Digital Pressure Valve Assembly for Overshoot-Free Outlet Control
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Solution Overview
Problem
Proportional pressure controllers face issues with weight, cost, electrical current consumption, system pressure undershoot or overshoot, and difficulty in achieving zero pressure at the outlet, leading to increased wear and contamination risks.
Innovation Solution
A valve assembly with fill and dump valves controlled by a digital controller that dynamically adjusts fluid flow based on desired and actual pressure signals, using high-flow and low-flow valves to precisely manage pressure and prevent overshoot or undershoot, and includes a secondary exhaust to isolate contaminated fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solenoid actuators are used to reposition main valves, then pressure control function is achieved, but weight and expense increase
Solution Approach 1:
The patent replaces solenoid actuators with a pneumatic spring mechanism. The pneumatic spring uses compressed gas stored in a reservoir to provide the restoring force that repositions the main valve, eliminating the need for electrical solenoids and their associated heavy components.
Solution Approach 2:
The invention uses pneumatic principles throughout: compressed gas stored in a reservoir provides the restoring force for valve repositioning, and a pilot valve controls gas flow to actuate the main valve. This pneumatic system replaces the electrical-mechanical solenoid actuation system.
2Reliability
If solenoid actuators are used to reposition main valves, then pressure control function is achieved, but electrical current consumption increases
Solution Approach 1:
The patent replaces solenoid actuators with a pneumatic spring mechanism. The pneumatic spring uses compressed gas stored in a reservoir to provide the restoring force that repositions the main valve, eliminating the need for electrical solenoids and their associated heavy components.
Solution Approach 2:
The invention uses pneumatic principles throughout: compressed gas stored in a reservoir provides the restoring force for valve repositioning, and a pilot valve controls gas flow to actuate the main valve. This pneumatic system replaces the electrical-mechanical solenoid actuation system.
3Reliability
If main valves with significant mass are used, then pressure control capability is achieved, but system pressure undershoot or overshoot occurs
Solution Approach 1:
The patent segments the valve control into two parts: a main valve for bulk flow control and a pilot valve for precise pressure regulation. The pilot valve, being smaller and lighter, can respond quickly to pressure changes and provide precise control, while the main valve handles the majority of the flow control task.
Solution Approach 2:
The pilot valve acts as an intermediary between the pressure sensor and the main valve. It receives feedback from the pressure sensor and controls the flow of compressed gas to the main valve, providing indirect but precise control that prevents overshoot and undershoot.
4Manufacturing precision
If rapid opening and closing sequence is used to control pressure, then desired operating pressure is pursued, but wear and operating costs increase
Solution Approach 1:
The system uses a pressure sensor to continuously monitor the actual pressure and provide feedback to the controller. The controller compares this with the desired pressure and adjusts the pilot valve accordingly, creating a closed-loop control system that prevents extreme hunting behavior and reduces valve wear.
Solution Approach 2:
The pneumatic spring provides a dynamic, responsive restoring force that allows the valve to adjust smoothly to pressure changes without the rigid on/off switching characteristic of solenoid systems. This dynamic response reduces hunting and wear.
5Device complexity
If single exhaust port is used, then simple structure is maintained, but zero pressure condition cannot be achieved at outlet
Solution Approach 1:
The exhaust function is segmented into two separate ports: a primary exhaust for normal operation and a secondary exhaust for achieving zero pressure conditions. This segmentation allows the system to achieve complete pressure relief when needed while maintaining simple operation during normal conditions.
Solution Approach 2:
The secondary exhaust port is prepared in advance specifically for achieving zero pressure conditions. When complete pressure relief is required, the system can immediately utilize this pre-configured pathway without requiring complex additional components or modifications.
6Device complexity
If outlet port is directly connected to pressure controlled device, then simple fluid path is maintained, but contaminated fluid backflows into controller
Solution Approach 1:
The pressure sensor is extracted from the contaminated outlet environment and placed in a protected location. A separate sensing port provides a clean pathway for pressure measurement, isolating the sensor from contaminated fluid that may backflow through the outlet port.
Solution Approach 2:
A sensing port acts as an intermediary between the outlet and the pressure sensor. This intermediary pathway allows the sensor to accurately measure outlet pressure while being physically isolated from the contaminated fluid, preventing contamination of the controller.
Data Source
AI summary
A valve assembly having a plurality of fill valves that permit a fluid to flow from a fluid inlet into an interior flow path to increase a pressure of the fluid output from a fluid outlet, and a plurality of dump valves that permit the fluid to flow from the interior flow path to an exhaust to reduce the pressure of the fluid output from the fluid outlet. The valve assembly includes a controller that is configured for receipt of a command signal including a desired pressure of the fluid to be output from the fluid outlet, and is configured for receipt of a signal from a pressure sensor that is indicative of an actual pressure of the fluid output from the fluid outlet, wherein based on a comparison of the command signal with the signal indicative of the actual pressure, the controller is configured to selectively open and close each of the fill valves and each of the dump valves until the actual pressure is equal to the desired pressure.