Reverse engineering Riley pellet burner

[gooch]

I decided to make a clarry to see if it was much different in producing heat. The clarry is hands down a better stove. There was a little more in the fabrication but the heat it puts out is phenomenal and it uses less pellets. Here are a couple of pics. First is fabrication then in use.

[rectifier]

Neat, I have not burned my stove in awhile due to a month of warm temperatures (no heat needed in December? is this Canada?). But it has cooled down and it is time to get back to testing.

I suspect the main reason your Clarry is much hotter is due to the greatly superior heat exchanger, I remember when I first coupled my Riley-style burner to a box stove like yours, most of the flame went up the chimney. The Clarry bends force more heat loss. Just looking at the pic of those stoves next to each other, in the Riley, the flame will shoot straight out of the burner into the 6" stack - the Clarry has 2 bends and a 3" stack, so a long flame scrape over the lower channel and lower exhaust velocity. Does it burn clean or does it give off light particulate?

I think I will try coupling my Riley burner to a u-bend like that sometime. The rocket barrel has great flame velocity and heat recovery, but is hard to start when the stack is cold. That Clarry bend should start much more reliably. Also it is much lighter to pack and slimmer to carry in a truck/use in your shack.

Would love to see more pics of your Clarry burner internals and any data you have on extended burn times!

[gooch]

I should be heading out to the shack this afternoon and will take some more pics. The box part of the Riley has a large baffle that forces the air back on itself before it went up the stack. It was the 4" that went into the bigger stove. The 3" went into my smaller camp stove with the 3" stack as shown in my first set of pics. I thought that by increasing the stack size it would increase the draw. The 4" definitely ran hotter than the 3" but would only get the box hot enough to cook eggs. The actual 4" Riley section got plenty hot and that's why I decided to try the Clarry. I'll try to get my friends heat detector and see if I can get some readings. I took the Riley and box out of the shack and lowered the Clarry to get more heat down lower. There is no insulation in my shack. It was -30 and I was in a t-shirt so it definitely works. We also cooked sausages in a cast iron pan in no time. I think you could attach the Riley to a "C" shaped unit and get a lot more heat out of it. You would need to have an ash pan at the first angle to catch the ash. The Clarry also seems to burn cleaner and results in less ash. It uses less pellets also. I ran it for 6 hours the other day with no problems and didn't have to give it a bump every once in a while which was nice and didn't distract from the fishing. I will get pics of the internals but you can see them in my fabrication pics. The burn grate came as a 12"x16" piece that cost $5. All in the material was $60. I have enough grate left over to make at least 1 more should this one ever burn out. They didn't have any heavier material for the grate but you could always drill holes in some 1/8". At least it wasn't too difficult to bend. I did add a small piece as a diverter and grate stop in the upper part of the lower section where the pellets drop in, and YES it lights much easier as well. I have not had any blow back even in high winds.

[gooch]

OK, here are the pics of the internals. Not much to it. There is a burn grate and an ash pan. Here are a couple shots inside the ice shack and cooking up some sausages. This thing is awesome!! I scaled it down to 3x3 with 2x3. My shack is 4x6 and uninsulated but at -25 and the holes open in the floor it can get pretty chilly but this size does the trick. It looks like their smallest is a 4x4 and largest may be a 5x5.

[rectifier]

Wow that is pretty sharp! The Clarry really is very simple in construction and looks like it worked right away for you as opposed to all the tuning I have done with the Riley. Looks awesome for tents or for ice shack, how much radiant heat does it throw off or is it mostly convective?
Does it have a throttle control of any sort or does it run at a constant power? Obviously gets pretty hot to cook those sausages!

Low power seems to be a weakness of the Riley stoves, mine throws immense heat at high power into a RMH downdraft heat exchanger. You just can't run them into a box stove or there is no efficiency, they require a tortuous path to extract the heat. As you mentioned the Clarry C shape may work, I am planning another Riley stove with a C to try it out.

Now that it got cold, with the rocket barrel and an aluminum flex stack with a fan on it, we are heating my shop (>5000sqft) to 15C with 3/4 bag a day, outside temperature -10C. The entire 4" firebox glows cherry red, the rocket barrel hits 1000F, and you can hear the rumble of flame turbulence from 30 feet away. As you can see I am concerned the Clarry grating would rapidly degrade at these power levels, whereas the thick steel of the Riley internals has taken a thrashing for months of daily use without any significant degradation.

I am planning a highly modified carburator which is still in the design phase (too busy for fabricating) that may be capable of long burn times at lower power.

Anyways, our applications are very different but it looks like we both have a great stove that we are happy with! I kind of want to build a Clarry just for fun now!

[stork]

I'm still around tinkering with the burnner ... I tried your test and I'm suffering from the pellet jamming , must say tho " VERY Impressive!!!!" ( first shot at a rocket stove)..... think I will try square tube instead of the round feed tube entering the top of the burnner , that might free the pellet flow some ....
My app is for a wall tent (60 -0 F temp range) , so I would like to be able to use wood if'n the pellets run out before we're ready to pull out ...
like most of the gassifier type stuff I've built , this burns real hot, clean and produces unreal heat ... Got me thinking to run the burnner into a rocket then thru the stove ,(have to raise the stove up some) , and see what happens ...
as far as the grate worries on the Clarry use stainless for the burnner grate ... play with the hole size .. start small and work your way up (easy to make bigger , no fun to make smaller..LOL) ...stainless does work harden , so spray with a water bottle , don't get any blue chips if your drilling with a hand drill...

