JP3138552U - Flame photometric detector - Google Patents

Abstract

To provide an FPD with little change in the hydrogen flame formation position even when the flow rate of fuel gas or auxiliary combustion gas is changed, and to enable analysis by FPD while always maintaining a good S / N ratio.
Deflection means for deflecting the flow of auxiliary combustion air blown from an auxiliary gas blowing hole 6 into the inside of an FPD cell in the direction of a hydrogen flame 8, that is, toward an extension line A of the central axis of the fuel gas blowing hole 5. Is provided. Specifically, the auxiliary combustion gas blowing hole 6 is formed by being inclined in the direction of the hydrogen flame 8. With this configuration, the auxiliary combustion gas flows in the direction of the hydrogen flame 8, so that the auxiliary combustion gas and the fuel gas are easily mixed, and the formation position of the hydrogen flame 8 is stabilized.
[Selection] Figure 1

Description

  The present invention relates to a flame photometric detector (hereinafter referred to as FPD) for a gas chromatograph.

The FPD is a detector for gas chromatograph, which is characterized in that it has a particularly high sensitivity to sulfur and phosphorus compounds.
The structure of a conventional FPD has been described in detail in Patent Document 1, and the outline thereof will be described below with reference to FIG. In general, a detector for a gas chromatograph is composed of a detector (cell) and an electric system. FIG. 3 shows a schematic structure of a conventional FPD cell in a sectional view.

  As shown in the figure, the FPD cell is composed of a metal cell base 1, a cell outer cylinder 2 covering the upper part thereof, a photometric unit 3 attached to the side of the cell outer cylinder 2, and the like. The space inside the cell surrounded by the upper part of the cell and the cell outer cylinder 2 forms a combustion chamber 4. Hydrogen is introduced as a fuel gas from the lower part of the cell base 1 and air is introduced as an auxiliary combustion gas. The hydrogen is blown into the combustion chamber 4 from the fuel gas outlet hole 5 and the auxiliary gas outlet hole 6 provided in the upper part of the cell base 1. The The fuel gas blowing hole 5 opens at the top of a cylindrical nozzle cylinder 7 protruding upward from the surface where the auxiliary combustion gas blowing hole 6 is provided.

  The column 10 of the gas chromatograph is inserted so that its end reaches the top of the nozzle cylinder 7 and is hermetically fixed by a column connector (not shown) at the lower part of the cell base 1. A mixed gas of carrier gas and sample components (hereinafter referred to as column outflow gas) flowing out from the end of the column 10 is blown out from the fuel gas blowing hole 5 together with hydrogen as fuel, and burns to form a hydrogen flame 8. The light emitted from the hydrogen flame 8 is introduced into the photometry unit 3, where the intensity of light of a specific wavelength derived from the sample component is measured and output as a detection signal. Reference numeral 9 denotes a light-shielding ring that blocks noise emission emitted from the lower part of the hydrogen flame 8.

As described above, the structure in which the nozzle cylinder 7 projecting into the combustion chamber 4 is provided and the hydrogen and the column outflow gas are blown out from a position higher than the auxiliary combustion air has a noise characteristic derived from organic substances in the auxiliary combustion air. It is described in detail in Patent Document 1 that it is effective for separating luminescence from luminescence derived from sample components.
JP 2002-022661 A

  As described above, in the conventional FPD, the fuel gas and the auxiliary combustion gas (air) are blown out in parallel from the respective blowout holes, so that the two gases are gradually mixed by diffusion while forming a parallel flow to form a hydrogen flame. For this reason, when the gas flow rate changes, the position where the hydrogen flame is formed is likely to change. As described above, a light-shielding ring is provided to block noisy light emission derived from organic substances in the air for auxiliary combustion. However, if the hydrogen flame formation position changes, the height of this light-shielding ring must be readjusted. Don't be. The shading ring is inside the FPD cell, and adjustment needs to be performed with the cell outer cylinder removed, which is troublesome and cumbersome. For this reason, there are cases where the FPD is used in a state where adjustment is incomplete, and as a result, a good S / N ratio cannot often be obtained.

  The present invention has been made in view of such circumstances, and provides an FPD with little change in the formation position of hydrogen flame even when the flow rate of fuel gas or auxiliary combustion gas is changed, and thus always has a good S / N ratio. The purpose is to enable analysis by FPD while maintaining the above.

  In order to solve the above problems, the present invention moves the flow of auxiliary combustion air blown from the auxiliary gas blowing hole into the FPD cell in the direction of the hydrogen flame, that is, the extension line of the central axis of the fuel gas blowing hole. A deflecting means for deflecting is provided. Specifically, the auxiliary combustion gas blowing hole is inclined and drilled in the direction of the hydrogen flame, or a deflection member having an inclined surface inclined in the direction of the hydrogen flame is provided above the auxiliary combustion gas blowing hole. With this configuration, the auxiliary combustion gas flows in the direction of the hydrogen flame, so that the auxiliary combustion gas and the fuel gas are easily mixed, and the formation position of the hydrogen flame is stabilized.

  Since the present invention is configured as described above, even when the flow conditions of the fuel gas and the auxiliary combustion gas are changed, there is no need to perform troublesome height adjustment of the light shielding ring, and a good S / N ratio can always be maintained. .

