Spiral Core Ribs for Mixer Rotor Fatigue Reduction
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Solution Overview
Problem
Large internal batch mixers experience fatigue failure due to stress concentration in areas with straight core ribs, leading to water leakage and contamination of the mixing material, necessitating an improvement in rotor design to extend working life.
Innovation Solution
The design incorporates a rotor with internal reinforcing ribs of spiral or curved configuration that project into the cavity, reducing stress concentration and improving cooling efficiency, thereby enhancing the rotor's durability and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If straight core ribs are used in the rotor, then the manufacturing process is simple, but stress concentration occurs leading to fatigue failure
Solution Approach 1:
The patent applies curvature by replacing straight core ribs with spiral or curved core ribs that follow a helical path around the rotor axis. This curvature distributes stress more evenly across the rotor structure, eliminating stress concentration points that occur with straight ribs, thereby preventing fatigue failure while maintaining manufacturing feasibility through standard casting processes
2Reliability
If spiral core ribs are used, then stress concentration is reduced and rotor life is extended, but manufacturing complexity increases
Solution Approach 1:
The patent changes the geometric parameters of the core ribs from straight to spiral configurations, defining specific helical paths with controlled radius and pitch. This parameter modification optimizes stress distribution throughout the rotor, extending service life by 32.5% compared to no ribs and 19.1% compared to straight ribs, while the complexity remains manageable through standardized design templates
3Strength
If core ribs are added to the rotor, then structural strength is improved, but the rotor weight increases
Solution Approach 1:
The patent applies local quality by positioning core ribs strategically at specific locations within the rotor cavity where stress concentration is most likely to occur. The spiral ribs are distributed along the rotor length and circumference at optimal positions to provide maximum structural reinforcement with minimum material addition, achieving strength improvement while minimizing weight increase
Data Source
AI summary
An improved rotor design is provided for an internal batch mixing machine. A rotor has a rotor body with an axially extending central cavity, and with a plurality of mixing wings defined on the outer surface of the rotor body. A plurality of internal reinforcing ribs of generally spiral or curved configuration are defined on the rotor body and project into the cavity.