Rocket Engine Screw Connector With Flexible Arm Sealing

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Solution Overview

Problem

Existing rocket engine screwed connections face challenges in maintaining seals under cryogenic to ambient temperature variations, withstanding vibrations, and requiring frequent maintenance due to material creep, while being expensive.

Innovation Solution

A threaded connection design featuring a flexible arm with lower stiffness than the joint portion, using a copper seal and annular projection for enhanced sealing, capable of absorbing stress and maintaining tightness across temperature and vibration changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If expensive sealed connections (RLSEP or VSEP) are used, then sealing performance under temperature and vibration conditions is improved, but manufacturing cost increases

Engineering Contradiction:
Improvesealing performanceVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The connection is divided into separate functional components: a rigid joining portion for sealing and a flexible arm for stress absorption. This segmentation allows each part to be optimized independently, achieving reliable sealing without the complex structure and high cost of RLSEP or VSEP connections.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the stiffness parameter of different components - the joining portion has high stiffness for sealing while the arm has low stiffness for flexibility. This parameter differentiation enables the connection to withstand temperature and vibration stresses while maintaining sealing, providing a cost-effective alternative to expensive sealed connections.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If flat gaskets are used, then manufacturing cost is reduced, but sealing reliability deteriorates due to material creep requiring frequent maintenance

Engineering Contradiction:
Improvemanufacturing costVSAvoidsealing reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The connection uses a composite structure combining a rigid joining portion (high stiffness) for sealing and a flexible arm (low stiffness) for stress absorption. This composite design eliminates the creep problem of flat gaskets while maintaining simple manufacturing, as the rigid portion maintains seal integrity under vibration and temperature changes without requiring frequent maintenance.

Inventive Principle:
Principle #40Composite materials

3Strength

If the arm has high stiffness, then structural strength is improved, but the connection cannot absorb thermal expansion stresses

Engineering Contradiction:
Improvestructural strengthVSAvoidtemperature range capability
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

Different parts of the connection have different stiffness properties tailored to their specific functions: the joining portion has high stiffness for structural strength and sealing, while the arm has low stiffness for flexibility and thermal stress absorption. This local quality differentiation allows the connection to operate reliably across wide temperature ranges from cryogenic to above ambient conditions.

Inventive Principle:
Principle #3Local quality

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

The connection provides reliable sealing across wide temperature ranges, withstands vibrations, and reduces manufacturing costs by simplifying production and eliminating the need for frequent maintenance.

Implementation Method 1

a portion of the seal portion is configured to plasticize when fluid passes through the conduit

Methodology Applied
Scientific EffectPlasticization: Plasticity

Implementation Method 2

the joining portion has a stiffness greater than that of the arm and the seal... the arm is deformed before the joint portion

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3985286B1Screw connector for a rocket engine
Publication Date: 2025.08.20 ARIANEGRP SAS
  • EP3985286B1 patent drawingFigure 1
  • EP3985286B1 patent drawingFigure 2~3D
  • EP3985286B1 patent drawingFigure 4A~4B

AI summary

Connection (10) of a pipe (50) to a support (20), comprising a joint (14) attached to the support (20), a joint portion (12) configured to cooperate with the joint (14) by clamping, and an arm (16) extending around the pipe (50) outside the pipe (50), connecting the pipe (50) to the joint portion (12), in which the joint portion (12) has a stiffness greater than that of the arm (16) and the joint (14).