Ruby Casting (verneuli flame fusion)

Here's what I have for the top chamber where the powder goes. I need to find a rust stripper to clean out the inside of the pipe. Took me about 10 hrs to make the top plate and weld the threaded cylinders into, sand blast the outside and de-mold the furnace body. Super time consuming.

 

So I've found an issue. I found out that the HHO hydrogen generators make hydrogen mixed with oxygen. Not two separate streams of gas like I had thought. This is a problem because my burner design has a separate oxygen and hydrogen line that only mix outside the burner. If I used HHO gas it would be pre mixed inside my burner and I'd run the risk of the flames burning back inside the body of the burner tube.

I can think of a couple solutions but I'm interested to hear your thoughts on them.

One solution would be to custom build a hydrogen and oxygen generator that has separate streams. I found an example on YouTube but the design looks a bit underpowered compared with dry cell hydrogen generators. This may be able to be scaled up for 15 liters of gas production but I'm unsure if it would do what I need.



Another option is to simply redesign and remake the burner so it uses mixed HHO gas and won't burn back into the burner tube with some kind of arrestor inside the burner tube.

There may be other options I haven't thought of.

Also I found this design which is very interesting. Its a DIY oxygen generator that is simple to make and seems very efficient 15 L output with 96.8% pure oxygen gas made. It has applications for my project and also for replacing oxygen tanks for welding purposes around the shop.

 

What does your local welding gas supplier charge for hydrogen gas?, it may be worth just buying hydrogen and oxygen.

 

I think its 60 for oxygen and unsure about hydrogen not something they stock from what I've seen. I need to run the machine for 4 to 10 hrs for one gem. So that would be an entire tank easily each gem.

 

Still it would be a pretty large ruby boule you'd get after 10 hours. If the hydrogen isn't too expensive it would let you test the machine and debug with a known good gas before having to develop the gas generator unit.

 

These so called "water torches" with mixed gases use a flame arrester to prevent flashback in the holding tank. It seems to work on the commercial units. I do not feel very confident about that for large volumes.
Marks suggestion makes sense if you could find the H2.
For o2 its easy to find a used oxygen concentrator on CL. That's what I use for oxy-propane welding. The can get up to 95% so I am not sure if that is enough for your application?
Robert

 

What if you just built a large electrolysis tank or O2 concentrator and then used an oil free compressor to pump the gases into storage tanks?



Robert

 

I'll have a good look at that video.

I picked up 2 oxygen concentrators (5L/min max) each but I have yet to test them. They came from junk yard and had service tags on them that said not high enough purity oxygen or something to that effect. I'll open them up and see if I can figure out whats going on and resurrect them. Should at least give me some extra oxygen to play with.

As for the hydrogen. I'd like to build a pure hydrogen / oxygen splitter with separate lines but I'm pretty hazy on exactly how that is done. I've been unlucky with my googlefu and haven't found clear diagrams or explanations of how. There's one youtube video where a guy does it but I don't understand the current flow or plate setup exactly. Not enough to copy it and scale it up.

I found some hydrogen flash back arrestor on Amazon for up to 120 liters per min. Might be enough capacity for the system. Its brass as well.

I admit I'm feeling pretty stuck regarding the hydrogen and oxygen. I'm unsure if I can use straight browns hho gas with an arrestor on the lines or if that would cause issues and if I really need separate lines to fine tune the burner.

I am also unsure if I can use the 25 v output from the welder. I think I can. I read it produces less heat built up in the water when run at 25v but again there isn't a lot of info on it. Just one post stating it reduces heat build up.

 

Here is my understanding for what its worth. Electrolysis of water starts at around 1.2v. Voltage above that, some gets wasted as heat but also drives more current through the electrolyte for more gas production. You can and should add electrolytes to the water to lower its impedance. Various salts are used but NaCl will work. The generators typically use a stack of stainless plates forming cells, insulated from each other with alternating polarity from the power supply. The hydrogen and oxygen come of every other plate so the collection system must account for this to separate the gases. Hydrogen being an electron, accepter will come off the negative plates. Oxygen from the positive. Browns gas will have the perfect stoichiometric ratio and should not require adjusting. It would be safer to accumulate and store these gases separately as you know.

Your 25v power supply should be good. If you construct 20 cells at 1.2v per cell you would need 24v. I would consider starting with 10 cells and see how it goes experimentally. One thing to keep in mind is that if you don't insulate between the cells the middle plates will produce H2 and O2 (one gas on each side) since the are the negative plate for one cell in the series and the positive plate for the next. If you are making Browns gas, you don't care. If you are making separate gases you need to have and insulator between cells. You could also run a setup in parallel wiring at a lower voltage.
Let me know if that is helpful or I am telling you what you already know!
Robert

 

I have seen people use stainless wall switch plates for the generator plates but they are kind of thin. With your capabilities I would consider getting a scrap stainless appliance door (refrigerator?) and cutting plates out of that. I envision a stack of plates with plastic spacers held together with threaded rod. Maybe the plates have tabs on them for connectors? The gas collection will be a little intricate for separate gasses with a small hood over each plate.

