SU465585A1 - Electrochemical cell - Google Patents

Description

one

The invention relates to gas analyzers and can be used in determining the gas content in gaseous and liquid media.

There are known closed-type electrochemical cells for determining the gas content in the analyzed medium and consisting of a casing, a closed membrane permeable to the gas to be detected, and electrodes with their electrical leads.

With the aim of decreasing the detection fluidity, the membrane is made with a decrease in thickness to its n, center, and sprawled cathode in contact with the membrane at the site of its smallest thickness, and the cathode profile in the contact zone repeats the membrane profile.

Fig. 1 shows the design of the cell (it is used also by the oxygen pressure sensor).

The sensor consists of a polyethylene housing

1, made in one piece with the membrane

2, the silver cathode 3 and the lead anode 4. The space between the cathode 3 and the anode 4 is filled with insulating material 5, and between the case and the electrodes is a solution 6 of a twenty percent KOH. To seal the sensor body, they are fastened with a ring 7 and filled with a layer of varnish 8.

When the sensor is in operation, the oxygen of the medium being analyzed diffuses through membrane 2, mainly in the AB area, i.e. in the zone of minimum membrane thickness 2,

formed by a cathode 3 inserted with a tension. Passing through the membrane and the electrolyte layer, oxygen is ionized onto the surface of cathode 3 to form OH hydroxyl groups. In this case, through the load resistance connected to the sensor terminals, an electric current will flow, followed by the release of lead ions Pb + into the solution, which, neutralized by HE, remain on the surface of the aluminum in the hydroxide solution.

lead Pb (OH) 2.

The magnitude of the current flowing through the load is proportional to the number of the air reached by the cathode of the KCv, which, li according to the laws of diffusion, is proportional to the pOa

of the measured medium in the zone AB of the membrane 2. At the same time, localization of the measurement zone on the small surface of the membrane and the stability of the diffusion layer are achieved due to the close fit of the cathode to the membrane in this zone.

Subject invention

Electrochemical cell for determination of gas content in the analyzed medium, co3

the body of a gas-enclosed membrane permeable to gas and electrodes with leads is different, and in order to reduce the measurement error, the membrane is made with a decrease in

thickness to its center and stretched by the cathode in contact with the membrane in the place of its smallest thickness, and the profile of the cathode in the contact zone repeats the profile of the membrane.