Vacuum Valve Piston Packing for Sliding Resistance
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Solution Overview
Problem
Conventional vacuum valves face challenges in achieving compact size, cost-effectiveness, and accurate control of valve opening degree due to increased size and sliding resistance issues, particularly in semiconductor manufacturing where a compact and inexpensive solution with good controllability is required.
Innovation Solution
A vacuum valve design featuring a piston with an annular recessed groove housing an annular packing with a contact portion and a slide-contact portion, allowing flexible deformation to minimize sliding resistance and achieve precise control of valve opening degree without additional sensors, combined with an electropneumatic regulator for precise pressure control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bellofram is used to hermetically close the space between piston and cylinder, then sealing performance and response are improved, but valve size increases and cost increases
Solution Approach 1:
The patent extracts the bellofram component from the valve structure and replaces it with a simpler O-ring sealing system. The O-ring is mounted in a groove on the piston's outer peripheral surface, eliminating the need for the bulky bellofram bellows while maintaining hermetic sealing between the piston and cylinder during piston movement.
Solution Approach 2:
The patent replaces the expensive bellofram component with a more economical O-ring sealing solution. The O-ring is a simpler, cheaper component that can be easily replaced if needed, reducing both the initial cost of the valve and the cost of maintenance while providing adequate sealing performance.
2Ease of manufacture
If an O-ring is mounted in a recessed groove on the piston, then manufacturing is simplified, but sliding resistance increases reducing control accuracy
Solution Approach 1:
The patent introduces a potentiometer to dynamically measure the actual valve opening degree and provides feedback to the control system. This dynamic measurement and feedback mechanism compensates for the sliding resistance caused by the O-ring, allowing the system to maintain accurate control of the valve opening degree despite the friction present in the O-ring sealed configuration.
3Speed
If sliding resistance is reduced using a bellofram, then hysteresis is reduced and response is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces a potentiometer as an intermediary measurement device that detects the valve opening degree. This intermediary component provides feedback information to the control system, enabling precise control of the valve opening degree without requiring a bellofram. The potentiometer acts as a mediator between the mechanical valve position and the electronic control system, achieving accurate control through information feedback rather than mechanical friction reduction.
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 solution enables a compact, cost-effective vacuum valve with improved controllability and response, capable of accurately adjusting valve opening degree based on operating pressure, reducing hysteresis and the need for feedback control, thus enhancing vacuum pressure control systems.
Implementation Method 1
the slide-contact portion is flexibly deformed with respect to the contact portion
Implementation Method 2
control operating pressure acting on the piston by supply and exhaust of the operating fluid with respect to the cylinder to adjust a valve opening degree
Data Source
AI summary
A vacuum valve placed between a vacuum vessel and a vacuum pump to adjust a valve opening degree using an operating fluid includes a packing mounted in a recessed groove of a piston. The packing is provided with a contact portion on a radially inner side and a contact portion on a radially outer side, and a slide-contact portion contacting with an inner peripheral surface of a cylinder. A portion between the contact portion and the slide-contact portion has a thin thickness.