Thread: Wall Mounted Dust Extraction Fan

I'll be interested on seeing what you end up with, i've been looking at my options over the last few weeks, and i have 3 options.

Utilise my Felder AF16 with the 1 micron filter and build a suction wall box with AC hinged ducted grille screens, but the Dusty plus out close to 98 db.

Buy a dust extraction filter from Hare and Forbes (has Centrifugal Fan, with two filters)

Build a dust extraction filter with the Centrifugal blower fan or VEVOR Ventilation Extractor Exhaust Fan Blower 12''/300mm 150W Air Blower Silent | VEVOR AU, along with hinged AC ducted grille with various filter grades

The issue i have is that i have is i can't duct it out of my industrial workshop, so i have to make sure the filters are getting down to 1 micron.

I use my dusty and also my festool vac while using tools and machinery, but that fine dust has been etching itself into the paint on my camper that i store in there.

the easiest option i think for me is to just pick up a hare and forbes unit, as the filters are reasonably priced, already has a timer and remote and is a lot less noise than using the dusty as a air filtration unit

Originally Posted by Compass

I'm tossing up between these 2,

12 INCH DUCT FAN Inline Centrifugal Exhaust Ventilation Heavy Duty Fan Blower | eBay

x2(Two) 146mm 220V Double Inlet Centrifugal Blower Fan DYF 4E-146-QS2a, NEW | eBay

Either fan will do the job but you might want to consider the following.

The first one (Centrifugal fan) is cheaper to buy but uses 246W compared to the Squirrel cage fan (85W) so the latter will be cheaper to run.

The Centrifugal one claims 1100 m^3/Hr.
At 65 cubic m that works out to 17 room air changes per hour
The squirrel cage is 830 m^3/hr, or ~13 room air changes per hour

Neither figures are probably absolutely accurate but the Centrifugal one should still move more air.

Noise wise they are about the same( 54 v 55 db) but squirrel cage fans are usually quieter.

Originally Posted by BobL

Either fan will do the job but you might want to consider the following.

The first one (Centrifugal fan) is cheaper to buy but uses 246W compared to the Squirrel cage fan (85W) so the latter will be cheaper to run.

The Centrifugal one claims 1100 m^3/Hr.
At 65 cubic m that works out to 17 room air changes per hour


The squirrel cage is 830 m^3/hr, or ~13 room air changes per hour

Neither figures are probably absolutely accurate but the Centrifugal one should still move more air.

Noise wise they are about the same( 54 v 55 db) but squirrel cage fans are usually quieter.

Think I'll go with the Squirrel, I didnt see the power rating of the Centrifugal when I first looked, Think the Squirrel will be easier to mount too, seeing as it has a flange.

Originally Posted by bryn23

I'll be interested on seeing what you end up with, i've been looking at my options over the last few weeks, and i have 3 options.

Utilise my Felder AF16 with the 1 micron filter and build a suction wall box with AC hinged ducted grille screens, but the Dusty plus out close to 98 db.

Buy a dust extraction filter from Hare and Forbes (has Centrifugal Fan, with two filters)

Build a dust extraction filter with the Centrifugal blower fan or VEVOR Ventilation Extractor Exhaust Fan Blower 12''/300mm 150W Air Blower Silent | VEVOR AU, along with hinged AC ducted grille with various filter grades

The issue i have is that i have is i can't duct it out of my industrial workshop, so i have to make sure the filters are getting down to 1 micron.

I use my dusty and also my festool vac while using tools and machinery, but that fine dust has been etching itself into the paint on my camper that i store in there.

the easiest option i think for me is to just pick up a hare and forbes unit, as the filters are reasonably priced, already has a timer and remote and is a lot less noise than using the dusty as a air filtration unit

The Vevor looks very loud!.....is this what your talking about from H&F....W325 - AF-400 Two Stage Air Filtration Unit | Hare & Forbes Machineryhouse

I'll be using this to cool my shed too, as when the vacuum, cnc and compressor are going it's like an oven

The Vevor fan Ad is contradictory. In one part it says ultra-quiet 50dB operation, while another says 68-72 dB.
As it's an axial fan these always make a lot of noise when they move air so it's probably going to be even louder than the second figure.

I seriously doubt it will move the claimed 2850 m^3/hr.
These measurement are usually made by measuring the air speed meter in front of the fan and multiplying it by the fan area.
BUT
The flow through the fan is seriously constricted by the grille, and the fan blades themselves so they end up using an area value that is much larger than it is in practice to mathematically generate a false air flow rate.
This is pretty common and over estimates of a factor if 2X or more are not uncommon.

