Combined Relief and Bypass Valve for Variable Displacement Pumps

Solution Overview

Problem

Conventional fuel system architectures for variable displacement pumps in aerospace applications require a large number of control valves, leading to increased complexity and weight, which is inefficient and cumbersome.

Innovation Solution

A combined high pressure relief and windmill bypass valve system that integrates a single relief valve with dual functionality, allowing it to switch between high pressure relief and windmill bypass modes based on pressure thresholds, reducing the need for multiple valves and simplifying the system architecture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple separate valves (high pressure relief valve and windmill bypass valve) are used, then the system can provide both high pressure relief and windmill bypass functions, but the valve count increases leading to increased complexity and weight

Engineering Contradiction:

Improvevalve functionalityVSAvoidvalve count

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines a high pressure relief valve and a windmill bypass valve into a single integrated valve assembly. The valve body contains both a relief valve portion with relief valve seat and a bypass valve portion with bypass valve seat, allowing both functions to be performed by one component rather than requiring separate valves.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single valve assembly is designed to perform multiple functions: it can operate as a high pressure relief valve to prevent overpressurization, and as a windmill bypass valve to allow free rotation of the pump impeller during shutdown conditions. The valve mechanism integrates both relief and bypass capabilities in one universal component.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple separate valves are used, then both high pressure relief and windmill bypass functions are provided, but the system weight increases

Engineering Contradiction:

Improvevalve functionalityVSAvoidvalve system weight

Core Design Contradiction:

Adaptability or versatilityVSWeight of stationary object

Solution Approach 1:

The patent combines a high pressure relief valve and a windmill bypass valve into a single integrated valve assembly. The valve body contains both a relief valve portion with relief valve seat and a bypass valve portion with bypass valve seat, allowing both functions to be performed by one component rather than requiring separate valves.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If multiple separate valves with valve sets, springs, and closures are used, then the required functions are achieved, but manufacturing complexity and assembly requirements increase

Engineering Contradiction:

Improvevalve functionalityVSAvoidassembly complexity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent combines a high pressure relief valve and a windmill bypass valve into a single integrated valve assembly. The valve body contains both a relief valve portion with relief valve seat and a bypass valve portion with bypass valve seat, allowing both functions to be performed by one component rather than requiring separate valves.

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 integrated valve system reduces valve count, complexity, and weight, while enhancing pumping efficiency and reducing fuel control leakages by eliminating the need for separate high pressure relief and windmill bypass valves.

Implementation Method 1

The valve sleeve is configured and adapted to translate axially along a longitudinal RV axis depending on the pressure in at least one of the RV inlet port or the control pressure port

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentEP4495425B1Combined high pressure relief and bypass valves

Publication Date: 2026.04.01 HAMILTON SUNDSTRAND CORP

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AI summary

A system includes a variable displacement pump (VDP) in fluid communication with an inlet line and with an outlet line. The VDP includes a variable displacement mechanism configured to vary pressure to the outlet line. The system includes a relief valve (RV) having a control pressure port (108) and an RV inlet port (110) in fluid communication with the outlet line and an RV outlet in fluid communication with a bypass line. The system includes an actuator operatively connected to the control pressure port (108) of the RV to change function of the RV between a first function and a second function. The first function is a high pressure relief valve function and the second function is as a wind milling bypass function.