Cold-Worked Diaphragm for Valve Hysteresis Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Proportional control valves in high-purity fluid delivery systems face performance limitations due to hysteresis issues in actuators and diaphragms, particularly in handling hazardous fluids where traditional packing-type seals can cause contamination and safety concerns.
Innovation Solution
A metallic diaphragm is cold worked to create a ring-shaped, conically deformed region, inducing compressive forces and eliminating hysteresis by providing a consistent spring force, which is achieved through axial loading and strain hardening, using a corrosion-resistant alloy like type 316 stainless steel or Hastelloy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional packing-type seals are used in proportional control valves, then sealing function is provided, but hysteresis occurs and performance is limited
Solution Approach 1:
The patent removes the traditional packing-type seal from the valve system and replaces it with a diaphragm sealing mechanism. This extraction of the problematic packing seal eliminates the source of hysteresis while maintaining the sealing function through the diaphragm's flexible barrier that separates the process fluid from the actuator chamber.
Solution Approach 2:
The patent employs a diaphragm made of flexible material (elastic polymer or metal) that acts as both a sealing barrier and a mechanical element for force transmission. The diaphragm's flexibility allows it to maintain seal integrity while responding to pressure changes without the friction and hysteresis associated with packing seals, enabling precise proportional control.
2Ease of manufacture
If a flat diaphragm is used, then manufacturing is simpler, but hysteresis occurs in proportional control
Solution Approach 1:
The patent pre-forms the diaphragm with a conical shape during manufacturing, creating a permanent geometric modification that establishes the desired mechanical behavior before the diaphragm is installed. This preliminary shaping ensures that when the diaphragm is in use, it operates in a predetermined stress state that eliminates hysteresis and enables accurate proportional control without requiring complex real-time adjustments.
3Loss of substance
If the diaphragm is made flat and thin, then material usage is reduced, but spring force and hysteresis control are compromised
Solution Approach 1:
The patent introduces a conical curvature to the diaphragm, transforming it from a flat plane to a three-dimensional shaped surface. This curvature modification changes the stress distribution and mechanical response of the diaphragm, enabling it to provide consistent spring force and eliminate hysteresis while still using minimal material. The conical shape creates a mechanical advantage that enhances the diaphragm's elastic recovery characteristics.
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 enhances the performance of proportional valves by reducing hysteresis and ensuring leak-tight sealing, improving the handling of hazardous fluids while maintaining high purity and safety standards.
Implementation Method 1
a plastically deformed concentric strain hardened region having a concave shape
Implementation Method 2
inducing compressive forces and eliminating hysteresis by providing a consistent spring force
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A valve diaphragm processed by cold working a small concentric region of one surface has a permanent axisymmetric deformation. The deformed diaphragm can be used in a manner which causes continual elastic compression loading of the diaphragm material. The loading of the deformed diaphragm provides a valve restoring spring force and simultaneously defeats diaphragm tendency toward exhibiting hysteresis. The restoring force provided by the diaphragm can also lessen actuator hysteresis.