JP2631831B2 - Ion concentration measurement sensor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ion concentration measurement sensor that measures the ion concentration of a solution such as pH.

[Conventional technology]

A conventional example of the ion concentration measurement sensor is disclosed in, for example, Japanese Patent Application Laid-Open No. 58-61457.

FIG. 5 shows an ion concentration measurement sensor according to this publication. In FIGS. 5A and 5B, reference numeral 60 denotes two thermoplastic resin cylinders 61 and 62 and flanges 63 and 64 thereof. Is a cylindrical support integrally formed by ultrasonic welding. 65 and 66 are spacers made of a thermoplastic resin. 67
Is a rubber gasket, as shown in FIG. 3C, a glass electrode 68 described later, an internal electrode 84 of a comparative electrode 80, a protective tube 89,
Through holes 67a through which the internal liquid supply tubes 92 are inserted
~ 67d.

Reference numeral 68 denotes a glass electrode, which comprises a sensing portion 69, a cap 70, a contact 71, O-rings 72, 73, etc., which is attached to a space 62a formed in the cylindrical body 62, a conductive rubber 74, a contact 7
5 is connected to the core of the cable 76. The cable 76 has each core wire connected to the internal electrode 84 of the comparison electrode 80, the temperature measuring body 90, the liquid earth 91, etc., and a cap 77 of a thermoplastic resin,
The gasket 78, the filler 79, and the like form a watertight structure and are integrated with the cylinder 61.

Reference numeral 80 denotes a reference electrode, the liquid junction 81 of which is screwed to the cylinder 62 via a cap 82, an O-ring 83, and the like, and a contact 85 of the internal electrode 84 is connected to a cable via a conductive rubber 86. It is connected to a contact 88 of a core wire 87 of 76. Reference numeral 89 denotes a protective tube that stores the temperature measuring element 90 and the liquid earth 91. 92
Is an internal liquid supply tube, which is provided inside the cylinder 61,
A flow path for supplying the internal liquid to the internal liquid storing section 93 formed in the cylindrical body 62 is formed.

[Problems to be solved by the invention]

In the conventional ion concentration measuring sensor, the inside of the cylindrical support 60 is divided into two upper and lower spaces by a rubber gasket 67, and the upper space (inside the cylindrical body 61) has a core wire of the cable 76. And, glass electrode 68, comparative electrode 80,
While a connection portion with a lead wire from a sensor portion such as a temperature measuring body 90 is provided, the sensor portion and the internal liquid storage portion 93 and the like are provided in a lower space (in the cylindrical body 62). The gasket 67 also has four through holes 67a to 67d for inserting the glass electrode 68, the internal electrode 84 of the comparative electrode 80, the protective tube 89, and the internal liquid supply tube 92, respectively, so that the sealing area is extremely small. It is large and has a drawback that it lacks water tightness.

And the upper space where the connection portion is provided,
Because it is formed only by the cylinder 61, it is unprotected against disturbances such as electrostatic induction.
If you touch 61, the measured value may fluctuate greatly.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide a high-performance ion concentration measurement sensor that has reliable watertightness and is not affected by disturbance.

[Means for solving the problem]

In order to achieve the above object, an ion concentration measurement sensor according to the present invention is an ion concentration measurement sensor in which a sensor portion such as a sensitive portion of a glass electrode is formed at a lower end portion of a cylindrical support. An annular partition is provided inside the cylindrical support, a lower portion of the annular partition is connected to an inner portion of the cylindrical support, and a signal extracting member from the sensor portion to the outside is provided in the annular partition. While providing a cable connection portion with the lead-out cable, an internal liquid storage portion connected to the internal space of the reference electrode is formed between the annular partition and the cylindrical support, and the internal liquid is stored in the internal liquid storage portion. It is characterized in that the surface is filled so as to be higher than the cable connection portion, and the cylindrical support and the annular partition are arranged concentrically at the outer peripheral position of the cable connection portion.

[Action]

In the ion concentration measurement sensor according to the present invention having the above characteristic configuration, a sensor portion such as a sensitive portion of a glass electrode is formed at a lower end portion of the cylindrical support, and the cylindrical support is provided above the sensor portion. An annular partition wall is provided inside, and a lower portion of the annular partition wall and an inner portion of the cylindrical support are connected to each other, so that a sealing area can be significantly reduced without using a gasket having a plurality of through holes. And therefore,
Watertightness is improved.

