公开(公告)号：US20190195768A1

公开(公告)日：2019-06-27

申请号：US16322370

申请日：2017-07-28

Applicant: PCME Limited

Inventor： David Christopher Unitt ,  Trevor Allan Lye ,  Bruce Greetham

IPC: G01N15/10 ,  G01F1/74 ,  G08B17/107

CPC classification number: G01N15/10 ,  G01F1/74 ,  G01N15/0205 ,  G01N21/15 ,  G01N21/53 ,  G01N2015/0096 ,  G01N2015/1075 ,  G01N2021/536 ,  G01N2201/024 ,  G01N2201/12707 ,  G08B17/107

Abstract: A method and apparatus (1) for monitoring particles flowing in a stack are disclosed. The method comprises emitting light from a light source along an optical path for scattering from the particles, rotating a rotatable monitoring assembly (15) mounted in the optical path, and detecting the scattered light using a detector. The rotatable monitoring assembly (15) contains at least two in apertures, and the method further comprises rotating the rotatable monitoring assembly (15) into a plurality of different configurations. In an operation configuration, light passes through the rotatable monitoring assembly (15) and into the stack unimpeded. In a zero-check configuration, the rotatable monitoring assembly (15) blocks the light from reaching the stack. In a span-check configuration, light of varying intensity passes from the light source through the rotatable monitoring assembly (15) into the stack. In a contamination-check configuration, the light is reflected through the rotatable monitoring assembly (15) onto the detector, without entering the stack. In the safety-shutter configuration, the rotatable monitoring assembly (15) protects optical components in the instrument from particles in the stack.