Fluid Air Blog

Welcome to the Fluid Air Blog! This page is updated on a regular basis with tips, guides, and other information on solid dosage processing. The introduction paragraph of each post is displayed under the post's image and headline, along with links to view/save a PDF or view the original post as it appeared on fluidair.blog.com.

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5 Important Maintenance Areas to Increase Equipment Reliability

Fluid Bed Filter
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Within the world of Oral Solid Dosage, the medications that command the highest premium tend to be the most difficult to process with predictably rare ingredients. These products often require the use of high-shear granulators, mills and Wurster coating fluid beds. These machines are workhorses, often running for decades while requiring only minimal maintenance. When they do fail, however, the result can be the rejection of not just one, but several very high value batches. To help you prevent such failures, here are the five most common areas that can be easily prevented through proper inspection.

System Filters

All outside air is considered to be dirty for the purposes of fluid bed processing. All fluid beds have at least an inlet HEPA filter. On a lab scale fluid bed, this may be just a drum filter inside the machine. On a pilot or production scale unit, this would be the last of a series of pleated filters in an air handling unit. Regardless of size and style, these filters should be inspected on a monthly basis for machines that are being run regularly. Inspection of these filters could prevent catastrophic failure, like the possibility of releasing contaminants into the process, without warning to the operators.

The next filter in the system is the bowl filter plate. The filter plate allows the air to flow into the product bowl while minimizing the transfer of product into the plenum. Regardless of the style of filter plate, some product will always sift through it. It’s important to carefully inspect the filter plate every time it is washed to ensure no product is captured within the screen, to prevent possible cross contamination.

The chamber filter bags and cartridge filters are the most abused portion of any fluid bed system. They are wetted, heated, dried, shrunk, stretched, scraped and tumbled in washing machines. It is failures in these bags that lead to the highest percentage of product yield loss. As filter bags become blinded by product, the increased vacuum places huge stresses on the seams. It is important for the seams to be carefully inspected every time the bags are washed to ensure that there are no seam failures. Filter cartridges, while less likely to catastrophically fail, are more likely to be damaged in cleaning. They have a PTFE coating to reduce product adherence, but that coating is easily scraped away. Always gently used compressed air to blow product out from the inside of the filter and use low pressure water to rinse the surface. To ensure systems continue to run efficiently please order filter bags and cartridges well in advance, we recommend having a few spares on hand as lead times are often a few weeks. When ordering, remember to ask if filter bags are made 100% with FDA product, contact approved and lot traceable materials - Fluid Air filter bags always are.

Outlet HEPA filters are designed to prevent the dust that inevitably migrates past the chamber filters from getting into the atmosphere. Outside the building, this could be an EPA issue. Inside the building, it could be a workplace safety issue. The outlet HEPAs should be inspected with the same care and frequency as the inlet HEPA filters.

Gaskets and Seals

Over time, all gaskets and seals will become dry, crack and crumble. The seals with the most likely impact on product are the agitator seal in a fluid bed dryer and the impeller and chopper seals in a high-shear granulator; all three of these locations are extremely high wear, product contact areas. The operators often inspect the agitator and impeller seals as a part of their cleaning process, but they rarely remove the chopper to clean behind it and inspect the seal. This area may retain old product which may create a cross-contamination risk and rapidly abrade the shaft seal. The failed seal, hidden behind the chopper, may not be noticed for several product batches. It’s imperative that the chopper be removed every time the machine is cleaned.

The next most common failures are gaskets on the high shear granulator lid, the fluid bed chamber and bowl, and the fluid bed plenum inlet seal. These items should be visually inspected by the operators every time the equipment is used.

Just like filter bags, gaskets and seals should be ordered and spares should be in house to prevent integral machines being down for maintenance.

