Spatially Resolved Charge Distribution Measurement in Pneumatic Conveying
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Solution Overview
Problem
Existing methods for determining the charge distribution of particles in a gas stream are limited, as they only measure the total electrical charge and lack spatial resolution, which can lead to undetected excessive electrostatic charges and increased risk of explosions.
Innovation Solution
A method for determining the spatially resolved charge distribution using a pneumatic conveying device that applies a transverse electric measuring field, allowing for the detection of both positive and negative charges and providing detailed spatial information on charge distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Faraday cups are used to measure total electrical charge, then the sum of charges can be recorded, but spatial resolution is lost and positive/negative charges cannot be distinguished
Solution Approach 1:
The patent divides the measurement task into multiple spatial segments by using several measurement planes positioned at different locations along the gas stream. Each plane independently measures charge characteristics at its specific location, enabling spatially resolved charge distribution measurement while maintaining the ability to distinguish positive and negative charges through the use of multiple electrodes in each plane
Solution Approach 2:
The patent transitions from one-dimensional total charge measurement (Faraday cup) to three-dimensional spatial charge distribution measurement by introducing multiple measurement planes along the flow direction and multiple electrodes in each plane. This dimensional expansion allows simultaneous measurement of charge magnitude, polarity, and spatial location
2Device complexity
If traditional charge measurement methods are used, then the measurement setup is simple, but spatially resolved charge distribution cannot be detected
Solution Approach 1:
The measurement system is segmented into multiple independent measurement planes, each with its own electrode arrangement. This segmentation allows the complex task of 3D charge distribution measurement to be broken down into multiple 2D plane measurements, making the overall system manageable while achieving high spatial resolution
Solution Approach 2:
Each measurement plane serves multiple functions: it measures both positive and negative charges, provides spatial localization, and can operate independently or in combination with other planes. This multi-functionality reduces the need for separate measurement systems for different charge characteristics
3Reliability
If no electric field is applied during measurement, then particles are not disturbed, but charge distribution cannot be characterized
Solution Approach 1:
The patent uses tracer particles as intermediaries to indirectly measure the gas flow velocity. These tracer particles follow the gas flow without significantly disturbing it, allowing velocity field measurement while maintaining measurement non-intrusiveness. The charge measurement electrodes similarly act as intermediaries that detect charge without substantial particle interaction
4Measurement precision
If measurement time is extended to capture sufficient particles, then statistical accuracy improves, but measurement efficiency decreases
Solution Approach 1:
By dividing the measurement domain into multiple parallel measurement planes, the system captures charge information from different spatial locations simultaneously. This parallel measurement approach increases the total number of particles measured per unit time, improving both statistical accuracy and measurement efficiency
Solution Approach 2:
The measurement system operates continuously with multiple planes collecting charge data simultaneously as particles flow through. This continuous parallel measurement eliminates idle time between measurements and maximizes particle utilization, achieving both high accuracy and fast measurement
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 method enables the detection of excessive electrostatic charges with greater certainty, reducing the risk of explosions by providing spatially resolved information on charge distribution, which is not possible with existing technologies.
Implementation Method 1
When particles are transported in a gas stream, especially an air stream, they often become electrostatically charged
Implementation Method 2
a measuring field generator (28) for applying an electric field to the particle-containing gas stream
Implementation Method 3
a particle velocity meter (34) for measuring a velocity of the particles in the gas stream
Data Source
Figure 1~1b
AI summary
The invention relates to a method for determining at least one charge characteristic value (K) of electrical charges of particles (16) in a fluid stream, having the steps of: (a) conducting the fluid stream containing particles (16) through a fluid line (20), (b) determining a measuring-fieldless particle speed (v) in a spatially resolved manner in a measuring region without an electric measuring field, (c) applying an electric measuring field transversely to the flow direction (S) in the measuring region, (d) determining a with-field particle speed (vE) in a spatially resolved manner in the measuring region, and (e) determining the at least one charge characteristic value (K), which describes an electrostatic charge of the particles (16), from the spatially resolved particle speeds.