Small fan motors for wood stoves

Always good to have some helpful tips when making stove.
Where to get materials cheap, what tool is best.
How to do a specific task. Anything that will help.
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DarenN
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Location: Surrey, B.C. Canada

Re: Small fan motors for wood stoves

Post by DarenN » Mon Jan 05, 2009 8:47 pm

seudo_411 wrote:Hi all, I found a really good motor, the shaft is threaded, so i am going to make my own blade, So is there any one on the board who knows anything about, HVAC systems, or about air movement.
i do. :)
one idea would be to take a slightly larger fan and fit it to your motor. be sure to trim the blades evenly so that the fan stays balanced.
ask any questions you like. if i don't know the answer, i'll say so.

Daren.......
"I'd rather be happy than right." Slartibartfast

irrationalsolutions
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Re: Small fan motors for wood stoves

Post by irrationalsolutions » Mon Jan 05, 2009 10:44 pm

i dont know anything about these but how do you keep the heat from damaging the the fan blades and motor. the one i have seen have the fan mounted below the fire. i just want to know how you keep the burning stuff from falling on it. my thinking was that where the air can go up the little peices of burning coals can come down. i should be wrong since a fair number of people use these. can someone explain it to me?
“Do or do not... there is NO try.” Yoda

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zelph
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Re: Small fan motors for wood stoves

Post by zelph » Tue Jan 06, 2009 12:56 am

irrationalsolutions wrote:i dont know anything about these but how do you keep the heat from damaging the the fan blades and motor. the one i have seen have the fan mounted below the fire. i just want to know how you keep the burning stuff from falling on it. my thinking was that where the air can go up the little peices of burning coals can come down. i should be wrong since a fair number of people use these. can someone explain it to me?
Read this thread "Martha Stewart Stove" it shows how I added a small blower to the wood burning stove and all the rest on how it is made.
http://www.woodgaz-stove.com/

hoz
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Re: Small fan motors for wood stoves

Post by hoz » Tue Jan 06, 2009 8:06 am

irrationalsolutions wrote:i dont know anything about these but how do you keep the heat from damaging the the fan blades and motor. the one i have seen have the fan mounted below the fire. i just want to know how you keep the burning stuff from falling on it. my thinking was that where the air can go up the little peices of burning coals can come down. i should be wrong since a fair number of people use these. can someone explain it to me?
I made a small duct from some aluminum foil. The fan and battery sets about 6" from the fire pot. The foil folds up for packing and will last a few trips before it needs replacment.

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seudo_411
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Re: Small fan motors for wood stoves

Post by seudo_411 » Tue Jan 06, 2009 1:14 pm

Ok are you guys ready, Here are the specs for what i need to achieve, Firstly the entire blower assembly will have to fit in a 50mm x 70mm tube, The total diameter of the fan must be less than 50mm, now considering the fact that the motor has a 40mm long shaft, i would like to put two sets of blades on it, with a common shaft turning at the same speed, the idea is to gain some sort of compression. so i was thinking that blade one, being the primary intake blade, should have wider blades with less pitch and the second narrow blades with greater pitch. however the total surface area to pitch ratio of blade 1 must exceed that of blade 2, so that compression occurs.

I have gotten this far, here is the motor I'm gonna buy, http://www.rclines.co.za/index.php?main ... ge&pID=150

The questions I have are : is there a relationship between blade surface area, the pitch of the blade relative to the shaft, and the amount of air it can move.
From what i have read, the closer the blades are together the higher pressure you can gain. and the greater the surface area and pitch the greater amount of air can be moved. are there set formulas for these. or is all just a bit of testing. and lastly if i had a nice bowl of burning sticks being merrily stoked by the above blower, and i placed a piece of screen across it would it be better than if left open, I'm thinking MSR reactor....
Save space, Live on the edge...

Life might be a Bitch, but at least she knows who her Daddy is...

oops56
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Re: Small fan motors for wood stoves

Post by oops56 » Tue Jan 06, 2009 3:20 pm

seudo_411 wrote:Ok are you guys ready, Here are the specs for what i need to achieve, Firstly the entire blower assembly will have to fit in a 50mm x 70mm tube, The total diameter of the fan must be less than 50mm, now considering the fact that the motor has a 40mm long shaft, i would like to put two sets of blades on it, with a common shaft turning at the same speed, the idea is to gain some sort of compression. so i was thinking that blade one, being the primary intake blade, should have wider blades with less pitch and the second narrow blades with greater pitch. however the total surface area to pitch ratio of blade 1 must exceed that of blade 2, so that compression occurs.

