Sciencemadness Discussion Board

Fume cupboard door imploded

itchyfruit - 15-8-2009 at 14:54

Yesterday i finished my fume cupboard,ignited a small pile of smoke comp in it to test it switched the extract on about 10/15secs later the 5ft x 2ft double glazed door imploded with a loud boom followed by crash of broken glass it scared the crap out of me!!!
I know why it happened(no air inlets)and have since fixed the problem and the door.
I was gonna tell you lot yesterday, but i was to pissed off,i now see the funny side and i'm sure some of you will too.

I might start a itchys blunders thread :D

kclo4 - 15-8-2009 at 15:39

Interesting, Its a very good thing you tested it, isn't it?

What exactly is a fume cupboard? I thought they were fume hoods.. but if it is air tight there is something seriously wrong with your fan lol

itchyfruit - 15-8-2009 at 16:30

A fume cupboard(or atleast my 'fume cupboard') is an old shop display fridge(the type you usually see full of cans of coke etc) with a 'henry hoover' with the bottom cut out bolted and sealed on the top,the outlet is piped down and out through the wall at low level(thus avoiding neighbourhood panic) it now has 2 air inlet holes at the bottom!!

I would post a little video of it working,but i don't know how. I'm pretty pleased with it, i can completly fill it with smoke and empty it in about 10secs,it's filtered too.

kclo4 - 15-8-2009 at 16:44

Wow that sounds pretty cool, well.. youtube is always an option :)

itchyfruit - 15-8-2009 at 16:56

My girlfriend would show me how to put it on youtube,the problem is how to do a link thingy :D

kclo4 - 15-8-2009 at 19:14

Seriously? ... a URL?

JohnWW - 15-8-2009 at 21:55

Quote: Originally posted by itchyfruit  
Yesterday i finished my fume cupboard,ignited a small pile of smoke comp in it to test it switched the extract on about 10/15secs later the 5ft x 2ft double glazed door imploded with a loud boom followed by crash of broken glass it scared the crap out of me!!!
I know why it happened(no air inlets)and have since fixed the problem and the door.

Polycarbonate would probably have been a better choice of glazing material, instead of ordinary window glass. Toughened safety glass would also have been better, being stronger and breaking into relatively safe glass granules.

entropy51 - 16-8-2009 at 09:16

Quote: Originally posted by itchyfruit  
A fume cupboard(or atleast my 'fume cupboard') is an old shop display fridge(the type you usually see full of cans of coke etc) with a 'henry hoover' with the bottom cut out bolted and sealed on the top,

If 'henry hoover' is a vacuum cleaner like any I have seen, the gas stream blows right over the motor, normally a motor with sparking brushes.

Rather than explosion-proof, they are explosion-guaranteed.

I was unlucky enough to see a reaction run in hexane run away and blow out the reflux condenser in such a setup. We all survived, but the windows in the building did not. The fire marshall was not amused. Luckily it was a legitamite business and the drug squad had to go away without arresting anyone.

itchyfruit - 16-8-2009 at 13:32

Yes a URL (i think) but i don't have a clue how to do it.

I didn't have any say in what glass came with the fridge as i acquired it for free from my local shop,but i have used perspex as a replacement (i happened to have some) but yes polycarbonate would be better!!!

Yes a 'Henry hoover' is a vacuum cleaner, i'm not sure if the gas stream blows over the motor but i'll have a look.I don't do many flammable solvent type experiments it's more for extracting smoke etc.

kclo4 - 16-8-2009 at 16:00

All right, wel if you need help with the video, or pictures, that is, if you even want to show people,I'd be more then willing to help you out. Just PM me.

itchyfruit - 16-8-2009 at 17:09

Cheers, i don't suppose that many people will want to see it,but i'd like to do it anyway :)
I'll pm you tomorrow when i have made a video.

EmmisonJ - 17-8-2009 at 07:22

i'd love to see it :)

itchyfruit - 17-8-2009 at 14:16

Here it is, thanks kclo4 for the offer of help but meshell came to my rescue.
It might not be impressive to you guys but I think it's cool.
Here it is;


http://tinyurl.com/pcr2cl

EmmisonJ - 18-8-2009 at 05:19

good show! where'd you end up putting the air inlets?

like what was mentioned earlier i would just be weary of your vacuum being an ignition source, don't use any flammables in there until you get a vacuum source that isn't going to spark/etc

kclo4 - 18-8-2009 at 10:45

Ha! I like it. That is pretty cool, but I bet that is pretty annoying having that vacuum be so loud, right?

Even my little motor on my fume hood annoys me a ton though

itchyfruit - 18-8-2009 at 13:35

I put the air intakes at the bottom,and when i've decided on a final position for it i'm gonna put a couple of in-line sealed fans in these won't cause any sparking problems and be a lot quieter.I'll just use the vacuum for rapid smoke extraction.

It's got a lot of room for improvement, but it is a work in progress :)

Everado E. Dinavo - 19-8-2009 at 16:35

That's pretty neat that you can shut the door on that thing. Have you tested it with the door open to see if it will do as a regular fume hood as well?

itchyfruit - 20-8-2009 at 00:56

Thats a good point, i'll give it a go later and report back ;)