Thread: Alternative Dust Extraction Solution

soundman,

thanks once again. I am very slowly getting there

cheers

Mick

The difference between my DB levels and John's will always remain a mystery. I had to do considerably more than John as far as silencing goes and I still didn't get down to John's levels. Whether it was the fact that I have a plywood panelled steel garage and John has(I think) a brick building or whether it is something else entirely I have no idea.

When it comes to noise, and especially mounting equipment, the construction of the building and how you mount stuff has a great deal of influence.

As you may have gathered I am Soundman...I can take the same speaker with the same programe and the same power applied and it will behave a great deal differently in different envoronments......you can take a rig into a favorable environment and it will rip peoples heads off, take it to somewhere less...advantageous and you will feel like you have taken a knife to a gunfight.

When it comes to machinery, what you mount to and how you mount it can make dramatic differences.

My workshop compressor used to sit directly on the concrete slab of my workshop, on its rubber wheels and 1 rubber stopper.
It was not until I built a decoupling base for it I realised how much the concrete slab was coupling with the compressor.....yess the 6 inch concrete slab.

I simple reinforced 18mm plywood board with some EVA foam strips on the bottom and the low frequency noise in my shed has dropped dramatically.....in the past I could clearly hear the drumming of the compressor in the house.....the house is on a seperate slab.
Now I can still hear the compressor when things are quiet, but not the drumming.

In industry and in particular in the refrigeration & air conditioning business, isolating machines from the building structure and isolating ducts, hoses pipes and cables from the machine and the structure are very important issues.

In one of the venues I currently work at they have converted what was previoulsy a large utility space to a function room.
Great we all thaught, till they fired up the late 60's early 70's big ass Carrier air conditioning plant on the slab above......now this is a big V4 thumper driven by a motor about 3 feet in diameter....and the whele thing sits direcly on the slab.....I thaught they would never shut this thing up....not even close....there was no way they where going to lift this monster onto isolating blocks.

But they got the airconditioning boys in, I don't know what they did, but this plant still sits directly on the slab.
They must have isolated the refrigerant pipes where they exit the building to go to the cooling tower or something.

Its not whisper quite by a long shot, but its a hell of a lot quieter than it was.

what you have mounted you blower to and how you have isolated it could make a huge difference.

cheers

Thanks for the insight Soundman.

My CV is mounted on a pine 2x4 tower that sits on the concrete floor and is not attached to the wall. Perhaps I could try your solution and pack between the frame and the floor. Can you please tell me what EVA is and where I could buy it or maybe you could suggest another product. I have gone about as far as I can with sound deadening and silencing.

thanks

EVA is a reasonably hard foam, like an expensive relative to that thongs are made of.

The first thing I'd be doing is making sure the frame is as rigid and as non resonant as possible.

Adding traingular plywood or masonate braces glued and screwed to all joints will be a start.

putting a bucket or box in the bottom filled with sand or heavy gravel is another step.

depending on how stable the tower is..may be some rubber or heavy foam under the base.

realy the first thing is to establish where the noise is comming from...often that can be decieving.

some automotive body deadning mat.....often self adhesive on the blower body may help.

I have acoustic panels, in several places in my shop that knock out sound pretty damn well.

Behind my drop saw, I have MDF boards with a layer of 10mm cotton waste wadding covererd in front runner.....my mate an acoustic engineer was scheptical as to the effectiveness, bet let me tell you it knocked out the high frequency noise of cutting aluminium pretty well.

A realy effective noise absorber can be made out of 90mm pine studs, backed with whatever board you have on one side and filled with R2.5 bats and then some sort of fabric...if using fibreglass, put some plastic sheet over the front before your fabric.....best t glue the bats into the back of the frame with spray glue.

If you are trying to knock out low frequencies you need at least a 100mm cavity to be effective so we then get into making boxes with plywood sides to get the depth.

I also have various foam acoustic tiles in places that where surplus from treatment contracts.

If you want to reduce noise in your workshop, well placed acoustic absorbers can be very effective.

cheers

Soundman how would acoustic tiles used in drop ceilings do as a layer inside a dusty cabinet, on the outside, or both sides?

Pete

Those paper composite acoustic tiles are not great acoustic absorbers......in a ceiling that make a pretty decent difference compared with hard surface tiles because of the large amount of surface involved.
most of that difference however is in the mids and tops.

For low frequecy absorbtion you need thickness, and for effective absorbtion you need soft material.

Now remember there are two issues involved in acoustic treatment.

Absorbtion and transmission.

