Normally-Closed Flow Control Valve With Thermal-Stable Piezo Actuation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing normally-closed flow rate control valves using piezoelectric elements face challenges in precisely transmitting length changes without thermal influence and adjusting pressing forces effectively, leading to potential liquid leakage or damage due to inadequate thermal insulation and spring adjustment.
Innovation Solution
A normally-closed flow rate control valve design featuring a low thermal expansion support post and a cooling structure with a cooling fin, along with an elastic member for adjustable pressing force, ensures precise transmission of piezoelectric element expansion and minimizes thermal influence, while a protective plate and steel ball configuration prevents diaphragm damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a general metal member (e.g., stainless steel) is used for the valve rod and circular cylindrical member, then the structure is simple and easy to manufacture, but thermal expansion occurs when heat is transferred, causing the length to change and preventing precise transmission of the piezoelectric element's length change
Solution Approach 1:
The patent changes the material parameter (thermal expansion coefficient) of the valve rod and circular cylindrical member by selecting a low thermal expansion material such as Invar alloy. This material has a thermal expansion coefficient close to zero, allowing the length to remain substantially constant even when heat is transferred from the valve body or surroundings, thereby enabling precise transmission of the piezoelectric element's length change without thermal interference.
2Reliability
If the pressing force from the diaphragm to the valve seat is increased, then liquid leakage is prevented, but the valve seat may be damaged
Solution Approach 1:
The patent introduces an adjustable pressing spring mechanism that allows the pressing force from the diaphragm to the valve seat to be dynamically optimized. The pressing spring can be adjusted to provide sufficient closing force to prevent liquid leakage while avoiding excessive force that could damage the valve seat. This creates a balanced,可调 system that adapts to the specific operational requirements.
3Reliability
If a normally-opened valve configuration is used, then the valve is simple to operate, but when power failure or piezoelectric actuator malfunction occurs, liquid raw material is supplied to the vaporizing chamber causing semiconductor wafer damage
Solution Approach 1:
The patent inverts the conventional valve configuration from normally-opened to normally-closed. In this inverted configuration, the valve is closed by default (when no voltage is applied to the piezoelectric element), and opens only when voltage is applied. This ensures that in case of power failure or piezoelectric actuator malfunction, the valve remains closed and prevents liquid raw material from being supplied to the vaporizing chamber, thereby protecting semiconductor wafers from damage.
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 precise and quick valve operation with reduced thermal errors and optimal pressing force adjustment, preventing liquid leakage and damage, thereby ensuring reliable operation in semiconductor manufacturing.
Implementation Method 1
a piezoelectric element that expands by application of voltage, and presses up the support post part in such a direction as to separate the support post part from the diaphragm
Implementation Method 2
at least one of a cooling space and a cooling fin is disposed in the base block upper part
Implementation Method 3
thermal expansions of the valve rod for transmitting the change in length of the piezoelectric element and the circular cylindrical member including the valve rod therein are extremely important
Data Source
AI summary
A flow rate control valve includes a base block and a valve opening/closing mechanism. The base block is provided with a valve chamber in which a valve seat through which a liquid raw material L flows, and a diaphragm that is brought into contact with or separated from the valve seat so as to close/open the valve seat are installed. The valve opening/closing mechanism includes a slide bearing part, a support post part, a piezoelectric actuator part, and a valve-actuating part. The slide bearing part is installed on the base block 1 and is provided with a bearing. The support post part includes a support post that is inserted slidably in the bearing and that moves upward and downward in a diaphragm direction.