Vacuum Pump Exhaust Air Dilution for Flammable Gas Discharge
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Solution Overview
Problem
Existing vacuum pumping systems in semiconductor fabrication facilities face challenges in safely evacuating flammable gases like hydrogen, as they often rely on combustion methods that produce waste heat and require fuel gases, increasing costs and environmental impact.
Innovation Solution
A vacuum pumping system that dilutes flammable gas streams with air to below the lower flammability limit using an air flow generator and sensor system, eliminating the need for combustion and reducing environmental impact by using ambient air for dilution, thereby avoiding the use of fuel gases and minimizing waste heat production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If combustion methods are used to evacuate flammable gases, then the gases can be effectively removed, but waste heat is produced and fuel gases are required, increasing costs and environmental impact
Solution Approach 1:
The patent converts the harmful flammable gas into a beneficial dilution medium by mixing it with exhaust air containing oxygen. The flammable process gas (e.g., hydrogen) is mixed with air from the exhaust outlets, creating a diluted mixture that is safely discharged. This eliminates the need for combustion and fuel gases, converting what was a hazard into the solution for safe disposal.
Solution Approach 2:
The patent introduces exhaust air as an intermediary medium between the flammable process gas and the atmosphere. The exhaust air, containing oxygen and other gases, serves as a mixing medium that dilutes the flammable gas to below its lower flammability limit, enabling safe discharge without combustion.
2Productivity
If combustion methods are used to evacuate flammable gases, then the gases can be effectively removed, but fuel gases are required, increasing operational costs
Solution Approach 1:
The system uses its own exhaust air as a resource to dilute and dispose of flammable gases. The exhaust air, which would otherwise be wasted, is recirculated and used as the dilution medium, making the system self-sufficient and eliminating the need for external fuel gases or additional chemical reagents.
3Device complexity
If flammable gas is discharged directly to atmosphere, then the system is simple, but the gas may be above the lower flammability limit, creating safety hazards
Solution Approach 1:
The patent merges the flammable process gas stream with the exhaust air stream in a mixing region. By combining these two flows, the system achieves dilution of the flammable gas to below its lower flammability limit, ensuring safe discharge while maintaining a relatively simple system architecture.
Solution Approach 2:
The system incorporates air flow sensors that provide feedback on the mixing process. The sensors monitor the air flow rate and the composition of the mixed gas, ensuring that the flammable gas is diluted to safe levels before discharge. This feedback mechanism maintains safety while allowing the system to operate efficiently.
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
The system effectively reduces the carbon footprint, eliminates the dependency on fuel gases, and ensures safe handling of flammable gases by diluting them to non-flammable concentrations, making it more environmentally friendly and cost-effective compared to traditional combustion-based methods.
Implementation Method 1
an air flow generator for generating an air flow through the air flow duct to cause mixing of air with the flammable gas stream to a percentage of the flammable gas in the air flow lower than the lower flammability limit
Implementation Method 2
an air flow sensor for sensing the flow of air for determining if the air flow is sufficient to dilute the flammable gas to lower than said percentage
Implementation Method 3
a plurality of vacuum pumping arrangements for evacuating a flammable gas stream
Data Source
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AI summary
The invention relates to a vacuum pumping system (10) which comprises a plurality of vacuum pumping arrangements (12, 14, 16) for evacuating a flammable gas stream and exhausting the gas stream through an exhaust outlet (78). A housing houses the vacuum pumping arrangements and forms an air flow duct for an air flow (70) for mixing with the exhaust gas stream output from the exhaust outlet in a mixing region (80) in the housing. An airflow generator (77) generates an air flow through the air flow duct to cause mixing of air with the flammable gas stream to a percentage of the flammable gas in the air flow lower than the lower flammability limit of the flammable gas. An airflow sensor (130) senses the flow of air for determing if the air flow is sufficient to dilute the flammable gas to lower than said percentage.