White Paper - Optimizing Plastic Pellet Conveying: The Enduring Superiority of DELTA DUCON’S SPIRA/flo® Pipe in Mitigating Angel Hair and Fines

Introduction

In the highly competitive plastics industry, the efficiency and integrity of raw materials are paramount to profitability and product quality. Plastic pellets, the fundamental building blocks of countless products, undergo rigorous handling processes, with pneumatic conveying being a cornerstone of modern manufacturing. However, this critical transport method often introduces a significant and persistent challenge: the formation of "angel hair" and fines. These unwanted byproducts, resulting from friction, shearing, and impact within conveying pipelines, lead to detrimental product degradation, increased maintenance demands, and noticeable operational inefficiencies. Addressing this issue is not merely an operational concern; it is a strategic imperative for maintaining product quality, reducing waste, and enhancing bottom-line performance.

At Delta Ducon, our legacy in bulk material handling spans over a century of continuous innovation. We have dedicated decades to developing specialized solutions that optimize conveying while preserving material quality, particularly for sensitive materials like plastic pellets. Our definitive answer to the angel hair dilemma is SPIRA/flo® Pipe, a unique, pressed groove pipe meticulously designed to significantly reduce the formation of these detrimental byproducts. The efficacy of DELTA DUCON’S SPIRA/flo® is not merely an assertion; it is a testament to documented, real-world performance, powerfully substantiated by a pivotal competitive test conducted by a leading polyethylene pellet producer. This white paper will revisit the compelling findings of that original test report to comprehensively demonstrate why DELTA DUCON’S SPIRA/flo® has remained the preferred choice for this major producer for over 45 years, and how its innovative design continues to set the standard for optimizing plastic pellet conveying in the most demanding industrial environments.

The Challenge of Angel Hair in Plastic Pellet Conveying

Angel hair, characterized by fine, fibrous strands of plastic, along with general fines, arises from the continuous friction and shearing action between plastic pellets themselves and between the pellets and the interior surfaces of conveying pipes.

This phenomenon is exacerbated by factors such as:

• High conveying velocities.

• Long conveying distances.

• Numerous bends and directional changes in the pipeline.

• The inherent friction characteristics of the polymer material itself.

• Static electricity buildup, which can cause pellets to adhere to pipe walls, intensifying rubbing.

  
  

The consequences of angel hair and fines accumulation are substantial for plastics manufacturers:

• Product Degradation: The presence of angel hair and fines can compromise the aesthetics and physical properties of the final plastic product, leading to off-spec material and increased scrap rates.

• Reduced Throughput and Efficiency: Angel hair can build up on pipe walls, reducing the effective cross-sectional area and increasing pressure drop, thereby hindering material flow and decreasing conveying efficiency.

• Equipment Fouling and Clogging: Accumulations of angel hair can clog filters, screens, cyclones, and processing equipment (e.g., extruder feed hoppers), necessitating frequent shutdowns for cleaning and maintenance.

• Increased Maintenance Costs: Regular cleaning, pipe replacements, and equipment repairs directly impact operational budgets.

• Safety Hazards: Dust created by fines can pose an explosion risk for certain plastic materials, and manual cleaning of clogged systems can expose workers to hazards.

  
  

The Pivotal Competitive Test: A Benchmark for Performance

Recognizing the critical nature of the angel hair problem, a prominent polyethylene pellet producer initiated a rigorous competitive test. This comprehensive evaluation, conducted in January, aimed to identify the most effective pipe interior for mitigating angel hair formation during pneumatic conveying. The goal was to secure a solution that would preserve product quality and enhance operational efficiency.

The test program meticulously compared four distinct types of pipes:

• Smooth wall pipe

• Dimpled/Shot peened pipe

• Cut groove pipe

• DELTA DUCON’S SPIRA/flo® Pipe

  
  

Methodology and Setup: The tests were executed at the producer's dedicated pneumatic conveying test facility. Adherence to strict standardization ensured a fair and consistent comparison, with the pipe's internal surface being the sole variable. TR635 pellets were consistently used across all test runs. The system operated as a push-pull setup, enabling continuous operation for a sufficient duration to reliably induce angel hair formation under controlled conditions.

The conveying line comprised approximately 225 equivalent feet of 2-inch pipe, incorporating 50-foot straight sections and four 90-degree bends. To simulate challenging real-world conditions that can intensify angel hair production, two of the bends were heat-taped, and all piping was insulated with a 1-inch layer of fiberglass. Each test run was precisely five hours in duration. To ensure significant angel hair generation, particularly given the cold weather during the test period, high conveying velocities were maintained: a pick-up velocity of 7,000 feet per minute and a discharge velocity of 8,260 feet per minute, utilizing 235 SCFM of conveying air.

