[Stoves] Update on new approach: Simple natural draft TLUD

Sun Sep 10 20:37:18 CDT 2017

‎Dear Jock

You have the secondary air entering through an annular gap. ‎This provides a 'sheet' of air, circular of course, that can provide exactly the right amount of oxygen.

The problem is that although the volume is correct, it may not be well-mixed. Mixing is a separate issue from quantity.

So....try this: with a pair of pliers make a series of twists about a plier-width apart so that the edge/lip over which the air passes ‎is turned into a series of teeth, breaking up the flow into a series of 'fingers' of air. When entering the gas stream in this fashion, it will mix far better than a sheet.

It is this technique that is used with gas burner heads. Gas stoves don't have a sheet of flame, they have small jets separated slightly to get air mixed ‎immediately.

If it makes a difference, changing nothing else, the smoke should be reduced because of better mixing. After that, you should be able to reduce the amount of secondary air which raises the flame temperature. That in turn reduces CO and smoke. Triple win.

An additional way to handle it is to make two levels of air injection with 'holes' or fingers of air offset so they cover the circumference with the pattern, half each. This provides even more space between the air jets to encourage mixing but still covers the whole circumference.

Regards
Crispin

Paul,

Good catch.  That was supposed to be 7/64s, just shy of an 1/8 inch hole.

Yes, the secondary air enters under the cap below the holes.  I am sorry that thi was not clear.

Cheers,

Jock

Jock Gill
P. O. Box 3
Peacham, VT 05862

Cell: (617) 449-8111

Extract CO2 from the atmosphere!

On Sep 10, 2017, at 6:21 PM, Paul Anderson <psanders at ilstu.edu<mailto:psanders at ilstu.edu>> wrote:

Jock,

Seeking to understand your configuration.

1.  First photo says   Primary air holes @ 7/16ths.    Which would be almost 8 / 16th or almost 1/2 inch.   Does not look like the holes are that big.

2.  You do not have a concentrator hole.   Instead you have 2 concentric rows of holes (photo 2).   But does the secondary air enter UNDER the piece through a gap, or does the secondary air only meet the gases as the gases come out of the holes?

Looking forward to the video.

Paul

Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD
Email:  psanders at ilstu.edu<mailto:psanders at ilstu.edu>
Skype:   paultlud    Phone: +1-309-452-7072
Website:  www.drtlud.com<http://www.drtlud.com>

On 9/10/2017 4:36 PM, Jock Gill wrote:

<FullSizeRender.jpg>

Primary air holes @ 7/16ths

<FullSizeRender.jpg>

Vent holes.  Outer ring has 33 holes of 1/4 inch.  Inner rowing has 20 holes of 5/16ths.

The secondary air is pulled into the fire via the Venturi effect.  Hot gases rising pull in the cooler, but per-heated, secondary air that rise between the cap can and the reactor can.  Note: It appears that the diameter of the cap with vent holes divided by the diameter of the reactor can should be at least 1.6

<FullSizeRender.jpg>

The rector can can is about 6 inches in diameter.  It started life as a three pound Costco coffee can.

The cap sits on three angle brackets that create a gap of about 3 MM between the top of the reactor and the cap.  The secondary air enters through this 360 degree gap.  The cap extends about 2 CM down the sides of the reactor can.

The photo show the system as configured for my last test.  Achieved 1,000 F in the draft can on top.  Made some pretty good charcoal too.  450 grams of softwood pellets went for about 37:30.

The performance/results can be varied by the height of, or absence of, the draft can.  Also vent holes can be filled with bolts to reduce the draft.  Runs times can be extended to 50 minutes, but there will be quite a few pellets that are not charred or are only partially charred.  Longer run times have, not surprisingly, lower temperature yields.

A 20 second video to follow.  As you will see, this is not a completely smoke free set up at this stage of development.  Some tuning appears to be required.  Perhaps 1000 grams of fuel, as 450 grams leaves most of the reactor can empty.  More fuel will modify the draft forces.  Could be good or could be bad.

Thoughts?  Suggestions?

Cheers,

Jock

Jock Gill
P. O. Box 3
Peacham, VT 05862

Cell: (617) 449-8111

Extract CO2 from the atmosphere!

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20170911/00bbfe39/attachment.html>