Flow Rate Controller for High Pressure Drop Stability
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Solution Overview
Problem
Conventional flow rate controllers are inadequate in maintaining constant flow rates during large pressure fluctuations and are prone to cavitation, leading to unstable operation and noise issues due to inadequate pressure handling and balance.
Innovation Solution
A pressure-independent flow rate controller design that includes a piston with balanced seal members and a throttling assembly, which maintains a constant flow rate by balancing opposing forces across the valve, reducing cavitation, and mitigating noise through a restriction assembly that adjusts to maintain a consistent pressure differential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pressure compensated flow control valves are used, then flow rate control is provided, but the valves are susceptible to inadequate control or inadvertent closure upon large pressure differential or pressure spike
Solution Approach 1:
The valve is segmented into multiple functional sections: a pressure balanced section with flow entering under the seat first, followed by a pressure compensated section with flow over the throttle cone. This segmentation allows each section to handle specific pressure conditions independently, enabling the valve to maintain control stability while adapting to large pressure differentials and spikes.
Solution Approach 2:
The patent inverts the conventional flow sequence by having flow enter under the seat first rather than over the throttle cone first. This inversion creates a pressure balanced condition that stabilizes the valve against large pressure differentials and spikes, preventing inadvertent closure while maintaining flow control capability.
2Reliability
If pressure balanced rate control valves with large balanced area are used, then pressure balance is improved, but the valves go into cyclic opening and closing sequence with excessive pressure drops
Solution Approach 1:
The patent applies different local qualities to different sections of the valve: the pressure balanced section uses a large area ratio for pressure balance, while the pressure compensated section uses a smaller, optimized throttle area. This local differentiation allows the valve to achieve pressure balance without the excessive pressure drops that cause cyclic opening and closing, maintaining operational stability.
Solution Approach 2:
The patent introduces dynamic elements including a resilient member (spring) that dynamically adjusts to pressure changes, and a pilot orifice that dynamically balances pressure across the resilient member. This dynamic adjustment prevents the cyclic opening and closing behavior by continuously adapting to pressure conditions while maintaining stable operation.
3Productivity
If conventional valves operate with large pressure drops, then flow rate control is maintained, but cavitation occurs causing erosion, noise, and vibration
Solution Approach 1:
The patent performs preliminary pressure reduction in staged steps: first under the seat, then through the pressure balanced section, and finally through the pressure compensated section. This preliminary, staged pressure reduction prevents sudden pressure drops that cause cavitation, allowing the valve to maintain flow rate delivery while avoiding erosion, noise, and vibration associated with cavitation.
4Ease of operation
If conventional spring compensated regulating devices are used, then flow rate control is provided, but the devices resonate with distribution lines causing shaking and vibration
Solution Approach 1:
The patent introduces a pilot orifice as an intermediary element that mediates pressure transmission to the resilient member. This intermediary provides pressure damping and isolates the main valve mechanism from high-frequency pressure fluctuations, preventing resonance with distribution lines while maintaining ease of flow rate regulation.
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 effectively extends the allowable pressure drop across the valve without cavitation, reducing noise and vibration, ensuring stable flow rate delivery even with significant pressure changes, thus eliminating the need for noise suppression measures.
Implementation Method 1
The size of the piston and the effective areas acted upon by the fluid at the intermediate and outlet pressures (P2 and P3) are such that the piston spring and associated dynamic seals balance the opposing forces in the interior chamber
Implementation Method 2
The throttling member is movable relative to the throttling seat to regulate fluid flow through the throttling assembly
Implementation Method 3
a restriction assembly that adjusts to maintain a consistent pressure differential
Implementation Method 4
This device must be able to withstand high pressure drops without experiencing cavitation
Data Source
AI summary
A flow rate controller is disclosed that maintains constant flow rate with changes in pressure drop across the valve by maintaining a constant pressure drop across a restrictor with the aid of a spring balanced piston that mates a cone to a seat to dissipate the majority of pressure drop across the valve.