Coffee Conveyor Selection Guide

Looking for the right conveyor for your coffee product? Manufacturers and roasters are moving away from using traditional, open bucket elevators and belt conveyors for moving ground coffee and coffee beans due to both hygienic and layout challenges. Instead, coffee producers are opting for more efficient, hygienic, totally-enclosed and flexible conveying systems.

Enclosed, hygienic coffee conveyor options include flexible screw conveyors, aeromechanical conveyors and tubular cable drag conveyors.

But which conveying system is right for your coffee product? The type of coffee product you wish to convey, the coffee product end customer (ie. commercial vs. specialty – how much does whole bean breakage matter?), operational needs (ie. energy efficiency), budget and facility layout must all be considered.

Coffee Conveying Considerations by Product

Green unroasted beans, roasted whole beans, ground coffee and coffee mixes all come with characteristics and challenges that must be considered when selecting the right conveying system.

Green, Unroasted & Roasted Whole Beans

Unroasted, or green, coffee beans are very fragile in their raw state. A gentle conveyor that minimizes bumping, twisting and grinding will be ideal to protect the beans from breakage. Broken beans means waste and wasted dollars early in the coffee production process, unless the beans can be separated and then delivered as a final ground product. Additionally, the conveyor will need to be constructed to hold up to the abrasive wear of processing whole beans.

Like green beans, roasted whole coffee beans are very fragile and thus must be processed gently to avoid degradation and breakage of the roasted beans. Additionally, freshly roasted beans need to be processed quickly and protected as much as possible from the environment surrounding the conveying machinery to preserve freshness and flavor in the end product.

Ground Coffee & Mixes

Ground coffee is hygroscopic (easily absorbs moisture) in nature and is thus prone to clumping. Additionally, dusting and dust control are of utmost importance when working with ground coffee or coffee mixes due to its combustible properties and for operator environment safety. For ground coffee, maintaining the consistency and size of the coffee grinds is also essential for brewing a good final product.

For coffee mixes, blend integrity can be maintained by using a conveyor that constantly re-mixes the coffee product and prevents separation. Additionally, conveying systems processing different types of flavored mixes or coffees may need to be frequently changed out and quickly and thoroughly cleaned between changes to prevent flavor cross-contamination.

Comparing Totally-Enclosed Coffee Conveyor Options

Flexible Screw Conveyors

Flexible screw conveyors use a spiral or auger inside of an enclosed tube to convey the product up the tube at any angle, including around slight bends. These conveyors are low maintenance and low cost solutions. A flexible screw conveyor is ideal for maintaining continuous blends due to the constant remixixing of the spiral as the product is conveyed. Thus, the flexible screw conveyor may be an option for coffee granules or mixes.

However, the spiral action can be aggressive and may not be the most suitable solution for conveying friable coffee beans. That being said, for some applications, the flexible screw conveyor may still be a good choice due to the unique requirements. Additionally, many manufacturers offer different types of spirals to best suit your applications.

Screw conveyors may also pose limitations when complex layouts with multiple planes are necessary due to the simple linear nature of their design. Thankfully, there are other conveying options that provide more flexibility, discussed below, where layout is a challenge.

Aeromechanical Conveyors

Aeromechanical conveyors operate using evenly spaced discs traveling at speed which creates an air stream to convey the coffee along with the discs. Totally-enclosed aeromechanical conveyors are a good option for conveying ground coffee due to their dust-free operation and enclosed design protecting the product from outside moisture.

The aeromechanical conveyors’ stainless steel construction and easy-to-clean features helps to reduce flavor cross-contamination if used for different batches of coffee. The aeromechanical conveyor offers fast and efficient conveying for any product, using relatively minimal horsepower.

However, due to the high speeds at which aeromechanical conveyors do run, there is a risk of product degradation and material breakage for friable whole beans, especially at angles or bend in the conveyor layout. Additionally, the introduction of oxygen or air into a product can cause the product to degrade more quickly. As with any conveying solution, running the coffee product through the conveyor in a test lab to understand the operation and end product condition will be essential.

Read our Excelso Coffee aeromechanical case study: Read case study 1002

Tubular Cable Drag Conveyors: Best Overall

Tubular cable drag conveyors use evenly spaced FDA-accepted polyurethane discs attached to a stainless steel cable to gently drag product along inside an enclosed tube. Cable drag conveyors are quickly becoming the conveyor of choice for coffee processors due to minimization of product degradation being a top priority for whole beans. Cable drag conveyors offer a high throughput of 10s of 1000s of pounds per hour at lower and more steady speeds (vs. the aeromechanical or pneumatic conveying options) which prevents product degradation of friable whole beans. In addition tubular cable drag conveyors are extremely versatile from a layout perspective and can be used to pick-up material from a number of different sources and transport it over long complex routes to a number of different destinations.

