Liquid Level Sensor Energy Control in Vacuuming Material Tanks
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Solution Overview
Problem
Self-heating liquid level sensors in vaporization systems for semiconductor manufacturing experience rapid temperature rises as the tank approaches a vacuum atmosphere, leading to reduced lifespan, deformation, and shifted detection values.
Innovation Solution
A monitoring and energy control system that adjusts the energy supplied to the liquid level sensor from normal to low-level energy when detection values reach predetermined limits, preventing rapid temperature increases and allowing continued monitoring to determine appropriate energy restoration times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If normal energy is supplied to the liquid level sensor for continuous monitoring, then the sensor can maintain detection function, but the temperature rises rapidly when the tank approaches vacuum atmosphere
Solution Approach 1:
The patent applies dynamic energy control by switching between normal energy and low-level energy supply modes based on real-time temperature monitoring. When the sensor temperature exceeds a predetermined threshold, the system dynamically reduces energy supply to prevent overheating, while restoring normal energy when temperature is within safe range, thus adapting to changing vacuum conditions.
Solution Approach 2:
The patent changes the energy supply parameter (from normal energy to low-level energy) based on the sensor's temperature detection values. This parameter adjustment allows the sensor to operate safely in vacuum atmosphere by reducing heat generation when temperature approaches critical levels, while maintaining detection functionality through continued low-level energy supply.
2Temperature
If energy supply is stopped when detection value reaches upper limit, then temperature rise is prevented, but temperature detection becomes impossible and restoration timing cannot be determined
Solution Approach 1:
Instead of completely stopping energy supply, the patent applies partial energy supply (low-level energy) when the temperature reaches the upper limit. This partial action maintains the sensor's temperature detection capability while sufficiently reducing heat generation to prevent rapid temperature rise, allowing continuous monitoring and determination of appropriate restoration timing.
3Productivity
If the sensor operates in vacuum atmosphere, then vaporization process continues, but the protective tube deforms and sensor lifespan decreases
Solution Approach 1:
The patent implements a feedback control mechanism where the sensor's temperature detection values are continuously monitored, and this information feeds back to the energy control portion. When temperature indicates approaching vacuum conditions, the system automatically reduces energy supply to prevent protective tube deformation, thereby extending sensor lifespan while allowing vaporization to continue.
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
Prevents rapid temperature rises, extending sensor lifespan, preventing deformation, and maintaining accurate detection values by controlling energy supply based on monitored values.
Implementation Method 1
this liquid level sensor is a self-heating type of sensor that generates heat when supplied with a constant current
Implementation Method 2
there is a decrease in the temperature being detected when a liquid material comes into contact with the heated sensor
Implementation Method 3
controls the energy supplied to the liquid level sensor in such a way that that this energy is low-level energy that is lower than the normal energy
Data Source
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AI summary
A rapid rise in the temperature of a liquid level sensor is prevented even in a case in which a vaporization of a liquid material advances so that the interior of a tank comes close to being a vacuum atmosphere. In a material supply system (100) that is equipped with a tank (211) containing a liquid material and with a liquid level sensor (213) that is provided inside the tank (211), and in which the liquid level sensor (213) is a self-heating type of sensor that, in a state in which the liquid level sensor (213) is generating heat as a result of being supplied with a predetermined normal energy, detects a liquid surface, there are provided a monitoring portion (44) that monitors a detection value obtained based on an output signal from the liquid level sensor (213), and an energy control portion (45) that, in a case in which the detection value monitored by the monitoring portion (44) reaches a predetermined upper limit value, performs control in such a way that the energy supplied to the liquid level sensor (213) is low-level energy that is lower than the normal energy.