A feature of the FPD provided by the present invention is that a deflecting means for deflecting the flow of auxiliary combustion air blown from the auxiliary gas blowing hole toward the extended line of the central axis of the fuel gas blowing hole is provided inside the FPD cell. It is in the point which constituted.
Therefore, the basic configuration of the best mode is an FPD having such a structure.

FIG. 1 shows an embodiment of the present invention. This figure shows only the upper part of the cell base 1 and its periphery, which are parts related to the present invention, but the overall configuration as an FPD cell is the same as the conventional example shown in FIG. In FIG. 1, the same components as those in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted here.
The difference between the present embodiment and the conventional configuration is that the auxiliary combustion gas blowing hole 6 is inclined toward the hydrogen flame 8, that is, toward the extension line A of the central axis of the fuel gas blowing hole 5. In other words, each outlet hole is formed so that the extension line A of the central axis of the fuel gas outlet hole 5 and the extension lines B and B ′ of the central axis of the auxiliary combustion gas outlet hole 6 intersect.

With this configuration, the fuel gas and the auxiliary combustion gas are blown out toward the intersection C, mixed around the intersection C, and the hydrogen flame 8 is formed around the intersection C.
Since the position of the intersection C is determined by the inclination angle of the auxiliary combustion gas outlet 6 regardless of the flow rates of the fuel gas and auxiliary combustion gas, the formation position of the hydrogen flame 8 is constant regardless of these flow rates. That is, even when the flow rates of the fuel gas and the auxiliary combustion gas are changed, the position of the hydrogen flame does not move. In practice, however, the position of the hydrogen flame 8 varies somewhat according to the flow rate change, but the fluctuation range is smaller than that of the conventional configuration shown in FIG.

FIG. 2 shows two other embodiments of the present invention. Also in this figure, only the upper part of the cell base 1 and its periphery are shown, and the same components as those in FIG. 1 or FIG.
FIG. 4A shows an example in which the surface where the auxiliary combustion gas blowing hole 6 opens is formed in a mortar shape, and the auxiliary combustion gas blowing hole 6 is formed substantially perpendicularly to the mortar-shaped surface. With such a configuration, the auxiliary combustion gas is blown out toward the hydrogen flame 8, so that the same effect as in the case of FIG. 1 can be obtained.
In the present embodiment, if the inclination angle of the mortar-shaped surface is appropriately selected, the upper edge of the mortar also serves as the light shielding ring 9 in FIG. 1, so that the cost can be reduced by reducing the number of parts.

FIG. 2B shows another modification.
This embodiment is an example in which a deflection member 11 for deflecting the flow direction of the auxiliary combustion gas is provided so as to cover the upper side of the auxiliary combustion gas outlet hole 6 formed parallel to the fuel gas outlet hole 5 as in the prior art. The deflection member 11 is formed by inclining the upper part of the conventional light shielding ring 9 inward to form an inclined surface 11a, and the extension lines B and B ′ of the central axis of the auxiliary combustion gas blowing hole 6 pass through the inclined surface 11a. Is arranged.

With such a configuration, the auxiliary combustion gas blown upward from the auxiliary gas blowing hole 6 hits the inclined surface 11a of the deflecting member 11, and the flow direction is changed toward the hydrogen flame 8 as shown by an arrow in the drawing. Therefore, the same effect as in the case of FIG. 1 or 2A can be obtained.
The advantage of the present embodiment is that the present invention can be carried out only by replacing the light-shielding ring 9 with the deflecting member 11 for a conventional FPD cell as shown in FIG. Needless to say, the deflecting member 11 also has a function as the light shielding ring 9.

  The present invention can be used for an FPD for a gas chromatograph.

It is a figure which shows one Example of this invention. It is a figure which shows the other Example of this invention. It is a figure which shows the example of a conventional structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cell base 2 Cell outer cylinder 3 Photometry part 4 Combustion chamber 5 Fuel gas blowing hole 6 Auxiliary combustion gas blowing hole 7 Nozzle cylinder 8 Hydrogen flame 9 Shading ring 10 Column 11 Deflection member 11a Inclined surface

Claims (3)

  A combustion chamber for mixing and burning the column outflow gas, fuel gas, and auxiliary combustion gas, a photometric unit for measuring the intensity of light of a specific wavelength emitted by the flame, and an auxiliary combustion gas outlet for blowing the auxiliary combustion gas into the combustion chamber In the flame photometric detector for a gas chromatograph having a fuel gas outlet for blowing out the column outflow gas and the fuel gas at the top of a nozzle cylinder protruding upward from the provided surface into the combustion chamber, A flame photometric detector comprising deflection means for deflecting a flow of auxiliary gas blown from the auxiliary gas blowing hole toward an extension line of a central axis of the fuel gas blowing hole.   2. The flame photometric detector according to claim 1, wherein the deflecting means is an auxiliary combustion gas blowing hole formed so as to be inclined toward an extension line of the central axis of the fuel gas blowing hole. The deflecting means has an inclined surface inclined toward the extension line of the central axis of the fuel gas outlet hole, and the inclined surface of the auxiliary combustion gas outlet hole is penetrated by the extension line of the central axis of the auxiliary gas outlet hole. The flame photometric detector according to claim 1, wherein the flame photometric detector is a deflection member disposed above.

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