Method and apparatus for controlling the drying and cooling of field-harvested seeds in storage

A grain drying 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 including:

• means for introducing atmospheric air into the plenum chamber;
• heating means for adding heat energy to the air in the plenum chamber;
• means for sensing the temperature of air in the plenum chamber;
• means for sensing the temperature of air as it exhausts the bin;
• thermostat means for controlling the operation of the heating means;
• and
• differential temperature control means adapted to override the thermostat means controlling the heating means and thereby inactivate the heating means when the temperature difference between the drying air in the plenum chamber and the air exiting the bin is greater than a predetermined amount.

In a grain drying bin of the type having a first chamber formed in the lower part thereof, a gas-pervious floor forming the top of said first chamber, and a second chamber formed between the grain and the top of the grain bin, one of said chambers being an exhaust chamber, the improvement comprising:

• means for introducing atmospheric air into the plenum chamber;
• heating means for adding heat energy to the air in the plenum chamber;
• means for sensing the temperature of air in the plenum chamber;
• means for sensing the temperature of air in the exhaust chamber;
• thermostat means operating in response to the temperature of air in the plenum chamber for controlling the operation of the heating means by activating the heating means when the temperature of the air in the plenum chamber is below a predetermined temperature and inactivating the heating means when the temperature of the air in the plenum chamber is above said predetermined temperature;
• differential temperature control means operating in response to the difference in temperature between the air in the plenum chamber and the air in the exhaust chamber for overriding the activation of the heating means by the thermostat means when said difference in temperature exceeds a predetermined temperature amount to thereby inactivate the heating means only while the difference in temperature exceeds said predetermined temperature, said differential control temperature means having no overriding effect on the thermostat means when said difference in temperature does not exceed said predetermined temperature.

In a grain drying bin of the type having a first chamber formed in the lower part thereof, a gas-pervious floor forming the top of said first chamber, and a second chamber formed between the grain and the top of the grain bin, one of said chambers being a plenum chamber and the other of said chambers being an exhaust chamber, the improvement comprising:

• means for introducing atmospheric air into the plenum chamber;
• heating means for adding heat energy to the air in the plenum chamber;
• electric circuit means for controlling the heating means;
• means for sensing the temperature of air in the plenum chamber;
• thermostat means for opening or closing the circuit means in response to the temperature of air in the plenum chamber to thereby activate the heating means as long as the air in the plenun chamber is below a predetermined temperature;
• and
• differential temperature control means set at a predetermined temperature differential between the plenum air and the exhaust air for automatically opening the circuit means of the heating means when the predetermined temperature differential is exceeded and closing the circuit means when the differential temperature is less than the predetermined temperature differential setting.

In a grain drying bin of the type having a first chamber formed in the lower part thereof, a gas-pervious floor forming the top of said first chamber, and a second chamber formed between the grain and the top of the grain bin, one of said chambers being a plenum chamber and the other of said chambers being an exhaust chamber, the improvement comprising:

• means for introducing atmospheric air into the plenum chamber;
• heating means for adding heat energy to the air in the plenum chamber;
• means for sensing the temperature of air in the plenum chamber;
• means for sensing the temperature of air in the exhaust chamber;
• first thermostat means operating in response to the temperature of air in the plenum chamber for activating the heating means so long as the air in the plenum chamber is below a predetermined temperature;
• and
• second thermostat means operating in response to the temperature of air in the exhaust chamber for further controlling the heating means by automatically overriding the first thermostat means by preventing the operation of the heating means when the temperature of the air in the exhaust chamber is below a predetermined temperature, said predetermined temperature of said first thermostat means being higher than said predetermined temperature of said second thermostat means.

A process for curing seeds comprising:

• placing uncured seeds in a closed environment;
• adding atmospheric air to one point of the closed environment, and allowing air to exit at another point in the closed environment;
• maintaining the addition of atmospheric air within specified quantities;
• measuring the temperature of the air at the point of entry of the atmospheric air and at the point of exhaust from the closed environment;
• adding heat to the entering atmospheric air only when the temperature difference between the entering air minus the exiting air is less than a predetermined amount;
• controlling the amount of such heat being added to thereby always maintain the temperature of the exiting air cooler than the temperature of the entering atmospheric air;
• and
• continuing the addition of atmospheric air and controlling the addition of heat to the atmospheric air until a desired equilibrium moisture has been achieved in the stored seeds.

