You could try adapting the principles of depth filtration. Google it up and you'll probably find something which tells you how far to space your screen decks.

At first sight I'd say that your top deck aperture should pass everything but also force the woods to travel flat across the lower deck so they won't pass the holes which you have sized for the plastic bits. It's going to be experimental so allow for about 10mm adjustment of the deck spacing which will involve lampack.■

well.......you could try going to MAJOR WIRE INDUSTRIES province of Quebec

- They have very special stainless steel wirecloth sections in various aperture shapes....example: square, diamond, s shape, diamond shape, and others....these are self cleaning and may suit your wish list somewhat better than normal woven wire cloth

- You may look at air separation by specific density, heavies and lights

- you may look at sink float, density separator devices.....by specific gravity of the different materials. ■

Originally Posted by mike1020

Is anybody aware of any screens that can be used to separate materials by shape? we wish to separate long thin shards of wood from plastic chips aroun 3-4mm diameter. Wood tyically "cylinder" shaped 3-4mm diameter, 8 to 12mm length

Thanks

You may want to try the General Kinematics Light/Heavy seperator or Destoner as it would allow the plastic chips to seperate from the "cylinder" pieces of wood. They are commonly used for applications of this sort.

www.generalkinematics.com

Best Regards,

Todd ■

If there is a difference in size between the plastic chips (I guess you mean the extruded pellets?) and the wood parts, a gyratory screener might be useful? At Rotex, we have supplied gyratory screeners to many plastic manufacturers to take out the dust and the longs from the plastic pellets. Rotex gyratory screeners have no vertical component in the motion, i.e. that wood parts will remain flat on the screen surface. The screen surface could be a perforated plate for example.

If you think that this might be an usefull option, just send me your details so I can forward to the responsible sales representative in your area. ■

Hmmmmm....well all the ideas have merit so far.

We also have tried successfully, whilst playing with wirecloth openings and types of media, be it, flat stainless light guage perf plate, or wirecloth to accomplish some interesting separations.

for example: after much failure with standard wirecloth, we successfully separated cryogenically frozen car tire pieces, which had been frozen, then quickly dropped into a HIGH SPEED GRINDER to blow them apart and separated the small granules in a fine round hole opening, from the wire birds nests ALSO created in the feed by the grinder as overs and separated the FABRIC cord also.....but, had to come up with a nice smooth surface, nicely , tightly butted up together so as to not SNAG stuff while shaking down the length.

We have in fact had success, removing wood elongates from chips with pick of the right wirecloth opening and a good STRONG CIRCLE stroke on the vibrating screen shaker. It is do-able, just need some patience.....ya know.........if at first you don't succeed.......try try....etc. ■

I invented a shape separator many moons ago that might suit your problem.

http://www.wipo.int/pctdb/en/ia.jsp?...5&DISPLAY=DESC

If you wanted to send me a sample, I might be able to run a few tests for you.

Apart from that, and in the absence of any further information, I would consider air tables.

Good luck. ■

Electrostatic separation might be worth considering too. I see there is a link about that at the bottom of the page in the 'similar threads' section. ■