TW202317980A - Sensor of pH meter and its reference electrode including a reference electrode suitable for contacting the object under test and a glass electrode inserted in the reference electrode - Google Patents

Abstract

A sensor of pH meter is suitable for detecting a test object, and includes a reference electrode suitable for contacting the object under test and a glass electrode inserted in the reference electrode. The reference electrode includes a housing unit having a hollow tubular casing, and at least one conducting unit filled in the housing unit. The at least one conducting unit has a porous abutment member suitable for contacting the test object, and a conduction member tightly filled on one side of the abutment member and cooperating with the abutment member to define an interface. The conduction member is made by soaking the superabsorbent polymer in the potassium chloride solution. The glass electrode is inserted in the conduction member of the at least one conduction unit of the reference electrode. The glass electrode protrudes from the abutment member of the at least one conducting unit of the reference electrode toward the test object.

Description

pH meter sensor and its reference electrode

The invention relates to a detection instrument, in particular to a pH meter sensor and its reference electrode.

The pH meter sensor mainly includes a glass electrode, a reference electrode, and a temperature compensation electrode. The potassium chloride currently used in the reference electrode includes liquid potassium chloride made from a saturated potassium chloride solution, and a wooden block Solid potassium chloride and other types made by soaking in saturated potassium chloride solution. However, the liquid potassium chloride is easy to seep out, or the silver/silver chloride sensing element is invalid due to the ion pollution of the analyte, resulting in a short service life; and the solid potassium chloride has to overcome the shell and the wooden block The tolerance between them, the difficulty of manufacture and the high cost of time, that is, all forms of reference electrodes have their disadvantages. Since the design of the reference electrode is related to the manufacturing cost, service life, and related performance of the pH meter sensor, it is still necessary to find a solution.

Therefore, the object of the present invention is to provide a reference electrode of a pH meter sensor that is simple to manufacture and assemble and has a long service life.

Therefore, the reference electrode of the pH meter sensor of the present invention is suitable for contacting an object to be measured, and includes a housing unit including a hollow tubular shell, and at least one conduction unit filled in the housing unit. The at least one conduction unit includes a porous junction piece suitable for contacting the object to be tested, and a junction piece tightly fitted to fill one side of the junction piece and cooperate with the junction piece to define an interface. The conducting member is made by immersing the polymer absorber in potassium chloride solution.

Another object of the present invention is to provide a sensor for a pH meter that is simple to manufacture and assemble and has a long service life.

Therefore, the pH meter sensor of the present invention includes a reference electrode as mentioned above, and at least one of the conducting members inserted in the reference electrode, and connected from one of the connecting members of the reference electrode A glass electrode protruding toward the object to be measured.

The effect of the present invention lies in: making the conduction member of the at least one conduction unit with a polymer absorber, that is, after directly filling a sufficient amount of polymer absorber into the containing unit, the polymer absorber has elasticity and The soft material properties enable the at least one conducting member to close the gap between the shell and the glass electrode, so as to ensure closeness and reduce tolerance problems during manufacturing and assembly, effectively improving the assembly yield of the present invention and reducing Labor and material costs are reduced, and the service life can be extended by the high water retention of the polymer absorber.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are denoted by the same numerals.

Referring to Fig. 1, a first embodiment of the pH meter sensor of the present invention is suitable for detecting an analyte (not shown), and includes a reference electrode 1 suitable for contacting the analyte, and an insertion The reference electrode 1 is also suitable for the glass electrode 2 contacting the object to be tested. In the first embodiment, the analyte is in a liquid state.

The reference electrode 1 includes a containing unit 11 , two conductive units 12 filled in the containing unit 11 and connected to each other, and a sensing element 13 extending outward from one of the conductive units 12 . The housing unit 11 has a hollow tubular shell 111, a hollow tubular inner tube 112 accommodated in the shell 111, and a seal on the side of the shell 111 opposite to the object to be tested. Cover 113. The inner tube 112 has a support portion 114 extending in the same direction as the outer shell 111, and a protruding radially outward from the support portion 114 toward the side of the object to be tested, and is pressed against the inner side of the outer shell 111. Department 115.

