Pneumatic Conveying Expanded Elbows for Pellet Damage Reduction
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Solution Overview
Problem
Pneumatic conveying systems for particulate materials, such as plastic pellets, often result in damage and contamination due to high friction and directional changes, leading to the generation of dust, streamers, and debris, which can cause defects in the final product and increase maintenance costs.
Innovation Solution
A process utilizing expanded elbow fittings at pipe bends and rotary valves to minimize damage and contamination, combined with a dedusting apparatus for final cleaning before product delivery, operating at medium velocities and pressures to reduce dust and debris formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high velocity dilute phase conveying is used to increase productivity, then conveying speed increases, but particle damage and contaminant generation increase
Solution Approach 1:
The patent changes the conveying parameters from high velocity/dilute phase to medium velocity/dense phase operation. Specifically, it operates at velocities of 15-25 m/s and pressures of 0.5-2.0 bar, maintaining a dense phase where particles remain in contact with each other and the pipe wall, thereby reducing relative motion and contaminant generation while preserving productivity
Solution Approach 2:
The patent converts the typically harmful wall friction and particle-particle friction in dense phase conveying into a beneficial effect. By maintaining dense phase operation, the friction between particles and wall actually protects particles from the more damaging high-velocity impacts and turbulence that occur in dilute phase conveying, reducing streamer formation and particle breakage
2Object-generated harmful factors
If slow motion dense phase conveying is used to reduce particle damage, then particle contamination decreases, but conveying efficiency decreases
Solution Approach 1:
The patent optimizes the parameters of dense phase conveying by operating at medium velocities (15-25 m/s) rather than slow velocities, and at moderate pressures (0.5-2.0 bar). This parameter optimization maintains the protective dense phase conditions that reduce contamination while improving conveying efficiency compared to traditional slow dense phase systems
3Object-generated harmful factors
If expanded elbow fittings are used at pipe bends, then directional changes become gentler, but device complexity increases
Solution Approach 1:
The patent employs expanded elbow fittings with increased curvature radius at pipe bends. These fittings provide a gentler transition for the particle-laden air stream, reducing abrupt directional changes that cause particles to impact the pipe wall and form streamers. The expanded curvature allows particles to follow the bend more smoothly, minimizing damage despite the added component complexity
4Manufacturing precision
If medium velocity conveying is used to minimize dust and streamers, then product quality improves, but conveying time increases
Solution Approach 1:
The patent achieves optimal product quality by operating at medium velocities (15-25 m/s), which is faster than traditional dense phase conveying. This medium velocity range reduces particle damage and contaminant generation compared to high velocity systems while maintaining shorter conveying times than slow dense phase systems, thus improving product quality without excessive time penalty
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 process effectively minimizes damage and contamination during conveying, ensuring high-quality products by reducing dust and streamers, and maintaining system flexibility and low maintenance costs through gentle and efficient conveying and cleaning.
Implementation Method 1
As these materials move through the pipes, considerable friction is generated not only between the particles themselves (referred to as internal friction), but also between the tube walls and the particles in the stream (referred to as wall friction)
Implementation Method 2
A dedusting apparatus is used to provide a final cleaning of the plastic pellets before they are delivered to the ultimate utilization of the plastic pellets
Data Source
AI summary
A pneumatic conveying process transports plastic pellets from a manufacturing source to a bulk silo for storage before being delivered to the ultimate production utilization of the plastic pellets. Multiple types or multiple sources of plastic pellets can be fed through a common pneumatic conveying conduit to respective bulk silos for temporary storage with diverter valves being utilized to direct product into and out of the common conveying conduit. Expanded elbow fittings are deployed at each directional change in the conveying lines to eliminate the creation of streamers at conduit bends. The plastic pellets are conveyed at a medium velocity between dense and dilute phases to provide a gentle conveying operation. A closed loop air supply system is used for dedusting devices providing a final removal of dust and debris from the stored product before being delivered to the ultimate utilization facility.