Pilot Valve Assembly for Automatic Flow Control
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Solution Overview
Problem
Existing automatic pressure-reducing valves in water distribution systems face challenges in maintaining optimal downstream pressure, particularly during peak demand conditions, leading to potential equipment damage due to excessive opening of the main valve and increased installation and servicing costs for electronically controlled valves.
Innovation Solution
An automatic flow control system with a pilot valve assembly that utilizes a differential pilot valve apparatus responsive to pressure differentials to control the main valve, incorporating a restriction mechanism to manage flow and pressure, allowing for multiple pressure set points without the need for external power sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid push rod transfers diaphragm movement to a controlling valve member, then the valve structure is simple and robust, but the actuator diaphragm movement is severely limited reducing valve sensitivity
Solution Approach 1:
The push rod is segmented into multiple sections with varying diameters rather than being a uniform rigid rod. This segmentation allows different sections to flex at different rates, enabling the push rod to transmit motion while accommodating larger diaphragm movements without compromising structural integrity.
Solution Approach 2:
The push rod transitions from a static rigid structure to a dynamic flexible structure that can adapt its stiffness along its length. The varying diameter creates zones of different flexibility, allowing the rod to bend and extend its range of motion while maintaining sufficient structural strength.
2Productivity
If the main valve is opened excessively during high flow, then high flow demand is met, but downstream pressure becomes excessively high causing damage to equipment
Solution Approach 1:
The system incorporates downstream pressure sensing that provides feedback to the diaphragm actuator. When downstream pressure reaches a predetermined threshold, the feedback mechanism reduces the actuator's opening force, preventing the valve from opening excessively even during high flow demand conditions.
Solution Approach 2:
The valve opening characteristic is dynamically adjusted based on downstream pressure conditions. The relationship between actuator force and valve opening changes as a function of downstream pressure, allowing the valve to maintain optimal opening positions that prevent excessive pressure while accommodating varying flow demands.
3Measurement precision
If electronically controlled valves are used to vary set-point, then downstream pressure can be precisely controlled, but installation and servicing costs increase due to power source requirements
Solution Approach 1:
The valve system uses the process fluid itself (water pressure) to power the actuator mechanism. The diaphragm is actuated by downstream pressure feedback without requiring external electrical power sources, making the system self-sufficient and eliminating the complexity of electrical installations.
Solution Approach 2:
The control mechanism transitions from electrical actuation to hydraulic actuation using the process fluid. Downstream water pressure is directly applied to the diaphragm to control valve opening, replacing electronic control systems with a simpler hydraulic feedback mechanism that uses the existing fluid pressure.
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 system effectively regulates downstream pressure based on flow demand, reducing the risk of equipment damage and lowering installation and servicing costs by using hydraulic control to adjust valve operation, ensuring consistent and efficient water distribution.
Implementation Method 1
The differential pilot valve apparatus is responsive to the pressure differential to move the differential valve member between an open position in which water flows from the differential valve inlet to the differential valve outlet
Implementation Method 2
The first pilot valve apparatus is responsive to a first pressure to close the first pilot valve member to reduce flow of water therethrough
Implementation Method 3
The second pilot valve apparatus is responsive to a second pressure to close the second pilot valve member to reduce flow of water therethrough
Implementation Method 4
A restriction mechanism is disposed between the inlet and the outlet for creating a pressure differential
Data Source
AI summary
A pilot valve assembly for use with a main valve apparatus coupled to a water pipe, includes a differential pilot valve, and first and second pilot valves. An inlet of the differential pilot valve is coupled to a junction and an outlet is coupled to the first pilot valve. The differential pilot valve is responsive to a pressure differential to open and close the differential pilot valve to control water flow therethrough to the first pilot. The first pilot valve is responsive to a first pressure to close the first pilot valve to reduce water flow therethrough. The second pilot valve is coupled to the junction to facilitate water flow through the second pilot valve when the differential valve member is open. The second pilot valve is responsive to a second pressure to close the second pilot valve to reduce water flow therethrough.