Vacuum System Bypass Line for Steel Degassing Pump-Down
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Solution Overview
Problem
Existing vacuum systems for steel degassing are inefficient due to the slow evacuation rate caused by equalizing pressure between the degassing chamber and the filter volume at lower pressures, which reduces the pumping capacity and prolongs the time to reach the target pressure.
Innovation Solution
A vacuum system with a by-pass line that initially evacuates the chamber at a higher pressure without the filter volume, then connects the filter volume to achieve faster gas removal by equalizing pressure, allowing the vacuum pumping arrangement to operate more efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the filter volume is connected to the chamber at the beginning of evacuation to equalize pressure, then the chamber pressure is immediately reduced, but the pumping capacity decreases and the time to reach target pressure increases
Solution Approach 1:
The filter volume is pre-evacuated to a low pressure (e.g., 10 mbar) before the chamber evacuation process begins. This preliminary action ensures that when the filter connects to the chamber, the pressure equalization immediately reduces chamber pressure without requiring the pump to work against a large pressure differential, thereby maintaining high pumping capacity and achieving faster pump-down speeds.
Solution Approach 2:
The evacuation process is segmented into distinct phases: initial chamber evacuation through the bypass line, filter volume pre-evacuation, and then filter connection for final polishing. This segmentation allows each component to operate optimally at different stages, with the pump operating at high capacity during initial evacuation and the filter providing fine filtration during the final approach to target pressure.
2Quantity of substance
If the filter volume is large to handle the volumetric flow, then the filtering capacity is sufficient, but the volume to be evacuated increases and the evacuation time prolongs
Solution Approach 1:
The filter volume is pre-evacuated before connecting to the chamber, removing the majority of the gas load in advance. This preliminary action reduces the amount of gas that needs to be evacuated from the combined chamber-filter system, thereby reducing the evacuation time despite the large filter volume required for adequate filtering capacity.
3Power
If the bypass line is used for initial evacuation, then the pumping capacity is maintained at high level, but the filter volume is not utilized for pressure equalization
Solution Approach 1:
The filter volume is pre-evacuated through the bypass line before chamber connection, utilizing the high pumping capacity during this preliminary phase. This ensures the filter is ready to immediately assist in pressure reduction when connected to the chamber, maximizing overall evacuation efficiency by combining high-power initial evacuation with efficient final polishing.
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 approach reduces the time to reach the target pressure in the chamber by leveraging higher pressure efficiency during initial evacuation and subsequent equalization, resulting in faster pump-down speeds compared to traditional methods.
Implementation Method 1
A filter volume 18 is located in the foreline for filtering gas evacuated from the chamber along the foreline
Implementation Method 2
the pressure differential causes gas to flow from the chamber into the filter volume
Data Source
AI summary
The present invention relates to a vacuum system for evacuating a chamber of a metallurgical processing system. The system comprises a vacuum pumping arrangement for evacuating gas from the chamber, a foreline connecting the vacuum pumping arrangement to the chamber, a filter volume located in the foreline for filtering gas evacuated from the chamber along the foreline, and a by-pass line connecting the vacuum pumping arrangement to the chamber and arranged to by-pass the filter volume selectively dependent on monitored characteristics of the degassing chamber or the vacuum system.