Thread: What speed are you running your CV1800 at: 50Hz, 60Hz or 70Hz?

Originally Posted by bobl

reminds me of the member using a router i waved the spl meter showing over 90db in front of, and he said "s'ok i've taken my hearing aids out"

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................... : ~}

Originally Posted by NeilS

If I was starting from scratch now I would design a DE system for our Shed that included your blast gates, Chris... a solution to some of the issues that we have been discussing here that is highly suited to community sheds, IMO.

When funds permit, we might progressively retrofit.

The other thing worth considering is improved ventilation. At the mens sheds I've visited even those with decent DCs there still seems to be continual pall of fine dust generate by power tools. This is why I continually push ventilation. A second hand swampy acting as a ventilator can be had for relatively little money. They use relatively little power and they don't make that much noise.

Similar to bob, on my 5hp 3 phase dust collector I use the pot on the VFD to dial the hz up and down dependant on what i'm doing and whether or not I want to bother the neighbours. Using the potentiometer on the VFD you can dial the hz up and down on the fly either when it is running or before starting as required or just leave it at a particular value.

Originally Posted by BobL

The other thing worth considering is improved ventilation. At the mens sheds I've visited even those with decent DCs there still seems to be continual pall of fine dust generate by power tools. This is why I continually push ventilation. A second hand swampy acting as a ventilator can be had for relatively little money. They use relatively little power and they don't make that much noise.

That is directly opposite to my experience. At our local shed and before the system was installed the asthma sufferers had to leave the shed and now they don't suffer at all. That could also be because we designed in to the system over the bench hoods that can be brought close to the work and we recommend all sheds do the same when planning the DE system. Robertson planned to take that one step further with a hood that sits on the bench and it can be placed where the work is being done but it is big enough to put small pieces in when sanding. It is totally moveable and removeable as needed.

Originally Posted by BobL

The other thing worth considering is improved ventilation. At the mens sheds I've visited even those with decent DCs there still seems to be continual pall of fine dust generate by power tools. This is why I continually push ventilation.

The original occupants of our main building was TAFE for their pottery classes and they left us with three very large extractor ceiling fans (3ph/high volume) with three equally large hoods that sat over their kilns, two of which are still working. This is the workshop area that is mainly used for our hand power tool... so that is a bonus (along with the 3ph wiring), but getting them turned on when needed ~*~*~*~*~*~*~*~ and off when done, particularly at the end of a Shed session (they are very quiet) is, as you might expect, another matter.

Anything left on/running is an issue for our insurance should something go wrong. One of our members has the task of checking that everything is off at the end of a session and he does a good job of that... but, if he doesn't have his hearing aid on...

Originally Posted by hurcorh

Similar to bob, on my 5hp 3 phase dust collector I use the pot on the VFD to dial the hz up and down dependant on what i'm doing and whether or not I want to bother the neighbours. Using the potentiometer on the VFD you can dial the hz up and down on the fly either when it is running or before starting as required or just leave it at a particular value.

Thanks, Hurcorh.

That capacity to dial the speed up and down in your own workshop to suit yourself and the task is ideal.

I expect at the Men's Shed it will be more a case of set and forget.

Originally Posted by Chris Parks

... we designed into the system over the bench hoods that can be brought close to the work

Chris, have you, or they, posted any pics of those?

Originally Posted by Chris Parks

That is directly opposite to my experience. At our local shed and before the system was installed the asthma sufferers had to leave the shed and now they don't suffer at all. That could also be because we designed in to the system over the bench hoods that can be brought close to the work and we recommend all sheds do the same when planning the DE system. Robertson planned to take that one step further with a hood that sits on the bench and it can be placed where the work is being done but it is big enough to put small pieces in when sanding. It is totally moveable and removeable as needed.

I've been to over 30 mens sheds and have seen some very surprising things including the following.

