Vaporiser design element idea: cool air inlet mechanism.

A thought came to me about what could be a fairly easy method of turning the design of a fixed temperature convection vape into a variable temperature one, without having to adjust the power to the element. This would be to have some way of introducing cool air into the hot airstream between the element and the herb. And of course, it should be possible to control how much air is allowed in, so the temperature can be tweaked to a desired level.

Exactly what form this would take, I'm not entirely sure, but what do you think? Maybe you have a clearer picture in your mind of how this could work.

This is a wonderful method of temperature control. It is exactly how I control temperature with my HI/TT. I just plug it into a constant (12) voltage power supply so it will always have the hottest temperature immediately available. I place the tip of my roasting tube just at the end of the HI/TT center tube and allow some room air to mix and give me just the right temperature in the roasting tube. The glass nipple also allows you to mix some room air by changing the angle with the center tube. It allows for a slower roast. Like "Mom's Marshmallow Method". The technique can be used on most fixed temperature vaporizers. It is nice to be able to change roasting temperatures instantly by mixing in room air. Manual control is nice since there are so many variables in the roasting process.
Have a happy toasty roasty day.

Nice. Yeah that method of yours makes sense. Though it's not quite the pecise control I was thinking of, it would clearly work. As long as your vape gets hot enough - fixed at a low temp is a bit of a problem (unless you boost the voltage).

Of course, what I had in mind was an inbuilt feature, and there could be many different ways of implementing this principle.

I don't know if i would like this feature rather than the common method of controling the power output of the element, because that way i can ensure i have a more dense and tasty hit.

Why do you think it would be better than the methods used today?

This method can get very precise i think, but needs to make sure that the hot and cold air get mixed well enough before hitting herbs. So it can vape evenly with no combustion.

I was thinking about something that was cooling down the herbs between hits to avoid any loss

I don't understand your reasoning here. Why would air cooled by a post-element inlet offer any less dense and tasty a hit than air that's simply heated by a cooler element?

Temperature dials/adjusters are just one more thing that can go wrong in a vape, and can be expensive and/or difficult to include in a design. A cool inlet could be very simple and reliable. And it could be a much quicker (indeed, instant) way to alter temperature. If you had a lever for opening and closing the inlet, you don't have to wait for the element or heat exchanger to cool down or heat up as you do with a voltage change. And with log vapes in particular, this can take a long time - as those with log vapes and variable voltage supplys will be able to attest.

this is starting to become conventional wisdom, but it ain't necessarily so ... i've got a year and a half on my Bud Toaster and there have been NO failures or problems with either the computer chip, the temperature sensor, or the buttons.

and i really don't see any advantage to adding some kind of throttled ambient air input. cooling the herb in the vial is not the problem to be solved. keeping a consistent temperature of the air flow past the herb is the fundamental issue.

many versions ago, when the BT was basically a log-type vape, the temperature of the herb would drop 50°F with a toke. once i actually measured what was going on in the herb, i was driven to add computer temperature control. it made a great difference -- providing the "best" extraction of vapor from the trichomes.

You're right, it may not be the case, if you're as serious as you are about it. The problem is that if something *does* go wrong, the average person is going to have rather more difficulty repairing a vape using low-tech features rather than one filled with PCB's, chips and other electronics. I guess that ultimately I have in mind a vague idea of an open-source variable-temperature convection vape design that anyone could make (or at the very least, maintain) without advanced tools, materials or knowledge - more-or-less a variation on the log vape.

Another possible advantage of a post-element air inlet (does that sound like a good name for the component?) is that with clever design, it could conceivably involve little to no extra material at all - a few well-placed holes in the air-path with a simple twist of a connection might be enough.

Well there's the engineering challenge - to make an air inlet system that results in a consistent temperature, whatever the setting. So the (from element) : (from inlet) airflow ratio would have to stay constant for different draw speeds.

I'm not trying to offer complete solutions here - I'm just sharing a brainwave.

re: brainwave -- understood. it's just that i've tried a lot of different designs and i'm not seeing an advantage.

re: repairing high tech -- agreed. reading through problems that are mentioned concerning log vapes, even soldering seems way beyond people's comfort zone. the reality is there needs to be an effective warranty.

i've given up on attempting to build my own PCs (i use 4 myself in my job, and gf uses 2) when HP makes such a nice All-In-One ... but if my PC goes from mostly dead to really fucking dead, it's time to toss and replace.

here's my thought about a Bud Toaster warranty. Standard 10 year exchange, no cost warranty, shipping included. However, for a $100 fee, you get a second Bud Toaster to use while waiting for warranty exchange.

