Expandable Gate Valve for High-Temperature Vacuum Sealing
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Solution Overview
Problem
Conventional valves used in Czochralski processes face challenges in sealing at high temperatures and minimizing particulate generation, with existing seals failing under heat and generating contaminants due to mechanical movements.
Innovation Solution
A pendulum or shuttle gate valve with an axially expandable gate that moves transversely to seal the passageway, using compression springs and pneumatic pressure to ensure vacuum sealing, and incorporating a liquid-cooled valve plate and abutment member to protect against heat and contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional seals are used in high temperature processing chambers, then the valve can operate at elevated temperatures, but the seals fail under heat and generate particulate contaminants
Solution Approach 1:
The patent removes conventional seals from the high-temperature environment by implementing a seal-less valve design. The gate valve uses a gate that moves laterally to block the passageway without requiring seals to contact hot surfaces, thereby extracting the sealing function from the thermal environment where it would fail.
Solution Approach 2:
The patent introduces liquid cooling as an intermediary mechanism between the hot processing chamber and the valve components. Water or other cooling liquids circulate through channels in the gate and valve body, creating a thermal barrier that protects sealing surfaces from direct exposure to high temperatures while maintaining operational integrity.
2Reliability
If mechanical sealing movements are used to seal the passageway, then the valve can form a vacuum seal, but mechanical movements generate particulate contaminants
Solution Approach 1:
The patent replaces conventional mechanical sealing mechanisms that generate particles through friction and contact with a lateral movement gate system. The gate moves perpendicular to the passageway axis to block flow without sliding contacts, eliminating the mechanical wear and particulate generation associated with traditional seal designs.
Solution Approach 2:
The gate is divided into multiple segments or sections that can move independently or in coordination. This segmentation allows the gate to effectively block the passageway while reducing the complexity of mechanical connections and minimizing sources of particulate contamination from mechanical joints and fasteners.
3Area of stationary object
If a large valve is used to allow passage of large equipment, then the passageway can accommodate large workpieces, but the valve occupies valuable space in the processing chamber
Solution Approach 1:
The patent transitions from axial valve movement (occupying vertical space) to lateral gate movement (occupying horizontal space). The gate moves perpendicular to the passageway axis in a lateral direction, allowing the valve to be positioned in the side wall of the processing chamber rather than occupying valuable vertical space within the chamber, thereby accommodating large workpieces without compromising chamber volume.
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 valve provides reliable high-temperature sealing with minimal particulate generation, maintaining a vacuum seal even during power or pneumatic failures, and can be adapted for various Czochralski processes without significant contamination.
Implementation Method 1
incorporating a liquid-cooled valve plate and abutment member to protect against heat and contaminants
Implementation Method 2
using compression springs and pneumatic pressure to ensure vacuum sealing
Data Source
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AI summary
A pendulum gate valve (10) including an expandable gate (12) which pivots when unexpanded to selectively block a vacuum or other pressure-differential passage (20). The valve includes a valve plate (56) sealing one side of the passage and a ring (88) or barrier plate (154) abutting an opposed side of the passage when the gate member is expanded. A compression spring (106) biases apart the valve plate and ring to close the valve by means of respective two-stage hangers attached thereto, extending along the spring, and having distal ends capturing the spring. Pneumatic pressure (116) applied to a pneumatic cavity (114) formed between the middles of the two-stage hangers (66, 102) and accommodating the spring forces apart the valve plate and ring to open the valve in the blocking position. Thereby if pressure fails, the valve fails to a sealed state. The axially movable valve or barrier plate is advantageously water cooled (60) to allow use with a heated processing chamber.