Measuring and testing – Gas analysis – Gas of combustion
Patent
1996-11-05
1999-07-13
Williams, Hezron
Measuring and testing
Gas analysis
Gas of combustion
73 3105, 204426, G01N 700, G01N 2726
Patent
active
059229381
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a gas sensor, preferably a lambda sensor for determining the pollutant and/or oxygen content in exhaust according to the preamble of Claim 1.
Gas sensors according to the species are known (DE-42 04 850 A1) and have a ceramic part located in a protective housing to receive a sensor support that carries the sensor element itself at the end exposed to the exhaust, and whose other end projects into the contact area of contact elements. The contact elements contained in the ceramic part are in a conducting relationship with the electrical terminals projecting out of the protective housing.
For manufacturing reasons, the ceramic part is made of two pieces arranged mirror-image-fashion with respect to one another and having an identical shape, the shape of said pieces being designed so that, when the pieces are correctly positioned on top of one another, both the sensor support and the contact elements are fixed in position in the ceramic part.
Ceramic parts of this kind, because of the parting plane running in the lengthwise direction of the gas sensor, allow simple insertion and assembly of both the sensor support and the contact elements; however they have a relatively large parting plane. This imposes special requirements on the plane-parallelism of the two parting planes located opposite one another which, during the stoving process, for example during sintering of the two pieces, cannot always be met or can be met only with relatively high expense. If the two parting planes are not perfectly plane-parallel, sealing problems will occur.
The goal of the invention is to provide a gas sensor whose installation costs are minimized by ease of assembly of its individual parts.
This goal is achieved in a gas sensor according to the species by the characterizing features of the main claim.
As a result of the positive fit that prevails between the metal housing and the ceramic part, the latter is held in an extremely simple and secure fashion in the radial direction in the metal housing, and the gas-sealing surfaces provide a seal for the gas escaping from the exhaust chamber. If this positive fit is designed as a tapered connection and the taper ratio is chosen accordingly, an axial locking of the ceramic part is achieved, so that an additional sealing element possibly located between the ceramic part and the metal housing is exposed only to a pressure that is considerably reduced by comparison to the pressure prevailing in the exhaust chamber.
Further advantageous embodiments and improvements as well as advantages follow from the subclaims.
The invention will now be described in greater detail with reference to a preferred embodiment shown in the drawings.
FIG. 1 is a lengthwise section through the gas sensor according to the invention;
FIG. 2 is a top view of FIG. 1, partially cut away; and
FIG. 3 is a side view of the gas sensor.
The gas sensor designated as a whole by 1 in FIG. 1 has a metal housing 2 provided with a screw thread 3 at its end facing the exhaust. An Allen wrench 4 is associated with screw thread 3, with the aid of which wrench gas sensor 1 can be screwed into a matching thread of an exhaust chamber, not shown, with a sealing ring 5 in between.
At its forward end, metal housing 2 has a cylindrical projection 6 that serves to receive a protective sheath 7 for a sensor support 8 with sensor elements 9 located on it and printed for example. Protective sheath 7 is provided in a manner known of itself with feedthroughs 10 so that the exhaust can flow around sensor element 9.
A ceramic part 11 serves to receive sensor support 8, said part having a feedthrough slot 12 for the sensor support and projecting into the exhaust chamber, not shown, with its (at least) one sensor element mounted thereon. For a gas-tight seal of feedthrough 12 in its area facing the exhaust, the feedthrough can be potted or sensor support 8 can be glued in feedthrough 12. Two recesses 40, 41 are also provided for this purpose, with a temperature-resistant and less gas-tight sealing material, ceramic adhe
REFERENCES:
patent: 4214472 (1980-07-01), Maxwell et al.
patent: 4320378 (1982-03-01), Taniguchi et al.
patent: 4489596 (1984-12-01), Linder et al.
patent: 4883643 (1989-11-01), Nisshio et al.
patent: 5039972 (1991-08-01), Kato et al.
patent: 5246562 (1993-09-01), Weyl et al.
patent: 5467636 (1995-11-01), Thompson et al.
patent: 5490412 (1996-02-01), Duce et al.
patent: 5546787 (1996-08-01), Hafele et al.
patent: 5602325 (1997-02-01), McClanhan et al.
patent: 5616825 (1997-04-01), Ache et al.
Heraeus Electro-Nite International,N.V.
Politzer Jay L.
Williams Hezron
LandOfFree
Gas sensor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Gas sensor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gas sensor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2277158