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Helium recovery system

The helium evaporating from the He-cooled experiments is recovered in a semi-closed cycle. The helium is first channeled into the central recompression plant where it is compressed and stored. In the following the helium is transferred to the Walther Meißner Institute (WMI) via a high pressure line where it is reliquified.

Prerequisites for an efficient recovery cycle are an air contamination level <0.4%, a water contamination level<0.04% and an overall gas loss <5%. In order to meet these requirements, the recovered gas is continously monitored by different gas meters and sensors.

In particular, the careful participation of all LHe users is necessary in order to meet the demands an gas purity and gas losses. To this end, all users can access the current measurement data of the He recovery plant here, and can thus participate in the monitoring process. Notably, users can temporally correlate changes to their own lab LHe-facility with changes of gas purity and gas flow. Note that there is a finite time lag due to the recovery line length between your experiment and the recompression plant.

The air contamination in the recovery lines from Physik 1, Physik 2/WSI/ZNN and Chemie is monitored by O2 sensors.

  • GasPurity shows the evolution of the air contamination during the present day in order to enable the users to identify and eliminate leaks and contaminations associated with their own experiment.
  • GasInflow shows the time evolution of the gas meter readings of Physik 1, Physik 2/WSI/ZNN and Chemie.This yields information concerning the current capacity utilisation of the recompression plant. Overloads is given for a prolonged gas inflow rate > 50 m3/h.
  • GasOutflow shows the filling level of the storage balloons and the operating condition of the compressors.
  • Pressures shows the absolute pressure of the low-pressure lines coming from the laboratories and the pressure of the two high-pressure storages.
  • Temperatures shows the temperatures of the gas meters in the recompression plant and of the high-pressure storages. Temperature and pressure are needed for the evaluation of the absolute gas amount. The dew point temperature is a measure for the water content of the helium. A high water content can lead to condensation in the high-pressure lines.

Current values shows a summary of the current values of the measured quantities. In addition, malfunctions are indicated here.

The recovery plant is shown schematically in RecoveryPlantSchematics.

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