The bubble method of fumigation differs from traditional methods in three critical ways.
a. The materials are sealed in an airtight flexible envelope which does not allow air to enter or escape.
b. A partial vacuum is pulled so that less air will be contained within the materials.
c. When the gas/air mixture is admitted into the Bubble through the power unit, lethal gas goes immediately to the center of the materials being fumigated. This shortens the time for a complete kill because the molecule exchange of gas and air happens almost immediately and equilibrium is attained within the Bubble. With tarp fumigation, equilibrium of the gas mixture is almost never reached; unequal levels or layers of concentrate affect the success of the total job - high concentration of gas at the bottom and less at the top.
The Bubble's construction allows the use of traditional gases (e.g., methyl bromide) as well as inert gases (e.g., carbon dioxide and argon). Adaptation for use with inert gases was done in England and Germany by Colin Smith of Rentokil. By increasing the temperature of the OD2 in the Bubble to 100.40F, he has reduced the time of fumigation from 14 to 2 days, and hopes to reduce it still further. He uses a 60% concentration of C02 in air.
For a list of B & G distributors, write B & G Equipment Company, PO Box 130, Plumsteadville, PA 18949 (215/7668811).