Gas Meter Fluid-Dynamic Element for Pressure Drop Reduction
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Solution Overview
Problem
Existing gas meters with thermal-mass sensors face challenges in reducing pressure drop, as solutions like rectifying devices and flow linearizers either fail to comply with regulatory standards or worsen turbulence, leading to inefficient fluid distribution.
Innovation Solution
A fluid-dynamic element with a duct having an inlet port and an outlet port, where the surface area ratio is between 1 and 3.5, and a duct shape that gradually increases in cross-sectional area, reduces fluid flow velocity and turbulence, thereby minimizing pressure drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rectifying device is inserted inside the meter compartment to slow down gas flow, then flow stabilization is improved, but pressure drop increases due to turbulence generation
Solution Approach 1:
The invention extracts the flow linearizing function from the traditional rectifying device located inside the meter compartment and relocates it to a separate element positioned upstream in the inlet duct. This separation removes the harmful turbulence-generating structure from the measurement zone while preserving the beneficial flow stabilization effect, thereby reducing pressure drop without compromising flow linearization.
Solution Approach 2:
The invention introduces an intermediary flow linearizing element positioned between the inlet duct and the meter compartment. This intermediary component prepares the gas flow by reducing turbulence before it enters the measurement zone, acting as a buffer that decouples the flow conditioning function from the measurement function, thus avoiding direct turbulence generation within the meter compartment.
2Measurement precision
If a flow linearizer is added to optimize thermal-mass sensor operation, then measurement accuracy is improved, but fluid-dynamic resistance increases significantly
Solution Approach 1:
The invention segments the meter into distinct functional zones: an inlet duct section containing the flow linearizing element, and a measurement compartment containing the thermal-mass sensor. This segmentation allows the flow linearizer to perform its flow-conditioning function in the inlet section without interfering with the measurement process in the compartment, thereby maintaining measurement accuracy while minimizing energy loss through optimized flow preparation rather than continuous flow restriction.
3Object-generated harmful factors
If the duct cross-sectional area increases gradually from inlet to outlet, then fluid flow velocity is reduced and turbulence is mitigated, but device complexity increases
Solution Approach 1:
The invention employs a duct with gradually varying cross-sectional area, featuring curved transitions instead of abrupt changes. This curved geometry promotes smooth flow acceleration and deceleration, reducing flow separation and turbulence generation. The curved design achieves flow conditioning through geometric optimization rather than complex mechanical components, thereby mitigating turbulence without significantly increasing device 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
The solution effectively limits pressure drop within regulatory limits, ensuring compliance with standards like EN 17526:2018, by mitigating turbulence and reducing fluid-dynamic resistance, as demonstrated by tests showing pressure drops between 180 Pa and 190 Pa at maximum flow rates.
Implementation Method 1
A fluid-dynamic element, which is in fluid communication with the inlet duct, comprises a duct having an inlet port, facing the inlet duct, and an outlet port, facing the measuring compartment
Implementation Method 2
The duct has a shape with a cross-sectional area which gradually increases from the inlet port to the outlet port... reduces fluid flow velocity and turbulence
Data Source
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AI summary
The present invention relates to a fluid measuring device (1), which comprises a box-shaped hollow body (10) delimiting a measuring compartment (11). An inlet duct (12) and an outlet duct (13) allow a flow of fluid to circulate through the measuring compartment (11). In addition, measuring means (2; 20) are arranged inside the measuring compartment (11) and coupled to the outlet duct (13) in order to provide an indication of an amount of fluid flowing through the hollow body (10). In general, the meter has a maximum flow rate between 2.5 m3/h ≤ Qmax ≤ 16.0 m3/h. Advantageously, the fluid measuring device (1) comprises a fluid-dynamic element (5) in fluid communication with the inlet duct (12), so as to be crossed by the flow of fluid before it enters the measuring compartment (11). In particular, the fluid-dynamic element (5) comprises a duct (51) having an inlet port (52) and an outlet port (53), wherein a ratio of the surface area of the outlet port (53) to the surface area of the inlet port (52) is between approximately 1 and approximately 3.5.