Horizontal Liquid Level Indicator for Semiconductor Vaporization Feeders
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Solution Overview
Problem
Conventional thermal liquid level detectors in liquid raw material vaporization feeders for semiconductor manufacturing are slow in detection and dependent on flow rate, making accurate phase transition detection challenging.
Innovation Solution
A liquid level indicator with horizontally disposed protection tubes housing resistance temperature detectors, where a heating current and a measurement current are alternately passed through the detectors to compare resistances and determine the phase, reducing detection time and flow rate dependence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a conventional thermal liquid level detector uses vertically inserted protection tubes with resistance temperature detectors, then the device can detect liquid level, but the detection time is long and the detection response is slow
Solution Approach 1:
The invention changes the installation orientation of the protection tube from vertical to horizontal. This dimensional change allows the resistance temperature detector to be fully submerged in the liquid phase when liquid level is sufficient, enabling rapid heat dissipation and quick phase transition detection, thereby significantly reducing detection time while maintaining reliability
2Productivity
If a conventional thermal liquid level detector passes current through resistance temperature detectors, then the device can measure temperature and detect phase, but the detection time is dependent on flow rate
Solution Approach 1:
By installing the protection tube horizontally, the invention ensures that the resistance temperature detector is always in full contact with the liquid phase during normal operation. This eliminates the flow rate dependence because the detector's thermal environment is determined by its horizontal submersion position rather than by liquid flow dynamics, making detection speed independent of flow rate variations
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 significantly shortens detection time and eliminates flow rate dependence on phase transition detection, enabling more accurate and efficient liquid level control in vaporization feeders.
Implementation Method 1
a relatively large constant current I1 (heating current) is passed through one resistance temperature detector R1 so that the resistance temperature detector R1 is maintained at a temperature higher than the ambient temperature by self-heating
Implementation Method 2
the heat dissipation constant in the case where the resistance temperature detector is in the liquid phase L is larger than the heat dissipation constant in the case where it is in the gas phase V
Data Source
AI summary
To provide a liquid level indicator and a liquid raw material vaporization feeder, in which the time to detect a switch from the liquid phase to the gas phase has reduced flow rate dependence, and also the detection time can be shortened. The present invention includes a chamber 2 that stores a liquid raw material, at least one protection tube 3 housing a resistance temperature detector for detecting the liquid level L1 in the chamber 2, and a flow controller 4 that controls the flow rate of the gas flowing out from the chamber 2 and feeds the same. The protection tube 3 is horizontally inserted into a sidewall 2a of the chamber 2 and fixed thereto.