Grain loss sensor for pneumatic separation systems of grain-cleaning machines

One of the reasons of poor effectiveness of machines for postharvest grain handling is the difficulty of optimal modes setting under constantly changing input actions. Using of hardware check and technological process control instead of manual adjustment will reduce the costs and improve the quality of postharvest grain handling. A grain loss sensor for device of parameter checkout of technological process of pneumatic systems of grain-cleaning machines is developed. Its operation is based on the analysis of parameters of sound pressure signal, that arises when grains blowing together with impurities are hitting against a wall of settling chamber. The sensor design is developed on the basis of Soho T-1 low-cost piezometric transducer. The sensor is located on the outer side of a wall against which grains are hitting, and lies outside the air stream carrying the impurities and dust. Therefore, the reliability of the sensor increases, and the air stream structure in pneumatic separation system remains steady. The parameters of sound signal arising when grains are hitting against a wall of settling chamber are determined. The researches were conducted with the grains of wheat, rye, oats and barley; the grain moisture content was varied within the range from 12.6 to 35%. The dependencies between the parameters of sound signal arising when grains are hitting against a wall of settling chamber and the grain loss level have been obtained. The operational capability of the sensor was tested on an experimental model of pneumatic separator installed on postharvest grain handling line. The sensor can be adapted for operation in other pneumatic systems of grain-cleaning machines.

grain-cleaning machine, pneumatic separator, control, grain loss sensor, settling chamber, sound pressure level, grain moisture