JPS5927860B2 - Composite electrode for measuring PH etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite electrode for measuring ions, ORP, pH, etc.

The ion concentration of the liquid, ORP, etc. is determined by the so-called electrode method.
Measuring pH and the like requires a measuring electrode (for example, a glass electrode in the case of pH) and a reference electrode, but composite electrodes that integrate the two are now widely used because they are convenient to use. Conventionally, such composite electrodes were developed in Japanese Patent Application Laid-open No. 5
There are those shown in Japanese Patent Application Laid-open No. 1-41590 and Japanese Patent Application Laid-Open No. 51-98089. These devices are configured so that the storage member housing the reference electrode and temperature sensor can be inserted and removed from the center body, and a liquid junction holding portion is provided between the storage member and the flange at the bottom of the center port. . The reason why the central body and the storage member can be freely inserted and removed is to facilitate the exchange of the liquid junction holding part and the exchange of the internal liquid filled in the space between the liquid junction holding part and the central body. however,
This conventional structure has the following drawbacks.

1 Since the central body and the storage member are removable, there is a risk that the internal fluid may reach the upper lead pin through the sliding contact area between the central body and the storage member. The ring must be fitted and sealed.

However, when an O-ring is fitted, the O-ring groove has a notch effect, which causes stress concentration and deteriorates mechanical strength.In addition, when replacing the internal fluid, only a portion of the O-ring achieves a sealing effect and is not completely sealed. The disadvantage is that a good sealing effect cannot be expected. That is, to replace the internal fluid, it is necessary to pull out the central body a predetermined length from the storage member, but when doing so, some O-rings come off the sliding contact area between the central body and the storage member and are exposed, causing the internal fluid to May come into contact.
For this reason, during and after exchanging the internal liquid, only the O-rings other than the O-rings that have come into contact with the internal liquid have a sealing effect, and a perfect sealing effect cannot be expected. Since the two-liquid retainer is located between the central body and the lower flange of the housing member, the central body must be completely removed from the housing member in order to replace the fluid junction retainer.

Therefore, at that time, all the O-rings come into contact with the internal liquid, which may impair the sealing effect of all the O-rings, and the replacement work is troublesome.
3. Since the central body and the storage member are separate bodies, there are a large number of parts, which makes component management troublesome, and it is necessary to tightly connect the central body and the storage member in order to maintain the above-mentioned sealing effect. However, there are disadvantages in that machining accuracy is required for the sliding contact portion between the two, making machining difficult and increasing manufacturing costs.

The present invention provides a useful composite electrode for measuring PH etc. which eliminates such drawbacks one by one.

Examples will be explained below. FIG. 1 is a view of the central axis body of a composite electrode according to an embodiment of the present invention, viewed from the edge of the substrate, and FIG. 2 is a cross-sectional view taken along line A-A shown in FIG. 1. FIG. 3 shows a first embodiment of a composite electrode according to the present invention.
It is a sectional view taken along the same plane as the AA cross section shown in the figure. In Figures 1 and 2, reference numeral 1 denotes a central shaft body integrally molded from plastic, which has a measuring chip lead pin storage space 2 formed with an open upper end and an open lower end that communicates with the space. a measurement chip storage space 6, a packing storage space 3 for fixing the reference electrode internal electrode lead wire, and a thermistor storage space 5, which are located outside the measurement chip lead pin storage space 2 and are formed with an open upper end.
, a passage 4 for inserting the lead wire of the inner electrode of the reference electrode, which penetrates from the lower part of the packing storage space 3 to the lower central side wall, and a threaded portion 8 formed on the outer circumferential wall at the lower end of the measurement chip storage space 6. have.

7 is a male screw part for fixing the liquid holding part.

Next, explanation will be given according to FIG.

Reference numeral 1 denotes a central shaft body, and reference numeral 9 denotes a cylindrical liquid junction holding part made of synthetic resin such as polytetrafluoroethylene and having a liquid junction part 10 .

The liquid junction holding part 9 has a male screw part 11 provided on the upper inner wall thereof.
It is removably provided on the outside of the center shaft body 1 by screwing it into the male threaded portion 7 of the center shaft body 1 . Reference numeral 12 denotes a gasket provided between the lower end of the liquid junction holding portion 9 and the center shaft body 1, which serves to prevent internal liquid from leaking and also serves to fix the liquid junction holding portion 9 to the center shaft body 1.

13 is an O-ring, and 14 is a presser foot.

This packing holder 14 is screwed onto the threaded portion 8 of the center shaft body 1, and functions to press the packing 12 between the lower end of the liquid junction holding portion 9 and the center shaft body 1. 15 is a titanium ring for protecting the liquid junction holding portion.

A liquid junction portion 1 is provided between the center shaft body 1 and the liquid junction holding portion 9.
A space 16 is formed which is connected to the outside only by 0, is filled with the internal liquid of the comparison electrode, and houses the internal electrode 17 of the comparison electrode. The inner pole 17 is connected to a comparison electrode lead pin 20 via a lead wire 18 inserted into the insertion passage 4 and a printed board 19. 21 is a packing for fixing the lead wire 18.

