# Fume Hood, Will it work?



## IntelGold (Apr 17, 2014)

Hi All, Not been on the forum for a while. I've been thinking of building a fume hood which will also act as a fume extractor for several buckets which will be used for AP. I would first like to say that it will only be used for HCL and Clorox Reactions, NO Nitric. Hopefully you can get the idea of what im trying to achieve.
Here's a very rough sketch of the proposed setup.
Any help would be Good.
Thanks.


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## nickvc (Apr 17, 2014)

I think I can see what your aiming for but your scrubber looks just like a reservoir which if I'm reading your sketch right won't work as there won't be enough pressure to push the fumes through it, for the scrubber to work you need it spraying the fumes with a mix of caustic, hydrogen peroxide and water over a large surface area and with enough time in the actual unit to scrub the fumes.
If you did your hcl bleach reactions in sealed conical beakers and piped the fumes through several more conical beakers the first with water the second with the mixture above it should do the job quite well, it won't remove all the fumes but the majority will be caught, a fume hood over the reactions venting the final fumes and then also scrubbed would finish the rest, if you intend to scrub your leach buckets with the same scrubber a valve to increase or decrease the flows from either area would be handy.


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## IntelGold (Apr 17, 2014)

Hi Nick, Thanks for the input. The scrubbing material was going to be marbles or activated carbon, maybe a mix of the two? This would allow air through unlike water. I only need to scrub it a little as I said only HCL is being used no Nitric. Cheers.


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## nickvc (Apr 17, 2014)

I might be wrong but I fear carbon won't last too long and will need regular changing, instead of marbles old plastic pipe cut into small rings might be cheaper and still give a large surface area but it will need to have the solution constantly running over it to scrub the fumes along with the fumes lingering in the scrubber so they can be scrubbed efficiently.
I still think that sealed reactions might well solve most of your problems with the chlorox reactions and easier to create, 4metals posted his system sometime back so do a search and see his drawings.
You might still need to vent the final fumes but a lot of the worse chemicals will be removed , for your AP reactions maybe some sort of condenser would help before venting off.


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## g_axelsson (Apr 17, 2014)

There are three drawbacks with placing the fan close to the hood and in front of the scrubber.
- If the filter gets too clogged the fan is going to create pressure in the hood and blow the gases out in the room instead of up the chimney.
- It will create a positive pressure in the scrubber with respect of the room, any leak will let out fumes in the room.
- The volume of air going through the scrubber is increased and the dwelling time is decreased, less scrubbing occur or you have to build a bigger scrubber.

If you place the eductor / fan in the end of the system you get a number of advantages.
- No matter how clogged the scrubber gets it will never blow fumes back
- You create lower pressure in the ducting and suction, any leak will just suck air from the room.
- Lower volume of air going through the scrubber means you can have a smaller scrubber or scrubbing is done better.
- Lower air volume through the ducting means less resistance and higher flow / better drag from your hood.

Göran


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## goldenchild (Apr 17, 2014)

From the picture it appears you are trying to use the venturi effect. I have experimented with it before and come to the conclusion that it is somewhat but not sufficiently effective. I think you would need a very large blower if that is what you are going for. A bit confused about where the fumes are going once it has left the hood. Is it going to both the scrubber and sealed buckets at the same time? Attached is my venturi effect experiment. Also a drawing of a different approach. It would involve using some kind of sprayer/pump to keep your media wet by recycling the neutralizer within the buckets. You would of course need to monitor the PH. It would also probably be a good idea to keep this system very modular.






[youtube]http://www.youtube.com/watch?v=-4oQU-SyYZY&feature=share&list=UUulJxV7L-c3hiBhghfk1MYA&index=5[/youtube]


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## mls26cwru (Apr 17, 2014)

just throwing a couple cents in here...

have you considered the volume of the fumes you need to scrub vs. the volume of air you would need to scrub to maintain safe fume hood operation? the latter could be rather large and require a large scrubber with a long residence time forcing the scrubber to be unessecarly large.

also, i have always thought of a fume hood as a "fail-safe" measure that should enclose the work you are doing. If something catastrophic goes wrong you should always be able to isolate your work and vent the air in the hood out of the building. With the scrubber in-line with the fume hood exaust, both systems have to work to maintain safe operation.

