The Hacks-traction Project
Extraction System Drawings Sketches and Plans
- suitable for use with ~100mm ducting
- small, either fits in the loft or takes up minimal room in the workshop.
Most dust extractors seem to fall into one of two categories: high pressure (suction) but low flow rate (HPLV) or low pressure, high flow (LPHV). HPLV is most like a domestive vacuum or can format shop-vac, and is most suitable for hooking directly to a handheld powertool. They tend to use small diameter hoses (60-63mm) and have integrated filters. LPHV is better suited to large woodworking machinery or workshop-wide extraction systems. They tend to use larger hoses/ducts (100mm+) and have only coarse (but very large) filter bags, that let through the finer dust. They often need to be used in combination with an air cleaner / filter systems to keep the fine dust out of the air.
A relatively small LPHV system appears to be the best choice for the hackspace, as it won't take up too much room, won't be too loud but can create the high airflow needed for good chip extraction on the larger woodworking machinery
AC15fs: £210, 61-64dB, 360-600m^3/hr, for rooms up to 155m^3
AC400: £160, 69dB, up to 700m^3/hr
Scheppach HDA-14: £177, 50-60dB, 600-740m^3/hr
Dirty room extraction
needs to be suitable for painting and welding.
initial investigation by Mark:
From: https://www.hse.gov.uk/pubns/priced/hsg258.pdf (massive doc!)
I think we want about 1m/s air flow at the face of a positionable hood (similar for both painting and welding). Welding hoods are typically 250mm diameter, so that equates to about 0.05m^3/sec or 50ltr/sec or 176m^3/hr. looking at dedicated welding extractors, they start at about 200m^3/hr and go up to 1600m^3/hr for bigger ones.
200m^3/hr seems to be about mid-range for kitchen or bathroom extractor fans. We probably want to overspec it a bit, because their rated flow is probably with no ducting attached, and we might have quite a few meters of ducting to route the exhaust through the loft..