homemade incubator question-new question* update with pics

[rebelcowboysnb]

Moving air is not actually colder than still air so if it is colder at the fan its because cold air is being introduced to the incubator at the fan.

 

[kvmommy]

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Ahhhh...ok. I'm gonna try something then. When the kids are asleep, I'll post pics! I'm kinda proud.

 

[aprophet]

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If you blow the fan at the top of the bator it will wash the hot air down the walls of the bator and pull the cooler air upward this constant mixing of air is what you are looking for the heater and the thermostat will cause the temp to stay at where you set I have a remote bulb thermometer that lays right on top of the eggs and I can watch the temp float down to 99.2 and the t-stat turns the light bulbs on then it goes up to 100.4 or so and cuts back off the fan constantly circulating the air

 

[Clay Valley Farmer]

LOL if anything set up like the factories do the thermsiphoning effect is increased with a fan LOL

What I was saying is that the fan is so any more times powerfull than a thermosiphon that the thermosiphon effect becomes meaningless.

Thermosiphon exists only because warmer air expands becomes less dense and floats upward on top of the cooler more dense air. If you have a fan in the incubator cool and warm air is constantly mixed to the same temperature any thermosiphon effect within the incubator will be lost. True from top to bottom inside to outside there will be an effect, but thermosiphon is a very week effect on the small scale. If air enters the incubator from the bottom at 70f degrees and leaves the top at 99f the air will have changed density from 0.0745 lb/ft3 to 0.0706 lb/ft3.

Assuming the height from bottom vent hole is 1 foot and the foot print of 1 ft3 of air 1 foot in height is 144 in2 the pressure differential will be 0.000027 psi, enough to make air move? Certainly, but not fast. Adding a chiminey to the outlet of a still air incubator would help draw air as it would effictivly make the height from inlet to outlet greater creating a greater pressure differential.

Small computer fans on the other hand are rated at about 2mm H2O which is about 0.0029 psi and over 100 times greater than the thermosiphon effect.​

 

[fishman65]

you do NOT need insulation...the thickness of the wood has a great R-rating....The incubator my friend has (GQF i think) has wood sides and NO INSULATION.

 

[Clay Valley Farmer]

Sure you don't need insulation, you could just put the eggs 3 feet infront of a 1500 watt space heater... Guess we don't need to insulate houses either...

It's just that if you do add insulation you can make the incubator more efficient and the conditions in it more stable.

 

[aprophet]

Quote:
and they work well

LOL

 

[kvmommy]

Here's pics of the bator!!

top view with lid up.

top view with lid down

front view with easy access door shut

front view with easy access door open

another view from top

It was toy box that opened from the top. I cut out the picture and put hinges on it for a door. There are two 40w candleabra bulbs attached to a reptitemp thermostat...theres a flex watt heat tape in there thats not hooked up. IT just didn't cut it. The turner is an adjustable window screen with 1 in. pvc pipes glued to it with a dowel through the whole thing. I rotate the dowel to turn the eggs from side to side.