In addition, a cable connection portion between a signal extraction member from the sensor portion and a cable drawn out to the outside is provided in the annular partition, and the internal liquid storage portion surrounded by the annular partition and the cylindrical support is connected to a cable. The inner liquid reservoir is formed in an annular shape at the outer peripheral position of the part, and the internal liquid storage part is configured so that the liquid level of the internal liquid is higher than the installation position of the cable connection part. It can protect against disturbances such as induction. In particular, the entire outer periphery of the cable connection portion, which was conventionally unprotected against external disturbance, is surrounded by the internal liquid, so that the influence of external disturbance at this portion can be effectively prevented, and highly accurate ion concentration measurement can be performed. .

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 (A), 1 (B), and 1 (C) show an embodiment of the present invention. In this figure, reference numeral 1 denotes a cylindrical support, which comprises an upper cylindrical body 2 and a lower cylindrical body 3; Are fused together by ultrasonic welding, and reference numeral 4 denotes a fused portion. This cylindrical support 1
The outer liquid junction 29 of the glass electrode 8 and the comparison electrode 23
Concave portions 5 and 6 for detachably mounting (all described later) are formed, and above these concave portions 5 and 6,
An annular partition 7 is integrally formed inside the tubular support 1. That is, the lower part of the annular partition 7 and the cylindrical support 1
And the inner part of the cylindrical body 3 is connected. Further, the cylindrical body 2 of the cylindrical support 1 and the annular partition 7 are arranged concentrically at an outer peripheral position of a cable connection portion 45 described later, and the internal liquid storage portion 40 is provided between the cylindrical support 1 and the cylindrical support 1. (Described below)
It is erected so that is formed.

Numeral 8 denotes a glass electrode, for example, a glass responsive film (sensitive part) 9 for pH measurement is provided at the lower end and a glass support tube 11 whose outer periphery except for the sensitive part 9 is covered with a resin body 10 is provided.
An internal electrode 12 made of AgCl and a KCl solution and a pH buffer solution 13 as an internal solution are sealed and configured.
Is connected via a platinum wire 15 to a plug 16 protruding above the resin body 10. And
When the glass electrode 8 thus configured is mounted in the concave portion 5, the plug 16 is electrically connected to a receptacle 18 formed on the lower end side of a connector 17 provided upright on the concave portion 5. is there. In addition, reference numeral 19 denotes a side wall provided upright on the concave portion 5, and reference numerals 20 to 22 denote sealing members.

Reference numeral 23 denotes a comparative electrode which is formed in a so-called double junction type in this embodiment. That is, reference numeral 24 denotes an internal space formed between the annular partition wall 7 and the side wall 25 erected inside the annular partition wall 7 above the concave portion 6, and an internal liquid junction made of porous plastic at the lower end thereof. A portion 26 is provided, and an internal electrode 27 made of AgCl is provided therein.
And a KCl solution 28 as an internal liquid, and an external liquid junction 29 made of porous ceramic
And a resin 31 and screwed into the recess 6 and formed below the internal liquid junction 26 to form the annular partition 7 and the cylindrical support 1.
The KCl solution 28 is formed so as to fill a communication space 32 that communicates with an internal liquid storage section 40 (described later). Reference numeral 33 denotes a rubber packing as a hermetic plug for closing the upper part of the internal space 24 with the upper end of the internal electrode 27 protruding.

Reference numeral 34 denotes a temperature sensor housed in a metal case 36 connected to the ground wire 35, and forms a sensor part 37 together with the sensitive part 9 of the glass electrode 8. 38 and 39 are lead wires connected to the temperature sensor 34.

Reference numeral 40 denotes an internal liquid storage portion formed between the cylindrical support 1 and the annular partition 7, and the lower end thereof communicates with the internal liquid junction 26 and the external liquid junction 29 via the communication space 32. The upper end communicates with an internal liquid inlet 41 formed at the upper end of the cylindrical support 1. The supply of KCl into the internal liquid storage section 40 is performed by a tube (not shown) connected to a KCl solution tank.
And through the internal liquid introducing section 41, and the internal liquid storing section 40
The KCl solution filled therein fills the communication space 32 and is further filled so that the liquid level E of the KCl solution 28 in the internal liquid storage section 40 is higher than the cable connection section 45 (described later). In the illustrated example, the internal liquid storage section 40 is extended above the cylindrical support 1 by ultrasonic welding of the cylindrical body 42 at the upper end of the annular partition wall 7, and 43 is cylindrical. Body 42 and cylinder 2
And a seal member interposed between the first and second members.

