Homemade Bit Stoker?

Homemade Bit Stoker?

PostBy: unhippy On: Mon Oct 21, 2013 6:30 am

Has anyone here homebuilt a subBituminous coal stoker?....I'm in the early stages of building my own, and i'm looking for any rules of thumb or the likes that would help in the design...especially how on much air it will need....I'm in New Zealand so getting to have a look at a home heating sized one to shamlessly plagiarize isn't an option so i'm having to pick up ideas off youtube and this forum....

currently i have built a base for the stoker to mount into and the boiler to sit on, have material for the boiler but haven't started it yet, it will be vertical firetube with 16 2 inch tubes with chain turbulators the full length of the tubes, will be hydro tested to 35psi

i have a 4.75" screw/auger and a old 5" hydraulic cylinder barrel with a 5", long-radius weld bend on the end, on top of which my tuyere will be attached...still have to build the air shroud for under the tuyere

Tuyere will be 5" I.D at the bottom with straight sides up to a 1/2" radius out to 6" at the top and will be about 5" deep and is based on a picture of a fines coal stoker tuyere off Kotly.com...lol and they are even nice enough to put up a scale drawing which gives me a rough idea of the air hole centers, sizes and configuration
i know 5" isn't very big but i don't need much more than 30 to 40 thousand BTU

The drive motor/gearbox is a 1/3hp 1440rpm motor with a 60:1 reduction box (still waiting on the gearbox to arrive) that will have a cam and arm setup driving a 1/2" ratchet, with a snap-on 5 deg ratchet it should give me about 1/3 of a turn per minute so i may need to put a belt reduction on the output of the gearbox to the cam arm if it is too fast ....i liked how the EFM ratchet worked and bush engineered it with stuff i can get hold of (this is all built apart from the having the gearbox mounted)

the fan is driven off the rear end of the auger drive motor and is a cage blower that replaces the cooling fan on the motor with the intake being a shroud that pulls air the full length of the motor fins to keep the motor cool...the fan outlet is piped to the air shroud under the tuyere with a gate valve to dump excess air and in doing so control the air pressure under the tuyere (this is still at sketch stage but all material is on hand to build)

Flue will be of 6 inch but haven't got that far yet

My coal hopper is a open top 44 gallon drum with a sealing lid, the bottom will be cut out and a 30deg cone will be installed and feed into the auger( i have the drum but nothing has been cut as yet)

the coal i will be running is 8500btu subBituminous with a zero swell index and in my coal range(cookstove) you have to try damned hard to get a clinker out of it, the ash is a fine powder like some hardwoods produce

control gear will probably consist of a wood boiler draught regulator actuating a magnetic switch to control the stoker on/off...i can't get aquastats etc suitable for boilers here....and the ones from the US don't do so well on 240v 50hz...
i have an over temp control valve that opens at 95C and will dump cold water thru a cooling loop of copper tube in the top of the boiler before going down the drain, it closes when the boiler temp has dropped to 89C

still have to get the pump,pex,manifolds, plate HX for DHW,and thermal balancing valve for control of DHW, from overseas but i have the radiators locally...salvaged from a school that was pulled down

So...anyone see any truck sized holes in my boiler setup?
Cheers
Callum
unhippy
 
Stove/Furnace Make: Homemade
Stove/Furnace Model: MK1

Re: Homemade Bit Stoker?

PostBy: franco b On: Mon Oct 21, 2013 12:01 pm

Good for you and good luck.

You are building what amounts to a prototype so the more you can do interim testing and tweaking the better.
franco b
 
Hand Fed Coal Stove: V ermont Castings 2310, Franco Belge 262
Baseburners & Antiques: Glenwood Modern Oak 114
Coal Size/Type: nut and pea

Re: Homemade Bit Stoker?

