Off-site/on-line/in-situ process to measure the presence of organic substances in fluids or vapors with a photo-ionization detector located within a watertight housing

摘要

An assembly measures the presence of organic substances in fluids or vapors. The assembly has a photo-ionization detector (10) located within a watertight housing through which there is a gas flow. The housing further incorporates an active carbon filter (9) which is protected from saturation overload in different operating modes by a series of magnetic valves (1, 2, 3, 4). A moisture sensor (6) and control module with three or more operating modes are positioned upstream of the pump (5) and a first valve (1). The link between the sample fluid or vapor and the assembly is effected by a membrane (7). During operation the sample flows through the photo-ionization detector, the pump (5) is switched off; valves 1 and 4 are open and valves 2 and 3 are shut. During the assembly gas cleaning phase the pump (5) is switched on, valve 1 is open, valves 2, 3 and 4 are shut. In the self-protection mode, no fluid passes through the photo ionization detector, the pump (5) is off and all valves are shut.