Electrochemical sensor including a measuring cell and an oxidation component and process using such a sensor

An arrangement comprising:

• an electrochemical sensor for detecting a predetermined gas component in a gas and/or for measuring a concentration of the gas component in the gas, the electrochemical sensor comprising:
• a housing enclosing an interior space;
• a measuring cell side inlet in the housing, the measuring cell side inlet being configured to provide fluid communication between the interior space and an environment of the electrochemical sensor;
• a pressure equalization outlet in the housing, the pressure equalization outlet being configured to provide fluid communication between the interior space and an environment of the electrochemical sensor;
• a measuring cell in the interior space, the measuring cell arranged between the measuring cell side inlet and the pressure equalization outlet and configured such that a chemical reaction takes place at the measuring cell which depends on the concentration of the gas component in the interior space and influences a measurable electrical variable, the measuring cell comprising:
• a measuring electrode;
• a counter electrode;
• and
• an electrically insulating and ionically conductive layer between the measuring electrode and the counter electrode;
• an electrical measuring unit configured to measure an indicator of the influenced electrical variable;
• and
• an oxidation component arranged in the interior space between the pressure equalization outlet and the measuring cell and at a distance from the measuring cell, the oxidation component being electrically isolated from the measuring cell and being arranged and configured to oxidize an oxidizable component in the gas passing from outside the housing through the pressure equalization outlet into the interior space;
• an adapter configured to be detachably mounted on the housing;
• and
• a fluid guiding unit fluid-tightly connected to the adapter, wherein with the adapter mounted on the housing, the measuring cell side inlet is in fluid communication with an environment of the electrochemical sensor only through the fluid guiding unit.

A process for detecting a predetermined gas component in a gas and/or for measuring a concentration of the gas component in the gas, the process comprising the steps of:

• providing an electrochemical sensor comprising a housing enclosing an interior space;
• a measuring cell side inlet in the housing;
• a pressure equalization outlet in the housing;
• a measuring cell arranged in the interior space between the measuring cell side inlet and the pressure equalization outlet, the measuring cell comprising:
• a measuring electrode;
• a counter electrode;
• and an electrically insulating and ionically conductive layer between the two electrodes;
• an electrical measuring unit;
• and an oxidation component in the interior space between the pressure equalization outlet and the measuring cell and at a distance from the measuring cell, wherein the oxidation component is electrically conductive and is electrically isolated from the measuring cell, wherein both the measuring cell side inlet and the pressure equalization outlet at least temporarily provide fluid communication between the interior space and an environment of the electrochemical sensor;
• allowing a sample of the gas to flow through the measuring cell side inlet into the interior space and to reach the measuring cell;
• allowing a chemical reaction to take place at the measuring cell which reaction depends on the concentration of the gas component in the interior space and influences a measurable electrical variable;
• measuring an indicator of the influenced electrical variable with the electrical measuring unit;
• and
• oxidizing an oxidizable component in the gas passing from outside the housing through the pressure equalization outlet into the interior space with the oxidation component.