Each conduction unit 12 has a junction piece 121 which is porous and is suitable for contacting the object to be tested, and a conduction piece 122 tightly fitted to fill one side of the junction piece 121, the junction piece 121 and An interface 120 is formed at the contact of the via 122 . In the first embodiment, the connecting elements 121 and the conducting elements 122 are alternately arranged sequentially, and the conducting elements 122 are not in contact, so that the first embodiment forms two interfaces 120 .

In this first embodiment, the junction members 121 are porous structures formed with multiple channels for ions to pass through, usually made of Teflon (Teflon) and potassium chloride co-sintered, with enough Excellent acid and alkali resistance, and can be applied to the analytes with different acid and alkali degrees. However, in other implementations of the first embodiment, the types of the interface elements 121 are not limited thereto, as long as a porous structure can be formed to reliably introduce the analyte as a liquid. The vias 122 are made by soaking superabsorbent polymers (SAP) in potassium chloride solution, and the polymer absorber is preferably polyacrylate (Polyacrylate) or polyacrylamide (polyacrylamide) ). Among them, it is preferable to place the powdery polymer absorber into a saturated potassium chloride solution, and the polymer absorber will swell into a jelly-like elastic body due to the absorption of potassium chloride solution, preferably The fabrication of the vias 122 is completed when the polymer absorber absorbs to saturation and no longer expands in volume.

In addition, in the first embodiment, the inner tube 112 can support the inside of the shell 111 with the engaging portion 115 , and use the support portion 114 to cooperate with the shell 111 and the glass electrode 2 to support the conducting elements. 122 , which can improve the overall structural strength of the first embodiment, so as to prevent the conductive elements 122 from being extruded or deformed due to external force. The cover 113 can close one end of the housing 111 and delay the evaporation of water contained in the conductive elements 122 to prolong the service life of the first embodiment. The inductive element 13 is a silver/silver chloride (Ag/AgCl) wire, which can output potential to the outside. However, in other implementations of the first embodiment, the type of the inductive element 13 is not limited to this , as long as the electrical conductivity can be ensured and the potential information can be output.

For ease of description, the interface 120 positioned below is marked as 120a in FIG. 1 , and the interface 120 positioned above is marked as 120b; The connecting element 121 is marked as 121b; in addition, the conducting element 122 on the inside is marked as 122a, and the conducting element 122 on the outside is marked as 122b.

In the first embodiment, the interface member 121a is clamped on the side of the inner tube 112 of the containing unit 11 facing the object to be tested, and the conducting member 122a is filled on the interface member 121a and the inner tube. 112, and cooperate with the interface member 121a to define the interface 120a. And the junction piece 121b is stacked on the conduction piece 122a, and the conduction piece 122b is filled between the inner tube 112 and the housing 111 of the housing unit 11, and contacts the junction piece 121b, and connects with the junction The part 121b cooperates to define the interface 120b, and one end of the sensing part 13 is inserted into the conducting part 122b.

The glass electrode 2 is inserted into the conducting member 122a of the reference electrode 1, and protrudes from the connecting member 121a of the reference electrode 1 to the object under test, so as to be able to contact the object under test when using the first embodiment . In the first embodiment, the glass electrode 2 also has a temperature compensation function. However, since the design of the aforementioned functions is well known to those skilled in the art, it will not be repeated here.

Since the conducting members 122 are made of an elastic and soft polymer absorber, when making the first embodiment, it is not necessary to make the conducting members 122 into a predetermined size in advance, and only need to directly place a sufficient amount The polymer absorber is filled into the housing unit 11, and the conductive parts 122 can close the gaps with the outer shell 111, the inner tube 112, and the glass electrode 2 by their own elasticity, so that the conductive parts 122 can be guaranteed 122, the outer shell 111, the inner tube 112, and the glass electrode 2, and reduce the tolerance problem of the lead-throughs 122 during manufacture and assembly, effectively improving the assembly quality of the first embodiment. Efficiency and lower material costs, and can also reduce labor costs through the convenience of assembly.

