A downdraught OA vapouriser

[SixFooter]

A vapouriser with the 'T' shape of a gun might be the way to go - with the vapouriser in the handle, and a fan on the back, blowing air across the top of the pan and into the 'barrel' nozzle. That would certainly work. My only reservation with that type of design is operator proximity - personally, I do like to be a metre away when the stuff becomes airborne.

LJ

I was thinking of a short copper pipe pushed through the entrance and the heating unit and fan supported on a simple A frame /trestle outside, so I could connect to my battery and retreat in the same way as I do with the Varrox.

 

[dano41]

Little John great setup I would also like to have an arrangement for vaporizing through the feed hole.Was wondering if you'd seen this

 

[Little John]

Little John great setup I would also like to have an arrangement for vaporizing through the feed hole.Was wondering if you'd seen this

Thanks.

Wow - that looks like a serious piece of kit ! Love it.

Ok - so ball valve closed - spoon the OA onto the ball, close the sliding flap, open the ball valve ... and the OA drops down onto a pre-heated pan.

Have you got any more details on the internals of that gizmo ? Or maybe a link ?

I've got some suitable ball-valves ... you've got my mind racing now.

I had been toying with the idea of using pelletized OA - but couldn't see a safe way of dropping 'em onto a hot pan, and had been thinking along the lines of some kind of interlocked feed tube - but two ball-valves one above the other would do the job very nicely indeed ....

LJ

 

[Little John]

Ok - I've managed to track that gizmo down - due to the graphic of it being named 'Sublimalto'.

The business end of it is very unusual - looks like a tube squashed to form two fine jets. The ball-valve is closed and the tube containing the OA heated - and the only way out for the vapour is via those jets. Ingenious - not something I would have considered in a month of Sundays.

Next job is to translate the instructions to get a fuller picture ...

Many thanks for that lead.

LJ

 

[dano41]

Gist of text, if holes become blocked try to clear with pin or unscrew and clean with water.

 

[dano41]

Figure3 is for screwing out valve fig1 at underside of vaporizer.

 

[SixFooter]

I've been working on a prototype to blow vapour horizontally using the same method - computer fan and glow plug. However, in use , the OA does not go from powder to vapour in one step as with the varrox; it melts to a liquid, then evaporates. Does this matter ? I'm guessing it is ok just less sublime!

 

[wessexmario]

Those Italian sublimators are not cheap: 320 euros.

http://www.agrariaughetto.com/apicoltura/trattamenti-antiparassitari/#cc-m-product-5707642216

The instructions translate as follows:

Instructions for use of the Submilmator

- Connect the two terminals to the battery.
- Wait for the red light to turn off. (A)
- Place the sublimator on the hive over the feeding hole.
- Pour the oxalic acid into the tube B.
- Open the handle M to start the treatment.
- Wait for 1 minute for the sublimation treatment to finish.
- Move the sublimator to the next hive, reload the tube with oxalic acid.
- IMPORTANT Do not load the tube during the treatment.

During the sublimation of the hive, the holes of the nozzle can get blocked. Fig 1.

Try opening the holes with a pin, in that does not work, proceed as follows:

Turn the sublimator upside down. Fig 2

insert a socket spanner Fig 3 to unscrew the nozzle Fig 4 wash it with water and check the two holes are unblocked.

It is advisable when work has finished to dismantle the nozzle and clean it.

 

[Little John]

I've been working on a prototype to blow vapour horizontally using the same method - computer fan and glow plug. However, in use , the OA does not go from powder to vapour in one step as with the varrox; it melts to a liquid, then evaporates. Does this matter ? I'm guessing it is ok just less sublime!

Commonly-available oxalic acid is supplied as the stable dihydrate. It doesn't matter what kit you use to sublimate it - the first step (at around 102 deg C) is that the water (the dihydate part of the material) disassociates from the oxalic acid and boils off. It may give the appearance of 'melting', but it's just the free water being 'released' and about to turn into steam. What's left is anhydrous oxalic acid, which then sublimates (changes it's state directly from solid to gas) at around 157 deg C.

As the vapour leaves the hot surface it drops below it's sublimation temperature and thus returns to it's solid anhydrous form, as micro-fine crystals having the appearance of a fine white dust. These then adsorb water moisture from the atmosphere and return to the dihydrate form of the acid.

LJ

 

[Little John]

I've been working on a prototype to blow vapour horizontally using the same method - computer fan and glow plug.

Here's an idea I've been mulling over after seeing that Italian job:

It's basically a small-bore copper tube, sealed in the centre, with a diesel pre-heater poked in one end, and a .22 LR bullet case poked into the other, with a simple wire clip (not shown) holding the case in place.

The bullet case is a rim-fire job, and has 3 or 4 notches filed into it's rim. These will then act as jets.

The drill would be to pre-load the bullet case (or a number of them) with Oxalic Acid, load them into place, then present the business end to any convenient hole in the hive body. Horizontal or vertical, it wouldn't matter. The OA would exit the business end as jets of vapour (in theory, anyway ... ), and all that would be required is a flange of some sort around the copper tube to butt up against the hive body

If it works - then multiple cases of OA could be prepared beforehand, and as these are removed after use, the jets would effectively become self-cleaning ...

I think this could work - all that's required now is to source a small quantity of LR .22 rimfire cases to play with.

LJ

 

[SixFooter]

Here's an idea I've been mulling over after seeing that Italian job:

It's basically a small-bore copper tube, sealed in the centre, with a diesel pre-heater poked in one end, and a .22 LR bullet case poked into the other, with a simple wire clip (not shown) holding the case in place.

