Turbomolecular Vacuum Pump Vibration Control With Motion Feedback
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Solution Overview
Problem
Vacuum pumps, particularly turbomolecular vacuum pumps, experience vibrations and movements that disrupt smooth operation and can be transmitted to connected devices, causing issues like image distortion in electron microscopes.
Innovation Solution
Incorporating a motion sensor to detect the vacuum pump's movement and adjust the rotor's position or rotational speed to minimize vibrations, using electromagnetic bearings and a control unit to maintain the rotor within a tolerance range, thereby reducing overall pump movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic bearings are used to keep the rotor at a distance from the stator, then contact-free rotational mounting is achieved, but the vacuum pump experiences movements and vibrations that disrupt smooth operation
Solution Approach 1:
The patent implements a feedback control system where motion sensors detect the position and movement of the vacuum pump body, and this information is fed back to the control unit. The control unit adjusts the electromagnetic bearing currents in real-time to compensate for movements and minimize vibrations, thereby maintaining smooth operation while preserving contact-free rotational mounting.
Solution Approach 2:
The patent dynamically changes the electrical parameters (current magnitude and distribution) of the electromagnetic bearing coils based on detected motion. By adjusting these parameters in response to real-time motion feedback, the system optimizes the electromagnetic forces to counteract vibrations and minimize pump body movement, resolving the contradiction between contact-free mounting and vibration reduction.
2Productivity
If the rotor is rotated at high speed to evacuate the recipient, then pumping efficiency is improved, but vibrations and movements increase
Solution Approach 1:
The motion sensors continuously monitor the vacuum pump's movements during rotor rotation, and the control unit uses this feedback to dynamically adjust electromagnetic bearing currents. This real-time compensation reduces vibrations caused by high-speed rotation while maintaining the pumping efficiency achieved through high rotor speeds.
Solution Approach 2:
The patent employs dynamic control of the electromagnetic bearing system, where the bearing currents are continuously adjusted during rotor operation. This dynamic adjustment allows the system to maintain high rotation speeds for efficient pumping while actively compensating for the resulting vibrations and movements, thus resolving the contradiction between productivity and harmful vibrations.
3Object-affected harmful factors
If motion sensors and control systems are added to reduce vibrations, then smooth running is improved, but device complexity increases
Solution Approach 1:
The control unit utilizes existing sensors and processing capabilities within the vacuum pump system, allowing it to self-regulate the electromagnetic bearing currents based on detected motion. This self-service approach minimizes the need for additional external control systems while achieving vibration reduction, thus limiting the increase in device complexity.
Solution Approach 2:
The patent integrates the vibration control functionality into the existing control unit of the vacuum pump, which already manages the electromagnetic bearings for contact-free rotation. By making the control unit multi-functional (handling both bearing control and vibration compensation), the system achieves smooth running without requiring separate dedicated control systems, thereby limiting complexity increase.
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
The solution significantly reduces the vacuum pump's movement, leading to smoother operation and minimizing vibrations transmitted to connected devices, enhancing the stability of applications like electron microscopy.
Implementation Method 1
The electromagnetic attractive forces generated here keep the rotor at a distance from the stator. In principle, it is also conceivable to keep the rotor at a distance from the stator using electromagnetic repulsion forces.
Implementation Method 2
A measure taken by the control unit may be to change a rotational speed of the rotor. By changing the rotor rotational speed, vibration-inducing resonance frequencies can be avoided.
Data Source
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AI summary
The invention relates to a vacuum pump, in particular a turbomolecular vacuum pump, comprising a stator, a rotor rotatable about an axis of rotation with respect to the stator, a bearing unit with at least one electromagnetic bearing for contactless rotational support of the rotor with respect to the stator, at least one distance sensor configured to measure a distance between the rotor and the stator during operation, and a control unit configured to take action based on a distance measurement provided by the distance sensor, wherein the vacuum pump comprises at least one motion sensor, in particular an accelerometer or angular rate sensor, configured to detect movement of the vacuum pump, in particular vibrations, and to provide at least one motion measurement based on the detected movement, and wherein the control unit is further configured toThe invention relates to the motion measurement value provided by the motion sensor when taking action. Furthermore, the invention relates to a vacuum system comprising such a vacuum pump and a vacuum device. The invention also relates to a method for operating a vacuum pump and a method for operating a vacuum system.