Grinding Container Particle Size Measurement
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Solution Overview
Problem
Ball mills face inefficiencies in achieving desired particle sizes due to the inability to monitor particle size during grinding in closed gas atmospheres, leading to uneconomical operations and potential material waste, especially when grinding metal hydrides which can be damaged by oxygen exposure.
Innovation Solution
A device with a measuring system that allows continuous or discontinuous particle size measurement using laser diffractometry, connected to the grinding container via a gas supply line to prevent clogging and maintain a representative sample, enabling real-time adjustment of grinding parameters and maintaining a consistent gas atmosphere through overpressure and a return line for recirculating particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the grinding chamber is kept closed to maintain gas atmosphere integrity, then material protection from oxygen exposure is improved, but the ability to monitor and adjust particle size during grinding deteriorates
Solution Approach 1:
The grinding system is segmented into a closed grinding chamber and a separate measurement chamber connected by a sampling line. This allows particle sampling for size measurement while maintaining the integrity of the closed gas atmosphere in the grinding chamber, resolving the contradiction between atmosphere protection and measurement capability.
Solution Approach 2:
An inert gas stream acts as an intermediary to transport particles from the grinding chamber through the sampling line to the measurement chamber. This mediator enables particle size measurement without direct opening of the grinding chamber, thus maintaining gas atmosphere integrity while providing measurement capability.
2Ease of operation
If grinding parameters are adjusted without real-time particle size feedback, then operational simplicity is maintained, but grinding efficiency and material economy deteriorate
Solution Approach 1:
A feedback loop is established where particle size is continuously measured in real-time during grinding, and this measurement information is used to automatically adjust grinding parameters. This feedback mechanism improves grinding efficiency and material economy while maintaining ease of operation through automated control.
3Manufacturing precision
If multiple grinding attempts are made to achieve desired particle size, then particle size target is eventually achieved, but material waste and operational cost increase
Solution Approach 1:
Particle size measurement is performed preliminarily during the grinding process rather than only after completion. This preliminary measurement allows real-time assessment of grinding progress and adjustment of parameters, ensuring the desired particle size is achieved with minimal grinding time and material waste.
4Measurement precision
If the sampling connection is opened frequently for particle removal, then particle size measurement capability is improved, but gas atmosphere integrity and connection clogging worsen
Solution Approach 1:
The gas stream flowing through the sampling line operates continuously to prevent particle accumulation and clogging at the connection point. This continuous action maintains measurement capability while minimizing the need to open the grinding chamber, thus preserving gas atmosphere integrity.
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 precise control of grinding parameters, reducing the number of grinding attempts needed to achieve the desired particle size, ensuring economical operation and maintaining the integrity of the gas atmosphere, thus preventing material waste and ensuring consistent product quality.
Implementation Method 1
The particle size is preferably determined by means of laser diffractometry. Particles are removed from the grinding container in a gas extraction flow and guided past a laser beam at a measuring point of the measuring device for laser diffractometry.
Implementation Method 2
The measuring device is connected to a gas supply line and designed to direct a gas supply flow from the gas supply line through the connection port into the grinding chamber in a first switching state during the grinding process.
Implementation Method 3
The measuring device is further designed to generate a negative pressure in a second switching state using the gas supply stream flowing out of the gas supply line in order to suck in a gas withdrawal stream with the particles contained therein from the grinding chamber
Data Source
Figure 1
AI summary
The invention relates to a device (1) for high-energy and/or fine grinding of particles using free-flowing grinding media in a closed gas atmosphere and to a method for high-energy and/or fine grinding of particles. The device (1) comprises a grinding container (2) for receiving the particles and the grinding media, with a closed housing (3) and a grinding chamber (4) located therein. A rotor (6) for accelerating the grinding media during a grinding process is rotatably mounted in the grinding container (2). The grinding container (2) is cylindrical and extends along a horizontal longitudinal axis (5). The device (1) includes a measuring device (12) for measuring the particle size. The grinding container (2) has at least one connection port (10, 17, 20) for connecting to the measuring device (12).The measuring device (12) is connected to the grinding container (2) in such a way that particles can be taken from the grinding chamber (4) and measured during a grinding process.