US 5,851,369 A · Electrolytic sensor providing controlled burn-off of deposits on the electrodes

Abstract

A sensor having a working electrode, a solid electrolyte and a counter electrode forming an electrolytic cell within a protective casing is provided. The sensor is utilized for monitoring the concentration of a specific constituent within a sample fluid by measuring the electrical potential difference between the electrode exposed to the sample fluid, which is the working electrode, and the counter electrode, which is exposed to a reference fluid. A protective casing shields the electrolytic cell from the sample fluid and access to the working electrode is provided by sample fluid ports provided in the protective casing. To minimize the surface area of the working electrode exposed to the sample fluid, a restricter is placed in the channel defined by the protective casing and the working electrode. Additionally, a burn-off gas inlet port is provided to controllably supply burn-off gas to the working electrode surface to burn-off any residual film formed on the working electrode surface exposed to the sample fluid. Additionally, a control system is provided which can use the output from a potential measuring device to control the supply of burn-off gas to the working electrode surface.

Claims30

Dependent claims

A sensor, comprising;

a working electrode having an outer surface and an inner surface, a solid electrolyte having an outer surface and an inner surface, and a counter electrode having an outer surface and an inner surface, the inner surface of the working electrode being in contact with the outer surface of the solid electrolyte, the inner surface of the solid electrolyte being in contact with the outer surface of the counter electrode, and the inner surface of the counter electrode being exposed to a reference fluid;
an elongated protective casing arranged in spaced relation to the outer surface of the working electrode and defining a channel therebetween, the casing comprising a sample fluid port which permits a sample fluid to enter the channel;
a channel restrictor adjacent the sample fluid port, the channel restrictor defining a portion of the channel as a sensing zone and a portion of the channel as a non-sensing zone and reducing the volume of the channel which is exposed to the sample fluid;
a burn-off gas inlet adapted to inject a burn-off gas into the sensing zone, and
a burn-off gas in communication with the burn-off gas inlet, the burn-off gas having an oxygen concentration greater than an oxygen concentration in the sample fluid.

2 more elements

Dependencies are inferred from the claim text.

Electrolytic sensor providing controlled burn-off of deposits on the electrodes

Life of this patent

Electrolytic sensor providing controlled burn-off of deposits on the electrodes

Life of this patent

Abstract

Claims30