System, computer program implemented product and method for operating a ductless fume hood
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Solution Overview
Problem
Ductless fume hoods face challenges in reliable filter monitoring due to arbitrary timer-based alarms, which do not account for actual usage, leading to potential toxic gas breakthroughs and inefficient filter change schedules, especially with odorless compounds, necessitating improved methods for ensuring safety and compliance with OSHA limits.
Innovation Solution
A system incorporating real-time gas level monitoring using electronic devices and software, including a PID detector, set measure mode for absolute ppm readings, and interfilter monitoring, which allows for precise determination of filter saturation and estimated remaining filter life, eliminating the need for frequent and arbitrary filter checks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If timer-based alarms are used to notify filter replacement, then the system is simple to operate, but the reliability of filter monitoring deteriorates because arbitrary alarms do not coincide with actual filter saturation timing
Solution Approach 1:
The patent replaces the mechanical timer-based alarm system with an electronic sensor-based monitoring system. Gas sensors continuously detect contaminant concentrations in the exhaust air, and an electronic control system processes this data to determine when filter replacement is actually needed, substituting arbitrary time-based notifications with evidence-based real-time monitoring.
Solution Approach 2:
The system implements feedback by continuously measuring the actual gas concentrations in the exhaust air and using this information to adjust the filter replacement timing. The sensors provide real-time feedback on filter performance, allowing the system to notify users based on actual saturation conditions rather than predetermined time intervals.
2Device complexity
If users wait for detectable odor to check filter condition, then the monitoring approach is simple, but safety deteriorates because toxic gas concentrations may already exceed OSHA limits
Solution Approach 1:
The patent replaces human sensory detection (olfaction) with electronic gas sensors that can detect toxic compounds at concentrations far below odor thresholds and OSHA limits. These sensors provide objective, quantitative measurements of gas concentrations, eliminating the subjective and delayed nature of odor-based detection.
Solution Approach 2:
The system introduces gas sensors as an intermediary between the toxic chemicals and the user. Instead of users directly sensing gases through their senses, the sensors act as intermediaries that detect and communicate gas concentrations, providing early warning before hazardous levels are reached.
3Adaptability or versatility
If broad range gas sensors are used to detect exhaust concentration, then the device can detect multiple compounds, but measurement precision deteriorates because sensors have widely varied sensitivity to different gases making it difficult to correlate readings to actual concentrations
Solution Approach 1:
The system addresses sensor sensitivity variations by changing the reference parameter from absolute concentration readings to relative change measurements. By monitoring the change in sensor output over time and comparing it to baseline values, the system can detect filter saturation trends even when absolute concentration correlations are uncertain. The patent also incorporates a database of chemical properties to adjust interpretations based on the specific compounds being used.
Solution Approach 2:
The system creates a digital model or copy of the expected sensor response patterns for different gases and conditions. By comparing actual sensor readings against these reference patterns stored in a database, the system can identify and compensate for sensitivity variations, improving the accuracy of concentration estimates across multiple compound types.
4Object-generated harmful factors
If activated carbon filters are used for filtration, then the filtration system is effective at removing chemical vapors, but the filter eventually becomes saturated causing harmful breakthrough
Solution Approach 1:
The system implements continuous feedback monitoring of the filter's performance by measuring gas concentrations in the exhaust air. When the sensor detects that contaminant levels are approaching or exceeding safe thresholds, the system provides feedback to alert users that the filter is nearing saturation and needs replacement, optimizing the filter service life based on actual usage conditions.
Solution Approach 2:
The system performs preliminary detection of filter saturation trends before actual breakthrough occurs. By continuously monitoring exhaust concentrations and detecting gradual increases that indicate approaching saturation, the system enables proactive filter replacement before harmful levels are reached, extending the effective service life of the filter while ensuring safety.
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 reliable and timely filter monitoring, reducing the risk of toxic gas exposure by providing accurate, real-time data on gas concentrations and filter efficiency, thereby enhancing safety and compliance with safety regulations without unnecessary disruptions.
Implementation Method 1
a PID detector, set measure mode for absolute ppm readings
Data Source
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AI summary
System for a ductless fume hood (100) comprising a ductless fume hood (100) including a hood enclosure; two or more detectors comprising a photo-ionization detector (PID) sensor and at least one of a metal oxide detector (MOX) or an acid array sensor; the system also comprising a motor (102) which draws an effluent stream (C) of contaminated air through the hood enclosure; at least one chemical removal filter (106) for egress at an exhaust stack (118) and a processor operatively coupled a control panel (120) and configured to determine, in response to a user selection of at least one chemical species from a plurality of chemical species included in a chemical database, the at least one chemical removal filter capable of removing the selected chemical species from the effluent stream of contaminated air.