U-Tube Heat Exchanger Design (Butane Powered)

[Farid]

U-Tube Convection Heater (whole device pictured)


U-Tube Convection Heater (Heat Shield made transparent)


Heat Exchanger with Airflow

PREFACE:

I have no plans to make this design, and since it does me no good sitting on my computer untouched I figured why not share it. After all ideas are a dime a dozen, and I’d be honored if this inspires others who actually take things to the next step.

This design is something that’s been sitting in my portfolio for many months now. With the lotus going away, I thought now might be a good time to revisit it. It is similar to the lotus in that it is butane powered and convection based, with the heated air isolated from the butane exhaust.

Where it takes a big turn (pun intended I suppose), is the use of narrow U-Tubes in the heat exchanger instead of a plate. These tubes allow the air to be heated from all sides resulting in rapid heat transfer. The arrangement of the tubes takes advantage of counter current exchange, resulting in a more efficient heat transfer, and a more uniform mass of heated air.




U-Tube arrangement (tubes touching facilitates some countercurrent exchange)

Inspiration:

One of my main goals was to create something aesthetically pleasing, emulating devices which already are used for smoking. I considered many devices – hookahs, briar tobacco pipes, cigar shapes, the Japanese kiseru pipe, drinking cups (just kidding). I ended up going with an Iranian opium pipe called a vafoor.



Despite their dubious purpose, I find these pipes to be elegant, while also offering lots of space to design a heat exchanger to my liking. It also helps that the air path through the stem is the perfect length for conditioning the convection vapor, which often tends to be hot and harsh without water filtration.

CONTINUED IN NEXT POST...

 

[Farid]

Parts:

This device consists of 4 main components.

1) A stem which holds the bud
View attachment 6222

2) A heat exchanger housing
View attachment 6223

3) The U tubes which attach to the heat exchanger housing



4) An outer heat shield



Usage:

The device is used by heating the bottom U section of the U-Tubes, and simultaneously inhaling

It is intended to be used as a desktop. While technically portable, it is not pocketable, and it was designed to be used with a stationary desktop butane burner (like the yama/rekrow butane burner pictured below).



It could also be heated with any flame heat source, but it would be easier to use with a stationary heat source so as to be hands free. With some modification to the heat shield it could also be used with an induction heater too I suppose.

Please let me know your thoughts. Again, I’m not planning on making this or selling it, but maybe it can offer somebody somewhere some inspiration.

 

[Abysmal Vapor]

That's a nice concept ! Reminds me a bit of the ancient Celticvapo .

 

[Farid]

^Wow I've never seen that one before. The main difference with that one is that you heat, then hit versus this would be more like a lotus, where you hit and heat simultaneously.

Been revisiting this idea after reading the lotus thread. Thinking about just biting the bullet and buying a lathe

 

[Abysmal Vapor]

Thinking about just biting the bullet and buying a lathe

Do it ! I am definetly up for one of these !

 

[GI]

I like the idea, and the design what kind of U tubing ?

 

[Farid]

Just bent 316 stainless most likely

 

[Farid]

Here's another play on the same idea. This time in a different format. This one has a retractable heat shield that can lock in place like a bolt action. But it would need to be heated with a pocket torch.