JPH044210Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an instrument for measuring the concentration of available chlorine in a solution. In particular, it relates to a portable, batch-type measuring device that accurately analyzes available chlorine concentration.

Various methods have been proposed and put into practical use to measure the residual amount of chlorine injected for the purpose of sterilizing tap water, sewage, swimming pools, industrial water, etc.
Among them, the iodine titration method, the photoelectric colorimetric method (orthotolidine method), the electrolytic current method, the coulometric titration method, etc. are known. Among these methods, the iodometric titration method is a manual analysis method and is not suitable for mobile use. Furthermore, since the photoelectric colorimetric method measures color changes seen with the naked eye, measurement errors occur in the case of colored sample water. Further, in the coulometric titration method, the structure of the detection end is very complicated, making it inconvenient to handle, and since back titration is performed, considerable skill is required for its use. Therefore, as a portable measuring device that is small and can be easily moved, it is desirable to use one based on the electrolytic current method. Platinum, gold, or silver is used as the electrode in conventional electrolytic current measuring instruments, but in order to keep the diffusion layer of the test liquid constant, a so-called rotating pole is used to rotate the electrode, or the electrode section is Vibrating structures are widely used. When a rotating pole is used, a slip ring is used for contact between the electrode and the lead wire, which has the disadvantage of causing poor contact over time, and when the electrode is vibrated, the diffusion layer is disturbed and is difficult to stabilize. In addition, a diaphragm is used to separate the test liquid from the electrode part, and the chlorine gas in the test liquid passes through a fluorine-based gas permeable membrane, reacts with the electrolyte, and acts on the working electrode (sensing electrode). A container is also known, but it has the disadvantage that the diaphragm is easily clogged.

The present invention is intended to solve the above-mentioned problems. Specifically, positive and negative electrode strips are attached to the core tube which is provided upright inside the container, and the upper and lower electrodes are wound around the core tube. A stirrer with blades was inserted below the core cylinder and above the bottom of the container, suspended from a motor built into the container, and a liquid inlet and a liquid outlet were provided at the bottom and upper side of the container, respectively. This is an effective chlorine concentration measuring instrument featuring:

The drawings show an embodiment of the present invention, and to explain the present invention. In FIGS. 1 and 2, a core cylinder 2 made of a non-conductive material is mounted upright on a holder 3 inside a container 1. , inside this core cylinder 2 there is a container 1
The wing 5 is suspended from the motor 4 built into the upper part of the
A stirrer 6 is inserted, which is attached to the lower end. 7
is the bearing of the stirrer 6. On the surface of the core cylinder 2, electrode strips forming a positive electrode (working electrode) 8 and a negative electrode (counter electrode) 9 are wound alternately in a spiral shape, and positive electrode lead wires 8',
The negative lead wire 9' leads to a power source (not shown) as a shield wire 10 together with the motor connection 4'. As a power source, it is convenient to use a battery for portable use. Note that 11 is a holding part for internally fixing the motor 4, 12 is a connection terminal, and 13 is a top lid part of the container 1. In addition, the lower end portion 14 of the container 1 is opened and serves as a liquid intake port,
A hole 15 is bored in the upper side of the container 1 to serve as a liquid outlet.

Now, a test liquid containing available chlorine is taken as a sample, a chemical such as potassium iodide is added to it, the measuring device is immersed up to the upper part of the liquid outlet 15, and a certain amount of water is applied to the positive and negative electrodes 8 and 9. When electrolysis is performed by applying a DC voltage, the effective chlorine concentration in the solution can be measured by measuring the electrolytic current. At this time, when the motor 4 is driven and the liquid in the container is stirred by the blades 5, the liquid is sucked into the liquid inlet 14, moves upward in the container 1, and is discharged from the liquid outlet 15 as shown by the arrow. A circular flow is formed. Therefore, the diffusion layers formed on the surfaces of the positive and negative electrodes 8 and 9 are made constant, and the effective chlorine concentration can be measured accurately in a stable state.

Note that the shape of the blades 5 is not limited to the cross shape as shown in the drawing, but a normal stirring blade can sufficiently suck the liquid from the bottom of the container, and the shape of the liquid intake port 14 is limited to an open shape as shown in the drawing. For example, the bottom plate may be provided with one or more holes.

The measuring device of the present invention is constructed as described above, so it takes into account poor contact due to sliding between the electrode and lead wire as in conventional rotating electrode measuring devices, and clogging of the diaphragm in diaphragm measuring devices. Therefore, the available chlorine concentration in the solution can be measured accurately over a long period of time.

Furthermore, if a battery or the like is used as the electrode, it can be easily moved depending on the measurement location, so it can be fully utilized as a portable device.

Experimental Example The available chlorine concentration in the solution was measured using the measuring instruments shown in Figures 1 and 2. Available chlorine concentration 0.3ppm, 0.5ppm, manufactured according to JISK0106-1968
1.0ppm, 1M, 5ppm, 2.0ppm, 2.5ppm,
3.0ppm, 5.0ppm, 1 as buffer for each 100ml
100g of KBr in ion exchange water. A sample solution was prepared by adding 2 ml of a solution containing 50 ml of acetic acid. When a DC voltage of 0.5 V was applied to the measuring device and the electrolytic current at each available chlorine concentration was measured while stirring the test solution, the electrolytic current was linear as shown in Figure 3, indicating quantitative properties.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the measuring device of the present invention, FIG. 1 is a sectional view, and FIG. 2 is a bottom view. FIG. 3 is a graph showing the results of an experiment using the same measuring device. 1... Container, 2... Core tube, 4... Motor, 5
...Blade, 6...Stirrer, 8...Positive electrode, 9...Negative electrode, 14...Liquid inlet, 15...Liquid outlet.

Claims (1)

[Scope of utility model registration request] A winding positive and negative electrode strip is attached to a core cylinder provided upright inside the container, and the wire is suspended from a motor built into the container and is placed below the core cylinder and above the bottom of the container. An instrument for measuring the concentration of available chlorine in a solution, characterized in that a stirrer equipped with blades is inserted into the container, and a liquid inlet and a liquid outlet are provided at the bottom and upper sides of the container, respectively.