What Filter For Diy Flowhood

Laminar Menses Hood - Build a HEPA filter flowhood

( updated: June xv, 2021, at 06:54 AM )
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Tabular array of contents

Why yous demand one
Getting started
Sources for HEPA filters
Match a blower to the filter
Find the correct blower
Construction of the hood
More pictures

Why you need one

A laminar menstruation hood is a slice of equipment which makes sterile working procedures in mushroom cultivation easier and reliable.

A flow hood consists of a fibroid pre-filter, a blower and a very fine filter (the then chosen HEPA (High Efficiency Particulate Air) filter which filters particles from the air to a high caste.

This makes the air coming out of the HEPA filter nearly sterile which allows doing transfers in this stream of sterile air without worrying well-nigh contaminants entering from the air and contaminating the cultures.

Getting started

You should brainstorm the construction by selecting a HEPA filter and a blower.

The HEPA filter size depends on how big you want to have your working space. The smallest filter size you lot tin reasonably use (for home calibration tillage) is 1ft ten 1ft, ameliorate though 1ft 10 2ft or 2ft ten 2ft if you are going to inoculate filter bags.

Sources for HEPA filters

Ebay offers

Worldwide sources

www.aafeurope.com
(Austria, Belgium, Bosnia & Hercegovina, Bulgaria, Canada, Communist china, Republic of croatia, Czech republic, Republic of finland, France, Federal republic of germany, Dandy United kingdom & Eire, Greece, Hungary, India, Italy, Luxembourg, Malaysia, United mexican states, Heart-Due east, Netherlands, Kingdom of saudi arabia, Serbia, Singapore, Slovakia, Slovenia, South Africa, Spain, Taiwan, Turkey, United Arab Emirates (UAE), The states)

www.camfil.com
(Australia, Austria, Belgium, Brasil, Canada, China, Danmark, Deutschland, España, France, Republic of ireland, Italia, Malaysia, Netherlands, New Zealand, Polska, Schweiz, Singapore, Suomi, Sverige, United Kingdom, The states)

Country specific sources

Australia

world wide web.aesenvironmental.com.au

Austria

world wide web.czech.at
airfiltration.isle of mann-hummel.com

Canada

bgecleanair.com

France

world wide web.aaf-sa.fr
www.climavent.fr

Federal republic of germany

www.aaf-lufttechnik.de
world wide web.atex-filter.de
www.camfil.de
world wide web.cleanroom.de
world wide web.luftfilterbau.de
www.euro-filter.de
world wide web.filtega.de
www.het-filter.de
www.reinraum.de
world wide web.spxairfiltration.eu
www.wieninger-filter.de

Filtertechnik-Germany

Bharat

www.aeromechindia.com
www.multilab.biz

Israel

world wide web.filt-air.com

Italy

world wide web.altifilter.com
www.defil.it
www.eurofiltri.com
www.fcr.it
www.ma-in.com
www.mcleodrussel.it

http://www.google.it/search?q=filtri+assoluti

Netherlands

www.mcleodrussel.nl

Norway

www.aafluftfilter.no

Russia

www.enveron.ru
world wide web.ftov.ru

Slovenia

www.ecotip.si
www.hidria-imp-klima.si

Sweden

www.scandfilter.se

Switzerland

www.logicair.ch
www.sit down.ch
www.tecnofil.ch
www.unifil.ch
world wide web.vokes-air.ch
www.trion-elektrofilter.ch (details)
www.wesco.ch (details)

Turkey

www.aaf.com.tr
www.boytem.net
www.tekfil.com

United Kingdom (Britain)

www.hepa.co.uk

USA

www.aafilters.com
world wide web.airexco.com
www.airflotek.com
world wide web.appliedairtechnology.com
www.cambridgefilterusa.com
www.cepatest.com
www.filtera-b2b.com
www.filterservicesil.com
world wide web.fungi.com
world wide web.hepa.com
www.hepafilters.com
www.laminaire.com
www.lascoservices.com
www.techrite.com
www.tridim.com

The states Filter search web site

Yugoslavia

world wide web.interfilter.co.yu

Match a blower to the filter

Once you decided on the size of the HEPA filter, you take to match a suitable blower to this detail filter. This is a very important stride, so brand certain to report the directions thoroughly.

Every filter has a "resistance" when air blows through it at a certain speed, this resistance is called the "static pressure".

Printing your hand against your mouth. At present try to accident through information technology. Dependant on how firm you press information technology against your oral cavity, you lot will take some difficulties bravado air out and you will feel some resistance, this is the static pressure level.

Every filter has a dissimilar static pressure at the working signal. The working indicate is where the corporeality of the air flowing through the filter is sufficient to meet the requirement of the laminar catamenia.

The static pressure is expressed in inch of water column in the English units, a typical value would be 1", the SI unit for force per unit area is Pa(Pascal).