Reference numeral 44 denotes an extraction cable for transmitting a signal from the sensor unit 37 or the like to a measuring device main body (not shown), and includes five core wires 44a to 44e, and the core wire 44a is an upper end of the connector 17 of the glass electrode 8. The core wire 44b is connected to the upper end of the internal electrode 27 of the reference electrode 23, the core wires 44c and 44d are connected to the lead wires 38 and 39 of the temperature sensor 34, and the core wire 44e is connected to the ground wire 35. ing. In this embodiment, the connector 17 as a member for extracting a signal from the sensor unit 37,
A cable connection portion 45 which is a connection portion between the internal electrode 27, the lead wires 38, 39, etc. and the lead cable 44 is located in the annular partition wall 7. Reference numeral 46 denotes a seal member mounting groove which is recessed outside the cylindrical support 1.

2 (A), (B), and (C) show cross-sectional shapes along line AA, line BB, and line CC of FIG. 1 (A), respectively. That is, since the tubular body 2 of the tubular support 1 and the annular partition wall 7 are arranged concentrically, as shown in FIG. 40 can be formed annularly.

Thus, in the ion concentration measurement sensor having the above configuration, unlike the related art described at the beginning, a sensor portion 37 such as the sensitive portion 9 of the glass electrode 8 is formed at the lower end of the cylindrical support 1 and the sensor portion is formed. Above 37, an annular partition 7 is provided inside the cylindrical support 1 and a lower portion of the annular partition 7 is connected to an inner portion of the cylindrical support 1, so that a gasket having a plurality of through holes is provided. Can be eliminated. As a result, since a gasket having a plurality of through holes is not used, the sealing area can be significantly reduced, and thus the watertightness is improved.

The annular partition 7 is provided above the sensor section 37 to form a so-called double-pipe structure.
And a cable connecting portion 45 which is a connecting portion between the drawing cable 44 and a signal extracting member 17, 27, 38, 39, etc., and an inner portion formed between the annular partition wall 7 and the cylindrical support 1. Since the internal liquid 28 is filled in the liquid storing portion 40 so that the liquid level E is higher than the cable connecting portion 45, the members provided in the annular partition 7 including the cable connecting portion by the internal liquid 28 are electrically operated. Since the shield is electrically shielded, the measured value does not fluctuate even if the cylindrical support 1 is directly touched with the hand during measurement without being affected by disturbance.

In the above-described embodiment, the portion where the glass electrode 8 is provided does not have a double tube structure, but since this portion is a portion that is immersed in the liquid to be measured during measurement, There is no problem.

In the above embodiment, since the comparison electrode 23 is formed as a double junction type,
The KCl solution 28 in the sample 24 is not contaminated by the liquid to be measured, so that the measurement can be performed stably.

3 (A), 3 (B) and 3 (C) show another embodiment of the present invention. In this embodiment, the cylinders 2 and 3 are provided with flange portions 2a and 3a, respectively. In 3a, the cylindrical support 1 is formed by ultrasonic welding, and the ultrasonic wave is applied so that the lower end of the cylindrical portion 47 hanging from above the inside of the cylindrical body 2 is slightly inserted into the upper end of the annular partition wall 7. The sealing member 43 is interposed between the tubular portion 47 and the annular partition 7.

FIGS. 4 (A), (B) and (C) show still another embodiment of the present invention. In this embodiment, in the ion concentration measuring sensor shown in FIG. A screw hole 49 is provided so that a separate internal liquid introduction unit 50 can be screwed into the screw hole 49.

In FIGS. 3 and 4, the same reference numerals as those shown in FIG. 1 denote the same or corresponding components.

Needless to say, the embodiment shown in FIGS. 3 and 4 has the same effect as the embodiment shown in FIG.

