Difference between revisions of "Project:Flow Hood"

From London Hackspace Wiki
Jump to navigation Jump to search
(Created page with "== Overview == A [http://en.wikipedia.org/wiki/Laminar_flow_hood Laminar Flow Hood] would enable us to greatly improve the aseptic technique protocol in the hackspace. But fi...")
 
m (Reverted edits by Tolland (talk) to last revision by Czechton)
 
(16 intermediate revisions by 2 users not shown)
Line 10: Line 10:
  
 
[[File:Verticalhood.jpg]]
 
[[File:Verticalhood.jpg]]
 +
 +
Proposed vertical hood design:
 +
 +
[[File:VerticalhoodSketchup.png]]
 +
 +
[https://www.dropbox.com/s/pbyrjrmhtqgbdi3/steel%20box%20section.skp SketchUp file of proposed design]
  
 
== Construction and Materials ==
 
== Construction and Materials ==
−
== Frame ==
+
=== Frame ===
 
We need to construct a frame: perhaps weld together some steel box section; or chop up and repurpose an old shelving unit; or construct it out of [http://www.makerbeam.eu/ makerbeam], [http://www.technobotsonline.com/construction-kits/openbeam.html openbeam] or [http://www.aluminiumwarehouse.co.uk/EasyFix_Tube_Connectors/c180/index.html easy fix].
 
We need to construct a frame: perhaps weld together some steel box section; or chop up and repurpose an old shelving unit; or construct it out of [http://www.makerbeam.eu/ makerbeam], [http://www.technobotsonline.com/construction-kits/openbeam.html openbeam] or [http://www.aluminiumwarehouse.co.uk/EasyFix_Tube_Connectors/c180/index.html easy fix].
  
−
== Work surface and side panels ==
+
=== Work surface and side panels ===
−
Because we will be using 70% ethanol for sterilisation, the materials used for the sides and work surface must be resistant to this. Unfortunately 70% ethanol kills perspex over time so it looks like we will need to use glass for the sides and perhaps a sheet of stainless steel for the work surface.
+
Because we will be using 70% ethanol for sterilisation, the materials used for the sides and work surface must be resistant to this. Unfortunately 70% ethanol kills perspex over time so we should use glass for the sides and a sheet of polypropylene for the work surface.
 +
 
 +
=== Sealant ===
 +
The inside edges of the flow hood need to be sealed and air tight. As with the side panels, the sealant must be resistant to 70% ethanol, so ordinary bathroom sealant is out. So far the only ethanol resistant sealant I have found is [http://www.ppg.com/coatings/aerospace/sealants/indsealadh/Pages/default.aspx PRC Rapid Seal] which is rather expensive. A much cheaper alternative that may work is simply sticking PTFE tape along the edges. However the ethanol may work its way under the tape and cause the adhesive to loosen.
 +
 
 +
=== Filters ===
 +
HEPA rated filters will remove any bacteria and other contaminants from a flow of air. They are often used in air conditioners and air purifiers. The entire 'ceiling' of the flow hood must consist of filters, so the dimensions of worksurface of the hood are constrained by what size filters we can find for a reasonable price. <strike> So far [http://www.amazon.co.uk/Fellowes-Filter-Large-Purifier-9370101/dp/B0067D7D1S these filters on Amazon] appear to be our best option - we can put two next to each other to achieve a 64x42cm work surface. So far I have had no luck in getting the pressure drop information about the filters from Fellowes, an alternative is to use [https://secure.jfilters.com/v2/Store/Store.aspx?OptionID=10288&OptionItemID=11348&View=Filter this costlier filter (UMPW78132418)] from a company that will be able to provide detailed information </strike>
 +
 
 +
After finally discovering the specs of the Fellowes filters, they're not appropriate. That means we need to opt for the [http://www.jasunfiltration.com/acatalog/Jasun_Envirocare_plc_Grade_H13_256.html UMPW78 18x24] ([http://jasunfiltration.com/acatalog/datasheets/umpw78.pdf spec sheet]).
 +
 
 +
=== Blower/Fan ===
 +
We need to find a blower that will blow the right amount of air through the filters to create laminar flow. Instructions on how to figure out the maths of achieving laminar flow through a HEPA filter can be found in [http://fradnai.free.fr/docs/doc23.pdf this helpful PDF].
 +
 
 +
In our case:
 +
 
 +
To achieve 0.45m/s: airflow of 421m^3/h (248CFM)
 +
Filter pressure drop : 90Pa
 +
 
 +
The [http://db.sanyodenki.co.jp/product_db_e/coolingfan/dcfan/dc_fan_detail.php?master_id=2527 Sanyo Denki 9GV1512H501] should be able to handle this though we may need to bump it to 13V or so.
 +
 