1" water column is around 250 Pa. Each filter has a information sheet (consult the manufacturer if this is not the case with your filter) where the static pressure level at the working point is entered. Before the air enters the blower information technology is usually pre-filtered by a furnace filter around i"(2.5cm) thick placed in front of the blower to protect it and the HEPA filter from large particles like dust and hairs. It can be causeless that the static pressure for this prefilter at the working point is effectually 0.2"(50 Pa)

According to Stamets (Paul Stamets and J.S.Chilton: The Mushroom Cultivator p. 347 ff) the air speed of the air flowing from the filter surface should be (at least) 100 feet per minute(fpm).(effectually 30 meter per minute or 0.5 meter per 2nd). Determining the correct blower for a filter consists of several steps:

1. Find out the expanse of your filter by multiplying the width and the hight in feet (for example the smallest reasonably usable filter would be 2ft x 1ft)

2ft ten 1ft = 2 ft²

two. Multiply the required air speed(the one Stamets specifies, 100 ft/min) with the surface area of your filter

100 ft/min 10 ii ft² = 200 ftⁱⁱⁱ/min

And then 200 ftⁱⁱⁱ/min(= cfm = "cubic anxiety per infinitesimal") is the amount of air your blower must deliver at the sum of the STATIC PRESSURE of the HEPA filter + prefilter.

Notation: one cfm= 1.7mⁱⁱⁱ/h

So if you use the in a higher place filter with one"(250Pa) static pressure and a furnace prefilter with a static pressure of 0.2"(50Pa) your blower must deliver 200 cfm(340m^three/h) of air at a static pressure of 1.ii"(300Pa).

Finding the correct blower

Each blower has a information sheet (consult the manufacturer if this is not the case with your blower) where the correlation between the volumetric flow and the static pressure is represented by a graph or table.

Here is such a fix of curves for 4 blowers(numbered 1-iv).
NOTE: Each model of a blower has his own feature curve. This chart shows the curves for four different particular models of centric duct blowers.
What y'all tin can clearly see is that the bigger the static pressure the less air the blower delivers, up to the maximum static pressure where the air output is zero.

Sometimes these data are presented in grade of a table.

By now you know how much your blower must deliver and at which static pressure level. In our example it was 340mⁱⁱⁱ/h at 300Pa.
And so what we do now is to go in this chart and observe the value of 300Pa(=1.2") at the vertical axis. And so you motility to the correct until you attain 340mⁱⁱⁱ/h.(=200cfm)
Now, ideally there should exist a bend of a blower going exactly trough this point, only this is not always the case.
So nosotros take to choose a blower that best approximates our requirements.
In well-nigh cases we should choose a stronger blower, if it'southward non too stiff.
How strong is too strong? I'd say the blower shouldn't deliver more than that xx% more air than we calculated, then in our case the strongest acceptable blower would be around 400m³/h.
In this example we take a blower that delivers 300m³/h(according to our calculation it should evangelize 340mⁱⁱⁱ/h though). This is a difference of mere 10%. The adjacent stronger blower in this chart delivers 530mⁱⁱⁱ/h at 300Pa, which is way too much.

In this case we go for the smaller(and cheaper) blower(Nr.4) instead of the much bigger one(Nr.i, which delivers 530m³/h at 300Pa), despite the fact that it'due south generally recommended to take a stronger one.

Annotation: This chart is only an example for a set of iv particular blowers. The curves of the blowers available to you may look a bit dissimilar, but similar.
Usually, if you search long enough, you will exist able to find a blower that exactly matches your HEPA.

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

You tin get many blowers at ebay.com, often at much cheaper prices than if you bought them directly.

Ebay offers

It is of import to contact the seller in advance and inquire near the exact characteristics of the blower beforehand, and then y'all don't finish up with a also weak blower.

When in doubt, head for the more than powerful blower, you can even so regulate it down if necessary with a variable speed controller/regulator:

Ebay offers

Construction of the hood

Afterwards you bought the HEPA filter and a matching blower , you take to get some materials for the construction of the box that will accommodate the in a higher place two components. Basically you want to build a box, the forepart wall of the box volition consist of the HEPA filter, and another wall will take the inlet of the blower with the pre-filter mounted. I had the material for the walls already cutting to fit the size of the filter and the blower. I begin by gluing and screwing the filter to the bottom wall.
And then I add the side walls....
....and the dorsum wall.
The blower will be mounted and then the inlet is at the acme.
A hole is cut in the wall at the top to accommodate the blower inlet.
The blower rests on a bar mounted in the box. The white dots on the bar is some(already dried) silicone mass to provide some damping and lessens vibrations. All the joints are filled with silicone mass so the box is airtight.
The elevation with the blower is screwed on the box. The space around the opening and all other cracks in the box are tightened with silicone mass.
A pre filter is mounted atop of the blower. I utilise a furnace filter, you can also employ other filers, similar car air filters, just make sure they are large enough and that they don't have likewise much air resistance, otherwise you would need a larger blower.
Detail of the pre-filter.
A net is tackered to the frame of the HEPA filter to prevent touching and harming the frail filter.
The finished menstruum hood.
Some pictures of a similar pattern, the merely difference is that the blower is mounted around x cm deeper, so the pre filer is in the same level every bit the residuum of the box. Makes information technology more visually appealing and more than compact this way. Yet more pictures of the design on the correct tin can exist constitute in the gallery