Further, in each of the above-described embodiments, the comparison electrode 23 is formed as a double junction type, and the KC
l The solution is filled, but instead of this KCl solution, KCl
The solution may be filled with a gel-like internal liquid to which a polyacrylate-based polymer absorbent or a gelling agent such as agar or sodium carboxymethylcellulose is added. In this case, the internal electrode 27 melted
Ag ion diffusion is reduced to prevent clogging in the internal liquid junctions 26 and 29, and the internal space of the reference electrode 23 is reduced.
24 can prevent contamination.

The present invention can be applied not only to a sensor for measuring an ion concentration other than the above pH but also to any of an immersion type and a flow type.

〔The invention's effect〕

As described above, according to the ion concentration measurement sensor of the present invention, a sensor portion such as a sensitive portion of a glass electrode is formed at the lower end of the cylindrical support, and the cylindrical support is provided above the sensor portion. Since the annular partition is provided inside the body and the lower portion of the annular partition and the inner portion of the cylindrical support are connected, the sealing area can be significantly reduced without using a gasket having a plurality of through holes. Yes, and thus has a reliable watertightness. In addition, the internal liquid storage portion surrounded by the annular partition and the cylindrical support is formed in an annular shape at the outer peripheral position of the cable connection portion, and the internal liquid storage portion is positioned at the set position of the cable connection portion at the liquid level of the internal liquid. Since it is configured to be higher, it is possible to protect against disturbance such as electrostatic induction up to the space above the cable connection portion in the annular partition. Especially,
The entire outer periphery of the cable connection portion, which was conventionally unprotected against disturbance, is surrounded by the internal liquid, so that the effect of disturbance at this portion can be effectively prevented, and highly accurate ion concentration measurement can be performed.

[Brief description of the drawings]

1 and 2 show an embodiment of the present invention. FIGS. 1 (A) and 1 (B) are longitudinal sectional views, FIG. 1 (C) is a bottom view,
FIGS. 2 (A), (B) and (C) are each shown in FIG. 1 (A).
FIG. 3 is a diagram showing a cross-sectional shape taken along line AA, line BB, and line CC of FIG. 3 and 4 show another embodiment of the present invention. FIGS. 3 (A) and 3 (B) are longitudinal sectional views and FIG. 3 (C).
Is a bottom view, FIGS. 4A and 4B are longitudinal sectional views, and FIG. 4C is a bottom view. FIG. 5 shows a conventional example, wherein FIGS. 5A and 5B are longitudinal sectional views, and FIG. 5C is a sectional view taken along line CC in FIG. 5A. DESCRIPTION OF SYMBOLS 1 ... Cylindrical support, 7 ... Annular partition, 8 ... Glass electrode, 9 ... Sensitive part, 17, 27, 38, 39 ... Signal extraction member, 23 ... Reference electrode, 24 ... Internal space , 26… internal liquid junction, 28… internal liquid, 29… external liquid junction, 37… sensor part, 40… internal liquid storage part, 44… draw-out cable, 45…
... Cable connection.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuki Yoshioka 2nd Higashi-cho, Kichijoin-gu, Minami-ku, Kyoto, Kyoto Inside Horiba, Ltd. (56) References JP-A-62-298754 (JP, A)

Claims (3)

(57) [Claims] 1. An ion concentration measurement sensor having a sensor portion such as a sensitive portion of a glass electrode formed at a lower end portion of a cylindrical support, wherein an annular partition is provided inside the cylindrical support above the sensor portion. Connecting a lower portion of the annular partition and an inner portion of the cylindrical support, and providing a cable connection portion between a signal extraction member from the sensor unit and a cable drawn out to the outside in the annular partition; Between the partition wall and the cylindrical support, an internal liquid storage portion connected to the internal space of the reference electrode is formed, and the internal liquid storage portion is filled with the internal liquid so that the liquid level is higher than the cable connection portion, Further, the cylindrical support and the annular partition are concentrically arranged at an outer peripheral position of the cable connection portion. 2. An internal electrode and an internal liquid are provided in an internal space in which the reference electrode is formed in the annular partition and has an internal liquid junction at a lower end, and an external liquid junction is provided in the internal liquid storage. The ion concentration measurement sensor according to claim 1, wherein a part is formed, and further, the inside of the internal space and the inside of the internal liquid storage part are connected via the internal liquid junction part. 3. An ion concentration measuring sensor according to claim 2, wherein a gel-like internal liquid is provided in said internal space.