Membrane Valve Pin Shaft Design for Sealing and Flow
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Solution Overview
Problem
Existing membrane valves for inhalation devices face challenges in achieving a high sealing effect against liquids while maintaining low resistance to air flow, with prior solutions either increasing stiffness or allowing liquid ingress due to capillary effects.
Innovation Solution
The pin's shaft is enlarged near its head to create a dome shape in the membrane, with the enlarged diameter pressing the membrane against the frame at its outer edge, ensuring high contact pressure and sealing without stiffening the membrane, and a stop ensures correct insertion depth to maintain membrane flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the membrane edge is folded over to increase contact pressure for better liquid sealing, then the sealing effect against liquids is improved, but the membrane becomes stiffer and requires elevated pressure to move during inhalation
Solution Approach 1:
The pin shaft is designed with varying diameter: a larger diameter section near the head creates localized doming at the membrane center, while a smaller diameter section at the free end maintains membrane flexibility at the edges. This local differentiation allows the membrane to have both sealing contact at the periphery and flexibility for inhalation movement.
Solution Approach 2:
The pin shaft transitions from a simple cylindrical form to a multi-dimensional structure with varying cross-sections. The enlarged shaft diameter near the head creates a three-dimensional doming effect in the membrane, while the reduced diameter at the free end preserves two-dimensional flexibility, solving the contradiction between sealing and flexibility.
2Ease of operation
If a ring-shaped membrane is used to reduce resistance to respiratory air, then the air flow resistance is reduced, but capillary slits are formed that allow liquid ingress through capillary effects
Solution Approach 1:
The membrane is designed with differentiated zones: the outer edge region provides sealing contact with the frame to prevent liquid ingress, while the inner portion with the dome shape maintains flexibility and low resistance to air flow. This local quality differentiation resolves the contradiction between flow resistance and liquid sealing.
3Strength
If the pin shaft has a uniformly large diameter to secure the membrane, then the membrane is firmly retained, but the membrane flexibility is reduced and air flow resistance increases
Solution Approach 1:
The pin shaft features localized diameter variation: a larger diameter section near the head provides strong retention and creates beneficial doming, while a smaller diameter section at the free end preserves membrane flexibility. This local differentiation simultaneously achieves strong retention and maintains ease of operation.
Solution Approach 2:
The pin shaft is segmented into functional zones with different diameters: the enlarged section near the head handles retention and sealing, while the reduced section at the free end handles flexibility. This segmentation allows each part to optimize its specific function without compromising the other.
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 a high sealing effect against liquids while maintaining low air resistance and flexibility, allowing for uniform distribution of pretension force across the membrane, effectively preventing liquid ingress and optimizing air flow.
Implementation Method 1
In the outer layer of the membrane, which is more distant from the frame, the membrane is pressed apart by the increased diameter of the shaft. By this means, radially acting forces emanating from the centre of the outer surface of the membrane occur, which press the permanently flexible material of the membrane outward.
Implementation Method 2
When the organism inhales again, the direction of the air stream reverses, so that the pressure on the membrane is eliminated and, by virtue of the elasticity of its material, it returns to the rest state in which it blocks the inflow of gases and liquids by lying on the frame.
Data Source
AI summary
The invention relates to a membrane valve, in particular for inhalation devices, comprising a planar membrane made of permanently flexible material, a frame, which has an air opening that is somewhat smaller than the membrane, at least one web, which connects the frame to a retainer that is arranged approximately at the center of the air opening, and a pin, the shaft of which extends through a fastening opening approximately at the center of the membrane and is located in a retaining opening in the retainer, wherein the membrane lies on the frame in the rest state and wherein the pin is spread to form a head, the distance of which to the membrane is small in comparison to the thickness of the membrane or which head lies on the membrane, and the diameter of the shaft near the head is greater than the diameter of the fastening opening,; and the diameter of the shaft at the free end of the shaft is approximately equal to the diameter of the fastening opening.