152 New Patents

A novel class of aromatic polyester poly- carbonates is described. The polycarbonates are made by reacting an alkylene carbonate with an aromatic polyester polyol over a polycarbonate formation catalyst such as potassium stannate. In turn, the poiyol is made by esterifying a dibasic acid waste stream with an alkylene glycol to produce a polyester polyol which is sub- sequently used to transesterify recycled poly- ethylene terephthalate.

4475351

DUAL-FLOW CRYOGENIC FREEZER

An apparatus for cleaning hard surfaces and surface coverings such as rugs and upholstery material, consisting of a tank of cleaning fluid, an outlet line running to a cleaning head, a pump in connection with the outlet line, a vacuum motor with an inlet line recovering cleaning fluid through the cleaning head, filters in the tank in connection with the inlet and outlet lines, a stream cleaning the outlet filter and centrifuging the cleaning fluid in the tank separating out con- taminants leaving a body of cleaning fluid sub- stantially free of particulate matter to recycle whereby for example, a tank of six gallons of cleaning fluid can accomplish the effective cleaning effort for which would be required on the order of sixty gallons of uncycled cleaning fluid.

4468483

AROMATIC POLYESTER POLYCARBONATES FROM POLYOLS DERIVED FROM

RECYCLED POLYETHYLENE TEREPHTHALATE

Ernest L Yeakey, Michael Cuscurida assigned to Texaco Inc

P P Ho(CHlho(CHz)2OC(CHzhc-

f; -

u-

ii -0WHSXCHzM’C

\ / C--O(CHz)zOH

P s P R+(OCH2C-Oh,-C-0-(CHz-C-OhfrH

? ?

David J Klee assigned to Air Products and Chemicals Inc

Products to be frozen are conveyed through an insulated horizontal tunnel having a plurality of individual cooling zones, each equipped with a radial fan rotating in a horizontal plane. Cryogenic liquid refrigerant is sprayed into one or more of the cooling zones in the central region of the tunnel, upwardly into the rotating fans and the thus vaporized refrigerant caused to flow in a downward direction in a recirculating pat- tern into contact with the conveyed products by vertical partitions between contiguous zones. The vaporized refrigerant flows from the super- cold zone of liquid introduction beneath the ed- ges of the partitions in two directions, outwardly towards the opposite ends of the tunnel in sub- stantially equal amounts. The treated products thus undergo a continuously declining tempera- ture gradient from inlet to outlet of the tunnel as a result of direct heat exchange with refrigerant vapor in counterflow thereto from the supercold zone to the products inlet and concurrent flow of the vapor from said supercold zone to the pro- ducts outlet.

4477250

ASPHALT RECYCLE PLANT AND METHOD

David F Brashears, Emanuel J Elliott, Theodore G Butler assigned to Mechtron International Corporation