Stupid extraction question....

[stuartpaul]

or is it?

I'm going to equip with 'proper' extraction this year and managed to get a very good deal from Rutlands on the 2 1/2 inch plastic 'trunking'.

All I need now is a good extractor to connect it all up to. Looking at 4 collection points, - none will be to a planer type machine so no big chippings going through this bit of the system (separate set up).

Axminster have this one at £175 and 1,200 cubic metres per hour http://www.axminster.co.uk/axminster-ax ... prod21167/

and this one at £160 and 2,000 cubic metres per hour http://www.axminster.co.uk/axminster-ax ... rod861355/

The second one seems a better deal as it's cheaper and shifts more air but I've been caught out on this sort of thing before.

So, - anyone know better about the physics of this stuff?

All help appreciated.

Thanks

Stuart

 

[Jacob]

Bigger is better as a rule, unless you really don't need the capacity. 100mm pipes too. If you have long runs at 2 1/2" you lose a lot of suck.

 

[doorframe]

Jacob..... what do you call 'long'?

My small system (yet to be installed) will only be 2" pipe, with the longest run being approx 10 metres. Is 10 metres 'long'?

Roy

 

[9fingers]

I'd agree with Jacob!
If you already have your 2-1/2" piping then I would plan out the locations to give pipe runs as short as possible with a radial scheme to the extractor rather than a serial line.
You may be better off with a manifold of 110mm soil pipe with spurs of 2-1/2" coming off that to each machine. Also try and keep the diameter of flexi pipe as large as possible and only go to small bore for as short a run as possible to any hand tools.
I have a 3hp extractor running a 110mm based pipes system which works very well but a 10 foot 1" bore flexy to my ROS is pretty ineffective even with all the other gates closed.

Bob
The physics of flow in pipes can get very complicated but in essence the flow drops greatly in smaller bore piping as a greater proportion of the waste becomes affected by friction against the sides of the pipe.

 

[9fingers]

Jacob..... what do you call 'long'?

My small system (yet to be installed) will only be 2" pipe, with the longest run being approx 10 metres. Is 10 metres 'long'?

Roy

I would not even think of using 2" over 10m. See my earlier reply for suggestions.
If you have a planer included in your collection needs, try and put the extractor next to that and use a hose that is the maximum the extractor can accept for the planer.
I don't know what is governing your use of 2" pipe but 110mm soil pipe bought from places like toolstation and delivered free is pretty cheap and easy to work with. 100mm gate can be glued into the inside of the pipe to give conversion to 100mm flexi pipe for your machines.

Bob

 

[Jacob]

Jacob..... what do you call 'long'?

My small system (yet to be installed) will only be 2" pipe, with the longest run being approx 10 metres. Is 10 metres 'long'?

Roy

Certainly is! It's more than 30 feet!

 

[doorframe]

I would not even think of using 2" over 10m. See my earlier reply for suggestions.
If you have a planer included in your collection needs, try and put the extractor next to that and use a hose that is the maximum the extractor can accept for the planer.
I don't know what is governing your use of 2" pipe but 110mm soil pipe bought from places like toolstation and delivered free is pretty cheap and easy to work with. 100mm gate can be glued into the inside of the pipe to give conversion to 100mm flexi pipe for your machines.

Bob

I got a good bundle of it + flowing T's and 90's off ebay a couple years ago. Cost peanuts. Seemed a good idea at the time. Think I've been trying to convince myself it's perfect for the job . Becoming obvious.... it's not!!

If I go with 4" soil and come off for each machine in a short run of 2", any suggestions where I can get cheap gate valves? I had a quick go at making some a while back, and although they worked they were very bulky.

Roy

 

[9fingers]

I would not even think of using 2" over 10m. See my earlier reply for suggestions.
If you have a planer included in your collection needs, try and put the extractor next to that and use a hose that is the maximum the extractor can accept for the planer.
I don't know what is governing your use of 2" pipe but 110mm soil pipe bought from places like toolstation and delivered free is pretty cheap and easy to work with. 100mm gate can be glued into the inside of the pipe to give conversion to 100mm flexi pipe for your machines.

Bob

I got a good bundle of it + flowing T's and 90's off ebay a couple years ago. Cost peanuts. Seemed a good idea at the time. Think I've been trying to convince myself it's perfect for the job . Becoming obvious.... it's not!!

If I go with 4" soil and come off for each machine in a short run of 2", any suggestions where I can get cheap gate valves? I had a quick go at making some a while back, and although they worked they were very bulky.

Roy

Ah I did wonder if it was a 'supply driven' choice. Maybe use a 110mm manifold and glue into this some swept bends from the 2" stash. I doubt that 2" gates are easily available and would persevere with refining a home made design. Say a polycarbonate or metal slider in an mdf based body.

hth

Bob

 

[studders]

I had the axminster 63mm kit. It was OK but it was obvious I was losing suction, even with a run of 2 or 3 metres. I upgraded to 110mm soil pipe and the difference was very noticeable. Only trouble really was the extortionate cost of underground fittings, which I'm still working on, and the reduction down to the machines outlet.

