A gallery of home built hoods and fume scrubbers _hood_

[Yggdrasil]

Sorry for replying you late, Yggdrasil
Obviously, we can see that the working space there is no safety at all. You wouldnt imagine that when they pour to mix AR, the acid spilled a lot on the floor; and the workers there told me they got acquainted with breath in the fume whenever they do refining once a month . And they were just few of the bad things i mention here.
By the way, i noticed that you regarded to an oversized scrubbing system, so could you please give me any hints about this setup?

How about applying the setup with double - packing tower srubber (each tower : 12" pipe x 8' height, filled with bio balls and a spiral nozzle on top of) ? If it is possible, do I need any further calculations for the exhaust fan?

See 4metals comment/reply please.

 

[J.Najam]

Helllo again,

I wanted to confirm if using this light inside the hood would be OK? Although the bar marked in green is made from PVC but the one marked in red is more of an exposure where the leads connect to the light. I was thinking of sealing it off using a glue gun but again what should be used for the wires? Would teflon tape be sufficient? or would I need something else to use as a protection.

Thanks for your time in advance

 

[4metals]

Keeping as short a length of wire in the hood as possible is best and a bit of silicone on the metal parts is a necessity. You could also cut out a rectangle in the top of the hood, glue on a piece of plexiglass, and put the light on top of the hood and you don’t need to worry about it.

 

[J.Najam]

You could also cut out a rectangle in the top of the hood, glue on a piece of plexiglass, and put the light on top of the hood and you don’t need to worry about it.

This would have been perfect but im short of the equipment required to do so.

On the other hand if I was to stick it onto one of the walls using a double side stick ons, would they work fine given we secure the exposed areas of the stick ons or both the complete sides with the silicone as well?

 

[Yggdrasil]

This would have been perfect but im short of the equipment required to do so.

On the other hand if I was to stick it onto one of the walls using a double side stick ons, would they work fine given we secure the exposed areas of the stick ons or both the complete sides with the silicone as well?

Cut a small opening.
Put in some glass and let the light be on the outside.

 

[mr.data]

Fairly large fume hood 140x120x60 cm. Stole the layout design from a fume hood I bought and rebuild with my own wood working skills.
The first motor was way to small because the smoke turned right back down and out. The second motor sucks about 300 l/h but it's still not 100% right

 

[didit]

Finally completed my DIY fume hood.

Interior measurement: 39.75 W x 34.25 H x 30 Deep
Inline fan: 12 inch fan with 1060 cfm output
PVC pipe - 4 inch pipe with 2 inch constriction

Hood and table top are made of Melamine (no wood or metal is inside the hood with the exception of some staples which are coated with 'Flex Seal'- trim pieces and baffle are made of PVC trim and paneling)

Long black mark in the center of the wye is where the 2 inch pipe ends. I originally had it at the arrow but found it better at the long mark point after re-testing with a meter. I think though anywhere between those two points would be fine.

I can try and get the cost of the hood but it took awhile because I spent months waiting for good deals and sales. I also went a little overboard on the building the table. It has a pull out table surface and a pull out trash can for 'sweeps'.

Hope this helps other DIYer's.

 

[jaywhiz85]

The hood with the scrubber alongside in the first photo is the way old school fume scrubbing worked. 100% of the fume went through the scrubber for scrubbing. The issue was to get sufficient flow for good exhaust, the scrubber needed to be huge to give them the retention time needed for good scrubbing. So the trade off was less flow overall (which causes the corrosion in the facility that Ygg was describing not to mention the effect on the workers) or inefficient scrubbing because the fume can't stay in the scrubber long enough.
What we propose is a general exhaust to get the hood to move enough air for worker safety and a fume scrubber to selectively pick up the majority of the nasty fumes over the reaction itself. So this requires a hood exhausted directly out of the workspace. Typically upward above the roof height. And a scrubbed exhaust, also exiting above the work space.

when you says scrubbed exhaust exiting the work place. are we talking about a carbon filter or something like that? I'm having a hard time finding something to hook up to a fan and ducting system that has an intake and exhaust.

 

[Yggdrasil]

when you says scrubbed exhaust exiting the work place. are we talking about a carbon filter or something like that? I'm having a hard time finding something to hook up to a fan and ducting system that has an intake and exhaust.

