Cold Fire You Can Touch - DIY Cold Plasma Torch

okay we are at about 35 all right what you just saw was prototype number four of a cold plasma torch that a friend and I have been working on for the past year or so spoiler alert while number four looked very cool all that whooshing is actually a sign of it not working but I'm getting ahead of myself before I jump to version 18 which actually works and produces a beautiful cold flame we need to back up and first understand what these things are and what they're trying to do first I said these torches are cold plasma torches and that's true the flame that comes out of the end is a hair over room temperature and you can touch it without issue but how is that possible and why would I want such a thing the reason I wanted a torch like this are threefold first cold plasma is amazing and I just wanted to see it for myself I'd heard about a years ago and have wanted to try and make some sense I mean honestly telling somebody that you made a torch that makes cold fire will have them looking at you like you're a wizard instantly second wall it's cold enough to touch the plasma is full of highly reactive charged particles and when it touches microorganisms it rips and shreds so it's a powerful tool for sterilization that won't damage the thing it's sterilizing it even kills viruses and spores in theory and finally all that reactivity makes it the perfect thing to do some really interesting chemistry with for example you can mix some co2 into the argon gas that this is run on and it'll convert it to carbon monoxide and o2 the form of which is a very important industrial feedstock and we'll do it at crazy high efficiencies or feed in a mix of co2 and hydrogen and it'll convert it to methane and other hydrocarbons and leaving a lot out but you can see the appeal of a thing that in theory turns air and water into fuel beyond that I knew that all the skills necessary to build these torches are basically the exact same skills needed to build other hotter plasma torches and little ion engines in fact all of these torches are technically ion engines just maybe not very efficient ones without a bit of tweaking so once I have a vacuum system set up I'll be able to quickly make some ion engines which ought to be a lot of fun now all that sounds amazing but we still haven't discussed what cold plasma is and how we make it plasma is the fourth state of matter after gas to review a solid as atoms held together firmly a liquid is atoms held together only very Loosli and gases atoms that can only interact weakly and move around freely all the interactions in these cases are mostly mediated by the electrons orbiting the atoms a plasma takes all this one step further under the right circumstances typically when a gas gets ridiculously hot the electrons orbiting the atoms can be given enough energy to detach from their host atoms and float around freely themselves when this happens the various atoms become highly charged due to a lack of electrons and it forms a soup of charged particles fire is actually a really good example of this in the chemical reaction that causes fire an enormous amount of energy is released allowing the electrons to come off for a moment until things cool down you can actually see all this happen if you watch a match in slow motion striking the match generates Sparks and a cloud of gases and when the to mix the chemical reaction gets going in things heat up quickly the gas begins to glow from a mixture of blackbody radiation also known as heat glow which is proportional to its temperature and the ionization of atoms and molecules in the mixture for more about both I've put a link to my spectroscopy video where we explore both in detail however something important to understand is that there are two sets of temperatures in a plasma the electron temperature and the ion or atom temperature with fire because of the way the energy is released the atoms themselves get very hot as the reaction progresses and the electrons whiz around crashing into things and in fact in most plasmas the same thing happens as you put more energy into it the temperature of the atoms will rise rapidly but we wouldn't be talking about this today if that was the only option if you could somehow apply energy in a way that just heats the electrons and had some way to keep the atoms cold you would still have a glowing plasma whose electrons are anywhere from two to fifteen thousand degrees but it would feel cold to the touch as electrons lack the momentum to transfer much of that heat to a large object due to their tiny mass the reason fire feels hot is because gases and ions are at high temperatures and since they have more mass they can transfer that energy to your finger more easily okay now that we understand the basics of plasma how do we make some well anyone who's played with high voltage knows that a sufficiently high voltage source lets you pull long streams of plasma as soon as the wires get close enough together what's happening there is the electrons and the wire have sufficient energy to literally shoot out of the wire and travel a fair distance in search of ground so they can release their energy as the wires get closer together some of the electrons make it across the gap as they do this they crash into gas molecules and ionize them knocking more electrons free this makes the air more conductive so more electrons can flow this repeats until you have a hot soup of plasma which conducts it very readily at that point trillions and trillions of electrons can suddenly flow which rapidly heats everything up what we want to do is take advantage of the electrons jumping out of the wire but we need to inhibit their ability to cross the gap and form a hot arc to give them a little extra help we don't want to just