Sensor housing apparatus providing a hermetic seal
Apparatus having a hermetic seal that seals a portion of the apparatus, for example and without limitation, a portion having a MEMS sensor.
1. An apparatus having a hermetic seal comprising: a housing with a top and bottom and a hole that passes through the housing from the top to the bottom, wherein the housing further comprises: a first cavity that extends down into the housing from the top and is coaxial with the hole, and a second cavity that extends down into the housing from the top and surrounds, and is coaxial with, the first cavity, and a cavity wall formed between the first cavity and the second cavity; a radial seal that is cylindrically shaped with an axial height greater than a radial thickness inside the first cavity; an isolation member coupled to a sensor and located within the cylindrically shaped radial seal in the first cavity such that the radial seal is located between the isolation member and the cavity wall; a collar pressed into the second cavity such that the cavity wall is crimped down onto the radial seal and isolation member to provide a hermetic seal between the isolation member and the housing.
2. The apparatus of claim 1 wherein the radial seal is comprised of a soft metal.
3. The apparatus of claim 2 wherein:
the collar has a first hole that passes through the collar wherein, the first hole is coaxial with the hole, first cavity and second cavity.
4. The apparatus of claim 3 wherein the sensor is a pressure sensor.
5. The apparatus of claim 1 wherein the radial seal is comprised of soft copper.
6. The apparatus of claim 5 wherein the housing is comprised of one or more of stainless steel, brass and aluminum.
7. The apparatus of claim 1 wherein the radial seal is comprised of a copper alloy.
8. The apparatus of claim 1 , wherein the radial seal is press fit inside the first cavity.
9. The apparatus of claim 1 wherein the collar is comprised of steel.
10. The apparatus of claim 9 wherein the steel is high strength stainless steel.
11. The apparatus of claim 1 wherein:
the radial seal fits snugly inside the cavity wall.
12. The apparatus of claim 11 wherein the sensor is a pressure sensor.
13. The apparatus of claim 1 wherein the sensor is a MEMS sensor.
14. The apparatus of claim 1 wherein the housing is cylindrically shaped.