Retort with Peclet Seal and Fore Volume for Sintering

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Solution Overview

Problem

Existing retorts for thermal processing of sinterable objects are insufficient in controlling and mitigating the entry of undesirable chemical and thermal conditions, leading to contamination and process failures during sintering.

Innovation Solution

The design of an improved retort with a Peclet seal on the outlet, a fore volume for gas cleansing, and construction from low-permeability materials, along with a limited number of inlets and outlets, to maintain a controlled atmosphere and reduce contaminant transport, ensuring the retort's sealing surfaces experience temperature profiles identical to the objects being processed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing retort designs are used, then the retort structure is simple and easy to manufacture, but the retort is insufficient in controlling and mitigating the entry of undesirable chemical and thermal conditions, leading to contamination and process failures

Engineering Contradiction:
Improveprocess reliabilityVSAvoidretort structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The retort is divided into multiple functional zones including a forevolume separated from the sintering volume by a diaphragm seal, and further segmentation of gas flow paths through multiple seals (primary seal, secondary seal, tertiary seal). This segmentation allows independent control of atmospheric conditions in different regions, improving reliability by isolating contamination sources while maintaining manageable structural complexity through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A diaphragm seal acts as an intermediary barrier between the forevolume and the sintering volume, controlling gas flow and preventing direct contamination. Additionally, a lapped seal between the forevolume housing and retort housing serves as an intermediary sealing mechanism. These intermediary elements improve process reliability by providing controlled transition zones without requiring complete redesign of the entire retort structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the retort uses a controlled atmosphere to protect objects during sintering, then contamination is reduced, but undesirable gaseous species such as water, oxygen, and hydrocarbons may still enter and cause chemical changes or process failure

Engineering Contradiction:
Improvecontaminant ingressVSAvoidprocess consistency
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The Peclet seal is positioned at the retort outlet to prevent backflow of contaminants into the sintering volume before contamination can occur. The forevolume with its diaphragm seal creates a preliminary barrier that filters and controls gas composition before it enters the main sintering chamber. These preliminary protective measures consistently maintain atmosphere quality, improving process reliability while effectively blocking harmful factors.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The forevolume is designed to tolerate and manage the presence of undesirable gaseous species by providing a sacrificial zone where contaminants can be contained and controlled without directly affecting the sintering volume. The diaphragm seal allows selective gas permeation, converting potentially harmful backflow into a controlled atmospheric exchange that actually protects the main process volume, thereby improving consistency.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of operation

If multiple inlets and outlets are provided in the retort, then gas flow control is improved, but the number of sealing surfaces increases, creating more potential leak paths for contaminants

Engineering Contradiction:
Improvegas flow controlVSAvoidleak paths for contaminants
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The diaphragm seal uses a flexible thin film structure that provides effective sealing across the gas flow path between forevolume and sintering volume. This flexible membrane sealing approach maintains ease of gas flow control through multiple openings while minimizing leak paths, as the thin film conformally seals around flow components. Similarly, the lapped seal uses a flexible sealing surface that adapts to thermal expansion, maintaining sealing integrity despite operational variations.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

Multiple sealing functions are merged into integrated seal assemblies. The primary seal, secondary seal, and tertiary seal work together as a unified sealing system at the retort outlet, combining multiple protection functions in a single structural location. This merging reduces the total number of separate sealing surfaces compared to having independent seals for each inlet/outlet, thereby reducing potential leak paths while maintaining comprehensive gas flow control capability.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration significantly reduces contaminant ingress and maintains a consistent, clean atmosphere within the retort, enhancing the thermal processing performance and reducing the risk of contamination and process failures.

Implementation Method 1

A Peclet seal on the retort outlet prevents backflow of contaminants into the retort

Methodology Applied
Scientific EffectPeclet seal:

Implementation Method 2

Constructed from low-permeability materials, along with a limited number of inlets and outlets, to maintain a controlled atmosphere and reduce contaminant transport

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 3

a fore volume for gas cleansing

Methodology Applied
Scientific EffectGas cleansing:

Implementation Method 4

ensuring the retort's sealing surfaces experience temperature profiles identical to the objects being processed

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4137770A1Retort for improved thermal processing of sinterable objects
Publication Date: 2023.02.22 DESKTOP METAL INC
  • EP4137770A1 patent drawingFigure 1
  • EP4137770A1 patent drawingFigure 2
  • EP4137770A1 patent drawingFigure 3

AI summary

A retort for thermally processing sinterable objects including a retort body having an interior cavity configured to receive at least one part for sintering. The retort body includes a retort inlet, a fore volume, an inlet plenum, an outlet plenum and a retort outlet. The retort inlet is configured to be fluidly connected to a process gas inlet tube and receive a flow of process gas. The retort inlet is fluidly connected to the fore volume, the fore volume being configured to receive a cleansing object. The fore volume is fluidly connected to the inlet plenum, which is fluidly connected to the interior cavity, which is in turn fluidly connected to the outlet plenum. The outlet plenum is fluidly connected to the retort outlet which is configured to be fluidly connected to an effluent gas outlet tube via a Peclet sealing element.