Tall Homemade Cabinet Style Incubator Heat/Fan Question

[Three Cedars Silkies]

I placed a piece of sheet metal just below the heat source that protects the eggs that are approx. 12 inches below. With the lower wattage bottom heat source added, the temperature is perfect throughout.

I chose to use bulbs instead of a heating element because of the plastic interior of the wine cooler.

 

[shelleyd2008]

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I have a question about this if you don't mind. Most designs show the fan blowing across the water source for humidity. Where would you put the water in an incubator with a false back like this?

 

[_Randall_]

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I have a question about this if you don't mind. Most designs show the fan blowing across the water source for humidity. Where would you put the water in an incubator with a false back like this?

Use the same concept as GQF. I'm in the midst of building a cabinet bator, and I will have a false back (~5" in from the main back all the way from the top of the bator inside to 7" from the bottom. (Bator is 24" deep x 22" wide x 32" tall). My water shelf will come out from the false back 12" deep. My fans will be mounted to the false back (between the false back and main back....blowing out across the water pan). My heating element is the one GQF uses, and will be mounted on the activity side of the false back. I plan to post some pics soon. My philosophy of going almost to the bottom with the false back is when the fans are blowing across the heating element and water, that warm damp air will have to travel "downward" acoss all the eggs (no matter how many racks you have as long as the opening is below you bottom rack) before it "returns backward and then back upward for a continious flow. The fan and element in the pic below is mounted to a "very short" false back. It stops at the water shelf. Now, picture that false back going "almost" to the bottom. The moving air is circulating, and will have to go almost to the bottom to make the trip back up between the false back and main back to make the trip again, thus creating circular flow, thus even temp.

 

[muddstopper]

I pretty much agree with Randall, except I dont think a 7" gap at the bottom is necessary. In one of the pics I posted, you can see the gap at the bottom I used is only about 1" tall. . The interior space between my false back wall and the exterior back wall is only enought to clear the fan and other componets. Since I do have a small hole drilled in the back so the fan can pull in some fresh air, my air flow is designed to give a slight pressurization to the egg tray area. I dont have anything to measure this pressure and know it cant be very much, but I want the warm air to stay with the eggs for a slight moment instead of just blowing right by them. Anyways, I designed my gap sizes to match the cubic inches of the fans diameter to create constant movement of air circulation, it only thru the fresh air vent hole to the exterior of the cabinet that the fan is able to create a positive pressure inside the egg tray area.

My water pan is also located directly infront of my heat source and works just fine for me, but I have seen some homemade incubators that place the water pan at the bottom of the incubator. It should work in either position, but consider you already need a top shelf to seperate and direct the airflow from the fan and heater, why increase the size of the incubator to accomidate a water tray at the bottom when you already have a perfectly good spot at the top.

 

[_Randall_]

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Mudstopper, the only reason I'm leaving that much gap on the bottom of the false back is because I've got a 120v receptacle mounted in the bottom left hand corner of the main back (mounted horizontally), and that gap gives me access to plug in my two egg turners. I may shorten the gap though, based on your theory.

Question though.............I'm putting a hole in the main back right at the level of the fans to pull in fresh air like you did. Do you have any other holes in the bottom of the back or sides for "exhaust" - or - "flow through" for fresh air balance, or are you satisfied with the "positive pressure" with just the the intake hole(s) at the back of the fans?

 

[muddstopper]

Since i have noway of measureing the pressure inside my incubator, I am only assuming that I do have positive pressure. My air vent is just a 1/4in hole drilled in the exterior side panel of the incubator, about level with the fan location, and inbetween the false wall and the back exterior wall. I dont know if it makes any difference if the hole is drilled where I did it, or if it would be better to place it directly behind the fan. It is where it is in my incubator because that is the spot I had intended to bring in the power cord. I changed my mind about the power cord location and had the hole to deal with. Since I needed a fresh air vent, I left the hole open. Since I think I do have some positive pressure, I can assume that I have air leakage around the front door to let some air excape, this is what would create the fresh air exchange. A lot of guessing and assuming on my part since I have no way of measureing the exchange or air pressure, but since my eggs hatch, I can only guess that my guesses are correct.

You didnot say what kind of turning trays you where going to be using, but since you will be plugging and unplugging the individual trays, i am assuming you will be using the plastic turning trays like go in the small styrofoam incubators. If this is the case, why does the electrical connection need to be at the back of the cabinet, why not mount it close to the front where access is easier, maybe even plugging in at the top instead of the bottom. I cant visualize what you are trying to do with the electrical connection, so maybe my suggestion wont work. If you go to a electronics supply store, you should be able to find smaller electrical connetions than a house type plug receptical. I'm thing a small surge protector with enough outlets for ever how many trays you plan on using?????

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I know every kind of thermostat is going to work a little differently, but I prefer to have my thermostat mounted above the top shelf where air from off the heat strip can blow across it. That might be the way Rebel is decribing it, but his wording sort of has me confused. My reasoning for this is I want the air blowing down toward my eggs to be pretty close to the 99.5 degrees I incubate my eggs at. Air that has to return up thru the the backside of the false wall is going to be slightly cooler than the air entering the tray area. A Temp reading in the return air area will probably be lower than what would be measured at the egg trays. I guess either method would work as long as you are using a seperate thermometer to monitor the actual temp in the tray area. The area above my tray area, where the heater and fan are mounted, I call my heat reservoir and I try to monitor the heat there so that it is around 100*-100.5* at all times. I check this from time to time with a infared thermometer, I didnt design it this way, its just the way it worked out. I really only need to know this information incase I decide at some point to try a digital readout thermostat and want to fine tune the settings. As long as the temp in the tray area remains around 99.5*, it doesnt really matter what the temp is in the heat reservoir

 

[_Randall_]

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They are the LG turners. I chose to put this at the lower left back out of the way, since it's a plug-in-and-forget-it for most of the incubating process. The power lead pigtail feeding this receptacle will have a plug itself. However, I'll have a control box with 4 switches on the side. One for the heater (which will have a digital thermostat in the circuit), one for the inside lights, and one for each of the (2) cabinet fans. I'm putting two cabinet fans in there...........either run both if needed, or one as a backup if the other one goes out.

 

[SED]

OK, how about a false back with a fan at the top to force air down over the heat source and a fan at the bottom to circulate the air. Water at the bottom and the top go help get humidity where it needs to be. What about something like this?

 

[rebelcowboysnb]

That would work but you can mount the top fan just like the bottom one an that would let the back section be smaller. May not need 2 fans anyway. You also wont need two things of water so you could lose ether one an make more room for another turner or to make it shorter.

If you did make the back section that big you could put bread pans in the bottom back there as you water pans an fit more turners up front.

 

[muddstopper]

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I think i would reverse the air flow from what you have drawn. I also suspect that with two fans the one in the path of the air off of the heat source might get a little to hot. Really, all you need is one fan, I circulate my cabinet air with a 60cfm fan. The objective is to keep the air moving inside the cabinet, not create a breeze. I also agree with Rebel, take out one of the water trays and add another egg tray