A CRYOGENIC SCIENTIFIC REFRIGERATION SYSTEM WITH VARIOUS POTENTIAL APPLICATIONS, BUT TYPICALLY USED WITH X-RAY DIFFRACTION APPARATUS FOR THE INVESTIGATION OF MATERIALS/MOLECULAR STRUCTURE. THE SYSTEM CONTAINS NO X-RAY COMPONENTS. A GAS PUMP PROVIDES GAS FLOW FROM AN UNPRESSURISED DEWAR, THROUGH A FLEXIBLE VACUUM INSULATED TRANSFER LINE INTO THE COLDHEAD. ONCE INSIDE THE COLDHEAD, THE LIQUID NITROGEN PASSES THROUGH A HEATER, WHICH EVAPORATES MOST OF THE LIQUID INTO GAS. THE GAS THEN FLOWS OUTWARD ALONG ONE PATH OF THE HEAT EXCHANGER, THROUGH THE TEMPERATURE CONTROLLER, TO ARRIVE AT THE PUMP APPROX 10 KELVIN BELOW ROOM TEMPERATURE. THE GAS THEN FLOWS BACK INTO THE COLDHEAD WHERE IT IS RE-COOLED ALONG THE SECOND PATH OF THE HEAT EXCHANGER. THE GAS TEMPERATURE IS REGULATED BY A HEATER AND A SENSOR BEFORE ENTERING THE ISOTHERMAL NOZZLE AND OUT OVER THE SAMPLE.

CLASSIFICATION HAS BEEN DETERMINED IN ACCORDANCE WITH THE FOLLOWING:- GENERAL INTERPRETATIVE RULES (GIR)S GIR 1 HAS BEEN USED TO CLASSIFY THIS PRODUCT BY THE TERMS OF HEADING 8418 REFRIGERATORS, FREEZERS AND OTHER REFRIGERATING OR FREEZING EQUIPMENT, ELECTRIC OR OTHER; HEAT PUMPS OTHER THAN AIR CONDITIONING MACHINES OF HEADING NO. 84.15. GIR 6 HAS BEEN USED TO CLASSIFY THE GOODS TO SUBHEADING LEVEL. 841869 OTHER REFRIGERATING OR FREEZING EQUIPMENT; HEAT PUMPS; OTHER THAN HEAT PUMPS OTHER THAN AIR CONDITIONING MACHINES OF HEADING 8415. TARIC CODE 8418690090 OTHER THAN FOR USE IN CIVIL AIRCRAFT. ALSO CLASSIFIED IN ACCORDANCE WITH:- HSEN NOTE (I) TO HEADING 8418