Curved Inlet Cone Pressure Sensing for FC Fan Airflow Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Determining the volume airflow rate through a centrifugal fan is challenging due to varying air velocities, which can be disrupted by pressure taps, and existing methods require multiple pressure taps to measure pressure drops, causing flow restrictions.
Innovation Solution
A system using a single pressure sensor to measure the static pressure at a curved inlet cone, allowing for accurate airflow volume determination without creating an undesirable pressure drop or flow obstruction, and incorporating a static pressure receiver within the discharge air chamber for protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure taps are inserted across the flow path to integrate air velocity profile, then measurement precision is improved, but flow obstruction increases
Solution Approach 1:
A curved inlet cone is introduced as an intermediary component that redirects airflow to create a controlled low-pressure zone. This mediator allows pressure measurement without requiring direct insertion of multiple taps into the main flow path, thus maintaining flow while enabling accurate measurement through a single tap positioned at the cone's apex.
Solution Approach 2:
The system changes the measurement parameter from direct velocity profile integration to static pressure measurement at a specific location. By measuring the static pressure at the apex of the curved inlet cone where airflow velocity is maximized and pressure is minimized, the system determines total airflow volume through a different physical relationship that avoids flow obstruction.
2Measurement precision
If multiple pressure taps are used to sense pressure drop across flow restriction, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The invention extracts the measurement function from multiple distributed pressure taps and concentrates it into a single pressure tap located at the apex of the curved inlet cone. This single tap captures the critical pressure information needed to determine total airflow, eliminating the need for complex arrays of multiple taps while maintaining measurement capability.
Solution Approach 2:
The curved inlet cone structure serves multiple functions: it redirects airflow to create a measurable low-pressure zone, protects the pressure tap from direct exposure to high-velocity flow, and enables single-point measurement that represents the overall airflow condition. This multi-functional component simplifies the measurement system while maintaining accuracy.
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
Enables accurate and efficient measurement of airflow volume through a centrifugal fan using a single pressure sensor, maintaining minimal pressure drop and flow obstruction, and accommodating variable conditions such as fan speed and geometry, while protecting the pressure sensor.
Implementation Method 1
A pressure sensor connected in fluid communication with the static pressure receiver is responsive to a static gage pressure of the suction air to provide a pressure signal indicative of the static gage pressure of the suction air at the minor diameter
Data Source
AI summary
An airflow volume sensing system for determining the flow rate through a fan includes a curved inlet cone with a pressure sensor at the minimum diameter of the cone, wherein the flow volume sensing system is particularly suited for FC centrifugal fans (centrifugal fans with forward curved fan blades). With an FC fan, the minimum diameter of the inlet cones interior surface is adjacent the fan wheel, and the static pressure there is at a minimum value. A predetermined relationship between the static gage pressure at that point and the volume flow rate through the fan is applied regardless of variables such as fan speed, fan housing geometry, supply air duct configurations, return air duct configurations, location of various heat exchangers or filters, etc. In some examples, a single pressure sensor senses an average of a plurality of pressure taps wherein each tap is at approximately the same minimum pressure.