Abstract: A particle size classifier in which feed material composed of product and overs moves downwardly through a separator unit by the action of negative pressures created by a first air blower associated with the collection of product and a second air blower associated with the collection of overs. As the feed material moves downwardly, the product and the overs are separated with the product passing from within a screen unit to outside the screen unit and the screen unit preventing passage of the overs. Blowback air, applied to the screen unit from the outside cleans the cylindrical screen unit to permit continued passage of product through the screen unit.

Abstract: A catalyst having a high pore volume, high surface area porous silica support and a non-metallocene, Ziegler-Natta catalytic component incorporated on the silica support is provided for the production of polyolefins from .alpha.-olefins. The porous silica support is made up of silica gel particles having an average surface area of about 600 to about 800 m.sup.2 /g of silica and an average pore volume of about 2.5 to about 4.0 ml/g of silica. Preferably, the silica particles have an average surface area of about 650 to about 750 m.sup.2 /g of silica and an average pore volume of about 2.75 to about 3.25 ml/g of silica. Even more preferably, the silica particles have an average surface area of about 700 m.sup.2 /g of silica and an average pore volume of about 3.0 ml/g of silica. The catalytic component comprises a complex product of a transition metal halide and a metal alkyl which excludes cyclopentadienyl rings.

Abstract: A transition metal containing catalyst having a silica-support is provided for the production of polyolefins from .alpha.-olefins that can be converted to polymer films, preferably thin films of polyolefin, which have lower defects resulting from a decreased presence of silica-containing residues from the catalyst. The catalyst has a porous silica support component and a catalytic component which may include, but is not limited to, such materials as chromium, magnesium-titanium (Ziegler-Natta type) or metallocene compounds (Metallocene catalyst type). The porous silica component of the catalyst has an average pore volume of from about 2.5 to about 3.5 ml/g and a surface area of 200 to 400 m.sup.2 /g and preferably 250 to 350 m.sup.2 /g. The average pore diameter ranges from about 285 to about 700 Angstroms and preferably 500-700 Angstroms for porous silica components having surface areas of 200 m.sup.2 /g and preferably 285-400 Angstroms for porous silica components having surface areas of 350 m.sup.2 /g.

Abstract: A composition that provides improved chillproofing of beer and other beverages is disclosed. The composition comprises a silica gel reacted with a metal, said metal having the capability of being sorbed and desorbed from the silica gel in response to pH and concentration changes.