Replacement for nichrome coil...

**Scubabatdan** · 10-26-2009, 06:55 PM

Originally Posted by Jason365

I like the look of that Dan. Would the ceramic piece around the heater be replaceable or is a all in one unit? i.e. would the sun rod come out to aid in cleaning?

Jason

It would be a seperate unit, the rod could be removed for cleaning, but the entire assembly woud have to be removed for that. The outer casing would act as a heat shield so no ones fingers get burnt. The inner heating element can be slid into place, but making it perminant i do not believe is necessary. As the first couple uses should bake a seal into place so fluid does not flow to the bottom. Have been thinking about that issue.
Dan

**Quit4myKids** · 10-26-2009, 07:53 PM

Dan, I like the basic principle of pooling the fluid, but I forsee implementation and usage problems. We run into the problem off running it dry and getting really hot, since pooling the liquid over the heating area is going to keep the heating surface cooler than the spec. Where would the liquid go once one was done vaping? Probably to the side and bottom, where it would evaporate (overnight, or over a few days on non-use), creating a gooey, stick mess.

I think we are better off only delivering the liquid we are ready to vaporize, and keeping the heater at as consistent a temperature as possible. If we only use 40% of the heating surface, the heater will recover faster, as the unsaturated heating area will conduct heat to the saturated area.

I really wish I had your graphics skills!!

Kinabaloo, the magical circuit is a trade secret, and he would reveal it to me. Based on what I've seen, I believe it is a rolled up flexible coil of traces (picture just the conductive traces from a printed circuit board). The "control" is in the material used, and how long, wide and thick those traces will be when the circuit is printed. I'm sure there are some fairly complex calculations that one could use to build a spreadsheet to project the heat and resistance based on voltage and ohm requirements, and could even calculate the required physical properties (trace material, trace length/width).

I'm not sure if that addresses it for you. I'm expecting to chat with the rep again late this evening, so if there are any specific questions that haven't already been addressed in the thread, now would be a good time to ask.

Q4mK

**Some Guy** · 10-26-2009, 10:14 PM

It is Just a concept test. A prototype of a prototype.
Keep it simple as possible.
The only thing I don't care for is the cold tip of non porous ceramic. I think it will just be in the way. The "cold tip" should be porous like is already used and can be added easily enough.

Just my 25 cents

**Scubabatdan** · 10-26-2009, 10:27 PM

Originally Posted by Quit4myKids

Dan, I like the basic principle of pooling the fluid, but I forsee implementation and usage problems. We run into the problem off running it dry and getting really hot, since pooling the liquid over the heating area is going to keep the heating surface cooler than the spec. Where would the liquid go once one was done vaping? Probably to the side and bottom, where it would evaporate (overnight, or over a few days on non-use), creating a gooey, stick mess.

I think we are better off only delivering the liquid we are ready to vaporize, and keeping the heater at as consistent a temperature as possible. If we only use 40% of the heating surface, the heater will recover faster, as the unsaturated heating area will conduct heat to the saturated area.

I really wish I had your graphics skills!!

Again I dont think it will pool persay, I created that design in case of flooding, if the element is wicking the fluid then I doubt that it will pool since it has to runn down a hot element in the first place in order to "pool" But having a say .5mm space between the heating element and the ceramic holder will be close enough to vaporise any fluid that does pool IMO.

And how should we only using 40% of the heating area? 6mm in the holder, 4mm for the juice to run down (Hot) and 2mm of contact area to wick the juice?

Dan

**kinabaloo** · 10-26-2009, 10:45 PM

Originally Posted by Quit4myKids

Kinabaloo, the magical circuit is a trade secret, and he would reveal it to me. Based on what I've seen, I believe it is a rolled up flexible coil of traces (picture just the conductive traces from a printed circuit board). The "control" is in the material used, and how long, wide and thick those traces will be when the circuit is printed. I'm sure there are some fairly complex calculations that one could use to build a spreadsheet to project the heat and resistance based on voltage and ohm requirements, and could even calculate the required physical properties (trace material, trace length/width).

