KeroZen
Chronic vapaholic
Interesting remarks. Allowing to control the air flow rate is I think the only way to enable precise temperature control. It took me a while to be able to phrase it precisely.
With conduction vapes with feedback loop temperature regulation, the temperature is always at or below the set temperature. They are able to usually control pretty well how hot the bowl is, but if you draw too fast you can overcome the conductivity rate of the bowl material (usually ceramic or stainless steel) and thus the temperature of the material inside the bowl drops below the set-point.
Back then there were already two schools: open air flow like the Ascent or restricted air flow like the Solo (to name the two extremes) With the former it was nearly impossible for non initiated users to get good hits, it required quite the self control to create the regulation, otherwise nearly all of them drew too hard or fast and got only wispy vapor. With the Solo it was the inverse, the vape created the right amount of restriction such that it was easy to get vapor, if you drew too fast the vape would restrict you so you were always in the right zone. But of course this came at the cost of comfort with many people finding the restriction unbearable (the famous golf ball through a straw comparison)
Fast forward to convection vapes and we find ourselves in a comparable situation excepted it's reversed: they tend to be at or above the set temperature, because they can not adapt to the flow rate because they don't measure it (some vapes have draw detection but to my knowledge none has any real air flow rate sensor, as it's either pricey and/or impractical)
We also have open air flow vapes like the Milaana, where you have to create the restriction yourself, either by forcing to slow down your draw or by letting the screen clog a bit. At the other end we have the CFV / SwiftPro which have the exact same characteristic as @Prolusio described above: if you force too much you're not getting more, so in a way they ensure you are always drawing inside a very narrow rate band.
And this is the key! The SwiftPro is the only temperature regulated full convection vape that I have that is able to create the "level depleted" effect that I have with my Ascent and other properly regulated conduction vapes (i.e. you can set a given temperature level, deplete completely the level until vapor production almost stops, then as soon as you raise the temperature to next level, production restarts, proof of excellent regulation)
Even with the Project or the iHeat using TC mode with good mods and/or firmware, it's the same as with my manually regulated convection vapes: it's is possible to extract the entire bowl at any given temperature setting provided you get enough time... because naturally you will draw harder and longer as the session advances and this is what creates the "automatic temperature stepping" effect. It's not the (very limited) amount of conduction created by the SS or glass bowl (proof is, I get the same with @Alan's wood stem in the iHeat and the bowl is almost cold at the end) (or well, more precisely it's the inverse, the bowl mass is robbing less and less heat from the system over time, but it's not that, the effect is minimal)
Without draw rate sensing, even with very good temperature regulation at the coil(s)/heater (and in fact the better the regulation the truer the following is) the temperature at the material will rise the harder you draw. The heater will keep heating more and more air at the right temperature (if properly regulated it doesn't drop much or at all, especially if you give it ample power like we do) thus more hot air is available, the bowl material receives more calories, extraction temperature gets higher and this is what gives us the temp stepping (@Shit Snacks this should put words on your "just a number" remark)
So if we want true temperature regulation with (on-demand or not) convection we need either:
1) use flow rate sensing on top of temperature sensing in a closed loop
2) have the vape create a flow rate restriction (at the cost of people complaining like for the CFV)
3) force ourselves to always draw at the exact same rate and strength (at the cost of requiring a technique and being not user-friendly and noobs complaining they got nothing or that it's not working)
PS: (3) can be eased by using so much power that the heater can't be overwhelmed, allowing to draw at nearly any rate (like the Tubo, but at the cost of excessive power consumption) but it doesn't solve the "temperature regulation at the bowl location" aspect
PS2: with conduction the important variables are known: it's based on the surface area, and the heater is fixed so it becomes a constant. With area, coef of conductivity and temperature, we have all important parameters. With convection we are dealing with a moving mass of air, but we just monitor the temperature and not the flow rate, it's evident that we are missing half of the equation.
With conduction vapes with feedback loop temperature regulation, the temperature is always at or below the set temperature. They are able to usually control pretty well how hot the bowl is, but if you draw too fast you can overcome the conductivity rate of the bowl material (usually ceramic or stainless steel) and thus the temperature of the material inside the bowl drops below the set-point.
Back then there were already two schools: open air flow like the Ascent or restricted air flow like the Solo (to name the two extremes) With the former it was nearly impossible for non initiated users to get good hits, it required quite the self control to create the regulation, otherwise nearly all of them drew too hard or fast and got only wispy vapor. With the Solo it was the inverse, the vape created the right amount of restriction such that it was easy to get vapor, if you drew too fast the vape would restrict you so you were always in the right zone. But of course this came at the cost of comfort with many people finding the restriction unbearable (the famous golf ball through a straw comparison)
Fast forward to convection vapes and we find ourselves in a comparable situation excepted it's reversed: they tend to be at or above the set temperature, because they can not adapt to the flow rate because they don't measure it (some vapes have draw detection but to my knowledge none has any real air flow rate sensor, as it's either pricey and/or impractical)
We also have open air flow vapes like the Milaana, where you have to create the restriction yourself, either by forcing to slow down your draw or by letting the screen clog a bit. At the other end we have the CFV / SwiftPro which have the exact same characteristic as @Prolusio described above: if you force too much you're not getting more, so in a way they ensure you are always drawing inside a very narrow rate band.
And this is the key! The SwiftPro is the only temperature regulated full convection vape that I have that is able to create the "level depleted" effect that I have with my Ascent and other properly regulated conduction vapes (i.e. you can set a given temperature level, deplete completely the level until vapor production almost stops, then as soon as you raise the temperature to next level, production restarts, proof of excellent regulation)
Even with the Project or the iHeat using TC mode with good mods and/or firmware, it's the same as with my manually regulated convection vapes: it's is possible to extract the entire bowl at any given temperature setting provided you get enough time... because naturally you will draw harder and longer as the session advances and this is what creates the "automatic temperature stepping" effect. It's not the (very limited) amount of conduction created by the SS or glass bowl (proof is, I get the same with @Alan's wood stem in the iHeat and the bowl is almost cold at the end) (or well, more precisely it's the inverse, the bowl mass is robbing less and less heat from the system over time, but it's not that, the effect is minimal)
Without draw rate sensing, even with very good temperature regulation at the coil(s)/heater (and in fact the better the regulation the truer the following is) the temperature at the material will rise the harder you draw. The heater will keep heating more and more air at the right temperature (if properly regulated it doesn't drop much or at all, especially if you give it ample power like we do) thus more hot air is available, the bowl material receives more calories, extraction temperature gets higher and this is what gives us the temp stepping (@Shit Snacks this should put words on your "just a number" remark)
So if we want true temperature regulation with (on-demand or not) convection we need either:
1) use flow rate sensing on top of temperature sensing in a closed loop
2) have the vape create a flow rate restriction (at the cost of people complaining like for the CFV)
3) force ourselves to always draw at the exact same rate and strength (at the cost of requiring a technique and being not user-friendly and noobs complaining they got nothing or that it's not working)
PS: (3) can be eased by using so much power that the heater can't be overwhelmed, allowing to draw at nearly any rate (like the Tubo, but at the cost of excessive power consumption) but it doesn't solve the "temperature regulation at the bowl location" aspect
PS2: with conduction the important variables are known: it's based on the surface area, and the heater is fixed so it becomes a constant. With area, coef of conductivity and temperature, we have all important parameters. With convection we are dealing with a moving mass of air, but we just monitor the temperature and not the flow rate, it's evident that we are missing half of the equation.
