal will be touching the heater hose along one fine line.

 

No; just like the picture that I posted, only the heater line is on the inside and the fuel line is on the outside.

 

OK, now I get it, I can be a bit slow.
......but I don't see a thermal gain in the reverse set up.
From experience, with the fuel in the inside, it gets plenty hot within 5 feet. If not hot enough, add more run or a FPHE.

 

I just bought the hose in hose parts from mcmaster carr. its just a coil of bendable aluminum line that you stick inside a large 3/4" hose with some tees on the end like the image. Looks like a great idea to get more heat into the fuel, but I wonder about causing a fuel restriction with a line that small. Its outer diameter is 3/8, not the inner diameter.
The aluminum line is rated for pretty decent pressure but I didnt see a spec on vacuum. Doubt it will be a problem. Once its in place and tied down its not supposed to flex a whole lot. Id still install shutoff valves for the coolant supply in case it leaks.

 

What I was thinking was that, if the water is on the inside, then all of the heat will have to pass through the fuel before it escapes. If it is on the outside, then you might have half the heat go into the air rather that be absorbed by the fuel. Unless the line is really well insulated.

Or so that's what I'd think would happen.

The eaisiest thing to do would run a nylon coolant hose inside of a solid pipe... Should work, no?

It would be possible to put the return lines in a third pipe, but that'd be a total pia... Maybe I'll run the return lines and the heater line parallel inside of the 1-inch diameter fuel line. That should work.

And I'll also get to say I have a 1-inch diameter fuel line. You don't got nothing on The Incubator, Scheids! Hehehehehehe...

(And, as Kawi brought up, what exactly happens when one of these lines breaks? What's worse, coolant in fuel or fuel in coolant? )

 

either way, you will lose heat w/o insulation. with heat coming from inside, it will heat the fuel 1st, but you'll still be losing heat from the fuel to the environment at a faster rate than if the fuel were inside. not sure what the overall difference would be, but seems like it wouln't be much. physicists? also, if you ever had a line break, i think it would be better to have the fuel line inside so the pressure would leak more fuel out than allow coolant in???