Microdosing Capsule Vaporizer

[Farid]

I wanted to share a design which I have been working on in my free time. I have no plans to manufacture this, but I wanted to share the idea with likeminded people here on FC.

The premise of this design is to make a vaporizer which combines the heat exchanger and the dosing capsule into one entity. Unlike other vaporizers in which dosing capsules are optional, this vaporizer would be designed around dosing capsules, and the capsule would be required in order for the device to function.

The main goals with this design were to:

1) Create a capsule which utilizes microchannels, to optimize heat transfer, and allow for incoming cold air to be preheated significantly, thus reducing temperature drop during inhalation.

2) Create a capsule system in which a hot/spent capsule can be ejected by depressing the mouthpiece. Likewise the mouthpiece can be stored inside the device during transport.

3) Create an on demand electric conduction vaporizer designed around small doses and single big hits.

Here are some pics:

Animation:


Outside View


Door Removed


Bottom View:

Capsule (outside):

Capsule (cover removed to show microchannels):


There’s a lot that would still need to be ironed out for this design to go anywhere. The chip and electronics still needs lots of work. Tolerances haven’t been accounted for, and the frame design would need some tweaking to accommodate easy manufacture and assembly.

I mostly threw this together to show the capsule/heat exchanger combo design. Let me know your thoughts.

 

[invertedisdead]

Nice work, I had a somewhat similar idea for a convection design using a capsule as the heater. I'm not a huge proponent to using capsules personally so I haven't messed with it too much though outside of conceptulization on an iPad doodle.

I like the concept of warming up the air to reduce temp loss during a draw. I guess my question would be: can the capsule design be manufactured for less than the premise could be accomplished in software utilizing draw sensing; paired with an an optimized low mass heater for fast response time? Sort of like the mechanics behind a Grasshopper, but conduction centric.

What material where you thinking for the capsule design?

 

[Farid]

Nice work, I had a somewhat similar idea for a convection design using a capsule as the heater. I'm not a huge proponent to using capsules personally so I haven't messed with it too much though outside of conceptulization on an iPad doodle.

I like the concept of warming up the air to reduce temp loss during a draw. I guess my question would be: can the capsule design be manufactured for less than the premise could be accomplished in software utilizing draw sensing; paired with an an optimized low mass heater for fast response time? Sort of like the mechanics behind a Grasshopper, but conduction centric.

Thanks for commenting, I really love what you're doing with the InVersion.

The capsule idea came about because I wanted to make an on the go microdosing flower vape. I figured capsules would allow users to load the vape without handling flower directly. I also figured that with a very small oven with micro channels, it should be easy to remove and clean. I thought that by making each hit from a new clean oven/capsule, some of the negative conduction flavors could be reduced.

Since this was totally conceptual, I wasn’t factoring cost into the equation at all. I came up with other cheaper designs for the capsules which used folded sheet metal or screens as baffles, but I decided to go with this design because it allows the air to travel a longer distance, and has a greater mass.

I’m not sure how draw sensing would compare to this. I went this direction since my background is mechanical. I also have a feeling that increasing the heater power via draw sensing is going to lead to slightly less dense vapor at the beginning of a hit compared to heating the incoming air through channels.

What material where you thinking for the capsule design?

That was something I was hoping to get input on. I considered some kind of ceramic cover over a metal inner cup part, but I know the ceramic would break quickly with expansion.

 

[nms]

Very cool design. Is the heating element an inductance coil or resistance?

It's quite similar to a dynavap cap, I don't see why you'd use different materials.

I wonder if there are airflow concerns if the air can only go through these small holes.

I believe it's important for the outer part of the capsule, including the channels to be metal, even more if you want to heat via induction. The inner part could be a less conductive layer to prevent as much conductive heating and keep it truly on demand. This is if you're not using the glass for this purpose and loading the stem instead?

 

[Farid]

This would be resistance, which is why I'm concerned about the material used. This part of the design is where I think there is the biggest hole, I'm afraid that handling the coil will mess with the resistance, and possibly cause safety concerns. If I were to really try and experiment with this design I would increase the frame size in order to accommodate a better DNA chip, for safety's sake.

I'm a huge fan of everything dynavap, it's what I pretty much exclusively use these days. I've certainly considered 316 stainless steel and Ti as ideal material candidates, but I wasn't sure how they would effect the resistance of the coil. The other difference is that the cover to the capsule is not designed to be removed regularly, like a dynavap cap is. It's also designed to be hit while heating, versus the dynavap, which is heated and then hit.

I'm not trying to prevent conductive heating, I want conductive heating as efficiently as possible, since I want optimize battery life. The channels are to reduce heat loss due to convective cooling, but not to bring the air up to temperatures which would cause convective vaporization. Similarly the airflow is intended to be restricted. I want this to be a "mouth to lung" type hit, which is pretty much impossible with convection.

And you're correct, the flower would be loaded inside the capsule, the airpath is not a stem, but just a tube to carry the vapor.

 

[nms]

Yeah, sounds good. Have you thought that given the current design the heat may propagate towards the 'chassis' too much, causing it to become very hot and on the other side increasing the amount of wattage needed to heat the load, as heat is lost?

