Vacuum Pump Rotor Control for Restart After Gas Solidification
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Solution Overview
Problem
Vacuum pumps in semiconductor manufacturing face issues with solidified or liquefied gas constituents accumulating in narrow gaps, hindering rotor rotation and preventing restart, especially when motor torque is limited by frequency converter capacity.
Innovation Solution
An operation control device that rotates pump rotors in forward and/or reverse directions according to a predetermined timing pattern after stopping the vacuum pump, effectively removing accumulated products by applying forces in various directions and optimizing speed settings based on gas type and production state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the vacuum pump is stopped and temperature lowers, then the constituents solidify or liquefy and accumulate in gaps, but this causes the pump rotors to be hindered from rotation and the vacuum pump fails to restart
Solution Approach 1:
The control device performs preliminary action by rotating the pump rotors in reverse direction before normal operation to prevent solidified or liquefied constituents from accumulating in the narrow gaps between pump rotors and casing. This preliminary rotation removes products that would otherwise hinder rotor rotation and prevent restart, ensuring reliable operation resumption after temperature changes.
Solution Approach 2:
The invention applies reverse rotation of the pump rotors contrary to the normal forward rotation direction. This reverse rotation effectively removes solidified or liquefied constituents from the narrow gaps, preventing them from hindering rotor rotation and ensuring the vacuum pump can restart successfully after temperature lowering.
2Productivity
If the vacuum pump operates at high temperature, then favorable evacuation is carried out, but when temperature lowers the products squeeze between gaps and hinder rotor rotation
Solution Approach 1:
The control device implements periodic action by alternately rotating the pump rotors in forward and reverse directions. The reverse rotation occurs periodically to remove solidified or liquefied constituents from narrow gaps, while forward rotation performs normal evacuation. This periodic reverse rotation prevents product accumulation that would hinder rotor rotation, maintaining ease of operation throughout the evacuation process.
3Power
If the electric motor produces limited torque due to frequency converter capacity, then the starting condition becomes severer, but the pump rotors still need to overcome solidified products
Solution Approach 1:
The control device performs preliminary action by rotating the pump rotors in reverse direction before normal operation to prevent solidified or liquefied constituents from accumulating in the narrow gaps between pump rotors and casing. This preliminary rotation removes products that would otherwise hinder rotor rotation and prevent restart, ensuring reliable operation resumption after temperature changes.
Solution Approach 2:
The invention applies reverse rotation of the pump rotors contrary to the normal forward rotation direction. This reverse rotation effectively removes solidified or liquefied constituents from the narrow gaps, preventing them from hindering rotor rotation and ensuring the vacuum pump can restart successfully after temperature lowering.
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
Ensures smooth startup of the vacuum pump by effectively removing solidified or liquefied products from narrow gaps, preventing rotor stalling and motor overheating, even when starting torque is limited.
Implementation Method 1
rotate the pump rotor (1) in forward and/or reverse directions according to a predetermined timing pattern
Implementation Method 2
as the above-mentioned vacuum pump generates compression heat in the process of moving the gas, the vacuum pump in operation is heated up to a certain temperature
Implementation Method 3
When the temperature lowers further, the pump rotors and the pump casing shrink, and gaps between them become narrower
Data Source
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AI summary
To provide an operation control device for a vacuum pump and a method for stopping the operation of the vacuum pump that make it possible to effectively remove products, resulting from solidification and liquefaction of gas in a casing and possibly hindering the rotation of a pump rotor, so that the vacuum pump may be started normally. An operation control device 10 for a vacuum pump having a pump rotor 1 disposed in a casting 2 for free rotation includes a pump rotor control section 15 for controlling the rotation of the pump rotor 1. The pump rotor control section 15 has a function to, after a pump stop action has been taken, rotate the pump rotor 1 in forward and/or reverse directions according to a predetermined timing pattern and then stop the pump rotor 1.