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Material Handling in Manufacturing: The Dense Phase Pneumatic Conveying Advantage

Dense Phase Pneumatic Conveying in Bakery Flour Processing

by: Michael Thiel and Jacob Dailey

In the manufacturing processes, the movement and management of dry powders play a pivotal role in the production lifecycle. Industries ranging from food production to high-tech manufacturing rely on the efficient transfer of ingredients like flour, sugar, and various powders such as polyethylene, aluminum oxide, or carbon black. However, the challenge lies not just in the movement but in doing so effectively, efficiently, and without compromising the integrity of the materials. Here is where the dense phase pneumatic conveying advantage becomes evident, offering a superior method that surpasses traditional mechanical and manual conveying approaches. 

The Quest for the Optimal Conveying Method

Traditional methods of transporting powders, such as manual handling and mechanical conveyors, often fall short in terms of efficiency, cost, and practicality, especially over longer distances. Mechanical systems, for instance, come with a high maintenance burden and can struggle with the complexities of installation across expansive manufacturing floors.

Enter pneumatic conveying, a technology that leverages air to move powders through pipelines. However, this method is not without its pitfalls, as the high air pressure required can sometimes jeopardize the powder’s quality.

Rendering of the Vacuum dilute phase pneumatic conveying system

Dense Phase Pneumatic Conveying: A Superior Approach

Dense phase pneumatic conveying emerges as a standout solution, overcoming the limitations of other methods. Characterized by its high solid-to-air ratio and lower velocity, it ensures the gentle handling of materials, significantly reducing the risk of damage or degradation. This system is particularly suited for materials with low permeability, though advancements have made it possible to convey even high-permeability materials like plastic pellets effectively.

The Engineering Behind Dense Phase Conveying

Dilute-phase conveying involves the suspension of powder or material within the pipeline, allowing for swift movement. This method is particularly advantageous when dealing with sturdier, non-abrasive materials with a low bulk density. The rapid conveyance facilitated by dilute phase systems is well-suited for applications where quick and efficient movement of materials is paramount.

Dense Phase

Implementing a dense phase pneumatic conveying system requires a pressurized tank capable of withstanding 40-60psig, equipped with multiple air inlets and a pressure relief valve to manage unexpected pressure surges. Key components include a filter receiver and, potentially, a level sensor to prevent overfilling, ensuring smooth and continuous operation.

Advantages and Considerations of Dense Phase Conveying

The benefits of opting for dense phase conveying are numerous, from eliminating mechanical parts within the convey line and simplifying maintenance to the system’s flexibility in routing and distance coverage. However, technology is not without challenges. The potential for material damage due to excessive speed or pressure within the convey line necessitates careful system design and operation.

Tailored Solutions for Diverse Needs

Beyond fragile powders, dense phase conveying is also adept at handling abrasive materials, thanks to components like the dome valve, which is designed to withstand the rigors of such applications. This flexibility underscores the technology’s versatility and applicability across a broad spectrum of industries.

HaF’s Excellence in Pneumatic Conveying Systems

In material handling and conveyance, customization and innovation are key. At HaF Equipment, we specialize in designing pneumatic conveying solutions tailored to the unique needs and challenges of manufacturers. By collaborating with experts in the field, manufacturers can enhance productivity, reduce operational costs, and achieve unparalleled product quality.

Implementing dense phase pneumatic conveying represents a strategic move toward operational excellence in manufacturing. With its combination of efficiency, gentle handling, and versatility, it stands as a testament to the power of innovation in overcoming the complexities of modern production processes to become a system of efficiency, accuracy, and customization. As industries continue to evolve, the demand for customized solutions in handling bulk materials will only grow stronger, and HaF is prepared to lead the way.

ABOUT HaF

HaF Equipment offers turnkey services for projects big and small. Our team understands the concerns of our customers and takes the time to listen. We develop a plan and communicate along the way. If you need someone you can trust and want to eliminate the stress of managing all the details of your next project, HaF is Ready To Connect.

CONTACT US today to discuss your next project and how our team can help from concept to system solution.

Pneumatic Conveying in Transporting Dry Bulk Materials 

Pneumatic Conveying Vacuum Dense Phase - HaF Equipment - Bulk Material Handling Equipment Pet Food Production

Pneumatic conveying in material handling is a highly efficient method of dry bulk material transport through a network of airtight pipelines. In this bulk conveying system, air is used as the medium to propel the materials from one location to another, eliminating the need for manual handling or traditional mechanical transport methods.