Enclosed tubular cable drag conveyors also have the advantage of being hygienic and easy to clean when equipped with clean-in-place dry and wet wash options. Automatic rope tensioning can extend cable life to reduce the risk of downtime and maintenance costs. While these conveyors can represent a significant capital investment, the payback and return on investment can occur very quickly when considering the minimal downtime, ability to run multiple coffee product types on the same machinery and low maintenance requirements.

These factors can make Tubular Drag Conveyors an ideal choice for manufacturers needing to convey both whole bean and ground coffee. Read our Eight O’Clock coffee tubular drag conveyor case study: Read case study 1023

Test, test, test

Finding a conveyor manufacturer that offers test lab facilities is essential for conveyor selection. Our engineers always recommend testing your coffee product to mimic your facility’s conditions and selected equipment before purchasing. Contact Spiroflow’s engineers to set up a materials test for your application.

SUGAR CONVEYING CHALLENGES: GRANULATED VS. POWDERED SUGAR

Powdered sugar is highly flammable and explosive. Sugar conveying system design should work to eliminate this risk. In fact, due to recent industrial accidents, government regulatory bodies like OSHA (Occupational Safety and Health Administration) and NFPA (National Fire Protection Association) have issued heightened regulations governing the handling of sugar. In addition, these agencies have labeled sugar processing facilities high risk.

Furthermore, powdered sugar tends to pack and cake as it is conveyed. Flow aids should be considered as part of the conveying system to help with discharging.

Granulated sugar, on the other hand, is abrasive. The sugar conveying system design should be able to withstand the wear of the sugar against its sides.

Like powdered sugar, granulated sugar is highly combustible, potentially explosive and will ignite at high temperatures. Conveyor design should prevent dust emissions and static buildup, and eliminate possible sources of ignition.

Finally, granulated sugar is a hygroscopic material, meaning it easily absorbs moisture. Conveyor system flow aids are usually necessary to ensure complete discharge of the sugar from the conveying system.

IDEAL SUGAR CONVEYORS AND CONVEYING SOLUTIONS

Aeromechanical Conveyors

The totally-enclosed aeromechanical conveyor is an ideal choice for conveying large volumes of both powdered and granulated sugar. Any dust created during conveying is contained within the conveyor, reducing the risk of explosions caused by static build up and sugar dust clouds.

In addition to being airtight, it runs quietly and with minimal energy.

Aeromechanical conveyors can be easily disassembled for regular, quick cleaning. This is essential for sugar, which is both prone to caking and build-up and often food product-bound.

Flexible Screw Conveyors

The flexible screw conveyor (FSC) is ideal for conveying batches of sugar.

The flexible screw works well with combustible materials as it is always full of product, preventing an explosive atmosphere. A flexible screw conveyor can come with a reverse bung, drop out tray and quick release flanges for best-in-class hygiene and cleaning and will help avoid cross-contamination when changing batches. Watch our video about hygienic flexible screw conveying and how it could benefit your sugar conveying process.

Additionally, the flexible screw’s spiral constantly remixes sugar as it conveys to maintain product integrity. Some over-the-counter health products are mixtures of very fine active components mixed with a coarse grade of sugar. To ensure every sachet is the same, many health product packing lines use FSCs as the final conveying technology so that every packet contains the same formulation.

Flexible screw conveyors conveying sugar should be constructed from materials that can stand up to the abrasion. Heavy-duty spirals are available and, in extreme cases, double wind spirals can be used. We often recommend stainless steel or rubber Rhinoveyor tubing as more wear resistant options over the standard UHMWPE tube. An undersized screw can also be placed in a conveyor to reduce tube wear. This allows more clearance between the spiral and tube allowing the material to act as a buffer between the two.

Support For Your Sugar Conveying System

Interested in how we can help reduce manual handling and increase the efficiency of your sugar conveying and processing system?  Contact our Spiroflow engineers today.

This is installment #1 in Spiroflow’s 4-part blog series: “Making Manufacturing Shifts: Adapting During COVID-19 & Beyond” In this blog, we will provide an overview of COVID-related impacts to industrial manufacturing and address the first shift: modifying production lines for new products. 

