JPH041289B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas purge mechanism for eliminating gases that interfere with measurement from within a spectrophotometer.

When measuring the spectrum of a gas sample using a spectrophotometer, it is necessary to purge the gas in the spectrometer chamber and the sample chamber with a gas that does not have an absorption line in the measurement wavelength range. Generally, in spectroscopic analysis in the infrared region, carbon dioxide and water vapor in the atmosphere have a negative effect on spectrum measurements, so gases such as dry air, nitrogen gas, and rare gases are used to purge the atmosphere inside the spectrometer. . Conventionally, it took about one hour to gas purge the sample chamber and spectrometer chamber, which had the disadvantage that it was not possible to continuously and efficiently measure a large number of samples. That is, as shown in FIG. 1, a light flux passing window 4 is provided in the partition wall 3 between the sample chamber 1 and the spectrometer chamber 2, so that when changing the sample, not only the sample chamber 1 but also the spectrometer chamber 2 This is because the atmosphere enters the spectrometer chamber 2, and it takes a long time to purge the atmosphere in the spectrometer chamber 2. As a countermeasure against this problem, it may be possible to provide a mechanism to shield the light flux passing window 4 when replacing the sample, but this method does not allow light to pass through for adjustment when it is necessary to insert an optical element into the sample chamber. Therefore, it has the disadvantage that optical adjustment is not possible. In addition, in the figure, 7 is a light source chamber.

In view of the above-mentioned problems, the present invention aims to shorten the time required for purging by blocking the flow of gas between the sample chamber 1 and the spectrometer chamber 2 while leaving the light beam passage window 4 open.

The present invention will be explained in detail below based on the drawings. Figure 2 shows an embodiment of the present invention, and 3 in Figure 2a shows an embodiment of the present invention.
1 shows the partition wall 3 between the sample chamber 1 and the spectrometer chamber 2 in FIG. A ring-shaped gas supply pipe 5 is provided along the periphery of the light flux passing window 4 provided through the partition wall 3, and a large number of pores 6 are arranged in a row on the inner surface of the ring of the gas supply pipe 5. . As shown in Fig. 2b, the purge gas ejected from each pore 6 is blown centripetally toward the optical axis of the light flux passing window 4, forming a disk-shaped gas curtain with a large thickness at the center. This prevents air from entering the spectrometer chamber 2 from the sample chamber 1. Further, it is more effective to orient the pore 6 slightly toward the sample chamber 1 as shown in Figure 2a, but since the pressure in the spectrometer chamber 2 is usually higher than the atmospheric pressure, it is not always necessary to It is not necessary to orient the hole 6 toward the sample chamber 1 side.

When using the purge mechanism of the spectrophotometer configured as described above, the sample chamber must be
Before opening the sample chamber 1, supply of purge gas to the gas supply pipe 5 is started, and when the internal pressure becomes slightly higher than atmospheric pressure, the sample chamber 1 is opened to the atmosphere.
At this time, the atmosphere containing carbon dioxide gas and water vapor enters the sample chamber 1, but the spectrometer chamber 2 is closed to the atmosphere by a gas curtain formed by the purge gas ejected from the pores 6 of the gas supply pipe 5. The spectrometer chamber 2 is filled with purge gas at a pressure slightly higher than atmospheric pressure. In this state, after adjusting the optical axis of the sample and the optical elements inserted together with the sample, the door of the sample chamber 1 is closed and purge gas is continued to be supplied to the gas supply pipe 5 for several more minutes. The gas in the sample chamber in an amount corresponding to the amount of gas used is pushed out through the gap in the sample chamber, and the atmosphere in the sample chamber 1 is purged, after which the gas supply is stopped and spectrum measurement is started. In addition, spectrometer room 2
A gas supply means for purging the inside may be provided separately from the ring-shaped gas supply pipe 5, and in that case, the same type of purge gas is used. Furthermore, in an infrared Fourier spectrophotometer that uses a gas bearing for sliding the scanning mirror, the gas used for the gas bearing is also used for the gas curtain.

As described above, the present invention has the advantage that the volume that needs to be purged when changing samples is small, so the time required for purging can be greatly shortened, and measurements can be carried out efficiently.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a conventional example, and FIG. 2 shows an embodiment of the present invention, in which a is a side view of the main part and b is a front view of the main part. 1 is a sample chamber, 2 is a spectrometer chamber, 3 is a partition wall, 4 is a light flux passing window, 5 is a gas supply pipe, 6 is a pore, and 7 is a light source chamber.

Claims (1)

[Claims] 1. A light flux passing window is installed in the partition wall that partitions the sample chamber and the spectrometer room, and a large number of pores are lined up along the periphery of the light flux passing window on opposite sides of the gas supply pipe provided on the spectrometer room side. A spectrophotometer characterized in that the gas pressure in the spectrometer chamber is made slightly higher than atmospheric pressure when a sample is exchanged, and purge gas is ejected from the pores in opposite directions to form an air curtain. gas purge mechanism.