While equipment for quantitative measurement of angel hair by weight or volume was unavailable at the time, its presence was thoroughly assessed by visual observation of the pipe walls and the angel hair remover discharge. This qualitative assessment provided clear and compelling evidence of performance differences.

Key Findings and Performance Analysis:

The test results unequivocally demonstrated DELTA DUCON’S SPIRA/flo® Pipe's superior performance in reducing angel hair and fines, offering a clear advantage for plastic pellet conveying. The verbatim report highlights the following:

1. Smooth Aluminum Pipe (Baseline Performance): The initial run, serving as the control, used a smooth aluminum pipe at a conveying rate of 4,800 pounds per hour. At the end of the five-hour run, pipe disassembly revealed extensive angel hair: approximately 90% of the straight sections and a notable 40% of the bends were heavily coated with a dense layer of angel hair. This established a critical baseline, underscoring the substantial challenge posed by angel hair formation in typical smooth-wall piping within plastics processing environments.

   
   

2. DELTA DUCON’S SPIRA/flo® Pipe (Full System Superiority): Following the baseline test, a run was performed using an all-DELTA DUCON’S SPIRA/flo® pipe configuration, maintaining the same blower RPM and piping arrangement. A feed rate of 4,000 pounds per hour was used.

   
   

   The results were truly remarkable, confirming a "dramatic reduction in formation of angel hair". Post-run visual inspection showed that only approximately 25% of the pipe interior was coated with angel hair. Crucially, the angel hair that did form appeared as distinct small, light, and loosely attached flakes (approximately 1/4" x 1/4"). The report specifically noted that these flakes were "very light and loosely attached to the pipe, so it appeared that it could be easily separated from the pellets in a cyclone". This is a vital distinction for plastics producers, as it indicates that any minimal angel hair formed would be manageable and would not significantly harm the final product quality or operational efficiency. The report's confident conclusion was that this pipe "would be satisfactory for plant operation".

   
   

   (Note: While the original report included tests on other competitive treatments, paragraphs relating to these were specifically removed from the exact transcription as per the producer's request. However, the overall summary of the test clearly highlighted SPIRA/flo® as the best performer among all pipes tested.)

   
   

3. Mixed Pipe Configuration (Insight into Angel Hair Origins): An additional, insightful test was performed using a mixed pipe setup: smooth aluminum pipe for the straight sections combined with DELTA DUCON’S SPIRA/flo® for the bends. The pipe configuration and blower RPM stayed consistent with previous runs, and a 4,000 pounds per hour rate was achieved.

   
   

   The results from this mixed setup provided valuable insight into where angel hair primarily forms: approximately 50% of the smooth straight sections were covered with angel hair, while only approximately 25% of the DELTA DUCON’S SPIRA/flo® bends were coated with the light 1/4" x 1/4" flakes. This outcome clearly showed that angel hair is produced in straight sections as well as bends. More importantly, it demonstrated that even when used with traditional straight piping, the presence of SPIRA/flo® in the bends significantly reduced angel hair formation. However, the overall level of angel hair production in this mixed setup was ultimately considered "unsatisfactory for plant use" , reinforcing the need for DELTA DUCON’S SPIRA/flo® throughout the entire conveying line.

   
   

The Verdict: DELTA DUCON’S SPIRA/flo® – The Preferred Choice for Plastic Pellet Quality and Efficiency

In summary, the test report delivered a clear and compelling verdict for plastics manufacturers: DELTA DUCON’S SPIRA/flo® pipe, when used in both straights and bends, "would be satisfactory for plant use". The report highlighted two key benefits directly relevant to the plastics industry:

1. Significant Reduction: The production of angel hair would be "significantly reduced" when SPIRA/flo® is used throughout the entire pneumatic conveying system. This directly translates to higher product yield and less waste.

2. Easy Separation: Crucially for plastics processors, the angel hair that might still form with SPIRA/flo® was of a specific type (light, loosely attached flakes) that "could readily be separated from the pellet stream". This minimizes post-processing challenges and helps ensure the purity of the final product.

