JPS5925178B2 - Acid self-contained analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an acid self-contained analyzer equipped with an ozone generator and capable of producing the necessary acid by itself using nitrogen oxides produced together with ozone from the generator.

For analyzers that require acid for pH (hydrogen ion concentration) adjustment, chemical reactions such as neutralization, or acid cleaning, the dangerous acid must be prepared and injected into the analyzer manually each time an analysis is performed. This is common practice and has become a serious problem.

Particularly in process automatic analyzers, a reagent tank or the like is installed to enable automatic acid injection intermittently using a drop or a reagent pump, but replenishing acid into the reagent tank still requires manual labor. Therefore, if the capacity of a tank or the like is increased in order to reduce the frequency of replenishment, the installation space will be occupied, which is undesirable from the viewpoint of safety management of storage of hazardous materials. Therefore, the present invention provides an acid self-sufficient analyzer that does not require external acid replenishment and produces the necessary acid on its own, thereby solving the problems associated with the external replenishment method. The purpose is to provide

Therefore, in the present invention, an ozone generator is attached, and the generator generates nitric acid from nitrogen oxides generated together with ozone, and the resulting acid is utilized. Hereinafter, one embodiment of the present invention will be described with reference to the drawings. First, an ozone generator will be explained with reference to FIGS. 1 and 2. As shown in Fig. 1, a dielectric material 3 is placed between a pair of electrodes 1 and 2, and an alternating current voltage is applied between the electrodes 1 and 2 to generate a silent discharge in the gap 4 between the electrodes. Nitrogen oxides are produced along with ozone in the air. FIG. 2 is a structural diagram of a cylindrical ozone generator (Siemens type) known as a practical type based on the principle shown in FIG. Reference numeral 11 denotes a glass tube with one side open, and one inner surface is made conductive by metal vapor deposition to form a high-voltage side electrode, and an alternating current voltage is applied to this electrode from an external transformer through a bushing 12.

A cylindrical low voltage electrode 13 made of stainless steel also serves as a container, and a discharge gap 15 is uniformly formed between it and the glass tube 11 by a spacer 14 as shown in the figure.

That is, when an AC voltage of 5 to 15 kV is applied between the electrodes 11 and 13 and air is blown from the air inlet 16, the air outlet 17
Air containing ozone and nitrogen oxides generated by the discharge is extracted from the chamber. ．． FIG. 3 is a diagram showing the structure of the acid-producing part.

The ozone generator mentioned above produces air containing ozone and nitrogen oxides, but since ozone is unnecessary at this time, the air taken out from the ozone generator is
After ozone heated to 0° C. is decomposed into oxygen, air N2O5 containing nitrogen oxides is brought into contact with water H2O in a gas-liquid contact tank. Then, it immediately dissolves in water and N2O, +
Nitric acid solution 2HN03 is obtained by the reaction formula H2O→2HN03. FIG. 3 is a block diagram of this device, where 21 is an ozone generator that generates the ozone and nitrogen oxides mentioned above, and 22 is an AC power source that supplies AC voltage to this ozone generator 21. The generator 21 introduces clean air passed through an air filter 24 by a suction device 23 consisting of a pump or the like. Air containing ozone and nitrogen oxides from the ozone generator 21 is introduced into the heater 25, where the ozone is oxygenated, and then in the gas-liquid contact tank 26, the nitrogen oxides are brought into contact with water to form nitric acid. generated. In the apparatus shown in FIG. 3, the amount of nitric acid generated can be freely selected depending on the capacity and type of the ozone generator 21, the applied voltage, the air temperature, and the amount of air.

