Magnetic Inductive Flow Meter Field Settling
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Solution Overview
Problem
Existing magneto-inductive flowmeters face challenges in maintaining a constant magnetic field strength during measurements, leading to errors in flow rate determination due to fluctuations, and current methods require a commutation interval that is too long to accurately measure short-term flow fluctuations.
Innovation Solution
The method involves dividing the commutation interval into two sub-intervals with distinct current profiles, where the first interval has a differential current profile to rapidly increase the magnetic field strength, and the second interval maintains a constant current to achieve a stable magnetic field, allowing for shorter settling times and improved measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a constant target current is specified for the current controller to generate a constant magnetic field strength, then the magnetic field stability is improved, but the settling time increases and the commutation interval becomes too long to measure short-term flow fluctuations
Solution Approach 1:
The commutation interval is divided into two distinct sub-intervals: a first sub-interval for rapidly changing the magnetic field strength to a target value, and a second sub-interval for maintaining constant magnetic field strength during measurement. This segmentation allows the system to achieve both fast settling and stable measurement conditions.
Solution Approach 2:
The patent applies dynamic control by using different current controller settings for different phases of the commutation interval. During the first sub-interval, the current controller is configured for rapid response to change magnetic field strength quickly. During the second sub-interval, the controller maintains constant current for stable field strength. This dynamic adaptation resolves the contradiction between fast settling and stability.
2Measurement precision
If the commutation interval is shortened to measure short-term flow fluctuations, then the measurement precision for fluctuating flows is improved, but the magnetic field strength cannot stabilize leading to measurement errors
Solution Approach 1:
By segmenting the commutation interval into two functional sub-intervals, the patent enables the total interval to be shortened while ensuring adequate time for both field establishment and stable measurement. The first sub-interval handles rapid field changes, and the second sub-interval ensures stable measurement conditions, together achieving both speed and precision.
Solution Approach 2:
The first sub-interval performs preliminary action by rapidly establishing the magnetic field strength to its target value before the measurement phase begins. This preliminary field establishment ensures that when the second sub-interval starts, the magnetic field is already stable and ready for accurate flow measurement.
3Device complexity
If a single constant target current is used throughout the commutation interval, then the control simplicity is maintained, but the ability to achieve both fast settling and stable measurement is compromised
Solution Approach 1:
The control system dynamically adjusts the target current profile based on the phase of the commutation interval. During the first sub-interval, the target current is set to enable rapid field establishment. During the second sub-interval, the target current is set to maintain constant field strength. This dynamic control strategy improves productivity while maintaining reasonable system complexity.
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 significantly shortens the settling time, enabling more precise flow rate measurements, especially for media with short-term fluctuations, by ensuring a constant magnetic field strength is established quickly.
Implementation Method 1
the electromagnet has a current regulator and a coil arrangement, the current regulator generates a coil current and the coil current generated brings about the magnetic field in the coil arrangement
Implementation Method 2
a magnetic field it generates at least partially penetrates the medium located in the measuring tube and a flow of the medium in the measuring tube induces an induction voltage in the medium
Data Source
Figure 1
Figure 2a~2d
AI summary
Described and illustrated is a method for setting a constant magnetic field strength of a magnetic field (4) within a commutative interval in a magnetic-inductive flowmeter (1) with a current controller (6). The invention is based on the objective of providing a method for setting the constant magnetic field strength in which the settling time is shortened compared to the prior art.The problem is solved by arranging a first interval with a start time and an end time and a second interval with a start time and an end time within the commutation interval, by determining a first target current profile for the first interval, wherein the first target current profile deviates from the constant target current by a differential current profile such that the differential current profile causes a higher rate of change of the magnetic field strength towards the constant magnetic field strength compared to the constant target current, by determining a second target current profile for the second interval by assigning the constant target current to the second target current profile, and by specifying the first target current profile to the current controller (6) in the first interval and the second target current profile in the second interval.