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  1. #81
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    Default Re: Talk About Your Incubator

    AstroBee. Very common thinking. First of all in a chamber as small as a typical queen cell incubator the temperature at the cells will be nearly identical as that at the heat source. But lets assume that you are correct and that there will be a difference at the cells hang their is at the heat source. The more accurate way to control this is to have the heat sensor at the heat source since that is what it is controlling and a thermometer at the cells. If you set the controller to 95 degrees but the thermometer reds 90 degrees at the cells. simply increase the temp the controller is set at.

    Keep in mind no thermometer sensor or controller is goign to achieve the proper temperature. None are reliable. I never have just one thermometer and I only use thermometers that agree in their reading when set side by side. So do not think you can set a temperature controller to 95 degrees and then think you will in fact get 95 degrees. You have to measure it for accuracy.

    SO why is it better to have the sensor at the heat source/ Because if you move the sensor away from it the heat has to build up until it reaches the sensor. this will cause the air near the heat source to actually be over heated. Remember it is energy in energy out. and you end up over energizing parts of the incubator. This over energized air will spread across the incubator and cause a temperature spike. as the air cools it will also tend to fall below the correct temperature more also. this is because there is more of a recovery necessary when the sensor is further from the heat source. the entire chamber has started to cool off and the heat source cannot catch up quite quickly enough. this may or may not be a problem depending on you specific design. There is also a period when you first start up an incubator that it will over heat then under cool . but each time it cycles it will be over or under by fewer degrees. it is something like a pendulum swinging back and forth. but let it set for a while and it will stabilize. If you still have a swing in temperature ti will become very close to equal above and below the set temperature. Once you see that you have seen just how accurately your design can hold a set temperature. Shorter more frequent bursts from the heat source produce a more stable temperature than a longer but less frequent one.

    You can place your temperature sensor any place you prefer. but I do recommend you try different locations and take careful measurements so that you are aware of what happens with the various placements. In my case the swing in temperature of having the heat source just 6 inches from the thermostat was enough to kill Serama embryos. Queen cells are not nearly as delicate. In my 4 cubic foot incubator I place the thermostat 1 inch from the heat source for very tight temp control. in my 22 cubic foot incubator it is 3 feet away. Exact temp in the big one is of little concern. In my queen cell incubator I actually place it just about anywhere and then set the temp according to thermometers placed right on top of the cell cages.

    If temp swing is not a problem the n none of these measures are necessary. but when swing is a problem it can be frustrating to get figured out. So I added this info for those that may need it.
    Stand for what you believe, even if you stand alone.

  2. #82
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    Default Re: Talk About Your Incubator

    Adding a small fan (like those used to ventilate computer cases), positioned where it pulls air from the heat source, and blows it over the temperature sensor, can be a major help to reduce the response time of the thermostat, reduce temperature swings (pendulum effect), and reduce variations in temperature and humidity throughout the incubator.
    48 years - 50 hives - TF
    Joseph Clemens -- Website Under Constructioni

  3. #83
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    Default Re: Talk About Your Incubator

    Quote Originally Posted by Daniel Y View Post
    Keep in mind no thermometer sensor or controller is goign to achieve the proper temperature. None are reliable.
    That is a mighty broad statement. Don't you mean none of them that you have tried?

    Quote Originally Posted by Daniel Y View Post
    SO why is it better to have the sensor at the heat source/ Because if you move the sensor away from it the heat has to build up until it reaches the sensor. this will cause the air near the heat source to actually be over heated. Remember it is energy in energy out. and you end up over energizing parts of the incubator. This over energized air will spread across the incubator and cause a temperature spike. as the air cools it will also tend to fall below the correct temperature more also.
    I'm pretty sure your reasoning is faulty there. I suspect that you are correct in that precision is possibly not as critical as one might think, but as the saying goes "aim small, miss small." You can often successfully analyze a system by considering the extreme cases - the place you are really concerned about the temperature is indeed at the cells. Which is where you should be measuring it. If the cell was 10 feet away from the heat source you aren't likely to get good results taking the temp at the heater, but you might with the thermostat probe at the cell - if the heater was enough to heat the required volume. If this caused a temp spike when the heater cuts off, then it would anyway no matter where the probe is. The location of the measurement has nothing to do with that.

