Peter, vertical batch?

[Vortex]

Pat, that's very interesting, I look forward to seeing it in action. Let me know if you need help with the video.

[Vortex]

Mar 12, 2017 9:38:18 GMT -8 patamos said:

I'll see about making a little video

this thread has my head spinning...

woke up (too) early this morning wondering about a 9" x 9" x 18" tall vertical feed chamber...

into a 6" CSA short J-feed burn tunnel with P-plate, trip wire etc...

into a 2' (?) tall half riser...

into a second half riser ala Matt's split riser set up...

This would bring the whole set up down to cooking height, 
could solve the coles-blocking-port issue
and maybe stabilize the burn somewhat
AND (big one here) eliminate the cost of fabricating a door.

Then again, it may not work at all

Hope this doesn't feel like a thread-jack
Just tossing ideas into the mix...

Here's the video Pat. I've rotated it so it's upright and uploaded it to Vimeo.

Looks really interesting - A real hybrid - Cant wait to see where it leads

[satamax]

Thanks a lot Pat and Trev.



So you are at 1.73 CSA for the moment. Intresting.

If only i didn't have a flat to finish, a day job. And the sawmill to finish!

[satamax]

Batch box's CSA is 3.96 times the size of riser's CSA.

[patamos]

Thanks Trev and Sata

To clarify:
Batch box ix 7" x 7" = 49"sq.
Burn tunnel is 5.75" x 5.75"
Heat riser is 5.75" x 5.75" so that part of the core is = 33"sq

So the box is a little under double the CSA of rest of core.

We might say the last 3' of the 10' worth of stack 5" brings the system CSA down further.

But at the same time, now that i have the feed tube burning much hotter… i have plenty of heat left over as it heads up the exhaust.

The most intriguing part is just how much better the whole thing performed once i lengthened and capped the feed tube as i did.
Zero smoke back at every stage after lighting. No fuel load hang ups.


I'm wondering now about a 9" x 9" x 18" capped feed tube, leading into a 6" CSA short burn tunnel, splitting into 2 4" or 5" half risers… with some middle ground of batch and J port/tunnel dimensions...

Has anyone tried this?

[Vortex]

The half riser's is an interesting idea, would be good to know how it behaves with the larger feed tube on the existing setup first, so you'd have a clearer idea of how each change affects it.

[patamos]

Good idea Trev,

I'll change that one aspect first and see how it goes.

I'm thinking two risers side by side, Each 5" CSA by 24" tall.

Thinking I'll shorten the burn tunnel and create the ports by splitting the burn tunnel down the middle…

Will get onto it soonish...

[drooster]

Two risers side-by-side from one burn tunnel doesn't work,
(in before PvdB)
one of them takes over, one is left behind.

[patamos]

Thanks drooster,

Thought i had caught up on all the early threads, but i guess not.
Was that in Peter's batch box experiments? Or earlier J-feeds?
Can you point me to the thread?

Yes, i am anticipating one side taking over, but then am wondering if the other will kick in during higher fuel-burn phases…

will be good to first glean all i can from earlier studies...

[Vortex]

Systems with 2 channels do tend to bias to one or the other if they can.

I think you should be able to avoid that though, if you make sure the 2 sides are a perfect mirror image, and that the exit port is in the center. Also I would make sure the CSA's not large enough to give the stove the option of using one riser or another, then I think you should be able to make it work.

[peterberg]

Mar 21, 2017 14:42:04 GMT -8 patamos said:

Was that in Peter's batch box experiments? Or earlier J-feeds?
Can you point me to the thread?

The double riser idea was tested in a thread long before the earlier j-feed experiments, November 2, 2009 to be precise. It took some time to find it and it's just one picture and a couple of lines about this subject. The link to the relevant post is here.

Nevertheless, I know quite exact what happened. Randomly, one of the risers heated up and the other was left behind, functioning as a leak from the firebox. The whole point about rocket heaters is that all the combustible gases need to pass through a hot flame front, in such a way that none will excape oxydation.

[patamos]

Thanks for the link back Peter,

For curiosity's sake i swapped out the 6" heat riser fora 4" CSA one, 4.5' tall. with a 2" wide by 6" tall port from a burn tunnel shortened to 4" from feed tube/box.

It smoked back a fair bit and pulsed strongly during peak flame up.
Could be i was asking too much of the core with all the extra ISA downstream

So then i swapped in an 8" round riser, 20" long (adding to the 5.5" burn tunnel height.
It is doing surprisingly well. And burns happiest when i add a bit of a P-channel into the barrel side of the feedbox top door.
Still playing with it. WIll post a video after a few more burns to make sure i know what is going on...

[Vortex]

Not surprised it wasn't happy with the 4", that's a tiny pipe, the 8" has four times the csa.

I look forward to seeing the video. Happy to do the convert and upload if you need it.

[patamos]

So after playing with the 20" long 8" dia riser under various conditions… i saw that it just wasn't as reliable as the original super tall 6" riser.

Next i tried a 2' tall 6 " riser with a batch box port cut through the back of it leading into another 2' tall 6" riser… And it performed worst of all. I thought maybe the first riser would handle the ramp up and the second one would kick in as necessary when getting to full load alight.   It worked okay once it was warmed up. But super crappy too often.

So i ditched the goal of stove-top height to see how a 3' tall (plus 5.5" burn tube height) riser at 8" diameter with a 6"shorter burn tunnel would perform. At this stage just wanting to see if a more standard 1 barrel set up would be able to handle the oversize firebox and peak fuel combustion. The answer? Not as well as the original taller 6" riser. This can be seen in the video i am sending to Trev to upload (with many thanks )

I still have the 8" riser in there for now.  But don't have time to keep tweaking things.  And am getting ready for a complete tear down heading into some more experiments with Trev's vortex.

All i can conclude with any sense of certainty is that the vertical batch can pull quite well with no smoke back so long as the lid covers the forward 2/3rds of the opening
Key ingredients are a 1/4" or so slice opening up against the barrel.
And, more importantly, the P-plate and channel that Peter recommends per burn tunnel system size has an intake opening WITHIN the feed box.
Mine has been about 4 inches below the lid through all these latest experiments, and it always draws excess gasses down into the burn tunnel once the burn is going well. With the first iteration in the first video the burn ramps up very nicely.  So i would say it is a highly functional low maintenance combustion process

Whether all this will work when subject to greater harvest and lower exhaust temps… i cannot say. But would be stoked to hear about someone else giving it a try...

[Vortex]

Thanks for the update, Pat. The video is here: