Hopper Liners

Discussion of hopper liners, moved from Carl Zinn’s thread.


A new kind of funnel, seems to be practical for assembling and deassembling!

Now, a question of deviation:

Why don’t you take the upper funnel up all the way cylindrically to the silo filling lid?
Do you think it would nullfy the circulation in the outer cooling tubes, through “competition” in cooling and lowering?

If the outlet for lowering gases is made as a “cowling grill” as in the 30-ies motor cowlings, the output of cooled gases would be great enough to avoid eighter circulation loop to “suffer”.

A cowling grill is of course needed in the upper end of the “cooling chimney” too.

A cylindrical cooling “negative chimney” will keep the silo content a little bit warmer, as the cooling downstream is separated from the wood mass.

I guess the down dropping tar and condensate will be easier to keep from recirculating, as it does not then slip down on the inside of the funnel down to the heath. Less wood smalls will go into the gutter.


I’m not sure what a “tall” funnel would do to circulation. Any covering of the tube openings would hinder it I think. I’m not sure if Terry L. still has the double wall hopper or not. I had a basket that went top to bottom all around. See here: http://driveonwood.com/comment/22355#comment-22355

It kept the wood 1/2" away from the wall to allow free circulation. I took it out with mixed emotions, because it reduced my fuel caring capacity by about 10% Also, my fuel is almost all kiln dried so there is not as much condensation as others might be dealing with. I even left off the top gutter to help reduce corrosion problems up there. These all sound like selfish concerns, and I know I’m not advancing the cause of water removal much, but that’s where I am for now.

Hi, Carl!

To clarify what i meant with “cowling grill”, here is a typical example:


If these louvers are tilted, say 20–30 degrees downward with the openings,

there is less of a risk to get wood-smalls into the gutter.

One louver-ring near the upper end, and another just above the gutter.

Additionally, you do not need any gutter “upstairs”, as the liquids are creeping down on the outer, cooler silo wall, well protected from interfering wood and heating gases.

1/2" gap to the silo wall may be enough to establish good downdrafts.

It is obvious, that outer cooling tubes will give the coolest return gas, but they are also needing delicate service.

The silo wall offers a cooling surface by it self, and the inner mantel insulates the woodmass from “direct” heat losses.


That is interesting. That is exactly what I did on my square hopper. Seems to work fine. My heat exchanger is on one side and the fuel liners with “cowling” are on three sides. The heat exchanger is between the hot drop box and the hopper. This adds some heat to the hopper to dry the wood while cooling the gas before exiting the drop box. So far I have not seen more than 350 degrees out of the drop box. That is surface temps because I don’t have a thermocouple in there yet

Good design on your hopper Don! I have a similar design, only longer slits, as Max mentioned.

Carl, Wayne, group,
Looks like you have similar incoming temps as the GEK(600C=1100F)

Good Morning fellows
Had to sleep on this one.
You fellows louver slitting an inner hopper liner have seen pictures of months in use hoppers? These pictures are historic 1940’s, 1970’s/80’s, to current daily users here on the DOW.
Seen the hopper crusts walls built ups?
Just how do you expect these louver circulation slots to stay clear of crust build up’s from clogging, eh?
This build up happens at every unavoidable from cold to warrming cycle. Then another layer added on cooling down closed up, misting depositing.
You are building yourselves an added chore to either hand “scrape-scrape” these slots opened back up. Or smoky torch burn off opened back up.
This is not a User practical solution. And never has been. IF you must do this at least like the Swedish SMP’s and Finnish VACOLA’s make this liner a pull-out for easier clearing cleaning.
And they only did this for restricted interstial flowing chips. Not for good interstitial flowing chunks.
edit s.u.
A far as WK hopper external cooling tubes cleaning . . . Wayne clearly is on his first generations usage concept proofing on this. Ha! And HE now always makes his hoppers as easy take-off’s! Power-washer blast these tubes clean!
2nd generation is already there in-use now with the fellows making these tubes as curved ended out of SS grab bar tubeing; or purpose formed larger diameter tubing. IF they upper gutter installed these as capable to flexible bore brush swab clear from the hopper inside, downward: then they are already at a 3rd generation capabilty.
If Not: 3rd Generation will be like all of the actual factory Imbert systems show on all of their tight cast 90’s with a brush accessible clean out plugs. They were over ten years real world usage “learned” by then. Go back and look at those pictures and now understand, Why the little side plugs!
WoodGas pipe plumbing 101: ALWAYS go BIG to account for buildups. And always have clean out ports!

Steve unruh

Hey Steve, Carl! So happens I was at hopper stage a month ago. . I found that a 30 gallon bbl nested nicely in a 55.gallon, lost a little hopper volume but worth it I think. Was corresponding with Max and he convinced me to louver - at least the bottom because top is not necessary as 30 gallon is shorter. Nice annulus between two bbls for cconvection and condensation. But it so happens this 30 gallon is removable as Steve suggests.

So somehow I misunderstood max and made my louvers a little differently. Used Ray Menke’s cool Miller plasma, cut C’s. Bent em in. Bigger opening so maybe longer before fouling

No, I haven’t seen the hopper crud build ups. Probably due to my separator lid. That will clog fast if I run out of wood and loose moisture.

Why are you quick to put cleaning louvers down when you also mention cleaning external hopper tubes? It is all woodgas, all dirty. We are slaves to cleaning maintenance.

I don’t find it gets that bad (crud wise) in our systems… and yes our inner hopper is removable… I don’t usually show much of this part of our system to people… unless you’re buying one :slight_smile:

outd is similar to what Max was talking about, just simplified a little…

Hey Terry,
Very well said…

“Why are you quick to put cleaning louvers down when you also mention cleaning external hopper tubes? It is all woodgas, all dirty. We are slaves to cleaning maintenance.”

For most of us, effectively removing moisture is very important.
There are more ways too skin a cat…
I believe Max was trying to show a method that will use less metal, labor and be serviceable… That works!
I’m busy telling Max what a good bunch people make up the DOW group, and when he pipes in with a suggestion this is what he gets.
How about focusing on improving… Rather than shooting something down?
Show a little respect. You are quickly losing mine.


Before Steve fires back, may I respectfully request that we honor Carl’s thread and take our “cat-skinning” (AKA arguing) somewhere else?

AT in TX

Well, I considered Steve U’s comments as a constructive learning experience and something to consider. I tried to move my original reply to my own thread shortly after I posted so as to not hijack Carl’s thread but it wouldn’t let me. Sorry Carl. I think we are done with this for now anyway. Back to you now Carl.

Edit: while I was writing this Chris made a new thread on Hoppers. Thanks Chris.

Moved to new thread, as noted above. Criticisms and opposing views are fine - just no personal attacks (haven’t been any here).

I’m a huge Steve U fan, he has helped me understand much . Same for Max. Like Don, I found Steves comments useful. We all have different experiences, different parameters, use different woods. Steve is from the rainforest, I’m from what is becoming a desert.
Different woods, different designs yield different results. All reported results, good and bad, are valuable data points that can help us understand more. Just like with Carl getting little tar, much corrosion and others getting more tar and less corrosion.

Probably many of us think, that Carl is most benefitted when he can contemplate and ask questions about proposals and ideas in his own time and interest.

When bringing up a construction example or idea, there is always a risk, that somebody is not aware of the results of using that solution in daily life.

The best way to learn about a new thing (questionable) is to ask questions about it and compare to known things.


OK guys saw this stack up of comments coming through on my E-mail echo.
VERY glad this has now been to a new topic directed. Thanks AdminChris.
edit s.u.
Don’t know now General Discussion, front side how to say much more without appearing to be argumentative or authoritative. I can’t even now point out how liners WILL kill external condenser tube flows without now WK system characteristics dissecting now into fine flows details.

The great thing about Internet woodgasing is it allows us ONE in less than 10,000,000 in the world actual woodgas DOers to connect up and and exchange.
The very BAD thing about Internet woodgasing exchanging it each of us lives in a different climate zones DEMANDING change adapting. With diffenrt fuel woods DEMANDING different change adapting. Then throw in wide spread diffenrces for woodgasing WHY YOU DO THIS into the mix.
edit s.u.
In the actual In-Use system Users get stymied by the much larger than pure simple clean molecular maths with the realities of air and fuels condensates, the thermal quenching effects of these, different soots in different areas, fuel base ash, ash melting points, ash thermal shielding (good AND Bad), clinkering and others.
A User can only Use-Experience thier way through these.
Sometimes that experience will take hundreds of system hours of real, loaded, In-Use to hammer them to realize ANOTHER Real problem to have to tear-down and rebuild/redesign for. Again. And Again.

Should be easy to see your system to really proof itself useable, must be year around seasonal adaptable. YOUR seasons. WHERE You live. On Your fuel woods So any idea, no matter how good it may seem it will not be dependable until you have at least one year proof-used it for ALL seasonal usage adaptability.

Drive On Wood mean not just garage pampering it for just public events.
Power On Wood for a generator set does not mean heated shop pampering it for Youtube videos, look-at-me’s.
Tractor On Wood does not mean just fine weather parade duty marching it out for smiles and waves.

Exactly three guys on the DOW have shown me vehicle hopper condensate removal systems that actual were removal effective: WanyeK, Vesa Mikkonen and Vesa Makinen.
I know this because they were getting 2X more condensate volumns out before hearth thermal dragging than after hearth thermal quenching, downstream in their coolers. They showed this in videos and pictures of their two different collectors sizing tanks. Different men with vastly different gasifer systems from each other. Different climate zones. Different vehicle useages. Different wood fuel bases.
That’s results Worked/Proofs.
Now take the WK very advanced 21st century external tubed condensing hopper “showing just as good results” as smooth sides hoppers. Put it on top of these other two fellow systems and it would FAIL miserably.
Beyond; they live in a climate zone where water is a solid for months of the year.
FAIL because the external cooling tubes are just the visible part of a whole internal refinery/distilling system that MUST have Mr Waynes not in the hopper thermal break upper hearth spacing waist “to not re-steam”. Not have his slit gapped fingered double flow “cones” (also not in the hopper) WITH the gaps acting as part of the internal distilling flows pathways!
This IS IMPORTANT. These three men have evoled BALANCED Needs SYSTEMS “packages”.
Gasification is not a “dream team” esoteric picking sport. In the real world your actual “team” loaded up with too many “Ideal” numbers/stats proven players and they will prima-donna fight for the limelight more than ever, team-play good. Then a team of inferiors like the 1980’s US Olympic hockey team will out team play and blow past them in results.
TWO things these “best-of” condneste removal systems do have in common is to NOT collect and then just let stored sit inside the gasifier the condensed out and guttered condensate!
Immediate gravity flow out to external remote reservoirs to cool and store.
Never, ever, put ANY back into the system like MENS and other styles.
Learn. Learn. These are the important devil details, overlooked.

Now on all weather, all seasons capable woodgasing generator duty I’ve only seen ONE system’s designers works that would not change to virtually unusable in a Febuary cold PNW 20 foot sideways drifting cold “rain”. Harsh? Yes. That is where North America 11,000,000 of us people actually live. Add in the other cloud rain forest regions of the world like NZ South Island, southern 1/3rd of South America, Northern Ireland, Iceland, Norway, southern greater Baltic area, Japan, 1/4 of China . . . well, see? NOT just SteveU. Half a billion people DO live just fine out in lots of annual months and months of predominate cold rain. Our equipments must also. Solutions for frankly Texas and Arizona and California areas just will not work

And I’ve only so far seen two modern tractor woodgas conversion being actually all season worked Proofed. The Swede’s Johan Liddel (sp) And Ron Lemlers in Indiana. AGAIN totally different continents, systems and fuels bases.
Proofs in seasonal flexibility use. Neither one of these fellows much bother by “idealizing”. Practical Working Rules in tractors.
edit s.u.
Past the talk . . . .

I have made myself to be a woodgas systems Operator expert. I can operate all kinds now in someway, to make IC piston engine run for a purpose. Even if this means hand beds loading. And lots and lots of duct/riggers tape, red silicone and furnace cement.
As an Operator I will be harshly critical of any designer/builder who limits me with “range use limiters”. Like a cyclone, a fixed grate, an only narrow velocity range capable hearth core; too small of gas flow piping. A system “beast” then that I must handcraft fuel for to be able to make it operate in some limited range fashon.
Pissed if I have to Fuss about a little rain or snow falling. Harshly critical a designer making me condnesate muck out through a clogging 1/2" hole - should be 1 1/2" minimum! Ash clean out through a 1 1/2 hole - should be 4" minimum. NO! I will not hopper “scrape-scrape” and holes unclog. Curved blade, long handle, single pass swipe-swipe up and down ONLY if needed. All of the time cursing the designer forcing this need. Make it operable WITH buildups!
I’ve had to torch burn off external soot flows clogging pre-heating tubes twice. Then Goodby to tube-air systems dumped for jacketed bang and tap soot clearing systems. Systems actual Operator NOT used (or not allowed feed-back improving) shows up in dumb-dumbs like these.

ALL my tools must be able to work under any conditions I am willing to work me.
And I work on through 15 of the 20 different kinds of regional “rain”. I work right down to the teens F. Happy it is NOT raining! The muck is frozen!
I work up to 100F. Ha! Then enough even for me. My tools must work this too or they get dumped, scrapped, shipped off for a more realistic wide range usable design. “Name” branding means nothing to me. Only proving sustaining performances.

Self-builds idealizing can get to where the system is Running You - not you; running the system!
Supply and sell to Users and they are not going to have your “burn-though-problems” idealistic dedication.

Go look at VesaM’s excellent “Gasifier Maintainances” video. Count the time. NO Hopper liner or hopper maintance steps. He desgns/build for woman users/operators.
DOW premium side go look at WayneK’s gasifer maintenance video. Count the steps. Count the time. Compare their collected wastes out. Very, very similar. Ha! Very few woman would do Waynes. He has some work there to do. Now, teenage kid operable proven.
edit s.u.
Fellows YOU design/build in lowest maintenance needs INTO your systems! This is not Not something that can be added/tacked on. Everything ADD-on NOT primary needed will drive up failures points and maintences then needed to avoid those failure points stoppages.

Most fellows will be years catching up to these two vastly different fellows in VesaM and WayneK… You can only shorten this by studying and focusing on the pertinent for YOU, and YOUR circumtances. And being a ruthless complications eliminator.

ChrisKY recently set aside his whole V-8 chunker system as complications added onto each other for a now 3-4 systems Users proven simpler, more direct method.
Ha! Ha! BenP just put up some V-8 “DeathsHead” chipper exposure video footage. See why that got hot potato dropped.
The OBJECT is to chunk-up wood. Period. Not now much noise, smoke and terror made doing it!
Be Objectively Goal driven. Get ruthless about this and you will advance for you and yours.

Steve Unruh

1 Like

Apologies maxgasman
Once I realized AdminChris had set this up as your named topic origination I went back up and changed my language from a North American short colloquial to as much of an International english as I can mange.
Some words left if they can be found in American and Brit on-line dictionaries.
Any use by me above with “you” means the group, not any individual, or you maxgasman.
THIS “you” usage for a collected group IS very American. Our rebellion still against the “English” imperial “We”.
Good joke that: “If you really must Weee please go outside, around the wall corner” ( the wind blows better there!)

I do not burden english as a second language members with such long SteveU “missives” (a ChrisKY new word for me).
Do you want me to delete this missive, above out? Just PM or E-mail me, yes. Or. Tell AdminChris and he will do this one-click for me.
Steve Unruh

My total being is to not be argumentative. I only asked the question to draw attention, not to take sides. To further our disscusion!

That said,

If someone’s hopper/cooling design is marginal, of course it will won’t pull as much moisture as it could with a more effective system. I don’t feel that a producer would fail because of a better condensation system. Steve, are you saying that Wayne’s hopper tubes will chill so much as to freeze the condensate in frigid conditions?
I, for one put my ride up once it gets below 20F. I have always called this my hobby, not afraid to state it!

Regarding hopper weather, I have found it quite benneficial here in Minnesota, to have an engine-hot-water heated hopper condensate reservoir. This is essential in winter. But in the brief summer the heat actually prevents the tar from separating (much) from the vinegar. So draining is improved year round.
I’ll spare y’all the photo of the very cruddy-but functioning hopper with a funnel-shaped liner just sloppy enough to let the condensate dribble down the vertical wall to the gutter. And I get a lot of vinegar to experiment with, too. I gave up draining the cooler in the summer: rarely more than a drop.

Hello all,

The videos below show soaking the wood in water before using it in the gasifier. I guess one could call this " gasifier abuse " but it will test the system . Maybe no one will report me to the humane society for making the gasifier eat this wet wood :wink:


1 Like