Method of Expanding Measurement Limits of Digital Dynamometer in Testing Strength of Moulded Peat Products

The work is carried out to survey operating quality of sod peat produced by milling-forming machines in the field. The surveillance will help make necessary changes in mining machine designs and operating modes in a timely manner. One of the most important quality parameters of sod peat is its bending strength. To evaluate it, Tver State Technical University has developed a destruction test bench. The test bench is equipped with a digital dynamometer and a strain-gauge bracket torecord the destructive load. However, the instruments are designed for 1 kN maximum load. The bending tests of moulded peat products conducted by the authors showed that the destructive load often exceeds 1 kN, which meant that the generation and measurement limits of destructive load have to be expanded within the range of equipment being available. The problem has been solved by installing additional elements in the strain- gauge bracket and making a calibration chart. The method can expand the generation and measurement limits of destructive load by more than 50 %.