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Posted: Sun Nov 06, 2011 11:32 pm
by inonickname
Simplify the air motor... Small tesla turbine driving a fan. I'm sure your people could make on from scraps in short order.
Posted: Mon Nov 07, 2011 1:55 am
by D_Hall
inonickname wrote:Simplify the air motor... Small tesla turbine driving a fan. I'm sure your people could make on from scraps in short order.
Those go through craploads of air, don't they? I need to run the fan for about 72 hrs straight.
Posted: Mon Nov 07, 2011 4:33 am
by inonickname
Tesla turbines are fairly easy to make with high efficiency circa 70-95%, so driving a light load such as a fan wouldn't consume too much air if the turbine was kept small.
The only parts you have to contend with are bearings but I'm sure given your line of work that you could obtain 2 high temp bearings.
Posted: Mon Nov 07, 2011 5:31 am
by jrrdw
A defuser attached directly to the burner/heating element??? Is the oven all ready built? Can you install multible burners/elements?
Posted: Mon Nov 07, 2011 6:04 am
by Zeus
Does the oven need to be constructed of steel? You could set up the fan drive like a hot plate/magnetic stirrer, having magnets drive the fan without contact.
Posted: Mon Nov 07, 2011 10:58 am
by Technician1002
Can you use a fully enclosed motor either water or air cooled, or does the motor have to be at the oven temperature? An air cooled fully enclosed motor with an insulating blanket may do the job if the motor needs to be enclosed in the oven. Another option is an enclosed motor with a water jacket and thermal blanket.
Posted: Mon Nov 07, 2011 8:43 pm
by D_Hall
jrrdw wrote:A defuser attached directly to the burner/heating element??? Is the oven all ready built? Can you install multible burners/elements?
Not sure what you mean with the defuser comment.
Oven isn't built. Yes, it will include multiple elements.
Zeus wrote:Does the oven need to be constructed of steel?
No, but the fan needs to be at the top of it so I'm not sure how you'd do it with a simple magnetic link.
Technician1002 wrote:Can you use a fully enclosed motor either water or air cooled, or does the motor have to be at the oven temperature? An air cooled fully enclosed motor with an insulating blanket may do the job if the motor needs to be enclosed in the oven. Another option is an enclosed motor with a water jacket and thermal blanket.
Nothing prohibits a jacket, but ease of manufacture is important. The fan is going to run for 3 days and then quite literally be blown up. Cost is important (and labor is a cost).
Posted: Mon Nov 07, 2011 9:08 pm
by POLAND_SPUD
The fan will be used to stir air in an oven, but the oven will be destroyed before all is said and done.
D_hall Y U no use an
oven fan ?
http://www.ebay.com/itm/EBM-FAN-MF11-OV ... 2eb494650d
Posted: Mon Nov 07, 2011 9:25 pm
by D_Hall
Looks great!
But ebay is a non-starter.
1) It's illegal for the gov't to purchase used items.
2) I need a steady supply of 'em (ebay sucks for that).
Beyond that, I do thank you for the link. I've been googling and not finding a suitable model. At least that one looks appropriate (PERFECT, actually). Now I just need to track down a steady source of new....
Posted: Mon Nov 07, 2011 9:38 pm
by POLAND_SPUD
wait that's not a real oven fan... I tracked down that part - it's used in some big encloseres called ovens - definatelly they don't have anything to do with heating stuff... infact they are used for cooling
real oven fans look more like this:
http://allegro.pl/silnik-termoobiegu-am ... 73056.html
Posted: Mon Nov 07, 2011 9:48 pm
by D_Hall
POLAND_SPUD wrote:wait that's not a real oven fan... I tracked down that part - it's used in some big encloseres called ovens - definatelly they don't have anything to do with heating stuff... infact they are used for cooling
LOL... Yeah, I was just coming to report that the max operating temperature for that fan turns out to be 75 C.... Just a bit shy of my needs.
As for their ovens... Probably epoxy curing ovens.
Posted: Mon Nov 07, 2011 9:56 pm
by dewey-1
Posted: Mon Nov 07, 2011 10:26 pm
by POLAND_SPUD
I've found some info on fans used in smoke removal systems but I can't find even one part (well apart from dozens of pages on alibaba.com but that isn't very useful)...
either they aren't really that popular or I am not using the right term
OR
http://en.wikipedia.org/wiki/Kearny_Air_Pump
&
http://www.clippard.com/store/byo_cylin ... -08-4-|||V
&
solenoid valve + 555timer/time relay
naah but seriously you can buy clippard air cylinders which are rated to 200F
add to that the fact that the only thing that will get damaged is the air cylinder that seems like a pretty good deal (@~30$ per air cylinder)
Possible fan
Posted: Mon Nov 07, 2011 11:50 pm
by Technician1002
A possible fan source may be the fan used on convection ovens, either commercial or residential. It may be the motor is outside and at a lower temperature than the air temp it circulates.
http://www.blodgett.com/Literature/Part ... -parts.pdf
Posted: Tue Nov 08, 2011 1:02 am
by Hotwired
$75 looks fairly low to have a new fan for that temp.
How feasible would it be to improvise a propellor/impellor on a shaft which exits the oven to be chain/belt driven by an external motor.
That way the motor could be isolated from the heat even over 72h and the air stirring assembly won't break the bank, depending on how much time technicians can spare for the fiddling needed to build it.
Might not even need to be belt/chain driven if the driving shaft between motor/fan can lose enough heat to not upset the motor.
The fan itself I'm imagining could be sourced as a steel truck or car radiator fan.