Beesource Beekeeping Forums banner

Band heater vaporizer.

453K views 1K replies 124 participants last post by  johno 
#1 ·
I have been working on a 120 volt band heater vaporizer that can vaporize a hive through a 3/8" clearance hole at the back of the hive that has the hole plugged with a piece of 7/16" dowel until you need to vaporize. The first unit I made was temperature controlled with a mypin TA4-RNR and a type K thermocouple. The band heater was from Amazon, a110v-300w, 25mminternal diameter for about $8. Total cost about $50. I found pre heating for 5 minutes then inserting into the hive turning upside down putting on the cap with the 2 gram charge of OA then turning the unit the right side up vaporizing would take place in less than 1 minute. At this time a second cap could be loaded with OA to go again when the unit is moved to a new hive. So in theory after heating the device for 5 minutes a hive could be completed almost every minute thereafter. However I have found that when working in a yard with a cold breeze blowing this seems to rob some of the heat from the device and slow things down a little. I have also made a second vaporizer without the temp controller at a cost of little more than $10 and as I now know where the temp goes to I find the controller not necessary. I have used this in the yards from a battery and a $40 inverter and it works fine.
More info to follow as I progress with this project.
Johno
 
See less See more
2
#2 ·
To try to reduce heat loss to the device I have insulated the hot area with glass wool covered with woven glass tape and will try this out on a few hives later on this week. The vaporizer gets up to about 470F in 4 minutes when it normally took about 5 minutes, so it appears the insulation has increased the efficiency some. Measuring instrument Technology Electronic device

This high temperature does not seem to break down the OA as the particles can clearly be seen during test vaporizing also the temperature drops rapidly to around the 340F area while sublimation is taking place.
 
#4 ·
My starting point was the 25mm band heater so I had to go with 1" copper pipe which is about 1 3/16" or about 30mm which allowed me to open the band heater a little to allow for the 3/8"piece of pipe to protrude from the front. The band heater would probably be better closer to the bottom but then to find the right size band heater would be next. I could use the end cap plus a coupling to make up the chamber and still have the 1"pipe inside holding it all together, as the top caps I made from some 1" OD aluminum tube and they fit neatly into the 1" pipe and this helps seal the top. Also this was large enough to hold 2 to 3 grams of OA and the purpose was to do 1 hive at a time.
Johno
 
#5 ·
johno-
I've been following your progress on the forums. I purchased some Tempco band heaters (NHL00158) that are 1-1/4" and 250 watts (120v AC). They fit over the 1" copper pipe caps perfectly although the price is ~$25 each http://www.tempco.com/Catalog/Section 1-pdf/Mica Band.pdf
I'm going to try and use some silicon rubber corks on mine and see if they can withstand the heat. I've got some PID temperature contollers and thermocouples I'm playing around with also. I'm powering mine with a 750 watt inverter and a 22ah battery. I guess we'll see if the temperature contollers are necessary...
 
#7 ·
Hi Dynemd,
I hope the silicon corks work for you, will you be able to hollow them out so that you may be able to load the OA into them? This I think is the big advantage of the system, loading the OA into the hot container without any vapor escaping. Let us know how you progress.
Johno
 
#8 ·
Hi Crofter,
I would not mind if the heat source was closer to the bottom, as this is where the sublimation takes place and if the outlet pipe is not too high up and not too long the conductivity of the copper should keep it hot enough so as not to allow the OA to crystalize. As I mentioned one has to start somewhere and a cheap band heater is where I started. It has worked out OK as the 1" copper pipe and the 1" OD aluminum tubing made making the caps possible. The formica layer on the ply I used is standing up to the heat pretty well.
 
#9 ·
It looks like there are several manufacturers or stocking distributors for the band heaters in Que. Canada. I would say it is a much less involved construction than the tray types. Especially so if you can do without readouts or max temperature control.
It is a big plus to be able to vaporize without having to push something into the entrance of a colony and cover and uncover openings. The single tray type I am using is getting a bit of a pain to do a dozen hives a number of times for a series of treatments. It is getting a bit "old"!

I have reduced dwell times by dumping the charge into the tray while it is still hot enough to just start the initial fizzing but not yet much smoke. Do you have any reservations about how much you can push in this direction without compromising the effectiveness of the treatment. It really is hard to qualify the smoke, fog, vapor, or whatever it really is, solely by appearance.

