Molecular Pump Condensation Prevention via Relative Humidity Control
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Solution Overview
Problem
Existing molecular pumps face challenges in preventing condensation formation inside the control unit, leading to potential malfunctions and inefficient operation due to the limitations of condensation sensors and humidity detectors in high humidity environments.
Innovation Solution
A molecular pump design that incorporates a humidity detecting portion and temperature detecting portions strategically placed within the control unit to predict and prevent condensation by controlling the cooling unit's operation based on relative humidity calculations, ensuring continuous and accurate humidity monitoring and preventing condensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a condensation sensor is used to detect condensation inside the control unit, then condensation can be detected, but condensation has already formed by the time it is detected, making prevention ineffective
Solution Approach 1:
The humidity sensor detects humidity levels before condensation forms, allowing the cooling unit to be adjusted in advance to prevent condensation. This preliminary detection approach enables proactive prevention rather than reactive response after condensation has already occurred.
2Measurement precision
If a humidity sensor is placed in the high humidity environment near the cooling unit to detect condensation early, then condensation can be predicted earlier, but the humidity sensor cannot operate stably due to condensation liquid attachment
Solution Approach 1:
The patent introduces an air permeable waterproof film as an intermediary between the humidity sensor and the high humidity environment. This film allows water vapor to pass through for accurate humidity detection while blocking liquid condensation, thus maintaining sensor stability and reliability in the high humidity zone near the cooling unit.
3Temperature
If the cooling unit operates continuously to maintain low temperature, then cooling performance is improved, but condensation forms when temperature drops below dew-point temperature
Solution Approach 1:
The humidity sensor provides continuous feedback on humidity levels inside the control unit. When humidity reaches a level indicating imminent condensation, the control portion adjusts the cooling unit's operation to raise the temperature above the dew-point, preventing condensation while maintaining adequate cooling performance.
4Reliability
If the control unit is designed as semi-hermetic with drip-proof and dust-proof structures, then protection against liquid and dust entry is improved, but the internal dew-point temperature equals ambient dew-point, making condensation prevention difficult
Solution Approach 1:
The patent replaces mechanical/structural condensation prevention methods with a sensor-based control system. The humidity sensor and control portion work together to dynamically adjust cooling operation, substituting passive structural protection with active environmental control to prevent condensation while maintaining the semi-hermetic design.
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
This design allows for reliable prevention of condensation formation, maintaining efficient operation and preventing undesired stoppages of the cooling process, thereby enhancing the reliability and performance of the molecular pump.
Implementation Method 1
each of the pump body and the control unit is arranged in contact with or close to the cooling unit, such that the cooling unit and the pump body are brought into thermal contact, and the cooling unit and the control unit are brought into thermal contact
Implementation Method 2
A first temperature detecting portion is provided in a first position, which is a position inside the cover and has a low temperature during operation of the cooling unit. A humidity detecting portion and a second temperature detecting portion are provided in a second position
Implementation Method 3
the dew-point temperature inside the control unit is equal to the dew-point temperature of an ambient environment. Therefore, the portion where the above-described cooling unit is arranged in contact therewith or close thereto has a locally low temperature, and if this temperature decreases below the dew-point temperature, condensation will form on this portion
Implementation Method 4
The control portion controls the operation of the cooling unit in accordance with a relative humidity in the first position, calculated based on temperature information detected by the first temperature detecting portion and the second temperature detecting portion, and based on humidity information detected by the humidity detecting portion
Data Source
AI summary
A molecular pump includes a pump body provided with a turbo molecular pump portion, a control unit provided with a control portion and a power supply portion, and a cooling unit for cooling the pump body and the control unit. A first temperature detecting portion is provided in a first position, which is a position inside the control unit and has a low temperature. A second temperature detecting portion also serving as a humidity detecting portion is provided in a second position, which is a position inside the control unit and has a high temperature. The control portion controls the operation of the cooling unit in accordance with a relative humidity in the first position, calculated based on temperature information detected by the first temperature detecting portion and based on temperature information and humidity information detected by the second temperature detecting portion also serving as a humidity detecting portion.