Slew Ring Support for Rotary Drum Sorting
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Solution Overview
Problem
Traditional rotary drums used in material separation, such as trommels, face limitations in rotational speed due to hysteresis and friction, leading to heat buildup, mechanical stress, and inefficient utilization of space, with ride ring and caster systems being heavy, costly, and complex, and requiring additional mechanical components for axial loading.
Innovation Solution
The use of large-diameter multi-race bearings, specifically slew rings, where the outer race remains fixed and the inner race rotates with the drum, reducing the rotating weight and allowing higher rotational speeds and larger diameters, increasing screen utilization ratios and reducing component wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ride ring and caster systems are used to support the rotary drum, then the drum can be supported and rotated, but the system becomes very heavy, complex, and costly with significant weight added to the rotating mass
Solution Approach 1:
The support system is segmented into multiple independent roller assemblies distributed along the drum circumference, with each roller carrying a portion of the drum weight. This segmentation allows the use of lighter individual components while maintaining overall support capability, reducing the total weight of the support system compared to traditional heavy ride rings and casters.
Solution Approach 2:
The traditional mechanical friction-based caster system is replaced with a roller-based system that reduces friction and weight. The rollers rotate freely to support the drum, eliminating the need for heavy casters and ride rings while enabling smoother rotation and reducing the moment of inertia of the rotating mass.
2Productivity
If the rotary drum operates at higher rotational speeds to improve productivity, then separation efficiency increases, but heat buildup and mechanical stress increase due to hysteresis and friction
Solution Approach 1:
The friction-based caster system is replaced with a roller support system that significantly reduces friction and hysteresis losses. The rollers rotate freely with minimal contact friction, allowing the drum to operate at higher speeds without excessive heat generation from mechanical friction and material hysteresis.
3Productivity
If the drum diameter is increased to improve separation capacity, then more material can be separated simultaneously, but the weight and complexity of the support system increase significantly
Solution Approach 1:
The support system for large-diameter drums is segmented into multiple distributed roller assemblies, allowing the drum weight to be supported by multiple light components rather than a single heavy support structure. This enables the use of larger drum diameters for increased separation capacity without proportionally increasing support system weight and complexity.
4Reliability
If traditional casters are used to support the drum, then the drum can be rotated, but additional mechanical components such as thrust rollers are required to handle axial loading
Solution Approach 1:
The roller assemblies are designed to perform multiple functions: supporting radial drum weight, accommodating axial thrust loads from inclined operation, and enabling free rotation. This multi-functionality eliminates the need for separate thrust rollers and other additional mechanical components required in traditional caster-based systems.
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 enables rotary drums to operate at higher speeds with improved utilization ratios, reduced weight and cost, and increased separation efficiency in a given space, while minimizing mechanical stress and heat buildup.
Implementation Method 1
Traditional rotary drums used in material separation, such as trommels, face limitations in rotational speed due to hysteresis and friction
Implementation Method 2
Traditional rotary drums used in material separation, such as trommels, face limitations in rotational speed due to hysteresis and friction
Implementation Method 3
ball or roller bearings used in the multi-race bearing are able to run at significantly higher speeds than traditional caster systems
Data Source
AI summary
A rotary sorting apparatus comprises a large-diameter rotary drum for sorting a mixture of materials received through a first end of the drum and expelled through a second end. A plurality of slew rings are attached circumferentially to the outer surface of the drum for supporting and rotating the drum. Each slew ring comprises an inner race placed concentrically within an outer race, with bearings between them allowing the inner race to rotate freely within the outer race. The inner surface of the inner race is attached to the outer surface of the drum and rotates with the drum, while the outer surface of the outer race is fixed to the supporting structure. A rotator, such as a wheel, in contact with the outer surface of the drum causes the drum to rotate about its longitudinal axis.