The concept of grain drying is relatively simple with different types of systems incorporating:-
- A large fan and burner which forces heated air into a void beneath a vented floor of an area into which up to 20,000 bushels of grain have been stored. The hot air flows through the vents and up through the grain. Vertical augers may continuously mix the grain in an attempt to ensure uniform drying.
- Continuous flow systems (Horizontal or Vertical) - whereby wet grain is exposed to heated air which is forced into a plenum area and equally distributed through individual columns of metal mesh walls.
In all grain drying systems regular and detailed maintenance is essential to aid continuous uninterrupted operation of the dryer.
There are many potential alarm conditions that can be generated during the use of a grain dryer:
- Very fine particles of grain may build up close to the open flame burner and cause reduced air flow or improper sensor operation
- Where a malfunction of temperature control equipment allows a burner to continue operation after the grain is dry, elevated temperatures capable of igniting the grain can occur
- Mechanical failure of fan bearings, auger bearings or gearboxes can cause frictional heating capable of igniting the grain
- Collapse of the grain bin floor allows grain to be in close proximity to the burner plenum
- When conditions dictate that extremely high moisture grain be harvested, the grain can sometimes be damaged during the process. The damaged grain has more fine particles than that harvested at times of lower moisture content
- Worn or improperly adjusted harvesting equipment can cause excessive damage to the grain
- In all types of grain dryers the possibility of over-heating at electrical connections can be an additional source of ignition