    You are correct in this as well - you are more likely to get good results if the incubator is in a climate controlled house instead of an unheated shed. The extreme case being that you would get even better results if you could keep the house thermostat turned up to near the target temp so that the incubator heater rarely ever had to even come on. Better results as far as keeping the temp even - who knows if it matters to the developing queens?

    If you had enough thermal mass inside the incubator, and enough insulation around it, and it was in an environment that was maintained at or near the target temp then once it was all up to temp and the heater went off it would never need to come back on for the entire duration - and your heat source could be a Christmas tree light. In which case if it did cycle on any attendant spike would be tiny because the heat source is so small. That might not be practical (then again it might) but it tells you the direction you would need to go to get better consistency.

    If it matters that is.

    Not trying to start a food fight, we're just talking here.
    Since '09-25H-T-Z6b

  4. #84
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    Default Re: Talk About Your Incubator

    David, All I can say is build them and test them. Anything is possible "If" but lets see you build an incubator with a heat source from a Christmas tree light. I am not supposing here. my comments come from actual building and testing of incubators. Some of them tested multiple times over 21 day periods logging temperature changes to a tenth of a degree. These incubators needed to maintain temperatures between 99.3 and 99.7 degrees for 21 days. I built several of them.

    In reality you would have no concerned about temperature spikes from an incubator powered by a Christmas tree light. it would never get to temperature.

    You are correct in that you will get an accurte rading of the temp at the cells by placing the probe at the cells. what you will not get is accurate heat control at the cells by placing the probe at the cells. you get accurate heat control by placing the probe at the source of the heat. Lets say the surface of the heating element is 500 degrees and this temperature declines quickly as the distance from this surface lengthens. and in the first few seconds after the element is turned on the air just one inch from the surface is only 100 degrees. at two inches the heat can barely be felt. But over time that element heats a larger and larger mass of air. until after 30 seconds of burning the temperature up to 100 degrees now expands 3 inches from eh surface of the bulb and the temperature of the air 1 inch away is now 300 degrees. After one minute the air up to one inch from the surface is nearly that of the surface itself air up to 3 inches from the surface is now 300 degrees and the 100 degrees mass of air extends 6 inches from the bulb. You cells and probe are 10 inches from the surface. By the time that 100 degree air reaches the ells and the probe and turns the element off. There will be a ball of overheated air that is still traveling toward the cells. and it is to late to stop it. The heating part of the cycle has just started when our probe decides to say stop. And the temperature is not goign to stop rising at those cells just because your probe finally measured the correct temperature. In realty you will very likely watch your temperature at the cells reach 95 degrees the heat source will turn off and you will then continue to watch the temperature rise to around 103 or so degrees depending on just how you built your incubator.

    I am to sure that it makes sine how I am trying to describe it. In my mind I picture it as a wave of over heated air and the further the probe is form the heat source. the larger you allow that wave to get. Placing the probe close to the heat source produces smaller but frequent waves of the proper temperature.
    Stand for what you believe, even if you stand alone.

  5. #85
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    Default Re: Talk About Your Incubator

    Daniel,

    I appreciate what you're saying - not sure I agree with everything, but if it works for you then great.

    I do believe that if you have a heating element with low thermal mass (light bulbs for example) and forced air circulation (I feel this is a key design feature) then temp overshoots will be basically zero. I know that they are in my system as I outlined earlier. FWIW, the Ranco controller is very reliable and reasonably priced.

    Here's a good example of a chicken incubator. BTW, he's controlling the temp at the eggs.

    http://www.youtube.com/watch?v=1DxCW3JU8KE
    Horseshoe Point Honey -- http://localvahoney.com/

  6. #86
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    Default Re: Talk About Your Incubator

    I am extremely familiar with both thermostatic controls and heat sources...I've used them both all of my life.

    I don't give a rip what the temp is at the source, only at the point where the heat is being used.
    Monitoring and controlling it there mitigates a host of variables.

    Monitoring at the the heat sources often results in depowering the source prematurely, and taking much longer to reach temperature at point of use.

    That's why a home thermostat is in the living room or hallway, and not next to the burner in the furnace or boiler.