The overall impact of the coronavirus outbreak to global industrial manufacturing has been a reduction in demand and a resulting decline in production output. But select industries – food & beverage, snack foods, pharmaceuticals and chemicals – are now faced with the opposite problem: finding a way to increase production and packaging capacity – all while keeping workers safe and adhering to regulations and restrictions. 

Cleaning supplies, toilet paper, dry goods, frozen foods and snack foods – these are just a few examples of products that have been in high demand as a result of quarantine purchasing behaviors. And as a result of sudden demand not planned for, manufacturers are struggling to keep pace. Adding to the 24/7 challenge are staffing concerns and compliance with social distancing and stay-at-home orders. 

In talking with Spiroflow customers, we have identified 4 common challenges that require operational changes on the site floor. 

Shift #1: Modifying Existing Production Lines for a Different Product 

Through our series, we will examine each shift in terms of: industry examples, benefits, expectations for time needed to make the modification, safety and compliance. Today we will take a closer look at shift #1: modifying existing production lines in order to process a different product. 

Why would I modify my production line during COVID?

If COVID regulations and conditions mean that product orders have dried up, your business may want to evaluate cost-effective modifications that can be made to your existing production line and begin manufacturing an in-demand product. 

For example, Spiroflow has worked with a number of distilleries who have modified their production line to produce hand sanitizer. In Japan, Sharp electronics has started making surgical masks at production facilities previously used to manufacture LCD display panels. Clothing manufacturers are shifting from normal clothing items to producing hospital gowns. There are many other modifications being made on global production lines to adapt to changing demand. 

Keep in mind that some modifications may mean sourcing new materials or ingredients, which may prove challenging and require guidance on testing. Please contact Spiroflow to discuss modification options.

I need to keep my operation running 24/7. How much downtime can I expect while equipment modifications are made?

Our team is dedicated to getting permanent installations up and running as quickly as possible, but our flexible, mobile conveying systems allow us to modify your production line even faster. While installation times vary by operation, a simple modification, such as a conveyor upgrade or addition of a bulk bag filler can take place in under a day, in some cases in as little as a few hours. Spiroflow manufactures 9 sizes of flexible screw conveyors to easily fit your existing process. 

This means less downtime when you most need your operation to continue without interruption. 

Will I need to update my control systems with modification?

Quite possibly. It is something you should evaluate as part of the modification. For an equipment-only upgrade there may only need to be a slight modification or no change at all to your control systems. Mobile equipment options can include integral control panels so that they can truly be unpacked for fast, “plug and play” capability. For more complex modifications, control systems modifications may be necessary. Call Spiroflow to talk to a control systems engineer to evaluate your specific requirements. 

How can I ensure that my operational changes meet new worker, product safety and compliance standards?

Some production line modifications may be able to be made without the need for an on-site vendor visit. In this case equipment is ordered and shipped to your site, after which your crew assembles the project package.

In the event that installation, layout assistance or an installation inspection is needed on site, make sure to send your equipment vendor any COVID-19 specific safety protocols, requirements, restrictions or procedures before they arrive. 

For our own Spiroflow staff, we make sure to reach out in advance to understand your site’s specific safety requirements. Once we arrive on site, we follow your guidelines strictly. Communication on safety protocols prior to the site visit is the key for ensuring worker safety while vendors work to install and commission new equipment on site. 

How do I create the most value from equipment purchased for production modification after COVID events?

Ensuring that you purchase flexible, mobile equipment can mean getting the most out of your investment. When making equipment purchases for COVID-related modifications, look for equipment that can be reused to improve your existing operations when things return to normal. 

Don’t forget, any changes to products can be assessed in our test labs at our production facilities to get your modification right the first time. 

Stay tuned for Part 2 in our Making Manufacturing Shifts Series, Increase the capacity of your existing production line via equipment upgrades, coming soon! 

Which is better: aero mechanical conveyors or pneumatic conveyors?

Here at Spiroflow, we’ve been in the bulk material handling industry for more than 45 years. Given our experience, we find that aero mechanical conveyors are often a better option in many different types of processes. That being said, we’ve sold both types of conveyors over the years, and it’s important to first consult an engineer to understand if mechanical conveying (mechanical part moves material) or pneumatic conveying (air/gas moves material) is the best way to move your material. To help you understand the benefits of aero mechanical conveyors, we’re putting them up against pneumatic conveyors in today’s showdown.

Mechanical vs. Pneumatic: 6 Round Showdown

It’s time to settle the score. But first, some definitions.

What is an Aero Mechanical Conveyor?

An aero mechanical conveyor, or AMC, is a tubular conveyor that utilizes a cable and disc assembly. The movement of the conveyor is so rapid it aerates the product. As a general rule, each pocket contains about 80% air and 20% material.

