Butterfly Valve Rod Sealing With Magnetic Fluid for Vacuum Durability
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Solution Overview
Problem
Conventional butterfly valves in semiconductor manufacturing lack durability, leading to imperfect sealing and contamination due to the limited lifespan of O-rings, which results in frequent replacements and reduced manufacturing efficiency.
Innovation Solution
A butterfly valve design featuring a magnetic fluid seal, where a cylindrical magnetic member covers the rod and magnetic fluid is held in the void between the magnetic member and the hollow part, providing a durable seal resistant to multiple rotations and preventing process gas leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an O-ring is arranged on the rod to seal the insertion through hole, then sealing against process gas leakage is achieved, but durability is insufficient for several ten million rotations
Solution Approach 1:
The patent replaces the mechanical O-ring sealing system with a magnetic fluid sealing system. The magnetic fluid is held in position by magnetic force from the magnetic member, creating a seal that can withstand several ten million rotations without deteriorating, thus resolving the contradiction between sealing reliability and operational life.
Solution Approach 2:
The patent introduces magnetic fluid as an intermediary substance between the rod and the insertion through hole. This magnetic fluid, held by magnetic force, serves as the sealing medium that prevents process gas leakage while withstanding extensive rotational operations, overcoming the limitations of direct mechanical contact seals.
2Ease of manufacture
If the O-ring sealing deteriorates in a short period, then the butterfly valve must be replaced frequently, but this lowers semiconductor manufacturing efficiency
Solution Approach 1:
By replacing the mechanical O-ring system with a magnetic fluid sealing system, the patent eliminates frequent seal deterioration and replacement needs. The magnetic fluid seal maintains its sealing capability over several ten million rotations, thereby preventing manufacturing interruptions and maintaining high semiconductor manufacturing efficiency.
3Object-affected harmful factors
If process gas flows out from the butterfly valve due to imperfect sealing, then outside air contamination occurs, but frequent replacements are needed to prevent this
Solution Approach 1:
The patent replaces the deteriorating mechanical O-ring seal with a durable magnetic fluid seal that prevents process gas leakage over several ten million rotations. This eliminates the source of outside air contamination while maintaining extended operational life without frequent replacements.
Solution Approach 2:
The magnetic fluid acts as an intermediary sealing medium that reliably prevents process gas from escaping through the insertion through hole. This magnetic barrier maintains vacuum integrity and prevents outside air contamination throughout the extended operational life of the butterfly valve.
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 magnetic fluid seal enhances the durability of the butterfly valve, preventing outside air contamination and extending its operational life, thus improving semiconductor manufacturing efficiency by maintaining a reliable vacuum environment.
Implementation Method 1
the magnetic fluid is held by the magnetic force of the magnetic member, forming a so-called magnetic fluid seal
Data Source
AI summary
A butterfly valve includes a drive unit and a valve unit that are coupled to each other. The drive unit includes a hollow part in which a rod is inserted between a DD motor and an end portion of the drive unit on a coupling side to the valve unit. In the hollow part, a cylindrical magnetic member is placed coaxially with the rod to cover the outer peripheral surface of the rod. A magnetic fluid is filled in a void between the outer peripheral surface of the magnetic member and the inner peripheral surface of the hollow part. The rod is made of a non-magnetic corrosion-resistant alloy.