Flowhood pictorial

From www.fungifun.com


A flow hood is a very useful piece of equipment which makes sterile work in mushroom cultivation easyer and more reliable.
Basicaly it consists of a coarse pre-filter, a blower and a very fine filter (the so called HEPA(High Efficiency Particulate Air) filter which filters particles from air to a degree that the air coming out of the HEPA filter is nearly sterile.
One can then work in this stream of air without worrying about contaminants entering from the air and contaminating the cultures.

Some sources for hepa filters:

U S A :

G e r m a n y :

U K :

A u s t r i a :


You should begin the construction by selecting a filter and a blower.
The filter size depends on how big you want to have your working space. The smallest filter size you can reasaonably use (for home scale cultivation) is 1 ft X 1 ft, better though 1ft x 2ft. The filter on the right is a 1 ft x 1 ft HEPA with 99.995% removal efficiency for particles down to 0.3 micron.

When you decide on the filter, you have to match a suitable blower to this particular filter.

A possible combination would be:

this blower with

this filter
Part Number: HSP924125
Actual Size (HxWxD): 24x12x5-7/8
Rated Airflow (SCFM): 300
Initial Resistance ("w.g.): 1.0

You should mount a good, thick prefilter(furnace filter), since this blower is a bit overpowered.

The design in the pictorial uses an in-line centrifugal fan, another good option (actually the one most used for flow hoods) is a squirrel cage blower (also called shaded pole blower).