use higher voltages instead we want to increase the frequency of the applied voltage until it's in the low radio ranges if we use something like a microwave transformer to generate our high voltage it'll be running at 60 Hertz that means the voltage climbs and drops 60 times per second considering the distance the electrons fly is proportional to the voltage there are these distinct Peaks where more electrons are coming out and flying further by increasing the frequency we increase the amount of time the electrons are able to escape the wire however as we increase the frequency we also start to get what are called near and far field effects radio is after all just an alternating current on a set of bare wires at its simplest by increasing the frequency all the way into the low radio ranges the wire now also radiates radio waves along with the electrons it spews out these waves can themselves energize the flying electrons allowing them to fly further and behave differently primarily it easily allows them to fly free of the wire and try to find ground to release their energy to maximize the effect of the high voltage high frequency we place a thin insulator between the two wires as a dielectric barrier as the electrons leave the wire they now hit a surface that they can't really go through so they spread out and the insulator builds up a charge on its surface essentially forming a tiny capacitor if this insulator was a tube we can set it up so that all the electrons are being spit out into a stream of easily ionizable gas like argon the electrons would ionize the gas turning it into a plasma and the RF would help keep it energized if we get the gas flow just right we should be able to gently push this plasma out of the tube the flowing gas makes it such that the electrons absorb most of the energy as the gas atoms just aren't exposed to enough energy to heat them up in the short time that they're in the tube before we go further a word safety we're working with high voltages and gasses which if not handled properly can be very dangerous I wouldn't suggest you attempt to replicate this unless you know what you're doing use common sense and good high voltage practice if you intend to replicate this with that out of the way to build a torch around this concept is simple in theory but very difficult in practice the core of the torture these 1.3 millimeter quartz capillary tubes we're using a flyback transformer and zvs driver as our power source both of which can now easily be purchased online for cheap sly backs are great because they run at fifteen to thirty thousand volts at a fairly high frequency in the kilohertz but they're also super weird so even though they oscillate and output an alternating current depending on the model the output voltage goes from 0 to some positive voltage and then back to zero without really going negative it's more like pulsed DC so you treat them sort of like AC and sort of like DC again super weird but useful for our purposes to make a bit of cold plasma all you do is take a capillary put a needle down one end and a small washer or a bit of metal on the outside connect the back end to an argon tank and each electrode to the flyback and once you turn it on voila instant cold plasma now if we're just gonna talk about cold plasma this would be basically the end of the video in fact most of the papers about this just stop here they run their tests with the capillary exposed like this and just stop thing is attempting to actually utilize this in an actual functional tool is a lot harder than one might think so now we can finally talk about model 18 and briefly what happened to the rest I'm gonna have to leave a lot of the prototyping and failures out as I spent more than 70 hours machining parts for the various versions over the past three weeks many of these were failed attempts at making a torch and having them break at the last second designs that refused to work for one reason or another or quick prototypes like the basic exposed capillary just to test ideas materials and concepts to understand the design I settled on we're actually going to start with number 17 as it's almost identical to 18 but all the parts are see-through so we can see what's going on the body of the torch is a piece of acrylic tubing with a 3/8 inch inner diameter it was cut to approximate length and then trimmed to dimension on the lathe so it had nice flat ends the back is sealed with a brass hose fitting I made that has an o-ring at one end and is the connection point both for the inner elect and the wire that connected to the power supply I had a lot of fun making this part as it was the most geometrically complex part and brass is just a fun material to turn the front end has an acrylic plug that is also sealed by an o-ring and has a small channel going down the center then it has a slightly wider bore at the front end the inner electrode which is made of a needle soldered onto some copper wire can fit up through the channel and the capillary can be slid down the channel over the needle once everything is assembled this prevents you from breaking the capillary while trying to fit the needle down the hole to make sure the capillary doesn't leak gas around its outside which is why number four failed a silicon gasket is used to plug the hole so that the gas can only come up through the tube in number four you can actually see the gas being ionized outside of the tube because argon could leak through the sides I'm using some scrap RTV silicone I had from the gecko tape project I'm working on to make little gaskets I made a die to cut them out using some 2 millimeter copper tubing with a flared end this gasket is pressed into place and sealed by the upper electrode which is made of a piece of brass tubing I didn't have any brass tubing