Servo-Controlled Pressure Reducing Valve for Flow-Based Water Mains
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Solution Overview
Problem
Existing pressure regulators in water mains do not effectively manage pressure in response to varying flow demands, leading to increased leaks and inefficiencies, as they are not controlled by flow rates, which are linearly related to required downstream pressure.
Innovation Solution
A fluid pressure reducing valve apparatus with a spring-loaded pressure reducing valve and a controllable servo motor drive, where a controller adjusts the spring position based on flow data from a flow meter to maintain optimal downstream pressure, using a linear or lookup table-based approach to manage pressure in response to changing flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure is increased to maintain minimum pressure at remote points, then pressure reliability is improved, but water loss increases
Solution Approach 1:
The patent applies dynamics by transitioning from a static pressure regulation system to a dynamic one. The servo motor continuously adjusts the spring position based on real-time flow rate measurements from the flow meter, enabling the pressure reducing valve to adapt its output pressure dynamically. This resolves the contradiction by allowing pressure to be increased only when flow demand increases, maintaining reliability while minimizing unnecessary water loss during low-demand periods.
Solution Approach 2:
The patent implements feedback control through the controller that receives flow rate data from the flow meter and uses it to control the servo motor's adjustment of the spring position. This closed-loop feedback system ensures that pressure adjustments are responsive to actual network conditions, increasing pressure only when flow demand increases, thereby maintaining pressure reliability while reducing water loss during low-demand periods.
2Loss of substance
If pressure is reduced to minimize leaks, then water loss is reduced, but downstream pressure reliability deteriorates
Solution Approach 1:
The dynamic adjustment capability allows the system to reduce pressure when flow demand is low (minimizing leaks) while automatically increasing pressure when flow demand rises (maintaining downstream reliability). The servo motor's real-time positioning of the spring based on flow meter feedback enables this dynamic response, resolving the contradiction between leak reduction and pressure reliability.
Solution Approach 2:
The feedback control mechanism ensures that pressure reductions are maintained only as long as flow demand remains low. When the flow meter detects increased demand, the controller activates the servo motor to adjust the spring position, thereby increasing pressure to maintain downstream reliability. This feedback loop prevents downstream pressure failures while minimizing water loss during low-demand periods.
3Device complexity
If fixed pressure regulation is used, then device complexity is reduced, but adaptability to varying flow demands deteriorates
Solution Approach 1:
The feedback control system uses flow rate measurements from the flow meter to dynamically adjust pressure regulation via the servo motor and spring mechanism. This feedback loop provides adaptability to varying flow demands while keeping the regulation mechanism itself relatively simple - the servo motor merely positions the spring based on controller instructions, avoiding complex mechanical regulation mechanisms.
4Ease of operation
If pressure reducing valve is adjusted manually, then ease of operation is maintained, but productivity in responding to flow changes deteriorates
Solution Approach 1:
The system applies self-service by automatically monitoring flow rate through the flow meter and autonomously adjusting the pressure reducing valve via the servo motor and controller. This eliminates the need for manual operation while dramatically improving response speed - the system continuously adapts to flow changes without human intervention, resolving the contradiction between operational simplicity and responsiveness.
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 solution effectively reduces leaks and maintains optimal pressure in water mains by dynamically adjusting the regulation plate to match flow demands, minimizing pressure and thus reducing leak flow rates, even at peak usage periods.
Implementation Method 1
a spring acting to urge the plate towards to the orifice
Implementation Method 2
a controllable motor drive acting between the body and an end of the spring remote from the regulation plate
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A spring loaded regulator (1) has a body (2) containing a chamber (3) with an inlet (4) opening into the chamber via an inlet orifice (5). The inlet connected to a pressurized water main (6). An outlet (7) from the chamber connects to a network (8) of pipes for local distribution of water. The regulator has a flow pressure regulation plate (9) arranged opposite the inlet orifice (5). A diaphragm (10) is fastened to the plate (9) forms a seal with upper and lower parts (11,12) of the body (2). The regulation plate has a guide rod (14) extending down from it into a guide (16) in the inlet orifice (5). A compression spring (21) acts at its lower end (22) on the top of the diaphragm (19). The upper end (23) of the spring abuts a spring drive member (24) at the end of a drive tube (25) of a servo device (26). The drive tube is housed in a fixed tube (27) of the servo device, fast with the upper part (11) of the regulator body (2). Remote from the spring a lead screw (28) is journalled for axial alignment in the drive tube within the fixed tube. A motor (29) and gearbox (30) is arranged to the drive the lead screw. A nut (31) is fast with the remote end of the drive tube (25). Thus the spring drive member can be advanced to further compress the spring or retracted to relieve compression. Downstream from the outlet (7), the pipework (8) of the local distribution network extends. In it adjacent the outlet is a flow meter (32) and a pressure sensor (33). These are electronically connected to a controller (34). Also connected to the controller is a remote pressure sensor (35) at the furthest point (36) of the pipework (8).