There are multiple discussions in here regarding scrubber and No Carbon filter is not a scrubber.
We are talking abou tank(s) that has the capacity to let all the gases from the hood contact enough liquid to remove all the harmful gases.
Go into building your own equipment and read.

 

[J.Najam]

Hello,

Long time coming I think Im almost done here.. if there is something that Im missing I would love to know.

The cut pvc in the bucket, I will use as the packing for the scurbbing cylinders.

Also I decided to use these cups in the last image for the bottom of my cylinders, in order to not let the packing clog the opening of the valve. It has holes in it to let the air travel, i did some test runs and the airflow seems fine but I did notice that some bubbles stay in there even after shutting off the pump. When I shake the cylinders I feel some movement inside of it like a tell that some bubbles just left the cup. So let me know of it still is OK to carry on?

Many thanks for your time again.

 

[J.Najam]

Cut a small opening.
Put in some glass and let the light be on the outside.

Yep. Done

 

[4metals]

Please, Stand back a bit and take a photo so we can see the perspective of the hood and the scrubber.

 

[J.Najam]

Please, Stand back a bit and take a photo so we can see the perspective of the hood and the scrubber.

Alright, ill try my best to make it easy. Unfortunately the lane is very narrow so this is as far as I can take. But I'll take different shots

 

[Yggdrasil]

Hello,

Long time coming I think Im almost done here.. if there is something that Im missing I would love to know.

The cut pvc in the bucket, I will use as the packing for the scurbbing cylinders.

Also I decided to use these cups in the last image for the bottom of my cylinders, in order to not let the packing clog the opening of the valve. It has holes in it to let the air travel, i did some test runs and the airflow seems fine but I did notice that some bubbles stay in there even after shutting off the pump. When I shake the cylinders I feel some movement inside of it like a tell that some bubbles just left the cup. So let me know of it still is OK to carry on?

Many thanks for your time again.

Hmm.
What system are you using here?
Vacuum or flow through?

 

[J.Najam]

Well I got some new clicks here, this is the best I could do in the space I have.

1 and 2nd picture is the perspective of my fumehood. The chair there is referential to the space between the hood and the wall.

3rd, the fumehood itself.

4th and 5th the scrubbing system

6th the issue : i noticed the wall has cracks and initially I planned on getting the exhaust pipe next to the other two. But since there seems to be danger so now im thinking of creating a loop around the whole cabinet. I may have to insert an extra blower midway to ensure the air throw is proper out the exit.

I would also like a suggestion on the position of the exhaust fan. I ran a couple of tests and it seems like the fumes are being drawn from under the funnel too. I used a cigarette, stuck it in ash tray and placed it inside the beaker and covered it with a watchglass. The emissions were barely going up the funnel and more in the fan. Although it will be tough to get carve another hole manually, but if need be I ll do it. So let me know if it will be needed or there can be another way.

Hmm.
What system are you using here?
Vacuum or flow through?

Im using the vacuum system here. What would be flow through again sorry?

Many thanks for your time again.

 

[Yggdrasil]

Well I got some new clicks here, this is the best I could do in the space I have.

1 and 2nd picture is the perspective of my fumehood. The chair there is referential to the space between the hood and the wall.

3rd, the fumehood itself.

4th and 5th the scrubbing system

6th the issue : i noticed the wall has cracks and initially I planned on getting the exhaust pipe next to the other two. But since there seems to be danger so now im thinking of creating a loop around the whole cabinet. I may have to insert an extra blower midway to ensure the air throw is proper out the exit.

I would also like a suggestion on the position of the exhaust fan. I ran a couple of tests and it seems like the fumes are being drawn from under the funnel too. I used a cigarette, stuck it in ash tray and placed it inside the beaker and covered it with a watchglass. The emissions were barely going up the funnel and more in the fan. Although it will be tough to get carve another hole manually, but if need be I ll do it. So let me know if it will be needed or there can be another way.


Im using the vacuum system here. What would be flow through again sorry?

Many thanks for your time again.

