The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 12, 1988
Filed:
Aug. 07, 1986
Wolfgang Friemel, Heppenheim, DE;
Dr. Werner Freyberg Chemische Fabrik Delitia Nachf., Laudenbach, DE;
Abstract
In the fumigation of bulk materials such as grain with hydrogen phosphide (phosphine) the gas containing hydrogen phosphide is caused to circulate in a closed loop passing through the bulk material and past the zone of phosphine generation in pulses having a flow rate, duration and pulse intervals so designed that excessive or dangerous accumulations of gas are avoided and that optimum conditions for pest control are attained throughout the system as soon as possible. The intersticial gas of the commodity is changed by the circulation from 5 to 15 times within the period required for 90% of the available phosphine of the metal phosphide to be released. Each pulse has preferably a flow rate and duration sufficient to draw through the bulk commodity a volume of gas at least equal to the volume of the gas space above the bulk commodity and the pulse frequency is at least such that a complete change of intersticial gas in the bulk commodity takes place in less than the time taken for releasing 50% of the available phosphine gas of the composition while the intervals between successive pulses are about from 2 to 100 times as long as the duration of the pulses. Advantageously the flow rate is such as would produce a complete change of intersticial gas in 8 to 80 minutes.