I have gotten this far, here is the motor I'm gonna buy, http://www.rclines.co.za/index.php?main ... ge&pID=150

The questions I have are : is there a relationship between blade surface area, the pitch of the blade relative to the shaft, and the amount of air it can move.
From what i have read, the closer the blades are together the higher pressure you can gain. and the greater the surface area and pitch the greater amount of air can be moved. are there set formulas for these. or is all just a bit of testing. and lastly if i had a nice bowl of burning sticks being merrily stoked by the above blower, and i placed a piece of screen across it would it be better than if left open, I'm thinking MSR reactor....
Wow looks like a big motor to much air burn a hole in the stove and a very hi flame wast fuel a nice low flame better just touch all bottom of pot
Man play with fire man get burnt

oops56
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Joined: Wed Sep 19, 2007 11:31 am

Re: Small fan motors for wood stoves

Post by oops56 » Tue Jan 06, 2009 3:25 pm

Here is my idea on a fan.put a fan blade near the top let the up draft turn it to blow down see who wins :lol:
Man play with fire man get burnt

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seudo_411
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Re: Small fan motors for wood stoves

Post by seudo_411 » Tue Jan 06, 2009 4:11 pm

The idea is for it to ultimately become a wood gas stove, hence my wanting to put a metal mesh screen on top of it...
Save space, Live on the edge...

Life might be a Bitch, but at least she knows who her Daddy is...

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zelph
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Re: Small fan motors for wood stoves

Post by zelph » Tue Jan 06, 2009 7:11 pm

seudo_411 wrote:Ok are you guys ready, Here are the specs for what i need to achieve, Firstly the entire blower assembly will have to fit in a 50mm x 70mm tube, The total diameter of the fan must be less than 50mm, now considering the fact that the motor has a 40mm long shaft, i would like to put two sets of blades on it, with a common shaft turning at the same speed, the idea is to gain some sort of compression. so i was thinking that blade one, being the primary intake blade, should have wider blades with less pitch and the second narrow blades with greater pitch. however the total surface area to pitch ratio of blade 1 must exceed that of blade 2, so that compression occurs.

I have gotten this far, here is the motor I'm gonna buy, http://www.rclines.co.za/index.php?main ... ge&pID=150

The questions I have are : is there a relationship between blade surface area, the pitch of the blade relative to the shaft, and the amount of air it can move.
From what i have read, the closer the blades are together the higher pressure you can gain. and the greater the surface area and pitch the greater amount of air can be moved. are there set formulas for these. or is all just a bit of testing. and lastly if i had a nice bowl of burning sticks being merrily stoked by the above blower, and i placed a piece of screen across it would it be better than if left open, I'm thinking MSR reactor....
Why do you want compression to occur? It's not needed for a wood burner. Just a nice gentle breeze will do fine. Kick it up a notch and you can melt iron if you use coal.
http://www.woodgaz-stove.com/

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seudo_411
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Location: South Africa

Re: Small fan motors for wood stoves

Post by seudo_411 » Wed Jan 07, 2009 1:11 am

The reason i want to have slight pressure inside the stove is becose, I would like to place a piece of steel mesh, with 80 micron holes, So that i can prevent small embers from flying around. as well as for it to capture most of the heat that would normally be lost, next up is because the holes are so small I'm scared the fire won't draw properly. and as a bonus the mesh will act as a woodgas wick. I might also have a pot made, kinda like a jetboil kelly kettle hybrid, basically a 1 litre (or more) with say about 5 15mm chimney's that is just for heating water, and a 1.5 l pot for cooking. I'm thinking that i should build it to the jetboil, PCS and GCS, pot specs . Any suggestions on materials to use for the stove : doing a swat analysis on these metals. i.e weight, heat transfer, availiblity of material and tools, and lastly welding and cutting tools.

This is what i can get:
bright mild steel
mild steel
carbon steel
spring steel

Stainless steel
Aluminum stock and sheeting

and i'm still looking for either brass or copper.
Save space, Live on the edge...

Life might be a Bitch, but at least she knows who her Daddy is...

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