Key Advantages of Pneumatic Conveying Systems

  1. Pneumatic conveying prevents contamination. The airtight nature of the pipelines ensures that no external elements can come into contact with the materials during transit. This makes it an ideal choice for industries where maintaining product purity is essential, such as pharmaceuticals and food processing.
  2. Pneumatic material handling systems offer flexibility in terms of distance and direction. The materials can be transported horizontally and vertically, allowing tricky layout constraints to be mitigated. With proper design and sizing of the pipelines, long distances can be covered without compromising efficiency.
  3. Pneumatic bulk conveying systems enable quick and convenient transfer between multiple points within a facility. Automatic controls allow for easy redirection of material flow, allowing operators to direct materials to different processing units or storage locations as needed.
  4. Pneumatic conveying minimizes material degradation and loss. Unlike mechanical conveyors that often subject materials to excessive friction or impact forces, pneumatic conveying gently handles fragile goods like powders and granules, ensuring their integrity remains intact throughout transportation.
  5. Pneumatic material handling systems require fewer moving parts. With only a blower to provide the air to move the product, there are no long chains or belts to worry about wearing out. 
Vacuum Dense Phase Equipment for pneumatic conveying in Bulk Material Handling.

Dilute Phase and Dense Phase Pneumatic Conveying Systems

Pneumatic conveying systems are classified into two main categories: dilute phase and dense phase. The nuanced differences between these bulk conveying systems play a pivotal role in efficiently handling different types of materials.

Dilute Phase

Dilute-phase conveying involves the suspension of powder or material within the pipeline, allowing for swift movement. This method is particularly advantageous when dealing with sturdier, non-abrasive materials with a low bulk density. The rapid conveyance facilitated by dilute phase systems is well-suited for applications where quick and efficient movement of materials is paramount.

Dense Phase

In contrast, dense phase conveying utilizes pressurized air to move materials more slowly, making it ideal for fragile substances such as coffee beans, cereals, and pet kibble. The controlled and gentle movement provided by dense phase conveying proves crucial for maintaining the integrity of delicate materials, ensuring they reach their destination intact. 

Moreover, dense-phase conveying systems go beyond fragility considerations. They are essential for transporting abrasive particles and preventing wear on pipes. Additionally, heavy materials that require substantial energy to be entrained in the air stream benefit significantly from the controlled movement facilitated by dense phase conveying.

Dense-phase conveying systems also play a crucial role in conveying blended and batched materials. This ensures that powders remain homogenous throughout the transportation process, mitigating the risk of separation in the air stream. This contrasts dilute phase systems, where varying particle sizes and bulk densities may lead to distinct segregation during conveyance.

Industries That Rely on Pneumatic Conveying

Pneumatic conveying systems play a vital role in numerous industries, offering efficient and reliable bulk material transport. Following are a few industries that rely heavily on these systems:

  1. Pharmaceutical Sector. Pneumatic conveying enables the safe transfer of sensitive powders and granules without risk of contamination or cross-contamination.
  2. Food Processing Industry. Pneumatic conveying facilitates the gentle handling of fragile and perishable food products such as spices, flour, and sugar, ensuring their quality remains intact throughout transportation.
  3. Chemical Manufacturing. Pneumatic conveying enables swift and precise movement of hazardous substances like fine chemicals and detergents. The enclosed nature of these systems ensures worker safety by eliminating exposure to harmful substances. These bulk conveying systems can even be designed in closed-loop scenarios with inert gasses such as nitrogen. 
  4. Construction Industry. Pneumatic conveying transfers cement, sand, and other fine aggregates quickly and efficiently. The ability of bulk material transport over long distances using pipelines allows for seamless operations at construction sites.

Overall, pneumatic conveying systems offer flexible solutions across various industries by providing efficient material transportation that meets specific needs. With continuous advancements in technology and design, these dry bulk material handling equipment continue to revolutionize industries worldwide.

HaF’s Excellence in Pneumatic Conveying Systems

HaF Equipment stands out for its expertise in pneumatic conveying. Under HaF’s skilled guidance, pneumatic conveying goes beyond being a simple method of material transport; it becomes a system of efficiency, accuracy, and customization. As industries continue to evolve, the demand for customized solutions in dry bulk material handling will only grow stronger, and HaF is prepared to lead the way.

ABOUT HaF

HaF Equipment offers turnkey services for projects big and small. Our team understands the concerns of our customers and takes the time to listen. We develop a plan and communicate along the way. If you need someone you can trust and want to eliminate the stress of managing all the details of your next project, HaF is Ready To Connect.

CONTACT US today to discuss your next project and how our team can help from concept to system solution.

Airlocks and Pneumatic Conveying

Airlocks and Pneumatic Conveying

by Dan Fried and Devon DeJong

Does your mind go straight to the scene of your favorite Syfy movie when someone mentions airlocks – where the hero (or villain) is trapped between safety and being sucked out into deep space at the press of a button? We like a good science fiction movie, too, but airlocks in pneumatic conveying get us just as excited!  

