Cascade Trim Control Valve for Dirty Fluid Handling
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Solution Overview
Problem
Conventional fluid control valves face issues with cavitation and ineffectiveness when dealing with dirty fluids, as debris can clog passageways, altering fluid control properties and causing damage.
Innovation Solution
A cascade trim control valve with intricate and complex flow passages in both the valve stem and cage, featuring multiple fluid passageway columns that can be aligned to vary fluid control properties, and a discharge chamber to collect debris, preventing clogging and enhancing rangeability and controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional disk-stack type valves are used, then the valve structure is simple, but the valve is ineffective with dirty fluids as debris clogs passageways
Solution Approach 1:
The cage is divided into multiple stacked disks that form separate tortuous flow passages, allowing debris to be trapped between disks while maintaining fluid control functionality. This segmentation prevents clogging by isolating debris particles in specific zones rather than allowing them to block the entire flow path.
Solution Approach 2:
The valve stem is nested within the cage structure, with the stem moving reciprocally through the stacked disks. This nested configuration allows the stem to control flow through the tortuous passages formed by the disks while the outer cage structure provides debris containment zones.
2Reliability
If conventional control valves are used, then the valve structure is simple, but cavitation occurs causing damage to valve structure
Solution Approach 1:
The cage disks are configured to create tortuous (curved) flow passages rather than straight paths. This curvature causes the fluid to follow a winding path through the valve, which dissipates energy and reduces the intensity of cavitation bubbles, thereby protecting the valve structure from cavitation damage.
3Ease of manufacture
If disk-stack type valves are used, then manufacturing is simple, but the valves tend to be ineffective when used with dirty fluids as debris may clog the passageways within the cage
Solution Approach 1:
The cage is constructed from multiple stacked disks with simple individual geometries that are easy to manufacture, yet when assembled they create complex tortuous passages. The segmentation allows debris to be trapped in the spaces between disks while maintaining manufacturing simplicity for each individual component.
4Adaptability or versatility
If intricate and complex flow passages are formed in valve stem and cage, then rangeability and controllability are improved, but device complexity increases
Solution Approach 1:
The valve stem is made movable within the cage, allowing dynamic adjustment of the flow passages. As the stem moves reciprocally, it selectively opens and closes different flow paths through the tortuous passages, enabling continuous variation of flow control properties and improving rangeability without requiring a completely complex fixed structure.
Data Source
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AI summary
A cascade type trim for integration into control valve and having a valve stem and a valve cage which cooperate with each other to define a plurality of fluid passageway columns, each of which extend between a valve inlet and a valve outlet. Each fluid passageway column is collectively defined by a plurality of stem passageways and a plurality of cage passageways. The stem and cage passageways are brought in and out of alignment as a result of axial movement of the stem relative to the cage. In a first position, a first fluid passageway is open, while a second fluid passageway remains closed. In a second position, both the first and second fluid passageways are open, and yet in a third position, the first fluid passageway is closed and the second fluid passageway is open.