Mass Flow Meter Radial Momentum Device Shear Reduction
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Solution Overview
Problem
Current mass flow meter designs face accuracy issues due to variable shearing forces caused by fluid viscosity changes and temperature fluctuations, which are difficult to account for, leading to measurement errors, especially when maximizing angular momentum and minimizing torque arm length to reduce errors.
Innovation Solution
The design incorporates a housing with a rotatable member and momentum devices connected via biasing elements, featuring a fluid path that changes radial distance within the momentum devices to maintain constant rotational velocity while adding or subtracting angular momentum, thereby reducing shear forces and enhancing measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the torque arm length is maximized to increase angular momentum measurement sensitivity, then measurement precision improves, but shearing forces increase due to viscosity and temperature variations causing measurement errors
Solution Approach 1:
The patent inverts the conventional approach by having the fluid path enter the momentum device at a larger radial distance and exit at a smaller radial distance, opposite to the traditional increasing radius design. This reversal reduces the torque arm length, thereby minimizing shearing forces while still enabling accurate mass flow measurement through the modified geometry
Solution Approach 2:
The patent changes the geometric parameters of the fluid path within the momentum device, specifically the radial distances at entry and exit points. By adjusting these parameters to create a decreasing radius path, the design optimizes the balance between measurement sensitivity and reduction of viscosity/temperature-related errors
2Measurement precision
If the fluid path changes radial distance within the momentum device to reduce shear forces, then measurement accuracy improves, but device complexity increases due to additional design constraints
Solution Approach 1:
The patent combines the flow straightener and momentum device into an integrated structure where the flow straightener is positioned within the momentum device. This merging reduces the number of separate components while achieving both flow conditioning and angular momentum measurement functions, thereby managing complexity
Solution Approach 2:
The momentum device serves multiple functions: it acts as both the measurement element for angular momentum and houses the flow straightener for flow conditioning. This multi-functionality reduces the need for separate dedicated components, simplifying the overall device structure despite the complex fluid path geometry
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 minimizes shear forces at the momentum device interfaces, reducing errors related to viscosity and temperature variations, allowing for more accurate mass flow calculations and improved measurement precision.
Implementation Method 1
The rotatable member is biased in a first position by a spring arranged between the rotatable member and the housing
Implementation Method 2
the fluid path enters the momentum device at a radial distance r1 from the axis and exits the momentum device at a radial distance r2 from the axis, and wherein r1 and r2 are different distances
Data Source
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AI summary
A mass flow meter (10, 50, 130, 200, 300) comprising a housing (11) including a fluid inlet (4) and a fluid outlet (6, 36). The housing (11) defines a chamber (13) and a rotatable member (12A, 12B, 60A, 60B, 210A, 210B) is arranged in the chamber (13) so as to be rotatable about an axis (24). A momentum device (14, 15) is also arranged in the chamber (13) and connected to the rotatable member (12A, 12B, 60A, 60B, 210A, 210B) via a connection comprising a biasing element (9, 52) so as to be rotatable about the axis (24) and rotatable relative to the rotatable member (12A, 12B, 60A, 60B, 210A, 210B). A fluid path (34) in fluid communication with the fluid inlet (4) and the fluid outlet (6, 36) is provided. The fluid path (34) passes through both the rotatable member (12A, 12B, 60A, 60B, 210A, 210B) and the momentum device (14, 15). The fluid path (34) enters the momentum device (14, 15) at a radial distance r1 from the axis (24) and exits the momentum device (14, 15) at a different radial distance r2 from the axis (24). A torque provider (21, 56) may be coupled to the rotatable member (12A, 12B, 60A, 60B, 210A, 210B) via a shaft (8, 62) or gear member (58).