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pressurized nitrogen tank with liquid nitrogen (≥ 0.5 bar pressure)
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flushed nitrogen lines in the heat exchanger (30 mins, 250 mg/s nitrogen gas flow)
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Attach solenoid valve (blue rectangle) to the nitrogen tank using the orange labelled screw.
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Keep the yellow manual valve closed! (yellow arrow)
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Switch on electricity on the extension cord and wait until the system beeps (ca. 10 sec).
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Reset solenoid valve with “VALVE – TEST” button and wait until it beeps (ca. 10 sec)
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Open yellow manual valve on the pressurized tank.
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Place heat exchanger carefully in the nitrogen dewar.
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Try not to touch the temperature sensors on the rod or the nitrogen inlet.
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If you need to adjust the heat exchanger in the dewar, please move it ONLY along the yellow marked axis. Avoid touching the sensors (red) or the nitrogen inlet (blue).
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After 30 mins, reduce nitrogen gas flow to 200 mg/s on the Hydra.
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The time and temperature thresholds are stored, but before your session, please check, if the values are correct:
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TIME = 7 mins, MIN-sensor threshold = -190°C, MAX-sensor threshold= -192°C
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The solenoid valve closes if either the MAX-sensor's temperature threshold is reached (-192°C) or if the timer runs out (7 mins). At lower nitrogen tank over-pressure (< 70kPa), you may increase the timer to 12 mins by turning the blue arrow clockwise to 12.
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Close yellow manual valve on the pressurized nitrogen tank.
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Switch off the electricity.
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Carefully remove heat exchanger from the nitrogen dewar.
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Close dewar with the cap.
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Increase nitrogen gas flow to 250 mg/s on the Hydra for 60 mins, to flush the nitrogen lines and avoid ice build-up.
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Reduce gas flow to 20 mg/s on the Hydra until further use.
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Close the yellow manual valve on the tank.
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Unscrew only the closest nut to the yellow manual valve.
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Please DO NOT screw the other nuts to avoid damaging the solenoid valve
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Gently place the solenoid valve on the floor.
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Release pressure from the tank, refill nitrogen. Pressure build-up to 0.7 bar takes ca. 4 hours, when the tank is full.
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Please consider, that pressure build-up takes ca. 4 hours, thus it is recommended to fill the tank in the morning.
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Before exchanging and refilling the pressurized nitrogen tank, it is recommended to completely fill the nitrogen dewar. A full dewar lasts ca. 20 hours.
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On the MIN temperature control unit, press the down arrow once. The threshold value starts to blink.
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Using the arrows, adjust the temperature threshold value to e.g. -196°C.
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Confirm temperature threshold change with the OK button.
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The new threshold should be below the current temperature. E.g. -194.5°C > -196°C. This will trigger the solenoid valve to open.
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After the nitrogen dewar is filled, reset the MIN temperature threshold back to -190°C!!!
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