For a vacuum system there is not much need of packing's.
Only liquid and since you have 5 cylinders there is plenty of retention time.
Flow through, is where you put all your air from the hood through scrubbers with packing.
If there is not enough vacuum the air/fumes from the reaction vessel will not be dragged through the funnel.
How much vacuum do you have?
Maybe you need to bypass two of your cylinders?

 

[J.Najam]

For a vacuum system there is not much need of packing's.

With due respect, I guess I may have mentioned it earlier that Ill be using a vacuum pump for suction and the packing discussion followed...

Only liquid and since you have 5 cylinders there is plenty of retention time.

This sounds as a relief

Flow through, is where you put all your air from the hood through scrubbers with packing.

got it maybe in the future

If there is not enough vacuum the air/fumes from the reaction vessel will not be dragged through the funnel.

i have done many tests without the presence of the fan. The fumes were being dragged in through the funnel just fine. But now when everything is put together, the fan just seems to be an overkill. Im doubting it is probably its position in the hood is all.

Maybe switch it off when undergoing the regular vacuum suction operation. Would that be safe enough?

Maybe you need to bypass two of your cylinders?

3 tall ones are regular and will be filled with NaOH. The smaller glass bottle is for the backflow and the taller one is basically a tell for the vacuum strength. Since each has their own purpose, I wouldn't want to disturb it

Thanks for your time

 

[J.Najam]

Hello again,

So my dad wont lend me his cigarettes anymore for these tests as they were all being wasted. So I tried again today with boiling water as another test. I wish Id taken some clicks but Id like some clarification as per my observations :

1, the fumes tend to condense and form drops around the inside ring of the funnel and they then drop onto the hotplate. What is suggested to combat this concern?

2, the vacuum started to function alright. The glass bottles were a great tell as initially the bottles had some smoke coming in and then it started to condense into vapours. However, I noticed considerable emissions from the funnel, are they supposed to go upstream into the funnel too or should I just make peace with it and move on? Like both things are happening, the vacuum is pulling it but there are noticeable emissions too.

Many thanks for your time again

 

[Yggdrasil]

Hello again,

So my dad wont lend me his cigarettes anymore for these tests as they were all being wasted. So I tried again today with boiling water as another test. I wish Id taken some clicks but Id like some clarification as per my observations :

1, the fumes tend to condense and form drops around the inside ring of the funnel and they then drop onto the hotplate. What is suggested to combat this concern?

2, the vacuum started to function alright. The glass bottles were a great tell as initially the bottles had some smoke coming in and then it started to condense into vapours. However, I noticed considerable emissions from the funnel, are they supposed to go upstream into the funnel too or should I just make peace with it and move on? Like both things are happening, the vacuum is pulling it but there are noticeable emissions too.

Many thanks for your time again

If your vacuum is correct all the fumes should go through your flask train

 

[tsfarley]

I decided to start the 2nd half of my ewaste hobby by building a small vented hood.
I had 4 or 5 of the old black table tops (1950's) from a school chem lab, so those limit my depth to about 24inches (61cm). I also found some 1/4 inch plexiglass extremely cheap which was 24in wide also, so that is working.

I wanted to be able see in the sides, so those are plexiglass also. For the front, I just plan to have a plexi panel slide up and down in a small channel.

The back is plain 5/8 plywood as well as the back half (12in) of the top. The front will be plexiglass also.
The end size will be about 24in deep, 32 in wide, 30 in high.
Top will have a 4" pvc duct feeding out to the back of the barn. I'm still laying out the venturi vacuum plans. (yes, I'll be reviewing all GRF posts for that. )
I'm considering a backup fan system at the end of the line outside in case the venturi system fails during operation.
something like flip a switch and the 2ndary fans come on while opening a 2nd exit port outside. soon I will start on a fume cleaning system for outside.

it's been fun collecting pins, chips, cpus, boards, ram, etc. but I really don't have a clue on what it may be worth down the road; so here goes nothing!

I had just planned on caulking the seams and corners. Is any caulking best for acid fume environment?

Should I paint all the wood with something special?
Has anybody found that they just really need 36 or 48" wide hoods and smaller is a pain?
I'll finish this one and start on a 2nd larger one later; first I need to finish up a small ADU for my daughter (background of pics).
Being retired is excellent.
feedback, criticism is welcome.
more pics to follow as I progress.
Tim