Isolation Valve Assembly for Zero-Pressure Proportional Control
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Solution Overview
Problem
Proportional pressure controllers in pneumatic systems face issues such as increased weight and cost due to solenoid-operated main valves, susceptibility to pressure undershoot or overshoot leading to 'motor-boating', and difficulty in achieving zero pressure at the outlet port, which affects the operation of pressure-controlled devices.
Innovation Solution
The design incorporates poppet valves and an isolation valve assembly with pressure balancing segments and resilient seals to minimize pressure at the outlet port, using pilot valves for actuation and pressure sensing, and an isolation valve assembly to control fluid flow and maintain zero pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solenoid-operated main valves are used to control pressurized fluid flow, then the proportional pressure controller can regulate operating pressure, but the weight and expense of the controller increases and significant electrical current is required
Solution Approach 1:
The patent replaces solenoid-operated main valves with a pilot valve system that uses pneumatic or hydraulic signals to control larger poppet valves. This substitution eliminates the need for heavy solenoid actuators and significant electrical current while maintaining pressure regulation capability through fluid-powered valve actuation.
Solution Approach 2:
The patent employs pilot valves that use pressurized fluid to actuate main poppet valves through pressure differential. The pilot valve receives a control signal that modulates fluid pressure to a chamber behind the poppet, causing the valve to open or close. This pneumatic/hydraulic actuation mechanism replaces electrical solenoids and reduces both weight and electrical power requirements.
2Reliability
If solenoid-operated main valves with mass are used, then pressure regulation is achieved, but pressure undershoot or overshoot occurs leading to motor-boating
Solution Approach 1:
The patent replaces heavy solenoid-operated valves with lightweight poppet valves actuated by pneumatic or hydraulic pressure from a pilot valve. This substitution dramatically reduces valve mass and inertia, enabling faster response to control signals and eliminating the delayed valve action that causes pressure overshoot, undershoot, and motor-boating oscillations.
Solution Approach 2:
The pilot valve system prepares the actuation chamber behind the poppet valve by pre-pressurizing or pre-depressurizing it in response to control signals. This preliminary action ensures that when the valve needs to open or close, the pressure differential is already established, enabling immediate valve response without the lag that causes pressure instability and motor-boating.
3Reliability
If a standard proportional pressure controller configuration is used, then pressure regulation is provided, but zero pressure at the outlet port cannot be achieved
Solution Approach 1:
The patent extracts residual pressurized fluid from the outlet port and downstream passages by providing a dedicated exhaust path that vents to the exhaust port. This extraction of trapped pressurized fluid enables the outlet port to achieve true zero pressure conditions, which is essential for certain pressure-controlled device operations, while the main pressure regulation function remains intact through the poppet valve and pilot valve system.
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 the likelihood of pressure at the outlet port when zero pressure is desired, mitigates motor-boating, and maintains accurate pressure control with reduced energy consumption and cost, enhancing the performance and reliability of pressure-controlled devices.
Implementation Method 1
a resilient seal arranged to be compressed by movement of the isolation valve member to seal against the outlet port
Implementation Method 2
a first poppet valve in the body having a first seat and configured to open or close fluid flow between the inlet port and the outlet port in response to a pressure differential across the first poppet valve
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A proportional pressure controller includes a body having inlet, outlet, and exhaust ports. A fill valve communicates with pressurized fluid in the inlet port. A dump valve communicates with pressurized fluid from the fill valve. An inlet poppet valve opens by pressurized fluid through the fill valve. An exhaust poppet valve when closed isolates pressurized fluid from the exhaust port. An outlet flow passage communicates with pressurized fluid when the inlet poppet valve is open, and communicates with the outlet port and an exhaust/outlet common passage. An isolation valve assembly selectively isolates fluid flow to and from the inlet port or the exhaust port to achieve a zero pressure condition.