An airlock is a compartment with doors that can be sealed against pressure which permits the passage of people and objects between environments of differing pressure or atmospheric composition while minimizing the change of pressure in the adjoining spaces and mixing of environments. The airlock consists of a relatively small chamber with two airtight doors in series which do not open simultaneously. (Source) 

In pneumatic conveying, airlocks are the passageways that bulk materials use to move between environments consisting of different pressures, gases, or both, with the goal being to minimize pressure loss and to prevent the gases from mixing. (In pneumatic conveying, airlocks are used for passage between various environments of different materials like gases, or different pressures, or both, to minimize pressure loss or prevent the gases from mixing). Airlocks are a critical component of pneumatic conveying designs. When applied to conveying, the objective is to move bulk material across a pressure differential; low to high (Pressure Conveying) or high to low (Vacuum Conveying). 

How airlocks work can sound complex; however, the design is simple. When a product drops into a pocket on the top, the rotor spins and drops the product out the bottom. The rotor has VERY tight tolerances with the housing to prevent air or the product from blowing past the rotor tips. (A typical airlock will come with a rotor tip-to-housing clearance of between .004” and .007”; Once that clearance is above .0079″ it is no longer NFPA compliant). An airlock prevents air leakage across the pressure differential.

Airlocks Used in Bulk Material Handling

Drop-through airlock. What is beneficial about this airlock is that the cost is lower because it is more widely available. The downfall to the drop-through airlock is the head height. 

Drop-through airlock with rails. Customers appreciate this airlock because it is operator and maintenance-friendly. The drawback to this airlock is the cost on the application’s front end. 

Blow-through airlock. Compared to the drop-through airlock, the blow-through lock is preferred because of its head height and the feature that no pick-up shoe is needed. The blow-through airlock is avoided at times because of the cost and the few options it provides.

Airlocks and NFPA Compliance

Airlocks are one of the most important components of an equipment’s success. Knowing the application will determine whether the airlocks need to be NFPA Compliant.

The National Fire Protection Association is an organization that is devoted to eliminating death, injury, property, and economic loss due to fire, electrical and related hazards. The NFPA Codes & Standards states that the airlock has a minimum of 8 vanes. At least two vanes must always stay in contact with each side of the housing, and the vanes must be at least 3mm thick. This helps keep flames contained to the rotor pocket if there is an explosion. Plastic or rubber tips are not NFPA compliant, as they will not hold up to the heat of an explosion. It’s also important to know that rotor-to-housing clearance must stay below .0079″ (0.2mm).

SELECTING AN AIRLOCK

Many factors go into selecting the right airlock for a project. Knowing the environment to which the airlock will be exposed is a vital consideration.

  • Temperature is a key factor, so it is important to know if the airlock will be indoor or outdoor, and the temperature of the material being conveyed.
  • Pressure above or below the throughput needs makes a difference.
  • Product details surrounding the airlock need to be considered to select the proper airlock; i.e. bulk density, angle of repose, flowability, abrasiveness and explosiveness are all product characteristics that can affect the airlock.

When questioning which airlock is best suited for a project, consider the airlock itself; body type, body material, rotor style/material, inboard vs. outboard bearings, and gland vs. air purge shaft seal play into what airlock will perform the best.

There are many options to rotary airlocks.

  • The shallow pocket types reduce the volume per requirement and are generally used on filters, cyclones and silos.
  • A staggered pocket rotor has a continuous and uniform flow to provide a more accurate rate of material flow.
  • Fine Dosing rotors are beneficial when feeding or discharging fine powders, materials or granules that are contained in hoppers and silos.
  • A scalloped rotor is best suited for sticky materials or food-grade applications.
  • Flexible tip rotors are helpful when trying to avoid jams in the valve and are more suited for dust filters than food-grade applications.
  • Consider an adjustable rotor when handling more abrasive material.

Airlocks can also offer a variety of features.

A low-cost feature with a high reward is a shaft seal air purge. A shaft seal air purge will prevent material from entering the seals and bearings.

A Zero Speed Switch is a valuable feature where it alerts the system if the rotor stops spinning, jams, or breaks.

Although they have a high price point, Slider Rails allows access for cleaning and maintenance.

The material and the coating of an airlock is critical. Nickel plating, chrome plating, and tungsten coating all help prevent premature wear of the airlock. 

Factors, options, and features of airlocks can be overwhelming. Working with a skilled team of knowledgeable engineers in the field can help. With over 25 years of experience, HaF Equipment is that team Ready To Connect!

Summary:
HaF Equipment is here to assist you with which application would benefit from pneumatic conveying; and seeing is believing. So, contact a HaF account manager today to see what options we can provide you. 

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