It is one of the most efficient methods of conveying materials. Its dust-free and clean handling properties make the conveyor a good fit for many applications across several industries.

What is a Pneumatic Conveyor?

A pneumatic conveyor conveys material in a suspended stream of gas, usually air. When particulate materials are metered into an airstream, at an optimal solids-to-air ratio, the differential air pressure generated via a vacuum pump creates a high enough velocity to move the materials within the conveying tube.

Pneumatic conveying is a simple option to move material across challenging routes. The product is moved hygienically and is a good fit for several applications.

6 Rounds: Differences Between
Aero Mechanical Conveyors and Pneumatic Conveyors

Now, I’ll evaluate several characteristics that are important in considering the right conveyor for your dry bulk material handling needs. I’ll start with energy consumption, noise levels and venting.

Round 1 -Which conveyor is more energy efficient?

Is limiting power consumption a priority? Aero mechanical conveyors can convey material at a rate from 9 ft³/min (11.8 m³/hr) to 36 ft³/min (51.9 m³/hr) depending on the diameter of the tube. These conveyors can pull this off by using a drive motor between 2-7.5 hp through a gearbox. Pneumatic conveyors require a 20-40 hp blower to reach comparable rates to an AMC.

Round 2 – Which conveyor is quieter to run?

Is noise a factor? Aero mechanical conveyors operate below 85 dBA. Pneumatic conveyors are much louder than AMCs. They must be remotely installed or have mufflers installed, adding to the cost of the system.

Round 3 – Which conveyor has a better venting system?

One of the major advantages of an aero mechanical conveyor is that it’s a balanced system. Ambient air is drawn into the conveyor along with the material and the material is discharged at the outlet of the conveyor. The displaced air is drawn back into the conveyor creating the balanced system. There are no special venting or filtering requirements because there is no pressurization at the discharge point.

Pneumatic systems handle venting differently. A receiver is utilized that requires venting off the motive air. Compressed air is also required for backwashing the filters and valves required for proper operation. Pressure systems require venting with filtration for the receiving vessel with exhaust entering into the surrounding area or vented outside the building.

Vacuum systems generally draw motive air from the surrounding area. It is important to determine if special air conditioning or additional climate control will be required in these areas. This could greatly increase the cost of heating or air conditioning and should be factored into your budget.

That’s 3 rounds for AMC.
Let’s continue our showdown.

Round 4 – Which conveyor is best for layout optimization?

Multiple inlets and outlets can easily be integrated with aero mechanical conveyors. When multiple outlets are used we recommend that the conveyor operates at half speed. This ensures that the material exits the conveyor properly. A tube valve at each outlet provides a smooth path for the ingredient to pass through.

Multiple outlets on vacuum conveyors require a separate receiver, its own pressurized air supply for filter cleaning as well as its own feed control valve and diverter valves. Additional piping is also needed to feed each individual usage point. Each receiving point requires venting of the motive air as well as filters, valves, diverters, and additional piping to direct product to each use point for pressure systems.

Round 5 – Which conveyor is best to prevent the separation of and maintain blends?

Aero mechanical conveyors are considered gentle conveyors. Pocket fill is typically 80% air and 20% material. The air stream carries the product around any corners in the system and mixtures are maintained throughout the conveying process.

Pneumatic conveyors use a similar air-to-material ratio. The entire length of the circuit is under the same pressure or vacuum. Because of centrifugal force, the product hits the walls of the tube hard. This can lead to degradation of the material and wear on the machine. Blends are more likely to separate while being conveyed over long distances.

Round 6 – Which conveyor is easiest to clean?

Aero mechanical conveyors will transfer virtually all of the material introduced into the conveyor. Air purging is an option to clear out any residual material. Another option is dry cleaning, running a material like salt inside of the conveyor. Wash gates and drains are included when the application requires the system to be wet washed. When wet washing the AMC creates an agitation effect, like a dishwasher, that completely washes the inside of the conveyor. The conveyor can run while empty to dry out.

Pneumatic conveyors are also easily cleaned. They can be dry cleaned using salt to scour the conveyor. For wet cleaning, a “pig” is pushed through the piping system using compressed air. Since both conveyors are easily cleaned, this round is a tie.

And the winner is…

While aero mechanical conveyors have considerable benefits across industries and processes, it’s difficult to say which conveyor will truly work best for your process without an engineer knowing more about your operation. Not all processes are the same. At Spiroflow, we have a team of engineers in the United States and the United Kingdom that can help you. Feel free to contact us if you have any more questions.

