The model GA33 multiplexer is connected upstream of an emission monitor e.g. model GA35 or GA38. Emission monitoring of SF6 gas is required in closed rooms with SF6 gas-filled equipment. For example, this could be a switchgear or a gas depot.
Most of these places are physically separated or too large for a central measuring point. With the help of the multiplexer, up to 10 measuring points can be monitored with one emission monitor. Thus the instrument scans through all active sampling boxes at a predefined interval. If a measuring point is not needed, it can be completely switched off within the instrument configuration.
Since SF6 gas sinks to the bottom due to its high molecular weight in comparison to the ambient air, it makes sense to place the sampling boxes close to the ground. To protect the infrared measuring chamber, one filter is fitted on the multiplexer for each measuring point.