Capacitive probe fabricating from spray deposition

Patent metadata

Field	Value
Publication number	US-9726777-B2
Application number	US-201314761994-A
Country	US
Kind code	B2
Filing date	Jan 23, 2013
Priority date	Jan 23, 2013
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

A proximity sensor includes a lead supported on an outer surface of a case structure and a sensor wire that extends from the lead and through an opening in the case structure. The sensor is formed by applying alternating layers of electrically conductive and non-conductive materials in a non-cured state. A base non-conductive layer is applied to an inner surface of the case structure around the sensor wire in a non-cured state. Once cured, a conductive layer is deposited onto the base non-conductive layer and encapsulates the sensor wire. A cover non-conductive layer is then deposited over portions of the conductive layer to insulate the conductive layer. Portions of the non-conductive layer are then removed such that an area of the conductive layer is exposed to define a sensor area.

First claim

What is claimed is:

1. A method of fabricating a proximity sensor comprising:
mounting a lead within an opening of a substrate;
extending a sensor wire that extends from the lead through the opening in the substrate;
depositing a base electrically non-conductive layer with a cure in place process onto the substrate and around the sensor wire;
encapsulating the sensor wire within an electrically conductive layer deposited onto the base non-conductive layer with a cure in-place process, wherein an end of the sensor wire is held within the electrically conductive layer;
applying a cover non-conductive layer over the conductive layer with a spray deposition process; and
removing a portion of the non-conductive layer to expose a portion of the electrically conductive layer.

2. The method as recited in claim 1 , wherein encapsulating the sensor wire within a conductive layer comprises depositing a first conductive layer onto the base non-conductive layer, adhering the sensor wire to the first conductive layer and depositing a second conductive layer over the first conductive layer and the sensor wire.

3. The method as recited in claim 1 , including the step of masking an area for the base non-conductive layer and depositing non-conductive material within the masked area.

4. The method as recited in claim 1 , including the step of defining a sensor area with a mask and depositing the conductive layer encapsulating the sensor wire within the sensor area.

5. A method of mounting a proximity sensor within a gas turbine engine comprising:
forming an opening within a case structure proximate a rotating structure, wherein the opening is formed through an outer surface of the case structure and includes a bottom surface;
mounting a lead into the opening;
extending a sensor wire extending from the lead through a second opening through the bottom surface to an inner surface of the case structure;
depositing a base non-conductive layer with a thermal spray process onto the inner surface of the case structure around the sensor wire;
encapsulating the sensor wire within a conductive layer deposited onto the base non-conductive layer with a thermal spraying process;
depositing a non-conductive abraidable layer over the conductive layer; and
removing a portion of the abraidable layer to expose the conductive layer.

6. The method as recited in claim 5 , including depositing a cover non-conductive layer over the conductive layer prior to depositing the abraidable layer and removing both the cover non-conductive layer and the abraidable layer to expose the conductive layer.

7. The method as recited in claim 5 , wherein encapsulating the sensor wire within a conductive layer comprises depositing a first conductive layer onto the base non-conductive layer, adhering the sensor wire to the first conductive layer and depositing a second conductive layer over the first conductive layer and the sensor wire.

8. The method as recited in claim 5 , including removing a portion of the abraidable layer to define a shape of the proximity sensor.

9. The method as recited in claim 5 , wherein the thermal spraying process comprises a plasma deposition spray process.

10. The method as recited in claim 5 , including mounting a lead within a ferrule and mounting the ferrule to the case structure proximate the opening.

11. The method as recited in claim 10 , including brazing the lead to the ferrule and welding the ferrule to the case structure.

12. A proximity sensor comprising:
a lead supported within an opening through an outer surface of a case structure, the opening including a bottom surface;
a sensor wire extending from the lead through a second opening through the bottom surface to an inner surface of the case structure;
a base non-conductive layer thermally applied to the inner surface of the case structure around the sensor wire;
a conductive layer thermally deposited onto the base non-conductive layer and encapsulating the sensor wire; and
a cover non-conductive layer thermally deposited over portions of the conductive layer such that an area of the conductive layer is exposed to define a sensor area.

13. The proximity sensor as recited in claim 12 , wherein the conductive layer comprises a first conductive layer applied to the base non-conductive layer, wherein the sensor wire is adhered to the first conductive layer and a second conductive layer encapsulating the sensor wire adhered to the first conductive layer.

14. The proximity sensor as recited in claim 13 , wherein the sensor wire is in electrical conductive contact with the conductive layer.

15. The proximity sensor as recited in claim 12 , including a ferrule supporting the lead and attached to the case structure.

16. The proximity sensor as recited in claim 15 , including an abraidable layer deposited over the cover non-conductive layer and the conductive layer is exposed and countersunk relative to the abraidable area.

Assignees

• United Technologies Corp

Inventors

• Warren Eli Cole
• Negash Jerusalem

Classifications

• B05D5/02

  to obtain a matt or rough surface · CPC title

• B05D1/32

  using means for protecting parts of a surface not to be coated, e.g. using stencils, resists · CPC title

• G01B7/22

  using change in capacitance · CPC title

• H03K17/955 Primary

  using a capacitive detector · CPC title

• B23K31/02

  relating to soldering or welding · CPC title