Real-time control of exhaust flow

Abstract

An interferometric detector detects fluctuations in fluid properties in the vicinity of an exhaust hood to control protective skirts that reduce the exhaust air requirement.

1 . A detector for detecting fumes escaping from an exhaust hood, comprising: 
 an optical interferometer configured to send light through a sample path and create an interference pattern with respect to a reference beam in the vicinity of an exhaust hood;    an optical detector configured to detect fluctuations in said pattern;    a controller configured to detect said fluctuations and respond to a pattern thereof by generating a control signal for controlling a mechanism for controlling a shield that at least partly covers an access of said exhaust hood.