ICAR-CIAE Grain handling cum in-situ surface disinfestation treatment system

Background

The food grains are generally harvested at higher moisture content to minimize the shattering losses. The harvested grains needs to be dry up to their recommended safe level of moisture content for storage. The drying of the food grains up to desired moisture content is also vital in mills and other grain processing units. The open sun drying at yard is the common practice mostly followed at farms, mandies, processing facilities and mills. Various operations like spreading, layering, collection, bagging etc. taking place at the yard are highly laborious, time taking and cumbersome. The practice some time fetch the huge loss due to sudden unprecedented rains, cross contamination etc.

Further, the application of appropriate disinfestation aid is mandatory requirement for the long-term safe storage of food grains. The conventional ALP based chemical fumigation causes serious issues of creation of resistance among the major insect species, residual of poisonous chemical etc. The various non-chemical disinfestation methods have been tries at the laboratory level shown prominent effect on the disinfestation of food grains. The appropriate deployment of such techniques in operator’s friendly mechanical system suitable for Indian conditions have remain a challenging task. Among the various physical disinfestation methods Infrared (IR) shown the promising effect of insect mortality as well as early stage disinfestation of the food grain with non-significant effect of quality attributes of the grains. The use of IR heating is proven a cost-effective way for any type of surface treatment.

Hence, the integrated system which perform all the operations at grain drying yards like grain collection, conveying, bagging and replace the traditional laborious, time consuming system with mechanical system was a great demand. Also, integration of appropriate physical (IR based) in-situ grain surface disinfestation approach have potential for significant reduction in losses during handling and post-harvest value chain of the good grains.

Technology Details

The mechanized self-propelled grain handling (collection, conveying and surface treatment) cum bagging system was developed to address the issues in conventional practice. The developed mechanized system consists of two opposite direction-rotated screw conveyors fitted at front rotated at the speed of 250 rpm for gathering the spread grains at center, the specially designed inclined bucket elevator pick the grain from floor and conveyed it up to overhead hopper. The hopper of the machine with surge capacity of 10 kg of grains metered and discharges grains from its bottom to the reciprocating conveying deck keeping in view of single layer mentioned on deck. The conveying deck contains about 4.5 kg of grains (wheat) at a time and conveyed towards discharge chute through its reciprocating movements. The conveying deck also equipped with overhead array of 05 nos. of infrared heaters (1000 W each) provided to give in-situ surface heat treatment (standardized and optimized under separate experimentation for different insect species and type of grains) for early stage disinfestation of the conveying grains. The infrared treatment time of 45-60 s can be maintained as per the requirement for targeted insect species, life stage and type of grain through adjusting the reciprocating movement of deck.  The grains were further collected in the attached bag at the discharge end of the deck. The grains were further collected in the attached bag at the discharge end of the deck. At the same time, a specially designed DC motor-driven cleaning brush mechanism, positioned just behind the grain collection screws, gathers the remaining grains to one side and cleans the floor. The whole system is running by 3 Hp electric motor. The machine has a capacity of 0.6 tonne/h bagging of free flowing grains. The machine is self-propelled and operated with forward speed of 0.7 km/h. The machine has been tested with wheat and chick pea grains. At the optimized operating conditions, the machine fetch about 93% of grain collection efficiency with <5% of broken. Infrared surface treatment achieves 100% insect mortality, 98% of germination with non-significant effect on various selected quality attributes of food grains (wheat and chickpea). The storage life of IR treated wheat and chick pea grains was found to be increased up to 1 year without any fumigation.