Pinch Valve Closure Geometry for High-Pressure Leak Prevention
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Solution Overview
Problem
Existing pinch valves face issues with effective closure under high pressure without damaging the tubular element, leakage, and contamination due to deformation and trapped fluid, especially in sanitary applications like food and pharmaceuticals.
Innovation Solution
A pinch valve design where the valve member deforms the tubular element into a crescent and U-shape, using a pinch head with convergingly tapered profile and angularly oriented pinch shoulders to ensure complete closure, eliminating gaps and stress concentrations, and preventing fluid trapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the pinch member pinches the tubular element over a short distance, then the valve structure is simpler, but the pinching force must be greater which causes higher stress on the tubular element and potential leakage
Solution Approach 1:
The pinching action is segmented into two distinct zones: a first region where the tubular element is pinched closed by the valve member, and a second region where the tubular element is pinched flat against the valve body. This segmentation distributes the pinching force across different locations and stages, reducing peak stress on any single point of the tubular element while achieving complete closure.
2Reliability
If the tubular element is pinched flat against a flat supporting surface, then the closure appears complete, but small passages remain at the folded ends allowing leakage under high pressure
Solution Approach 1:
The solution transitions from a two-dimensional flat pinching approach to a three-dimensional configuration where the tubular element is first pinched closed in one dimension, then pinched flat against the valve body in a second dimension. This dimensional progression ensures that the folded ends are completely contained and sealed against the valve body surface, eliminating leakage paths that would exist with simple flat pinching.
3Ease of operation
If the valve closing action stretches the tubular element past its elastic limit, then the valve can be actuated, but cavities form between the tubular element and coupling where contaminants can grow
Solution Approach 1:
The valve member is designed with a leading end that begins pinching the tubular element before the main body of the valve member engages. This preliminary pinching action gradually closes the valve and prevents excessive stretching that would occur if the entire valve member engaged simultaneously. The progressive closing action maintains the tubular element within its elastic limit, preventing cavity formation and subsequent contaminant growth.
4Reliability
If greater pinching force is applied to prevent leakage, then closure reliability improves, but the tubular element is damaged and its life is shortened
Solution Approach 1:
The valve member is designed to move progressively through the valve body, creating a dynamic pinching sequence rather than a static single-point compression. The leading end of the valve member engages first and moves forward, progressively pinching the tubular element along its length. This dynamic approach distributes the pinching force over time and space, achieving reliable leakage prevention without concentrating excessive force that would damage the tubular element.
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 design provides reliable, leak-proof closure under high pressures without damaging the tubular element, reducing contamination risks by ensuring fluid is squeezed out and preventing deformation-induced cavities, thus enhancing the valve's longevity and sanitation in applications like food and pharmaceuticals.
Implementation Method 1
a valve member movable to compress or pinch a resilient tubular element extending through a passage of a housing or body of the valve to regulate or prevent fluid flow through the tubular element
Implementation Method 2
a length of a tubular element of a flexible material that carries the fluid
Data Source
AI summary
The pinch valve includes a valve member movable to compress or pinch a resilient tubular element extending through a passage of a housing or body of the valve to varying extents to regulate or prevent fluid flow through the tubular element. The valve member includes a valve head configured to pinch the tubular element through a range of progressively more flow restrictive crescent shapes into a generally U-shape, and while doing so cooperates with side surfaces of the body or housing to bend or fold over lateral end portions of the tubular element that form distal ends of the U-shape. The valve member additionally includes pinch shoulders that follow the pinch head and secondarily pinch or compress the folded over end portions together to complete closure of the tubular element as the U-shape is pinched closed, to prevent leaking, trapping of fluids, and damaging the tubular element under high fluid pressures.