When the first embodiment is actually used, and the junction piece 121a of the reference electrode 1 and the glass electrode 2 are immersed in the liquid object to be tested, the negative ions and Water molecules can reach the interface 120a through the porous junction member 121a. Then, since there is no gap between the conductive elements 122 and the outer shell 111, the inner tube 112, and the glass electrode 2, the anions can pass through, and the conductive elements 122 are in a saturated state that neither absorbs anions nor allows anions to pass through. , so the negative ions will be blocked by the conducting member 122a and remain in the interface 120a. Even if there is a gap between the conducting member 122a and the shell 111, the inner tube 112, or the glass electrode 2 due to an assembly error, the conducting member 122b can prevent the negative ions from contacting the sensing member 13, so that the negative ions stay in the sensing member 13. interface 120b. By setting up the interfaces 120 and the conductive elements 122 as two lines of defense, the inductive element 13 is prevented from becoming invalid due to contamination, so the service life of the first embodiment can indeed be extended.

However, since the vias 122 are in a saturated state that no longer absorbs water molecules, the water molecules will continue to pass through the interface 120a, the vias 122a, the junction 121b, the interface 120b, and the vias 122b in sequence, And the reference electrode 1 can provide a stable reference potential. In addition, the polymer absorber has high hydrophilicity and high water retention, and is insoluble in water, so that the conductive elements 122 can retain a sufficient amount of water for a long time without drying up, and can be maintained in a solid state with elasticity, so it can extend the operating life. The service life and shelf life of the first embodiment.

Furthermore, since the polymer absorber is electrically neutral and has high absorption, and the conductive members 122 no longer absorb other ions, compared with the prior art, the wooden block has poor absorption. For solid potassium chloride with low potassium chloride content, or liquid potassium chloride that is easily permeated by other ions, the lead-throughs 122 will contain potassium chloride with a large amount and high purity, so that the lead-throughs 122 The impedance of 122 is low and the conduction speed is fast, so the first embodiment is not easily affected by other ions, the error generated during measurement is low, and the response speed is fast.

It should be added that the measurement principle of the glass electrode 2 of the first embodiment is the same as that of a general pH meter sensor, and since the measurement principle of the glass electrode 2 is well known to those skilled in the art, Therefore, I will not repeat them here. In addition, the number of the conduction units 12 is not limited to two, and the reference electrode 1 can also include only one conduction unit 12, although the reduction in the number of the conduction units 12 will slightly weaken the barrier to negative ions from entering the site. The efficiency of the first embodiment, but substantially the same effect of blocking anions in the analyte and outputting a stable reference potential can be achieved.

Referring to Fig. 2, the reference electrode 1 of a second embodiment of the pH meter sensor of the present invention, this second embodiment is substantially the same as the first embodiment, the difference lies in the conduction units 12 of the reference electrode 1 Arrangement, it must be explained first that the installation method of the glass electrode 2 (see Figure 1) of the second embodiment is the same as that of the first embodiment, in order to clearly illustrate the arrangement of the conduction units 12, shown in Figure 2 The glass electrode 2 is omitted from illustration. In the second embodiment, the conducting member 122a is directly stacked on the connecting member 121a, and the conducting member 122b is directly stacked on the connecting member 121b, and the two interfaces 120 can also be formed, And the service life of the sensing element 13 is extended by the cooperation of the conducting elements 122a and 122b to block the negative ions in the analyte.

