Pump Pressure Relief Using Thermal Actuation for Overheat Prevention

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Solution Overview

Problem

Conventional pump systems in aerospace applications face challenges in preventing excessive fluid temperature buildup due to pump failures, which can lead to high-temperature reactions of fuel, and existing solutions are complex, slow to react, and may have latent failures undetectable before usage cycles.

Innovation Solution

A pump system incorporating a thermally-responsive material that senses over-temperature events and cooperates with a fluid-operated control to decrease pump output pressure, ensuring no latent failures with a dormancy period greater than one usage cycle, and maintaining operational functionality after the material reaches its activation temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional temperature sensors and electrical solenoids are used for overheat prevention, then temperature monitoring capability is improved, but system complexity increases and response speed decreases

Engineering Contradiction:
Improvetemperature monitoring capabilityVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces electrical temperature sensors and solenoid controls with a purely mechanical thermal expansion mechanism. The thermal element expands directly in response to temperature increases, mechanically actuating the pressure relief valve without requiring electrical components, software, or complex sensing systems. This mechanical substitution resolves the contradiction by eliminating the complexity and slow response inherent in electrical sensing and control systems.

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

Solution Approach 2:

The thermal element performs both sensing and actuation functions simultaneously through its own thermal expansion. The element that detects temperature rise is the same element that directly opens the pressure relief valve, eliminating the need for separate sensors, signal processing circuits, and control actuators. This self-service approach dramatically simplifies the system while maintaining fast response to overheating conditions.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If redundant temperature sensors and software controls are implemented, then temperature detection accuracy is improved, but response time to rapidly rising temperatures deteriorates

Engineering Contradiction:
Improvetemperature detection accuracyVSAvoidresponse time
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent replaces electrical sensing and software processing with direct mechanical response. The thermal element's expansion is instantaneous and proportional to temperature rise, providing both accurate temperature detection and immediate response without the delays inherent in electrical signal transmission, software processing, and actuator response times.

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

Solution Approach 2:

The thermal element continuously monitors temperature and provides continuous mechanical actuation of the pressure relief valve. As temperature rises, the element continuously expands, maintaining proportional pressure relief throughout the overheating event. This continuous mechanical action eliminates the discrete sampling and processing delays associated with electrical sensor systems.

Inventive Principle:
Principle #20Continuity of useful action

3Speed

If mechanical pressure reduction mechanisms are used, then response speed to temperature changes is improved, but ability to detect latent failures before usage cycles deteriorates

Engineering Contradiction:
Improveresponse speedVSAvoiddetection of latent failures
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The thermal element is pre-positioned and pre-loaded in such a way that any latent failure affecting its thermal expansion capability will manifest as an abnormal condition detectable before the next usage cycle. The element's mechanical connection to the pressure relief valve allows inspection of its position and functionality prior to operation, enabling detection of latent failures while maintaining fast response during actual overheating events.

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If electrical solenoids and software control are used to reduce pump pressure, then precision of pressure control is improved, but system simplicity and reliability deteriorate

Engineering Contradiction:
Improvepressure control precisionVSAvoidsystem simplicity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces electrical solenoid-based pressure control with a mechanical thermal expansion mechanism. The thermal element's expansion directly modulates the pressure relief valve opening, providing precise pressure control through pure mechanical means. This eliminates electrical components, software control logic, and associated complexity while maintaining reliable pressure regulation in response to overheating.

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

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 effectively prevents excessive fluid temperature buildup by quickly responding to overheating events, reducing pump output pressure, and ensuring the system remains operational, thereby preventing high-temperature reactions and latent failures, with improved reliability and detection capabilities.

Implementation Method 1

the thermally-responsive material is in thermal communication with the fluid flowing through the pump system for effecting a change in temperature of the thermally-responsive material

Methodology Applied
Scientific EffectThermal communication: Conduction (thermal)

Implementation Method 2

the thermally-responsive material is configured to have an activation temperature that causes a transformation of the material

Methodology Applied
Scientific EffectPhase transformation: Phase Change

Data Source

PatentEP4031767B1Pump system with over-temperature prevention
Publication Date: 2023.11.01 PARKER HANNIFIN CORP
  • EP4031767B1 patent drawingFigure 1
  • EP4031767B1 patent drawingFigure 2
  • EP4031767B1 patent drawingFigure 3

AI summary

A pump system including a prevention mechanism for preventing excessive fluid temperature buildup of system fluid. The overheat prevention mechanism includes a thermally-responsive control component (130) made with a thermally-responsive material. The thermally-responsive control component is located in the pump system (112) such that the thermally-responsive material is in thermal communication with the system fluid for effecting a change in temperature of the thermally-responsive material. The thermally-responsive material is configured to have an activation temperature that is a predefined amount less than a maximum operating temperature of the system fluid. The thermally-responsive control component is configured to cooperate with a pump control mechanism in the system to decrease pump output pressure in response to the thermally-responsive material being heated by the fluid to a temperature that is equal to or greater than the activation temperature of the thermally-responsive material.