Nested Flow-Passage Valve Trim for Cavitation and Noise Control
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Solution Overview
Problem
Control valves experience cavitation and resultant noise and vibration due to pressure drops, which existing valve trims fail to adequately address while maintaining flow volume, especially in ball and butterfly valves where pressure drops occur in a single stage.
Innovation Solution
A valve trim design featuring parallel flow passages with nested throats and expansion chambers, where each throat is nested between adjacent expansion chambers, allowing for maximized flow area and multi-stage cavitation control and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple cylindrical tubes with homogenous cross sections are used as valve trim, then the structure is simple and easy to manufacture, but the flow passages do not provide pressure drop chambers to assist in cavitation and noise reduction
Solution Approach 1:
The valve trim is segmented into multiple flow passages, each containing a throat section and an expansion chamber section. This segmentation allows the creation of distinct pressure drop zones (throats) and expansion zones (chambers) within each passage, enabling cavitation control while maintaining manufacturability through modular design.
Solution Approach 2:
The invention transitions from homogenous cross-sectional tubes to passages with varying cross-sections along the flow direction. Each passage features a throat with a smaller cross-sectional area followed by an expansion chamber with a larger cross-sectional area, creating multi-stage pressure drops that reduce cavitation and noise while maintaining structural feasibility.
2Object-affected harmful factors
If identical flow passages with expansion chambers are formed adjacent each other, then cavitation and noise are reduced, but the flow passages must be spaced apart which limits the flow volume through the valve trim
Solution Approach 1:
The flow passages are arranged in a nested or interlocked configuration where expansion chambers of adjacent passages are positioned to be directly adjacent to each other. This nesting arrangement eliminates the need for spacing between passages, allowing the passages to be tightly packed within the valve trim body, thereby maximizing the total flow volume while maintaining multi-stage cavitation control.
Solution Approach 2:
Adjacent expansion chambers are merged or positioned directly adjacent to each other, creating a continuous boundary between passages. This merging eliminates wasted space between passages and allows for tighter packing of multiple flow passages within the same valve trim envelope, increasing overall flow capacity while preserving noise reduction functionality.
3Device complexity
If pressure drop occurs in only one stage through the valve, then the valve structure is simple, but cavitation and resultant noise and vibration are created
Solution Approach 1:
The single pressure drop is segmented into multiple stages within each flow passage. The throat section creates a first pressure drop, and the subsequent expansion chamber creates a second pressure drop. This segmentation of the pressure drop into multiple stages reduces cavitation and noise while maintaining relatively simple valve geometry and structure.
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 design effectively reduces cavitation and noise while maximizing flow volume through the valve trim by staggering pressure drop stages along the flow axis, enhancing the flow capacity and noise attenuation.
Implementation Method 1
cavitation and resultant noise and vibration from cavitation are created when a liquid flowing through the control valve undergoes a high pressure drop. Cavitation occurs when fluid vaporizes and then returns to a liquid state
Implementation Method 2
The fluid can reach its vapor point due to decrease in pressure and increase in velocity at the restriction
Data Source
AI summary
A valve trim includes a body having a plurality of parallel flow passages extending from a first end of the body to a second end of the body, opposite the first end. Each flow passage includes a throat and an expansion chamber and each throat is nested between the expansion chambers of directly adjacent flow passages.