Vacuum Pump Flooding Valve Segmentation for Rotor Protection
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Solution Overview
Problem
Vacuum chambers connected to turbomolecular pumps take a long time to flood due to small venting valve cross-sections, leading to excessive gas loads on the rotor, which can cause damage, especially in larger chambers.
Innovation Solution
The method involves increasing the flooding rate once a predeterminable pressure limit is reached in the vacuum pump, using a larger fluid cross-section and controlling the flood valve to switch from a smaller to a larger flow after the rotor has been switched off, ensuring minimal forces act on the rotor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a small cross-section flooding valve is used, then the rotor is protected from excessive gas loads, but the flooding time becomes excessively long
Solution Approach 1:
The flooding process is divided into two distinct phases: an initial phase with a first flooding valve (small cross-section) to protect the rotor, and a subsequent phase with a second flooding valve (large cross-section) to rapidly fill the chamber. This segmentation allows each valve to be optimized for its specific function, resolving the contradiction between rotor protection and flooding speed.
Solution Approach 2:
The first flooding valve performs the preliminary action of safely initial flooding and pressure equalization before the second flooding valve is activated. This preliminary action prepares the system by reducing the pressure differential to a safe level, enabling the subsequent rapid flooding without endangering the rotor.
2Loss of time
If a large cross-section flooding valve is used, then the flooding time is reduced, but excessive gas loads act on the rotor causing damage
Solution Approach 1:
The flooding function is segmented between two valves with different cross-sections. The first valve handles the critical initial phase with limited flow capacity to protect the rotor, while the second valve handles the subsequent phase with high flow capacity for rapid flooding, eliminating the need to choose between safety and speed.
Solution Approach 2:
The system dynamically transitions from using the first flooding valve to using the second flooding valve based on the pressure differential conditions. This dynamic adaptation allows the system to optimize the flooding rate at different stages, preventing rotor damage during initial flooding while achieving rapid overall flooding.
3Productivity
If the flooding rate is increased from the beginning, then the flooding process is accelerated, but excessive forces act on the still-rotating rotor
Solution Approach 1:
The first flooding valve performs the preliminary action of controlled initial flooding at a restricted rate, preventing excessive forces on the rotor. Once this preliminary phase is complete and the pressure differential is reduced, the second flooding valve takes over to achieve high-speed flooding, thus achieving both rotor protection and high productivity.
Solution Approach 2:
The flooding process employs periodic action by switching between two distinct flooding modes: an initial restricted mode through the first valve, and a subsequent accelerated mode through the second valve. This periodic transition optimizes both rotor protection and flooding efficiency at different time intervals.
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 allows for rapid and safe flooding of larger vacuum chambers without impairing the rotor, significantly reducing the flooding time and minimizing the risk of damage.
Implementation Method 1
the flooding rate, i.e., the flow rate at which the gas used for ventilation can be supplied
Data Source
Figure 1~2
Figure 3
AI summary
A method for flooding a vacuum chamber connected to a vacuum pump, in particular a turbomolecular pump, in which the vacuum pump, comprising a rotor and a stator, is simultaneously flooded along with the vacuum chamber, is characterized in that the flooding occurs immediately after the pump rotor is switched off and the flooding rate is increased during each flooding process as soon as the pressure in the vacuum pump reaches a predefinable limit. A suitable apparatus for carrying out the method is also described.