Using a Conveyor-Mounted Spout Sampler to Obtain Farmer Stock Grade Samples

Authors: Butts, Christopher - Chris; Lamb, Marshall; Sheppard, Harry - Hank; Kandala, Chari

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2009
Publication Date: 5/9/2009
Citation: Butts, C.L., Lamb, M.C., Sheppard, H.T., Kandala, C. 2009. Using a Conveyor-Mounted Spout Sampler to Obtain Farmer Stock Grade Samples. Applied Engineering in Agriculture. 25(3):385-390. 2009.

Interpretive Summary: The value of in-shell farmer stock peanuts must be determined several times throughout the marketing chain. This requires obtaining a sample that adequately represents all the components of the load of peanuts such as foreign material, loose shelled kernels and in-shell peanuts. When peanuts are first sold by the farmer, this sample is obtained using a pneumatic or vacuum type sampler to extract the sample from the load of peanuts. A device mounted in a downspout of a bucket elevator to periodically pass through a flowing stream of peanuts has been approved for many years to collect samples for value determination. However, peanuts are transferred by conveyor belt many times during post harvest processing. A spout sampler was adapted to mount on the conveyor belt discharge to obtain a representative sample while transferring peanuts. Tests were conducted on peanuts unloaded from a bulk storage facility into a semi-trailer that compared the peanut value based on samples obtained using the conveyor in-stream sampler and the more commonly used pneumatic sampler. The peanut value estimated from both samplers was the same. Therefore, this type of sampler may be used any time peanuts are transferred using a belt conveyor. This will allow a facility to eliminate the need for a separate process of extracting the sample using the pneumatic sampler. These tests also made it possible to determine the best operating parameters such as the width of the sampling slot and how often the sample passes through the flowing stream of peanuts.

Technical Abstract: Accurate determination of the value of load of peanuts is contingent upon obtaining a representative sample. Devices have been approved to extract a representative sample from a static load and from peanuts as they flow through an elevator downspout. A device that rotates a diverter through the flowing stream of peanuts to divert a small sample of peanuts for grading was mounted on the discharge of a belt conveyor. Tests were conducted in which the slot width was varied from 32 to 95 mm and sampling interval ranged from 20 to 120 s. The total mass of peanuts collected in a sample was recorded. After filling the trailer, a sample was retrieved using the conventional pneumatic sampler. Both grade samples were evaluated and quality parameters were compared. The percent foreign material and loose shelled kernels were lower in the spout samples (3.5 and 2.5%) compared to that observed in the pneumatic samples (4.2 and 3.3%). Foreign material also tended to decrease in the spout sample as the slot width increased. There were no significant differences in percent total sound mature kernels, other kernels, and hulls, thus making the peanut value the same regardless of sampling method. As expected, the amount of peanuts collected per swath increased as width of the slot increased, but was not affected by the sampling interval. Equations were developed to estimate the total sample size if the sampling interval, slot width, and total amount of peanuts passing through the sampler.