   
   

The Science Behind SPIRA/flo®: A Delta Ducon Innovation for Plastics

What makes DELTA DUCON’S SPIRA/flo® Pipe so uniquely effective in reducing angel hair, a persistent issue in plastic pellet conveying? It's a testament to Delta Ducon's innovative engineering and deep understanding of material flow dynamics. The pipe features a unique, precisely engineered pressed groove interior. This distinctive design is critical for several reasons:

• Minimized Contact Area: Unlike smooth-wall pipes where pellets tumble randomly and maximize contact with the pipe surface, the spiraling grooves minimize the actual contact area between the pellets and the pipe wall. This reduces friction and the shearing forces that are primary causes of angel hair formation.

• Controlled Flow Path: The spiraling grooves gently guide the pellets along a more controlled path, significantly reducing direct impact against the pipe walls. This creates a smoother, less abrasive flow, which helps minimize the chaotic bouncing and rubbing that typically generate fines and angel hair.

• Reduced Static Buildup: The unique surface can also help reduce static electricity buildup, which can cause pellets to stick to the pipe wall and further worsen angel hair issues.

  
  

This innovative design was developed by Delta Ducon, LLC. The name SPIRA/flo® itself suggests the spiraling, optimized flow it creates, a direct result of decades of research, development, and real-world application in pneumatic conveying.

Delta Ducon's Legacy of Performance in Plastic Pellet Handling

The test was not just a historical event; it marked the beginning of a long-standing, successful partnership. The impressive and documented performance shown by DELTA DUCON’S SPIRA/flo® Pipe in that key trial has made it the preferred choice for that major polyethylene producer for over 45 years. This lasting relationship is strong evidence of the real-world benefits and long-term reliability that SPIRA/flo® provides in the demanding environment of plastic pellet conveying.

At Delta Ducon, our expertise extends thoroughly across all aspects of bulk material handling, with a specific focus on the subtle needs of the plastics industry. Our century of experience in handling highly abrasive materials across diverse sectors like cement, mining, minerals, steel, power, and building products, provides us with a unique and strong foundation. We use this deep knowledge to bring a complete understanding to pneumatic conveying systems for plastics. We specialize in designing, manufacturing, and installing complete conveying solutions that prioritize:

• Product Integrity: Our main focus is on minimizing product degradation, angel hair, and fines, ensuring your plastic pellets keep their quality from the railcar to processing.

• Operational Efficiency: We engineer systems for consistent, high-volume flow, optimizing throughput while aiming for reduced energy use.

• System Longevity: Using extremely strong components, including our patented SPIRA/flo® pipe, we ensure your conveying system withstands continuous, demanding operation for decades.

• Reduced Maintenance: Our designs emphasize reliability and ease of maintenance, leading to less downtime and lower operational costs—a critical factor for any plastics manufacturer.

  
  

Whether you're conveying polyethylene, polypropylene, PVC, or other types of plastic pellets, powders, or granular materials, the fundamental principles of minimizing friction, impact, and shearing forces are universal and crucial for product quality. Delta Ducon's dedicated engineering team uses this deep knowledge to custom-design pneumatic conveying systems that meet your exact needs. This ensures your material handling operations are not just efficient but are optimized for product quality and long-term reliability.

The proven performance of DELTA DUCON’S SPIRA/flo® Pipe stands as a clear example of Delta Ducon's commitment to innovation and engineering excellence in bulk material handling. For operations where material quality, conveying efficiency, and system longevity are essential, trust the lasting performance of DELTA DUCON’S SPIRA/flo® and the expertise of Delta Ducon.

Conclusion

The challenge of angel hair and fines in plastic pellet conveying is a significant hurdle for plastics manufacturers, impacting product quality, operational efficiency, and overall profitability. As demonstrated by the rigorous competitive testing, DELTA DUCON’S SPIRA/flo® Pipe offers a uniquely effective solution. Its innovative pressed groove design dramatically reduces angel hair formation and ensures that any minimal byproducts are easily separable, preserving product integrity. With over 45 years of proven performance in the field, SPIRA/flo® continues to be the preferred choice for leading producers, underscoring Delta Ducon's century-long commitment to engineering excellence in bulk material handling. By choosing DELTA DUCON’S SPIRA/flo®, plastics manufacturers can achieve superior material quality, reduce maintenance demands, and ensure the consistent, efficient operation of their conveying systems.

For more information on how DELTA DUCON’S SPIRA/flo® Pipe can optimize your plastic pellet conveying operations, please visit www.spiraflopipe.com or contact our engineering team directly.

Delta Ducon, LLC  11 General Warren Blvd. Malvern, Pa 19355-1216 U.S.A Phone: 610.695.9700 Toll Free: 1.800.238.2974 Fax: 610.695.9724 www.spiraflopipe.com