Dry ice & ducting

[Nick LX]

Does anyone have some top tips for dry ice machines and the use of ducting? We've got a cumulus dry ice machine (drop pellets in water type) and can't seem to get it to work very well with a length of ducting about 3meters long. Any tips or ideas would be great.

 

Thanks

[paulears]

A common problem unless you can improve the flow rate. I've not tried a duct fan, but could be worth an experiment, they're a bit loud, though. Duct on pea soupers has never worked well for me, but 8" duct works much better on a short length. I think the problem is that the capacity of the duct itself is an appreciable proportion of the machines output, just to fill it

[Ynot]

The problem with ducting dry ice (or indeed smoke) is that the confines of the ducting itself serves as a condenser, causing the fog to dissipate far quicker than in the open air.

 

But the more twists and turns in any direction you have the more likely the output is to drop in volume and pressure. And of course ducting the dry ice fog UP at any point is going to have serious downsides. :(

 

I've used fans before now to get some more pressure but with limited success, as the addition of more air speed usually breaks up the fog inside the duct so whilst you may get more speed the volume drops quite drastically.

 

That said, I've used Pea Soupers with ducting tightly fitted to the nozzle and ensured a good tight seal on the Souper lid and dropped a larger than normal cage load of ice in which gets a good head of fog built up quickly under reasonable pressure - generate the pressure by virtue of the reaction with the hot water and the effect will be better.

 

Had a quick Google for the Cumulus machine, and it looks pretty much like the Souper, so with experimentation you should get a reasonable effect.