Dual Spring Flow Control Valve for Precision Low-Flow Regulation
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Solution Overview
Problem
Current pneumatic flow control valves lack precision at lower flow rates, leading to imprecision and difficulty in controlling systems with wide flow and pressure swings, and often require two separate mechanical valves to achieve accurate control, which increases complexity and cost.
Innovation Solution
A dual-mode electropneumatic proportional flow control device utilizing a combination of linear and non-linear variable springs, where the linear spring handles initial valve actuation and the non-linear spring manages higher flow rates, enhancing turndown ratios and precision with improved electromagnetic response to control voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single conventional valve is used, then the device complexity is low, but the measurement precision at lower flow rates deteriorates
Solution Approach 1:
The valve is segmented into two distinct flow paths: a main flow path for high-volume flow and a bypass flow path with a needle valve for precision low-flow control. This segmentation allows each path to be optimized for its specific flow range, resolving the contradiction between simple structure and precise low-flow control.
Solution Approach 2:
A bypass flow path acts as an intermediary mechanism between the main flow path and the outlet. This bypass path with the needle valve provides precise control for low flow rates without requiring the main valve to have complex precision control mechanisms, thus maintaining overall structural simplicity while achieving high measurement precision at low flows.
2Measurement precision
If two separate mechanical valves are used in sequence, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The invention merges two valve functions into a single integrated structure: a main valve for high-volume flow control and a bypass needle valve for precision low-flow control. Both valves share a common body and outlet, eliminating the need for two separate mechanical valves while maintaining the precision benefits of having separate control paths for different flow ranges.
Solution Approach 2:
The single valve body serves multiple functions: it houses both the main flow path and the bypass flow path, provides sealing surfaces for both valves, and directs flow to a common outlet. This multi-functionality allows one valve structure to perform the work of two separate valves, reducing device complexity while maintaining measurement precision.
3Ease of manufacture
If an unbalanced valve design is used, then the manufacturing precision and ease of manufacture improve, but the force required to seat the valve deteriorates
Solution Approach 1:
The valve is segmented into two paths with different sealing requirements. The bypass needle valve handles precision low-flow sealing with minimal force requirements, while the main valve handles high-volume flow. This segmentation allows the use of simpler unbalanced design principles in the bypass path without requiring excessive seating force, as the bypass path operates at lower pressures and flows.
Solution Approach 2:
The bypass flow path acts as an intermediary for precision control at low flows, where the needle valve provides accurate flow restriction without requiring high seating forces. This intermediary path handles the precision control function that would otherwise require a complex balanced valve design, allowing the main valve to use simpler unbalanced design principles.
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 provides improved precision and turndown ratios, allowing for accurate low-flow control while maintaining high-volume flow capabilities, and is compact, lightweight, and insensitive to position or vibration, making it suitable for various applications including medical products.
Implementation Method 1
electromagnetic response of the device to a supplied control voltage
Implementation Method 2
linear spring improves the valve actuation
Implementation Method 3
non-linear spring is utilized for the relatively higher magnetic pull of the valve coil for improved control over the greater magnetic force required for higher flow rates
Data Source
AI summary
An electropneumatic proportional flow control device improves electropneumatic control of pneumatically operated valves. Improved turn down ratios in regards to the electromagnetic response of the device to a supplied control voltage is achieved using two variable spring devices, one linear, as part of the pressure regulator valve component, and the other non-linear, as part of the proportional valve component and which are magnetically responsive to different magnetic forces. The use of both the linear and non-linear springs together results in an increased turndown-ratio, especially during initial valve control.