Concentric Turbine Wheel Layout for Low-Flow Metering
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Solution Overview
Problem
Turbine flowmeters experience reduced accuracy at low flow rates due to rotor/bearing drag, which slows the rotor, and are prone to fouling from particulates.
Innovation Solution
A turbine wheel design with concentric vane sets, magnetic detection, and anti-fouling features, including a magnetically-permeable ferrous part, enhances low flow sensitivity and reduces fouling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional turbine wheel design is used, then manufacturing is simple, but low flow rate measurement accuracy is reduced due to rotor/bearing drag
Solution Approach 1:
The turbine wheel is segmented into multiple functional components: a hub section, multiple blade sets arranged in different planes, and magnetic coupling elements. This segmentation allows each component to be optimized independently - the hub minimizes drag, the blade sets capture flow energy efficiently at different radii, and the magnetic coupling enables non-contact sensing, thereby improving low flow measurement accuracy without excessive complexity
Solution Approach 2:
Multiple blade sets are nested at different radial distances from the hub, with inner blade sets closer to the center and outer blade sets farther out. This nested arrangement allows the turbine to effectively capture kinetic energy across a broader range of flow velocities, improving sensitivity at low flow rates while maintaining a compact overall structure
2Productivity
If turbine wheel rotates at low speed, then low flow rates are detected, but rotor/bearing drag slows the rotor reducing accuracy
Solution Approach 1:
The patent replaces direct mechanical contact between the rotor and bearing/sensing system with magnetic coupling. Magnets embedded in the turbine wheel interact with external sensors without physical contact, eliminating mechanical friction and drag that would otherwise impede rotation at low flow rates. This substitution maintains measurement reliability while enabling detection of very low flow velocities
Solution Approach 2:
The hub design incorporates counterbalancing features and symmetric blade arrangement to minimize rotational inertia and bearing load. By reducing the effective weight and drag on the rotating assembly, the turbine can achieve and maintain rotation at lower speeds corresponding to low flow rates, thereby improving detection capability without sacrificing measurement reliability
3Reliability
If filtering provisions are added to avoid particulate wear, then turbine wheel protection is improved, but device complexity increases
Solution Approach 1:
The patent extracts the sensing function from the flowing stream environment by using external magnetic sensors that detect rotor position without being wetted by the fluid. This extraction eliminates the need for wetted seals and filtering provisions on the rotating components, protecting the turbine wheel from particulate wear while avoiding additional filtering system complexity
Solution Approach 2:
Magnetic field serves as an intermediary between the rotating turbine wheel and the stationary sensing system. The magnetic coupling transmits rotational information across the fluid boundary without requiring physical penetration or contact, thereby protecting the turbine wheel from fouling while maintaining reliable measurement capability
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
The design improves low flow rate measurement accuracy and reduces fouling, achieving sensitivity an order of magnitude lower than industry standards, with improved rotor balance and reduced pressure drop.
Implementation Method 1
Vane movement is often detected magnetically. In certain embodiments, individual vanes are metallic or are embedded with a piece of metal, with each vane or embedded piece of metal generating a pulse detected by electronic sensors. In other embodiments and as applied in current presented art, one or more magnets are positioned diametrically around the turbine wheel.
Data Source
AI summary
A turbine wheel used in a turbine flow meter includes a hub configured to be freely rotatably fixed in position inside a fluid pipe section. A first cylindrical rim is centered about the hub and the longitudinal axis and spaced a distance apart from the hub. A first vane set extends outwardly from the hub to the first cylindrical rim, wherein a root of each vane of the first vane set is attached to the hub and a tip of each vane of the first vane set is attached to the first cylindrical rim. The first vane set may consist of one or two individual vanes. An external vane set may extend outwardly from the first cylindrical rim, wherein a root of each vane is attached to the first cylindrical rim and a tip of each vane is not attached to any cylindrical rim.