Vacuum Gauge Reference Chamber Thermal Isolation
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Solution Overview
Problem
Existing vacuum gauges face accuracy degradation due to large pressure changes and temperature fluctuations, which cause deformation of the diaphragm and supporting structures, leading to errors in pressure measurement.
Innovation Solution
A vacuum gauge design incorporating a reference pressure chamber set at a high vacuum to reduce temperature influences, combined with an introduction tube made of low heat conductivity materials to minimize heat transfer, and an inner structure that reinforces the piezoelectric element to ensure accurate pressure measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the diaphragm and piezoelectric element are directly exposed to ambient temperature changes, then the device structure remains simple, but measurement accuracy degrades due to thermal deformation
Solution Approach 1:
The device is divided into two separate chambers: a pressure introduction chamber for the gas to be measured and a reference pressure chamber maintained at high vacuum. This segmentation isolates the piezoelectric element from ambient temperature fluctuations while allowing pressure measurement, thereby improving measurement accuracy without excessive structural complexity
Solution Approach 2:
The reference pressure chamber is maintained at a high vacuum state (lower than the pressure lower limit of the gas to be measured), creating an inert thermal environment that minimizes heat transfer to the piezoelectric element. This vacuum insulation layer reduces thermal deformation and improves measurement stability
2Measurement precision
If the reference pressure chamber is set at high vacuum, then temperature influence is reduced, but the pressure in the reference chamber may affect measurement accuracy
Solution Approach 1:
The reference pressure chamber is set to a specific pressure parameter (high vacuum state lower than the pressure lower limit of the gas to be measured) to optimize thermal insulation while ensuring the reference pressure does not interfere with measurements. This parameter optimization allows the vacuum to function as both a reference and a thermal barrier
Solution Approach 2:
The reference pressure chamber acts as an intermediary between the pressure introduction chamber and the external environment. It provides a stable thermal reference while isolating the measurement system from ambient temperature variations, thereby improving both accuracy and reliability
3Temperature
If the introduction tube uses high heat conductivity material, then heat transfer efficiency is improved, but temperature changes affect the piezoelectric element more strongly
Solution Approach 1:
The introduction tube is designed with non-uniform properties: the portion inside the airtight container uses low heat conductivity material to minimize heat transfer to the piezoelectric element, while the external portion can use different materials. This local differentiation optimizes thermal insulation where needed without compromising overall functionality
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 enables accurate pressure measurement with high accuracy (0.1% or less) and real-time temperature correction, effectively suppressing the impact of temperature changes and maintaining measurement precision across varying conditions.
Implementation Method 1
a piezoelectric element 50 having one end coupled to the diaphragm 40, and to be displaced along with the diaphragm
Implementation Method 2
a high vacuum of the reference pressure chamber is made to function also as a vacuum heat-insulating portion, which suppresses convection heat transfer so as to reduce an influence due to a temperature change
Implementation Method 3
solid heat conduction is suppressed by the introduction tube that has at least one of the first portion and the second portion made of a material having a low heat conductivity of 2 to 10 W/m·K
Data Source
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AI summary
A vacuum gauge includes an introduction tube 320, a diaphragm 40 displaced by a gas to be measured that is introduced from the introduction tube, a piezoelectric element 50 that has one end coupled to the diaphragm and is displaced along with the diaphragm, an inner structure 310 to which a circumferential edge of the diaphragm and the other end of the piezoelectric element are secured, the inner structure being coupled to the introduction tube, and an airtight container 300 to airtightly enclose the introduction tube and the inner structure. The inner structure, the introduction tube, and the diaphragm airtightly partition a space in the airtight container into a pressure introduction chamber 130 to which the gas to be measured is introduced on one surface side of the diaphragm, and a reference pressure chamber 120 on the other surface side of the diaphragm. The reference pressure chamber is set at a high vacuum that is lower than the pressure lower limit of the gas to be measured.