A process of drying uncured seeds comprising the steps of:

• placing uncured seeds in a closed environment;
• adding atmospheric air to one point of the closed environment, and allowing air to exit at another point in the closed environment;
• determining the temperature of the air at the point of entry into the seeds;
• determining the temperature of the air at the point of exhaust from the seeds;
• adding heat to the entering atmospheric air only when the difference between the temperatures of the entering air minus the exiting air is less than a predetermined amount required to achieve a desired equilibrium moisture in the stored seeds;
• and
• controlling the amount of such heat being added to thereby always maintain the temperature of the exiting air cooler than the temperature of the entering atmospheric air.

In a grain drying bin of the type having a first chamber formed in the lower part thereof, a gas-pervious floor forming the top of said first chamber, and a second chamber formed in the top of the grain bin, one of said chambers being a plenum chamber and the other of said chambers being an exhaust chamber, the improvement comprising:

• means for introducing atmospheric air into the plenum chamber;
• heating means for adding heat energy to the air in the plenum chamber;
• means or sensing the temperature of the air in the plenum chamber;
• means for sensing the temperature of the air in the exhaust chamber;
• and
• differential temperature control means operating in response to the difference in temperature between the air in the plenum chanber and the air in the exhaust chamber for activating the heating means when the result of the temperature in the plenum chamber minus the temperature in the exhaust chamber is a predetermined amount or less, and deactivating the heating means when the result of the temperature in the plenum chamber minus the temperature in the exhaust chamber is greater than said predetermined amount.

In a grain bin of the type having a first plenum chamber formed in the lower part thereof, a gas-pervious floor forming the top of said first chamber, and a second exhaust chamber formed in the top of the grain bin, the improvement comprising:

• means for bringing atmospheric air from the outside of said bin into said plenum chamber and causing said air to move successively from the outside of the bin, through the plenum chamber, through the floor, through the grain, through the exhaust chamber and out of the exhaust chamber to atmosphere;
• heating means for adding heat energy to the air in said plenum chamber;
• means for sensing the temperature of air at a first point prior to the entry of such air into the grain;
• means for sensing the temperature of the air at a second point after it has passed through the grain in said exhaust chamber;
• and
• differential temperature control means operating in response to the difference in temperature between the air at the first point and the air at the second point for activating said heating means when the result of the temperature at the first point minus the temperature at the second point is a predetermined amount or less, and for deactivating said heating means when the result of the temperature at the first point minus the temperature at the second point is greater than said predetermined amount.

A process of drying and preserving seeds, said seeds being in a bin having heating means and means for forcing air from outside of the bin into a plenum chamber in the lower part of the bin, said heating means being disposed in said plenum chamber, said plenum chamber being covered by a floor pervious to gas flow, said process comprising the steps of:

• introducing atmospheric air into said plenum chamber;
• determining the temperature of the incoming air at a first point prior to its entry into the grain;
• determining the temperature at a second point of exhaust air leaving the grain;
• inactivating said heating means when the temperature of the air at the first point minus the temperature at the second point of the exhaust air is greater than a pre-selected amount;
• and
• controlling the amount of heat from said heating means always to maintain the exhaust air temperature at the second point cooler than the inlet air temperature at the first point while the grain is curing.

A process of drying uncured seeds comprising the steps of:

• placing uncured seeds in a closed environment;
• adding atmospheric air to one point of the closed environment, and allowing air to exit at another point in the closed environment;
• determining the temperature of the entering air prior to the entry of such air into the seeds;
• determining the temperature of the air exiting from the seeds;
• adding heat to the entering atmospheric air only when the difference between the temperatures of the entering air minus the exiting air is less than a predetermined amount required to achieve a desired equilibrium moisture in the stored seeds;
• and
• controlling the amount of such heat being added whereby the temperature of the exiting air is cooler than the temperature of the entering atmospheric air.