Heating power of a 20 watt infrared bar diode?

rhd said:

Cannabidiol - Wikipedia, the free encyclopedia

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Ah. Well you could have linked to cannibidiol on chemspider and saved my question heh. It has it's own entry.. different from the one you posted, so I figured your molecule was something similar, but different.

Oh my bad. That chemspider page was where wikipedia took me to justify the 200 degree vaporize point. Chemspider has a bunch of info like flash points, etc.

When I smoked weed, I used a lighter, Instead of a 20W bar diode

DeeLuxx said:

Im still keen on using a laser though as they... give us a better compound to study

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Source?

i know a girl that is going to a univervisty here in my city that is in a botany program. she is doing something that sounds similar to you. But in her class they are using a 532nm laser. i thought it was strange, but she assured me it is a green 532 dpss.

DeeLuxx said:

Hi there,

I am currently studying botany at university and for a current project we are studying the toxins and pheromones within different plants etc.

To do this we vaporize plant matter and extract different compounds.

im interested in building my own using an infrared laser bar diode as the heating element - this one is for sale on ebay Oclaro 20w 808nm DCS diode laser bar Prolite | eBay - same as in the picture pretty much

So my question is what would be the ability of a bar diode to heat a 2cm x 2cm sample of plant matter evenly and effectively to around 200 degrees Celsius?


is this even possible with a bar diode? would i have to use lenses?

i understand that i wont need all of 20watts otherwise it will probably set the sample on fire

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Oh really? interesting. What university is she at?

And i do you know the power output of the dpss? dont really think i could get my hands on one of those though....

i could see if they have one in the engineering department but i doubt it

You might try a small, inexpensive microwave oven... your sample should go into a sealed flask which is exposed to the microwaves and the vapor routed to a collection container which is under a small amount of aluminum foil that is KEPT AWAY from the oven's walls. A quantity of water in a glass in the oven will moderate the energy transfer and slow the heating... you'll need to play around with several runs to get the feel if the moderator is even required and then gauge the heating time to secure the volatile compounds in sufficient quantities to study.

interesting idea - especially the water to moderate temperature. ill probs have a go at this sometime soon because its sounds easy.

We usualy route the vapours striaght through a liebig condenser and condesnse the vapours into a liquid which we then isolate different compounds from.

How about regulating the power output of the magnetron to regulate temperature?

she goes to the university of california riverside. I don't speak to her much, and i don't the remember the power out put.

michael.

If I was you I would try to contact this man...

YouTube - ‪NurdRage's Channel‬‏

NurdRage from youtube is a self professed chemist expert. He is quite smart and has designed and tutorialized some experiments (which I find fascinating), as well as been all over the states, going to many chemist functions and events. This could be another avenue that you would like to explore.

DeeLuxx:
My opinion is that routing through the oven wall with pyrex tubing for external vapor collection would be the ideal situation... the aluminum foil idea was just for a quick-test as a proof... before drilling holes in the break-room microwave!
From just observation, it appears that most microwave ovens in the cheap category prefer to cycle the tube on/off rather than dealing with true power control; hence the reason that I suggested water as a moderator. However, I did a bit of Googling and found a reference for a tissue preservation unit built at the UC Berkeley with a cocky name 'True To Power' control system... check with the CNR Biological Imaging Facility, Steve Ruzin, PhD or Denise Schichnes, PhD or research this link: http: //microscopy<dot>berkeley<dot>edu/MRA/index<dot>html

To stay on topic, however, you can avoid many of the issues presented by members regarding energy absorption and IR power by simply doing a little out-of-the box thinking about laser energy absorption... rather than directly radiating the plant specimen, put the material into a container and heat the container from the outside with the IR laser energy. This is kind of a calorimeter approach and lends itself to ease of temperature control and temperature monitoring. The calorimeter (oven) can be created out of a number of high-absorption materials (carbon) or can be glass coated on the outside with an appropriate high temperature IR absorbing coating (paint?) I've used black bar-B-Q spray paint on a few projects and it is good for up to 1200F. Remember, as you increase the mass of the oven, the time period for cooking the plant material increases, so it is critical to design small. It may even be possible to create a closed system where the material is at one end of the oven (tube bulb) and the vapors are ducted forward to an absorption/capture area. Such an approach would allow for micro-filtering along the duct and would make it very easy to create a well balanced temperature differential to facilitate vapor condensation.

Ray

That's what I meant in post #4 about 'passive elements between the sample and the laser diode'. Though as I said then.. IMHO.. doing it this way offers zero benefit over using a normal heating element.. and those are a lot cheaper than laser diodes.

bobhaha said:

If I was you I would try to contact this man...

YouTube - ‪NurdRage's Channel‬‏

NurdRage from youtube is a self professed chemist expert. He is quite smart and has designed and tutorialized some experiments (which I find fascinating), as well as been all over the states, going to many chemist functions and events. This could be another avenue that you would like to explore.

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I thought I was the only one here that watched nurdrage!!

"Though as I said then.. IMHO.. doing it this way offers zero benefit over using a normal heating element.. and those are a lot cheaper than laser diodes. "

Amen!

But sometimes cost is not the critical factor, the "WOW factor" would be enhanced with a few IR laser diodes and thermocouple sensors and a few PICs to monitor and control things... He's in research... it's embarrassing to go to WalMart and buy a $3 coffee-cup dip resistance heater to use to vaporize his samples... even if it works as-well or better than the laser! I spent a year in a college research lab, I know that WOW is important to the profs.

Ray