Constant-Flow Valve with Adjustable Restrictor
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Solution Overview
Problem
Existing flow control valves in the oil and gas industry face challenges in maintaining a constant flow rate despite significant pressure fluctuations, often leading to clogging and limited flow range due to the use of fixed orifices, which requires frequent replacements and increases operational costs, especially in remote locations.
Innovation Solution
A constant-flow valve assembly with an adjustable restrictor assembly and piston mechanism that maintains a substantially constant fluid flow independent of pressure differentials, allowing for a wide range of flow rate set points and reducing the need for frequent orifice replacements by adjusting the flow rate through a movable restrictor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed orifice is used to control flow rate, then the valve structure is simple and robust, but the flow rate range is limited and requires frequent orifice replacements when flow needs to be adjusted
Solution Approach 1:
The patent applies dynamics by replacing the fixed orifice with a movable needle that can adjust the flow area dynamically. The needle position is controlled by a piston mechanism that responds to pressure differentials, allowing the valve to adapt to varying flow requirements without requiring physical replacement of orifices. This dynamic adjustment capability directly resolves the contradiction between adaptability and device complexity.
Solution Approach 2:
The valve is segmented into distinct functional components: a fixed orifice plate with multiple holes, a movable needle for flow restriction, and a piston mechanism for control. This segmentation allows the fixed orifice to provide robust debris passage while the movable needle provides adjustable flow control, combining the advantages of both fixed and variable geometry designs without the drawbacks of either extreme.
2Adaptability or versatility
If the pressure drop across a fixed orifice is varied to change flow rate, then the method is robust and can pass debris, but the flow rate set point range is limited
Solution Approach 1:
The movable needle dynamically adjusts the flow area to maintain optimal flow conditions across a wide range of set points. By varying the needle position rather than relying solely on pressure drop changes, the system achieves broader flow rate adjustment while maintaining reliable debris passage capability through the fixed orifice holes.
Solution Approach 2:
The design merges the debris-passing capability of a fixed orifice with the flow-adjustment capability of a variable restrictor. The fixed orifice plate with multiple holes handles debris passage robustly, while the movable needle superimposed on it provides precise flow rate control, combining the strengths of both approaches.
3Productivity
If a valve is designed for high flow rates, then the orifice can be large, but the turn down ratio is limited requiring personnel access for orifice replacement
Solution Approach 1:
The valve incorporates a self-adjusting mechanism where the piston automatically positions the needle to maintain the desired flow rate based on pressure differential changes. This eliminates the need for manual orifice replacement and allows flow rate adjustment without personnel access to remote valve locations, making the system self-regulating and easy to operate.
Solution Approach 2:
The dynamic needle positioning mechanism allows continuous flow rate adjustment from high to low settings without requiring physical intervention. The piston-controlled needle movement provides automated adaptability that maintains ease of operation across the entire flow range, resolving the accessibility problem associated with fixed orifice replacement.
4Measurement precision
If a mating needle and trim are used to restrict flow to less than 0.001 inches, then precise flow control is achieved, but the passages are prone to clogging and filming
Solution Approach 1:
The design combines a fixed orifice with multiple relatively large holes (providing robust debris passage) with a movable needle that creates the precise flow restriction. This merging allows the system to achieve precise flow control (0.001 inches or less) through the needle while the fixed orifice holes remain large enough to pass debris, eliminating the clogging problem associated with small precision passages.
Solution Approach 2:
The flow control function is segmented between the fixed orifice plate (handling debris passage with multiple holes) and the movable needle (handling precise flow restriction). This segmentation allows each component to be optimized for its specific function: the orifice holes can be larger and more numerous for debris passage, while the needle provides the precise restriction needed for flow control without being susceptible to clogging.
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 ensures a consistent flow rate across varying pressure conditions, reduces clogging and filming tendencies, and minimizes the need for frequent maintenance or replacements, thereby lowering operational costs and improving efficiency.
Implementation Method 1
A piston is slideably disposed in the chamber... The adjustable valve member is configured to provide a substantially constant fluid flow to the third passageway substantially independent of the pressure differentials between the second and third fluid pressures
Data Source
AI summary
In one embodiment, a constant-flow valve assembly is provided that comprises a first fluid passageway carrying fluid at a first fluid pressure, a piston chamber, and a second fluid passageway connected to the chamber and carrying fluid at a second fluid pressure. A third fluid passageway is configured to carry fluid at a third fluid pressure. An adjustable valve member is provided between the chamber and the third passageway to provide constant fluid flow to the third passageway. An adjustable restrictor assembly is positioned between the first and second fluid passageways. An inlet portion of the restrictor assembly receives fluid at the first fluid pressure and directs the fluid to a restrictor. An outlet portion receives fluid from the restrictor and directs the fluid to the second fluid passageway at the second fluid pressure. The restrictor is movable to adjust the position of entry and exit portions relative to the inlet and outlet portions to adjust a fluid flow rate through fluid pathway to the second fluid passageway, thereby adjusting the flow rate through the valve assembly.