I've been thinking about the same thing. Forget the battery/inverter; that heat gun would drain it very quickly.

I am concerned with dosage, but I have seen comments that it could be very high without damage.

What capacity container? I am thinking a funnel shape to keep it feeding. The design will need to hold the crystals, but release the gas, so a fine screen on the bottom section. It needs to be made with a non-reactive material.

 

Next the biggest challenge, identifying the housing used for the oa. I've done some searching, and with some previous conversation, it looks like it could be a water meter housing.

Looks like the housing for a water meter to me too.

http://www.kids-and-science.de/uploads/pics/Fotolia_5635362_XS.jpg

The heat gun used in the video is a very expensive unit, top of the range and top quality. At our local hardware store it costs over 120 euros.
Why not use a gas burner instead, couple that to the water meter housing and then you have a portable unit that's much faster to set up and use.

a simple gas vaporizer can be seen here. https://youtu.be/apiIe_QQSv4

 

The problem with any heating method is control and ensuring it isn't overheated and burned instead of sublimated. Those have way different chemical results. Maybe some sort of thermostat control would be in order, but that will add cost and complexity.

Another problem I've noticed with the external tube / burner process is making sure it doesn't recrystallize in the tube before it gets to the hive. The fan in the heat gun should ensure it stays sufficiently hot long enough to be delivered into the hive and circulated.

How hot is "too hot" for internal hive temperatures? It may need something like venturi tubes to cool the flow with outside air.

 

By blowing the OAV into the hive rather than allowing it to filter through the hive Via convection you risk uneven concentration. While at the same time increasing the risk of exposure outside the hive. Such a device although workable would not provide consistency. overheated oxalic acid can be a bad thing, while under heated can be ineffective. I have treated my hives with A conventional vaporizer for over 5 years, I treat over 100 hives per treatment. By using 2 Vaporizers. I can do one and while I leave the hive closed up for 10 minutes. I set up the other and activate the vaporizer. by the time I get the second hive sealed up and activated the first hive is done, I take that unit and move it to the next hive. I have several apiaries the biggest one has 50 some odd hives and Is 30 miles away, I can treat is in a day with no rushing or stress. all the others combined in another day. A third unit would allow me to do more hives in less time. and additional units would to a point expedite the process. The true beauty of this system is if one unit malfunctions it does not put me out of business until I can fix or replace it. It simply slow things down a bit. I have used one unit for 5 years and it is still going strong, making it's cost per treatment pennies. Sometimes developing an effective method of using the equipment available is better than trying to build a better mouse trap. IMHO

 

By blowing the OAV into the hive rather than allowing it to filter through the hive Via convection you risk uneven concentration.

Luckily the Bees fanning distributes the OAV throughout the hive, you can see this in action if you leave the entrance or the crown board open a little. The vapor is expelled in pulses as the hive breathes (bees fanning).

Sometimes developing an effective method of using the equipment available is better than trying to build a better mouse trap. IMHO

I think your right.

A simple design is always the best and complicating or adding unnecessary features just leads to more failure points. I think the original idea of copying a product that works well is the way to go, reducing trial and error ie time wasted.

 

Dosage is of no concern. A cup of some sort that fits inside occupying all the space is desirable. It doesn't have to funnel anything nor be screened on the bottom.

As the oa sublimates, it will obviously off gas and come from the top of the cup.

I do like the idea of a unit using propane. It'll be my next project eventually.

I don't think heat is an issue as its only momentary, and I've already MacGyvered a unit for a heat gun and didn't have any problems.

I'm trying to strive for someone who has hundreds of hives look at oa vaporization as another daily task. Not some insurmountable task that would take days to do.

If it's got popularity in Europe, being that they've had the ability to vaporize legally for longer, it must point to the fact that there is legitimate validity to the idea.

 

I thought you were looking for input; it sounds like you have everything figured out already...

 

The high end vaporizers 'the kids are using these days' use a thermostatically controlled heated air.

This is stoner science, not rocket science.

You need to balance (via engineering or trial and error) the volume of air you want to move per second, the heat of the air, and a usable duty cycle for the air heating components (you have to be able to keep the air moving within a set temp range)...PWM the heating element is probably necessary if you want it to heat up fast and be able to maintain the heat within a reasonable range.

 

how does one heat something past it's boiling point in an open container?

 

Well, ever boil water for pasta?

 

Yeah it doesn't get hotter than the boiling point for your altitude here is a science ezperiement for you boil some water and take the temp once its rolling then let it roll for 20 min and take the temp again ...it will be the same why is that?

 

Medhat Nasr helped to develop one the expensive forced air units. I spoke with him a EAS a couple of weeks ago and he commented that the forced warm air will break up the cluster allowing you to treat the bees when temps are below freezing (Celsius). He had also developed oxalic acid in a pill form to save measuring and weighing out. Lastly he talked about the need to cool vaporizers between hives, otherwise half ends up vaporizing before you get it in the hive.

 

I'm inclining towards an active vaporizer and have not begun to consider a passive vaporizer. Nor will I ever.

When setting-out to design a product, prejudice really needs to be put to one side and ALL options considered, and so to dismiss passive vapourisation from the outset is, I suggest, a mistake.

It is practicable to make a vapourisation 'head' which will operate vertically or horizontally from a couple of inches of copper tubing, a suitably-sized bullet case, and a diesel pre-heater. And, if four of these are wired in series-parallel, temperature control is no longer essential (useful, but not essential) with only a timer being required.

