# US 10,480,868 B2 · Tube assembly

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- Number: US 10,480,868 B2
- Document ID: US10480868B2
- Status: Granted
- Kind: B2
- Application number: 15/905,120
- Filed: 2018-02-26
- Published: 2018-07-05
- Granted: 2019-11-19
- Earliest claimed: 2014-07-03
- Assignees: United Technologies Corporation
- Applicants: United Technologies Corporation
- Inventors: Joe Ott; John J. Rup, Jr.; Stanley J. Funk; Dennis M. Moura; Lexia Kironn; Roger O. Coffey
- Web page: https://patentgrep.com/patent/US10480868B2

## CPC

- F28F 1/00: Tubular elements; Assemblies of tubular elements (specially adapted for movement F28F5/00)
- F23R 3/283: {Attaching or cooling of fuel injecting means including supports for fuel injectors, stems, or lances}
- F16L 9/18: Double-walled pipes; Multi-channel pipes or pipe assemblies
- F16L 59/14: Arrangements for the insulation of pipes or pipe systems (F16L59/02 - F16L59/12 take precedence)
- F23D 2211/00: Thermal dilatation prevention or compensation
- F23D 2900/00016: Preventing or reducing deposit build-up on burner parts, e.g. from carbon
- F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16)
- F23R: GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS (fluidised bed combustion apparatus specially adapted for operation at superatmospheric pressures F23C10/16)
- F16L: PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F23D: BURNERS

## Abstract

A tube assembly that may be for a fuel nozzle of a fuel system of a gas turbine engine may have a first tube defining a first flowpath along a centerline, a second tube generally spaced radially outward from the first tube with a first void located between and defined by the first and second tubes, and a support structure located in the first void and extending between the first and second tubes. The support structure is constructed and arranged to minimize or eliminate thermal conduction between the tubes. The entire assembly may be additive manufactured as one unitary piece. One example of a method of operation may include designed-for breakage of the structural support due to thermal stresses thereby further minimizing thermal conduction between tubes.

## Claims

### Claim 1

A method of operating a fuel system of a gas turbine engine comprising the steps of:
flowing a first fluid through a first flowpath defined by a first tube;
exposing a second tube surrounding and spaced radially outward from the first tube to a first thermal gradient; and
breaking a first sacrificial support structure located between the first and second tubes via thermal stress induced by the first thermal gradient.

### Claim 2 (depends on 1)

The method set forth in claim 1 comprising the further steps of:
flowing a second fluid through an annular second flowpath defined between the second tube and a third tube that is spaced from the second tube;
exposing the third tube to a second thermal gradient; and
breaking a second sacrificial support structure located between the second and third tubes via thermal stress induced by the second thermal gradient.

### Claim 3 (depends on 1)

The method set forth in claim 1, wherein the second tube is spaced radially outward from the first tube by a radial distance, and wherein the first sacrificial support structure has a length greater than the radial distance.

### Claim 4 (depends on 3)

The method set forth in claim 3, wherein the first flowpath is defined along a centerline, and wherein the first support structure lies in a plane that is normal to the centerline.

### Claim 5 (depends on 1)

The method set forth in claim 1, wherein the first flowpath is defined along a centerline, and wherein the first support structure lies in a plane that is normal to the centerline.

### Claim 6 (depends on 1)

The method set forth in claim 1, wherein the first sacrificial support structure has a thickness within a range of 0.004 to 0.008 inches.

### Claim 7 (depends on 1)

The method set forth in claim 1, wherein the first tube and the second tube define a void between the first tube and the second tube, and wherein the void is under a negative atmospheric pressure.

### Claim 8 (depends on 1)

The method set forth in claim 1, wherein the first support structure is one of a plurality of first support structures spaced circumferentially from one-another.