GB488418A - Improvements in or relating to fumigation - Google Patents

Abstract

488,418. Fumigating ; treating grain. GUARDITE CORPORATION, and CARBIDE & CARBON CHEMICALS CORPORATION. Oct. 2, 1936, No. 24057. Convention date, Nov. 18, 1935. [Classes 49, 81 (i), and 130] [Also in Group I] In the fumigation of organic products such as furs, tobacco or foods, e.g. oatmeal, in an enclosed chamber, this is exhausted to a pressure of not more than an inch of mercury, a gaseous fumigating mixture, one component of which is preferentially absorbed by the products is admitted until pressure is at least of the order of 5 lb., the mixture is removed from contact with the products, and conducted back to contact them at a point nearer to the original entrance of the mixture than is the point of removal. Mixtures of an inert gas such as carbon dioxide with ethylene oxide or methyl formate may be used containing, e.g. 9 parts carbon dioxide to 1 of ethylene oxide. A tank 1 is first evacuated by pump 6 discharging through oil separator 10 and vent 12. Fumigant is then admitted through lines 15, 5 and 4 from pressure vessel 14, which may be provided with heating means and is connected with a fumigant supply 18, until a pressure of about 5 lb. is reached. The gas can be recirculated by withdrawing it through the discharge orifice 19 and line 7 and pumping it back through separator 10 and lines 15 and 5. Alternatively, the tank may be re-evacuated to a pressure of, say, 1 inch, the fumigant being stored in vessel 14. A single stage compressor may be employed for this purpose. The compressed gas is then released directly into the chamber through lines 4. This cycle is preferably carried out in 5 mins. or less and repeated in 10 mins. A third method of passing back the gases is to follow method one but reverse the gas flow every few minutes, first closing line 7 and pumping the gases from the tank through line 5 and into the tank through line 9, and then closing line 9 and pumping gases out through line 7 and back through lines 15 and 5. Specifications 23121/06 and 23954/07, [both in Class 81], are referred to.