PostBy: unhippy On: Tue Oct 22, 2013 3:28 am

yep building a prototype and needing to have it work in fairly short order is pretty par for course for me...lol its my job as well so i always make things so that each sub assembly can be removed for alteration without having to pull things apart too much.

i built (in a hurry due to a sudden change in location) an automated waste oil boiler a few years back that worked out pretty well so doing a coal boiler seems like the next step.

i think i have all the obvious pit falls covered but time will tell
unhippy
 
Stove/Furnace Make: Homemade
Stove/Furnace Model: MK1


Re: Homemade Bit Stoker?

PostBy: Lightning On: Tue Oct 22, 2013 5:20 am

Please post pictures as you make progress partner. I'd be interested to see how it all goes together :D
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash

Re: Homemade Bit Stoker?

PostBy: Duengeon master On: Tue Oct 22, 2013 3:52 pm

Lightning wrote:Please post pictures as you make progress partner. I'd be interested to see how it all goes together :D

Yeah, Pictures please!!!!
Duengeon master
 
Hand Fed Coal Stove: Harmon Mark III
Coal Size/Type: Anthracite pea and nut mix. Bituminous lump

Re: Homemade Bit Stoker?

PostBy: Sting On: Tue Oct 22, 2013 4:39 pm

Only one I see is if the tweeteres are not cast iron they will fail very quickly if made out of mild steel

but

It Depends!
Sting
 
Other Heating: BurnHAM=NG-gas

Re: Homemade Bit Stoker?

PostBy: Berlin On: Tue Oct 22, 2013 6:40 pm

I made tuyeres out of jet-turbine blades from a gen set. They're inconel, they already have holes (nat. gas holes) and if finessed, they will work as good or better than cast iron.
Berlin
 
Hot Air Coal Stoker Furnace: Will-Burt Combustioneer 77B
Coal Size/Type: Ohio BITUMINOUS pea stoker coal

Re: Homemade Bit Stoker?

PostBy: carlherrnstein On: Tue Oct 22, 2013 6:48 pm

Inconel :shock: that stuff is unpleasant to work.
carlherrnstein
 
Hot Air Coal Stoker Stove: combustioneer model 77B
Coal Size/Type: pea stoker/Ohio bituminous

Re: Homemade Bit Stoker?

PostBy: Scottscoaled On: Tue Oct 22, 2013 8:10 pm

You can't get Honeywell single Aquastats? 4006A's or 4006B's They work fine with 240V.
Scottscoaled
 
Stoker Coal Boiler: EFM 520x4, 350, 700. Van Wert 400 x 2, 800, 1200.
Coal Size/Type: Lots of buck

Re: Homemade Bit Stoker?

PostBy: unhippy On: Wed Oct 23, 2013 4:36 am

Sting wrote:Only one I see is if the tweeteres are not cast iron they will fail very quickly if made out of mild steel

but

It Depends!


i should have mentioned it will be cast iron
i have a 8 inch diameter round of cast iron 6" long on its way to me

Scottscoaled wrote:You can't get Honeywell single Aquastats? 4006A's or 4006B's They work fine with 240V.


Not that i know of locally.....New Zealand has never had much in the way of boilers for home heating so there is no market for things like that.

i might have to try get one in from the states if they will work alright on 240V
unhippy
 
Stove/Furnace Make: Homemade
Stove/Furnace Model: MK1

Re: Homemade Bit Stoker?

PostBy: Sting On: Wed Oct 23, 2013 8:26 am

all you need to control a 240 circuit is switch one leg - so these will function just fine
Sting
 
Other Heating: BurnHAM=NG-gas

Re: Homemade Bit Stoker?

PostBy: agcowvet On: Wed Dec 18, 2013 9:38 pm

Old thread I know. But sounds interesting, not much call for it right around now, maybe closer to fall eh.

Best confirm w/ Honeywell, before paying for shipping, on aquastat suitability. Sting--their 240v circuits aren't like ours, there isn't a grounded neutral and 2-120v legs, it's just straight 240 for everything. Makes for much faster electric kettles and more powerful portable electric radiators.

