double tube heat riser

Just built a quick and simple pocket rocket to see how well it worked as seeing is believing, and all I can say is incredible! I want to build a rocket mass heater and need advice. Instead of using a single 6 inch heat riser could you use two 3 inch pipes sistered up, such as a double barrel shotgun, dual exhaust, etc. This would have the same area. Could this balance out the flow characteristics and even out the 'pulses'

Erica or Ernie can tell you more than I can, but the two 3" tubes have half the area of a 6" tube. If you had 4 pipes to give the same area, the flow would still be much less, as flow is a radius^4 function. So the flow in a 3" pipe would be 81, 4 x 3" pipes 324, and a 6" pipe 1296 so 4 of the 3" pipes will allow 1/4 of the flow in a 6" pipe.

As stated above the flow isnt the same. and getting the flow to evenly distribute would be impossible as i understand it. this is a good idea for an experiment that you do in the back yard but till its proven i would not put it in my house.

If you dont want to experiment with the multi tube idea do you mind if i try it out? yes pocket rockets are impressive I love to tach folks who live in yearts (sp) how to make the low 55 gal drum version for cooking and heating. it changes lives in a big way and it makes me happy to see folks suddenly realize that yes a yeart is a mobile home; yes you can be actually comfortable, without lugging around half a ton of box stove.

Ernie Wisner wrote:.............yes you can be actually comfortable, without lugging around half a ton of box stove.

That's the sort of thing that the tent cities in the US need teaching too.

Is there a low 55 gal drum cooker picture anywhere?

Thanks for the opinions guys. We have a lot of oil field castoffs that we use for fence posts, bale holders, anything you can imagine so reusing material was the idea. Think I might try a mock up and see what happens, I think the heat from where the pipes are welded together (hot spots) would cause more turbulance in the stream of air inside the insulated heat riser, we'll see, if nothing else I'll have some more fence posts. This J tube design reminds me so much of the pulse jet engines at the dawn of the jet age

Roy Clarke wrote:

That's the sort of thing that the tent cities in the US need teaching too.

Is there a low 55 gal drum cooker picture anywhere?

no i haven't drawn it up yet we have a few pictures on our Picasa site but they are from a distance. I developed the stove for a friend of ours that had a yeart and needed a cooking top as well as a good heater. now she has friends that want her stove and she threatens them with anything at hand. last i heard she moved it into her farm house she likes it so well. We can draw it up for folks its not hard to build and it would suite the tent cities well. I wish they would give us a holler as we travel this summer. We like to teach the pocket rockets and ovens to tent folks, street kids, homeless and such makes our job worthwhile. I was trying to figure out how the get the UN to let us teach in refugee camps around the world but i can seen to get through.

Ah well Erica will get to it soon or i will have my shaky drawing up soon.