Guest Article
Richard C. Suiter Richard Suiter Consulting Hopper Scale Field Test
The testing of hopper scales seems to intimidate many field inspectors. They dread the task of doing a substitution test or a strain load test; there is often confusion about the difference between the two types of tests, how the error is determined at the various test points, and how the tolerances are to be applied. I intend to explain those tests in a manner that will alleviate some of those apprehensions. While there are obstacles to be overcome, such as having the appropriate amount of known test weight readily available and having an easy method for applying that test load, the mechanics of the actual test procedure are, in reality, not much more difficult than a properly executed test of a large vehicle scale.The key is in having the right equipment for the test, understanding the tests to be performed, and understanding how to interpret the results of the tests. I’ll start with a list of equipment that may be necessary for the average hopper scale test. Then I will explain a few terms and types of tests that, while not unique to hopper scales, are more frequently associated with that type of inspection. Finally, I will outline the tests to be performed, including the application of weights, the calculation of the tolerances, and the determination of errors. For the purpose of this discussion I am going to assume that we are testing a scale we have not tested--nor even seen--previous to the request for inspection. Equipment. In order to know what equipment is necessary to conduct a proper test, you need to know something about the scale in advance of the test. An on-site visit prior to the scheduled test date is the best way to determine the necessary equipment for an appropriate test. Sometimes an on-site visit is not practical or even possible.
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