If two sets of four such headers are made, then one set can be deployed whilst the other set is being re-located and re-charged with OA. Being of relatively low mass, a run from cold to cold (actually, warm to warm) takes around 5 minutes. If 10 minutes per application is allowed, to take into account re-locating the kit around the apiary, then 6 runs per hour (24 hives) can easily be achieved. Thus it is possible to treat between 100 and 150 hives per day, using cheaply made equipment.

If you really need to treat more hives than this per day, then why not shell out the necessary $500 for a turn-key multi-dosing system ? The cost per hive when the cost is amortised over (say) a 10 year period would be insignificant.

LJ

 

Are these heat guns being used in Europe have a thermostat on it? It has a digital display allowing you to set the temp. Obviously it has something to control heat output. The harbor freight one I mentioned in my first thread even has temperature settings. Just not a digital display.

I'm looking for input, yes. Mainly trying to get a housing idea figured out. That's where the good portion of the dilemma originates.

Are we stating that these units in Europe are a gimmick and that they don't actually work as intended? Looks like the units they're using are working just fine to vaporize the oa.

Passive vaporizing is not a consideration in my book because of it's downfall. That's why I'm speaking of the active vaporizer.

In my opinion, these active vaporizers are the solution. I've already stated why in my original post.

Consider these units and the time it takes to treat. Reference from the YouTube video in my first post and see, that treatment interval is 15 seconds per hive. Iirc, I didn't see how long the initial warm-up takes, maybe 5 minutes?

So do the math, in an 8 hour day with no breaks in between, you have 28800 seconds. You have a few warm-up periods, some refilling, and duty cycling. Regardless, with all taken into account, you could even treat at least 1k hives in an 8 hour day.

 

...you could even treat at least 1k hives in an 8 hour day.

For sure. I treated >200 hives yesterday evening with the heat gun version - after work. So it is really quick. Apart from the gas mask it is fun to work with. You need a good gas mask. The thing is pushed into the entrance, keep it for ten seconds or so and move to the next hive. There is smoke coming out of the hives for about a minute after the treatment, so pretty much everything inside got oxalic acid particles on it.

I take some pictures for you the next days, so you can figure the setup and construction of the device. Basicly it is a water pipe + a body of a water meter + an adapter fitting for the heat gun. You can screw off the lid which has a glass window in it. Inside that case there is a cup made of thin metal. The oxalic acid crystals are put into that cup, the hot air is flowing around the cup and heats the cup and thus the oxalic acid.

The heat gun has a temperature control. You need to wait about 5 minutes before hell breaks loose.

I will post pictures later.

 

Now, I can't remember, were you the fella that bought one of these Euro units?

 

Yes. The device comes from Italy. That is where I bought it:

http://www.legaitaly.com/en/cart/ap...iary/varroa-control/corpo-centrale-del-sublimatore-con-bicchierotto-inox-detail

Direct link to the picture of the device: http://www.legaitaly.com/images/stories/virtuemart/product/Corpo_centrale_d_511a6e54b21b5.jpg

Item number 8475100 is the main unit.

 

Bernhard, does it mechanically attach to the heat gun or do you hold the gun in one hand and the vaporizer in the other? How long do you vaporize for? Do you run the heat gun from a generator?

 

I have a power generator on my truck and a long power cord. 25 Meter/27 yards. The power generator must be strong enough, because the heat gun needs a lot of power.

 

It attaches to the heat gun. So in one hand I hold the heat gun+vaporizer, the other hand holds the power cord.
Yes, I run the heat gun from a generator on my truck. I don't unload it. I start the generator on the bed of my truck. This way I go from apiary to apiary. You need a strong generator. 4 kW or so, or the heat gun will blow the fuses and/or will kill the generator if you run it on too high power all the time.

 

Thanks! Does it attach to the heat gun with friction? or is there a clamp or set-screw? I use the dribble method now when wrapping the hives in early November, but I hate breaking the propolis seal right before winter.

 

A guy I know designed these and they get good reviews.

http://myhoosiervillebeekeeping.webs.com/oxalic-acid-vaporizer

 

I think those units get things a lot more complicated than my little hot-tray vaporizer. The real limiting factor on that unit is the battery/power source. I am looking for a way to power it with 110. As you say, that could be dealt with by a small generator or inverter if no plug-in is available. Speed could be achieved more easily with multiple units.

 

A short video on the construction of that vaporizer.

https://www.youtube.com/watch?v=IdaJ1jWpIPc

As said, basicly a water meter, enclosed in plastic. A metal cup inside the water meter holds the oxalic acid. The hot air is flowing around the cup on one side.

 

I sourced one of the lega units and a Steinel heat gun. There isn't really anything that holds the two together. A little bit of friction maybe. Probably ok if I hold it level, but if I tipped it down the Lega unit would fall off the heat gun. Are you using anything to improve the fit of the two?

 

Very cool! Thanks for posting that up. I just need to find a water meter supplier and try and come up with something. I might even bite the bullet eventually if I have no luck and buy this unit. Although, I'm struggling to understand how the dollar is so weak.

 

I've been tossing the idea around of making my own 120 v vaporizer- always keeping my eyes open for parts and pieces. Something of interest were the heaters we use in our equipment cabinets (Vulcans) but the elements are pressed and epoxied into an aluminum heat sink. Not possible to separate them without destroying one or the other, but I have seen these cartridge heaters with built in thermocouples on Ebay. I can't begin to guess the wattage needed and one would have to create a suitable casting for the acid bowl, but I see some potential there.

 

Any updates? Did the OP create this thing? Did it work?

 

I did finish my own unit, but it certainly is not as effective as the lega unit i bought instead.

Follow this thread instead:

http://www.beesource.com/forums/showthread.php?322101-Let-s-talk-about-lega-vaporizer-unit