A thermistor 22 is housed in the space 5 of the central shaft body 1, and is connected to a thermistor lead pin 23 via a printed board 19, and to a cap 25 made of metal such as titanium via an earth spring 24.

26 is a pin guide, and the lead pins 20 and 23 are fixed by a snap or adhesive.

Reference numeral 27 denotes a metal earth pipe made of titanium or the like, which is attached to the metal cap 25 and fixed to the central shaft body 1 via a mounting ring 28 and an O-ring 29.

30 is a measurement chip, and various measurement electrodes are used depending on the object to be measured, such as ions, 0RP1pH, etc.

The measuring chip 30 is connected to the lead pin 32 by fitting a pin 31 provided at the end of the measuring chip 30 into a recess 33 provided at the lower end of the measuring chip lead pin 32. Also, the lower part of the measuring chip 30 is a packing 3.
4 is fixed to the center shaft body 1, and the packing 34 is fixed with a protective cowl up 35. In order to replace the liquid junction, remove the protective cap 35 and packing holder 14 from the threaded part 8, pull out the liquid junction holding part 9 downward, and then insert the new liquid junction holding part 9 in the opposite direction to the above. After inserting and fixing it in the procedure described above, and filling the internal liquid, the packing 12 is tightened and fixed with the packing presser 14, and the protective cap 35 is tightened and fixed. In addition, when replenishing only the internal liquid, loosen the protective cap 35 as necessary, then loosen the packing presser foot 14, shift the packing 12, and remove the liquid junction holding part 9.
The internal liquid is replenished from the gap created between the packing 12 and the packing 12, and the packing presser foot 14 and the protective cap 35 are tightened and fixed. Since the present invention has the above-described configuration, it has the following effects.

1. A liquid junction holding part 9 is detachably provided on the outside of the center shaft body 1, and a packing 12 is provided between the lower end of the liquid junction holding part and the center shaft body, and this packing 12 is screwed into the threaded part 8 at the lower end of the center shaft body. Since the structure is such that it is held down by a sealing holder 14, the internal liquid and the liquid junction can be replaced by simply loosening the sealing holder or by removing it from the threaded part 8 and pulling out the liquid junction holding part downward. I can do it.

For this reason, the internal liquid and liquid junction can be replaced without having to shift or pull out the center body from the storage member as in the past, which greatly simplifies the replacement work, and when replacing the center body, There is no need to worry about the lead pin at the top of the body coming into contact with the internal fluid. 2 In addition, since the internal fluid etc. can be replaced by simply removing the gasket by loosening the gasket retainer, there is no need to separate the central body and the storage member, and the central shaft that integrates them As a result of being able to adopt the body, the number of parts is reduced and there is no need to consider sealing effects, which eliminates processing technology problems and reduces costs.

The liquid junction can be made of various conventionally used materials such as porous Teflon, porous ceramic, press-fitted plastic fibers, etc. The liquid junction holding part can be made of various materials such as porous Teflon, porous ceramic, press-fitted plastic fibers, etc. It is also possible to have a structure in which a replenishment port 40 is provided and the internal liquid is replenished from there.

[Brief explanation of drawings]

FIG. 1 is a view showing the upper end of the central axis body of a composite electrode that is an embodiment of the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG. 3 is a composite electrode that is an embodiment of the present invention. FIG. 4 is a cross-sectional view of a main part showing another embodiment of the present invention. 1... Center shaft body, 2... Space for storing measurement chip lead pins, 3... Packing storage space for fixing inner electrode lead wire of reference electrode, 4... Passage for inserting the lead wire of the inner electrode of the comparison electrode, 5...Space for storing thermistor, 6...Space for storing the measurement chip, 8...Screw part, 9... ...liquid junction holding part,
10... Liquid junction, 12... Packing, 14... Packing presser, 17...
Reference electrode inner electrode, 22...Thermistor, 30...
... Measuring chip, 34 ... Patsugyuu, 35
...Protective cap.

Claims (1)

[Claims] 1. A measurement chip lead pin storage space 2 formed with an open upper end, a measurement chip storage space 6 communicating with the space and formed with an open lower end, and a measurement chip lead pin storage space 2 outside the measurement chip lead pin storage space 2. Packing storage space 3 for fixing the inner electrode lead wire of the reference electrode, which is located at the upper end and is formed by opening the upper end.
and a thermistor storage space 5, a reference electrode inner electrode lead wire insertion passage 4 penetrating from the lower part of the packing storage space 3 to the lower center side wall, and a passage 4 formed on the outer peripheral wall at the lower end of the measurement chip storage space. A central shaft body 1 having a threaded portion 8 and integrally molded of plastic, a concentric cylindrical liquid contact reporting portion 9 removably provided on the outside of the central shaft body 1, and a liquid junction between the central shaft body 1 and the liquid junction. A comparison electrode inner electrode 17 provided in the space 16 between the holding parts 9, a packing 12 provided between the lower end of the liquid junction holding part and the center shaft body 1, and a packing screwed into the threaded part 8 of the center shaft body. It is characterized by a structure in which the internal liquid in the space 16 and the liquid junction holding part can be replaced by loosening the packing holder 14 and removing the packing 12. Composite electrode for measuring pH, etc.