Pressure reducing exhaust method and structure for ventilated grain bins

A push-pull air movement apparatus including a grain storage bin of the type having a plenum chamber formed in the lower part thereof and a gas-pervious floor forming the top of the plenum chamber for enhancing the movement of air through grain stored within said apparatus comprising:

• a grain storage bin;
• an intake fan means for pushing air through the grain, said intake fan means connected to the bin and in fluid communication with the stored grain, said intake fan means including a plurality of relatively high speed intake fans distributed about the wall of the plenum chamber;
• an exhaust fan means connected to the bin for pulling and exhausting at least as much air volume from the stored grain as the intake fan means inserts, said exhaust fan means including a plurality of relatively large volume, low speed exhaust fans distributed about the top wall portion of the grain storage bin;
• said grain bin having a base, a sidewall connected to said base, a roof connected to said sidewall and an opening in an upper portion of said sidewall leading to the grain storage portion of said bin;
• a downwardly inclined cylindrical housing attached to said upper portion of said sidewall encompassing said opening;
• said large volume low speed exhaust fan means attached to and disposed within said cylindrical housing for pulling a large volume of air from the inside of the grain bin;
• a plurality of perforated baffle means extending transversely across said opening for allowing said large volume of air to pass therethrough but preventing grain from passing therethrough, said baffle members extending upwardly and outwardly from said sidewalk to retain the grain within the confines of the grain storage portion of the bin;
• and
• means forming a closeable probe opening on the cylindrical housing.