The O2 concentrator may be hard to fix. They use a mineral called Zeolite that eventually "wears out". If you could find a source to replace that you might be good.
Robert

 

Hmm images are broken in the last post. I think zeolite is just a sand. Not sure how pure it needs to be. I'll take a look at the concentrators and see if they are repairable.

Also I've seen some hho browns gas setups that use neutral plates between the live ones. Not sure exactly why but it seems to improve efficiency somehow. See the pic below (3 plates between the tabs that stick out each side. The left side would be + and right side - connection with the neutral plates not connected to anything just floating there).

I think I need approx 80 to 100 plates for 15 L per minute production. I'm not sure if a plate produces the same amount of gas in an hho setup or a separator setup but I think it probably does. Might make a separator system extremely large since more space is needed between plates to hook up the collection tubes.

Might be worth it to just buy or build a large 80-100 plate hho browns gas setup and modify the burner so it uses the gas. I can also add extra oxygen into the burner with the concentrators. I read that the crystal growing environment should be oxidizing especially when trying for sapphires since the iron needs to be oxidized to the right state to impart the blue color. So I'll likely need to add more O2 at some point.

I think the main thing with using browns gas over seperate lines is that I can't change the individual concentrations as easily and also I don't know if the flame will burn back into the 2mm diameter capillary tubes back into the body of the burner or if the flame will be stable outside the tubes. I think it might be stable outside because people use browns gas for torches and they don't seem to back burn. Also if I can add extra oxygen then I'm essentially able to change the concentrations to get what I need albeit in a roundabout way.

I priced it out. I have seen some 80 to 100 plate setups on ebay for around $330 which isn't too bad. The cost of materials is $150 to 250 for all the gaskets, acrylic plates etc.. never mind the time to nicely cut out each plate and drill all the holes. I think it might just be worth buying a premade hho generator at that price.

 

Wait, what now Kelly?? You built oxygen generators?! And what's this about a crystal growing business?? What kind? Details ! Thats super interesting.

I'll open up the generators and have a look. The outer plastic casing is kind of mangled anyway and they will need a new housing.

I'm switching back to day schedule Sunday onwards. I'm so happy to finish this month of night shift. Its sucked bad and I've had 3 nights off over the past month. Can't get a lot done project wise with that kind of time constraint.

 

Great information Kelly! Hey, could you rejuvenate the zeolite with just a long bake in a kiln or is the flowing dry nitrogen absolutely necessary. That might be more efficient but adds complexity.
Robert

 

Very interesting. Well I may need to lean on your experience to fix the concentrators. So you think the zeolite is the most likely problem with them and putting out "low purity O2?" Or are there other issues that might cause it?

I'm not interested in compressing the gasses at all. I think someone else brought that up but I think its a bit too dangerous and complicated for what I'm doing.

The main reason I don't want to use bought gas is because of the huge expense and long run times. I don't think a hydrogen or oxygen tank I could reasonably buy would last for 4 hrs at 15 liters per min feed rate. I think the only way to do this is with a generator.

Do you know if I can send browns gas through a silicone drying chamber without causing problems? Do you think it needs to be dried before use? Or is water vapor not that big of an issue?

 

My only gas supplier, Air Liquide has 6 cubic metre cylinders for AUD $260 or USD$ 190. So 6000 litres / 15 litres per minute = 6.666 hours run time.

You could also dissolve zinc in hydrochloric acid to get hydrogen only, maybe have plates of zinc that can be raised and lowered to control the crude rate. Bottle up the remaining zinc chloride and sell it for soldering flux.

 

Still a lot of money to use per one growth cycle. I'd rather try use an hho system. The resulting crystal is only worth $30.

If I needed to could I buy two smaller hho generators and hook them up in parallel? That would cut the welder output from 25v to 12.5v each hho correct?

I'm still hazy on 12 vs 24 v power supply. Seems some sellers aay their cells are only 12v capable and more voltage will overheat water and cause steam. This doesn't make total sense to me since I've seen other sellers use 100 v output to the cell and all the hho systems seem to be made from the same 6x6" stainless plate. There aren't any electronics involved. Any idea what would work or if I should get one big hho unit of 15 liter output or two smaller ones that combined make up 15 L?