Fan Intake Nozzle with Bypass Flow Insert for Volume Measurement
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Solution Overview
Problem
Conventional methods for determining volume flow in fans, especially centrifugal fans with backward-curved blades, lack accuracy and are costly due to non-linear relationships and high installation efforts, particularly at low volume flows.
Innovation Solution
An intake nozzle design with a detachable flow insert forming a bypass opening, equipped with hot-film anemometry and thermocouple sensors, and a confuser to accelerate and bundle the bypass flow, ensuring accurate volume flow measurement across all operating points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a ring main with pressure taps and hoses is used to measure volume flow in centrifugal fans, then volume flow rate can be determined from static pressure measurements, but the installation becomes complex and expensive
Solution Approach 1:
The measurement system is segmented into modular components: the ring main is integrated directly into the intake nozzle structure, pressure taps are built-in, and electronic pressure sensors replace external hose connections. This segmentation allows each component to be optimized independently while simplifying overall installation.
Solution Approach 2:
The ring main and pressure measurement system are merged with the intake nozzle structure itself, eliminating the need for separate external piping and hose connections. The pressure taps are integrated directly into the nozzle, combining the flow measurement function with the existing structural component.
2Ease of operation
If static pressure measurement is used to determine volume flow rate in centrifugal fans, then a measurement method is available, but the non-linear relationship between delivered volume flow and differential pressure significantly worsens measurement accuracy at small volume flow rates
Solution Approach 1:
The system uses electronic pressure sensors that can measure differential pressure with high precision across a wide range, including very small pressure differences at low flow rates. The measurement parameters are optimized to maintain linearity and accuracy across the entire operating range from zero to maximum flow.
Solution Approach 2:
Traditional mechanical pressure measurement systems are replaced with electronic pressure sensors that provide higher precision, better linearity, and improved accuracy at low differential pressures. The electronic system can detect and process very small pressure signals that would be difficult to measure with mechanical gauges.
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 provides precise volume flow measurement with minimal error and tolerance, even at low volume flows, by optimizing the flow path and sensor placement, enhancing measurement accuracy and reducing installation complexity.
Implementation Method 1
the confuser accelerates and focuses the bypass flow. The measuring instruments are positioned in the narrowest flow cross-section of the confuser
Implementation Method 2
Hot-film anemometry is preferably used for flow measurement, requiring evaluation electronics and two thermocouple sensors
Implementation Method 3
a PT100 and a PT1000 thermocouple, measuring the ambient temperature, are used as sensors
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
The invention relates to an intake nozzle and an exhaust unit for a fan, as well as the fan with an intake nozzle and an exhaust unit.