To perform the flow test accurately one needs a long test pipe in front of the fan and the air speed across the radius of the pipe needs to measure in multiple places. This takes a lot of time and is why most commercial flow rates are just wrong.
Testduct.jpg

Originally Posted by Compass

The Vevor looks very loud!.....is this what your talking about from H&F....W325 - AF-400 Two Stage Air Filtration Unit | Hare & Forbes Machineryhouse

I'll be using this to cool my shed too, as when the vacuum, cnc and compressor are going it's like an oven

Yeah after looking more into it, BobL is right about the higher noise levels with the Vevor fan. no one wants to put up with that noise level.

The model i was looking at is the W326 - AP-12 Two Stage Air Filtration Unit | Hare & Forbes Machineryhouse as i have a bigger area, But only because i can't vent directly outside.

If you can, pumping that fine dust straight outside is better and you don't require filters. don't forget to check out Gumtree for single phase blowers, you might be able to pick up a larger single phase unit.

Originally Posted by BobL

The Vevor fan Ad is contradictory. In one part it says ultra-quiet 50dB operation, while another says 68-72 dB.
As it's an axial fan these always make a lot of noise when they move air so it's probably going to be even louder than the second figure.

I seriously doubt it will move the claimed 2850 m^3/hr.
These measurement are usually made by measuring the air speed meter in front of the fan and multiplying it by the fan area.
BUT
The flow through the fan is seriously constricted by the grille, and the fan blades themselves so they end up using an area value that is much larger than it is in practice to mathematically generate a false air flow rate.
This is pretty common and over estimates of a factor if 2X or more are not uncommon.

To perform the flow test accurately one needs a long test pipe in front of the fan and the air speed across the radius of the pipe needs to measure in multiple places. This takes a lot of time and is why most commercial flow rates are just wrong.
Testduct.jpg

Thanks for the info Bob, its easy to miss the finer details

Quote; 'Noise wise they are about the same( 54 v 55 db) but squirrel cage fans are usually quieter.'
Are those actual or claimed figures? I have one of the centrifigal fans and it sounds like a jet engine. Measures 60db on my phone app. at 2m.
I have another radial kitchen type fan that measures 56db at 2m. surprisingly both together only measure 62db.
The DE with one outlet open is 63db and with the 2 fans is only 64db

Originally Posted by Flintlock

Quote; 'Noise wise they are about the same( 54 v 55 db) but squirrel cage fans are usually quieter.'
Are those actual or claimed figures?

Claimed.

I have one of the centrifigal fans and it sounds like a jet engine. Measures 60db on my phone app. at 2m.

60 dB is hardly jet engine noise, try 120 dB

I have another radial kitchen type fan that measures 56db at 2m. surprisingly both together only measure 62db.

The DE with one outlet open is 63db and with the 2 fans is only 64db

Radial kitchen type fans don't move much air - fan blade speed, fan blade and impeller shape, and restrictions will play a major role in the noise generated.

Sound pressure levels don't combined by simple addition,
If you have two sources of equal sound intensity close together, both together will only produce about 3dB more that either one.
The formula for addition of two SPLs is

SPL_Total = 10·LOG₁₀[10^SPL1/10 + 10^SPL2/10 + 10^SPL3/10 ... + 10^SPLN/10] (dB)

There are a couple of web based calculators that will do the maths for you
eg Logarithmic Addition of Sound Pressure Levels | WKC Group

The kitchen fan (56 dB) Plus teh centrifugal fan ( 60 dB) should produce 61.5 dB at 2m, your measured 62 dB is pretty close

63 plus 62 should produce 65.5 dB . Discrepancies could be due to differences in distances between sound sources

Squirrel fan ordered....should get next week.....will update this post at that time.....thanks everyone for the input

Originally Posted by BobL

Sound pressure levels don't combined by simple addition,
If you have two sources of equal sound intensity close together, both together will only produce about 3dB more that either one.

But 3dB more is double the sound.

Originally Posted by Colin62

But 3dB more is double the sound.

Sure - isn't that what I said? or meant to say

Originally Posted by BobL

Sure - isn't that what I said? or meant to say

Perhaps.

I read what you said as “two sounds of the same level together aren’t double sound, but are only 3dB more”, but I can see that you were actually saying that you don’t add the two dB values together to get the total dB.

Originally Posted by Colin62

Perhaps.

I read what you said as “two sounds of the same level together aren’t double sound, but are only 3dB more”, but I can see that you were actually saying that you don’t add the two dB values together to get the total dB.

Yep that's correct. If you have two equal noisy machines and let's say both produce SPLs of 60 dB @ 2m when either one alone is turned on . Then if both machines are more or less side by side and turned on the total SPL 2m away will be 63 dB.

Same applies if they are both 100 dB or 50 dB.