Dam-Shaped Throttling Block for Abrasive Flow Measurement
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Solution Overview
Problem
Wedge-type throttling elements in flow meters suffer from rapid wear and reduced accuracy when measuring abrasive fluids, leading to frequent replacements and high head loss, limiting their application to high Reynolds number fluids with low viscosity and no solids.
Innovation Solution
A dam-shaped throttling block with inclined flat surfaces and an elliptical aperture is used, reducing cross-sectional area gradually to minimize turbulence and abrasion, maintaining measurement accuracy and extending service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a wedge-shaped throttling element is used to measure flow rates of abrasive fluids, then measurement capability is provided, but the edge deteriorates rapidly causing loss of measurement accuracy
Solution Approach 1:
The patent replaces the sharp wedge edge with a curved profile. The throttling element features a rounded leading edge that gradually transitions into the throttling section, eliminating the sharp edge that is susceptible to wear. This curvature allows the element to maintain its throttling function while resisting deterioration from abrasive fluids, thereby preserving measurement accuracy over extended periods.
Solution Approach 2:
The patent modifies the geometric parameters of the throttling element by transitioning from a fixed wedge angle to a variable curvature profile. The rounded edge introduces a continuous change in the flow angle, replacing the abrupt angular transition. This parameter change reduces stress concentration and wear at the leading edge while maintaining effective flow throttling.
2Adaptability or versatility
If a wedge-shaped throttling element is used, then flow measurement is enabled, but head loss is relatively high
Solution Approach 1:
The curved profile of the throttling element creates a more gradual flow transition compared to the sharp wedge. The rounded leading edge and curved throttling section reduce flow separation and turbulence, allowing for smoother fluid passage. This reduces energy dissipation and minimizes head loss while maintaining the necessary flow throttling for measurement.
Solution Approach 2:
By changing the geometric parameters from fixed angular wedges to variable curvature profiles, the patent optimizes the flow path. The continuous curvature variation allows for better flow attachment and reduced turbulence, thereby decreasing energy loss and head pressure drop across the throttling element.
3Strength
If the edge of the wedge is hardened with stellite or tungsten carbide cladding to resist wear, then abrasion resistance is improved, but the edge still wears eventually and replacement is needed
Solution Approach 1:
The rounded edge design eliminates the stress concentration points inherent in sharp edges, distributing wear more uniformly across the curved surface. This geometric modification reduces the rate of material degradation and minimizes the effectiveness of abrasive wear mechanisms, extending the service life of the throttling element even without heavy cladding.
Solution Approach 2:
By fundamentally changing the edge geometry from sharp to rounded, the patent alters the wear characteristics. The curved profile reduces contact stress and improves fluid flow patterns, decreasing the mechanical and erosive forces that cause wear. This parameter change extends operational duration beyond what is achievable with hardened materials alone.
4Loss of energy
If a Venturi tube is used for flow measurement, then head loss is reduced, but it is only useful for very high Reynolds numbers with low viscosity and clean fluids
Solution Approach 1:
The curved throttling profile creates a more gradual flow transition similar to Venturi tubes, reducing turbulence and head loss. However, unlike traditional Venturi tubes, this design maintains effectiveness across a broader Reynolds number range and with abrasive or viscous fluids, combining the energy efficiency of Venturi-style flow paths with enhanced versatility.
Solution Approach 2:
The patent creates a throttling element that combines the low head loss characteristics of Venturi tubes with the ability to handle diverse fluid types including abrasive, viscous, and dirty fluids. The curved profile achieves smooth flow transitions for energy efficiency while being less susceptible to fouling and wear, providing universal applicability across multiple fluid conditions.
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 dam-shaped throttling block provides improved measurement accuracy, reduced head loss, and prolonged service life, allowing for the measurement of viscous and abrasive fluids with minimal installation space requirements.
Implementation Method 1
The wedge 14 creates a pressure drop in the fluid within the pipe 12, which can be measured by calculating the difference between the upstream pressure measured at upstream port or pressure tap 34 and the downstream pressure measured at downstream port or pressure tap 36.
Data Source
AI summary
A dam-shaped throttling block for use in a pipe, for the measurement of the flow rates of fluids. The shapes of four successive flat surfaces on the throttling block angularly-displaced relative one another in the flow direction, together with an aperture in the one of the flat surfaces extending parallel to the pipe longitudinal axis, create reduction of a cross-sectional area in one step from one that is unthrottled to one that is throttled, extending for a limited distance in the pipe, and then expansion of the cross-sectional area in two steps from the throttled one back to the unthrottled one so to provide for accurate measurements and an improved lifetime. Flow rates of highly viscous fluids and fluids that contain solid particles can be measured. Other benefits include reduced head loss, wide measurement range and reduced installation space.