  7. #87
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    Default Re: Talk About Your Incubator

    Quote Originally Posted by Daniel Y View Post
    David, All I can say is build them and test them. Anything is possible "If" but lets see you build an incubator with a heat source from a Christmas tree light.
    Fair enough - after all talk IS cheap. So I whipped together a quick demonstration to see...



    I didn't have an actual Christmas tree light on hand - so that is a night light bulb in a utility socket with an candle base adapter. The box is a styrofoam shipping container that refrigerated medical supplies like insulin come in (My wife is a nurse and I am a packrat) there are two bricks in there for thermal mass. As you can see there is about 1 3/4" of styrofoam insulation lined with aluminum foil.

    I heated the bricks in hot tap water to get them pre-warmed.



    I set it up and let the temp stabilize for a few minutes before recording the temp 107 F at 1:50 PM Then let the whole thing cool off for several hours (with the light turned off) until 9:00 when the temp was 86 F. Then I plugged in the light. 15 minutes later it had heated to 95 F - so clearly that tiny little bulb is big enough to warm it up - in my rather chilly garage BTW. Then I unplugged it and watched the thermometer - no measurable increase in temp. I went through several cycles to make sure turning it off at 95 and on at 94. No temp spikes.

    No this isn't exactly an incubator since it doesn't have a temp controller so I guess it doesn't prove that much... Actually it kind of does - use a smaller heat source and put some thermal mass in there and you won't have a problem with temp spikes.

    Anyway now I pretty much have the bug.
    Since '09-25H-T-Z6b

  8. #88
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    Default Re: Talk About Your Incubator

    Well done sir.
    Solomon Parker, Parker Farms, ParkerFarms.biz
    11 Years Treatment-Free, ~25 Colony Baseline

  9. #89
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    Default Re: Talk About Your Incubator

    Thank you.
    Since '09-25H-T-Z6b

  10. #90
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    Default Re: Talk About Your Incubator

    It occurred to me how quick and easy it would be to do the control part of the experiment. So I went out and changed to a 60 watt bulb and took out the bricks. The thermometer said 73 when I plugged it in - when it hit 95 about 90 seconds later I turned it off. Sure enough the temp continued to climb to 99 before it stopped.
    Since '09-25H-T-Z6b

  11. #91
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    Default Re: Talk About Your Incubator

    Wow that's quite nice! With such a gentle heat source as a Christmas tree lamp you could probably install some cheapo temperature controller & it would work well.

    An incubator that would even be doable for a small beekeeper who does not want to spend much money!

    Nice work!
    44 years, been commercial, outfits up to 4000 hives, now 120 hives and 200 nucs as a hobby, selling bees. T (mostly).

  12. #92
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    Default Re: Talk About Your Incubator

    Different type of Christmas tree bulb than I was thinking of. but that is due to an old conversation and not due to this one. Watt is the wattage of that bulb? It looks like the container is a monster for holding the heat. My incubator for queen cells is also a medical container. just much larger than this one. 2 inch thick foam. The main measurement I am seeing in this is 15 minutes to raise the temp 9 degrees. How far from the bulb is the probe?

    The main thing I see is an incubator that is seriously under powered. You going to be okay with your cells setting around in there for 15 minutes waiting for the incubator to even get to 95 degrees? dropping to 86 for an incubator that is already up to temp may be a bit much. mine will fall to 90 if I take to long putting things in and out. Still that is around 7 minutes or so for it to recover. I would like to see that in less than 1 minute.

    I can't even set mine up and take comparison measurements because my temp controller is operating my kiln right now.

    Would be interesting to see how this preforms with a controller.

    Oops I did not see your human controller post before sending this. now set it up with one thermometer probe at the queen cell location. and one near the bulb. control according to the probe near the bulb. and see if the temp at the queen cells stay more stable.
    Stand for what you believe, even if you stand alone.

  13. #93
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    Default Re: Talk About Your Incubator

    For those that are into large scale production of queens and really serious about top notch control. A free standing independent incubator is probably the least cost effective way to go about it.

