Passive Flow Rate Adapter for Temperature-Driven Liquid Cooling

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Solution Overview

Problem

Conventional liquid cooling solutions for IT equipment require complex feedback loops, additional control boards, sensors, and motors to adjust coolant flow rates based on temperature, leading to high costs and reliability issues.

Innovation Solution

A passive, on-demand flow rate adapter that uses a temperature gradient to mechanically control the flow rate of a working fluid through chambers, leveraging a flexible diaphragm and gate to adjust flow rates based on the thermal load of IT equipment, eliminating the need for active control equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional feedback loops with sensors and motors are used to control flow rate, then flow rate adjustment capability is improved, but device complexity and cost increase

Engineering Contradiction:

Improveflow rate adjustment capabilityVSAvoiddevice complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The flow adapter automatically adjusts flow rate based on temperature differential without external control signals. The thermally-responsive material changes viscosity or phase in response to temperature, causing the adapter to self-regulate flow rate passively, eliminating sensors, motors, and control boards

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces active mechanical control systems (motors, valves actuated by control signals) with a passive thermal-mechanical system. The thermally-responsive material undergoes physical changes in response to temperature, mechanically adjusting flow rate without electrical actuators or control electronics

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If conventional control boards and sensors are added for temperature-based flow control, then cooling precision is improved, but reliability decreases

Engineering Contradiction:

Improvetemperature-based flow control precisionVSAvoidsystem reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The flow adapter uses the temperature differential itself as the control signal, eliminating the need for external temperature sensors. The thermally-responsive material directly responds to temperature changes, making the system inherently more reliable by removing failure-prone electronic components

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent extracts and eliminates the sensor and control board components from the system. By using the temperature differential directly to drive the thermally-responsive material, the design removes the intermediate measurement and control electronics that reduce reliability

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of operation

If active control equipment is used for flow rate adjustment, then cooling control capability is improved, but power consumption increases

Engineering Contradiction:

Improvecooling control capabilityVSAvoidpower consumption

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The flow adapter is entirely passive and requires no external power source. It uses the natural temperature differential in the coolant flow to drive the thermally-responsive material, which automatically adjusts flow rate without consuming electrical energy

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces electrically-powered actuators and control systems with a passive thermal-mechanical system. The thermally-responsive material undergoes physical changes driven by temperature, mechanically adjusting flow rate without electrical energy input

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 flow rate adapter optimizes coolant flow rates for individual IT equipment, simplifies manifold design, enhances assembly efficiency, and reduces power consumption while maintaining reliability, allowing mixed IT equipment to be cooled in a single rack.

Implementation Method 1

a gate movable within the fourth chamber based at least in part on a temperature gradient between working fluid flowing through the first and fourth chambers

Methodology Applied

Scientific EffectTemperature gradient: Temperature Gradient

Implementation Method 2

a flexible diaphragm separating, and fluidly isolating, the second and third chambers

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS12474725B2On-demand flow rate adapter for flow rate adjustment in liquid cooling solutions

Publication Date: 2025.11.18 CISCO TECHNOLOGY INC

AI summary

A flow rate adapter includes an enclosure defining an interior, a first partition separating the interior into first and second chambers, a second partition separating the interior into third and fourth chambers, and a flexible diaphragm separating the second and third chambers. Each chamber is fluidly isolated from one another. The second and third chambers are positioned between the first and fourth chambers with the second chamber being positioned adjacent to the first chamber and the third chamber being positioned adjacent to the fourth chamber. The second and third chambers are positioned adjacent to one another. The flow rate adapter includes a gate coupled with the flexible diaphragm. A temperature gradient between working fluid flowing through the first and fourth chambers causes the flexible diaphragm to flex, which moves the gate within the fourth chamber to control the flow rate of the working fluid.