If you are doing a smaller volume of work, you could design a scaled down scrubbing system sufficent for your reaction and bring it inside your hood. For a larger indusrtial sized scrubber, you would have to design a separate closed system. Either way, the systems would operating independantly of each other and add an extra layer of saftey.


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## IntelGold (Apr 23, 2014)

Thanks everyone for all your input. I was curious whether a Gas Blower would work? I have included some pics. Any advice would be welcome. Should I pull or push the fumes?




Thanks.


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## goldenchild (Apr 23, 2014)

How would you make it run? Also, being that its all metal construction it would go to hell quickly. That is unless you protect it somehow. The one in my video is in fact all metal but it came painted and I used spray on truck bed liner. I think it lasted 2-3 years with regular use.


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## IntelGold (Apr 23, 2014)

I have re-thought the idea of using this sort of blower. Its hard to find the fittings. I think I will go for this one -
http://www.ebay.co.uk/itm/Inline-Duct-STUBE150-6-100mm-Extractor-Hydroponics-Bathroom-Fan-700m3-h-/390686002408?pt=UK_Baby_Baby_Feeding_Bottle_Warmers_Coolers_LE&var=&hash=item5af6b34ce8
Probably the 6 inch model. Should hold up better if I give it a coat of Epoxy Spray. May need to get it re-balanced though. Any idea's welcome.
Cheers for all your help guys.


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## butcher (Apr 23, 2014)

If your handy maybe you can try a home made fan, find a plastic fan blade about the size needed, take the plastic fan blade out of a the old household fan.

Mount it to a stainless steel shaft, this fan blade will mount in a pipe after the turn of an elbow in the plastic piping (duct work), a hole in the back of the elbow for the fans shaft, external bearings hold the fans shaft in alignment, a motor, coupling (or pulley) to a the motor turns the shaft, only the stainless steel rod and the plastic fan blade exposed to the acidic environment in the duct work, motor and bearings externally mounted on the back of the elbow.

You may just find a plastic squirrel cage fan out of an old fan like a dryer, or one of these http://www.ebay.com/itm/like/120951100484?lpid=82
mount it to a stainless steel shaft and build the box for the fan, keeping the motor and bearings outside of the acid fumes(you may also find the plastic fan shroud out of an old dryer:
https://www.google.com/search?q=dryer+plastic+squirrel+cage+fan&noj=1&tbm=isch&source=lnms&sa=X&ei=US1YU6_6N-jcyQHgiYBA&ved=0CAgQ_AUoAQ&biw=1024&bih=618
http://www.partselect.com/PS418726-Frigidaire-131775600-Blower-Housing-with-Blower-Wheel.htm


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## goldenchild (Apr 23, 2014)

This is the exact blower I use (also in video).

http://greendoorhydro.com/active-air-465-cfm-active-air-blower-system.html

You would need an adapter for your pipe like here.

http://florahydroponics.com/index.p...nfo&cPath=10_13&products_id=1538#.U1hg5GbD8dU

florohydro use to sell on ebay but it looks like they have stopped. I would buy both items from florohydro but it seems they don't have the 465cm blower. I guess you would have to order from each site. Also, you only need to buy 1 adapter as it doesn't take much damage at all. I originally bought 2 but never used the second one. If you could replace the stock squirrel cage with a plastic one you would really be set as that is the part that goes. So for about $120 you are making a very good investment in my opinion. Just don't forget to use the bedliner!


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## IntelGold (Apr 29, 2014)

Thanks for all the input guys. I have been drawing up more rough sketches, hoping one of them will work. I have drawn a system that will draw air from the fume hood and the reaction buckets at the same time. I have placed blastgates at certain points hoping that I can just use blast gate number 1 (the one inline with the main extractor)in a closed position to extract just the fumes from the buckets and not the hood. When the fume hood is not in use the fumes from the buckets still need to be extracted. This means I can use the inline motor to extract and the fumes don't touch the main motor. The fumes would go straight to the exhaust. Maybe the inline motor would not last long but at around £10 they can be easily replaced. Let me know what you think and if you can improve on the idea?


Thanks.


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## butcher (Apr 29, 2014)

Trying to scrub the exhaust from a fume hood you will need a very large scrubber, the fume hood moves large volumes of air through it, the fumes from your reactions mix with this large volume of air flowing through the fume hood, making a larger volume to scrub.

In my opinion it would be better to scrub only the fumes from the reaction vessels (not mixed with all of the air flowing through the fume hood), this way the scrubber needed can be a much smaller unit, and anything that escapes the scrubber system as gases can be vented via the fume hood.


