Patent ID: 6722214
Filing Date: 2004-04-20
Classification: B04B

Abstract:
A method of evaporating a liquid sample contained in a sample holder which is mounted within a chamber and rotated by a rotor at speeds which are monitored to produce speed signals therein during the evaporation so that a centrifugal force is exerted on the contents of the sample holder during the process whilst a pressure below atmospheric is maintained in the chamber in manner known per se, so as to leave as a residue any solid material dissolved or otherwise mixed in the liquid forming the sample, comprising the steps of:mounting a transducer to monitor the centrifugal force acting on the sample holder relative to the rotor when rotating at a given speed and obtaining a force signal therefrom, supplying the force signal to a computing means, programming the computing means to compute a value equivalent to the centrifugal force exerted on the sample holder due to rotation of the rotor at said given speed, further programming the computing means to computer a weight of the liquid sample and sample holder from the force signal using the computer centrifugal force, and further programming the computing means to generate a control signal for controlling the evaporation process in dependence on the computed weight, wherein the computing means includes a microprocessor adapted to rotate with the rotor.