JPS5979839A - Gas control apparatus for atomic absorption analytical apparatus - Google Patents

Abstract

PURPOSE:To avoid a backfire and to prevent soot generation in extinguishing a flame, by a method wherein the supply of nitrous oxide is stopped while air is sent when power failure occurs during the combustion of a nitrous oxide- acetylene flame and the supplies of both of them are subsequently stopped in the order of acetylene and air. CONSTITUTION:An air supply pipe P1' having a solenoid valve V1 arranged thereto and a nitrous oxide supply pipe P1'' having a solenoid valve V2 arranged thereto are connected to a combustion aid gas introducing pipe P1 which is, in turn, opened to a burner B through a solenoid valve V3 and a combustion gas introducing pipe P2 receiving the supply of acetylene is opened to the burner B through a solenoid valve V4. When power failure occurs during the combustion of a nitrous oxide-acetylene flame, the valve V2 is closed to stop the supply of nitrous oxide and the valve V1 is opened to lower a combustion speed while sending air. Subsequently, the valves V4, V3 are closed so as to leave a predetermined delay time and the supplies of both of them are stopped in the order of acetylene and air to extinguish the flame. As a result, a backfire is avoided and soot generation can be prevented.

Description

[Detailed description of the invention] This invention allows light to pass through a layer of atomic vapor.

The present invention relates to a scum control device in an atomic absorption spectrometer that excites atoms in the ground state and utilizes the strength of the resulting light absorption to perform qualitative and quantitative analysis.

The sample is converted into U and atomized by burning it in a burner using a mixture of combustion gas and auxiliary gas.

In a so-called flame atomic absorption spectrometer, it is necessary to select a frame suitable for the element to be measured, and there are four types of υ frames (
Nitrous oxide - acetylene flame, air - acetylene flame, air - hydrogen flame, argon - hydrogen flame) are used by switching as appropriate, but especially when using a nitrous oxide - acetylene flame, its combustion speed is very fast, so igniting this mixture directly, or stopping the supply of nitrous oxide and acetylene at the same time when it is extinguished, will cause backfire, damaging the burner and forcing the user to stop the ignition. At times, air was supplied before nitrous oxide was supplied, and when the flames were extinguished, the supply of nitrous oxide was switched to air before the supply of nitrous oxide was stopped. However, in the event of an abnormal situation where the power supply is cut off due to a power outage while the nitrous oxide-acetylene flame is burning, these operations may not be carried out, resulting in backfires or large amounts of soot. .

In view of the above circumstances, it is an object of the present invention to provide a gas control device for an atomic absorption spectrometer that is improved so that even if the power supply is cut off for some reason, no backfire occurs or soot is generated when the flame is extinguished. It is something to do.

In the scum control device of the present invention, if the power supply is cut off due to a power outage or the like during combustion of the nitrous oxide-acetylene flame,
First, the supply of nitrous oxide residue is stopped and at the same time air is supplied to the burner to create an air-acetylene flame, then the supply of acetylene residue is stopped, and finally the supply of air is stopped.

The present invention will be explained below based on the drawings.

FIG. 1 is an explanatory diagram showing an outline of a gas control device in an atomic absorption spectrometer according to the present invention.

In the figure, (Pl) is a solenoid valve (Vl) on the pipe.
An air supply pipe (Pl) with a solenoid valve (■2) installed on the pipe, and a nitrous oxide supply pipe (PI) with a solenoid valve (■2) installed on the pipe.
A combustion auxiliary gas introduction pipe where the gases are merged and opened to the burner (B), and this introduction pipe (PI) is equipped with a solenoid valve (3).

(T2) is a combustion gas introduction pipe through which acetylene is supplied and opens into the burner (B) via a solenoid valve (4). Here, the solenoid valve (vl) is a solenoid valve that is closed when energized and open when not energized, and (V2) to (V4) are solenoid valves that are open when energized and closed when not energized. Further, N solenoid valves (V3), (V4) and K grouper (TI) (T2) are connected, and their closing operation is delayed for a set fixed period of time when switching from open to closed.

The relationship between the delay times between the two is as follows.

Tl < T2 Solenoid valve (Vl) (V2) (V3) of the gas control device in the atomic absorption spectrometer of the present invention configured as described above
(■4) and the flame sequence are shown in Figure 2. In Figures 1 and 2, when the power switch is turned on and the nitrous oxide-acetylene flame is ignited by normal ignition operation, the solenoid valves (■2) (V3) (V
4) C open (D state-4c'6, T11, bar
f-CB) VC nitrous chloride-acetylene flame is respectively fed through the inlet pipe (Pl) (T2). In this state, if the power supply is cut off due to a power outage or the like, the solenoid valve (2) immediately closes and at the same time the solenoid valve (Vl) closes. Then, after the delay time set by the timer (T1) has elapsed, the solenoid valve (4) is closed, and the supply of acetylene is stopped. Then, there is a timer (T
After the delay time set in 2) has elapsed, the solenoid valve (■3) closes.

The air supply is stopped and the combustion is extinguished.

As explained above, this invention supplies air instead of nitrous oxide and temporarily removes nitrous oxide even when the flame is extinguished in an abnormal situation such as when the power supply is cut off due to a power outage or the like during combustion of a nitrous oxide-acetylene flame. - By reducing the combustion speed as an acetylene flame and then cutting off the supply of acetylene and then air, it is possible to avoid backfire and eliminate the inconvenience of clogging the burner due to the generation of a large amount of soot when the flame is extinguished.

In the above example, the case where the power supply was cut off due to a power outage was explained, but the case where the pressure monitor detects that the gas pressure supplied has become extremely low, or when the flame monitor irradiates the photo sensor is explained. Even when it is detected that the light has been cut off, the flame can be safely extinguished using the same principle if the V power supply circuit is cut off based on these detection signals.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an outline of a gas control device for an atomic absorption spectrometer according to the present invention, and FIG. 2 is a diagram showing a sequence of the device shown in FIG. (PI)... Combustion auxiliary waste introduction pipe (P2)... Combustion waste introduction pipe (Tl) (']'2)... Timer (
Vt)...Solenoid valve that closes when energized and opens when de-energized (V2
) (V3) (V4)...Solenoid valve that opens when energized and closes when not energized (B)...Pernat...

Claims (1)

[Claims] 1. Atomic absorption spectrometry comprising a combustion sludge introduction pipe that opens into a burner and supplies acetylene, and an auxiliary combustion sludge introduction pipe that joins an air supply pipe and a nitrous oxide supply pipe and also opens into the burner. In the apparatus, the combustion gas inlet pipe, the nitrogen oxide supply pipe, and the combustion auxiliary gas inlet pipe are each provided with a solenoid valve that opens when energized and closes when not energized, and the air supply pipe is provided with a solenoid valve that opens when energized and closes when energized.
A solenoid valve that opens when power is not energized is provided, and a timer is provided for each solenoid valve that delays the closing operation for a certain period of time when switching from open to close of the solenoid valve provided in the combustion gas introduction pipe and the combustion auxiliary gas introduction pipe, and the delay time of both is provided. 1. As a solenoid valve for the combustion gas introduction pipe, when the power supply is cut off during combustion in the burner. (1) At the same time that the introduction of crab suboxide to the burner is stopped, the introduction of air to the burner is started. (2) Then, after the delay time set by the timer has elapsed, the introduction of combustion scum to the burner is stopped. (3) A gas control device for an atomic absorption spectrometer, characterized in that the flame is extinguished in the order in which air is stopped being introduced into the burner after a delay time set by a timer has elapsed.