Vacuum Pump Exhaust Dilution for Flammable Gas Emissions
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Solution Overview
Problem
Vacuum pumping systems in semiconductor fabrication facilities face challenges in safely disposing of flammable gases like hydrogen, as burning these gases produces waste heat and requires additional fuel, increasing costs and environmental impact.
Innovation Solution
A vacuum pumping system that dilutes flammable gases with air to below their lower flammability limit, using a housing with distinct pressure regions and an air flow duct to mix air with the gas stream, ensuring safe emission without combustion, and incorporating sensors to monitor and control the air flow for effective dilution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If flammable gases are burned for disposal, then the gases are eliminated, but waste heat is produced and additional fuel is 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 air in controlled proportions. The flammable gas stream is mixed with air in a mixing region to achieve a concentration below the lower flammability limit, transforming a hazardous substance into a safe emissions stream without combustion.
Solution Approach 2:
The patent changes the concentration parameter of the flammable gas by introducing air flow at a controlled rate. The air flow generator supplies air at a rate sufficient to dilute the flammable gas to a concentration below its lower flammability limit, fundamentally altering the safety parameter of the gas stream from flammable to non-flammable.
2Object-generated harmful factors
If flammable gases are burned for disposal, then the gases are eliminated, but additional fuel gas is required, increasing operational costs
Solution Approach 1:
The system eliminates the need for fuel gas by using the flammable gas itself as the substance to be disposed of through dilution rather than combustion. The air flow generator provides the dilution medium, completely removing the requirement for additional fuel gas consumption.
Solution Approach 2:
Air acts as an intermediary substance that enables the safe disposal of flammable gas without requiring fuel gas. The air flow generator introduces air into the mixing region, where it serves as the medium that dilutes the flammable gas to safe concentrations for atmospheric discharge.
3Reliability
If air is introduced to dilute flammable gas, then safety is improved by reducing flammability, but the system complexity increases due to additional components
Solution Approach 1:
The patent merges the air flow generation and gas mixing functions into a single integrated housing structure. The housing contains both the vacuum pumping arrangements and the air flow duct with mixing region, combining multiple functions (vacuum pumping, air supply, mixing) into one unified system rather than separate components.
Solution Approach 2:
The housing serves multiple functions: it houses the vacuum pumping arrangements, forms the air flow duct, provides the mixing region, and contains the exhaust outlets. This multi-functional design reduces the number of separate components needed while maintaining safety through air dilution.
4Reliability
If mixing region is designed to ensure complete dilution, then safety is improved, but the housing volume increases
Solution Approach 1:
The patent creates a localized mixing region within the housing where air and flammable gas are thoroughly mixed. This focused mixing zone ensures complete dilution effectiveness in a specific area rather than requiring the entire housing to be large, maintaining compact overall dimensions while achieving safe mixing conditions.
Solution Approach 2:
The exhaust outlets are arranged to exhaust the gas stream in a direction generally transverse to the air flow, utilizing a different spatial dimension for exhaust discharge. This transverse arrangement optimizes mixing efficiency without requiring increased housing volume in the primary flow direction.
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 approach eliminates the need for fuel gases, reduces waste heat, and minimizes environmental impact by safely diluting flammable gases, making the system more robust, cost-effective, and environmentally friendly, while maintaining efficient pumping performance.
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 of the flammable gas
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 and exhausting the gas stream through one or more exhaust outlets; The housing may comprise a first region at lower pressure and a second region at higher pressure
Data Source
AI summary
A vacuum pumping system which comprises a plurality of vacuum pumping arrangements for evacuating a flammable gas stream and exhausting the gas stream through an exhaust outlet. A housing houses the vacuum pumping arrangements and forms an air flow duct for an air flow for mixing with the exhaust gas stream output from the exhaust outlet in a mixing region in the housing. An airflow generator 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 senses the flow of air for determining if the air flow is sufficient to dilute the flammable gas to lower than said percentage.