so I just made my own this tubing has in turn held in place by an acrylic shield which is meant to protect the capillary from getting bumped and snapped the main feature of this design is that every part is quickly and easily replaceable as what killed many of the previous designs was a cap Hillary or other part breaking and not having an easy way to replace them a small leak is enough to destroy one of these torches so early versions used adhesives like epoxy to make a perfect seal this made it impossible to fix so after a few of those failed 17 was made to be perfectly fixable 18 is similar but with a few changes first a spacer made of Delrin was added to the back end to make sure that the high-voltage electrode was not directly touching the acrylic second the front plug was replaced with an identical one made out of Teflon this too was to make sure that no electrode touches the acrylic the shield was shortened to the internal bore was significantly widened and it too was made out of Teflon actually repurposed the front end of number four for this so why did we make what seemed like superficial changes well 17 had a single issue which was that no matter what we did we could not make plasma come out of the end of the tube it took a while to figure out but our theory is that acrylic is one of several materials that holds a charge very well as the high voltage charged up the plastic it was inducing an electrostatic charge in the shield that was literally forcing the plasma back down the tube and we can't just feed in more gas as too much gas kills the flame as no ions can build up before being shot out of the tube so 18 was meant to address all of these issues after a bit of tuning we had a really nice flame and the torch was stable enough to use without fear of breaking it quick note about the power supply is that the larger wire on the flyback should be connected to the front electrode and the thin wire goes to the inner electrode it's kind of counterintuitive but the big wire is actually where the electrons flow towards so we want the cathode which is where the electrons come out of to be in the middle which happens to come out of the bottom of the transformer now I'm gonna have to burst your bubble a bit here the glow from this flame is super dim all the images you've seen or long exposures for compare person here's what it looks like with the lights on not not super impressive is it in person it's bright enough to see when the lights are off but my camera struggles to pick it up without a long exposure like we discussed earlier flames are bright because most of their light comes from heat glow or blackbody radiation only very small amount comes from ions recombining and emitting their particular spectra since our plasma is basically room temperature all the light comes from ions emitting light so it's pretty dim though the very high electron temperature does mean that it puts out a lot of UV light we just can't see it now consider that I had to hold my finger in the flame for 30 seconds to get this image I think it really demonstrates that it's pretty cold and here it is shooting at some paper even directly in the flame for over a minute nothing happened it does feel pretty cold to the touch because of the rather significant gas blow so where do we go from here well now that we have this torch we plan on using it for a variety of experiments I really want to try some of that chemistry with it but it'll take some time to make sure that we do it safely and can quantify it properly I also plan on writing a paper on this torch design and a lot of the specifics on what it takes to make it work these things are so fiddly to get working and the only other plasma torch paper that uses this cheap and readily available power supply ended up with a hot plasma because they did it wrong so I'm excited to show how it can be done properly beyond that we'll continue to tweak the design and add bits and pieces I'm exhausted from this project and I'm pretty burnt out on making torches no pun intended but I do want to come back to it and add a microwave emitter to the front to see if we can increase brightness and efficiency of plasma creation off-camera I'm going to build an icebox to house all the electronics and a stand for the torch then it'll be added as the latest tool in the lab for all my sterilization needs this project was an absolute monster a year in the making dozens and dozens of hours of machining and even more of testing and retesting things I almost gave up a few times but I'm glad I stuck with it as the results are awesome point is getting projects like this working can be very expensive and it's my supporters here on youtube over on patreon and now on Kofi that make them possible many of you ask what I do for a living and you're looking at it making these videos is my full-time job and it gives me the freedom to explore and create amazing things like this so thank you so much for your support in keeping these science videos coming and if you're new and would like to support then there are some links in the description if you're looking for more content and be sure to head over to my other social media pages to see images sneak peeks and updates long before they make it into videos that's all for now and I'll see you next time

Channel: The Thought Emporium

Views: 1,952,698

Rating: 4.9261942 out of 5

Keywords: plasma, fire, cold fire, cold plasma, non thermal plasma, corona, corona discharge, high voltage, electrons, dielectric, radio, microwave, flyback, zvs, zvs driver, flyback transformer, transformer, quartz capillary, green energy, carbon capture, co2, argon, plasma torch, machining, lathe, acrylic, metal, brass, turning, non-thermal plasma

Id: jRZkrrcDKb0

Length: 14min 19sec (859 seconds)

Published: Wed Apr 24 2019