Building a chemical fume hood with a plain steel blower

[4metals]

Whose hood is that with the scrubber cylinders in the red milk crate? Is this the system you are talking about or is this someone else's system?

I'm confused[emoji848]


Sent from my iPhone using Tapatalk

 

[saadat68]

Hi
4Metal
Can you check blow picture? The picture of first post is very small and I can't read all of numbers
Thanks

 

[4metals]

The blower is 500 CFM and the pipe coming out of the blower is 6"

The duct leaving the hood is 12". In the setup I used this hood it went straight up 20 feet through the roof.

The opening is 30" x 30"

The door covering the opening is 30" x 18" Leaving an opening of 12" x 30" when closed.

The bend upward from the blower inside the hood should not be a 90 degree elbow but a sweep. Sweeps get expensive so a pair of 45 degree elbows will suffice. There is too much flow lost in a standard 90 degree fitting, a long sweep is best, 4-22 1/2º fittings is next, 2-45º fittings next and last is a standard 90º fitting. The more air flows through the 6" pipe, the more air is sucked along with it up the 12" pipe. So if you are buying a blower opt for the highest CFM flow.

 

[saadat68]

Thanks for your nice and cheap design

 

[saadat68]

Hi
20 inch for deep is OK ?

 

[saadat68]

I have an idea :idea:
add blower under the hood. It can increase efficiency
Isn't better?

 

[saadat68]

4metals
Sorry
Can you help me ? I am confusing
As you said more CFM is better I want to add one 1000 CFM exhaust fan to my hood. Exhaust fan is cheaper than blower and it costs 35$

I can not find 12" pipe. which is better ?

Add 2 pipe (4.33") over the hood and 2 pipe (2.48") from blower
Add 1 pipe (4.33")over the hood and 1 pipe (3.54") from blower

I can find these pipes here:

4.99"
4.33"
3.54"
2.48"

 

[Barren Realms 007]

4metals
Sorry
Can you help me ? I am confusing
As you said more CFM is better I want to add one 1000 CFM exhaust fan to my hood. Exhaust fan is cheaper than blower and it costs 35$

I can not find 12" pipe. which is better ?

Add 2 pipe (4.33") over the hood and 2 pipe (2.48") from blower
Add 1 pipe (4.33")over the hood and 1 pipe (3.54") from blower

I can find these pipes here:

4.33"
3.54"
2.48"

Check in your country for a plumbing supply company they should have the pipe size you are wanting.

 

[saadat68]

Thanks for your reply
I searched in web. companies produce larger pipes here but I can not find in shops. Large pipes use in big projects. Largest size that I can buy is 4.92"
I think I must use 2 or 3 pipes instead of one

 

[saadat68]

OK
This is my design. Add 2 pipes 4.9" over the hood and add 2 pipes 3.54" from 700 CFM exhaust fan
20" deep and 23" * 12" opening
Tomorrow go to carpentry. Hope it works
I will post picture after finishing

 

[butcher]

creating a venturi, with different pipe sizes, will improve performance.

https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=venturi+effect

 

[saadat68]

Today I get my hood from carpenter
Now I must coat it with epoxy paint and add pipes and an exhaust fan for blowing air

 

[saadat68]

I buy this fan for 11$. It is 640 CFM
Can I use it instead of blower ?

 

[Palladium]

Though that fan may move air at a certain cfm rate it does so with really creating any resistance to the air or creating any vacuum. It blows 640 cfm with restrictions. Once you channel that air through pipes and turns it's going to lose it's pull or vacuum. You need a squirrel cage blower or centrifugal fan. Find you a scrap yard and get a blower from an old heating system if nothing else. I buy them for $20-50 depending on size. They are cheap and need replacing about every 2-3 years, but are cheap and easy to replace.

https://www.google.com/search?q=squirrel+cage+fan&num=30&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjmo5Pi8dHRAhVC4CYKHV4OCeAQ_AUICSgC&biw=1252&bih=582




.

 

[saadat68]

Finish! (90% completion )
Today I test my hood with fire some paper in the face of opening of the hood and I think it works 8) It sucks smokes

Thanks all specially 4metals

 

[saadat68]

image.jpg

This little scrubber handles everything passing the condensor of a 12 liter reaction flask just fine. It only has a 3 cfm flow rate from the eductor that powers it but in a sealed reaction that's plenty. The hood moves a lot of air, as Irons says to remove the whiffs of reagent while filling and emptying the equipment and make the environment for me in front of the hood better. It's all about me! :lol:

Hi
One year ago I made a scrubber like this with 3 of 5 liter erlenmeyer
But after 3 days I saw 2 of them were broken. They contain sodium hydroxide and I think it breaks my flasks
( I must say my erlens made from glass and not pyrex or etc )
Do you know what was my problem ?
Thanks

 

[4metals]

https://nvlpubs.nist.gov/nistpubs/jres/27/jresv27n2p143_A1b.pdf

I used the caustic sparingly only enough to maintain a slight alkalinity and never had any issues using Pyrex vacuum flasks.

 

[saadat68]

http://goldrefiningforum.com/~goldrefi/phpBB3/download/file.php?id=24799&t=1

I think white pipes is PVC
Can we use PP or PE pipes and connections instead of them ? ( I want learn to my countryman to how build scrubber but there is no pvc pipe like picture in my country )
Also we can use pvc hose but in some sections it is very better to use pipe
Thanks

 

[francisco rodriguez]

Hola a todos, empezando a fabricar el limpiador de gases, estaria correcto.?
Lo mas barato del mundo.
Gracias por sus criticas .

 

[francisco rodriguez]

Haber si soy capaz de enviar mas foto.?