Thread: Mens Shed Dust Collection

I don't have the Max version but my exhaust exits the shed via a 9" pipe and then under an adjacent bungalow. I have not seen any dust deposited at the end of the pipe.

Originally Posted by safari

I don't have the Max version but my exhaust exits the shed via a 9" pipe and then under an adjacent bungalow. I have not seen any dust deposited at the end of the pipe.

Thanks Safari, have you got any pics of your ducting etc

Hi BobL, I have taken couple of pics for you. From the Clearview outlet I have run a 9" pipe to the top of the muffler then 9" from the bottom of the muffler to the underneath of the bungalow. The box on the left of the Clearview is my attempt at a muffler. I am hoping you are going to describe how you made your muffler because I am sure it would be much better than mine. We are shifting houses in a few months so I will be starting over so the opportunity will be there to improve things.

Clearview interior.jpgClearview exterior ducting.jpg

Originally Posted by safari

Hi BobL, I have taken couple of pics for you. From the Clearview outlet I have run a 9" pipe to the top of the muffler then 9" from the bottom of the muffler to the underneath of the bungalow. The box on the left of the Clearview is my attempt at a muffler. I am hoping you are going to describe how you made your muffler because I am sure it would be much better than mine. We are shifting houses in a few months so I will be starting over so the opportunity will be there to improve things.

There os nothing fancy about our muffler.
It's a 400 x 400 mm x 1.8 m tall chipboard box made out 12mm MDF.
The inside is lined with a roll of 90 mm thick Rock woll acoustic and thermal insulation (it's the same stuff we used for the enclosure) which is held in place with a 200 mm diam cylinder of chicken wire.
The actual diameter of the chicken wire is a bit more than 200 probably closer to 225mm so that it compresses the insulation up against the side of the box.
The muffler does not need to be that long to be effective - I think half that length would probably be OK

BTW I would not recommend venting this muffler design inside the shed as quite apart from the fine dust the rock wool will release some rock wool fibres, more so in the initial bedding in period .

Thanks for that. Our mufflers are very similar, mine is 450mm square x 1350 high made of 16mm MDF and filled with acoustic batts and the top pipe fed into a 9" chicken wire cylinder wrapped with a sheet of Acoustiflex F8. It seems to work very well compared to the original bare Clearview but there is still a low rumble at he end of the exhaust pipe that I would like to get quiter.

Originally Posted by BobL

I expect there will be some dust, but what what say other other CVmax users?

I never had feedback suggesting that there was any noticeable dust in the exhaust except when leaks were present between the bin and the cyclone. A car which is only driven maybe once a month is parked under the exhaust of mine and there is never any evidence of dust on it except when the bin gets too full. Keep in mind this is in normal operation from machines, dust from sanders will pass some through but not all. I suggest that anyone who has dust in the exhaust take a really hard look and eliminate the leak that is causing it.

Originally Posted by BobL

I expect there will be some dust, but what what say other other CVmax users?

How big in total area is your enclosure escape vent?
In your install post back in 2013 I seem to recall you had a lot of trouble with the vent and I just looked at that thread again the photos of your ducting with hard 90º bends and other acute angles are a bit of a concern.
I suspect the flow rate is well down and that is perhaps why dust so much dust is depositing in the enclosure.
If the flow rate is less than desirable the cyclone also won't work properly and filter the intermediate dust out in the first place.
Have you opened up the air intakes to the machines to 6" ducting size?
Have you actually tested the flow rate with a hot wire anemometer and a test duct?

I probably should have commented more about on your install back then.
The note the post was 10pm on Dec 24 2013 and while I did see it at the time but with Xmas and holidays I never got back to it.

Bob,

Since that post the BMS has extended it's machine shop to double it's original size, which resulted in shifting the CV and new ducting to the machines. Most of the sharp bends have been removed but not all machines have been "opened up".

Here is the new enclosure approx 1200 x 1200 square, with this as the CV outlet. It can be seen here that there is dust in the exhaust air as it is sticking to the vent.

20160229_124552.jpg 20160229_124539.jpg

This is the muffler which consist of approximately 3metres of 10in A/C ducting wrapped in earthwool insulation.
20160229_124644.jpg
At the bottom of the muffler is a door to clean the exhaust vent when accidents happen, like today, the lid on the collection bin was not positioned correctly. There is a small gap between the lid and the handle, which caused an upflow in the collection pipe leading to the CV dumping into the muffler.

