Rapid Quench Cold-seal Hydrothermal Apparatus with Computer Controlled Pressure Cycling and Temperature.

-Suitable for hydrothermal experimentation at pressures up to 2kbar and temperatures up to 800°C.

-The reactor vessel is in two main parts, with the cold seal and cooling jacket between them. The bottom part is 316 stainless steel and the top heated part is Rene 41 high temperature alloy. They are separated by a cold (room T) seal (Be-Cu alloy), which is surrounded by a cooling jacket fed by room temperature water. Thus the bottom part and cold seal are at room T and experimental P, and the tip of reactor vessel at the top is at the experimental T and P. Water is the pressure medium, and its reservoir is separate from the cooling water system.

-The sample is contained in an Au capsule at the top of a sliding assembly which can move up and down with a magnet external to the reactor assembly, for rapid quenching of the experiment.

-Pressure control: National Instruments LabView controls a stepper motor and gear reduction unit which drive a high pressure generator. Pressure is controlled via feedback from a high pressure transducer and an optical encoder on the motor. Pressure is monitored by the user via an on screen digital display from the transducer, and an analog (Heise) gauge.

Pressure can be ramped, specified in a text file with increasing time and attendant pressure, paired and arranged in columns. LabView ramps the pressure as expressed there, and where dP/dt is constant between each pair. Experiments can be depressurized instantaneously by opening a valve.

-Temperature control: LabView controls current to a tube furnace surrounding the pressure vessel. Temperature is controlled by feedback from one of two thermocouples at the user's discretion. One is in the furnace, the other is attached to the pressure vessel. Temperature is monitored by the user via on screen digital display. Samples can be quenched instantaneously by lowering the capsule from the tip of the hot bomb to below the cooling jacket.