Ceramic coating for heated fuel filter

Patent metadata

Field	Value
Publication number	US-2016273455-A1
Application number	US-201415024675-A
Country	US
Kind code	A1
Filing date	Dec 11, 2014
Priority date	Dec 16, 2013
Publication date	Sep 22, 2016
Grant date	—

Abstract

A fuel filter comprises a filter screen, a heating element, and a coating. The filter screen includes a first hollow member. The heating element is disposed within the first hollow member. The coating is formed of a thermally conductive, electrically insulating ceramic in a hydrodynamic filtering pattern surrounding the filter screen but having a different shape than a shape of the hollow member.

First claim

1 . A fuel filter comprising:
a filter screen including a first hollow member; a heating element disposed within the first hollow member; and a coating formed of a thermally conductive, electrically insulating ceramic in a hydrodynamic filtering pattern surrounding the filter screen but having a different shape than a shape of the hollow member.

2 . The fuel filter of claim 1 , wherein the heating element is an electrically resistive heater.

3 . The fuel filter of claim 1 , wherein the filter screen has a mesh dimension of less than 1400 microns.

4 . The fuel filter of claim 1 , wherein the filter screen is formed of a first material with a first coefficient of thermal expansion, and the coating is formed of a second material with a second coefficient of thermal expansion that is substantially similar to the first coefficient of thermal expansion

5 . The fuel filter of claim 1 , wherein the hydrodynamic filtering pattern includes a plurality of bellmouth apertures.

6 . The fuel filter of claim 5 , wherein each of the bellmouth apertures has a minimum aperture diameter at or near a vena contracta of fluid flow through the bellmouth aperture.

7 . The fuel filter of claim 5 , wherein the filtering pattern includes guide points projecting upstream into the fluid at intersections of the filter screen.

8 . The fuel filter of claim 1 , wherein the filtering pattern is formed via a thick film deposition process whereby the filter screen is deposited inside the coating, and the filter screen and coating are cured simultaneously.

9 . The fuel filter of claim 1 , wherein the filter screen comprises at least one of copper and tungsten.

10 . The fuel filter of claim 9 , wherein the coating is a ceramic formed of Beryllia (Beryllium Oxide), Alumina (Aluminum Oxide), Aluminum Nitride, or combinations thereof, with substantially the same coefficient of thermal expansion as copper between −55° C. (−67° F.) and 200° C. (392° F.).

11 . The fuel filter of claim 9 , wherein the coating is a ceramic formed of Beryllia (Beryllium Oxide), Alumina (Aluminum Oxide), Aluminum Nitride, or combinations thereof, with substantially the same coefficient of thermal expansion as tungsten between −55° C. (−67° F.) and 200° C. (392° F.).

12 . A fuel system for a gas turbine engine, the fuel system comprising:
a pump configured to draw fuel from a fuel tank; a fluid line configured to carry fuel from the pump to a combustor of the gas turbine engine; a fuel filter disposed on the fluid line, and comprising:
an electrically resistively heated filter screen; and
a coating formed of a thermally conductive, electrically insulating ceramic in a hydrodynamic filtering pattern surrounding at least a portion of the heated filter screen.

13 . The fuel system of claim 12 , wherein the hydrodynamic filtering pattern has a different shape than a shape of the resistively heated filter screen.

14 . The fuel system of claim 13 , wherein the resistively heated filter screen defines a grid, and the hydrodynamic filtering pattern includes a plurality of bellmouth apertures situated at openings of the grid.

15 . The fuel system of claim 14 , wherein the hydrodynamic filtering pattern further comprises guide points projecting in an upstream direction into the fuel at intersections of the grid.

16 . A method for filtering fuel in a gas turbine engine fuel system, the method comprising:
moving a fluid through a filter screen, the filter screen comprising at least one electrically resistive heating element, the filter screen comprising:
a mesh formed of a plurality of filter elements within the gas turbine engine fuel system, such that the filter screen forms openings having a first perimeter with a substantially rectangular shape, the at least one electrically resistive heating element disposed within at least one of the plurality of filter elements;
a thermally conductive, electrically insulating ceramic coating on the mesh, such that the openings have a second perimeter that includes at least one curved portion; and
heating the fluid by running current through the electrically resistive heating element.

17 . The method of claim 16 , wherein the filter screen and the thermally conductive, electrically insulating ceramic coating are formed of materials with substantially identical coefficients of thermal expansion.

18 . The method of claim 17 , wherein the filter screen comprises at least one of copper and tungsten.

19 . The method of claim 16 , wherein the thermally conductive, electrically insulating ceramic coating forms a bellmouth aperture at each of the openings.

20 . The method of claim 19 , wherein each of the bellmouth apertures has a minimum aperture diameter at or near a vena contracta of fluid flow through the bellmouth aperture.

Assignees

• United Technologies Corp

Inventors

• Fausett Taylor
• Wasson Patrick M

Classifications

• F02C7/224 Primary

  Heating fuel before feeding to the burner · CPC title

• F05D2220/30

  in turbines · CPC title

• B64D41/00

  Power installations for auxiliary purposes · CPC title

• B64D37/34

  Conditioning fuel, e.g. heating (during filling B64D37/18) · CPC title

• B01D35/18

  Heating or cooling the filters · CPC title