Thread: a new take on dust extraction

Listed in Australia, no price yet: Harvey G700 Dust Unit - Major Woodworking Equipment

I would be interested to see some independent test results on this. I just bought a Clearvue cyclone, but this thing looks a lot better on paper wit regards to noise (68dba at 3m). Notice however it only has 4" inlets.

Ha been discussed before - it reminds me of Dyson vacuum cleaners - bling on a stick and some fancy marketing.

Reminds me of when cyclones were first introduced in Oz, Bob wasn't so keen on that idea either.

Ha, now I see why there was no interest when I re-posted this.
It actually has a 6" inlet and in the absence of any independent testing or even having seen one operating I think 'bling on a stick' is a bit premature. Fully agree about Dyson products though, you can fool some of the people most of the time!

At that price it's bling on a stick. A Clearvue Max is cheaper and there's a whole lot more of it.

Elan, you come from an industrial situation, not a home workshop. Yeah a Clearvue is great if you've got the head height available to install it! What about the noise factor? Horses for courses. Don't dismiss it out of hand. If you had to work from home, either as a business or a serious hobbyist how would you personally be traveling with a Clearvue?

Originally Posted by aldav

Elan, you come from an industrial situation, not a home workshop. Yeah a Clearvue is great if you've got the head height available to install it! What about the noise factor? Horses for courses. Don't dismiss it out of hand. If you had to work from home, either as a business or a serious hobbyist how would you personally be traveling with a Clearvue?

The Gyro air specs are quite interesting - assuming they have done their flow measurements correctly, which few DC manufacturers do.

The 12" impeller is driven by a 1.5kW motor and can generate a very high static pressure (18.5" of WC) - this is much higher than what a ClearVue can achieve.
It does this by spinning the impeller to 4275 RPM using an inverter running at ~70Hz - if a Clearvue did the same it would come close to doing this.
The dust separation efficiency for the Gyro is very high , 99.7% at 5 microns, versus 99% for the Clearvue.
Bear in mind the Gyro has 2 cyclones which is a easy way to generate high efficiency separation even using inefficient cyclones
eg two 95% efficient cyclones in series will have a Total separation efficiency of 99.75%

However it can only pull a very ordinary 765 CFM though a 6" duct which is MUCH less than a Clearvue (1400-1800 CFM) and less than what is needed for bigger WW machines and especially so if more than one machine is being used on the DC system at the same time.

To move 765 CFM through a 6" duct only requires about 4" of WC, so where are the other 14" of WC going?
My guess is the twin, small cyclone arrangement generates a high back pressure which uses up most of that impressive static pressure to function.
To constrain the overall size it appears they have had to make the cyclones small which would make each one inefficient and this is why they had to use 2 of them.
This combination is probably what generates the high back pressure and stymies the flow rate
This then leads me to wonder about the value they claim for their 4" ducting flows.

The Gyro will certainly have a useful niche operation market like small CNC operations in cold climates, but won't be anywhere near as effective as a ClearVue on larger machinery or where more than one machine needs to operate.

If you cannot fit a ClearVue in your workshop there are plenty of lower height DCs available for much less than half the $$, that can achieve significant better flows than the Gyro.

As far as noise goes, if the DC is located outside or enclosed inside a shed, the noise factor becomes one of how prepared the DIYer is to set up a noise reduction enclosure. Its not rocket science as plenty of folks on this forum have done this. A good sound enclosure can achieve the 61dBA at 3m claimed by the Gyro. Mine is 62dBA at about 1.5m

My CV 1800 runs at 65hz all day and I will run it at 70hz if I need to. It doesn't blow up at that but I haven't the equipment to measure the static pressure though I know it is only a water manometer which is not rocket science to put together. I have always wondered where the peak flow happens and the fan curve falls over.

Originally Posted by Chris Parks

I have always wondered where the peak flow happens and the fan curve falls over.

There will be diminishing returns going to higher and high speeds - another thing to add to the testing list.

Originally Posted by BobL

There will be diminishing returns going to higher and high speeds - another thing to add to the testing list.

I think I said that in not quite those words.

Thanks for that Bob. Where does the 765cfm come from, is it from published test data on this machine?

Originally Posted by BobL

The Gyro air specs are quite interesting - assuming they have done their flow measurements correctly, which few DC manufacturers do.

To move 765 CFM through a 6" duct only requires about 4" of WC, so where are the other 14" of WC going?
My guess is the twin, small cyclone arrangement generates a high back pressure which uses up most of that impressive static pressure to function.

Hi Bob,

Moving 765 CFM through a certain length of 6" duct may produce 4" of system resistance, but a dust collector with a 4" max static pressure could never pull 765CFM through that duct. I think that maybe you are confusing the interaction of the fan and system curves. The Gyro can generate a maximum static pressure of 18.5", but that is of course at zero airflow. Then, the amount of air the system can flow at a particular system resistance (measured in W.C.) depends on the fan curve. So the Gyro's curve may be relatively flat and then steep; perhaps not dropping much ariflow until the higher static-pressure range and then dropping off aggressively.

Cheers,

Dom

Originally Posted by DomAU

So the Gyro's curve may be relatively flat and then steep; perhaps not dropping much ariflow until the higher static-pressure range and then dropping off aggressively.

Which ever way you look at it, 765 CFM through a 6" pipe is not much to crow about. It's less than what a modified 2HP DC can produce, (albeit with improved filtration efficiency) which doesn't matter if the DC is located outside.