Backup Selector Pump Layout for VDP Reliability

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Solution Overview

Problem

Existing variable displacement pump systems fail to address the reliability and efficiency of centrifugal pumps in applications such as centrifugal pumps, so when the centrifugal pumps are not considered to be the most reliable type of pump, they are not suitable for single engine aircraft.

Innovation Solution

A system with a variable displacement pump (VDP) and a backup pump configuration, including a backup selector, a second pump, and a controller to switch between normal and backup modes, ensuring reliability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a variable displacement pump (VDP) is used to minimize horsepower required for fuel pumping, then energy efficiency is improved, but reliability deteriorates due to higher part count

Engineering Contradiction:
Improvehorsepower required for fuel pumpingVSAvoidpump reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The pump system is segmented into two independent pumps: a VDP (first pump) for normal operation and a centrifugal pump (second pump) for backup. This segmentation allows each pump to be optimized for its specific function while maintaining overall system reliability through redundancy

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A backup centrifugal pump is provided in advance as a redundant component. The backup pump remains standby and is activated only upon failure of the primary VDP, providing beforehand cushioning against potential failures and ensuring continuous operation

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If a backup pump system is added to improve reliability, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvepump system reliabilityVSAvoidpump system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system employs self-service mechanisms through automatic failure detection and backup activation. The backup selector valve automatically switches between the VDP and centrifugal pump based on system conditions, eliminating the need for complex manual control systems

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The backup selector valve merges the output lines of both the VDP and centrifugal pump into a single common outlet. This consolidation allows two pumps to operate independently while sharing common infrastructure, reducing overall system complexity

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 system provides backup capabilities for pump redundancy, reducing part count and envelope size, while maintaining reliability and efficiency, enabling VDPs in applications where they were previously unsuitable.

Implementation Method 1

An ejector connects to the auxiliary outlet between the second pump and the SVC

Methodology Applied
Scientific EffectVenturi effect: Venturi Effect

Implementation Method 2

a check valve (CV) is included in the backup line, wherein the CV is configured to block flow through the backup line in the normal mode and to allow flow through the backup line in the backup mode

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentEP4390099B1Variable displacement pump with back-up
Publication Date: 2025.12.10 HAMILTON SUNDSTRAND CORP
  • EP4390099B1 patent drawingFigure 1
  • EP4390099B1 patent drawingFigure 2

AI summary

A system includes a variable displacement pump (VDP) (102) with a pump inlet (104) and a pump outlet (106). The VDP is configured to receive a flow at the pump inlet at a first pressure and to outlet a flow from the pump outlet at a second pressure elevated relative to the first pressure. A second pump (200) is in fluid communication to receive flow at the pump inlet at the first pressure and to outlet flow from an auxiliary outlet (202). A backup selector (204) is in fluid communication with the pump outlet and with the auxiliary outlet. The backup selector is configured to operate in a normal mode to supply the the pump outlet from the VDP and to supply the auxiliary outlet from the second pump. The backup selector is configured to switch to a backup mode to supply the pump outlet from the second pump upon failure of the VDP.