JPH0328367Y2 - - Google Patents

Description

[Detailed description of the device] The device can easily measure various electrochemical quantities of various solutions, such as pH, ionic activity, redox potential, and conductivity, using a single electrode for multiple items. Regarding composite electrodes.

Conventionally, electrodes (sensors) that respond monopotentially to each measurement item have been used to measure the above quantities, but recently there has been an increase in the desire to measure multiple items simultaneously. In response to this, a device has been provided in which a plurality of electrodes are housed in one electrode holder and used as one unit.

In addition, for one measurement item, for example, in the case of PH measurement, an indicator electrode such as a glass electrode, a reference electrode that is a reference potential, and two or three detection electrodes of a temperature sensing element that compensates for temperature characteristics, Since an element is required, many electrodes that are constructed by integrating these elements have been devised and commercially available. Currently, most of the so-called composite electrodes are of this type, and are integrated with electrodes and elements corresponding to a single measurement item.

However, it is extremely difficult to form a composite electrode by integrating electrodes and elements corresponding to a plurality of measurement items due to the following points, and no product has been provided on the market yet.

That is, 1. There are many outer cylinders and support tubes that support each electrode and element, making the structure complex.

2 It is technically difficult to draw out the lead wires of each electrode through the narrow space between the support tubes,
Furthermore, these lead wires must be sufficiently electrically insulated and electrostatically shielded from each other, and
It must be treated to prevent it from being corroded by internal fluids, etc.

3. The arrangement of each electrode and element at the detection end must be such that they do not affect each other and have complete contact with the test liquid.
Furthermore, it is difficult due to manufacturing technology to arrange the liquid junction of the reference electrode in the narrow detection end.

According to etc.

On the other hand, there is a demand from the market that users, such as hydroponic farmers or horticulturists, who have knowledge of the object to be measured but do not have knowledge of measurement technology, can easily, safely, and reliably use it. It is designed to be easy to handle and measure, and
The emergence of inexpensive products is expected. For this purpose, the electrode holder mentioned above, which is used by attaching multiple electrodes, is difficult to assemble and handle, making it unsuitable for general users. There are problems such as the large size of the container and the need for a large amount of sample liquid to be tested.

In view of these points, the inventors, etc., have made the above requests and the various problems to be solved.
As a result of various studies, we have found that by applying some of the technology previously proposed by the applicant, we have been able to solve the main problems and provide a composite electrode for simple measurement that can meet the needs of the market. Ta.

FIG. 1 is a longitudinal sectional view showing an embodiment of a composite electrode for simple measurement according to the present invention. The one in this picture is PH
Glass electrode for measurement, solid electrode for ion activity measurement 2
Although this is an example in which the seed and reference electrodes are integrated, it is of course possible to provide a platinum electrode for measuring redox potential, a temperature sensing element for temperature compensation, etc. in place of the solid electrode.

In the figure, reference numeral 1 denotes an outer cylinder, which is made of a material such as glass or plastic that is not corroded by the test liquid or internal liquid. Then, the tip part is made thicker by increasing the wall thickness, and a solid electrode 2 (two in the figure) for measuring ion activity is embedded in this part, and the end of the solid electrode is exposed at the tip. Arrange it like this.
The lead wire 3 of each electrode is drawn out from the embedded part of the outer cylinder 2 into the outer cylinder, and the surface of the drawn out part is electrically insulated, and at the same time, the lead wire 3 of the electrode is prevented from being corroded by the internal liquid of the comparison electrode filled in this space. , coating with corrosion-resistant and insulating material. For example, the process of applying glass coating to the surface of the lead wire, which was disclosed by the present applicant in Utility Model Publication No. 48-151, is one example.

A glass electrode 4 is coaxially inserted into the outer cylinder 1, its PH sensitive membrane part 5 protrudes from the tip of the outer cylinder 1, and the support tube part is supported between the outer cylinder and the outer cylinder through a spacer 6. be done. The spacer 6 is a disc made of corrosion-resistant material.
The space between the outer cylinder 1 and the glass electrode 4 is maintained airtight, and one or more small through holes 7 are formed in the vertical direction on the plate, and a porous liquid junction member 8 is fitted into the hole to form a reference electrode. The structure is configured to perform a liquid junction. In the space between the outer cylinder 1 and the glass electrode 4, an internal electrode 10 as a reference electrode is disposed, and if the internal liquid 11 is filled, each member 6, 7, 8, 9, and 10 can be compared. An electrode is configured. This configuration was proposed by the applicant in 1983.
This has already been proposed in No. 5524.

Reference numeral 9 denotes a protrusion having a fan-shaped cross section provided on the tip edge of the outer cylinder 1, which protects the sensitive membrane portion 5 of the glass electrode and the solid electrode 2 from mechanical impact. Note that the glass electrode 4 has an internal electrode 1 inside the support tube.
2 and internal liquid 13 are provided and filled.

Since the lead wires of the glass electrode and the reference electrode also pass through the internal liquid as described above, they are subjected to corrosion-resistant and insulating treatment. The upper end of the outer cylinder 1 and the upper end of the glass electrode 4 are sealed after being filled with the internal liquid, and each lead wire is connected to a multicore cable 14 and pulled out, and the connecting portion is housed in an electrode cap 15. The other end of the multicore cable has an electrode terminal 1 connected to the measuring device.
Attach 6. Reference numeral 17 denotes a small pore for allowing the internal liquid of the reference electrode and the space above the liquid to breathe.

FIG. 2 shows the detection end of the electrode shown in FIG. 1, viewed from the bottom.

By configuring as described above, 1. It is possible to rationally arrange a large number of electrodes, elements, etc. in a narrow space without affecting each other.

2. The entire electrode can be assembled compactly and robustly.

3. The lead wire draw-out part can be made extremely thinner than the case where the lead wire is passed through a conventional glass capillary tube, etc., and is flexible, so it is easy to assemble and can withstand shocks.

With these features, it is possible to obtain a composite electrode that can be easily handled even by a user with no knowledge of measurement techniques.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the composite electrode for simple measurement according to the present invention. FIG. 2 is a view of the detection end section viewed from the bottom. In each figure, 1... outer cylinder, 2... solid electrode, 3...
Solid electrode lead wire, 4...Glass electrode, 5...Glass electrode sensitive membrane portion, 6...Spacer, 7...Liquid junction small hole, 8...Liquid junction member, 9...Outer cylinder projection, 10
...Internal electrode of the comparison electrode, 11...Internal liquid of the comparison electrode, 12...Internal electrode of the glass electrode, 13...
Internal liquid of glass electrode, 14...Multi-core cable, 1
5... Electrode cap, 16... Electrode terminal, 17...
...stomata.

Claims (1)

[Scope of utility model registration request] The internal electrode of the comparison electrode, which is placed in the space between the glass electrode for PH measurement placed in the center and the outer tube coaxially provided on the outer periphery of the support tube of this glass electrode, and the internal liquid, and the glass electrode. A spacer interposed between the detection end of the electrode and the lower end of the outer cylinder, provided with one or more small holes, and filled with a liquid junction member; one or more solid electrodes or temperature-sensitive elements with exposed ends; lead wires that are drawn out from each of these electrodes and elements and have a corrosion-resistant and electrically insulating surface treatment applied to the portions through which the internal liquid passes; A composite electrode for simple measurements consisting of a multi-core cable that connects these lead wires inside the electrode cap, and a connection terminal.