Absolute Mass Balance Using Electromagnetic Force Comparison
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Solution Overview
Problem
Conventional mass measurement techniques rely on traceability to reference mass standards, which is tedious and limited in precision for small masses, and require vacuum environments and quantum electrical standards, making them inefficient for direct realization of small masses.
Innovation Solution
An absolute mass balance system using a dual diameter wheel with a main mass arm, counter mass arm, and a magnet system to compare the weight of an object to a calibrated electromagnetic force, operating in velocity and force modes to determine mass independently of reference standards, allowing operation in air without vacuum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional mass measurement techniques are used, then traceability to reference mass standards is achieved, but the process becomes tedious and precision is limited for small masses
Solution Approach 1:
The patent replaces conventional mechanical reference standard comparison with an electromagnetic force measurement system. A coil in a magnetic field generates a calibrated electromagnetic force that directly balances the gravitational force on the mass, eliminating the need for mechanical reference standards and traceability chains. This substitution of mechanical comparison with electromagnetic measurement achieves higher precision for small masses while reducing system complexity.
Solution Approach 2:
The patent changes the measurement parameter from mechanical force comparison to electromagnetic force generation. By controlling electrical current through a coil in a known magnetic field, the system generates a precisely known electromagnetic force (F=BIL) that directly counterbalances the object's weight. This parameter change from mechanical to electromagnetic domain enables direct mass determination without reference standards.
2Measurement precision
If vacuum environments and quantum electrical standards are required, then accurate mass determination is possible, but the system becomes inefficient for direct realization of small masses
Solution Approach 1:
The patent extracts and eliminates the requirement for vacuum environments from the measurement system. By using an electromagnetic force balance method, the system can operate directly in air, removing the complex vacuum chamber infrastructure while maintaining measurement accuracy. This extraction of the vacuum requirement significantly simplifies operation and improves efficiency for routine small mass measurements.
3Productivity
If reference mass standards are used for calibration, then mass measurement is possible, but the process is tedious and time-consuming
Solution Approach 1:
The patent implements a self-calibrating system where the electromagnetic force generation provides an absolute reference based on fundamental electrical units (ampere, meter, second) rather than requiring external mass standards. The system determines mass directly through the relationship F=mg=BIL, where B, I, and L are precisely known electrical and geometric parameters. This self-service capability eliminates tedious calibration procedures and enables rapid mass determination.
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
Enables precise determination of small masses with relative uncertainties on the order of parts per million, eliminating the need for complex traceability chains and vacuum environments, and providing a direct realization of mass units at the gram level.
Implementation Method 1
a permanent magnet disposed between the first main coil and the second main coil and that produces a third magnetic field that interacts with the first magnetic field and the second magnetic field
Implementation Method 2
an eddy current damper in mechanical communication with the counter mass arm that moves with the counter mass arm, that provides a constant velocity of the main mass receiver, and that suppresses a pendulum mode of the driving motor
Implementation Method 3
a displacement measuring system in mechanical communication with the permanent magnet such that displacement measuring system provides a null position of the dual diameter wheel and measures a velocity of the main magnet system
Data Source
AI summary
An absolute mass balance determines an absolute mass of an object and includes: a dual diameter wheel including: a balance fulcrum; and a balance beam disposed on the balance fulcrum and including: a main mass arm and a counter mass arm; a main mass receiver that receives the object; a main magnet system including: a first main coil that produces a first magnetic field; a second main coil that produces a second magnetic field; and a permanent magnet that produces a third magnetic field that interacts with the first magnetic field and the second magnetic field; a displacement measuring system that provides a null position of the dual diameter wheel and measures a velocity of the main magnet system; and a driving motor including: an eddy current damper that provides a constant velocity of the main mass receiver; and a counter mass magnet system.