In-Line Flowmeter for Large Diameter Pipes
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Solution Overview
Problem
Existing flowmeters face challenges in accurately measuring mass or volumetric flow in large diameter pipes without causing significant downstream pressure drops, especially for pipes exceeding 14 inches in diameter, due to size and weight limitations of conventional flowmeters like Coriolis meters, and the need for necking down pipes leads to additional pressure losses.
Innovation Solution
An in-line flowmeter design featuring an interior measuring tube within a larger pipe, allowing conventional flowmeters to operate within the inner tube, with flow measurements from the inner tube scaled to represent the total flow through both the inner and outer pipes, minimizing pressure drops and maintaining accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional flowmeters (Coriolis, magnetic, ultrasonic) are adapted for very large diameter pipes (>14 inches), then flow measurement capability is achieved, but the size and weight of the flowmeter become excessively large and massive
Solution Approach 1:
The flowmeter is nested within the existing large diameter pipe, with the measurement tube positioned inside the pipe interior. This allows the flowmeter to utilize the space within the pipe rather than requiring external structures, thereby reducing overall size and weight while maintaining measurement capability for large diameter pipes.
2Measurement precision
If blocking orifices or fluid blocking structures are inserted to enable flow measurement, then mass or volumetric flow can be measured, but downstream pressure drop is induced which is largely unacceptable
Solution Approach 1:
The flow measurement function is extracted from the main pipe flow path by using a separate measurement tube that samples flow without blocking it. The measurement tube is positioned to capture flow characteristics without creating significant pressure drop, allowing accurate measurement while maintaining acceptable pressure levels downstream.
3Measurement precision
If pipe diameter is necked down to accommodate flowmeter, then flow measurement accuracy is improved, but additional pressure losses are created
Solution Approach 1:
The pipe interior is segmented into a measurement zone (with the measurement tube) and a flow passage zone. This segmentation allows the measurement function to be isolated in a dedicated tube while the main pipe flow path remains uninterrupted, enabling accurate measurement without creating pressure losses through necking down.
4Measurement precision
If Coriolis meters are scaled up to accommodate large diameter pipes, then flow measurement accuracy of 0.1% or better is achieved, but the devices become exceedingly expensive and massive
Solution Approach 1:
The Coriolis measurement tube is nested within the large diameter pipe, allowing the use of small-diameter, high-accuracy Coriolis technology inside a large pipe. This nesting approach enables 0.1% or better measurement accuracy while avoiding the need to scale up the entire Coriolis meter, thereby reducing size and complexity.
Data Source
AI summary
An in-line flowmeter for large diameter pipes includes an outer pipe with a diameter equal to that of the pipe to which it is coupled and an inner measuring tube carrying a portion of the flow, the flow through the measuring tube being sensed by a flowmeter associated with the measuring tube and with the total combined flow rate out of the in-line flowmeter calculated from the sensed flow through the measuring tube.