How do you address the specific issue of keeping the heat as much in the oven as possible?

This would also affect the choice of external materials. For instance good things like PEEK or ULTEM or other high performance plastics become less of an option if they are near a 250ºC metal part.(metal would work as a major heatsink)

 

[Farid]

That's a great point. I considered adding a glass (or other insulating material) cylinder around the coil chamber, but I figured the large area of air around the coil may be sufficient. I think the large hole in the bottom will also help in this regard. The thin wall adjacent to the battery was my biggest concern, but this could be alleviated by making the entire device a few cm longer, so that the coil is no longer adjacent to the battery, but rather slightly below it.

The coil posts are the spot where I'm most concerned with heat transferring to the chassis. Right now I have them surrounded by some kind of insulation, but I haven't run any simulations to determine if that is enough, or if the area around the posts will still get too hot.

 

[nms]

One other thing is that most of the heating element's surface is actually in contact with air. What if you integrated this heating element inside say a casing of a thermally but not electrically conductive material so that most of the heat generated was actually passed to the capsule, which you could then have a much wider contact area with?

 

[Farid]

That's an interesting idea, I'm not sure how it would play out.

My concern with casing the coil in a thermally conductive material is that more heat would then be transferred from that casing to the chassis. You could make the casing "floating" as well, with a layer of air around it, but the overall size of the heater would be increased, thus reducing the volume of the air pocket around it, reducing it's insulating potential.

Since the heater is designed for on demand 1 hits, and not back to back hits like with a session vape, it wouldn't need to store heat very long. So a lower mass heater might be preferred. I think by the time the casing would get up to temperature, the hit may already be over. I've got a feeling the capsule may conduct heat quicker (since it is a smaller diameter than the outer casing, and it is surrounded entirely by the coil).

But this is all based on assumption, testing could prove me completely wrong.

 

[nms]

I mean, a casing could take no more than 1mm additional space. I mean embedding the heating element in a almost same width metal piece. On the other way, you could just carve half the heater into the outer capsule and just insert the inner capsule, instead of both sides coming out.

Just suggestions, because I feel there is a significant loss from having such a small area of contact between heater and capsule.

Since you'd have a far bigger contact area with the capsule, it could actually make the system need less wattage to reach a certain load temperature.

 

[invertedisdead]

Thanks for commenting, I really love what you're doing with the InVersion.

The capsule idea came about because I wanted to make an on the go microdosing flower vape. I figured capsules would allow users to load the vape without handling flower directly. I also figured that with a very small oven with micro channels, it should be easy to remove and clean. I thought that by making each hit from a new clean oven/capsule, some of the negative conduction flavors could be reduced.

Since this was totally conceptual, I wasn’t factoring cost into the equation at all. I came up with other cheaper designs for the capsules which used folded sheet metal or screens as baffles, but I decided to go with this design because it allows the air to travel a longer distance, and has a greater mass.

I’m not sure how draw sensing would compare to this. I went this direction since my background is mechanical. I also have a feeling that increasing the heater power via draw sensing is going to lead to slightly less dense vapor at the beginning of a hit compared to heating the incoming air through channels.



That was something I was hoping to get input on. I considered some kind of ceramic cover over a metal inner cup part, but I know the ceramic would break quickly with expansion.

Thank you!

Regarding your design: The end user wouldn’t really need access to see the air channels right? What if the capsule and cover were consolidated down to a single piece? Would probably be cheaper to manufacture at scale and you wouldn’t have to mess with pairing dissimilar materials. How were you mating the capsule to the heating element? Friction fit?

Also, if the capsule was built from a high conductivity material, it wouldn’t be that picky about the heating element configuration as the material itself would heat more evenly which would help compensate for that. Of course, “high conductivity materials” comprise a quite small list and would depend on personal preference/design philosophy.

 

[Farid]

The user wouldn't need to access the air channels, but I think it would be ideal for them to be able to remove the cover somehow so as to be able to give the capsule a deep clean. There would also be a domed screen at the bottom of the capsule to stop bud from clogging the holes at the bottom.

I imagined the bottom being slightly crimped to stop it from falling out the bottom. But I also considered just going with a press fit if the materials were the same. The downside to this is that it would make deep cleaning the channels more difficult.

A single piece capsule would be cool, but press fitting a tube wouldn't be too costly either. The costly part would be making the micro channels, since some precision would be required.

 

[KeroZen]

Nice. But you really want to use a MOSFET to switch your heater current on and off. Your small switch won't last very long otherwise and there's a risk it can "stick" in the on position, as the arcs create micro welds. Check in the e-cig world schematics for MOSFET mech mods, it's not too complicated.

 

[Hippie Dickie]

Your small switch won't last very long

been there, done that - what @KeroZen says is true - even 3A is enough to damage a switch or potentiometer. MOSFET for the win!

 

[Farid]

Indeed, I intend to switch out the board with something more robust if I were to ever build this (which is unlikely, I have other projects in the pipeline). This was just a stand in while I demonstrate the capsule ejection. I just figured these drawings could inspire someone, and stir some discussion, but they're certainly not blueprints to follow for a build.

If I were to build this, I would partner with an experienced mod builder, and would focus my energy entirely on the heat exchanger/capsule system.