    First of all you are going to be talking about incubators that are closer to the size of a refrigerator. Energy use is going to start becoming worth paying attention to. and the larger the kiln the more the control effects show up. The way I have seen large scale done. is the room the incubator is also temperature, humidity and even light controlled. They also have positive air pressure with the incoming air filtered. Keep in mind this is as state of the art as it gets. So when you open an incubator you get no temperature or humidity change because the room itself is at that temp and humidity. Because the incubator is inside an incubator you can power them extremely low and not have spikes. In fact they seldom come on at all. You can in this case just go with the room being the incubator and forget the smaller ones. But for as near perfect control as I have ever seen an incubator inside an incubator is the way I have seen it done. I have seen these environments run none stop around the clock for years and never waver. Keep in mind that the rooms in this case are like walk in refrigerators. insulated to the teeth, sound proof, thick walls, secure sealed doors. they are not playing around. These animals are used for medical research and nothing about them can be altered. They are as near identical clones of each other as can be produced. They also happen to be about as sickly as you can get. they could not survive outside of that environment for even a few hours. In large that is due to genetics and breeding. but some of it has to do with the environment they where produced in in the first place. This is why I question stable being better. If you want a strong queen full of vitality you may have to treat her a little rough to get her there.
    Stand for what you believe, even if you stand alone.

  14. #94
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    Default Re: Talk About Your Incubator

    I took the "guts" out of a cheap styrofoam incubator I bought at a farm store and mounted the heat source in a deep drip pan under hardware cloth attached to a 10 frame deep which I lined with 1/4" to 1/2" foam. It holds up to about 600 cells at a time. I monitor the temps with an electronic probe and it holds a constant temp with less than a degree variation though it needs to be kept in a room temperature area. For humidity just a damp rag resaturated daily. I use it on a daily basis for about 2 months a year. I use a simple power inverter to power it when carrying it to the beeyards. I like using the same frames that are used in the builder to eliminate handling and to keep them vertical. You can go bigger and more sophisticated but I really don't see what you gain. Hives no doubt fluctuate more in temperature than my incubator. Btw I really like David's idea of the bricks for thermal mass particularly if it gets left unplugged or in a cool area for any length of time.
    "People will generally accept facts as truth only if the facts agree with what they already believe."- Andy Rooney

  15. #95
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    Default Re: Talk About Your Incubator

    A bottle or two of water would be a more effective thermal mass. Water has a much higher heat capacity than brick.
    Solomon Parker, Parker Farms, ParkerFarms.biz
    11 Years Treatment-Free, ~25 Colony Baseline

  16. #96
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    Default Re: Talk About Your Incubator

    Quote Originally Posted by Solomon Parker View Post
    A bottle or two of water would be a more effective thermal mass. Water has a much higher heat capacity than brick.
    Good point. When installing cells on cool mornings I like to "zap" a couple of heat packs wrapped with towels. We carry them in the incubator until needed. We put the heat packs in a small foam soft sided cooler to lay the cells on top of. Its probably overkill but it sure does make me feel better installing them even though they have only been out of the incubator for less than 10 minutes.
    "People will generally accept facts as truth only if the facts agree with what they already believe."- Andy Rooney

  17. #97
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    Default Re: Talk About Your Incubator

    OK, Daniel - I know that you have worked out a system that works for you to your satisfaction. Marvelous. I'm not trying to change your mind on that. Your theories about what produces better queens - I neither confirm nor deny them - I have no data, and therefore no opinion.

    The point of my impromptu experiment is that some people are observing temperature fluctuations in their setup and want to even them out - I understand that you are not in this camp.

    I threw this together with what I had on hand - it is not intended to be an actual incubator, and if it was it would only be able to accommodate a few cells at a time.

    The main take away is this - the higher the wattage of your heat source the harder it will be to manage temperature spikes - more insulation just lets you use a smaller heat source. Secondarily the more thermal mass there is inside of the system the more stable the temp will be once it is warmed up and stabilized. In my opinion a heat source which is just enough to maintain the target temp is not under powered - it is well engineered. Feel free to use a blow torch though if you want to.

