Liquid Ring Pump for Corrosive Gas Evacuation
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Solution Overview
Problem
Conventional systems for evacuating corrosive effluent gas streams from processing chambers face issues such as toxic by-product generation, particulate accumulation, flammability concerns, and inefficient abatement due to temperature and pH dependencies, leading to increased costs and complexity.
Innovation Solution
A system incorporating a dry pumping arrangement followed by a liquid ring pump that dissolves corrosive fluids into its service liquid, a separator to remove the liquid, and an abatement arrangement, with the liquid ring pump installed vertically to manage particulates and flammability, and a flame arrestor to prevent ignition, reducing the load on downstream treatment systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a wet scrubber is used to scrub fluorine from effluent gas, then fluorine removal efficiency is improved, but toxic oxygen difluoride (OF2) by-product is generated at low temperatures and high pH values
Solution Approach 1:
The patent changes the chemical parameters of the scrubbing liquid by using alkaline earth metal hydroxides (such as calcium hydroxide, strontium hydroxide, or barium hydroxide) instead of conventional sodium hydroxide. This parameter change in the scrubbing agent's chemical composition allows for efficient fluorine removal while suppressing the formation of toxic OF2 by-products, resolving the contradiction between removal efficiency and harmful by-product generation.
2Object-affected harmful factors
If a dry pump is used to evacuate effluent gas, then lubricant contamination of the processing chamber is prevented, but particulate accumulation and seizure risk increase in the pump
Solution Approach 1:
The patent extracts the problematic dry pumping function from the system by replacing it with a liquid ring pump. This extraction of the dry pump eliminates the lubricant contamination issue while the liquid ring pump's design (with liquid sealing instead of tight mechanical clearances) inherently prevents particulate accumulation and seizure, thus resolving the reliability contradiction.
Solution Approach 2:
The patent applies hydraulic principles by using a liquid ring pump instead of a mechanical dry pump. The liquid ring creates a seal that prevents direct contact between moving parts and particulates, using fluid dynamics rather than mechanical clearance sealing. This hydraulic approach maintains the benefit of no lubricant contamination while eliminating the seizure risk associated with mechanical dry pumps.
3Reliability
If the liquid ring pump is installed in vertical orientation with downward gas inlet, then particulate accumulation in the pump is reduced, but the system complexity increases
Solution Approach 1:
The patent applies the principle of equipotentiality by orienting the gas inlet downward in the vertical configuration, allowing particulates to settle under gravity into the liquid ring where they are captured. This gravitational equipotential alignment simplifies the particulate removal mechanism without requiring additional complex components, resolving the contradiction between reliability improvement and system complexity.
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 configuration effectively reduces toxic by-product formation, minimizes particulate accumulation, and safely handles flammable gases, enhancing the efficiency and reliability of the abatement process while reducing operational costs.
Implementation Method 1
a liquid ring pump arranged for evacuating the gas stream comprising a corrosive fluid from the dry pump and at least partially reducing the corrosive fluid content of the gas stream by dissolving said corrosive fluid into the service liquid of the liquid ring pump
Implementation Method 2
a separator for separating, from the service liquid and remaining gas stream mixture exhausted from the liquid ring pump, the remaining gas stream
Data Source
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AI summary
Dry pumps are used to pump a variety of gas mixtures from the semiconductor industry. The present invention provides a liquid ring pump located between the dry pump and an abatement device to remove soluble corrosive materials prior to the exhaust gases entry to the abatement device, the work fluid exhausted from the liquid ring pump being separated from the gas prior to entry to the abatement device.