Vented high-temperature piezoelectric-based field device
View Patent ↗A process fluid sensor for sensing a characteristic of a process fluid is provided. The process fluid sensor includes a metallic sensor body that defines a chamber therein. A piezoelectric crystal element is disposed proximate the chamber and is configured to generate an electrical signal in response to a mechanical input. The piezoelectric crystal element is mechanically coupleable to the process fluid, but is sealed within the sensor body with the exception of a gaseous pathway. A vortex flowmeter utilizing the process fluid sensor is also provided.
1. A process fluid sensor for sensing a characteristic of a process fluid, the sensor comprising:
a metallic sensor body defining a chamber therein;
a piezoelectric crystal element disposed proximate the chamber and configured to generate an electrical signal in response to a mechanical input;
wherein the piezoelectric element is mechanically coupleable to the process fluid, and is sealed within the sensor body; and
an oxygen diffusion path configured to convey oxygen to the piezoelectric element.
2. The process fluid sensor of claim 1 , wherein the sensor is a vortex sensor.
3. The process fluid sensor of claim 2 , wherein the oxygen diffusion path is configured to inhibit liquid flow therethrough.
4. The process fluid sensor of claim 3 , wherein the oxygen diffusion path is formed through a porous metallic component.
5. The process fluid sensor of claim 4 , wherein the porous metallic component is a pull post of the vortex sensor.
6. The process fluid sensor of claim 4 , wherein the porous metallic component has a density that is less than a solid construction of the component.
7. The process fluid sensor of claim 6 , wherein the density of the metallic component is about 90% of a solid component.
8. A vortex flowmeter comprising:
an electronics housing containing transmitter electronics;
a vortex sensor coupled to the transmitter electronics, the vortex sensor including:
a metallic sensor body defining a chamber therein;
a piezoelectric element disposed proximate the chamber and configured to generate an electrical signal in response to a mechanical input; and
wherein the piezoelectric element is mechanically coupleable to the process fluid, and is sealed within the sensor body; and
an oxygen diffusion path configured to convey oxygen to the piezoelectric element.
9. The vortex flowmeter of claim 8 , wherein the oxygen diffusion path is configured to inhibit liquid flow therethrough.
10. The vortex flowmeter of claim 9 , wherein the oxygen diffusion path is formed through a porous metallic component.
11. The vortex flowmeter of claim 10 , wherein the porous metallic component is a pull post of the vortex sensor.
12. The vortex flowmeter of claim 8 , wherein the electronics enclosure is mounted proximate the vortex sensor.
13. A pull post of a vortex flowmeter, the pull post being sized to be received by an aperture within a vortex sensor, wherein the pull-post seals a chamber within the vortex sensor except for an oxygen pathway through the pull post.
14. The pull post of claim 13 , wherein the pull post is formed of a porous metal.