Hermetic Vacuum Pump Sealing for High-Purity Processing
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Solution Overview
Problem
Existing vacuum pumps and systems struggle to achieve high purity levels, such as parts per million (ppm) or parts per billion (ppb), in medium or crude vacuum environments due to back-streaming of air and contaminants, necessitating expensive pumping systems or brute force gas flow, which are costly and inefficient.
Innovation Solution
The use of a Peclet seal tube combined with a sweeping gas to prevent backflow of contaminants and ambient air, achieving high purity levels in vacuum processing chambers by isolating the pumping system from the ambient environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional vacuum pumps are used to evacuate the processing chamber, then medium or crude vacuum can be achieved, but high purity levels cannot be maintained due to back-streaming of air and contaminants
Solution Approach 1:
The system divides the vacuum pathway into separate segments: a first pumping system for rough vacuum and a second pumping system for high purity vacuum. Each pump handles a specific pressure range and purity requirement, preventing contaminants from one stage from affecting the other stage. The isolation valve separates these segments, allowing independent operation and maintenance.
Solution Approach 2:
An isolation valve is introduced as an intermediary component between the two pumping systems. This valve acts as a barrier that prevents back-streaming of contaminants from the first pump while allowing the second pump to maintain high purity vacuum. The valve mediates the interaction between the two systems, enabling each to perform its specific function without compromising the other.
2Quantity of substance
If multiple pumps are staged in series to achieve high purity, then purity levels can be improved, but system cost and complexity increase significantly
Solution Approach 1:
The vacuum system is segmented into two distinct pumping stages with clear functional divisions. The first pump handles rough vacuum evacuation while the second pump maintains high purity vacuum. This segmentation allows each component to be optimized for its specific function, reducing the need for overly complex single-stage systems while achieving the desired purity levels through coordinated operation of simpler individual components.
3Quantity of substance
If excessive gas flow is used to suppress back-streaming, then purity can be partially improved, but operational costs increase and the approach is still insufficient
Solution Approach 1:
The isolation valve serves as a mediator that blocks the back-streaming pathway, eliminating the need for excessive gas flow to suppress contamination. By physically isolating the high purity vacuum chamber from the rough vacuum pump, the system achieves high purity levels without wasting energy on excessive gas circulation, as the valve prevents contaminants from entering in the first place.
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 allows for remarkable purity levels to be achieved without the need for high-cost pumps, enabling successful sintering of metals like aluminum and other historically difficult materials, while maintaining low operational costs.
Implementation Method 1
tubing long in length relative to a cross-sectional area combined with an outflow through the tubing of a sweeping gas that prevents backflow of contaminants and ambient air through the tubing
Data Source
AI summary
Disclosed is a pumping system with reduced contamination. A vacuum pump system includes a mechanical vacuum pump mechanism within a hermetic pump that hermetically isolates the pump mechanism from ambient air. A pump inlet is hermetically scaled to the hermetic pump housing. A pump outlet is hermetically sealed at one end to the hermetic pump housing and at the other end to an inlet of a Peclet seal tube. The vacuum pump system produces a vacuum in a vacuum processing chamber. A sweep gas source injects a sweep gas into at least one of (i) the hermetic pump housing and (ii) the inlet of the Peclet seal tube. The sweep gas and a process gas flow through the Peclet seal tube to substantially isolate against the backflow of the ambient air through the Peclet seal tube.