Are you silver soldering or sil phosing the cap to the length of 1" copper?
 
#10 ·
Crofter, I have been using glow plug heated wands on my hives for a couple of years and it does become a pain removing entrance reducers to do the treatment frying a few bees while doing it and worrying if one of those fried might be the queen and then having to replace the entrance reducer when done. The last time I treated some hives I used a paper mask, one of those you get from your local hardware store and exposed myself to some of the vapor to see if it was as I suspected tiny crystals of OA as I observed while doing tests, result of that was not even a whiff of oxalic acid or even formic acid so I do not go along with the theory that high temperature in this type of system breaks down the OA. I think that the boiling and sublimation of the OA absorbs so much latent heat that it drags the temperature down to sublimation temperature. If the OAV was contained and did not escape that might be a different outcome. I used the silver copper alloy that most refrigeration folks use on copper to copper welding no flux is required.
Johno
 
#12 ·
Hi Dynemd,
I have oxy/acetylene so I had no problems, I do not know if you can get hot enough with map gas so it would be a pity to spend so much on the torch and find that you still can't do the job. Maybe someone on the forum would know if map gas can do copper to copper welding. I did a final OAV treatment on some of my out hives yesterday, put fondant on them and treated. I let the insulated unit pre heat for 5 minutes and loaded the OA and vaporized in 30 to 35 seconds, I noticed that when the OA hits the bottom of the vaporizer it flashes off and creates pressure in the vaporizer and blows the vapor out into the hive so the cap needs to be a good fit or vapor will leak out at the top. What I need to do in the spring is run a test on my 20 home hives and see if the vaporizer can maintain a high enough temperature over a longer period of vaporization. If it does not I will redo the unit using 2 band heaters.
Johno
 
#13 ·
I have done many joints with oxy acetylene but I doubt you could do that size with Mapp gas single bottle torch. The flame has to be large and soft not harsh (oxidizing) for either fluxed silver brazing alloy or self fluxing Sil Phos rod. If you spot overheat areas of the assembly, oxidation resulting prevents the alloy flowing into the joint. If you have to take it to a regular shop it will be too expensive. You will have to hook up with someone who has hobby gear set up at home or do it at work as a "government job".
 
#14 ·
I have just completed 3 of these band heaters using the 25 mm bands and 3 1/2" deep electrical boxes. The Mypin temperature controller fits the boxes nicely. A piece of conduit for the handle. The copper bowl and heater are mounted on a piece of phenolic. Less then $50 each. 40-370 degrees in 2.5 minutes. 2 grams of OA vaporize completely in 2.5 minutes (the outside temperature was 40 degrees, so this might be quicker if it were warmer}. 2.4 amps. 288 watts. I'll run 2 at a time from an inverter mounted in the truck and a heavy extension cord. I have 75 hives and have been using the wand vaporizers for several years. I'm thinking that the band heaters inserted through a 3/8" hole in the back of the bottom boards will be quicker to use and much more convenient. At least that's what I'm hoping. Thanks to Johno for the idea
. Technology Electronic device Cable Electronics Wire
Product Technology Electronic device Wire Electronics
 

Attachments

#15 ·
Indiankentuck, those look good. where did you get your band heaters, the ones I got from Amazon only draw about 1 amp. Still they preheat the copper to over 500F in 5 minutes and then will vaporize the 2 grams in 30-35 seconds, the temperature drops dramatically during the vaporization due to the latent heat being absorbed and if you look up into the plume of vapor if it is against the sunlight you can see the OA crystals glittering in the sunlight. So I am sure that the high temp does not break down the OA. I am not sure if the band heaters I have will maintain the 1 minute treatment cycle over a large amount of hives, I will check that out in the spring. The internal resistance of my heaters are about 145 ohms which is far too high for 300 watts at 120 volts.
Johno
 
#16 ·
I am going to test without thermostatic control or temperature readouts. The heaters I have on the way are nom. 300 watts. I have gone to the 30mm dia. which should be right on to fit on the external of the pipe cap and coupling sleeve.

If these get the vapor effectively into the hive without having to mess around with disturbing the hive it will make the treatments do able quicker and in almost any kind of weather.

Johno, let us know how the temperature stabilizes when multiple charges are put in and whether boil over and out the spout occurs. I have the option to make the barrel taller and place the second clamp heater on.

Have you done enough cycles to know whether recrystallizing in the spout is a problem with multiple back to back runs?
 
