JPH028207Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a silver monochloride reference electrode assembly, which enables long-term storage of the known silver monochloride reference electrode and immediate operation during use.

In a known silver monochloride reference electrode, the center electrode is coated with alkali chloride gel in order to keep the chlorine ion concentration around the center electrode constant and avoid the influence of the ion concentration in the liquid to be measured. If such electrodes are not used immediately after fabrication, they must be preserved by immersing them in an aqueous alkali chloride solution until they are used, in order to prevent the gel from deteriorating due to drying, etc., making storage and transportation extremely difficult. It was inconvenient.

These problems are not limited to those with a structure in which a counter electrode is provided integrally, but are also common to reference electrodes that are used alone. This has been a major difficulty in microelectrodes that can be embedded in microelectrodes (for example, electrode assemblies with a counter electrode outer diameter of about 1 mm). In such electrode assemblies, methods that have been used in the past in reference electrodes to eliminate the above-mentioned inconveniences, although imperfect in terms of sealability, have been used, such as the means of covering the tip of the electrode assembly with a rubber cap. It could not be applied due to the difficulty of removal operation.

The present invention was proposed to solve the above-mentioned inconvenience, and its gist is to coat the periphery of a central silver electrode with a silver chloride layer formed on its surface with an alkali chloride-containing gel, and to The electrode assembly has a structure in which a silver monochloride reference electrode is separated from a tubular counter electrode on the outer periphery by an insulating tube, and an extension and sealing part is provided integrally with the tube at the tip of the insulating tube.

Hereinafter, the present invention will be explained in more detail with reference to illustrated embodiments. FIG. 1 is a side sectional view of an electrode assembly embodying the present invention, in which 1 is a silver center electrode (for example, a fine silver wire with an outer diameter of 0.2 mm) 11 is a silver chloride layer formed on the surface of the silver electrode; 12 is an insulating coating. Around the silver chloride layer 11 is an alkali chloride-containing gel 2.
(e.g. 3N NaCl, 2% agar, 2% gelatin)
(contains aqueous gel).

The covering body is an insulating tube body (for example, a glass tube with an outer diameter of 1 mm and an inner diameter of 0.6 mm) 3, and a tubular counter electrode 4 on the outer periphery.
(for example, a stainless steel tube with an outer diameter of 1.2 mm), and the counter electrode 4 is electrically connected to the cover 51 and the lead wire 5 near its upper end. The upper end openings of the tubular counter electrode 4 and the insulating tube body 3 are embedded together with the central silver electrode 1 and the lead wire 5 in an insulating resin layer 6 (usually cast epoxy resin).

Here, the insulating tubular body 3 is integrally formed with an extending portion 31 and a sealing portion 32 that protrude from a portion covered with the tubular counter electrode 4, and the inside thereof is filled with the gel 2.

After long-term storage, the electrode assembly with the above structure will
The insulating tube 3 is connected to the second electrode at its tubular counter electrode 4 envelope boundary 33.
By cutting as shown in the figure, it became possible to operate immediately, and since the chlorine ion concentration was constant, it was confirmed that the electromotive force was stable. Although the sealing portion 32 is shown in the drawing as a glass seal, other sealing means such as resin sealing may be used instead. In addition, in the case of melt sealing, the tip of the filled gel 2 may become carbonized (scorched) and turn black, or a void may be formed, but since the extended portion 31 is to be cut and discarded, use of the electrode assembly is prohibited. There are no problems with this.

Further, if the insulating tube body 3 is provided with a cutting notch 34 at its cutting boundary 33 (exposed portion from the tubular counter electrode), the cutting operation during use becomes easier. The notch 34 may be a single flaw or may be a thin groove extending all around the circumference.

As described above, the practical effects of the present invention are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an electrode assembly according to an embodiment of the present invention, and FIG. 2 is a side sectional view of the assembly shown in FIG. 1 when it is cut. 1... Silver center electrode, 2... Alkali chloride gel,
3...Insulating tube body, 4...Tubular counter electrode.

Claims (1)

[Claims for Utility Model Registration] 1. A silver electrode whose surface is coated with alkali chloride gel around a central silver electrode on which a silver chloride layer is formed, and where the coating is separated from a tubular counter electrode on the outer periphery by an insulating tube. An electrode assembly for a silver chloride reference electrode in which a stretched and sealed portion is provided at the tip of the insulating tube integrally with the tube. 2. The electrode assembly according to claim 1, wherein a cutting notch is provided in the exposed portion of the insulating tube from the tubular counter electrode.