Sensor for determinig the oxygen concentration in gases

Claim 1

Sensor for determining the oxygen concentration in gases, particularly in exhaust gases of internal combustion engines, having a measuring element which consists only of solid substances and which is partly sealingly surrounded by a tubular metal housing and whose portion exposed to the gases to be measured is provided with a beaker-like protective tube whose one end portion is fastened to the metal housing while its other regions surround and are spaced apart from that portion of the measuring element which on the side of the gas to be measured projects out of the metal housing, said protective tube having for the gases to be measured an opening in its bottom on the side of the gas to be measured and a plurality of openings, provided with deflector means, in its side wall, characterized in that the bottom (21) of the protective tube (18), on the side of the gas to be measured, is in the form of a convex dome and in its furthest projecting region has a nipple-like bulge (22) in which is provided the opening (23) for the admission of the gases to be measured, and that a plurality of openings (25) intended as outlets for the gases to be measured are provided close to that end of the metal housing (14) which is near the gas to be measured and have deflector means (26) in the form of tabs cut into and bent out from the protective tube (18), the free ends of said tabs projecting into the protective tube, being directed towards the end portion of the sensor (10) remote from the gas to be measured, and consequently directing back in the outward direction, at an acute angle to the longitudinal axis of the protective tube (18), the gases flowing through the protective tube (18) in the longitudinal direction.