Bruker BioSpin NMR BVT3200, Technical Manual

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Technical Manual Version 002 BRUKER BIOSPIN 17 (55)
2
Options 2
Low temperature options 2.1
For sample temperature control below room temperature one must use cold gas.
The BVT3200 can drive several devices for cold gas production :
•
LN
2
heat exchanger
•
LN
2
evaporator
•
BCU05 gas cooler
The nitrogen level in the dewar is monitored by the VTU and the power level
applied to the LN
2
heater is computer controlled. For both first options, an optional
printed circuit must be installed. The LN
2
heater cable or the exchanger cable is
plugged in the N
2
connector on the front plate.
LN
2
exchanger 2.2
This device allows to extend sample temperature control below room
temperature. A nitrogen gas supply line is required for this device. The N
2
gas is
cooled while passing in a heat exchanger tube which soaks in liquid nitrogen. The
cold gas is then transferred to the probe by a flexible isolated transfer line.
The gas flow is stopped (it means all four valves are closed in the BVT3200)
whenever the heater power is off, avoiding sample freezing.
A printed circuit (PC) must be installed in the VT unit.
The printed circuit has the part number W1101455. It is plugged on the main
printed circuit and fixed by four plastic spacers.
Temperature accuracy is unchanged.