Design and testing of a prototype in-line chip quality monitor

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Virginia Tech


This project involved the design and testing of a prototype in-line chip quality monitor for gathering process control information for the manufacturers of wood chips.

This monitor specifically addresses three common complaints with current chip sampling procedures. Chip sampling occurs too late in the process. It is inadequate. It is too infrequent to develop management information.

The monitor is composed of a double screen drum separator to divide chips into oversize, accepts, and pins/fines. Counterbalanced tip buckets are used to weigh each size class. Tip bucket cycles are recorded by a computer via magnetic proximity switches attached to each bucket. This information is then used to chart production of chip size classes, updated continuously over the sorting period. This monitor is capable of sorting one ton of chips per hour.

Two trials were conducted to test the monitor. One in a lab environment, and one on site at a chip mill. Both trials compared monitor output with independent samples classified using a Williams classifier. The trials showed that outputs were consistent with Williams output.

This monitor can effectively chart chip distribution information. This process control information provides the manufacturer with immediate knowledge of chipper performance.



control chart, classifier, monitor, chip classification