Centrifugal Fan Pressure Sensing for Accurate Airflow Control
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Solution Overview
Problem
Centrifugal fans in air conditioning apparatuses face challenges in rotation speed control due to smaller motor output variation, requiring accurate detection of primary-side pressure to maintain optimal airflow rates, which is difficult due to dynamic pressure interference.
Innovation Solution
The primary-side pressure detection tube of a pressure sensor is strategically positioned close to the circumferential part of the casing, away from dynamic pressure areas near the fan entrance, allowing for accurate pressure detection and subsequent rotation speed control of the centrifugal fan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the primary-side pressure detection tube is positioned near the fan opening on the inlet side surface of the bell mouth, then it is easier to access for pressure detection, but the detection accuracy deteriorates due to dynamic pressure interference
Solution Approach 1:
The partition member acts as an intermediary structure that separates the fan compartment from the heat exchanger compartment. The pressure detection tube is positioned on the heat exchanger compartment side of the partition member, using the partition as a mediator to access the primary-side pressure location while avoiding the dynamic pressure interference zone near the fan opening.
Solution Approach 2:
The invention applies local quality by specifically positioning the pressure detection tube at a location with different flow characteristics - on the heat exchanger compartment side of the partition member rather than directly near the fan opening. This local positioning change allows pressure detection away from the high dynamic pressure zone while maintaining accessibility.
2Productivity
If rotation speed control is implemented for the centrifugal fan, then airflow rate management improves, but the control accuracy deteriorates due to smaller motor output variation compared to sirocco fans
Solution Approach 1:
The invention implements feedback control by using the accurately detected primary-side pressure (obtained through the properly positioned pressure detection tube) as feedback information to adjust and control the centrifugal fan's rotation speed. This feedback mechanism compensates for the smaller motor output variation, enabling precise airflow rate management despite the centrifugal fan's characteristics.
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
This configuration enables precise detection of primary-side pressure, facilitating effective rotation speed control of the centrifugal fan, thereby improving airflow rate management and ventilation performance.
Implementation Method 1
a primary-side pressure detection tube of a pressure sensor for detecting a primary-side pressure of the centrifugal fan is opened in a position close to a circumferential part of the casing on an inlet side surface of the bell mouth
Data Source
AI summary
An air conditioning apparatus includes a centrifugal fan mounted in an interior of a casing and a pressure sensor. The pressure sensor can have a primary-side pressure detection tube opened in a position adjacent to a circumferential part of the casing on an inlet side surface of the bell mouth of the fan when the bell mouth is seen from a direction along the rotary shaft to detect a primary-side pressure of the centrifugal fan. Alternatively, the pressure sensor can have a primary-side pressure detection tube opened in a position adjacent to a circumferential part of the casing on a heat exchanger compartment side surface of the partition member when the partition member is seen from a direction along the rotary shaft to detect a primary-side pressure of the centrifugal fan.