Precision Degassing and Charging System for Phase-Change Thermal Devices
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Solution Overview
Problem
Miniature phase-change thermal devices face challenges in precisely controlling the volume of working fluid and achieving accurate vacuum levels, leading to inconsistent performance, particularly in thermal switch devices where non-condensable gases affect switching temperatures.
Innovation Solution
A system and method that integrates degassing and charging processes using a flask, valves, and a vacuum pump to control the precise injection of working fluid into phase-change thermal devices, ensuring accurate vacuum levels and charging amounts, utilizing a fluid injection device like a syringe to inject the fluid with high precision and adjust internal pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional injection methods are used to charge miniature phase-change thermal devices, then the charging process is simple, but the volume control precision of working fluid is poor
Solution Approach 1:
The charging system is segmented into multiple independent components: a flask for working fluid storage, a fluid injection device for precise delivery, and multiple valves for process control. This segmentation allows each component to perform its function with high precision while maintaining overall system manageability.
Solution Approach 2:
A fluid injection device acts as an intermediary between the working fluid reservoir and the phase-change thermal device. This intermediary component enables precise volume control by metering the fluid delivery, solving the contradiction between simplicity and precision.
2Manufacturing precision
If non-condensable gases are present in the chamber, then the device structure remains simple, but the switching temperature becomes uncontrollable
Solution Approach 1:
The system performs preliminary degassing of the working fluid in the flask before charging the phase-change thermal device. This preliminary action removes non-condensable gases from the working fluid, preventing them from contaminating the device chamber and affecting switching temperature control.
Solution Approach 2:
The vacuum process is integrated continuously with the charging process. The system maintains vacuum conditions throughout the working fluid transfer and injection operations, ensuring continuous removal of non-condensable gases and preventing their accumulation in the device chamber.
3Reliability
If working fluid volume is not precisely controlled, then the charging process is faster, but the device performance becomes inconsistent
Solution Approach 1:
The fluid injection device incorporates feedback mechanisms to monitor and control the volume of working fluid injected into the phase-change thermal device. This feedback control ensures precise volume delivery, guaranteeing consistent device performance while maintaining efficient charging speeds.
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
Enables precise charging of phase-change thermal devices with an accuracy of ±1% for volumes up to 1 ml, ±5% for 0.07-0.2 ml, and ±10% for 0.02-0.06 ml, with adjustable internal pressure accuracy of ±0.01 kPa, improving device performance and reliability.
Implementation Method 1
a heating element thermally coupled to the flask and operable to heat the working fluid within the flask
Implementation Method 2
a vacuum pump fluidly coupled to the third valve
Implementation Method 3
A phase-change thermal device is a device that is filled (i.e., charged) with a working fluid that changes to a vapor in response to thermal energy
Data Source
AI summary
Systems and methods for degassing and charging phase-change thermal devices are disclosed. In one embodiment, a system includes a flask, a first shut-off valve fluidly coupled to an outlet of the flask, and a first valve fluidly coupled to the first shut-off valve by a fluid line. The system further includes a second valve fluidly coupled to the first valve, wherein the second valve is operable to be fluidly coupled to the phase-change thermal device, a second shut-off valve fluidly coupled to the second valve, a third valve fluidly coupled to the first valve, a vacuum pump fluidly coupled to the third valve, and a fluid injection device fluidly coupled to the fluid line between the first valve and the first shut-off valve. The fluid injection device draws the working fluid from the flask and injects a desired amount into the phase-change thermal device.