Balanced Plug Assembly for Inlet-Insensitive Pressure Regulation
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Solution Overview
Problem
Pressure regulators with balanced plug assemblies are sensitive to inlet pressure due to pressure differentials, leading to delayed closure and reduced responsiveness to downstream pressure changes, especially when the outlet is flooded with fluid at the same pressure as the inlet.
Innovation Solution
The pressure regulator design includes a stem guide with a balance chamber and flange that divides it into two portions, with balance passages fluidly coupling the fluid passageway and pressure sense chamber, balancing pressure across the stem to reduce the influence of inlet pressure and enhance responsiveness to downstream pressure changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pressure regulator design is used, then the structure is simple, but the regulator becomes sensitive to inlet pressure and responds slowly to downstream pressure changes
Solution Approach 1:
The balance chamber is divided into two separate portions by the flange: a first balance chamber portion exposed to inlet pressure and a second balance chamber portion exposed to downstream pressure. This segmentation allows independent pressure balancing on each side of the stem, eliminating the sensitivity to inlet pressure while maintaining structural feasibility.
Solution Approach 2:
The balance chamber acts as an intermediary mechanism between the inlet pressure and the stem. By introducing this intermediate chamber that can be differentially pressurized, the system mediates the force balance on the stem to achieve responsiveness to downstream pressure changes without being dominated by inlet pressure.
2Reliability
If the outlet is flooded with fluid at the same pressure as the inlet, then the pressure differential is reduced, but the closure response is delayed
Solution Approach 1:
The first balance chamber portion is pre-filled with fluid and maintained at inlet pressure through the balance passage. This preliminary pressurization of the balance chamber portion opposing the stem creates a counterbalancing force that remains effective even when the outlet is flooded, ensuring the regulator can still respond quickly to closure conditions.
3Reliability
If the stem area exposed to inlet pressure is large, then the force balance is affected, but the responsiveness to downstream pressure changes is reduced
Solution Approach 1:
The flange segments the balance chamber to create distinct pressure zones on either side of the stem. This allows the force balance to be controlled by differential pressure across the segmented chambers rather than being dominated by inlet pressure on a large stem surface area, thereby maintaining responsiveness to downstream pressure changes.
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 design reduces the sensitivity to inlet pressure, allowing the pressure regulator to remain responsive and quickly react to changes in downstream pressure, thereby improving the reliability of pressure regulation and over-pressurization protection.
Implementation Method 1
balancing pressure across the stem to reduce the influence of inlet pressure and enhance responsiveness to downstream pressure changes
Data Source
AI summary
Balanced plug assemblies and pressure regulators having balanced plug assemblies are described herein. A pressure regulator disclosed herein includes a device body defining a fluid passageway between an inlet and an outlet. The device body defines a channel between the fluid passageway and a pressure sense chamber. The pressure regulator includes a seat in the fluid passageway, a stem having a flange, and a plug coupled to the stem. The pressure regulator also includes a stem guide disposed in the channel of the device body. The flange of the stem disposed in a balance chamber of the stem guide and divides the balance chamber into a first balance chamber portion and a second balance chamber portion. The stem guide at least partially forms a balance passage that fluidly couples the pressure sense chamber and the second balance chamber portion.