Grain drying system

A method of drying grain stored in a grain bin having a drying fan for forcing unconditioned natural air upwards through said grain comprising the steps of:

• connecting a master control unit to the drying fan;
• inputting a desired grain equilibrium moisture content into the master control unit;
• hanging at least one relative humidity sensor cable assembly in the bin in which grain is to be stored, said relative humidity sensor cable assembly including a support cable, a pair of wires extending along the length of the support cable, and a plurality of relative humidity sensors mounted in vertically spaced apart relation on the support cable and communicatively coupled to the pair of wires, each of the plurality of relative humidity sensors having a rigid support member disposed adjacent thereto and being enclosed by a cover that surrounds a portion of the support cable, a portion of the pair of wires, the relative humidity sensor, and the rigid support member, the support cable and the pair of wires passing continuously through the cover to extend from each end thereof;
• filling the bin with grain, after hanging the at least one relative humidity sensor cable assembly therein, to a level such that said plurality of relative humidity sensors are surrounded by grain in the bin;
• selectively determining a set of out-of-grain conditions, including an external temperature and an external relative humidity of air outside the grain bin;
• selectively determining a set of in-grain conditions, including an in-grain relative humidity of the air surrounding the grain surrounding each of said relative humidity sensors respectively;
• communicating the set of out-of-grain conditions and the set of in-grain conditions to a master control unit;
• and
• selectively operating the drying fan depending on an analysis of the set of in-grain conditions and the set of out-of-grain conditions, to dry the grain to the desired grain equilibrium moisture content.

A grain drying system for a grain bin holding grain in a plurality of vertically spaced zones, comprising:

• a grain bin fan selectively operable by a primary controller to blow air from outside the grain bin up through the grain held in the grain bin to drive a moisture content of the grain to a selected grain moisture content;
• a relative humidity sensing cable assembly comprising a first flexible support cable having a plurality of relative humidity sensor assemblies mounted thereon in spaced apart relation and a pair of electrical conductors extending along the length of the relative humidity sensing cable assembly, the first support cable vertically supporting the relative humidity sensor assemblies against downward movement caused by a downward flow of grain contacting the relative humidity sensor assemblies, said relative humidity sensing cable assembly hanging within the grain bin and extending into a grain storage area of the grain bin in which grain is to be stored such that said relative humidity sensor assemblies extend in vertically spaced relation in the grain storage area of the grain bin such that grain stored in said grain bin to a level above one of said relative humidity sensor assemblies extends completely around said relative humidity sensor assembly, each of said relative humidity sensor assemblies including a relative humidity sensor secured within a tubular enclosure surrounding said relative humidity sensor, said first support cable and said first pair of electrical conductors with said first cable and said first pair of electrical conductors extending continuously through said tubular enclosure to extend from each end thereof, said relative humidity sensor being in electrical communication with said first pair of electrical conductors, and said tubular enclosure having at least one opening extending therethrough extending in communication with said relative humidity sensor;
• each of said relative humidity sensors sensing an in-grain relative humidity value of air surrounding the grain surrounding said respective relative humidity sensor;
• an external condition sensing assembly, mounted outside of the grain bin for determining an external air temperature and an external relative humidity value of air outside of said grain storage area of the grain bin;
• means for communicating the in-grain relative humidity values via said first pair of electrical conductors, the external relative humidity value and the external air temperature to said primary controller;
• said primary controller performing a comparison of the in-grain relative humidity values to the external relative humidity value and the external air temperature and activating said fan when one of a selected set of rules relating to said comparison are met.

A relative humidity sensing cable assembly for use in association with an in-bin grain drying system for grain in a grain bin, said cable assembly comprising:

• a support cable having a plurality of relative humidity sensor assemblies mounted on the support cable in spaced apart relation along its length and a conductor member extending along at least a portion of the length of support cable and between each of the plurality of relative humidity sensor assemblies;
• said support cable having a first end securable within said grain bin above a grain storage area of the grain bin in which grain is stored;
• said support cable sized to hang into a plurality of vertically spaced zones of grain held in said grain storage area such that each of said relative humidity sensor assemblies extends in a different one of the plurality of vertically space zones;
• each of said relative humidity sensor assemblies including a relative humidity sensor secured within a tubular enclosure surrounding said relative humidity sensor, said support cable and said conductor member and having at least one opening extending therethrough in communication with said relative humidity sensor, each of said relative humidity sensors being electrically coupled to said conductor member, and said support cable and said conductor member passing through the tubular enclosure to extend from each end thereof;
• each of said relative humidity sensors sensing an in-grain relative humidity value of air surrounding grain surrounding said respective relative humidity sensor.

A condition sensing system for a grain drying system, the condition sensing system comprising:

• a plurality of condition sensing cable assemblies for hanging in a grain storage bin, said assemblies each including a flexible support cable and a data-conveying member extending continuously along the length of said assemblies;
• at least one of said condition sensing cable assemblies having a plurality of humidity sensor assemblies mounted thereon in a spaced apart relationship along the length of the support cable and between first and second ends thereof, said humidity sensor assemblies each including
• an elongate, rigid sensor support member disposed to extend parallel to said support cable,
• a humidity sensor, and
• a protective covering extending around said support cable, said data-conveying member, said sensor support member and said humidity sensor, the support cable and the data-conveying member passing through the protective covering to extend from each end thereof,
• said data-conveying member communicatively coupling to each of said humidity sensor assemblies disposed on the support cable for communicating humidity data from each of said humidity sensors to the grain drying system;
• and
• communication means mounted to each said humidity sensor assembly for communicating said humidity from each said humidity sensor to the grain drying system.