Not really good enough for what I'm imagining. Dealing with returns isn't such an attractive option if you live half way round the world from the manufacturers, as I do here in Australia, and as does a certain toker from India I found on another forum, who wanted to make a vape. I sent him to a page with plans for a DIY conduction model, but I've been wondering if something more sophisticated could be an option.

The idea is interesting, but why waste energy running the element and airflow hotter than necessary and then cooling the air down again? A little like adjusting the speed of your car using the brakes while your foot is on the accelerator?
As for circuit reliability, that's why when designing the E-Nano I chose a simple inline dimmer at 120v and avoided using any type of power supply. In our house we’ve never had a dimmer switch fail, but we’ve had to replace plenty of power suppies.

It sounds like the E-Nano can change temperatures so quickly with 110V available that air mixing temperature control wouldn't be necessary. Although air mixing does allow for faster temperature changes. That is certainly true when designing HVAC systems (my last employment). The higher temperature operation may waste more energy for roasting, but works well for the aromatherapy and hand warming functions.

I am relying more on technique when not using a VVPS. Leaking some room air to cool the roasting air causes a whistle. The pitch will change with leakage rate. I just maintain a steady pitch to maintain a steady temperature. The roasting tube design plays a large part in the overall vaporizer effectiveness.

Qbit - I hear what you are saying about being halfway around the world. The ability for user serviceability is almost vital. It is so nice to be able to fix it yourself if necessary. The great thing about 12 volt power is that the adapters are available just about anywhere for any input voltage. You don't have to be limited to either 110 or 220 volts.

i personally have some concern about the E-Nano placing 110v AC inside the handheld vaporizer. Do you use a thermal cutoff to prevent unintended thermal runaway? Maybe the dimmer switch won't outright fail, but the few times i've used a potentiometer in a vape design, it would develop a null spot at the most used position after several months.

Yeah, this is a good point. But I guess log vapes run at much lower power than most other plug-ins, so that extra power to keep it hotter would only be a few watts. I usually keep my SSV on all evening, and that draws significantly more than a log vape.

Simply because there is more air to vapor ratio, you have more air mixed with the vapor extracted from the plant.
I think it is a good idea, and it is a simple solution to vary the temp but it is a tough one to implement effectively IMO.

Stems have different diameters and the air inlets have diferent sizes on the tube surrounding the heater in log vaporizers.. This would make it complicated to have a one size fits all solution. Or rather, it is easy to make it fit, not so easy to make it work the same way. As Alan said above, "The roasting tube design plays a large part in the overall vaporizer effectiveness."

The best way would be something like a slide piece that has several positions, but you would need to measure temps for each stem and vaporizer. And i'm still not factoring in the draw speed which will also interfere with the temperature. It could be a cilindrical piece that would fit between the center tube and the stem.

IMO, i would rather have an removable circuit that would act as a temperature regulator and adjust the voltage in the resistance automatically since this way it would be much more acurate. Being removable would allow to me have real temperature control in any vaporizer. This would be ground breaking.

If i want an inacurate control, i can use my logs controling the temp with draw speed, screen height and control the air leaks joining the stem with the center tube.

Short answer: There is no need for any thermal cutoff in the E-Nano design.
Long answer: The E-Nano uses a standard triac based external dimmer rated at 150 watts, not just a potentiometer. The ideal roasting temp is achieved with the E-Nano between 8-10 watts (depending on blend and personal roasting style.) The E-nano will most likely ship with a 10-12-watt heating element. You can leave it on full power 24/7 and the E-Nano is comfortably warm to the touch. I confirm this by touching the unit to the inside of my arm and against my face. At 10-12 watts it heats up in two minutes and gives the extra power needed for some concentrates.
I have tested the design up to 30 watts. At that wattage you begin to get some charring in the unit after the unit has been on for a considerable amount of time. At 20 watts the unit gets a little to hot to hold but there is no charring even with the unit plugged directly into a 110V circuit with no dimmer.