@ jackvegas they make stainless steel sheet metal & pop rivets(tho pricey compared to steel), might be the way to fly after you get a good working proto type built .... I really like to see you get this going for the guys that don't have or have the acess to the big buck tools .. I'm spoiled rotten with a good home and hobbie machine shop in the back yard ...

after writing and posting this i suddenly noticed there's 3 more pages on your thread ... You've been busy !!!! Great info and reshearch !!!!

A question for gooch ... what is the proper name for the shut off gate you have on your feed tube ? I haven't been able to find one at the local HomeDump or Lowest .... Just try to ask them ... " if they don't have it ,It doesn't exist" they'll tell ya ... LOL ... time to find one online .... 30 yrs ago any mom & pop hardware store could tell you where to get one if they didn't have one on the shelf collecting dust ...

Managed to scrounge some 6" & 8" well casing scraps form a old driller buddy last nite ... I think it might make a good rocket tube for the burner to go in up to the stove port....

[gooch]

It's called a shut off (blast gate) for a dust extraction system. Picked it up at a hardware store.

[scbron]

I have been looking at the various gravity feed pellet stoves and I think the Clarry looks better than the Riley. the ash removal is separated from the burn plate, so it can be cleaned without having to let the fire go out.

Also, I dont think the grate will burn out. Heat rises and air will be entering through the grate which will keep it cooler. Stainless would be a good option.

I am a blacksmith and have made forges out of mild steel. The conventional wisdom was that only cast would hold up to the heat but this did not prove to be true. the steel is under the fire where it is coldest and the forges made out of 1/2" steel and a 2000 degree fire held up just fine.

Has anyone made progress on their experiments, I am ready to build one soon. It is getting cold.

Thanks for all of your work.

[gooch]

After building both as I said earlier in this post the clarry is a far superior unit and does not require any additional heat chambers

[jackvegas]

Thought those interested in the Riley and Clarrey feed systems would also be interested in this gravity feed natural draft pellet stove that I recently ran across.

Web site for company is:
wisewaypelletstoves.com/

Full description of stove is in US patent # 7861707

Attachments:

[johnmaster]

So does the much simpler Clarry design work as intended? I want to burn wood chips (dried if necessary) and I am looking for a design to get started. I am building a rocket mass water heater and looking for a natural draft natural feed solution if possible. This is going to be an outdoor "open to atmosphere" boiler for heating both home and shop. Without plans it looks harder to mimic the Riley. Trying to get it right early on as I won't have the comfort of a heated are to test and tun this thing. Thoughts?

[imaddicted2u]

Came across this thread and it got me wondering about using a Riley burner inserted into my old coal boiler to heat my house. I use an oil fired boiler for heat now but the coal boiler is still in the heating circuit. Looks like at one time there was an oil burner added through the door of the coal boiler. There is a plate on the door that could be modded to accept a pellet burner.
Is the Riley burner safe enough to use indoors. Any other ideas?

[mechartnik]

build an experimental feed unit to play with outdoors, once you understand it .... lots of people are wondering the same question: @ retrofitting an existing unit, myself included: use EXTREME caution is the best I can suggest to this point.

I added some mass/constriction to thw exit of my inefficient woodburning add on furnace: but replacement/redesign is the best option in my mind, either go RMH or very efficient high radiant heat output is my current approach...

spend some (alot of) time reading before you try modifying your current, indoor, setup.aka

andor

[jimpeltier]

very nice.i have been searching for the spec on a clarry stove but cannot find demensions.i have a 8 x 16 foot ice shak and would like to heat with pellet stove.what i would like to know is what size tubing you used and length.thank you

[joseph]

Nov 16, 2011 17:27:42 GMT -8 rectifier said:

Took it for a spin on sawdust today. Started on a hopper full of pellets, gasification mode was established after half an hour and 1/4 hopper of pellets were burnt. After 3/4 of the hopper had been consumed, I stuffed it full of sawdust, a mix of coarse and fine.

The remaining 1/4 hopper of pellets were completely consumed. At that point, the first of the sawdust to ignite formed a charcoal bridge that didn't break, the feed stalled and it went out.
So...
- sawdust too light? it is less than half the density of pellets. Maybe even a quarter. Light and fluffy.
- sawdust too wet? it had been kicking around the shop in a pail for a year, the shop is near 100% humidity much of the year
- not enough air to the bridge area? There is only air attacking one side as the other was welded better. Going to grind it out anyways.

Those were most likely the issues. I don't plan on looking into it much as I would need a huge hopper to make it through a day with the low density available. It's much easier to use a controlled fuel like wood pellets - or perhaps 1/2" or smaller wood chips? My goal is not really heating my shop, it's heating a hunting tent/cabin, and I'm not bringing sawdust into the woods.
....

Other than this one time two years ago, has anyone tried running this type of stove on coarse sawdust?