A large mens city shed (200 members with up to 40 members attending at any one time) plumbed using 4" ducting and 2 x 3HP DCs. There were also 6 big wall fans, fans, a big swampy and two large roller doors. I was trying to convince them to put in 6" ducting so I left my particle counters there for a week but the dust levels never got above ~30 µg/m^3. The one thing they did do was have their 3 sanders on a veranda, but all their TS and thicknesser/planers were inside.

At a very large country shed, with a large swampy, large roller doors at each end, 6" ducting on most bigger machines, but only 4" on the rest, and their 6 bag 10HP DC was located inside the shed next to one of the roller doors. They also had a lot of power tool users not connected to anything for which I recommended downdraft benches and hoods. Again I left the particle counters there for two weeks and with the Swampy off the levels quickly got up over 100 ug/m^3 but if they were using their swampy, <20 ug/m^3. I cannot argue with these figures.

Now I admit these guys have to wear jumpers in winter as it tends to be rather chilli in these sheds but a big DC is still going to suck lots of air into a shed anyway.

In some cases where the shed is bIg enough and with few operators, not even a swampy is needed if the openings are big enough. A mate of mine has a WW business - sole operator, 140m^2 with 5m high roof (700 m^3), full height roller doors at each end.. His machines are connected by 6" ducting to a Felder 3HP 2 bag DC located aside the shed near the back roller door. Particle counter runs for a week - hardly any difference compare to outside.

I've also done dust measurements in about 20 DIY sheds and it's these Sheds that seem to have bigger problems. Even though there's usually only one operator they tend to be much smaller and have zero or minimal ventilation. The worst shed was only 24m^3 which the operator kept the doors and windows closed because he didn't want noise complaints from the neighbours. He mainly used power tools and although he had a shop vac it was not sealed and was spewing forth a constant stream of invisible fine dust. This is the guy who needed and externally venting DC.

Large sheds allow any dust to rapidly diffuse into the shed volume and if those sheds slo have a roller door and eg a personal door on the opposite wall, operators in these sheds will will experience a much lower overall exposure.

I am somewhat skeptical of what people with breathing difficulties report about dust levels as I think some of their reactions are psychosomatic. If they see sawdust or even just think something is making dust and they react to it, but if they see no dust or don't think too hard about it they may not even realize they are being exposed. Its bit like people who measure air flows with a wet finger.

One one retirement village mens shed I visited there were two members who were concerned about the dust levels so the shed committee called me in to advise. It was a smallish long, low ceiling shed with a single double door entry. They had about 25 members but had at most half a dozen members attending at any one time although about half of these were often sitting or standing around telling other how to do what they were doing - I have no problem with that as I do that all the time - I say this to indicate there was not much dust being made. They must have a had a fat wallet because they had a full complement of WW gear all crowded into a small space and their primary output was toys ie small stuff. They had all 4" ducting connected to several 2 and 3HP DCs located inside and although the doors were open there was not that much chance of adequate ventilation

I did some measurements but the dust levels were barely above the outside background. I spoke to the two complainers, or rather these two guys cornered me and chewed my ear for half an hour. I showed them the measurements which reassured them. Despite the measurements I left recommendations for a larger external DC and 6" ducting but as far as I know they are still talking about it. I reckon they have a greater risk from an overcrowded workshop than dust.

The mens shed I used to attend there was one member who constantly complained about dust levels before we got the Clearvue, he said it affected his asthma and that limited his shed involvement. When the Clearvue was installed he was coming in more often and was very happy, no problems he said, but I caught him a number of times using a sander and bandsaw without the blast gates open.

Its a bit like me with MDF. I only have to see some MDF and I think I smell BBQ sauce, which is what happened just before I lost my sense of smell from working outside with MDF. Apparently this also happens to some people who lose their sense of smell with Covid. I also have sporadic asthma but it doesn't seems to be triggered by exposure too wood dust.

