Dust Extraction - can this be improved.

[Freetochat]

I run a planer/thicknesser, saw/spindle and bandsaw on a small extraction system. The main pipework is one of the 63mm kits from Axminster. I use 100mm hose to connect into the pipework and 100mm hose to connect the pipework to an RDX1500 (Record) Dust Extractor. The spec. for the RDX 1500 is 53 l/s Free Airflow, 2500mm (WG) suction capacity with a 1000W motor. Not all dust/chippings are being collected, and I was considering whether the bore reduction was causing an airflow problem, or whether I was expecting too much from the RDX 1500. Any advice or information links would be appreciated.

Regards

John

 

[Noel]

The airflow is being impeded by the 100mm to 63mm reduction. If you can swap out the 63mm and replace with 100mm you see a big improvement. Think about it: 2 straws in a glass of water, one thick and one thin straw. Which will empty the glass quickest? Simple analogy but clearly illustrates that bigger is better, within reason.

Rgds

Noel

 

[Adam]

Its also to do with how long the restriction lasts for, 63mm for anything over 10-20 cm will have a large effect, wheras one final reduction just at the machine (to 63mm) will have less of an effect.

You can test this in the "drinking straw" analagy by taking a thick straw and narrowing it at just one end to the narrower diamater - you conitnue to get most of the benefit of the larger tube, - provided the narrowing doesn't last any significant distance.

Adam

 

[Woodythepecker]

John i am in the middle of setting up a dust extraction system for my son and over the last couple of weeks i have been doing a quite a bit of research (thanks Felderman). One website that most people will point you towards is www.billpentz.com What Bill Pentz does not know about wood dust and getting rid of it, is not worth knowing.

From what i have read, i would agree with Adam, you will find 100mm ducting a lot better.

Good Luck

Woody

 

[Adam]

In fact from memory, Bill Pentz site recommends that even 100mm cannot acheive the air movement neccasary unless you have a turbo charged extractor on the end of it.

I think he recommend 150mm pipe.

Adam

 

[Noel]

The Bill Pentz site has plenty of info but it's just tooo detailed for most of our applications. Lift the basics and get your system running. 5 & 6" ducts are ok (and are superior with a suitable blower) but have little application on our side of the Atlantic. Most extractors are 4" / 100mm ported and cyclones are rare in the home shop. 4" will work very well.

Noel

 

[Barry Burgess]

You need at least 100mm but if you read Bill's site he recommends starting with 6" reducing to 5" and finally 4"
I am at present completing running 110mm soil pipe around my garage but have used blastgates at each outlet so that I can control the flow.

 

[OLD]

Try connecting the record direct to the p/t all 100mm this will give you a indication of what to expect. if this is ok you may be able to rearrange pipe work to give 100 to p/t and 63 to b/s and saw/spindle etc

 

[ProShop]

Freetochat,
I'm not entirely sure that 53lts sec is really enough for a P/T.
But I agree with all the above posts in that 100mm (minimum) pipe is the way to go, and as Adam mentions any reductions needed for machines with less than 100mm are made right at the end.
Another often forgotten point to bear in mind is static pressure measured as PA, and not all manufacturers state this on their machines.

 

[PJ]

John, I remember talking to a technical guy from one of the companys who make these small vacuum type machines and he advised that the 63mm ducting would preform better on these small waste producing machines and only consider going up to 100mm if a using a high waste producing machine to stop blockages. I think for your best performance you should keep the machines creating small waste on the small bore pipe and just connect the p/t to the extractor using a 2m length of 100mm flexible pipe.
The information on Bill Pentz's site is top notch, in fact I have built one of his cyclones, budget blowers and 6" ducting and have never looked back, but it is based on large air movement with a relatively low vacuum (12-20"wg) as apposed to your's with small air movement but a high vacuum. The 2 approaches are different and do not mix, but you need both types for the best extraction within the workshop, ie chip extractor for planer/ tablesaw and shop vacuum for power tools etc.

Hope this helps

Philip

 

[Barry Burgess]

The 2 approaches are different and do not mix, but you need both types for the best extraction within the workshop, ie chip extractor for planer/ tablesaw and shop vacuum for power tools etc.
Philip

I have built 2 mini cyclones for my vacuum cleaner based system and they work far better than the vacuum on their own The vacuum based systems work better on power tools and belt sanders but are not so good on router tables and planers etc.
The vacuum systems also fail when you are trying to collect from above & below the table at the same time. It was cheaper to start with using 2 vacuums(bought on EBay for £25 each W2000) than going to the expense of buying a 2hp dust extractor £199 For Bill Pentz systems the minimum requirement to get the flow rates is a 2HP blower.
In the end I decided that the only way to go was to run 4" piping and build a full cyclone but it takes time and the mini system is just coping.
Hope this helps.