JPH0321482Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a galvanic cell type oxygen sensor. More specifically, the present invention relates to a galvanic cell type oxygen sensor comprising a positive electrode made of a catalytic electrode effective for electrolytic reduction of oxygen, a negative electrode made of lead, an electrolytic solution, a diaphragm, and a container.

Galvanic cell-type oxygen sensors are small, lightweight, operate at room temperature, and are inexpensive, so they can be used to check oxygen deficiency conditions in ships and manholes, and to check oxygen concentration in medical equipment such as anesthesia machines and artificial respirators. It is used in a wide range of fields, such as for monitoring.

BACKGROUND OF THE INVENTION A galvanic cell type oxygen sensor typically consists of a positive electrode consisting of a catalytic electrode effective in the electrolytic reduction of oxygen, a negative electrode consisting of lead, an electrolyte, a diaphragm, and a container.

Conventionally, the diaphragm and the positive electrode are of a type in which they are simply in contact (for example, Japanese Patent Application Laid-open No. 187846/1982), and in others they are integrally joined (for example, British Patent No. 1200595). The present invention relates to the latter type.

Problems that the invention aims to solve: Diaphragm-cathode assemblies are generally thin and fragile;
One issue was how to collect the current.
Conventionally, proposals have also been made in which, for example, a metal spring is used as a current collector and is pressed into contact with the positive electrode. However, there is a problem in that installing the metal spring in a narrow space is extremely complicated. Another problem was that the metal spring caused damage to the positive electrode.

Means to Solve the Problems The present invention provides a presser plate, an O-ring, a porous protective film, a diaphragm, a positive electrode, an electrolytic solution, and a current collector between a threaded container body having an inner partition and a threaded container lid. A sensor component consisting of a porous carbon membrane with a liquid retention function and a metal wire for current collection is housed, and the sensor component is fixed by screwing the container body and the container lid. A negative electrode made of lead and an electrolyte are stored in a compartment located on the opposite side of the container lid in the internal partition of the main body, and
At least two perforations are provided in the aforementioned partition,
Moreover, by providing a groove between one perforation and another perforation, and fitting a current collecting metal wire bent into a substantially square shape into the perforation and the groove, the above-mentioned method can be achieved. It attempts to solve problems.

Operation By adopting the structure of the present invention, the operation is simple because the current collecting metal wire is first inserted into the perforation. Further, since the current collecting metal wire is fitted into the perforation and the groove, it is securely fixed. Furthermore, since a part of the current collecting metal wire is fitted into the groove and there are few protrusions, the porous carbon film in contact with the current collecting metal wire will not be damaged. The positive electrode and the metal wire for current collection, together with the porous carbon film, are pressed into contact with each other by screwing the container body and the container lid, and electrical contact is maintained. As the metal wire material for current collection, nickel is used when the electrolyte is alkaline, and titanium or tantalum is used when the electrolyte is acid.

Embodiment FIG. 1 shows a cross-sectional structure of a galvanic cell type oxygen sensor according to an embodiment of the present invention.

Between the partition part 2 of the container body 1 and the container lid 3, there is a press plate 4, a porous protective film 5 made of a porous polytetrafluoroethylene film, O-rings 6, 6', and a tetrafluoroethylene-6 film. A diaphragm 7 made of a chlorinated propylene copolymer film, a positive electrode 8 made of gold, a porous carbon paper 9 having functions as an electrolyte holder and a current collector, and a titanium wire bent in a square shape. A current collecting metal wire 10 is housed therein and fixed with screws. Diaphragm 7
A positive electrode 8 is integrally joined by a sputtering method.

Inside the container body 1 , an electrolytic solution 10 made of a mixed aqueous solution of acetic acid, potassium acetate, and lead oxide, and a negative electrode 12 made of lead are housed. Between the positive and negative electrodes,
A thermistor 13 and a resistor 14 are connected, and the voltage between the positive and negative terminals becomes the output of this galvanic cell type oxygen sensor, which has linearity with the oxygen concentration.

The metal wire 10 for current collection is inserted into the perforation 15 of the partition part 2,
15' and the groove 16.

Effects of the invention As mentioned earlier, the features of this invention are (1) that the current collecting metal wire is easy to store and fix, and (2) that the current collecting metal wire is porous as a positive electrode or as an intermediate current collector. The advantage is that it does not damage the carbon film. For example, a galvanic cell type oxygen sensor according to an embodiment of the present invention and a conventional sensor using metal as a current collector, respectively.
After preparing 10 sensors and leaving them in an atmosphere of 100% oxygen at 37°C for half a year, we dismantled and inspected all the sensors, and found that no abnormalities were observed with the inventive product, whereas with the conventional product. , out of 10
In three cases, a phenomenon in which the gold serving as the positive electrode partially peeled off from the diaphragm was observed.

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional structure of a galvanic cell type oxygen sensor according to an embodiment of the present invention. 1 ... Container body, 2... Inner partition, 3... Container lid, 4... Holding plate, 7... Diaphragm, 8... Positive electrode,
9...Carbon paper, 10...Metal wire for current collection, 11...Electrolyte solution, 12...Negative electrode, 15,1
5'...Perforation, 16...Groove portion.

Claims (1)

[Scope of utility model registration request] A porous carbon membrane having a holding plate, an O-ring, a porous protective film, a diaphragm, a positive electrode, an electrolyte, a current collecting function, and a liquid retaining function between a threaded container body having a partition and a threaded container lid. The sensor component consisting of a metal wire for current collection, etc. is housed, and the sensor component is fixed by screwing the container body and the container lid. A negative electrode made of lead and an electrolyte are housed in the chamber, and at least two perforations are provided in the partition, and a groove is provided between one perforation and another perforation, and further,
The tip of the metal wire for current collection, which is bent into a substantially square shape, is fitted into one of the holes, a part of it is fitted into the groove, and a part of the metal wire is passed through the other hole to form a galvanic cell type oxygen sensor. A galvanic cell-type oxygen sensor characterized by being connected to the positive terminal of a.