Liquid Submersion Cooling With Gravity Return Manifolds

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Solution Overview

Problem

Existing liquid submersion cooling systems for electronic devices rely heavily on pump pressure for both liquid delivery and return, which can be costly and complex, and do not efficiently manage cooling liquid levels and flow rates.

Innovation Solution

A system utilizing gravity return manifolds and dielectric cooling liquids, where cooling liquid is returned to a reservoir via gravity, with pump pressure only used for delivery, and controlled by weirs to maintain optimal liquid levels and flow rates for efficient cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pump pressure is used for both liquid delivery and return in existing liquid submersion cooling systems, then the cooling liquid can be circulated through electronic devices, but the system complexity and cost increase

Engineering Contradiction:
Improvecooling liquid circulationVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the cooling liquid circulation system into two separate functional segments: a delivery system using pump pressure to supply cooling liquid to electronic devices, and a return system using gravity and weir structures to return cooling liquid to the reservoir. This segmentation eliminates the need for return pumps, reducing system complexity while maintaining reliable circulation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces the mechanical pump-based return system with a gravity-based passive return system. By substituting the mechanical pumping mechanism with gravitational force and hydraulic structures (weirs), the system reduces mechanical complexity and moving parts while maintaining effective cooling liquid circulation

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

2Reliability

If pump pressure is used for both liquid delivery and return, then cooling liquid can be circulated, but the system cost increases

Engineering Contradiction:
Improvecooling liquid circulationVSAvoidsystem cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the return pump component from the cooling liquid circulation system, eliminating the need for expensive pumping equipment on the return side. By taking out this mechanical component and replacing it with passive gravity-based structures, the system cost is reduced while maintaining reliable circulation through the electronic devices

Inventive Principle:
Principle #2Taking out (Extraction)

3Temperature

If conventional cooling systems are used, then electronic devices can be cooled, but liquid level and flow rate management is inefficient

Engineering Contradiction:
Improveelectronic device coolingVSAvoidliquid level and flow rate management
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The patent implements self-regulating weir structures that automatically maintain optimal liquid levels and control flow rates through passive hydraulic principles. The weirs self-adjust the cooling liquid flow based on液位 height without requiring external control systems, making the system easier to operate while maintaining effective cooling of electronic devices

Inventive Principle:
Principle #25Self-service

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

This approach reduces system complexity and cost while enhancing cooling efficiency by minimizing the need for pumps on the return side and optimizing liquid flow, maintaining superior cooling performance compared to air cooling.

Implementation Method 1

a returning supply flow of the cooling liquid may also be directed onto one or more of the heat generating electronic components

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

dielectric cooling liquid is in the interior space with the dielectric cooling liquid submerging and in direct contact with the heat generating electronic components

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

gravity can be used to return the cooling liquid to a reservoir via a cooling liquid gravity return manifold

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3685642B1Liquid submersion cooled electronic systems and devices
Publication Date: 2025.09.03 LIQUIDCOOL SOLUTIONS INC
  • EP3685642B1 patent drawingFigure 1
  • EP3685642B1 patent drawingFigure 2
  • EP3685642B1 patent drawingFigure 3

AI summary

Liquid submersion cooling systems are described that use a cooling liquid, for example a dielectric cooling liquid, to submersion cool an array of electronic devices. In some embodiments described herein, rather than using pump pressure to return the cooling liquid back to a cooling liquid reservoir, gravity can be used to return the cooling liquid to a reservoir via a cooling liquid gravity return manifold, and a pump can only be used on the liquid supply side to deliver the cooling liquid to each electronic device.