MULTISHIFT GRAVIMETRIC DUST SAMPLING INSTRUMENT

A respirable dust sampling instrument, which can collect dust over a number of working shifts to a pre-programmed pattern, is described. The instrument can operate unattended underground with placing and retrieval being carried out at convenient times.The new instrument is similar in general construction to the MRE (Type 113A) instrument, selecting respirable dust with the aid of a horizontal elutriator, but at a lower flow rate of 0.625 l./min. Dust from all the shifts sampled is collected on a single filter circle. The instrument incorporates a mechanically driven programming clock, with sampling shift segments on a 24 h dial. A 'shift selector' mechanism allows for such requirements as stopping sampling over the weekend and various patterns of shifts on different days.The Multishift Sampler gives results in good agreement with those from the MRE sampler and extended operational trials have indicated that it could with advantage be used as a replacement for the latter instrument. © 1979, British Occupational Hygiene Society.