Calibration Bath Tank Design for Rapid Fluid Cooling

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Solution Overview

Problem

Conventional calibration baths lack an efficient cooling mechanism, leading to prolonged cooling times, which can be hazardous and costly, especially when dealing with high-temperature fluids like silicone oils, and are limited by the temperature range of vapor compression refrigeration systems and thermo-electric modules.

Innovation Solution

A calibration device equipped with a microprocessor-controlled system that uses a fan motor and ambient air to rapidly cool fluids by adjusting the fan speed based on temperature differences, allowing for quick temperature regulation and extending the life of expensive silicone oils.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If conventional calibration baths rely on ambient conditions to cool the fluid, then the cooling process is simple and requires no additional components, but the cooling time becomes excessively long (several minutes to hours)

Engineering Contradiction:
Improvecooling timeVSAvoidcooling system complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The tank is divided into an inner tank and an outer tank, with the cooling system located in the annular space between them. This segmentation allows the cooling mechanism to be isolated from the fluid calibration space, enabling efficient heat removal without complicating the main calibration environment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary cooling system using a cooling element (such as a Peltier device or heat exchanger) placed in the annular space between the inner and outer tanks. This intermediary structure facilitates heat transfer from the calibration fluid to the ambient environment without direct contact between the cooling mechanism and the calibration fluid, thus reducing cooling time while maintaining system simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of time

If vapor compression refrigeration systems or external chillers are used to speed up cooling, then cooling time is reduced, but the high end temperature range is limited (e.g., limited to 170°C) and the systems become more complex

Engineering Contradiction:
Improvecooling timeVSAvoidmaximum operating temperature
Core Design Contradiction:
Loss of timeVSTemperature

Solution Approach 1:

The patent uses an intermediary cooling approach where the cooling element is positioned in the annular space between inner and outer tanks, acting as a thermal mediator. This allows the use of passive or low-temperature active cooling mechanisms that do not impose upper temperature limits on the calibration fluid, enabling operation above 170°C while still providing accelerated cooling capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The cooling function is extracted from the main calibration chamber and placed in the annular space between the inner and outer tanks. This separation allows the cooling system to operate independently without constraining the maximum temperature of the calibration fluid, thus removing the 170°C limitation associated with vapor compression systems.

Inventive Principle:
Principle #2Taking out (Extraction)

3Speed

If thermo-electric modules are used for cooling, then cooling speed is improved, but the maximum temperature range is limited due to module damage at high temperatures

Engineering Contradiction:
Improvecooling speedVSAvoidmaximum operating temperature
Core Design Contradiction:
SpeedVSTemperature

Solution Approach 1:

The tank structure is segmented into inner and outer tanks with a cooling channel in between, allowing thermo-electric modules to be positioned in the annular space rather than directly in contact with the calibration fluid. This segmentation protects the temperature-sensitive cooling modules from exposure to high temperatures, enabling their use in systems requiring high maximum operating temperatures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The annular space between the inner and outer tanks serves as an intermediary thermal zone, allowing thermo-electric cooling modules to operate in a temperature range they can withstand while still effectively cooling the calibration fluid in the inner tank. The outer tank acts as a thermal barrier protecting the modules from excessive heat.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Loss of time

If coils with compressed air or liquid circulation are used to speed up cooling, then cooling efficiency is improved, but the system becomes expensive and dangerous due to high pressures from boiling water

Engineering Contradiction:
Improvecooling timeVSAvoidhigh pressure and safety risks
Core Design Contradiction:
Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the cooling function from direct contact with the calibration fluid and places it in the annular space between inner and outer tanks. This extraction eliminates the need for high-pressure liquid circulation systems, as the cooling can be achieved through passive heat conduction or low-pressure air flow in the annular space, thereby removing the safety hazards associated with pressurized boiling water.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs simple, inexpensive cooling mechanisms such as passive heat dissipation through the outer tank walls or low-cost air circulation, replacing expensive and dangerous high-pressure liquid cooling systems. The cooling solution uses readily available materials and avoids the need for complex pressure containment systems.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 device significantly reduces cooling times, from hours to minutes, enhances safety by enabling quicker fluid cooling, and extends the lifespan of expensive fluids by maintaining them below their oxidation temperature, while operating effectively across a broader temperature range than conventional systems.

Implementation Method 1

a fan motor disposed within the chamber and arranged to drive air flow across a surface of the fluid

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

an insulating material disposed outside the chamber and surrounding an exterior surface of the chamber

Methodology Applied
Scientific EffectThermal Insulation: Thermal Insulation

Data Source

PatentEP3379220B1Device having tank shaped to produce flow direction and improve temperature stability and uniformity
Publication Date: 2021.03.03 FLUKE CORP
  • EP3379220B1 patent drawingFigure 1
  • EP3379220B1 patent drawingFigure 2
  • EP3379220B1 patent drawingFigure 3

AI summary

A device includes a tank, a motor, and a fluid propulsion device, for example, a propeller that is coupled to the motor. The tank includes a bottom wall and side walls. A first surface of a first side wall forms an obtuse angle with a surface of the bottom wall. The fluid propulsion device is disposed inside the tank opposite the first surface of the first side wall. A first surface of a second side wall forms an obtuse angle with the surface of the bottom wall. Rounded corners may be disposed within the tank where pairs of adjacent side walls meet the bottom wall. Rounded surfaces may be formed where the side walls meet the bottom wall. The structure of the tank enables the propeller to rapidly disperse a fluid throughout the tank.