US 4,728,411 AGranted

Electrochemical device

AssigneeNGK Insulators, Ltd.

InventorsSyunzo Mase, Shigeo Soejima

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Abstract

An electrochemical device of a laminar structure for determining the concentration of a component in a measurement gas, comprising: a pumping cell including a first and a second electrode disposed on a first planar solid electrolyte body; a sensing cell including a third and a fourth electrode disposed on a second planar solid electrolyte body; and a thin flat space to which the first and third electrodes are exposed and which communicates with an external space in which the measurement gas exists. The thin flat space has a diffusion resistance to the component in the measurement gas introduced through an inlet thereof. The first and third electrodes and the thin flat space are positioned and dimensioned relative to each other so that a distance "l" is smaller than a distance "m", as measured in a cross section perpendicular to planes of the solid electrolyte bodies, where the distance "l" is measured between the inlet of the thin flat space and a point of the first electrode nearest to the inlet as measured in the above-indicated cross section, and the distance "m" is measured between the inlet and a point of the third electrode nearest to the inlet as measured in the above-indicated cross section.

Claims22

Dependent claims

An electrochemical device for determining the concentration of a component in a measurement gas, comprising:

a plurality of superposed planar layers;
an electrochemical pumping cell including a first planar solid electrolyte body and at least a first electrode and a second electrode disposed in contact with said first planar solid electrolyte body, said first electrode having an innermost transverse end and an outermost transverse end;
an electrochemical sensing cell including a second planar solid electrolyte body, and a third electrode and a fourth electrode disposed in contact with said second planar solid electrolyte body, said third electrode having an innermost transverse end and an outermost transverse end;
and
means for defining a transverse measurement-gas space having a transverse axis, said measurement-gas space communicating with an external space in which the measurement gas exists through an inlet opening, said inlet opening and transverse measurement-gas space having a predetermined diffusion resistance to said component in the measurement gas which is to be measured, said first electrode of the electrochemical pumping cell and said third electrode of the electrochemical sensing cell communicating with said measurement-gas space, wherein said outermost transverse end of said first electrode is located a distance "l" from said inlet along said transverse axis and said outermost transverse end of said third electrode is located a distance "m" from said inlet along said transverse axis, and said first and third electrodes are located on opposite sides of said measurement-gas space and are separated by a distance "w", such that the following relationship is satisfied:
m-l.gtoreq.5w,
such that an average oxygen concentration along a transverse direction of said third electrode in communication with said measurement-gas space is less than an average oxygen concentration along a transverse direction of said first oxygen concentration along a transverse direction of said first electrode in communication with said measurement-gas space.

4 more elements

An electrochemical device for determining the concentration of a component in a measurement gas, comprising:

a plurality of superposed planar layers;
an electrochemical pumping cell including a first planar solid electrolyte body and at least a first electrode and a second electrode disposed in contact with said first planar solid electrolyte body, said first electrode having an innermost transverse end and an outermost transverse end;
an electrochemical sensing cell including a second planar solid electrolyte body, and a third electrode and a fourth electrode disposed in contact with said second planar solid electrolyte body, said third electrode having an innermost transverse end and an outermost transverse end;
and
means for defining a transverse measurement-gas space having a transverse axis, said measurement-gas space communicating with an external space in which the measurement gas exists through an inlet opening, said inlet opening and transverse measurement-gas space having a predetermined diffusion resistance to said component in the measurement gas which is to be measured, said first electrode of the electrochemical pumping cell and said third electrode of the electrochemical sensing cell communicating with said measurement-gas space, wherein said outermost transverse end of said first electrode is located a distance "l" from said inlet along said transverse axis and said outermost transverse end of said third electrode is located a distance "m" from said inlet along said transverse axis, and said first and third electrodes are located on opposite sides of said measurement-gas space and are separated by a distance "w", such that the following relationship is satisifed:
m-l.gtoreq.5w,
such that an average oxygen concentration along a transverse direction of said first electrode in communication with said measurement-gas space is intermediate between an average oxygen concentration within said transverse measurement-gas space and an average oxygen concentration along a transverse direction of said third electrode in communication with said measurement-gas space.

4 more elements

Dependencies are inferred from the claim text.