US-12618797-B2 - Electrolyte measuring structure, flow-type ion-selective electrode using the same, and electrolyte measuring device

US12618797B2US 12618797 B2US12618797 B2US 12618797B2US-12618797-B2

Abstract

An electrolyte measuring structure includes a housing and a sealing material. The electrolyte measuring structure being connectable to another electrolyte measuring structure via the sealing material. The housing includes a main body having a flow path therethrough and a fixing structure. The fixing structure includes a first protrusion having a first hole, a second protrusion, and a fixing recess. The sealing material includes a front surface and a back surface. The sheet region has a second hole. In a state where the sealing material is fixed, a first protrusion amount is larger than a second protrusion amount. When viewed in a cross-section passing through a central axis of the second hole in a state where the sealing material is removed from the fixing structure, a first slope defined below is smaller than a second slope.

Inventors

Ichiro Yamakawa
Kie ORIHASHI
Hiroki Nakatsuchi
Isamu Yoshida
Masafumi Miyake

Assignees

HITACHI HIGH-TECH CORPORATION

Dates

Publication Date: 20260505
Application Date: 20220615
Priority Date: 20210806

Claims (9)

1 . An electrolyte measuring structure comprising a housing and a sealing material, and being connectable to another electrolyte measuring structure via the sealing material, wherein the housing includes a main body having a flow path therethrough and a fixing structure for fixing the sealing material to the main body, wherein the fixing structure includes a first protrusion having a first hole connected to the flow path, a second protrusion formed on an outer periphery of the first protrusion, and a fixing recess for detachably fixing the sealing material formed by the first protrusion and the second protrusion, wherein the sealing material includes a front surface designed to be in contact with the other electrolyte measuring structure, and a back surface designed to be in contact with the fixing structure, and is an elastic body in which a sheet region that is a sheet-like region, and a protrusion region provided on an outer peripheral side surface of the sheet region and embedded in the fixing recess are integrally molded, wherein the sheet region has a second hole arranged at a position corresponding to the first hole in a state where the sealing material is fixed to the fixing structure, and wherein in a state where the sealing material is fixed to the fixing structure and is not in contact with the other electrolyte measuring structure, a first protrusion amount defined below is larger than a second protrusion amount: the first protrusion amount protrudes from a front surface of the sheet region, and the second protrusion amount protrudes from a front surface of the protrusion region, and when viewed in a cross-section passing through a central axis of the second hole in a state where the sealing material is removed from the fixing structure: (i) a first slope defined below is smaller than a second slope: (ii) the first slope is an average slope of the front surface of the sheet region, and (iii) the second slope is an average slope of the front surface of the protrusion region.
2 . The electrolyte measuring structure according to claim 1 , wherein the protrusion region of the sealing material is sandwiched between respective side surfaces of the first protrusion and the second protrusion forming the fixing recess, and is pressed and fixed.
3 . The electrolyte measuring structure according to claim 1 , wherein based on the second hole, a protrusion amount of a portion farther than the first portion of the sheet region is smaller than the protrusion amount of the first portion.
4 . The electrolyte measuring structure according to claim 1 , wherein the first portion is a portion adjacent to the second hole.
5 . The electrolyte measuring structure according to claim 4 , wherein an inner surface of the sealing material forming the second hole projects in a direction of a center of the second hole.
6 . The electrolyte measuring structure according to claim 4 , wherein a thickness of the first portion is larger than an average thickness of a connection portion between the sheet region and the protrusion region.
7 . The electrolyte measuring structure according to claim 4 , wherein in a state where the sealing material is removed from the fixing structure, in the sheet region, the average thickness and the average protrusion amount are gradually reduced from the first portion to the protrusion region.
8 . A flow-type ion-selective electrode comprising the electrolyte measuring structure according to claim 1 .
9 . An electrolyte measuring device comprising the electrolyte measuring structure according to claim 1 .

Description

TECHNICAL FIELD The present invention relates to an electrolyte measuring structure for measuring electrolyte concentration in a solution, a flow-type ion-selective electrode having the electrolyte measuring structure, and an electrolyte measuring device. BACKGROUND ART The ion-selective electrode is a device that can quantify the concentration of ions to be measured in a sample solution by measuring the potential difference between the electromotive force generated in an electrode of a detection unit when the sample solution is brought into contact with the detection unit, and the reference electrode. Among the ion-selective electrodes, the flow-type ion-selective electrode has a built-in flow path through which the sample solution flows, and the detection unit is provided in the flow path. Therefore, by changing the sample solution flowing in the flow path, the concentration of the ion to be measured can be continuously measured. Further, by connecting a plurality of the flow-type ion-selective electrodes having different ions to be measured, or by providing a plurality of the detection units for measuring different ions in the flow path in the electrode, it is possible to measure the concentration of each ion simultaneously for different ion species. Due to such advantages, the flow-type ion-selective electrodes are used for clinical testing in the medical field, and are installed as electrolyte concentration measuring units not only in dedicated machines for measuring electrolyte concentration, but also in biochemical automatic analyzers. Since the ion-selective electrode in the electrolyte concentration measuring unit is generally a consumable item and has a lifespan of, for example, two to three months, the ion-selective electrode needs to be replaced with a new one every time a predetermined period of time elapses. As a method for attaching the ion-selective electrode to the electrolyte concentration measuring unit, as disclosed in PTL 1, a method for stacking a plurality of ion-selective electrodes and using an O-ring on the connection portion between the respective flow paths is well known. FIG. 15 is a schematic diagram illustrating an example of a related art structure of a flow path connection unit of an ion-selective electrode disclosed in PTL 1. The ion-selective electrode includes a flow path 1502 that penetrates a main body 1501 that forms a housing, and a connection structure is formed in a convex shape at one end of the flow path 1502. This connection structure is configured such that an O-ring 1508, which is a sealing material, is held in a fixing structure in which a concave portion 1510 is formed for fixing the sealing material. This connection structure can be fitted to a flow path connection unit 1507 provided in another ion-selective electrode 1591 to connect a plurality of ion-selective electrode flow paths. In FIG. 15, two connected flow paths are illustrated as one body for convenience. Since the flow path 1502 and the O-ring 1508 are usually arranged at a certain distance, a gap 1531 is generated between the ion-selective electrodes. A part of the sample solution flowing through the flow path 1502 flows into the gap 1531 and is retained therein. When a plurality of samples are measured in sequence, the retained sample solution is gradually released into the flow path when the sample solution for the next measurement flows in. In the case of such a structure, the retained sample solution is mixed with a sample solution to be originally measured, which may affect the measurement result. That is, when an amount of sample solution is large, there is little possibility of affecting the measurement result, but when the amount of sample solution is little, there is a possibility of affecting the measurement result and hindering accurate measurement. In addition, the electrolyte concentration measuring unit consumes a small amount of the reagent per sample, but this consumption increases when the electrolyte concentration measuring unit operates continuously, and it is necessary to replace reagent bottles several times a day. Since replacing the reagent bottles leads to a decrease in the throughput of sample measurement due to re-start-up, there is a strong demand from users to reduce replacement work. When the amount of reagent solution is reduced, the ratio of a remaining liquid increases, so that the influence on the measured value increases. As a technique for solving such problems, a technique for reducing the remaining liquid by using a sealing material having a flat sheet portion and a protrusion portion including a convex portion fixed to a concave portion of the ion-selective electrode to reduce the gap between the flow path and the sealing material, is disclosed in PTL 2. FIG. 16 is a schematic diagram illustrating an example of a related art structure of a flow path connection unit of an ion-selective electrode disclosed in PTL 2. The ion-selective electrode includes a flow pa