Membrane Valve Switching Element Curvature and Coating
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Solution Overview
Problem
Existing membrane valves face challenges in achieving precise control and quick, safe opening/closing of valve passages, especially when handling abrasive media, due to wear and limited controllability.
Innovation Solution
A membrane valve design with a movably mounted switching element that presses a silicone membrane against radially arranged sealing surfaces, featuring a 360° annular membrane, convexly curved sealing regions, and a sliding surface with a PTFE coating, which reduces friction and wear, and includes a locking device for defined switching positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a membrane valve uses a switching element to press the membrane against sealing surfaces, then the valve passage can be closed reliably, but wear occurs on the membrane and sealing surfaces due to friction
Solution Approach 1:
The switching element is designed with a convexly curved sealing region that matches the concavely curved sealing surface in the valve passage. This curved geometry ensures point or line contact during closure, minimizing the sliding distance and contact area between the membrane and sealing surfaces, thereby reducing wear while maintaining reliable sealing.
Solution Approach 2:
A sliding surface with PTFE coating is introduced between the switching element and the membrane. This intermediary layer reduces friction and wear during the switching operation, allowing the membrane to slide smoothly against the coated surface rather than directly against the sealing surface, thus extending the service life of both the membrane and sealing surfaces.
2Measurement precision
If the recess of the valve passage is elongated in the circumferential direction, then fine controllability is achieved, but the opening and closing speed decreases
Solution Approach 1:
The valve passage recess is designed to be elongated transversely to the circumferential direction of the switching element, creating a dynamic opening/closing action. When the switching element moves in the circumferential direction, it quickly engages the membrane against the sealing surface due to the transverse elongation, achieving fast closure while maintaining precise controllability through the limited angular travel required.
3Measurement precision
If the switching element is moved in the circumferential direction to control the valve, then fine controllability is achieved, but friction and wear increase
Solution Approach 1:
The convexly curved sealing region of the switching element working with the concavely curved sealing surface creates a localized contact zone that minimizes sliding distance. The curved geometry guides the membrane into proper alignment during circumferential movement, reducing lateral friction and wear while maintaining precise controllability through the curved path.
Solution Approach 2:
The PTFE-coated sliding surface acts as an intermediary between the switching element and membrane, reducing the coefficient of friction during circumferential movement. This allows the switching element to be moved precisely in the circumferential direction with minimal friction and wear on both the switching element and membrane surfaces.
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 achieves fine controllability, quick and secure opening/closing of valve passages, minimizes wear, and ensures reliable sealing even with abrasive media, while preventing unintentional closure and reducing operational friction.
Implementation Method 1
featuring a 360° annular membrane, convexly curved sealing regions, and a sliding surface with a PTFE coating, which reduces friction and wear
Implementation Method 2
a movably mounted switching element closes at least one of the valve passages in at least one switching position, in that the switching element presses the at least one membrane against at least one sealing surface
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The diaphragm valve has a housing (12a) enclosing a diaphragm. Two valve passages (14a,16a) are provided in housing. A movable switch element (18a) is mounted for opening and closing the valve passages. A specific valve passage is closed by pressing the diaphragm against sealing surface of specific valve passage, when switch element is in one position.