Patent Number: 041486080
Section: summary

The present invention relates generally to the processing of fluid materials. In its principal application, the invention relates to methods and apparatus for the preparation of samples for radioactive isotope tracer studies and, more particularly, to an improved method and apparatus for preparing such samples by combustion of the starting material containing the isotope tracer. It is a primary object of the present invention to provide an improved method and apparatus for the preparation of samples of radioactive isotope tracer studies, which reduce the sample preparation time far below the preparation times required by the methods and apparatus previously known for the preparation of such samples, with corresponding increases in the sample preparation rate. In this connection, a related object of the invention is to provide such an improved method and apparatus which permit a technician to prepare a much greater number of samples in any given work period, thereby improving the efficiency and reducing the cost of such preparation procedures. Another important object of the present invention is to provide an improved sample preparation method and apparatus of the foregoing type which significantly increase the efficiency of the isotope recovery from the starting material. More particularly, it is a specific object of this invention to provide such a method and apparatus which are capable of recovering essentially 100% of the isotope present in the starting material. A further significant object of this invention is to provide an improved sample preparation method and apparatus of the type described above which virtually eliminate the "memory" of the apparatus so that the amount of isotope tracer in any given sample prepared thereby is substantially independent of any previous preparations carried out in the same apparatus. Thus, a related object of the invention is to provide such an improved method and apparatus which greatly improve the reliability of the resultant samples and the data derived therefrom. Still another object of the invention is to provide such an improved sample preparation method and apparatus which are capable of providing radioactive samples containing little or no oxygen, thereby minimizing the quenching effects caused by oxygen in such samples during analysis thereof. Accordingly, a related object of the invention is to provide such an improved method and apparatus which facilitate analysis of the resulting samples. A specific object of one particular aspect of the invention is to provide an improved combustion chamber for burning liquid or solid samples in an open system so that the combustion products are continuously removed from the combustion chamber, and including means for facilitating thorough cleaning of the chamber in a rapid and efficient manner after each combustion. Thus, a related object of this aspect of the invention is to provide such an improved combustion chamber which has virtually no memory, even when used to burn radioactive samples. In another aspect of the invention, it is an object to provide an improved heat exchanger for condensable vapors which provides an extremely high heat transfer with only a small volume and surface area and in a very short time period. In this connection, it is also an object of this aspect of the invention to provide such an improved heat exchanger which is capable of receiving the products of combustion of a radioactive sample and continuously condensing the vapors therefrom in a rapid and efficient manner. Yet another object of a further particular aspect of the invention is to provide an improved gas-liquid reaction column which achieves a high reaction rate between the gas and liquid, and yet can be thoroughly cleaned in a matter of seconds between successive batch-type reactions so that the column has virtually no memory, even when used to react radioactive materials. Another important object of the present invention is to provide an improved radioactive sample preparation apparatus which achieves all the objectives mentioned above at a low cost and with the use of highly reliable components, and which is easy to operate.