To sum up, the pH meter sensor and its reference electrode of the present invention make the conductive members 122 of the reference electrode 1 with a polymer absorber, so that the elastic and soft conductive members 122 can be closed and connected to the The gap between the shell 111 and the glass electrode 2 is to ensure the tightness and reduce the tolerance problem generated during the manufacturing assembly, effectively improve the assembly yield of the present invention and reduce the cost of manpower and materials, and can be used by the polymer absorber The high water retention, and cooperate with the inner tube 112 to strengthen the overall structure and prolong the service life, so the purpose of the present invention can be really achieved.

But what is described above is only an embodiment of the present invention, and should not limit the scope of the present invention. All simple equivalent changes and modifications made according to the patent scope of the present invention and the content of the patent specification are still within the scope of the present invention. Within the scope covered by the patent of the present invention.

1: Reference electrode 11: Containment unit 111: Shell 112: inner tube 113: capping 114: support part 115: engaging part 12: Conduction unit 120, 120a, 120b: interface 121, 121a, 121b: junction pieces 122, 122a, 122b: Conductors 13: Sensing parts 2: Glass electrode

Other features and effects of the present invention will be clearly presented in the implementation manner with reference to the drawings, wherein: Figure 1 is a schematic side view in cross-section illustrating a first embodiment of a pH meter sensor of the present invention; and FIG. 2 is a schematic cross-sectional side view illustrating two conductive units and a sensing element of a reference electrode of a second embodiment of the pH meter sensor of the present invention.

1: Reference electrode

11: Containment unit

111: shell

112: inner tube

113: capping

114: support part

115: engaging part

12: Conduction unit

120, 120a, 120b: interface

121, 121a, 121b: junction pieces

122, 122a, 122b: Conductors

13: Sensing parts

2: Glass electrode

Claims (10)

A reference electrode for a pH meter sensor adapted to contact an object to be measured, comprising: A containment unit comprising a hollow tubular casing; and At least one conduction unit is filled in the containing unit, and includes a porous junction piece suitable for contacting the object to be tested, and a tight fit filled side of the junction piece and connected to the junction piece. The interface part cooperates to define an interface conducting part, and the conducting part is made by immersing the polymer absorber in potassium chloride solution. The reference electrode of the pH meter sensor as claimed in Claim 1 comprises two conducting units connected to each other, the connecting elements and the conducting elements are alternately arranged sequentially, and the conducting elements are not in contact. The reference electrode of the pH meter sensor according to claim 1, wherein the containing unit further includes an inner tube in the shape of a hollow tube and accommodated in the outer casing. The reference electrode of the pH meter sensor according to claim 3 comprises two conducting units connected to each other, the junction elements and the conducting elements are arranged alternately in sequence, and the conducting elements are not in contact. The reference electrode of the pH meter sensor as described in claim item 4, wherein one of the junctions is clamped on the side of the inner tube facing the object to be tested, and one of the conductive members is filled in one of the junctions On the interface member and inside the inner tube, another interface member is stacked on one of the conducting members, and the other conducting member is filled between the inner tube and the outer shell, and contacts the other interface member. The reference electrode of the pH meter sensor according to claim 5 further includes an inductive element whose one end is inserted into the other conducting element. The reference electrode of the pH meter sensor as claimed in claim 3, wherein the inner tube has a support part extending in the same direction as the outer shell, and a side radially facing the object to be measured from the support part The outside protrudes and abuts against the fastening part inside the shell. The reference electrode of the pH meter sensor as claimed in item 1, wherein the containing unit further includes a cover that is blocked on the side of the housing opposite to the object to be measured. The reference electrode of the pH meter sensor as claimed in item 1, wherein the polymer absorber of the conducting member is polyacrylate or polyacrylamide. A pH meter sensor is suitable for detecting an object to be tested, and includes: A reference electrode as described in any one of claims 1 to 9, suitable for contacting the analyte; and A glass electrode is inserted in the conducting member of at least one of the conduction units of the reference electrode, and protrudes from the junction member of one of the conduction units of the reference electrode toward the object under test.

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