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Floyd County, Iowa | jmiller - 7/10/2017 21:36
Way back 35 years ago I held a state grain graders license. Was told at grain grading school to not re-test the same sample. Said to use Boerner divider as many times as necessary to reduce the sample to the amount needed to test. If you want to re-test sample, run untested grain back through divider as many times as necessary to reduce sample and test that sample. He showed us the result of re-testing the same sample over and over. I don't remember if sample moisture increased or decreased. He showed us the same results using several brands of bench type testers. Had a large Dickey John tester, a farm duty Dole and Radson, a Steinlite, and a couple others. Showed us how inaccurate the hand-held testers of the day could be. Hand-held testers needed to have a good representative sample and multiple samples tested and averaged. Grain testers of the day measured moisture by capacitance. I'm sure technology has changed a lot since then, but then again, maybe same principles apply. I haven't seen a big old copper Boerner divider used in years.
Yes, but that's for actual load sampling. You have to have a "representative sample" for the whole load, so I too, was taught to take 2 samples from trucks, or a large enough sample from a single wagon, mix them by hand, then run it through the divider to reduce to a decent size sample.
BUT, we're talking about calibrating a sampler, not grading a load.
The unit has to test a control sample, then calibrate if necessary, then run the SAME sample back through, etc, until it is within reason. You don't want to try and calibrate a tester using several different samples (like from a truck load coming in from the field), as they very well COULD be off a point or more from each other, but the same control sample should be within 1 to 3 tenths of a percent.
The whole point of calibrating is to try and adjust to as close to the actual control sample moisture as possible.
Incidentally, only farmers' hand samplers could be calibrated, and they had to do the adjustment themselves.
The commercial testers have to be calibrated at a licensed repair station, then certified and sealed.
If they are tampered with at the elevator, that elevator is at risk of losing their grain dealers license. The state inspectors only check to ascertain that the tester is within parameters.
Last I knew, acceptable (to state USDA) was within 1/2 point of the control sample. Meaning the state could have 15.0%, we could have 14.5%, and the competitor across town could have 15.5%, so they were all within acceptable parameters.
You undoubtedly already know that, but many here don't.
And yes. things have changed with the testers. The way it was explained to me is that the oldest testers were similar to a doctor's physical exam. The next generation of testers was similar to x-ray. The latest are like MRI. | |
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