Spent best half year of working life there five years ago, down in Southland, mainly getting calves out of cows, among other things. Smell of soft coal burning still reminds me of coming into town (worked out of Gore and Tapanui, lived in Mataura.) Good luck sounds like an interesting project. Might try a commercial supply house or service company, hydronic stuff seemed to be more common in public buildings around where I was; houses were either electric (air-source minisplits or resistance) or coal fireplace/stove (which I'm sure you know Callum, more for other folks here.)
agcowvet
 
Hot Air Coal Stoker Furnace: efm AF150
Hand Fed Coal Stove: Hitzer 50-93
Other Heating: Newmac NL-2 (oil)

Re: Homemade Bit Stoker?

PostBy: unhippy On: Thu Dec 19, 2013 6:03 am

agcowvet wrote:Old thread I know. But sounds interesting, not much call for it right around now, maybe closer to fall eh.

Best confirm w/ Honeywell, before paying for shipping, on aquastat suitability. Sting--their 240v circuits aren't like ours, there isn't a grounded neutral and 2-120v legs, it's just straight 240 for everything. Makes for much faster electric kettles and more powerful portable electric radiators.

Spent best half year of working life there five years ago, down in Southland, mainly getting calves out of cows, among other things. Smell of soft coal burning still reminds me of coming into town (worked out of Gore and Tapanui, lived in Mataura.) Good luck sounds like an interesting project. Might try a commercial supply house or service company, hydronic stuff seemed to be more common in public buildings around where I was; houses were either electric (air-source minisplits or resistance) or coal fireplace/stove (which I'm sure you know Callum, more for other folks here.)


hi agcowvet.... you where down a bit to the south of me...i'm in Dunedin....Gore and Tapanui etc were some of my teen stomping grounds....lol you wouldn't believe the increase in the numbers of dairy herds round there....its pretty much on the way to trebleing since you were here.

i have confirmed that the honeywell aquastats aren't really able to be used here....found an electrician that has dealt with them here in a school heating system.....seems the higher voltage arcs the contacts and things like that.....he said that they work ok if you pull them apart every 3 to 4 months and file the contacts like in an old points dizzy.

Plans have slightly changed, boiler is on back burners for now due to my GF loseing her job....the boiler i can make....the valves, pipes and pumps etc i have to buy....and thats not happening on one income that makes ends meet if you stretch it really thin....boiler system construction will be resumed once she finds a new job

So for next winter i am building a stoker stove....3 inch screw feeding into a machined cast iron 4 inch tuyre all mounted in/on a salvaged wood stove.....can be controled with a standard thermostat that i was given (its amazing what people will throw out because it doesn't match the light switches).

Will post pic's once its more than a pile of parts waiting to be butchered
unhippy
 
Stove/Furnace Make: Homemade
Stove/Furnace Model: MK1

Re: Homemade Bit Stoker?

PostBy: Sting On: Thu Dec 19, 2013 9:24 am

good catch
I missed the New World location :oops:
Sting
 
Other Heating: BurnHAM=NG-gas

Re: Homemade Bit Stoker?

PostBy: Duengeon master On: Fri Dec 20, 2013 8:43 pm

unhippy wrote:
Sting wrote:Only one I see is if the tweeteres are not cast iron they will fail very quickly if made out of mild steel

but

It Depends!


i should have mentioned it will be cast iron
i have a 8 inch diameter round of cast iron 6" long on its way to me

Scottscoaled wrote:You can't get Honeywell single Aquastats? 4006A's or 4006B's They work fine with 240V.


Not that i know of locally.....New Zealand has never had much in the way of boilers for home heating so there is no market for things like that.

i might have to try get one in from the states if they will work alright on 240V
Sir, you mentioned earlier you have 240v 50hz in New Zealand. Here we have 240v 60hz. It probably won't work so don't order one from the States!!!
Duengeon master
 
Hand Fed Coal Stove: Harmon Mark III
Coal Size/Type: Anthracite pea and nut mix. Bituminous lump