Absorbtion functions on surfaces, so that the noise hits the surface and is not reflected to continue in the room or container.
get an absorber good and close to a noise source and you can remove nearly half the sound energy from the room due to that item

Transmission, we try to reduce to keep noise in or out.....we are generally looking for dead, heavy materials.....18+mm MDF is pretty damn good

In an interiour space we can treat transmission as much as we like, but with out absorbtion the noise will just bounce arround till it finds a way out.

sometimes materials function as absorbers and to reduce transmission.

The simplest test is the shout test.

to test for absorbtion......stick ya face about a foot away from the surface and shout at it......compare that to shouting into open air and into a hrad bright surface and the difference will be obvious.

the test for transmission is similar...but often not as effective.

I had a lady wanted to mount a heavy vinyl poster in front of one of my speakers the other day....she asked how much difference it would make.......I stood up and spoke straight at her...then put the poster in front of my face.
the difference was obvious.

The above wont give figures, but for a workin' man it may be all you need.

cheers

Originally Posted by ronboult

Hi Mick
Are you aware that with any Cyclone the Cone and the Fan DO NOT have to be close coupled.

With the CV the motor housing is designed to be screwed directly to the top of the Cone.
However the two can be separated and connected with suitable sized ducting.

I have read somewhere on the web of someone having similar height restriction to you and he used a 90 degree bend and pipe between the cone & blower to lower the total height. You could even put the cone in the workshop and have the blower outside.
This may be a better solution than tilting the cyclone on a 45 deg angle
Ron

Ron,
I could not find this anywhere. I also joined the CV forum and asked the same question on the weekend but have not had any reply. I cannot say I'd like to be the first to try this!

At the moment I am leaning towards the 3hp Felder AF22 D-160. BobL previously posted below about this machine based on stats from gunnaduit. Unfortunately it will mean going without a cyclone to get the magic numbers. I have used BP's staticcalc as well for what I am expecting to do

Originally Posted by BobL

These curves are measured by simply restricting the inlet and then a manometer is placed between the inlet and atmosphere and measuring press as a function of flow. Forget the 20 m/s, it's better to use these curves the other way and ask what pressure is generated at 1000 cfm. In the case of the 160 mm OD that pressure is 9". This is quite good and means you have 9" of pressure to play with and can add ducting, connectors and machinery that will "use up" this 9" of pressure and still retain the 1000 cfm.

On Bill Pentz staticcalc spread sheet 9" of pressure using 6" ducting equates to about.
one hood (0.45")
2 large radius 90º bends (1")
1 Wye (0.52"")
30 ft of straight ducting (2.04")
1 90º flex hose 3 ft long (1.88")
1 standard < 5 micron bag (1")
+ 2" for "other stuff" such as the machine being vented.

Ideally you shouldn't let the pressure drop go down to zero but you should keep a couple of inches of press in reserve in case of light blockages so that the system can overcome these and get back to normal.
The staticcalc spread sheet is really the simplest way of doing the sums that you need to sort out your system.

this certainly seems to be full of compromises. I think of this as trading off noise (and getting up and running time) for having to keep filters clean. Either way I will have to empty the chips / dust.

cheers

Mick

Mick
have a look at this link.

Building a Bill Pentz's Designed Cyclone

the cyclone is not a clearview but is built to bill pentz design

also I am sure I have seen another example of decoupled fan &cone on the web.

do a search on google
cheers
Ron

Ron,

a great link. I had seen other tailor made ones with the blower and motor separate (in fact you can attach a normal DC to the cyclone) but I don't know how easy this would be for a CV, especially as it does not appear it has been done. I will do some further research.

thanks

Mick

Mick
Attaching ducting to the top of a CV Cone would be very easy. The cone and blower have two mdf disks, one in the top of the cone and the bottom of the blower. Normally you just line up the central holes in both and screw them together with particle board screws. The screws go through the bottom of the Blower housing ( there are predrilled starter holes in the blower bottom plate) and into the mdf disk in the top of the Cone.

If you were to cut a MDF disk the same OD as the cone and cut a central hole same size as the cental duct you could use this to attach ducting which would be completely removable. This would not damage the CV and it could be returned to the normal state if required.

In fact if my system proves to be too noisy and I cant quieten the sound I will end up doing this to mine and shift the Blower & exhaust out of the workshop

Ron

I can asure you will not be the first to mount a fan seperate from the cyclone.....as I have said before, it is and has been very common... in the past actually more the case than the exception........in fact some would consider mounting the fan direct on the top of the cyclone a compromise.....it will reduce the performance not a scrap if done properly.....in fact seperating the fan from the cyclone may reduce turbulance and marginally increase its dust seperation performance.

