JPS6323498B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a graphite tube for a flameless nuclear reactor used for atomic absorption spectrometry.

Flameless atomization reactors run a large current through a tube made of graphite to generate heat to a temperature of nearly 3000℃, and use this thermal energy to atomize the sample. Because the structure was such that the sample was dropped directly into the graphite tube that formed the furnace, not only was the furnace body susceptible to damage due to chemical and physical effects, but the sample also spread inside the furnace and was difficult to detect. There was a problem that the sensitivity decreased. In order to solve these problems, some proposals have been made in which a sample cell is inserted into the furnace body to prevent the furnace body from coming into direct contact with the sample and to prevent the diffusion of the sample. Since the sample cell is placed on the cylindrical inner surface of the reactor body, the contact state between the sample cell and the reactor body is unstable, and the degree of thermal equilibrium between the two is inconsistent, resulting in variations in the degree of atomization, that is, the detection sensitivity. It was hot.

In view of these problems, the present invention supports the sample cell from both sides by forming a box-shaped sample cell placement part in the lower part of the furnace body, allowing the sample cell to be stably placed. It is an object of the present invention to provide a graphite tube in which the degree of atomization of a sample is stabilized by improving the degree of thermal equilibrium between the cell and the cell.

Therefore, details of the present invention will be explained below based on illustrated embodiments.

FIG. 1 is a block diagram of an apparatus showing an embodiment of the present invention, in which reference numeral 1 is a graphite tube which is a characteristic part of the present invention, and a cylindrical part 2 for atomizing a vaporized sample is shown. A groove-shaped box part 3 is integrally formed in the lower part, and the whole is made of graphite material to form a cylindrical body with a bottomed horseshoe-shaped cross section, and the cylindrical part 2 and the box part 3 touch and protrude to the inner surface. The ridgeline portions A and A are formed as a mounting portion for the sample cell S. In the figure, reference numeral 4 indicates a sample injection hole formed at the center of the top, and 5 indicates an inert gas outlet hole.

In this embodiment, when the sample cell S is inserted into the box part 3 below the sample injection hole 4, the box part 3 supports the sample cell S from both sides by its two ridgelines A, A, and holds it inside the tube 1. be held in a stable and constant state. When the tube 1 is energized in this state, the current flows through the tube 1 with low electrical resistance without passing through the sample cell S that is in line contact with the tube 1, causing the tube to generate heat and causing the defect inside the tube 1 to flow. The sample cell S is uniformly heated via active gas. When a sample is dropped from the injection hole 4 at this point, the sample is atomized at a constant rate in the cell S, which is heated uniformly at a high temperature, and this atomized sample is guarded by the wall of the cell S and diffused. The atomic atmosphere rises without any movement and forms a highly concentrated atomic atmosphere in the cylindrical portion 2, and is detected with high sensitivity by a spectroscopic analyzer (not shown).

As explained above, according to the present invention, the box-shaped sample cell mounting part is formed at the bottom of the graphite tube, so that the furnace body and the sample cell are always in constant contact with each other to maintain a stable thermal equilibrium state. can be formed and the degree of atomization can be kept constant. Furthermore, by making line contact between the furnace body and the sample cell, not only can wear of both be reduced, but also the durability of the sample cell can be improved since no electrochemical action occurs on the sample cell. Can be done.

[Brief explanation of the drawing]

FIG. 1 is an external view showing one embodiment of the present invention, and FIG. 2 is a sectional view of the same device. 1...Graphite tube, 2...Cylinder part, 3...Box part, 4...Sample injection hole, S
...sample cell.

Claims (1)

[Claims] 1. In a graphite tube for a nuclear reactor that generates heat by Joule heat by applying a voltage to both ends, the cross-sectional shape of the tube is shaped like a horseshoe with a bottom, and a box-shaped sample cell mounting portion is integrally extended below the cylindrical portion. A graphite tube for a flameless nuclear reactor characterized by the following: