Re: Re: [PSUBS-MAILIST] Scrubbers

["Sean T. Stevenson" <sts@telus.net>]

As far as quieting the fan, try placing it somewhere that is not directly 
exposed.  For example, have the intake low in the sub (one concept I have seen 
is a perforated floor within a cylindrical hull, with air intake under the 
floor).  The air travels through a length of vacuum cleaner hose, for example, 
to the fan which is mounted next to your scrubber (all insulated for noise and 
temp.), through another length of conduit to a high point in the sub for 
redistribution.  The only noise you would hear in that case is air flow at the 
inlet, which can be minimized by sizing correctly.

If you want redundancy, use two fans, but both need to be strong enough to 
circulate enough air on their own.  Cycle them so that they both run equivalent 
hours.

Oversizing a scrubber fan doesn't really have a detrimental effect, other than 
possibly increasing the total current draw of your electrical system.  The 
scrubber material will not be consumed any faster by doing this, and in fact, 
it may be useful to have a percievable airflow through the hull, to reduce 
condensation on interior surfaces.

-Sean


Quoting rjune@fuse.net:

> Try using Dayton Fans.  You can find them in a McMaster-Carr Catalog.  There
> available in round or square, AC or DC, and with lots of accessories, guards,
> filters, etc.  So that you can find the fans that I'm talking about look for
> part number 1976K37.  In this case its a 120mm (4.69") Square Fan with
> 25.4mm(1") depth, 61cfm, 12VDC, .108amps 
> 
> Also remember to not oversize your fan.  I would think that you only need
> enough cfm to replace the air in you sub approximately every 3 to 5
> minutes.
> 
> For example a sub that is 5 feet in diameter and 10 feet long would contain
> approximately 196 cubic feet of air.  196/3=65.3 cubic feet  196/5=39.2 cubic
> feet.  Based on the numbers a single fan with 61cfm should do the job. 
> Although personally I would use two smaller fans, this gives me some
> redundancy incase one fan were to fail
> 
> Roger June