 +
=== Shopping List ===
 +
{| class="wikitable"
 +
!Item
 +
!Amount
 +
!Cost
 +
|-
 +
| [http://www.metals4u.co.uk/aluminium-angle/1-x-34-x-18/12/8697/detail.asp Aluminium Angle]<br/>1" x 3/4" x 1/8" || 5000mm || £14.00
 +
|-
 +
| [http://www.metals4u.co.uk/aluminium-angle/38-x-38-x-116/12/8695/detail.asp Aluminium Angle]<br/>3/8" x 3/8" x 1/16" || 1000mm || £1.17
 +
|-
 +
| [http://www.metals4u.co.uk/mild-steel-box-section/1-x-1-x-14swg-mild-steel-box/49/2383/detail.asp Mild Steel Box]<br/>1" x 1" x 14swg || 2x6000mm || £39.70
 +
|-
 +
| [http://www.directplasticsonline.co.uk/PolypropyleneSheet/1mm/ Polypropylene Sheet]<br/>1000 x 500 x 1mm || 1 || £4.85
 +
|-
 +
| [http://www.directplasticsonline.co.uk/PolypropyleneSheet/1mm/ Polypropylene Sheet]<br/>1000 x 1000 x 1mm || 1 || £9.24
 +
|-
 +
| [http://www.jasunfiltration.com/acatalog/Jasun_Envirocare_plc_Grade_H13_256.html Ultima MPW78 18x24] || 1 || £100.00
 +
|-
 +
| Glass<br/>450 x 800 x 3mm || 2 || £...
 +
|-
 +
| Glass<br/>603 x 550 x 3mm || 1 || £...
 +
|-
 +
| [http://uk.mouser.com/ProductDetail/Sanyo-Denki/9GV1512H501/?qs=sGAEpiMZZMtmglTKXDHoWiEX1mLPmXqu1%252bkk5Gft5iQ%3d Sanyo-Denki 9GV1512H501] || 1 || £26.25
 +
|}
 +
 
 +
== Links ==
 +
[http://myco-tek.org/showthread.php?49-EvilMushroom666-s-Flowhood-Build http://myco-tek.org/showthread.php?49-EvilMushroom666-s-Flowhood-Build]
 +
 
 +
[http://edgeqld.org.au/catalyst/2013/01/03/diy-laminar-flow-hood/ http://edgeqld.org.au/catalyst/2013/01/03/diy-laminar-flow-hood/]
 +
 
 +
 
  
−
== Filters ==
+
[[Category:Biohacking]]
−
HEPA rated filters will remove any bacteria and other contaminants from a flow of air. They are often used in air conditioners and air purifiers. The entire 'ceiling' of the flow hood must consist of filters, so the dimensions of worksurface of the hood are constrained by what size filters we can find for a reasonable price. So far [http://www.amazon.co.uk/Fellowes-Filter-Large-Purifier-9370101/dp/B0067D7D1S these filters on Amazon] appear to be our best option - we can put two next to each other to achieve a 64x42cm work surface.
 

Latest revision as of 10:17, 10 August 2014

Overview

A Laminar Flow Hood would enable us to greatly improve the aseptic technique protocol in the hackspace. But first we need to make one.

Basic design

We should aim to build a vertical flow hood as that not only protects cultures from contamination but protects the user from the cultures being worked on.

Here is a basic diagram of what it should look like.

Verticalhood.jpg

Proposed vertical hood design:

VerticalhoodSketchup.png

SketchUp file of proposed design

Construction and Materials

Frame

We need to construct a frame: perhaps weld together some steel box section; or chop up and repurpose an old shelving unit; or construct it out of makerbeam, openbeam or easy fix.

Work surface and side panels

Because we will be using 70% ethanol for sterilisation, the materials used for the sides and work surface must be resistant to this. Unfortunately 70% ethanol kills perspex over time so we should use glass for the sides and a sheet of polypropylene for the work surface.

Sealant

The inside edges of the flow hood need to be sealed and air tight. As with the side panels, the sealant must be resistant to 70% ethanol, so ordinary bathroom sealant is out. So far the only ethanol resistant sealant I have found is PRC Rapid Seal which is rather expensive. A much cheaper alternative that may work is simply sticking PTFE tape along the edges. However the ethanol may work its way under the tape and cause the adhesive to loosen.

Filters

HEPA rated filters will remove any bacteria and other contaminants from a flow of air. They are often used in air conditioners and air purifiers. The entire 'ceiling' of the flow hood must consist of filters, so the dimensions of worksurface of the hood are constrained by what size filters we can find for a reasonable price. So far these filters on Amazon appear to be our best option - we can put two next to each other to achieve a 64x42cm work surface. So far I have had no luck in getting the pressure drop information about the filters from Fellowes, an alternative is to use this costlier filter (UMPW78132418) from a company that will be able to provide detailed information

After finally discovering the specs of the Fellowes filters, they're not appropriate. That means we need to opt for the UMPW78 18x24 (spec sheet).

Blower/Fan

We need to find a blower that will blow the right amount of air through the filters to create laminar flow. Instructions on how to figure out the maths of achieving laminar flow through a HEPA filter can be found in this helpful PDF.

In our case: 

To achieve 0.45m/s: airflow of 421m^3/h (248CFM) 
Filter pressure drop : 90Pa

The Sanyo Denki 9GV1512H501 should be able to handle this though we may need to bump it to 13V or so.

Shopping List

Item Amount Cost
Aluminium Angle
1" x 3/4" x 1/8"		 5000mm £14.00
Aluminium Angle
3/8" x 3/8" x 1/16"		 1000mm £1.17
Mild Steel Box
1" x 1" x 14swg		 2x6000mm £39.70
Polypropylene Sheet
1000 x 500 x 1mm		 1 £4.85
Polypropylene Sheet
1000 x 1000 x 1mm		 1 £9.24
Ultima MPW78 18x24 1 £100.00
Glass
450 x 800 x 3mm		 2 £...
Glass
603 x 550 x 3mm		 1 £...
Sanyo-Denki 9GV1512H501 1 £26.25

Links

http://myco-tek.org/showthread.php?49-EvilMushroom666-s-Flowhood-Build

http://edgeqld.org.au/catalyst/2013/01/03/diy-laminar-flow-hood/

Retrieved from ‘https://wiki.london.hackspace.org.uk/w/index.php?title=Project:Flow_Hood&oldid=42570’