Explosion proof light gate system has the transmitter and receiver in gas tight housings and flushed by inert gas via inlet and outlet connections

摘要

A light gate system for safe use in explosion risk environments has the light transmitter and receiver fitted into one or two gas tight housings with windows. Each housing has gas inlet (26) and outlet (27) connections as well as electrical feed troughs (28, 29). The housing can be a tubular sections sealed by pairs of sealing plates (18, 19, 22, 23) at each end and with integral O ring seals (9) compressed between each pair of plates. The gas flow is designed to flush through the housing covering all parts of the light gate.