Spool Valve Design for Semiconductor Chemical Handling
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Solution Overview
Problem
Existing spool valves for handling toxic and chemically aggressive substances in semiconductor manufacturing face challenges such as high manufacturing costs, internal dead space leading to contamination risks, and confusing port connections, which increase the risk of leaks and cross-contamination.
Innovation Solution
A spool valve design with a cylindrical housing and axially movable spool featuring reduced annular grooves and a bypass structure, made from chemically resistant materials like PFA or FFKM, with distinct port configurations to prevent misconnection and minimize dead space, ensuring secure sealing and efficient flushing with protective gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spool valve with multiple annular grooves and bypass passageways is used to prevent contamination and enable flushing, then reliability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The valve spool is segmented into multiple functional zones with distinct annular grooves (first, second, and third grooves) that separate product flow paths from protective gas flow paths. This segmentation prevents contamination by ensuring that product and protective gas do not mix within the valve internal passages.
Solution Approach 2:
The bypass passageway acts as an intermediary pathway that allows protective gas to flow through the valve body independently of the product flow path. This intermediary channel enables flushing of the product withdrawal line while maintaining separation between product and protective gas streams, preventing contamination.
2Reliability
If a spool valve with bypass passageway and multiple grooves is used to enable protective gas flushing, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The valve design merges the product transfer function and protective gas flushing function into a single integrated spool valve body. The bypass passageway is formed as an integral part of the valve housing, combining multiple functions (product flow control, protective gas flow control, and line flushing) into one component, which reduces the need for additional separate flushing valves or passages.
Solution Approach 2:
The spool valve serves multiple functions: it controls product flow between containers, enables protective gas injection into containers, and provides flushing capability for product withdrawal lines. The third annular groove and bypass passageway enable the valve to perform both product transfer and line flushing operations, making it a universal component for hazardous material handling.
3Object-affected harmful factors
If internal dead space is reduced in the valve, then contamination risk is minimized, but device complexity increases
Solution Approach 1:
The design extracts and eliminates internal dead space volumes from the valve structure. The bypass passageway is configured to minimize stagnant zones, and the annular grooves are positioned to ensure complete flow through all internal passages during operation and flushing cycles, preventing product accumulation in dead spaces that could lead to contamination or reactions.
Solution Approach 2:
The valve internal geometry is optimized by changing parameters such as passage cross-sectional areas, lengths, and configurations to minimize dead space volumes. The bypass passageway and annular grooves are dimensioned and positioned to maintain adequate flow velocities that prevent product stagnation, thereby reducing contamination risk through parameter optimization rather than adding complex active components.
4Ease of operation
If port configurations are made distinct to prevent misconnection, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The valve ports are configured with asymmetric characteristics that make them visually and physically distinct. The first and second bottom ports have different configurations or positions relative to the spool grooves, and the side ports are arranged asymmetrically to prevent incorrect connections. This asymmetry provides intuitive guidance for proper connection without requiring complex labeling or identification systems.
Data Source
AI summary
A valve has a housing defining a bore. Two bottom ports and two side ports in the housing communicate with the bore. Two annular grooves are in the outer surface of a spool received in the bore. A bypass extends within the spool from an annular groove to a bypass port. In one embodiment, the bore extends only partially through the housing and the bypass port is at an end of the spool. In another embodiment, the bypass port is on the outer cylindrical surface of the spool at a location substantially devoid of annular grooves therein. An actuator permits selective movement of the spool within the bore between a first position in which the first bottom port communicates with the first side port and the second bottom port communicates with the second side port and a second position, in which the first and second bottom ports communicate with each other and the first and second side ports communicate with each other. The valve has reduced dead space, making it desirable for use with aggressive chemical products.