    Notice that it took 7 hours for the temp to drop 21 degrees with no heat source at all - about 20 minutes per degree F. The reason that it took 15 minutes to warm it back up in my test is that the thermal mass was at 86 degrees instead of 95. Once the bricks were stabilized at the correct temp the residual heat from them alone would probably almost bring the system temp back up after opening the lid for manipulations.
    Since '09-25H-T-Z6b

  18. #98
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    Default Re: Talk About Your Incubator

    Quote Originally Posted by Solomon Parker View Post
    A bottle or two of water would be a more effective thermal mass. Water has a much higher heat capacity than brick.
    I didn't know that - although I use 55 gal drums full of water in our winter "plant room" as thermal mass and it works great. Solar gain during the day and residual heat from the water at night keep it moderate enough to maintain house plant for all but the coldest part of the winter with no additional heat at all. Same principle.

    Quote Originally Posted by jim lyon View Post
    I took the "guts" out of a cheap styrofoam incubator I bought at a farm store and mounted the heat source in a deep drip pan under hardware cloth attached to a 10 frame deep which I lined with 1/4" to 1/2" foam..
    Clearly a cell incubator which can accommodate standard frames is the way to go - this thing is just what I had on hand. I still think I might make one out of the beemax Styrofoam supers that I don't much like in the apiary. So, do your cells actually ride around in a truck during incubation? According to most reports they are really fragile at that time. Of course it wouldn't be the first time that the conventional wisdom was less than accurate though.
    Since '09-25H-T-Z6b

  19. #99
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    Default Re: Talk About Your Incubator

    My mentor and another of his mentees are trying an egg incubator, and are having problems with temperature swings. They're seeing peak temperatures around 106 F and dips into the high 80's. They asked if I know anything about PID controllers.

    I know a little. Only been working with them for about 30 years. Now back when I was a boy, we bought PID controllers for $500, and we LOVED it!

    I've got a couple of ongoing projects for which I bought a pair of modern Watlow controllers, but while looking for those I noticed that e-bay is flooded with an inexpensive (frequently under $20) model called the REX-C100. You can get them either with relay output or set up to drive a solid state relay. I picked a relay output model up for $18 from a US seller, and it arrived in 2 days. For a heating element, rather than a light bulb I intend to try a $15 Sunbeam heating pad (12 x 15 inches, 50 W). Considering the high humidity, the heating pad may be better.

    I routinely use type K thermocouples for temperature measurement and control. That's the standard sense element on the REX-C100s. Mine, like most being sold on e-bay, came with a thermocouple. Be sure to check.

    PID controllers can "run away." Electronic malfunctions, bad settings, and relay failures can set them full on. Some form of backup control should be used for safety. I'm going to test the heating pad to see if it does that by itself, but otherwise there are 120 V thermostats designed to run with baseboard electric heaters that are an option. You can also buy electronic backup controls, but if the failure were caused by a big spike, I prefer the KISS approach.

    PID controllers typically auto-tune, so they learn to minimize temperature excursions and can hold a very even temperature. They're not entirely smart, though, and will git a bit ditzy if left running while the incubator door is open.

    I'll keep you guys informed as to how this goes.

  20. #100
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    Jan 2014
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    Default Re: Talk About Your Incubator

    Sheesh, this result is so off I have to wonder if I know how to calculate this stuff.

    I rigged up the little REX-C100 with a 50 W Sunbeam heating pad (18 x 12 inches). We stuck the heater and control thermocouple into a Coleman cooler with interior dimensions of about 14 x 13 x 19 inches. The interior is not exactly a cube but I'll approximate it as 9.49 square feet. I used a small circulating fan and the heating pad was spaced off the bottom with a piece of radiant heat floor aluminum spreader plate, with air circulating under it. I monitored two points in the cooler with a good Omega thermocouple thermometer.

    Running almost full on in a 77 F room, the heater could just manage about 91.4 F. That's a temperature differential of 14.4 F.

    An online converter says 50 Watts is 170.6 BTU/Hr. Cranking the other numbers in, the heat flow was 1.25 BTU/(Hr-Ft^2-F), and R value is the reciprocal, about 0.8. That's in US units. I was expecting an number more like 5 or 7. 0.8 is a value I would expect from a 3/4 inch thick pine box.

    Are Coleman coolers really that bad? Sheesh!

    We're building our own box, probably with R11 insulation. We'll lose some to ventilation and a double-glazed viewing window, but it still should not be that bad.

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