Chromtech - Model H2 - Hydrogen Sensor
From Gas Chromatography
Self contained solid state unit for the continuous monitoring of air in a gas chromatographic oven. Sensitive to hydrogen if leaking occurs in the carrier gas system. The use of hydrogen as a carrier gas in capillary column gaschromatographs has a lot of advantages. The only indication against the use of hydrogen as a carrier gas is the possibility of an explosion in the oven compartment in case of leakage. The permanent monitoring of the air in the oven of the GC with the H²-Sensor-, eliminates this danger completely.
Principle of operation
Continuously circulated air in the GC oven flows through the thermostabilized sensor head, causing a signal change by hydrogen detection. The measured gas concentration will be displayed on the front panel and on the indicator band. Gas concentrations that exceed the set threshold will trigger the acoustic signal and optical alarm. The acoustic signal can be switched off at the rear of the electronic panel with the sound switch.
Description of the system
The H² -Sensor consists of a gas detector head and electronic control unit. The gas sensor head is mounted at the rear of the GC and the 1/4' pipe leading into the oven compartment and is connected to the monitor unit (Sub D, 9 pol). The electronics is protected by the 2 piece thermoplastic housing. The front panel view shows operational conditions.
Should the hydrogen alarm be triggered, the relay output GA 1 will switch the safety valve unit (P/N 9 1000801) to an inert gas (N2) to prevent damage. (e.g. explosion; save column). Factory pre-set at 1% by vol. H² in air.
The relay output GA 2 will simultaneously send the GC into forced cooling, switching off the oven heating power. All relays are set in alarm position if power fails or is switched off.
The front panel will show the hydrogen concentration and the LED digit display in a percentage of the full scale and at the same time on the LED indicator bar. If the H2 concentration is above set threshold level, the alarm will be released; the LED display and indicator bar light intermittently; 'Alarm-/Reset' lights up and an audible alarm sounds.
When the concentration level falls 20% under the set limit of 1% H² by volume the 'Alarm/Reset' lights intermittently; the LED display and indicator bar light will be normal again.