Butterfly Valve Disc Geometry for More Progressive Opening
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Solution Overview
Problem
Conventional butterfly valves exhibit low sensitivity and progressivity in opening due to a non-linear trend of fluid passage slots as the rotation angle varies, resulting in smaller apertures at equal rotation angles.
Innovation Solution
The closure member is designed with portions offset in opposite directions relative to the axis of rotation, featuring a disc shape divided into two halves joined by a central wall oriented at 45° to the flow direction, creating a stepped profile that increases fluid passage slots in the closed position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional circular disc closure member is used, then the valve structure is simple, but the fluid passage slots show low sensitivity and low progressivity in opening action
Solution Approach 1:
The closure member is segmented into two half-discs joined by a central wall, creating offset portions that improve the fluid passage characteristics while maintaining operational simplicity
Solution Approach 2:
The closure member features asymmetric offset portions relative to the rotation axis, with forward and backward walls created by the offset half-discs, which enhances the linearity and progressivity of the opening action
2Productivity
If a conventional circular disc closure member is used, then the manufacturing is simple, but the apertures are smaller at equal rotation angles
Solution Approach 1:
Dividing the disc into two offset half-discs creates larger fluid passage slots at equal rotation angles, improving productivity despite increased manufacturing complexity
Solution Approach 2:
The offset portions extend the closure member in the axial dimension, creating forward and backward walls that increase the effective aperture area without requiring larger radial dimensions
3Ease of operation
If the closure member has offset portions, then greater apertures and more linear progressive trend are achieved, but the closure member structure becomes more complex
Solution Approach 1:
The asymmetric offset configuration with forward and backward walls creates a more linear and progressive opening action, improving ease of operation through better flow control characteristics
Solution Approach 2:
The offset portions are strategically positioned to create specific flow characteristics in different regions, with the central wall oriented at 45° to optimize the fluid passage properties
Data Source
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AI summary
The invention relates to a butterfly valve comprising a butterfly closure member cooperating with a valve seat, which valve seat has a substantially annular seal that, with the closure member in the closed position, adheres by a given compression force in the direction transversal to the flow direction and/or to the axis of the valve seat against the head peripheral edge of the closure member and/or by a given compression force in the flow direction against a front peripheral band. The valve further comprises a diametral shaft rotatably supporting the closure member from a closed position wherein the closure member is placed transversely to the flow direction and/or to the axis of the valve seat to a maximum open position with the closure member rotated by 90° with respect to said closed position. The closure member has portions offset in an opposite direction with respect to a plane passing by the axis of rotation of the diametral plane.