Butterfly Valve Balance Layout for High-Speed Vacuum Control
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Solution Overview
Problem
The existing butterfly valve designs in semiconductor manufacturing processes experience misalignment of the rotary central axis due to centrifugal force, leading to excessive load on ball bearings and interference with the passage inner wall, which reduces the valve's life expectancy, especially with the accelerated vacuum pressure control required by Atomic Layer Deposition methods.
Innovation Solution
The butterfly valve is configured with a joint-body gravity center positioned on the axis of the rotary shaft, where the constituent-component gravity centers are balanced to minimize centrifugal force, using a direct drive motor and a joint body formed by fixing the butterfly valve element to the rod with screws or rivets, and the rod is journaled in a both-ends-supported state by pre-compressed ball bearings to stabilize the axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the butterfly valve element is joined to the rod with eccentric placement to enable rotation, then the valve can open and close the passage, but centrifugal force causes misalignment of the rotary central axis leading to ball bearing damage and reduced reliability
Solution Approach 1:
A counterweight is attached to the rod at a position opposite to the butterfly valve element's gravity center relative to the rotary central axis. The counterweight's mass and position are calculated to balance the gravitational moment, ensuring the combined gravity center of the rod and butterfly valve element coincides with the rotary central axis. This eliminates centrifugal force during rotation, preventing ball bearing damage and misalignment while maintaining smooth rotational operation.
2Productivity
If the rotation speed is increased to accelerate vacuum pressure control for ALD processes, then productivity improves, but centrifugal force increases causing greater misalignment and ball bearing damage
Solution Approach 1:
The counterweight balances the gravity center of the rotating assembly, eliminating centrifugal force-induced misalignment. This allows the system to operate at high rotation speeds required for accelerated vacuum pressure control in ALD processes without compromising ball bearing life or causing interference with the passage inner wall.
3Ease of manufacture
If the gravity center of the butterfly valve element is placed off-axis to simplify structure, then manufacturing is easier, but centrifugal force causes interference with the passage inner wall
Solution Approach 1:
The counterweight offsets the eccentric gravity center of the butterfly valve element, ensuring the combined gravity center aligns with the rotary central axis. This prevents centrifugal force from pushing the butterfly valve element against the passage inner wall during high-speed rotation, eliminating interference while maintaining the simple structural design.
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 reduces misalignment and load on ball bearings, preventing interference with the passage inner wall and enhancing the butterfly valve's life expectancy while enabling high-speed operation required for ALD processes.
Implementation Method 1
a gravity center of the joint body at least including the rod and the butterfly valve element as constituent components is positioned on an axis of a rotary shaft of the motor... a centrifugal force is generated when the rod is rotated to open and close a passage by the butterfly valve element
Data Source
AI summary
A butterfly valve has a rod connected to a DD motor and disposed along a direction orthogonal to a flow path, and a butterfly valve body that is linked to the rod and that opens and closes the flow path due to the rod being rotated by the DD motor, wherein a linking body center of gravity, which is the center of gravity of a rotating liking body having at least the rod and the butterfly valve body as constituent members, is positioned on an axial line of a rotating shaft of the DD motor.