For example, in the case of a 100W class ozone generator, 0 per hour
．． 19 of nitric acid, approximately 2.6 per minute
A concentration of ×10 −4 M01/l is obtained. Note that the gas-liquid contact tank 26 does not need to be provided separately depending on the type of analyzer, and can be replaced by the analyzer's PH adjustment tank, a tank for chemical reactions such as neutralization, or an acid cleaning tank. It is. The analyzer utilizes the nitric acid solution obtained with the apparatus shown in FIG. Next, an example in which the present invention is applied to a reagent-free residual chlorine meter used in waterworks processes will be described with reference to FIGS. 4 and 5. The conventional type of chlorine meter has the following drawbacks. That is, FIG. 4 shows the PH characteristics of the conventional chlorine meter, where is the indicated value. As is clear from this characteristic diagram, if the sample PH exceeds the range of 5.8 to 7.2, there will be an indication error, and the actual sample PH may exceed 7.2. In the case of chlorine meters, this is considered to be one of the drawbacks. However, if the above-mentioned acid self-producing structure is adopted, this drawback can be easily overcome. FIG. 5 is a block diagram of an acid self-sufficient PH control type reagentless residual chlorine analyzer that eliminates the above-mentioned drawbacks. 21-25
are the same as those shown in Fig. 3, and each comprises an ozone generator, an AC power source, a suction device, an air filter, and a heater, each of which constitutes an acid producing section.

26 is a mixing tank having a PH electrode for PH control and a stirrer 28, which corresponds to the gas-liquid contact tank in FIG. Air containing nitrogen oxides is introduced from the container 25.

The conduit 30 is provided with a control valve 31 such as a solenoid valve for opening and closing the conduit 30 to perform pH control. 32
is a polarographic measuring tank for measuring chlorine concentration, which has a pair of electrodes 33.

In this apparatus shown in FIG. 5, the electrode 27 measures the pH of the sample introduced into the mixing tank 26 by the sample pump 29, but at this time, if the sample containing the sample is on the real alkaline side than the preset pH value. When this happens, the control valve 31 is opened by a PH controller (not shown), and a nitrogen compound that undergoes nitrification is introduced into the mixing tank 26, thereby lowering the pH value in the mixing tank 26.

This makes it possible to maintain the range within which no indication error occurs. In the case of a waterworks process, the sample PH never becomes more acidic than the range in which no indication error occurs, so it is practically sufficient to simply control the pH using acid to prevent it from becoming alkaline.

As described above, according to the present invention, the acid self-sufficiency configuration solves the problems associated with the external acid supply system, and when applied to a residual chlorine meter, the performance can be improved while taking advantage of the reagentless feature. It is also possible to improve the

[Brief explanation of the drawing]

Figure 1 is a diagram of the principle of ozone and nitrogen oxide generation, Figure 2 is a structural diagram of a practical ozone generator based on the principle of Figure 1, Figure 3 is a diagram of the configuration of the acid producing section, and Figure 4. 5 is a PH characteristic curve diagram of a conventional reagentless residual chlorine meter, and FIG. 5 is a block diagram of a PH control type reagentless residual chlorine meter as an embodiment of the present invention. 21... Ozone generator, 22... AC power supply, 23... Suction device, 24... Air filter, 25... Heater, 26 ...gas-liquid contact tank (mixing tank), 2...PH electrode for PH control,
28... Stirrer, 29... Sample pump, 31... Control valve, 32... Polarographic measurement tank.

Claims (1)

[Claims] 1. An ozone generator that generates nitrogen oxides along with ozone from the air by silent discharge, and the ozone and nitrogen oxides generated by this ozone generator are introduced and the ozone is oxygenated by heating. A heating device, a mixing tank having a pH electrode for pH control and a stirrer and to which tap water is supplied as a sample by a pump, and a pipe line for introducing nitrogen oxides from the heater into this mixing tank. When the pH electrode for pH control detects that the water from the tap water introduced into the mixing tank is more alkaline than the preset pH value, it is controlled to open and an appropriate amount of nitrogen oxidation is applied to the mixing tank. A self-contained acid analyzer comprising a control valve that adjusts the pH value of the water by supplying a substance, and a polarographic measuring tank for measuring chlorine concentration that measures the chlorine component contained in the water adjusted in the mixing tank. .