I found the dust versus time data for another large country shed, NO swampy.
An average of about a dozen members attending at any one time - lots of standing around and chin wagging.
Big Roller doors at each end, only 4" ducting and DCs were a mix of 2/3HP DCs all INSIDE the shed.
There was visible dust over most things but below shows what was actually in the air.

The data is for a Friday, Sat, Sun, Mon, and Tuesday morning.
Sundays they are closed hence the lack of dust and it shows the typical country background ie <~5 ug/m^3 PM2.5 (red dots)
Except for several short bursts on tuesday, all other times the dust is <50 ug/m^3
Even on the worst day (Tuesday) where there are numbers of higher peaks, including one over 100, the average PM2.5 exposure on that day was only about 11 ug/m^3
The average for most capital cities in Australian is between 16 and 19 ug/m^3

All these guys needed was a swampy to knock the tops of those peaks otherwise this is not what I would call a problem shed.
I believe that have since installed a large (>10 HP multi bag) DC which they had donated to them - I think it's outside their shed.




Attachment 506552

At the other end of the spectrum (or the worst) was a large (250 m^2) metro shed (250 members) where they had a smaller machine room (~30m^2) with a number of thicknesser/planers/sanders serviced by several 3HP DCs located inside that room. I stopped taking readings after about 15 minutes with PM2.5s of >150 ug/m2 often as high as 500ug/m^3. They didn't really need me to come and check this as the room air was rather hazy and operators were coming out of there after 15 minutes with very itchy eyes - most wore masks.

Originally Posted by NeilS

Chris, have you, or they, posted any pics of those?

No, the overheads at Helensburgh are on a boom arm with a length of flex and a bell mouth on them and an activation switch for the cyclone. I have not seen the one at Robertson because it had not been built. It was a small enclosure which the overhead bell mouth was attached to. The rough idea was a 150mm hole in the back of it and some battens surrounding the hole with a rebate in the batten facing the box, the 150mm bell hood on the overhead was slipped into the retaining battens if needed.

What is a swampy and why is it relevant?

Originally Posted by Chris Parks

What is a swampy and why is it relevant?

Evaporative air-con.

Neil,

Some further info:
Drop Saw ........4,850 FPM and 906 CFM wide open ... longer flexy but few restrictions. Very good dust capture.
Drill Press ....... 5,200 FPM and 971 CFM wide open ... long run but no flexy and few restrictions.
Drum Sander ... 4,550 FPM and 850 CFM Hood a bit close to the drum, so restricted a little, but dust capture is great.
Band Saw ....... 4,300 FPM and 803 CFM Three 90 mm lines, so restricted somewhat ... but low blade and dust speed means dust capture is excellent.
Table Saw ...... 5,100 FPM and 952 CFM Very good dust capture.
Linisher .......... 4,650 FPM and 868 CFM Hood a little too close to the belt, so restricted a little, but dust capture is great.

Originally, I had intended to open out some of the restrictions, but dust capture is generally so good that laziness took over and they all remain unchanged. It works!

Originally Posted by John Samuel

Neil,

Some further info:
Drop Saw ........4,850 FPM and 906 CFM wide open ... longer flexy but few restrictions. Very good dust capture.
Drill Press ....... 5,200 FPM and 971 CFM wide open ... long run but no flexy and few restrictions.
Drum Sander ... 4,550 FPM and 850 CFM Hood a bit close to the drum, so restricted a little, but dust capture is great.
Band Saw ....... 4,300 FPM and 803 CFM Three 90 mm lines, so restricted somewhat ... but low blade and dust speed means dust capture is excellent.
Table Saw ...... 5,100 FPM and 952 CFM Very good dust capture.
Linisher .......... 4,650 FPM and 868 CFM Hood a little too close to the belt, so restricted a little, but dust capture is great.

Originally, I had intended to open out some of the restrictions, but dust capture is generally so good that laziness took over and they all remain unchanged. It works!

Thanks, John, for that update.

Also had another look at your ports posts.