Clamp Ring Isolates Welded Diaphragm Bending Stresses
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Solution Overview
Problem
Welded diaphragm valves face challenges in withstanding bending stresses and moments during flexing and actuation, leading to potential failure under high pressure and cycle rates, especially in applications requiring millions of cycles.
Innovation Solution
A clamp ring is used to apply a compressive load between the diaphragm and the valve body, isolating the weld from bending stresses and moments, utilizing a live load mechanism that maintains compression even under thermal changes and vibrations, and can be integrated with crimped housing designs for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a welded diaphragm is used to provide a body seal, then fluid-tight sealing is improved, but the weld is subjected to bending stresses and moments during valve actuation that can lead to failure
Solution Approach 1:
The clamp ring divides the diaphragm into two functional zones: a clamped region that remains stationary and a welded region that is isolated from bending stresses. This segmentation allows the weld to serve its sealing function without bearing the mechanical loads of diaphragm actuation.
Solution Approach 2:
The clamp ring acts as an intermediary element between the diaphragm and the valve body. It transfers the compressive load to the diaphragm while isolating the weld from bending stresses, thereby protecting the weld from failure while maintaining the fluid-tight seal.
2Ease of operation
If the diaphragm is allowed to flex freely during actuation, then valve operation is improved, but the weld experiences bending stresses that reduce cycle life
Solution Approach 1:
The clamp ring creates a localized clamped region with different mechanical properties from the rest of the diaphragm. The clamped portion remains stationary while the outer portion is free to flex, providing local constraint where needed while maintaining overall diaphragm flexibility for proper valve operation.
Solution Approach 2:
The clamp ring applies a pre-compressive load to the diaphragm before actuation occurs. This preliminary compression ensures that during valve operation, the weld region remains under compression rather than experiencing bending stresses, thereby extending the cycle life of the welded connection.
3Strength
If a clamp ring is added to apply compressive load to isolate the weld, then weld strength and cycle life are improved, but device complexity increases
Solution Approach 1:
The clamp ring serves multiple functions simultaneously: it applies compressive preload to the diaphragm, isolates the weld from bending stresses, and maintains the fluid-tight seal. By consolidating these functions into a single component, the design minimizes the increase in device complexity while achieving multiple protective effects.
Solution Approach 2:
The clamp ring combines the functions of stress isolation, sealing maintenance, and load distribution into a single integrated component. This merging of functions reduces the number of separate parts needed compared to alternative designs that might use multiple elements to achieve the same protective effects.
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 significantly increases the cycle life of welded diaphragm valves, allowing them to operate reliably under high pressures and high cycle rates without diaphragm failure, while maintaining a compact footprint and ensuring a fluid-tight seal.
Implementation Method 1
the compressive load is a spring load or live load produced by an elastic deformation of the member to store potential energy that sustains an applied load on the diaphragm
Data Source
AI summary
A diaphragm sealed flow cavity comprises a first body comprising a support surface, a diaphragm comprising an outer portion that is joined by a weld to the first body, a clamped portion, and an inner portion that is movable along an axis, with the clamped portion of the diaphragm being compressed between the bearing surface and the support surface. The diaphragm sealed flow cavity may include a cylindrical body having a crimped portion for joining the cylindrical body to the first body. The diaphragm sealed flow cavity may also include a member that applies a live load to the clamped portion of the diaphragm. In the exemplary embodiments, the diaphragm sealed flow cavity may be realized as part of a diaphragm flow control valve having a valve body, diaphragm and a housing.