Portable Air Sampler with Feedback Flow Control
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Solution Overview
Problem
Existing air sampling devices in clean rooms lack efficient control over air flow rates, which can lead to suboptimal sampling conditions and potential contamination of adjacent areas.
Innovation Solution
The air sampling device incorporates a housing with a top opening, a retaining assembly for a sampling device and atrium, a plenum, a mass flow meter, and a blower controlled by a controller that adjusts the blower speed based on detected flow rates to maintain a desired flow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If air sampling devices operate at constant fan speed, then the device structure is simple, but the air flow rate cannot be precisely controlled leading to suboptimal sampling conditions
Solution Approach 1:
The patent implements a feedback control system where a mass flow meter continuously measures the actual air flow rate and feeds this information back to a controller. The controller compares the measured flow rate with the desired flow rate and adjusts the blower speed accordingly to maintain precise flow control, thereby improving sampling accuracy.
Solution Approach 2:
The patent replaces the simple mechanical constant-speed fan system with an electronically controlled blower system that uses a mass flow meter and controller for precise flow rate management. This substitution of mechanical simplicity with electronic control enables accurate flow regulation while maintaining relatively simple device structure.
2Reliability
If air flow rate is not precisely controlled, then the device structure remains simple, but contamination of adjacent areas may occur
Solution Approach 1:
The feedback control system continuously monitors air flow rate through the mass flow meter and adjusts the blower speed to maintain the desired flow rate. This ensures reliable prevention of contamination by maintaining optimal sampling conditions that prevent airborne contaminants from escaping the clean room environment.
Solution Approach 2:
The system dynamically changes the blower speed parameter based on real-time flow rate measurements to maintain the desired operating conditions. This parameter adjustment ensures that air flow remains within the optimal range for contamination prevention while adapting to varying system conditions.
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 solution ensures precise control over air flow rates within clean rooms, enhancing the accuracy of air sampling and preventing contamination by maintaining optimal sampling conditions.
Implementation Method 1
A mass flow meter has an input and an output, with the input coupled to the bottom end of the plenum and in flow communication with the bottom end of the plenum
Implementation Method 2
A blower is located inside the plenum and is configured to draw air past the sampling device, through the opening, through the plenum, and through the mass flow meter
Data Source
AI summary
An air sampling device and method of sampling air. The device has a housing body and a retaining assembly for a sampling device. A plenum has a top end coupled to the housing body about an opening such that the plenum is in flow communication with the opening and receives air flow generally from the top end to the bottom end generally along the longitudinal length thereof. A flow connection is coupled to the bottom end of the plenum. A mass flow meter has an input coupled to the flow connection and is in flow communication with the plenum via the flow connection. A blower is configured to draw air past the sampling device, through the opening, and through the plenum, such that a measuring portion of the air flows through the flow connection and through the mass flow meter, which measured the flow rate of the measuring portion.