# US 11,306,968 B2 · Furnace system and method of use

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- Number: US 11,306,968 B2
- Document ID: US11306968B2
- Status: Granted
- Kind: B2
- Application number: 17/112,688
- Filed: 2020-12-04
- Published: 2021-06-10
- Granted: 2022-04-19
- Earliest claimed: 2019-12-04
- Assignees: Mantle Inc.
- Applicants: Mantle Inc.
- Inventors: Stephen T. Connor; Fabio Zurcher; Thale Smith
- Web page: https://patentgrep.com/patent/US11306968B2

## CPC

- F27B 5/04: adapted for treating the charge in vacuum or special atmosphere
- F27B 5/06: Details, accessories or equipment specially adapted for furnaces of these types
- F27B 5/16: Arrangements of air or gas supply devices
- F27B 5/18: Arrangement of controlling, monitoring, alarm or like devices
- F27D 7/02: Supplying steam, vapour, gases or liquids
- Y02P 10/25: Process efficiency
- F27B: FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27D: DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A sintering furnace can include an outer shell defining an internal volume a reactive agent inlet configured to introduce a reactive agent into the internal volume; an insulation chamber within the outer shell; and a retort configured to retain an object. A method of operating a sintering furnace can include sintering a part precursor within a retort arranged within a chamber, wherein the chamber defines an intermediate volume between the retort and the chamber, wherein a sintering byproduct is oxidized within the intermediate volume.

## Claims

### Claim 1

A sintering furnace comprising: an outer shell defining an internal volume, the outer shell comprising: an oxidizing agent inlet configured to introduce an oxidizing agent into the internal volume; andan exhaust mechanism configured to release a reaction byproduct from within the internal volume into an external environment; an insulation chamber arranged within the outer shell, wherein the insulation chamber comprises a heating element configured to raise a temperature inside the insulation chamber to at least a sintering temperature; and a retort, arranged within the insulation chamber, defining a retort volume, the retort comprising: an interfacing wall that separates the retort volume into a working volume and a gas introduction volume, wherein the working volume is configured to receive a material for sintering, wherein the interfacing wall defines a hole configured to allow fluid communication between the working volume and the gas introduction volume; and a gas inlet configured to provide a flow of inert gas into the gas introduction volume, wherein the gas introduction volume defines a tortuous path comprising a boustrophedonic cross-section, wherein the tortuous path is configured to increase a temperature of the inert gas prior to the inert gas entering the working volume wherein the oxidizing agent is introduced into the internal volume when a temperature of the insulation chamber is between 9000 C and 14000 C, wherein the inert gas is introduced in the retort volume contemporaneously with the introduction of the oxidizing agent into the internal volume.

### Claim 2 (depends on 1)

The sintering furnace of claim 1, wherein the exhaust mechanism does not include a catalytic converter, wherein the reaction byproduct comprises at most 10% undegraded sintering byproducts.

### Claim 3 (depends on 1)

The sintering furnace of claim 1, wherein the insulation chamber comprises a ceramic material comprising at least one of fibrous alumina, firebrick, alumina, alumina cement, or bubble alumina.

### Claim 4 (depends on 3)

The sintering furnace of claim 3, wherein the ceramic material releases a low dose of a second oxidizing agent during furnace operation.

### Claim 5 (depends on 1)

The sintering furnace of claim 1, further comprising a sensor configured to detect a quantity of carbon dioxide within or released from the internal volume.

### Claim 6 (depends on 5)

The sintering furnace of claim 5, wherein the oxidizing agent is introduced in response to detection of a threshold quantity of at least one of: carbon dioxide, carbon monoxide, oxygen, or water by the sensor.

### Claim 7 (depends on 1)

The sintering furnace of claim 1, wherein a gas pressure within the retort is greater than a gas pressure within the internal volume.

### Claim 8 (depends on 1)

The sintering furnace of claim 1, wherein a concentration of oxidizing agent in the internal volume does not exceed about 1000 ppm.

### Claim 9 (depends on 1)

The sintering furnace of claim 1, wherein the retort comprises at least one of graphite, silicon carbide, or carbon fiber composite.

### Claim 10 (depends on 1)

The sintering furnace of claim 1, wherein a sintering byproduct produced during object sintering is oxidized by the oxidizing agent in the internal volume.