Environment International, Vol. 14, p. I, 1988 0160-4120/88 $3.00 + .00 Printed in the U.S.A. (c) 1989 Pergamon Press plc. All rights reserved.

NEW PATENTS

This Section contains abstracts and, where appropriate, illustrations of recently issued United States patents and published patent applications filed from over 30 countries under the Patent Cooperation Treaty. This information was obtained from recent additions to the Pergamon PATSEARCH ® online database in accordance with interest profiles developed by the Editors. Further information about Pergamon PATSEARCH ~ can be obtained from Pergamon Orbit InfoLine Inc., 8000 Westpark Drive, McLean, Virginia 22102 U.S.A.

Copies of complete patents announced in this Section are available from Pergamon Orbit InfoLine Inc. for $8 per copy. Payment with order is required. Orders outside North America add $2 for air postage. Order by patent number for Pergamon Orbit InfoLine only.

4741836

S L U D G E T R E A T M E N T P R O C E S S

Dal Jackman assigned to Jackman Enterprises Inc

A system for extracting moisture from sludge of the type handled by municipalities and indus- tries. The system involves the use of a feed line where the sludge is mixed with a chemical treating agent adapted to achieve flocculation. The sludge is conveyed, with or without some partial separation of moisture, to a progressive cavity continuous press for feeding of the sludge through the press. The press is of the type em- ploying a slotted or screened housing with an interior shaft so that the cavity of the press is defined between the shaft and the housing. The size of this cavity progressively decreases from the inlet end to the outlet end of the press whereby the mixture is gradually compressed as it moves through the press. Moisture contained in the mixture is thereby extracted through the housing which is designed to at least minimize passage of solids. A discharge chamber is located at the outlet end of the press for collecting the partially dehydrated mixture. Portions of the sludge may be diverted prior to entry into the progressive cavity continuous press and con- veyed to a separate collection site whereby a

sludge product with an intermediate moisture content becomes available.

4742009

M E T H O D F O R M O N I T O R I N G S T A C K G A S E S F O R U R A N I U M

A C T I V I T Y

Claude R Beverly, Harold G Ernstberger as- signed to The United States of America as represented by the United States Department of Energy

A method for monitoring the stack gases of a purge cascade of a gaseous diffusion plant for uranium activity. A sample stream is taken from the stack gases and contacted with a volume of moisture-laden air for converting trace levels of uranium hexafluoride, if any, in the stack gases into particulate uranyl fluoride. A continuous strip of filter paper from a supply roll is passed through this sampling stream to intercept and gather any uranyl fluoride in the sampling stream. This filter paper is then passed by an al- pha scintillation counting device where any radioactivity on the filter paper is sensed so as to provide a continuous monitoring of the gas stream for activity indicative of the uranium con- tent in the stack gases.

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