Pump Bypass Flow Split for Minimum Flow and Overheat Control

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Solution Overview

Problem

Conventional fluid pump systems in aircraft fuel systems face challenges in managing fuel capacity and heat rejection, leading to pump overheating and inefficiencies due to complex valve arrangements that increase weight and size.

Innovation Solution

A controllable pump system with a flow split mechanism, including a bypass line and a flow sense valve, utilizes sensors and actuators to maintain a minimum flow rate, preventing overheating while optimizing output flow through a flow module and shut-off valve.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional valve arrangements are used to control flow, then flow control capability is achieved, but system weight and size increase

Engineering Contradiction:
Improveflow control capabilityVSAvoidsystem weight
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The patent extracts the flow control function from complex mechanical valve arrangements and implements it through a simplified system using a flow divider and electronic control. The flow divider separates total pump flow into measured and unused portions, with electronic sensors and controllers replacing heavy mechanical valves to achieve flow control capability while reducing system weight.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces conventional mechanical valve arrangements with an electronic control system comprising flow sensors, position sensors, and electronic controllers. This substitution eliminates complex mechanical linkages and heavy valve components while maintaining flow control capability through electronic actuation of pump displacement.

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

2Ease of operation

If complex valve arrangements are used to control flow, then flow control capability is achieved, but system size increases

Engineering Contradiction:
Improveflow control capabilityVSAvoidsystem size
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The patent extracts the flow control function from complex mechanical valve arrangements and implements it through a simplified system using a flow divider and electronic control. The flow divider separates total pump flow into measured and unused portions, with electronic sensors and controllers replacing heavy mechanical valves to achieve flow control capability while reducing system size.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs multi-functional components where the flow divider serves both flow control and flow measurement functions, and the electronic control system integrates multiple control tasks (flow regulation, temperature management, efficiency optimization) into a single compact unit, reducing overall system size compared to dedicated separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If pump flow is reduced to match demand, then fuel capacity is optimized, but pump temperature increases causing overheating

Engineering Contradiction:
Improvefuel capacityVSAvoidpump temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent implements feedback control using flow sensors and temperature sensors that continuously monitor system conditions. The electronic controller adjusts pump displacement and bypass flow based on real-time feedback to maintain optimal operating temperature while matching flow output to actual demand, preventing overheating during low-flow conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses variable displacement pump technology that dynamically adjusts pump output based on actual system demand. The electronic control system continuously modifies pump displacement to optimize the balance between maintaining sufficient flow for cooling and matching demand to maximize fuel capacity, enabling adaptive temperature management.

Inventive Principle:
Principle #15Dynamics

4Temperature

If minimum flow rate is maintained to prevent overheating, then pump temperature is controlled, but output flow efficiency decreases

Engineering Contradiction:
Improvepump temperatureVSAvoidoutput flow efficiency
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The patent segments the total pump flow into two distinct paths: a measured flow portion that goes to the output and an unused flow portion that is bypassed. This segmentation allows the system to maintain minimum flow through the pump for cooling while directing only the necessary amount to the output, improving overall flow efficiency by eliminating unnecessary flow through complex valve arrangements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a flow divider as an intermediary component that separates total pump flow into measured and unused portions. This intermediary enables precise control of output flow while maintaining adequate flow for pump cooling, improving efficiency by eliminating the need for complex valve arrangements that would otherwise be required to achieve the same flow control.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 effectively maintains pump temperature and output flow, reducing the risk of overheating and simplifying the system design by eliminating complex valves, thereby reducing weight and size.

Implementation Method 1

The flow split system can include a flow sense valve (FSV) comprising a piston. The piston can be biased (e.g., with a spring) against pressure on the bypass line such that the bypass flow is configured to move the piston.

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

The piston position sensor can be a linear variable differential transformer (LVDT), for example.

Methodology Applied
Scientific EffectLinear variable differential transformer:

Implementation Method 3

The piston can be biased (e.g., with a spring) against pressure on the bypass line such that the bypass flow is configured to move the piston.

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP4467800B1Fluid pump systems
Publication Date: 2026.04.01 HAMILTON SUNDSTRAND CORP
  • EP4467800B1 patent drawingFigure 1

AI summary

A fluid pump system can include a controllable pump (101) configured to generate a pump flow through the controllable pump and to output an output flow to an output line (103). The fluid pump system can include a flow split system (105) configured to be in fluid communication with the controllable pump in a bypass state such that the flow split system is configured to divert a portion of the pump flow to maintain a desired output flow to the output line but to also allow the controllable pump to maintain a minimum pump flow through the controllable pump to maintain pump temperature below a high temperature threshold.