METHOD AND APPARATUS FOR PHOSPHINE FUMIGATION OF PRODUCT Russian patent published in 1997 - IPC

FIELD: storage of cereal product. SUBSTANCE: method involves directing phosphine bearing carrier gas through grain or similar product. Concentration of phosphine in carrier gas is within the range of 4-200 microgram of phosphine per liter. Gas flow directed through grain has constant linear speed and imparts speed to grain mass ranging between 0.5x10 10^-4 and 2x10 10^-4 m per sec. Grain mass is further fumigated by means of single gaseous fumigant source in storage having plurality of grain elevators. Gaseous fumigant source is communicated with gas supply pipeline, which is connected with gas inlet channels of elevators. Valve and diaphragm are positioned at each gas inlet channel and pipeline junction point. Each diaphragm is regulated so that pressure difference or pressure drop across diaphragm in elevator exceeds pressure difference or pressure drop across any other component of between gas source and hopper. Due to such construction of apparatus rate of gaseous fumigant flowing through grain elevators in storage is varied slightly only when valve between pipeline and elevator is opened or closed. Such insignificant variation of flow rate may be readily compensated by maintaining gas pressure in pipeline at constant level. EFFECT: increased efficiency and reduced production cost. 14 cl, 3 dwg