This would make the whole setup more simple, and effective, in my opinion.


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## Smack (Apr 29, 2014)

If you want to use a growers fan then look at this one, it's almost all plastic and they have a 6 and 8 inch in the S-line with good CFM, the 8" is rated at 728 CFM at zero atmosphere.

http://www.ebay.com/itm/New-Vortex-8-S-Line-Inline-Duct-Fan-Blower-Hydroponics-Exhaust-Atmosphere-S-800-/390825935753?pt=LH_DefaultDomain_0&hash=item5aff0a8389

Update: Thought I would include the Manufacturers website. http://www.atmosphere.com/


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## goldenchild (Apr 29, 2014)

It looks like you would need a beast of a blower! Remember for every cubic foot of space, you need 100cfm. This is before we even start to consider all the media the fumes will be pulled through. Also, the "inline motor fans" look like they would be competing with the main fan. One may even cancel out the other. I also don't understand what the buckets are doing. Is the last bucket on the far right somehow connected to the fan? If not the buckets will simply be sitting there as the fumes get pulled through the limestone.

Why not push the fumes through everything instead of pull? If you made a simple inline design where the buckets and limestone are next to each other it would give the fumes enough contact time to be scrubbed.

Edit: I think I see what you are trying to achieve a little better at second glance. With the end cap and drilled holes I think you are trying to retard the amount of fumes that initially go into the limestone to then go into the buckets. The problem with this is that the fumes will not only go down into the buckets but they will also go right back up to the fume hood. It's essentially a bottleneck. The cap and the drilled holes are actually making the system even more ineffective. Until you explain your design this is all speculation and if I am wrong I apologize.


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## IntelGold (Apr 29, 2014)

Hi Butcher, The main motor on the right hand side does all the pulling of air. I do not have any scrubbing system on the fume hood. My aim was to pull the air from both the fume hood and the reaction buckets in one go. Main fan would be on when I was using the hood, Inline fan on the rest of the time. So sometimes the inline fan would be on 24/7. This way scrubbing would be done before both motors. It would not be very powerful using the inline motor but as long as it kept the fumes from escaping into the fume hood and out. I may have over engineered things a bit but want a system like this so its all kept indoors.
Thanks.


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## IntelGold (Apr 29, 2014)

When I use the hood the main fan is on. When im not using the hood I would use the inline motor. Not both at the same time. The blastgates are there to block either pipe depending on which motor you are using. The buckets are sealed with reactions in them. They are joined by a piping system which i have yet to figure out? Because they are sealed I have a blastgate to protect against backdrafts.


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## Anonymous (Apr 29, 2014)

I found this thread by 4metals to be very useful indeed.

http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=40&t=19965&hilit=fume+hood


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## IntelGold (Apr 30, 2014)

If I use a motor like this surely it would work its specs are - 1300m3/hr at max pressure of 800Pa. 
http://www.ebay.co.uk/itm/301118285130?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
I have read the link, thanks. I think I haven't explained very well in my drawing what I am trying to achieve.
I will try and do another drawing which better describes my intentions clearer. I want to scrub the reaction buckets and the hood at the same time.
The fan I have listed above is very powerfull and I believe would work. Only problem is the noise level, 60db permanently I think will drive any neighbours mad?
What does everyone think of the sound level being on all the time?
Thanks.


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## goldenchild (Apr 30, 2014)

IntelGold said:


> If I use a motor like this surely it would work its specs are - 1300m3/hr at max pressure of 800Pa.



What does this equate to in cfm?


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## Smack (Apr 30, 2014)

Should be around 1000 to 1100 CFM.


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## Anonymous (Apr 30, 2014)

I don't make a big song and dance about it but my degree studies were in Aeronautical engineering which involved an awful lot of flow/fluid/gas dynamics.

You're trying to extract air from a complete fume cupboard here with a large volume being processed not only through pipes, but also through a severely denser medium. Whether you use solid state scrubbing or liquid scrubbing the challenge is the same i.e. you have to have (at least) the same volume of air exiting the process as entering it. Otherwise it's pointless.

The pressure differences required to take gases from one transport medium to another of higher density are exponentially increasing the denser the secondary medium is. That's actually not very easy to do cheaply when you're talking about the volumes discussed here.


