| 摘要 |
A device for withdrawal of a fixed volume of powdered, liquid or gaseous material from a withdrawal zone and for conditioning the withdrawn materials for the purpose of analysis which comprises a retractable cylindrical probe in which there is provided a cavity of known capacity, a retractable sleeve coaxially disposed over the probe for permitting or preventing access to the cavity, a substantially closed chamber in which the probe and sleeve are disposed for reciprocal movement into and out of the withdrawal zone, whereby the probe and sleeve may be extended from the chamber into the withdrawal zone, the sleeve may be retracted to fill the cavity, the sleeve may be extended to seal the cavity, the probe and sleeve may be retracted from the withdrawal zone back into the closed chamber, and finally, the sleeve may again be retracted to permit conditioning of the withdrawn material. |
