JPS5812131Y2 - Free available chlorine measuring device - Google Patents

Description

[Detailed description of the invention] The present invention is a method of mixing a reagent containing bromide ions with test water, and determining the concentration of free available chlorine in the test water using a pair of electrodes placed in the mixed water. This relates to a chlorine measuring device.

In a conventional device of this type, a rotating electrode and a counter electrode are immersed in the mixed water, and free available chlorine is determined from the current flowing when a constant voltage is applied between these electrodes.

Due to the use of rotating electrodes, the configuration of this conventional device is complex.

Also, because it uses a current detection method, rangeability is low.

The purpose of this invention is to have a simple configuration and rangeability (
An object of the present invention is to provide a free available chlorine measuring device having a large measurement range (or measurement range).

The present invention will be explained in detail below with reference to the drawings.

The figure is a basic configuration diagram showing an embodiment of the free available chlorine measuring device according to the present invention.

In the figure, 1 is a liquid tank, 2 is a mixed water of a reagent containing bromide ions and test water, 3 is a platinum electrode immersed in the mixed water 2,
4 is a bromide ion activity electrode immersed in the mixed water 2; 5 is a high input impedance amplifier that outputs a signal corresponding to the potential difference between the electrodes 3 and 4;

Mixing a reagent containing bromide ions with test water will reduce the amount of C in the test water.
r> are all replaced with Br2.

That is, Br"" is added in excess and mixed so that all C12 undergoes the reaction CJ2+2Br-=Br2+2Ct.

The potentials generated on the platinum electrode 3 and bromide ion activity electrode 4 immersed in this mixed water 2 are respectively Ept.

Ebr, E p t and E b r are expressed by the following equations.

However, E: constant rp Ebr, c: constant R: gas constant T: absolute temperature of mixed water 2 F: Faraday constant CB, J: activity concentration of Br2 in mixed water 2 [B
r-J: Activity concentration of Br- in the mixed water 2 Therefore, the amplifier 5 outputs a signal corresponding to the magnitude represented by Em in the following equation.

Em””Ept Ebr -T =E.

+-Jn [Br 2 JF However, Eo=Eorp-Eb7. c The concentration of mixed water 2 medium Br2 is C12 in the test water before mixing.
Since it corresponds to the concentration of C12 in the sample water, Em in the above equation (3) also indicates the concentration of C12 in the sample water.

Therefore, the concentration of C12 in the sample water can be determined from the output signal of the amplifier 5.

Further, in this device, the output signal of the amplifier 5 is C
Since the concentration changes logarithmically with respect to the linear change in concentration of 12, the rangeability (or measurement range) can be widened.

However, since the presence of Br- has no effect on the output signal of the amplifier 5, the amount of the reagent mixed may be any amount as long as Br- is added in excess.

The table below is a C12 concentration measurement result table showing the results of measuring the C1z concentration in the mixed water 2 using the above-mentioned embodiment of the present invention.

The buttons in the table below include, in addition to the electrode combination consisting of the platinum electrode 3 and bromide ion activity electrode 4 (hereinafter referred to as the "third electrode combination"), the electrode combination consisting of a platinum electrode and a silver-silver chloride electrode ( For the electrode combination (hereinafter referred to as "first electrode combination") and the bromide ion active electrode and silver-silver chloride electrode (hereinafter referred to as "second electrode combination"), the bromine concentration in the mixed water 2 was set to 40 g/l. .

80 g/l and in each case C12
The concentration is 0.025 ppm, 0.1 ppm, 0.5
ppm.

1, Oppm, 5.0 ppm, and 10.0
The actual measurement results are shown in mV while changing the voltage in ppm.

In addition, during this measurement, the temperature and pH were each 27°C.
and is adjusted to about 5-5.2.

According to the table below, the measurement results for the first to third electrode combinations correspond to equations (1) to (3) above, and only in the case of the third electrode combination is the Br-concentration Accurate CI without being influenced by! It is easy to understand that two concentrations can be measured.

As explained above, according to the present invention, it is possible to realize a free available chlorine measuring device that has a simple configuration and allows a wide range of range abilities to be selected.

[Brief explanation of the drawing]

The figure is a basic configuration diagram showing an embodiment of the free available chlorine measuring device according to the present invention. 1...Liquid tank, 2...Mixed water, 3...Platinum electrode, 4
...Bromide ion activity electrode, 5...Amplifier.

Claims (1)

[Scope of utility model registration request] In a free available chlorine measuring device that mixes a reagent containing bromide ions with test water and determines the concentration of free available chlorine in the test water using a pair of electrodes placed in the mixed water, the bromide ion activity electrode and A free available chlorine measuring device characterized in that it is configured to use a platinum electrode as a pair of electrodes and to determine the free available chlorine concentration in sample water from the potential difference generated between these electrodes.