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## goldenchild (May 1, 2014)

spaceships,

Would you say that it would be equally as challenging pushing the fumes through than pulling them through a system?


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## Anonymous (May 1, 2014)

That's a very good question Golden, and I think it would have to be experimented with because it really does depend upon the media that will be used as filtration/scrubbing.

Taking a logical approach though. If you're trying to push it through and the power isn't there to do so then you will just create a back pressure that will cause big problems in the fume hood. All that will be achieved is blasting the contaminated around the hood and possibly the room.

Pulling it through would at least keep a negative pressure in the fume hood. The question would be how much of a negative pressure, and would this be enough to remove all the required volume ?


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## butcher (May 1, 2014)

It would not be much difference if you tried to push or pull the air, a restriction will slow down progress or CFM through the system.
It does not matter how big the fan is, through a restriction you can only move so much volume of air, unless the fan can overcome the pressure or vacuum of the restriction in the system,(fans and blowers work with very low pressures), with fans (not compressors or vacuum pumps desighned to work with higher pressures, or under vacuum), fans or blowers will not easily work against pressure. or a vacuum, the CFM of the system can be limited by the restriction of the system, adding a larger CFM fan will not overcome this problem.


When moving air through a system the CFM through the system is not only sized by the fan, but also by the duct work taking restrictions (sizes of duct work and restrictions in the system) into consideration.


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## Anonymous (May 1, 2014)

As Butcher said 100%.

My wording was not as good though.


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## g_axelsson (May 2, 2014)

Any system trying to push fumes through the scrubber better be leak free, any leak and fumes are pushed out into the room instead of through the scrubber.
If the system pulls the fumes through the scrubber then a leak is only going to pull some additional clean air through the system.

There is another thing to take into consideration too, if the pressure is positive inside the scrubber it will mean a force pushing outwards on the walls. A drum can easily handle a positive pressure. If the pressure is negative a drum could needs some sort of reinforcement as a drum easily collapses.

Göran


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## IntelGold (May 2, 2014)

A Better question maybe, Could you point me to a scrubber fan system which already works. Thanks for all reply's, I am getting what you have said a little better now.


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## IntelGold (May 2, 2014)

http://www.machinemart.co.uk/images/library/product/large/06/060610035.jpg?2
I have gone ahead and bought this wood dust extractor. Its rated at 765m/3 per hr. It makes one hell of a noise. Its stove enamelled, so my next question - Will it still need bed liner? Thankyou.


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## goldenchild (May 2, 2014)

Wow! Until you posted that link I forgot that I had purchased one of those. I bought it and still haven't gotten around to using though. Mine is actually very quite however. Surprising since its nearly double the cfm of the one currently in use. I would say even quieter. I believe the internals are plastic as well which is a bonus. Whenever the one I'm using craps out I will be replacing it with the one in the link below. I plan on bed lining it also. Since the squirrel cage is the part that goes it should last who knows how long.

http://www.harborfreight.com/1-hp-mini-dust-collector-94029.html


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## Anonymous (May 2, 2014)

If I may be so bold to the OP. I think that to try and scrub both the fumes from your fume hood along with the fumes from your processing in one system is a little ambitious, and unnecessary.

You'd be better served splitting the two.


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## IntelGold (May 6, 2014)

Can someone please tell me if its better to use 2 fans inline of each other or split them into 2 separate pipes? I guess what I am really asking, is it better to have double air flow or double pressure for a fume hood. Thanks.


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## butcher (May 6, 2014)

Two fans inline would not work. 

You can use two fans with two ducts.
Remember duct sizing (CFM) as well as fan sizing (CFM), or any openings or restrictions in the system, determine how much CFM (cubic feet per minute of air flow) through the system, not only the sizing of the duct work, but also restrictions like turns or elbows in the duct can also limit the CFM the system can handle, turns or elbows as well as the duct-works shape (like square duct-work with a sharp "L" turn or bend), can cause restrictions to the flow of air through the system.

You have to have as much air coming in as going out, the building (the fume hood is in) would need a fresh air supply from the outside, a closed room cannot exhaust air if no air is coming into the room, the fume hood opening size large or small (full open or partially closed) will determine how much air can pass through it (size CFM), the fan needs sized for the fume hood hood opening (full open door), the duct-work also needs sized large enough for all of the air to flow through it taking restrictions of the duct into consideration (size of duct, turns elbows...)

