there's no cfm rating...but the air force blew me across the room.

fan for flowhood?
Started By
MurCurY
, Mar 18 2006 12:40 PM
6 replies to this topic
#1
Posted 18 March 2006 - 12:40 PM
#2
Posted 18 March 2006 - 12:43 PM
Looks like about 600 cfm... there's a post for the calculation here somewhere. Sorry man, I'm stoned and too lazy to find it for you!
#3
Posted 18 March 2006 - 05:23 PM
Looks like a good blower. You should get yourself an AC motor speed control. Running a blower that big will make holes in your HEPA. DON'T USE A REGULAR LIGHT DIMMER. A proper speed control will be in the $30-$50 range.
Start with the controls turned down way low. Put a lit candle in front of the HEPA (about 4 inches away) and turn up the speed control until the candle flame looks like this:
http://mycotopia.net...52&d=1136040458
The candle flame should be almost horizontal when airflow is correct.
Here is a motor speed control, mounted in a weather proof box. I highly recommend getting a box with a cover to avoid accidentally changing the speed setting. AC fan speed control:
http://mycotopia.net...51&d=1136040458
Never run an AC fan at less than %30-%40 power. You can damage the motor by running it too slowly.
Here is a thread on creating a laminar flow workstation from Rubbermaid tubs:
http://mycotopia.net...read.php?t=6707
Start with the controls turned down way low. Put a lit candle in front of the HEPA (about 4 inches away) and turn up the speed control until the candle flame looks like this:
http://mycotopia.net...52&d=1136040458
The candle flame should be almost horizontal when airflow is correct.
Here is a motor speed control, mounted in a weather proof box. I highly recommend getting a box with a cover to avoid accidentally changing the speed setting. AC fan speed control:
http://mycotopia.net...51&d=1136040458
Never run an AC fan at less than %30-%40 power. You can damage the motor by running it too slowly.
Here is a thread on creating a laminar flow workstation from Rubbermaid tubs:
http://mycotopia.net...read.php?t=6707
#4
Posted 18 March 2006 - 06:24 PM
why do you suggest NOT using a dimmer switch?
#5
Posted 18 March 2006 - 07:34 PM
Dimmers are actually just beefy transistors with a variable resistor (potentiometer) to change voltage levels. They work by varying voltage. A light dimmer will "leak" amperage, even at low voltage levels, to a high resistance load like a blower. Excessive amperage will lead to heat build up, made all that much worse by the fan only running at 1/2 speed to remove that heat. Also, the amperage load of a decent sized blower will fry a light dimmer pretty quickly.
A proper speed control will vary voltage AND current simultaneously (motor speed controls use rheostats, not potentiometers). If you just vary voltage, you will get a lot of heat bulidup (and grease breakdown, and finally, failure) in the blower..
A light dimmer will work, but it will put a lot of extra strain on the blower.
A proper speed control will vary voltage AND current simultaneously (motor speed controls use rheostats, not potentiometers). If you just vary voltage, you will get a lot of heat bulidup (and grease breakdown, and finally, failure) in the blower..
A light dimmer will work, but it will put a lot of extra strain on the blower.
#6
Posted 18 March 2006 - 07:50 PM
save money by doing it right
in the long run.
in the long run.
#7
Posted 18 March 2006 - 08:08 PM
I remember you mentioning something about having Plexiglass to work with. Regardless, here is laminar flow station that has worked extremely well for my FOAF:
http://mycotopia.net...read.php?t=6707
PLEASE send us pics and success rates from your new hood...
http://mycotopia.net...read.php?t=6707
PLEASE send us pics and success rates from your new hood...