Cryogenic automation

Liquid nitrogen is colorless, odorless and non-toxic, which is precisely why its hazard goes unnoticed. In a closed tank room a small leak displaces oxygen without warning. In the same room, decades of samples sit at −196 °C, and if the level is not watched over a weekend those samples are lost too. Cryogenic infrastructure has to answer both risks at once.

Personnel safety

• Fixed oxygen deficiency detection in storage and filling areas, with the alarm visible before entering the room
• Interlock between the oxygen alarm, filling and ventilation: on alarm, filling stops and exhaust starts
• Sensor placement at breathing level near the tank, with periodic calibration

Sample safety

• Level measurement by four-point sensor or hydrostatic differential pressure, with fill start and stop thresholds
• Temperature probe placed at the warmest point, typically the upper rack level
• Alarms for low and high level, high temperature, fill timeout, sensor fault and power loss
• Battery backup so alarms continue during a power failure

Central tank, filling station and piping

Instead of carrying individual dewars, a bulk tank outside the building feeds a filling station through vacuum-jacketed piping. This regulates pressure, automates filling, removes spill and tipping risk during transport, reduces evaporative loss and limits personnel exposure. A PLC combines bulk tank pressure, line cool-down, phase separation, per-tank level and temperature signals and the oxygen detector contact into one control logic.

Monitoring integration

Controller data — level, temperature and fill events — is delivered over Modbus or MQTT into GE-MON, so cryogenic infrastructure appears on the same dashboard and in the same audit reports as the rest of the equipment.