Try sucking air out of a coke bottle, no air coming in, you cannot suck air out.
Try blowing air into the coke bottle, no air leaving the bottle, you cannot blow air in.

Air, water, or other medium, trying to be forced through a small orifice builds a back pressure on the hose or duct system, as you can only push so much through that small hole. the same with pulling the medium, an orifice, or restriction would crate a vacuum as you can still only get so much through that hole over a given time {CFM or some other measurement of volume and time like GPM (gallons per minute)}, the larger the orifice the easier it is for the medium to flow through it.

An over sized duct or orifice will not cause a restriction. 

An over sized fan could only push or pull as much air as the duct, openings or restrictions allow, which could set the fan motor up for problems like overheating of the motors windings...

(kind of of hard for me to explain).


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## IntelGold (May 6, 2014)

Thanks Butcher, Very nicely explained. "Try sucking air out of a coke bottle, no air coming in, you cannot suck air out.
Try blowing air into the coke bottle, no air leaving the bottle, you cannot blow air in." Really like this Example.  
I have drawn up so many pics now its unreal. I have posted a pic below of the rough idea. If you ask why have I gone for 2 fans, its because they are both sucking the same amount of air x 2 because they can be adjusted so they are at exactly the same speed. The speed controller can control both at the same time. The fans also have twin speeds. If 1 fails I have the other to back it up, maybe not 100% but anything would do in a emergency. The red lines I have drawn are the shed walls. Its only a small hood, measures 40" x 24". All piping is 6" (150mm). I was going to have 5 foot of pipe with packing material in it. I now realize that instead I should use a large container which has been strengthened. The pipe would go into the water and bubble up which slightly scrubs the gases. With packing I am hoping to scrub most of the fumes before they hit the fans. I have also drawn a green square round the 2 pipes nearest the floor, it has red stripes going through it. This would be a large bucket/container filled 3/4 of the way up. The 2 pipes would then be inserted into the scrubbing media.
I really think I should do another drawing as i maybe confusing people. Sorry. 
A water pump and Spray Bar would help also. Please comment. Any comments a good comment.
Thanks.


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## IntelGold (May 6, 2014)

Forgot to say they have Thermally protected motors so over heating should not be an issue. Each fan would produce 530 m3/hr. I am not sure whether this would equate to 1060 m3/hr. I'm sure someone on this site will know. I like the fact that the fans can be turned up or down dependent on the Scenario. They might pull the fumes through nicely on 3/4 speed controller setting.
I also think that the first fan which is pushing air is not needed and will just cause complications in the flow of air.
Lots of thoughts going through my head at the moment. Sorry if I'm babbling.


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## IntelGold (May 6, 2014)

I would also like to add that my shed is very well ventilated. So outside air being drawn into the shed is not a problem. Imagine that i am almost working outside.... :idea:


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## butcher (May 6, 2014)

I may not understand the scrubber you are talking about, but getting that volume of air through a bucket of water would put a kink in the system.

The air should flow fairly free through the scrubber.

Again you can use a simpler small scrubber that just scrubs fumes from the reaction vessels, without scrubbing all of the fume hoods air. 

If you feel you must scrub all of the air from the fume hood, the scrubber will have to be extremely large the air would not bubble through water, but flow through the scrubber easily (it may need baffles or a medium to slow it down some having to make twists and turns like flowing around some type of medium, but basically not restricted in flow, a scrubbing solution can be misted into the scrubber where the gases pick up moisture and the gases can convert to acids or are neutralized, think really tall and large scrubbers something all of your neighbors will see towering over your roof top.

Spend some more time studying scrubbers and fume hoods, it looks to me like you are working from the wrong end of the hammer, you are making all of the plans of how you will build the house, but have not yet understood how the house needs to be built.


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## 4metals (May 6, 2014)

This spreadsheet may help you understand just how big fume scrubbers have to be to handle all of the fume coming out of a hood. 

The box on the left allows you to put in the diameter of the scrubber and the depth of the packing. Then it tells you how many Cubic feet per minute of air it can effectively scrub with an 8 second retention time. 

On the right are opening sizes for 3 hoods. Put in the length and height of your hood opening and it will tell you the total CFM required to maintain 100 CFM face velocity. This is considered a fugitive emission. 

The ideal setup is to provide an exhaust as listed to maintain the 100 CFM face velocity and this is non scrubbed air, it just makes the work environment pleasant for the refiner working in front of the hood. 