In fact..sucked or blown..a given properly desigend cyclone will not care a scrap as long as the airflow is sufficient.

Cyclones are far less fussy than some people will lead you to believe....as long as the air flow is sufficient and the flow is smooth comming in and out they can not but work well.

NOW
Consider this.....If I was to build a new cyclone....I would probably start with a standard dust extractor.....the hardest part of the work is already done....building the transition from the incomming duct to the hoop.

I'd cut and shut a 44 gal drum for the cylindrical outer body, a 20 litre drum for the riser cylinder and hand roll the cone.....I recon knowing what I now know....It would cost maybe $100 in materials and a weekend would kill it.

I would not bother with an air ramp......they only improve the top end of the efficiency a couple of decimal points of a persentage.

Id run it as a blown cyclone using the blower provided with the dust extractor. and with a little inventivness....a second cone could be fitted above the cyclone and a standard bag or pleated cartrige filter stood on top of the unit....dust beaten out of the bag or pleated cartrige ..when the machine is off..would fall down the second cone and down the riser tube into the cyclone and into the dust container.

But with a decent sized dust drum.....like a whole 44...its going to be 4 meters tall.....BUT ...its going to be a full sized 24 inch cyclone with the correct ratio between the 6 inch inlet pipe and the 12 inch riser tube .......AND....its gona work and pretty damn well.

Blowing into the cyclone causes less static pressure loss, so a smaller motor/ blower would be tolerable.

As I say in the first flush of cyclones 10 years ago......ALL of the commercially available cyclones where rediculously expensive or poor performers......dozens of us on this forum and elsewhere built our own from scratch.....there where many variations and most worked very very well.

I can remember at the time a couple of people built bassed on an off the shelf 2Hp dust extractor more or less as detailed above.
Yes the 2 hp blower was a little marginal but with short ducts, some efficiency mods AND the fact that it is a full sized 24 inch cyclone.....they worked well.

cheers

Originally Posted by ronboult

Mick
Attaching ducting to the top of a CV Cone would be very easy. The cone and blower have two mdf disks, one in the top of the cone and the bottom of the blower. Normally you just line up the central holes in both and screw them together with particle board screws. The screws go through the bottom of the Blower housing ( there are predrilled starter holes in the blower bottom plate) and into the mdf disk in the top of the Cone.

If you were to cut a MDF disk the same OD as the cone and cut a central hole same size as the cental duct you could use this to attach ducting which would be completely removable. This would not damage the CV and it could be returned to the normal state if required.

In fact if my system proves to be too noisy and I cant quieten the sound I will end up doing this to mine and shift the Blower & exhaust out of the workshop

Ron

Ron,
this sounds like a very possible answer for me (and I nearly even understood what you wrote )and even with my limited handyman skills it does seem doable. I don't know why someone on the CV site did not think of this......I'll also have a chat to Stephen to make sure he does not see an issue.

soundman - I at least partially understood what you said but I am not sure I am capable of that much of a build. The less I have to build the system the better. For me, paying the $ to get components that I know will work is a much better idea, even at the expense of how good (or how much) red wine I will be able to afford . I can see this being hard enough in any case but think it will be worth it in the long term.

Not that I am at all doubting Ron but before I consider going bleeding edge do other CV users think it would be this easy to separate the cyclone from the impeller and motor?

As always, very very much appreciated

Mick

Originally Posted by ronboult

Mick
Attaching ducting to the top of a CV Cone would be very easy. The cone and blower have two mdf disks, one in the top of the cone and the bottom of the blower. Normally you just line up the central holes in both and screw them together with particle board screws. The screws go through the bottom of the Blower housing ( there are predrilled starter holes in the blower bottom plate) and into the mdf disk in the top of the Cone.

If you were to cut a MDF disk the same OD as the cone and cut a central hole same size as the cental duct you could use this to attach ducting which would be completely removable. This would not damage the CV and it could be returned to the normal state if required.

In fact if my system proves to be too noisy and I cant quieten the sound I will end up doing this to mine and shift the Blower & exhaust out of the workshop

Ron

I am dearly hoping that some others who have installed CVs (eg: John rusel, safari,.....) give an opinion on what Ron has written, even if it is 'not really sure about that' but hopefully it is 'yep - sounds like a goer'. I have been stalking and know that some of you have been on-line . I would also be interested in others with far more expertise than me (BobL for one) also commented. From my interpretation I believe that soundman thinks it is a goer.

I feel a bit like I am spamming but also I am getting very close so I can't stop now

cheers

Mick