#17 ·
Crofter, in this last week I did a final treatment on some of my out hives with 4 hives per yard so I have not done enough trials. If I get a warm spell a little later in December I may give my 20 home hives another blast and that will tell a tale. If the unit cannot maintain enough heat maybe I could get one of the heaters Indiankentuck uses or else fit 2 of the Amazon ones onto the copper vaporizer.
Johno
 
#18 ·
I purchased these heaters from Ebay. $3 each and free shipping. The 25mm size fits a 3/4 cap perfectly with no gap.I think this increases the efficiency of the heater. Plus the phenolic isolates the bowl from any heat loss to the box. Without a temperature controller the temperature would be too hot very quickly. I am having no problems maintaining the temperature as vaporization occurs.
 
#19 ·
What I have in mind to try for a temperature control (if necessary) is a light dimmer switch. The are rated 600W if I remember correctly. I know a programmed setup would be more fool proof but this old fool feels left out if he doesn't have some knobs to twirl!;) Perhaps the setup will be near enough to self regulating that it will not need too much external control.

It would be terrific if the unit can be loaded with say 4 charges and will maintain a reasonable temperature till the charges are sublimated. I had not though that the latent heat of sublimating multiple OA charges would be enough to temperature stall the process but that will become apparent on test runs. I had a cheapie infrared temperature gun that would have been handy but it went for a crap.
 
#20 ·
I think that the higher temp creates a faster vaporization which increases the pressure inside the copper vessel and blows the vapor out into the hive, and by preheating I can get the 2 grams vaporized in 30-35 seconds with maybe 120watts, I did insulate the copper with fiberglass and that increased the efficiency some. I also have a gap of 2 nuts underneath the copper and then that onto a small piece of 1/4" fiberglass to insulate the heat from the aluminum bar the copper vessel is bolted to.
I think I will order a few of the band heaters from ebay and try them out. Crofter how is your heater working out can you measure the current draw at 120v or even from you 12v supply, even with the heater I have you can reach 500F in 5 minutes.
Johno
 
#21 ·
Johno, your band heater should draw more than 1 amp I'm sure. There are lots of places selling these things, I don't know if they all come from the same place in China. I agree that the higher the temp the faster the vaporization and the more pressure. There are those that argue that the OA turns to formic acid at temps above 370, but I have my doubts about that and probably will set it to a higher temp to speed the process.
 
#22 ·
Indiankentuck I checked my AC current with a clamp meter and it read very low so I put my multi meter in series with the heater on the 10 amp scale and it was close to 1 amp draw then checked the current draw through the inverter and found 11 amps also doing a resistance measurement on the heater which measured 149 ohms this all tells me the wattage is in the 120 watt range so I need to get some of the heaters from ebay. I also used a paper mask when I did some open air tests as I mentioned I could see the crystals glittering in the sun, never even got a whiff of oxalic acid and definitely no smell of formic acid which I am quite familiar with so I do not believe the OA is breaking down to FA.
Johno
 
#26 ·
Arnie-
It's a little complicated and the Mypin comes with chinese translated (not clear) instructions. Try taking a look here at this reseller, they have clear instructions. http://www.auberins.com/index.php?main_page=product_info&cPath=1&products_id=106
http://auberins.com/images/Manual/SYL-2362 instruction 1.6.pdf
You have to decide if you want 12 volts DC or 115 volts AC. How much amperage for your band heater, do you want to use an integral relay or a more robust external SSR (solid state relay) For a temperature sensor you'll need a thermocouple and a "K" type is the most common. Like this: http://www.auberins.com/index.php?main_page=product_info&cPath=20_3&products_id=144
 
#27 ·
Arnie, if you have a mypin TA 4 the wiring diagram is on the right hand side of the unit, and shows input 90-260V so black to #1 and white to #2 one of the wires from the band heater will also go to #1 a short piece of wire then connects #2 to #3 then the other wire from the band heater goes onto #4. Normal practices would have the relay breaking the hot leg but I have purposely chosen the neutral leg (white wire) so if there is a ground fault in the heater it will not destroy the mypin contacts. $Just make sure the unit is grounded. The thermocouples I got were type K and there were 2 for $7-70 , just remove the yellow plug and connect to#7 and#8 turn the unit on and if the temp does not start climbing in about 30 secs turn it off and reverse the thermocouple leads and try again.
Johno
 
Top