I'm not sure if that addresses it for you. I'm expecting to chat with the rep again late this evening, so if there are any specific questions that haven't already been addressed in the thread, now would be a good time to ask.

Q4mK

Q1: How is the temp set? At manufacture or can be set/adjusted later?

Q2: The circuit will allow fast heat up but then limit the temp to the chosen figure? (Part of the secret is probably PWM, the second part is how the sensor works and controls the PWM).

Just to be clear that we have full temp control - give this scenario: we set a temp of say 175C and it indeed is, at 3.7v. It will still be 175C even if someone connects it to a 5V supply?

So if we said 3ohm coil at 3.7v then the current would be ~1.2 A and the power in just over 4W. Ask the person to confirm if given a temp target of say 175C and the likely dimensions (this will affect the heat capacity), that a heat up time of no more than 1/2 second is possible (or a lower resistance would be better).

**Ralph Hilton** · 10-26-2009, 11:03 PM

I think this matter of the temperature needs clarifying!
From my understanding the circuit is a purely electrical one which limits the current as temperature goes up due to the electrical characteristics of the metals used. If that is the case then and the temperature specified is the stable end temperature then that temperature will take a while to stabilize - perhaps several seconds as the power will be decreased when it is close to that temperature. So if one wants a temperature of say 200C to be reached fairly quickly then it will be necessary to specify a somewhat higher temperature as the one at which the device stabilizes - perhaps 250C.
I really don't see that a sealed device such as detailed could have a built in pwm.
The way I think it works is that specifying 3.7 volts and 200C would mean that running it on a higher voltage would result in a higher temperature. Lowering the resistance of the device would result in it reaching its target temperature faster.

**SurfVortex** · 10-26-2009, 11:04 PM

Hope I am not too late...
My opinion runs with the team as far as all of the minimums go. My experience is that VG starts to vaporize at 175C, so I would suggest an Optimal Surface Temp. of 200-225C.max.(we want to stay away from 260C.-the Mr. Hyde conversion temp.)
Length of Non-Heated Tip- no opinion.
Also, I think the standard atty resistance is around 3-3.5 ohms.
THANK YOU Q4MK!!!!!!!!!! for your dedicated work.And THANK YOU to everyone participating in this thread! This is truly amazing and beautiful!

SV

**roadkilldeluxe** · 10-27-2009, 12:57 AM

Originally Posted by kinabaloo

Q1: How is the temp set? At manufacture or can be set/adjusted later?

Q2: The circuit will allow fast heat up but then limit the temp to the chosen figure? (Part of the secret is probably PWM, the second part is how the sensor works and controls the PWM).

Originally Posted by Ralph Hilton

From my understanding the circuit is a purely electrical one which limits the current as temperature goes up due to the electrical characteristics of the metals used.

It sounds like Quit4myKids is just speculating, but "Based on what I've seen, I believe it is a rolled up flexible coil of traces (picture just the conductive traces from a printed circuit board). The "control" is in the material used, and how long, wide and thick those traces will be when the circuit is printed. I'm sure there are some fairly complex calculations that one could use to build a spreadsheet to project the heat and resistance based on voltage and ohm requirements, and could even calculate the required physical properties (trace material, trace length/width)."

I have a feeling that's pretty accurate. I would guess that it uses PTC principles to reach the target temperature. In that case, Ralph would be correct about the slower stabilization near the upper bounds.

**kinabaloo** · 10-27-2009, 02:53 AM

Originally Posted by Ralph Hilton

I think this matter of the temperature needs clarifying!
From my understanding the circuit is a purely electrical one which limits the current as temperature goes up due to the electrical characteristics of the metals used.

No combination of metals will achieve much in terms of temp control. It is surly done by the chip. Just want to be sure that is the case.

Must sleep now (2am here). Will catch up tomorrow ...