The size of the scrubber determines the CFM it can handle, that size scrubber receives the fume from enclosed reactions in the hood. This is the scrubbed emission.

View attachment scrubber sizing and blower sizing.xlsx


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## Anonymous (May 7, 2014)

butcher said:


> I may not understand the scrubber you are talking about, but getting that volume of air through a bucket of water would put a kink in the system.
> 
> The air should flow fairly free through the scrubber.
> 
> ...



This is what I too have politely been trying to say Butcher but it doesn't appear to be registering with the OP. He appears hell bent on doing what he set out to do regardless. Best of luck I guess.


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## rickbb (May 8, 2014)

spaceships said:


> If I may be so bold to the OP. I think that to try and scrub both the fumes from your fume hood along with the fumes from your processing in one system is a little ambitious, and unnecessary.
> 
> You'd be better served splitting the two.



This is my thinking. Get the right tool for the job at hand. 

I don't see a need to scrub every cubic inch of air in the fume hood 100% of the time. (Unless you are setting up a large scale commercial operation of course.) 

You only need to scrub what is coming off any digestion/reaction vessel while it's in operation, then feed the scrubbed outflow from the scrubber into the general hood exhaust.


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## Anonymous (May 8, 2014)

Rick I tell you what annoys me.

People come and ask for advice and in many cases when they are told something that they don't want to hear- they just disappear (probably ignoring the advice completely to boot.) Even worse they ignore the posts they don't want to hear and only acknowledge those that might fit into their view of things.

In this particular case professional refiners (I don't include myself in this) have stated that for a home user this plan is impractical and too expensive, and maybe a different approach is required. However every post where this is stated is completely ignored. Do people really think that the "pros" are stupid and that they know better?

From a personal perspective and after having spent my time trying to help, I find this (respectfully) to be completely ignorant.


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## butcher (May 8, 2014)

spaceships,
I agree sometimes that is the case, sometimes too often, and it can be frustrating for those trying to help, and dangerous or unprofitable for the offenders.

We can also give the benefit of doubt.

In this case it can be more of not understanding, or needing someone to say things differently before it clicks, or that light bulb comes on, I think in this case studying would help to answer most of the questions, give a better understanding of what is needed, then questions would also be more in line, and the answers would also make more sense, having at least a basic understanding of what is needed to build the system, and a better understanding of questions and answers needed along the way.

There seems to be a lot of work and planning going into this system,which is good, but I also think he just needs to learn to hitch his horse in front of the cart, before going to town on it.
Study and then make the plans.


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## necromancer (May 9, 2014)

yes Butcher, i agree.

what the OP needs to do is not over think things, its great that they want to scrub everything but its not needed

its like looking for your glasses for an hour then remembering that there on your head  

take 2 steps back, make a sandwich do something different & the thoughts will come on there own. forcing a thought sometimes makes it harder to think

climb outside the box, take a deep breath & next thing you know you will be building your hood.


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## 4metals (May 9, 2014)

Part of what makes this forum so good is that there is such a wide range of experience all looking at the topic, any topic, from a different perspective. From that come some very good and fresh ideas. 

As far as the chemistry of refining goes, the new "discoveries" come to the group because of the same diversity or from the lack of ability to acquire the required chemicals. This is all good and it helps all who read and follow these threads to be more diverse. 

But for something like a hood and scrubber, there are alternatives, all of which have been tried and proven or disproven. At this point its like re-inventing the wheel. It can't get any more efficient than round!


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## IntelGold (May 11, 2014)

spaceships said:


> Rick I tell you what annoys me.
> 
> People come and ask for advice and in many cases when they are told something that they don't want to hear- they just disappear (probably ignoring the advice completely to boot.) Even worse they ignore the posts they don't want to hear and only acknowledge those that might fit into their view of things.
> 
> ...



I am currently rethinking my design hence why I have not replied yet. I have taken everything on board. I am not ignorant. Allegedly I think pro's are stupid which is definitely not the case. No disrespect on my part.


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## Anonymous (May 11, 2014)

Thanks for the reply Intel, look forwards to seeing your re thought out design.

Jon


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## Smack (May 17, 2014)

IntelGold, have you looked at the Fume Hood Guide?
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=54&t=12641&p=125972&hilit=fume+hood+guide#p125972


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## Anonymous (May 22, 2014)

Did the OP get a chance to come back with the new design?


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