Next photo lid repositioned, vent cleaned and door secured. There is a small leak around the door which is resulting in the fine dust adhering to everything.
20160229_125213.jpg 20160229_125230.jpg

To give us an indication that the exhaust is blocked we have connected a manometer to the exhaust vent box.
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The red manometer is the exhaust pressure whilst the yellow one on the left is suction at the transition from square ducting into the rectangular CV inlet. It is not giving a true measurement of the static pressure at the moment as some of the water has evaporated. Originally the right hand tube was full with a hint of water in the left.

A couple of observations...

The pipe between the cyclone to the bin is way too long and will be causing the exhaust to carry dust.

Why are you exhausting into the sound reduction chamber?

Good here you have fixed up the ducting problems.
I wouldn't be that worried by that amount of dust sticking to the vent, especially as ours will be falling into a garden bed

Looking at the bottom of the muffler I can't see much of a way for the air to escape, unless it is now directed outside the enclosure through the vent?.
What does the piece of wood with the white edge do?
Is there a gap in the muffler on the side opposite to that piece of wood for the air to escape into the enclosure?

https://www.woodworkforums.com/attach...1&d=1456746684

Good hear you have fixed up the ducting problems.
I wouldn't be that worried by that amount of dust sticking to the vent, especially as ours will be falling into a garden bed

Looking at the bottom of the muffler I can't see much of a way for the air to escape, unless it is now directed outside the enclosure through the vent?.
What does the piece of wood with the white edge do?
Is there a gap in the muffler on the side opposite to that piece of wood for the air to escape into the enclosure?

Originally Posted by Chris Parks

A couple of observations...
The pipe between the cyclone to the bin is way too long and will be causing the exhaust to carry dust.

Chris,
There is height difference between the machine shed and the enclosure floors of about 1.5 metres. So it was a case of installing the CV low for the bin and have the suction ducting entering the shed at bench height and introduce extra bends to get it to the ceiling. Or install it high for good ducting and have a long drop pipe or provide some method to lift the bin to a short drop pipe!!!!!

Originally Posted by Chris Parks

A couple of observations...
Why are you exhausting into the sound reduction chamber?

???? Not sure of your question here. The exhaust of the CV is connected to the vent on the outside at the bottom of the enclosure, using 300mm a/c ducting gently stretched between those two points and wrapped in earthwool to reduce noise levels. We are located in the backyard of a church in a residential area.

Originally Posted by BobL

Good hear you have fixed up the ducting problems.
I wouldn't be that worried by that amount of dust sticking to the vent, especially as ours will be falling into a garden bed
Looking at the bottom of the muffler I can't see much of a way for the air to escape, unless it is now directed outside the enclosure through the vent?

Bob,
The smaller box section at the bottom the muffler is the backside of the vent. The door/flap was originally a screwed panel but after several overflows of the bin it was decided to make it easy to clean the vent box by hinging it and holding it closed with the toggles. So it is no longer sealed!
The vent came with flywire attached, we decided to leave it on so when accidents happen we didn't have a mess on the lawn!
With the old setup we ended up with about a metre of chips and dust between the original church sheds because we couldn't get in there to clean it up when the bin overflowed and the CV blew it out the exhaust.
Prior to installing the brick paving alongside the enclosure the dust blew into the lawn that was growing there, when we dug the lawn out in front of the vent there was about 50mm of compacted dust under the lawn for an area of about 300mm x 300mm. This was after about a year's operation.

Originally Posted by BobL

What does the piece of wood with the white edge do?

When we made a wiring change to the control circuit of VFD, that piece of ply was removed from the enclosure lining and not put back.
The dust coating everything in these photo's is the result of approx two months usage. We had a cleanup/busybee/BBQ just before Xmas.

20160229_125230.jpg

To shorten the distance between the bin top and the cyclone bottom how about a small stage and use a ramp to wheel the bin up onto the stage?

I don't have a cyclone, but would like to understand all this much better. I don't understand how the distance from the bottom of the cyclone into the bin affects anythng. By the time a dust particle reaches the bottom of the cyclone, isn't it effectively "out of the system" and then this extension piece is just the same as a taller bin?

As I said a lot to learn, but just trying to understand better.

Regards

Bauldy

I don't know if there are any absolutes on the hose length but there was discussion some years ago on this point and it was generally agreed that a long hose is detrimental to the performance of the cyclone. I suppose it could be surmised if a leak was present below the cone at any given time there is more dust in a long hose than a short one therefore more dust would get pulled back into the exhaust.

If that is not feasible then your guess is as good as mine as I know of no one who has categorically done any work to find out why. It was just a bunch of us bouncing ideas around and trying things to fix a few problems at the time. There is a CV forum if anyone wants to have a look though it does not get a huge amount of traffic.