The HDS method is a modern and safe way to fumigate grain without entering grain bins or other confined space entry locations. Unlike solid phosphine fumigant, this system will allow the fumigator to add gas during the fumigation to ensure successful results.
Metal phosphides such as Phostoxin™ pellets and tablets were the main grain fumigants worldwide since the 1960s. Phostoxin was often used in many different types of grain structures from farm bins to large commercial operations. Cylinderized phosphine such as ECO2 FUME™ was introduced by FSS and BOC in 1999. It contains 98% CO2 and 2% PH3. A new way to fumigate large grain facilities was introduced in 2003, VAPH3OS and the Horn Diluphos System (HDS).
With the HDS system, there is no need to enter the bin or structure to seal or insert solid phosphine pellets, therefore no confined space or bin entry precautions are needed. The fumigant you are putting into the grain is completely gaseous. Because it is completely gaseous, there is no dust, spent material, or disposal once the fumigation is complete.
VAPORPH3OS is nonflammable once applied. Unlike metal phosphides, you are not waiting hours or days for an effective Rice Weevil concentration of phosphine to build up. The fumigation starts instantly. Accurate dosing to the gram occurs with the HDS. When the gas is applied, it creates a slight positive pressure which forces gas throughout the grain mass, aeration plenum, and through moist grain pockets.
The covered grain pile shown above was fumigated with the HDS machine. The “Circle Pile” is 900,000 bu./25,000 tons. The bottom skirt is sealed with 6 mil. plastic sheeting, tape, and sand. VAPORPH3OS is applied into the bottom aeration fans for several hours. Three recirculation systems are installed on the grain mass, forcing gas to reach equilibrium quickly. Monitoring lines are installed with metal piping probed into the grain mass throughout the structure. Readings are taken in real time with the advanced Fosfoquim™ monitoring equipment to ensure efficacy. When fumigating large structures outdoors, wind and weather are important factors. The structure above required applying add gas to one side of the circle pile to make up for gas movement inside the tarp. Fumigant gas can be moved by either rearranging the recirculation system from high concentration to low concentration, or by adding more gas to the low areas.