 

[eribaMotters]

Getting back to your choice of extractor. Big is best, not because of capacity, but because of performance.
I have always bought 2nd hand, statrting with Kity [nice small machine], Dewalt [bigger and good performance], Fercell [fine performer but top filter let to much dust through into the w'shop] and finally a Jet 1100 with fine cartridge filter. [£250 off e-bay easter 2010]. The latest combination is a joy to use. Copes well with 12" planer thickneser and the fine filter seems to block everything out.
Conclusion, buy the most powerful you can afford, 2nd hand is a sensible idea, and get a fine cartridge filter asap.

Colin

 

[9fingers]

Cheapest I have found is Toolstation. I tend to use MDF discs cut to a honeymoon fit in the pipe and the spigot on the machine to adapt to the different sizes.
The abrupt transition can cause a bit of turbulence but its a lot easier than a tapered transition.
Bob

 

[studders]

How do you deal with Blast Gates Bob? That's where I seem to have the biggest headache.

 

[9fingers]

Steve,
Can you expand on "How do you deal with Blast Gates" ?
I've got 100mm axi/rutland types but they are far from ideal.
I got them secondhand and would have been better off designing and making my own .... one day I will......
Currently I have one whistling somewhere I need to find and another that will not shut fully and needs taking out and cleaning.


Bob

 

[studders]

Bob, they, the blast gates* (mine are Axminster 100mm too) wont fit on/in to the 110 ducting directly but the difference is so small that getting a stiff enough shim has eluded me. The gates being tapered doesn't help either. I either can't get it in (space here for 'ooh er matron) or it's too loose and fall out.
Aside from shims I've also tried making some slits in the 110mm to compress it down, but that didn't work very well.
I know they do 110 - 100 adaptors but that starts getting expensive so I was looking for a simpler way.

*And yes, they do collect crud and won't close properly, even when installed upside down.

 

[9fingers]

Hi Steve,
I bought my 100mm gates secondhand and they have been glued into ends of 110mm pipe. As you rightly say there is a few mm clearance but the adhesive used looks like some form of foaming PU glue as used for woodworking. This has filled the gap perfectly and the combined assembly makes an ideal 110mm to 100mm hose conversion
They are stuck like bodily waste product to a fibrous bedding material and show no signs of coming apart even after several years.

hth

Bob

 

[Giff]

To fit the blast gates into the soil pipe use s/a neoprene strip. It's on ebay and starts at 1mm which makes 2mm when wrapped round. Gives a good friction fit.. giff

 

[studders]

Hi Steve,
I bought my 100mm gates secondhand and they have been glued into ends of 110mm pipe. As you rightly say there is a few mm clearance but the adhesive used looks like some form of foaming PU glue as used for woodworking. This has filled the gap perfectly and the combined assembly makes an ideal 110mm to 100mm hose conversion

Now, why didn't I think of an expanding adhesive? D'oh (slaps head)
Thanks Bob.

They are stuck like bodily waste product to a fibrous bedding material ......

hth

Bob

Very nicely put Bob, if I may say so.

 

[WellsWood]

Stuart
Sorry to shoot you down, but neither of those 2 machines you linked to are suitable for use with 2 1/2 " trunking. They are the the wrong kind of extractor (HVLP), and although both move large amounts of air both do so without making much in the way of vacuum, which is what you need to overcome the resistance inherant in small bore systems. They are designed to run with 4" pipe to machines with the same diameter outputs so that the airflow rates can be maintained - the minute you restrict their flow (by reducing pipe sizes for example) you can pretty much kiss goodbye to most of their effinciency, and therefore most of their ability to "extract" - as Bob has already noted.

If you already have a solution for large chippings from your planer etc. I would suggest a better solution would be to compliment this with a vacuum (HPLV) type extractor like this for example, which as well as being entirely suitable for a 2 - 2 1/2" ducted system (largely unaffected by long runs and stepping down for use with power tools etc), will also provide the much higher level of filtration required to make your efforts of any value.

 

[Jacob]

....

I got a good bundle of it + flowing T's and 90's off ebay a couple years ago. Cost peanuts. Seemed a good idea at the time. Think I've been trying to convince myself it's perfect for the job . Becoming obvious.... it's not!!..

If you have a lot of it you could use 3 or 4 in parallel perhaps? More like a "manifold" than a single pipe!

 

[doorframe]

If you have a lot of it you could use 3 or 4 in parallel perhaps? More like a "manifold" than a single pipe!

I've got about 2 metres of 4" flexi, which I was planning to come from the extractor house into the w/shop (The extractor will be in a small 6x4 shed next to the w/shop). I've got a 4" manifold which has about 4 2"outlets/inlets (I can add more). I was then going to distribute in 2" around the w/shop. I was planning on about 15 points around the w/shop.

As none of my machines has a hose connector larger than 2" I thought I may get away with this idea. I'll have to make a test piece to mimic the original idea and see what results I get. The soonest it will happen will be in the summertime so I'm not committed yet.

Roy