Monolithic Damper Check Valve for Reverse Oil Flow Resistance

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Solution Overview

Problem

Gas turbine engines face issues with oil backflow into the lubrication system due to vibration-induced pressure changes, leading to reduced effectiveness of oil film dampers and potential damage to lubrication components, which traditional mechanical check valves cannot adequately address due to wear and limited lifespan.

Innovation Solution

A monolithic, unitary damper check valve with a converging-diverging fluid channel design, featuring a Venturi shape and an annular gap, inhibits reverse oil flow without moving parts, ensuring easier mass flow in the standard direction and causing high pressure losses during reverse flow, thus preventing oil backflow effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mechanical check valve is used to prevent oil backflow, then oil backflow is reduced, but the valve contains moving parts that are subject to wear and have limited lifespan

Engineering Contradiction:
Improveoil backflow preventionVSAvoidvalve lifespan
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The invention extracts and eliminates the moving parts from the check valve design. Instead of using a mechanical valve with moving components, the patent employs a fixed geometry converging-diverging channel that uses fluid dynamic effects to achieve check valve functionality without any moving parts, thereby resolving the contradiction between backflow prevention and component lifespan

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical system (moving parts) with a fluid dynamic system. The converging-diverging channel utilizes the Venturi effect and pressure differential mechanisms to prevent backflow, substituting mechanical action with fluid dynamic principles, which eliminates wear and extends operational life

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If traditional mechanical check valves are used, then oil backflow is prevented, but the moving parts are subject to wear and require maintenance

Engineering Contradiction:
Improvebackflow preventionVSAvoidmaintenance requirements
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The invention removes moving parts entirely from the check valve design, replacing them with a fixed geometry converging-diverging channel. This extraction of moving components eliminates wear and the associated maintenance requirements while preserving the backflow prevention function

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention employs a simple, fixed-geometry channel structure that has no moving parts to wear out. The design is inherently maintenance-free and can be easily replaced if needed, effectively treating the valve as a disposable or long-life component that eliminates ongoing maintenance burden

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If a monolithic passive check valve with converging-divergent channel is used, then backflow is reduced without moving parts, but the device complexity increases

Engineering Contradiction:
Improvebackflow prevention without moving partsVSAvoidvalve structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the check valve function into a single monolithic passive structure with a converging-diverging channel. By combining all necessary geometric features into one integrated component with no moving parts, the design achieves backflow prevention while actually simplifying the overall device complexity compared to mechanical valve assemblies

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

The solution significantly reduces reverse oil flow rates, maintaining the effectiveness of the oil film damper and preventing damage to lubrication components, while eliminating the need for movable parts, thus enhancing the operational stability and longevity of the gas turbine engine.

Implementation Method 1

A monolithic, unitary damper check valve with a converging-diverging fluid channel design, featuring a Venturi shape... causes high pressure losses during reverse flow

Methodology Applied
Scientific EffectVenturi effect: Venturi Effect

Data Source

PatentEP3421738B1Damper check valve
Publication Date: 2021.03.31 RTX CORP
  • EP3421738B1 patent drawingFigure 1
  • EP3421738B1 patent drawingFigure 2

AI summary

The present invention relates to a gas turbine engine (10) including a bearing compartment assembly (58). The bearing compartment assembly (58) includes a fluid pump (62), a compartment, a fluid line (63) between the fluid pump (62) and the compartment, and a damper check valve (60) located in the fluid line (63). The damper check valve (60) is a unitary, monolithic component that is configured to restrict a reverse flow from the compartment to the fluid pump (62) more than the damper check valve (60) restricts a standard flow from the fluid pump (62) to the compartment. For this purpose, the damper check valve (60) comprises a converging portion (68), a diverging portion (70) and a constriction (82) arranged between the converging and diverging portions (68, 70). Due to this specific shape, the check valve does not need any moving elements reducing the risk of wear, thus, increasing life-span.