JPH0131961Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a technology for improving solid membrane electrodes for biological fluids used for measuring components of biological fluids.

First, an example of a conventional solid membrane electrode for biological fluids is shown in the third section.
As shown in the figure. This solid membrane electrode for biological fluid has a response member 22 to which a lead wire 21 for signal extraction is connected.
A resin adhesive is applied to the outer peripheral surface of the cylindrical electrode body 23 and the inner surface of the tip of the cylindrical electrode body 23, and
1 is inserted into the internal space of the electrode body 23, the response member 22 is disposed in contact with the inside of the tip of the electrode body 23 to join both 22 and 23, and the liquid contact side of the response member 22 is The surface portion is covered with a semipermeable membrane 24 fixed to the outer peripheral surface portion of the electrode body 23.

In such an electrode, the gap between the contact surfaces of the electrode body 23 and the response member 22 is small and the insulating layer made of resin adhesive is extremely thin, and when air bubbles are generated in the applied resin adhesive, However, since the air bubbles lead to uneven coating of the resin adhesive, there is a drawback that poor insulation with respect to the lead wire 21 is likely to occur.

Particularly, since the object to be measured by the electrode is a very small amount of biological fluid, and the electrode itself is formed in a minute size, it is easy to cause poor adhesion and even poor insulation.

In addition, since the surface of the response member 22 on the liquid contact side is flat, the semipermeable membrane 2 for removing interference components
4 in close contact with the entire surface of the liquid-contacting side surface of the response member 22, and the contact pressure is weaker toward the center of the contact surface. There were problems in that it was easy to create a dead space and the response speed was low.

The object of the present invention is to provide a solid membrane electrode for biological fluids that eliminates the above-mentioned disadvantages at once through rational improvement techniques.

Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a solid membrane electrode 1 for biological fluids, and FIG. 2 shows its main parts.

In the figure, reference numeral 2 denotes a cylindrical synthetic resin electrode body having a space 3 inside, and a large diameter recess 2a slightly larger than the inner diameter of the space 3 at its tip.
A small diameter cylindrical portion 2b is formed which is slightly smaller than the outer diameter of the electrode body itself.

Reference numeral 4 denotes a substantially cylindrical response member made of, for example, Ag/Agcl, and a lead wire (for example, a silver wire) 7 for signal extraction is connected to one end surface of the member through a terminal plate 6 made of silver. is inserted into the internal space 3 of the electrode body 2, and the response member 4 is placed in contact with the large diameter recess 2a of the electrode body 2. 8 is a connector pin connected to the other end side of the lead wire 7.

Next, 5 is a fitting hole 5a for the response member 4.
This is a retaining ring with a flange formed therein, which is arranged to fit into the small-diameter cylindrical portion 2b of the electrode body 2, and which is arranged so that the inner surface of the retaining ring 5, the tip of the electrode body 2, and the outer periphery of the response member 4 are connected to each other. The three surface portions form an annular space 9 that communicates with the gap between the contact surfaces of the electrode body 2 and the response member 4.

This space 9 and the inside of the space 3 of the electrode body 2, and the large diameter recess 2a and the response member 4
The gap between the abutting surfaces of A highly water-repellent silicone resin adhesive 10 is filled, and the electrode body 2, the response member 4 and the retaining ring 5 are
, and insulation between the lead wire 7 and the outside of the electrode.

In addition, the liquid-contact side surface of the response member 4 and the retaining ring 5 on the outer periphery thereof are formed into a series of spherical parts having the same spherical core and the same diameter, and a semipermeable membrane is attached to this spherical part. (It is for removing interfering components in biological fluids, and for example, a polypropylene membrane coated with cellulose acetate is used.) 11 is covered and a ring 12 is fitted, and the ring 12 and the retaining ring are fitted together. 5 and sandwich the peripheral edge of the semipermeable membrane 11.

13 is a socket, 14 is an O-ring, and 15 is a packing.

As explained above, the solid membrane electrode for biological fluids according to the present invention has a lead wire connected to a substantially cylindrical response member inserted through a cylindrical electrode body.
The response member is arranged in contact with the tip of the electrode body, and a retaining ring is installed on the outer peripheral surface of the response member in correspondence with the tip of the electrode body, and the retaining ring and the electrode body are arranged in contact with each other. An annular space communicating with the gap between the contact surfaces of the electrode body and the response member is formed between the tip end of the electrode body and the outer peripheral surface of the response member, and the space is filled with a resin adhesive. The above three parts are joined together, and the liquid-contact side surface of the response member and the stop ring on its outer circumference are formed into a series of spherical parts, and the spherical part is fixed to the outer circumference of the stop ring. It is characterized by being covered with a permeable membrane.

That is, an annular space communicating with the gap between the contact surfaces of the electrode body and the response member is formed between the retaining ring, the tip of the electrode body, and the outer peripheral surface of the response member, and this space is filled with resin. By filling the adhesive, the thickness of the insulating layer of the resin adhesive on the lead wire becomes extremely large, resulting in insufficient resin adhesion in the gap between the contact surfaces of the electrode body and the response member. Even if it is, insulation with respect to the lead wire can be ensured, and this structure is particularly advantageous in constructing a minute electrode for biological fluids.

In addition, by making the liquid-contact side surface of the response member and the retaining ring on its outer periphery a spherical surface, the semipermeable membrane has extremely high adhesion to the entire surface of the surface.
In addition, the contact pressure becomes approximately equal, and since no dead space is created between the semipermeable membrane and the response member, the response speed becomes faster. Overall, this is an extremely simple and rational improvement. This made it possible to eliminate all of the conventional inconveniences in one fell swoop.

[Brief explanation of the drawing]

FIG. 1 is an overall front view of a solid membrane electrode for biological fluid with the main part cut away, and FIG. 2 is an enlarged sectional view of the main part. FIG. 3 is an enlarged sectional view of the main parts of a conventional solid membrane electrode for biological fluids. 2... Electrode body, 4... Response member, 5... Stop ring, 7... Lead wire, 9... Annular space, 10
... Resin adhesive, 11 ... Semipermeable membrane.

Claims (1)

[Scope of utility model registration request] With the lead wire connected to the approximately cylindrical response member inserted through the cylindrical electrode body, the response member is placed in contact with the tip of the electrode body, and the response member is placed in contact with the tip of the electrode body. Correspondingly, a retaining ring is installed on the outer peripheral surface of the response member, and
An annular space communicating with the gap between the contact surfaces of the electrode body and the response member is formed between the retaining ring, the tip of the electrode body, and the outer peripheral surface of the response member, and an annular space is formed in the space. The above three parts are joined together by filling with a resin adhesive, and furthermore, the liquid-contact side surface of the response member and the retaining ring on its outer periphery are formed into a series of spherical parts, and the spherical part is connected to the retaining ring. A solid membrane electrode for biological fluids, characterized in that it is covered with a semipermeable membrane fixed to the outer peripheral surface.