The bullet case is a rim-fire job, and has 3 or 4 notches filed into it's rim. These will then act as jets.

The drill would be to pre-load the bullet case (or a number of them) with Oxalic Acid, load them into place, then present the business end to any convenient hole?kf in the hive body. Horizontal or vertical, it wouldn't matter. The OA would exit the business end as jets of vapour (in theory, anyway ... ), and all that would be required is a flange of some sort around the copper tube to butt up against the hive body

If it works - then multiple cases of OA could be prepared beforehand, and as these are removed after use, the jets would effectively become self-cleaning ...

I think this could work - all that's required now is to source a small quantity of LR .22 rimfire cases to play with.

LJ

Seems like it would work, but why not just copper pipe? Why the bullet cases

 

[SixFooter]

Commonly-available oxalic acid is supplied as the stable dihydrate. It doesn't matter what kit you use to sublimate it - the first step (at around 102 deg C) is that the water (the dihydate part of the material) disassociates from the oxalic acid and boils off. It may give the appearance of 'melting', but it's just the free water being 'released' and about to turn into steam. What's left is anhydrous oxalic acid, which then sublimates (changes it's state directly from solid to gas) at around 157 deg C.

As the vapour leaves the hot surface it drops below it's sublimation temperature and thus returns to it's solid anhydrous form, as micro-fine crystals having the appearance of a fine white dust. These then adsorb water moisture from the atmosphere and return to the dihydrate form of the acid.

LJ

Makes sense, but the glow plugs must be at a higher temperature as I saw all the powder change to a clear liquid which then formed a vapour. The powder in the varrox seemed to go straight to vapour, but took more than twice as long to process. Looking at the varrox working again, you can see a little water boiling off, so you are no doubt correct about what's going on.

 

[Little John]

Seems like it would work, but why not just copper pipe? Why the bullet cases

Well - there's a need to form a reasonably small jet, and at the same time be able to load the OA somehow into some kind of heatable container - a reversed bullet case (or something very similar) was the only thing I could think of to achieve both at the same time.

Once you start adding compression fittings, ball-valves and such-like (as with the Italian design), you're incorporating substantial mass which will increase warm-up and cool-down times considerably.
Which is not much of a problem for the 2 or 3 hive person, but would seriously slow down operations for those with (say) >50 hives.

But - this is still very much a 'back-of-a-***-packet' design at the moment - so any ideas of how to improve it would be appreciated.

What I very much like about the Italian design is the formation of a jet of vapour resulting from the heating of the OA. Clever. So no need for a fan anymore, and the jet can be pointed in any direction. What I don't like about it is the need for pre-heating ... and of course the price !

LJ

 

[Hivemaker.]

Those Italian sublimators are not cheap: 320 euros.

The Sublimox from Italy is 399 euros, but could be made a lot cheaper.

 

[wessexmario]

Here's an idea I've been mulling over after seeing that Italian job:
LJ

an even more interesting scenario... "would you accompany me to the station to explain that white powder, electrical device and bullet cases Sir?"

Why not just use some 10mm or smaller copper tube and a yorkshire fitting?
A short piece of tube, squashed at one end to provide a flat end with pin holes for jets, will push fit the other end into into a yorkshire straight connector, which can be attached to the heating device.

 

[Little John]

Why not just use some 10mm or smaller copper tube and a yorkshire fitting?
A short piece of tube, squashed at one end to provide a flat end with pin holes for jets, will push fit the other end into into a yorkshire straight connector, which can be attached to the heating device.

That could be an idea worth pursuing - but with a plain capilliary fitting, not a Yorkshire, as they have solder rings incorporated.

One reason I chose .22 cases was that this diameter is close to that of the diesel glow-plug. The other being that rimfire cases are (for all intents and purposes) non re-usable, and thus being so much scrap metal wouldn't attract the attention of plod.
Incidentally, .22 LR rimfire blanks can be obtained quite legally by anyone over 18 (FAC not required) by post, for £15 a hundred. Seems a waste to buy cases like this, but it may be the only way to obtain them. Shooting clubs don't seem over-keen to supply - probably not worth their while for a couple of quid's worth of scrap metal.

LJ

 

[Hivemaker.]

If it works - then multiple cases of OA could be prepared beforehand, and as these are removed after use, the jets would effectively become self-cleaning ...

I think this could work - all that's required now is to source a small quantity of LR .22 rimfire cases to play with.

How many grams of oxalic will a .22 LR casing hold?

 

[Little John]

How many grams of oxalic will a .22 LR casing hold?

Good question - haven't a clue - that's why I was rather hoping to scrounge a couple to find out. Probably not very much. Could be gently tamped-down of course to increase the load, or maybe use a couple side-by-side ?

The problem with the bigger cases - say, 9mm/ .303 - is that although they'd definitely be big enough, they can be re-used to make live ammunition. They can be sourced from the US via Ebay of course - by the bucketful - for very little money, but I rather think that our customs guys may get a tad excited when they X-ray the parcel.

LJ

 

[Hivemaker.]

They can be sourced from the US via Ebay of course - by the bucketful

I'm sure i could get a few 270 and 243 cases for you, get through a few around here on the deer.

 

[jenkinsbrynmair]

Can spare a few empty cases if you like - in whatever calibre you'd like. PM me if you want some (remember that postage charges over 10 kilos can be prohibitive )