Turbo-Molecular Pump Startup Timing via Backing Pump Pressure Measurement
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Solution Overview
Problem
The existing method for starting a vacuum pumping device requires pre-storing chamber volume data, which is cumbersome and can result in improper timing of the turbo-molecular pump start if not accurately prepared.
Innovation Solution
A vacuum pumping device with a measurement section to determine the first elapsed time until the backing pump reaches a predetermined pressure, and an arithmetic section to calculate the second elapsed time for the turbo-molecular pump start, eliminating the need for pre-stored chamber volume data by using a pressure switch and time measurement to ensure proper timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chamber volume data is pre-stored and used for calculation, then the turbo-molecular pump can be started at proper timing, but the preparation process becomes cumbersome and complex
Solution Approach 1:
The system automatically measures the chamber volume by timing how long it takes for the backing pump to reach a predetermined pressure, eliminating the need for manual input or pre-storation of chamber volume data. The arithmetic section then uses this automatically obtained measurement to calculate the optimal start timing for the turbo-molecular pump.
Solution Approach 2:
The chamber volume is measured in advance during the backing pump operation phase, before the turbo-molecular pump needs to be started. This preliminary measurement and calculation ensures that when the turbo-molecular pump is started, the timing is already optimized based on the actual chamber characteristics.
2Ease of operation
If chamber volume is not accurately stored, then the preparation process is simplified, but the turbo-molecular pump is not started at proper timing
Solution Approach 1:
The manual process of checking and storing chamber volume data is replaced with an automated measurement system using a pressure gauge and timer. The system electronically measures the time for the backing pump to reach a predetermined pressure and automatically calculates the optimal turbo-molecular pump start timing, replacing manual data entry with automated sensing and computation.
Solution Approach 2:
The system uses real-time pressure monitoring during backing pump operation to determine chamber volume characteristics. The measured time to reach predetermined pressure provides feedback about the chamber's evacuation characteristics, which is then used by the arithmetic section to calculate the precise timing for turbo-molecular pump startup.
3Measurement precision
If manual checking and storing of chamber volume is required, then data accuracy can be ensured, but the preparation process takes a lot of trouble and time
Solution Approach 1:
The chamber volume measurement is performed continuously during the normal backing pump operation rather than as a separate preparatory step. The system measures the time for the backing pump to reach a predetermined pressure, and this measurement is seamlessly integrated into the pump startup sequence, eliminating idle preparation time while maintaining measurement accuracy.
Solution Approach 2:
The backing pump serves as an intermediary tool for measuring chamber volume characteristics. Instead of requiring a separate measurement procedure, the system uses the backing pump's normal operation and pressure progression as the measurement mechanism, thereby obtaining chamber volume data without adding extra preparation steps.
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 solution allows for the proper and timely start of the turbo-molecular pump without requiring pre-stored chamber volume data, enhancing operability and simplifying the preparation process.
Implementation Method 1
The measurement section includes a pressure gauge configured to measure the suction-port-side pressure of the backing pump
Implementation Method 2
a pressure difference gauge configured to measure a pressure difference between the suction-port-side pressure and the atmospheric pressure
Implementation Method 3
a time measurement section configured to measure, as the first elapsed time, time until the measurement pressure of the pressure gauge reaches a predetermined pressure
Implementation Method 4
t2={loge(P0/P2)/loge(P0/P1)}×t1
Implementation Method 5
an backing pump connected to an outlet side of the turbo-molecular pump
Data Source
AI summary
A vacuum pumping device comprises: a turbo-molecular pump; an backing pump connected to an outlet side of the turbo-molecular pump; a measurement section configured to measure first elapsed time until a suction-port-side pressure of the backing pump reaches a predetermined pressure higher than a turbo-molecular pump startable pressure and lower than an atmospheric pressure after start of the backing pump; an arithmetic section configured to calculate, based on the first elapsed time measured by the measurement section, the atmospheric pressure, and the predetermined pressure, second elapsed time until the suction-port-side pressure reaches the turbo-molecular pump startable pressure after the start of the backing pump; and a start control section configured to start the turbo-molecular pump when the second elapsed time has elapsed after the start of the backing pump.