How Do You Convey a Difficult Product?

Properties of Difficult Product

Your product may seem like an easy material to convey but it could be explosive, corrosive, hygroscopic or abrasive and all of these factors will have a significant impact on how it is conveyed. Factors such as these may be a challenge when conveying your material.

Flow Characteristics: Is your material sluggish or free-flowing? How the material behaves when it has been conveyed or unloaded is a primary concern when we design your equipment. If your product is sluggish as it is conveyed or it bridges then additional flow aides may be necessary. When we do a materials test we can understand the particular flow characteristics of your product which will help us to recommend the best equipment for your process.

Abrasion: Is your material abrasive? If it is then understanding how abrasive it is will influence what material your conveyor will be made from. When designing your equipment we want to ensure it has a maximum lifespan which we will do by reducing contact points.

Temperature: Temperature can apply to a variety of things such as material temperature, temperature while conveying & the ambient temperature in your facility will all affect how your material behaves as it is processed. This will all have an impact on how the equipment is designed for your process.

Testing the Product

If your product is characterized as ‘difficult to handle’. If it is friable, sticky, hygroscopic or tends to cake or pack, this can be difficult to handle. – In cases where you have a difficult to handle product, lab tests are essential to help us understand how your product behaves. After lab tests, machine trials will give you a full understanding of the product as it is being conveyed to avoid any potential future issues.

At Spiroflow we test for the following:

• Blending & Mixing – Segregation of blends and mixes can be a problem in conveying so our testing will assess how or if your product will segregate. This will help affect which conveyor you ultimately choose.
• Rate of Flow – Powders can vary greatly in their flow characteristics; some powders will pack or cake whereas others tend to fluidize when moved. We help to determine the flow of your powder in our machine tests to help develop the design of the equipment and inform your purchasing choice.
• Particle properties – Bulk solid materials and powders can vary greatly in their particle composition and size, shape and density so understanding the characteristics of your product is a key component of equipment design and choice

View a full list of our product database to find out specific information about your product here: Product Database

The Aero-mechanical Conveyor

Principle of Operation

Our Aeroflow aero mechanical conveyors are of a tubular design in which a continuous wire rope assembly with accurately spaced polyurethane discs move at high speed. At each end of the conveyor, the rope assembly runs around specially designed sprockets, one of which drives the rope assembly and the other tensions it. The drive assembly can be located at either the inlet or outlet of the conveyor depending on its length or to suit plant requirements.

The action of the rope and disc assembly traveling at high speed sets up an airstream running at the same velocity. As the material is fed into the airstream it is fluidized and conveyed to the outlet where it is centrifugally ejected. High capacities are possible with low energy requirements and with minimal product degradation and separation. Because the aeromechanical conveyor is so successful at moving product it is one of the few effective methods of handling titanium dioxide – a notoriously difficult product to convey.

Do You Have More Questions?

Thanks for reading this article. Feel free to share it if it was helpful. Spiroflow has been in the bulk material handling industry for more than four decades. If you encounter a problem, we probably have a solution. Let us know how we can help you.

If you’d like to see more of what we can do, check out our full line of products. We also do control systems integration; click here for more information on that aspect of our business.

Materials Testing & Equipment Testing

Spiroflow welcomes customers from around the globe to conduct feasibility trials and equally importantly, to offer advice on the comparative advantages of different conveying and bulk bag handling methods relative to the customer’s application. We are fully equipped with flexible screw, aero mechanical and tubular drag conveyors, as well as bulk bag fillers and bulk bag unloaders and a bulk bag conditioner. We can advise without bias on the right type of solution for your particular product, application and layout restraints. Wherever possible, we simulate your site conditions in terms of conveyor length, flow rate and angle of lift.

We have full test equipment set up in both our US and Europe locations. Trials are set up to our customer’s requirements in terms of conveyor length, angle of elevation and output. With a wide variety of equipment, we can find the right equipment to suit your process.  We also have a database of product conveying trials logged over 45 years, taking the guesswork out of assessing flow rates and expected performance. Trials are also offered at customers’ premises where the product and/or application dictate this to be the best course of action.

Materials Testing

Using our lab we will test your product to see the angle of repose, flowability and bulk density, which will help us choose the best application for your product. Any powders (free-flowing and non-free flowing) chips, flakes, pellets, spheres, granules and more, we can help you move it! Read our blog: Materials Test: Do You Need One?

Book A Test

If you are interested in booking a materials test of a machine trial then fill in our Contact Us form and someone will be in touch to discuss your application.