Seat Ring Retainer for Control Valves
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Solution Overview
Problem
Conventional methods for retaining seat rings in fluid flow control devices often require high torque, leading to radial distortion and leakage, are costly, and necessitate special tools or machining processes, especially in larger devices where maximizing port size is critical.
Innovation Solution
A seat ring retainer mechanism that uses a threaded or bayonet-type connection to secure the seat ring within the valve body, allowing for minimal torque installation and reduced distortion, eliminating the need for special tools and machining, and facilitating easier repair and replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a threaded engagement method is used to retain the seat ring in the valve body, then the seat ring can be securely retained, but high torque is required which causes radial distortion of the seat ring and compromises the seal
Solution Approach 1:
The retention function is segmented between the retainer component and the seat ring. The retainer provides the threaded engagement with the valve body, while the seat ring is retained by the retainer through a separate mechanical connection (such as a clamp or locking mechanism). This segmentation allows the retainer to bear the high retention forces without transmitting distortion to the seat ring, maintaining both secure retention and seat ring concentricity.
Solution Approach 2:
The retainer acts as an intermediary component between the valve body and the seat ring. It provides the threaded engagement with the valve body for secure retention, while simultaneously providing a protective interface that prevents direct transmission of high torque to the seat ring. This intermediary function allows the seat ring to maintain its concentricity and sealing surface integrity while still achieving secure retention through the retainer mechanism.
2Reliability
If high torque is applied to the seat ring during assembly to achieve a seal, then sealing is improved, but radial distortion increases which degrades shutoff capability
Solution Approach 1:
The sealing function is segmented from the retention function. The retainer provides secure mechanical retention through threaded engagement, while the seat ring achieves sealing through light contact pressure from the retainer rather than high torque application. This segmentation allows the seal to form without subjecting the seat ring to high distortion forces, maintaining both seal quality and alignment precision.
Solution Approach 2:
The retainer serves as an intermediary that transmits minimal retaining force to the seat ring for sealing purposes, rather than transmitting high assembly torque. This intermediary action provides just enough contact pressure to ensure sealing while preventing the radial distortion that would occur with high torque application, thereby preserving seat ring alignment and shutoff capability.
3Reliability
If the seat ring is screwed into the valve body with high torque, then retention security is improved, but special tools and difficult access are required
Solution Approach 1:
The high-torque threaded engagement is extracted from the seat ring and relocated to the retainer component. The retainer is designed with the threaded connection to the valve body, while the seat ring connects to the retainer through a simpler, lower-torque mechanism. This extraction allows standard tools and easier access to be used for assembly, while the retainer maintains secure retention of the seat ring.
Solution Approach 2:
The retainer acts as an intermediary that provides the complex threaded engagement with the valve body, shielding the seat ring from direct high-torque assembly operations. This intermediary arrangement allows the seat ring to be installed using simpler, more accessible methods, while the retainer handles the high-torque retention function that requires robust threaded connection to the valve body.
4Reliability
If bolts in tension are used to attach the seat ring, then secure retention is achieved, but high strength materials are required increasing cost
Solution Approach 1:
The design accepts that the retainer (a relatively simple, lower-cost component) may need to be replaced rather than protecting the expensive seat ring through high-strength bolting. This approach uses standard-strength materials for the retainer that can be economically replaced, while avoiding the need for expensive high-strength materials in the seat ring itself. The retainer serves as a sacrificial or replaceable component that protects the more valuable seat ring from high-stress retention forces.
Solution Approach 2:
The retainer serves as an intermediary component that absorbs the high retention forces through its connection to the valve body, protecting the seat ring from requiring high-strength materials. This intermediary function allows the seat ring to be made from standard materials at lower cost, while the retainer handles the mechanical stress of secure retention through its own structural design and connection to the valve body.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A control valve having a retainer for securing a seat ring within the valve body of the device is disclosed. The seat ring is disposed within a bore in the fluid flow path of the valve body of the control valve, and the retainer is attached to the inner surface of the valve body to retain the seat ring within the bore. The retainer includes threaded openings therethrough for receiving bolts that are tightened down on the seat ring to hold the seat ring against the inner surface of the bore and/or a gasket to form a tight seal and prevent leakage when the control device is in the closed position.