Biosafety cabinet with divided plenum
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Solution Overview
Problem
Conventional biosafety cabinets with a single plenum require high blower speeds to overcome the pressure drop of filters, leading to increased power consumption, noise, and reduced filter life due to unbalanced airflow through supply and exhaust filters.
Innovation Solution
A biosafety cabinet with a divided plenum that separates airflow into independent supply and exhaust passageways, allowing the blower to operate at a lower speed by adjusting the divider to balance airflow rates independently of filter resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single plenum is used with both supply and exhaust filters, then the cabinet structure is simpler, but the blower must operate at high speed to overcome the pressure drop of the highest resistance filter, increasing power consumption and noise
Solution Approach 1:
The single plenum is divided into two separate plenums: a supply plenum for the supply filter and an exhaust plenum for the exhaust filter. This segmentation allows independent airflow paths, so the blower only needs to overcome the pressure drop of one filter at a time rather than the combined resistance, reducing power consumption and noise while maintaining containment effectiveness.
2Device complexity
If a single plenum is used with both filters, then the structure is simpler, but airflow through the filters becomes unbalanced due to different filter resistances, reducing system efficiency
Solution Approach 1:
By segmenting the plenum into separate supply and exhaust sections with independent airflow paths, each filter operates at its optimal airflow rate without being constrained by the other filter's resistance. This eliminates the airflow imbalance problem while maintaining structural simplicity through the use of a single blower unit.
3Productivity
If high blower speed is used to overcome filter pressure drop, then sufficient airflow through filters is achieved, but filter life is reduced due to increased stress and unbalanced airflow
Solution Approach 1:
The segmented plenum design allows the blower to operate at lower speeds since it only needs to overcome the pressure drop of one filter at a time. This reduced operating speed decreases mechanical stress on the filters and prevents premature loading, thereby extending filter life while maintaining adequate airflow for effective containment.
4Reliability
If high blower speed is used to maintain airflow through filters, then containment effectiveness is ensured, but noise level increases
Solution Approach 1:
By dividing the airflow path into separate supply and exhaust plenums, the blower operates at lower speeds to overcome individual filter resistances rather than combined resistance. This segmentation maintains the necessary airflow rates for effective containment while significantly reducing the noise generated by the blower motor.
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
Reduces power consumption and noise while extending filter life by optimizing airflow through separate filters, maintaining efficient containment and sterility in the work area.
Implementation Method 1
A blower is provided in the biosafety cabinet to pressurize a supply plenum and an exhaust plenum
Implementation Method 2
A supply filter is provided in the supply plenum. An exhaust filter is provided in the exhaust plenum
Data Source
AI summary
A biosafety cabinet including a plenum and a divider positioned in the plenum. The divider divides the plenum into a supply section and an exhaust section. A blower is positioned adjacent the plenum and in fluid communication with the plenum. The blower is configured to simultaneously supply air to both the supply section and the exhaust section of the plenum. An exhaust filter is positioned between the exhaust section and an exhaust outlet. The air supplied to the exhaust section from the blower passes through the exhaust filter. A supply filter is positioned between the supply section and a work area. The air supplied to the supply section from the blower passes through the supply filter. An adjuster may be coupled to the divider to adjust a position of the divider in the plenum.