A gallery of home built hoods and fume scrubbers _hood_

[4metals]

3, 'The blue line is vacuum and is selected at the valve by the vacuum generator. Each 1/2" vacuum port needs a shut off valve and a PVC barbed fitting.' I really don't understand if this would be needed... I would be highly grateful for your response as I'm brain cooked at this point of trying to make this thing work properly.

The blue line is to use the same vacuum source to pull suction for filtration and solution transfer. The valves are needed to separate the vacuum going to the scrubber from the vacuum going to the filtration suction line (blue). They cannot be used at the same time because the vacuum is not strong enough to supply adequate CFM for both. Similarly but not shown, shut off valves should be on the blue pipe that runs through the hood where little blue circles indicate ports to install suction shut off valves. If you are using the system for filtration having one suction port in use and the other open will result in no vacuum as the vacuum air takes the path of least resistance . That is why we need valves.

 

[Yggdrasil]

Hello sir,

My mind this past week had been so clogged that I completely missed this one and now I think this is probably the closest of how I can imagine my setup to be like given what I have already built.

I do have questions here :

1, The overhead blower does not seem to be connected to the red pipes, so what is its main purposes here? the regular fumes of the hood only?
2, The red pipe does not have any suction or blowing therein as can be seen, so is the science of the entire unit being taken care of by that lone pump at the bottom right end only?
3, 'The blue line is vacuum and is selected at the valve by the vacuum generator. Each 1/2" vacuum port needs a shut off valve and a PVC barbed fitting.' I really don't understand if this would be needed... I would be highly grateful for your response as I'm brain cooked at this point of trying to make this thing work properly.

Many thanks in advance.

To simplify 4metals answer.
Both the red and the blue line is vacuum lines and the colomns are the flask train.

 

[4metals]

I have edited the image to include the vacuum system working to filter a solution. Please keep in mind it can be one or the other, scrub fumes or filter solutions. Open and close valves accordingly.

 

[J.Najam]

The overhead pipe (black in the drawing) is for what the EPA refers to as fugitive emission, it is separate from the scrubbed emission which is indicated with the red pipes.

Oh okay

The red pipe is powered by a venturi (actually a water powered venturi also called an eductor). The eductor is powered by the pump which recirculates water through the eductor to generate suction which transferred into the red pipe.

I think I now understand the concept of an eductor for vacuum generation. I really had no idea how it works, although its late here, but I'll just be on my way to carry a baby experiment with a water pump I have to fully grasp the concept.

Both the red and the blue line is vacuum lines and the colomns are the flask train.

Ah yes but if I understood it correctly both these pipes are obviously for different purposes. While the red goes to the scrubbers, the blue is an extension of the scrubbing unit in terms of only using its vacuum for filtration. But this one I think will be challenging for a novice in my situation so Ill just use a regular gas suction pump that I have. They're not non-corrosive but they're cheap so Ill just keep buying once they're about to die down. Their sound of the coil and machine is a tell. I've used these a lot for past filtrations.

I have edited the image to include the vacuum system working to filter a solution. Please keep in mind it can be one or the other, scrub fumes or filter solutions. Open and close valves accordingly.

Really appreciate it sir! I cant thank all of you enough.

On the other hand, looking at my own setup. I'm thinking 2 possibilities :

1, replace the 3inch pipe of the blower and use a 1 or 2 inch pipe with openings for suction in a closed system with a pvc tube flask train as as shown in these diagrams above.

2, build a scrubber with buckets using the same setup as blower from the left with a venturi into the fumehood as it already is and then lower the pipe into bucket trains as well as eductor suction from the other end?