Investigation of effect of geometry on performance of grit collection troughs

An investigation has been made to determine the effect of geometry on the performance of six collection troughs that served to collect and store grit captured by a model grit chamber. The grit employed was a 0.1mm sand fraction obtained by sieving and the width of the channel of the model grit chamber was 0.5 ft. Over a hundred experiments were performed which spanned a range of velocities of from 0.31 to 1.1 ft/sec and a range of depths of from 0.1 to 0.36 ft. The performance of the grit chamber - collection trough units was evaluated in terms of percentage grit capture under comparable flow conditions and observation of grit travel patterns.

The results indicated that the performance of the troughs was influenced by the volume, the depth to length ratio and the slope of the upstream and downstream walls. High performance appeared to be induced by large volumes, moderate depth to length ratio, vertical upstream wall slope, and a downstream slope of 2 vertical to 1 horizontal.