Hydraulic Oil

High-shear granulators, fluid beds, and tote lifts use hydraulic power for their operation. Although the hydraulic power packs are out of sight, it is vital that they be part of any planned maintenance schedule. Maintenance personnel should observe the hydraulic power packs while the equipment is being operated. The oil in the units should be tan/brown. The temperature should stay below 140° F and the oil level should be unchanged. If the oil level is low, there is likely a leak which must be located and fixed. When adding oil to a system, cleanliness is paramount. New oil, in sealed five gallon buckets does not meet the cleanliness requirements. It should be pumped through a filter and into the reservoir tank. We suggest changing the system filter once per year and inspecting the oil every six months.


Nozzles are often disassembled for cleaning and tossed into plastic bins, without regard for their extremely sensitive nature. Air atomizing nozzle spray setups consist of two main components: the air cap and the fluid cap. In both components, the sharp machined edges of the liquid orifice and the air annulus grab the liquid droplets, shear and spread them to form the spray pattern. Scratches caused by mishandling will create additional sharp edges and grab more liquid causing the spray pattern to become inconsistent. This is especially important in Wurster coating because some product will receive a heavy coating and may begin to agglomerate while other product receives only partial coating. Nozzles must be treated with the same care as any calibrated lab equipment. Operators should be trained to carefully inspect nozzle setups during assembly. Setups that are damaged should be replaced.


Pneumatic and hydraulic cylinders are used in fluid beds, high-shear granulators and tote lifts. The less cylinders are used, the more maintenance attention they require. If equipment is sitting unused, the film of oil on a cylinder can dry damaging the cylinder seals as they are dragged over the dry metal surface. It is important that if equipment is idle, maintenance is scheduled to stroke the cylinders as often as once a month. The filter lift cylinder in a fluid bed has an extremely long stroke and is often left in the extended position for long periods of time. When in operation, it is expected to hold the filter bag up without drifting. If it drifts, it could cause impact on the product, damage top spray granulation arms, or, in extreme cases, become a safety issue for operators. We recommend that the holding capability of filter bag cylinders be checked during 6 month planned maintenance intervals.

Here at Fluid Air, we have an extensive amount of experience in solid dosage processing equipment. Our Field Engineering team consists of engineers who are experts in all areas of the equipment. Our Field Engineering team is available to provide on-site equipment operation, maintenance and process training tailored for your facility. They are also available to perform planned maintenance inspections of your equipment providing the highest level of care for your equipment while freeing your maintenance staff to focus on the day to day tasks required to keep your operation running smoothly. Regardless of your needs, Fluid Air can partner with you to fulfill them.

Written by David Rose, Field Engineer

To inquire about bringing one of our Field Engineers in to assist your team, email fluidainfo@spray.com. Close ▲

The New & Improved GRANUMILL® 007

tablet coating
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Achieve optimal efficiency with the new and improved Granumill® 007. We have redesigned our impact and screening mill to maximize usability and increase performance. Fluid Air understands your unique situation and will build custom machine configurations specific to your needs and existing equipment.

Reduce Maintenance

Re-designed Rotor housing

GRANUMILL® 007 features a new rotor housing design that can be easily and entirely disassembled without tools, allowing for a more thorough cleaning. The housing assembly is the chamber in which the milling action takes place. It is held into place with quick-release clamps for efficient disassembly.

Sleek, fin-free motor

The motor casing now features smooth, polished stainless steel with no cooling fins on the casing sidewall for more efficient cleaning.

Enhance Safety

Locking Mill House

Once the mill is operating, the locking pins and dual safety switches will prevent operators from opening the rotor housing until the machine has stopped rotating and is in a safe condition. Pneumatic safety circuit prevents the mill from starting without the cover in place.

Explosion-proof construction*

The mill control panel is stainless steel, NEMA 4, with a gasketed door for increased safety. The system will contain a purging system, a variable frequency drive, and a Power On/Emergency Stop switch.


Increase efficiency

Rotor and Screen Options

Interchangable rotors and screens are available for milling a wide variety of products and consistencies to process wet and dry materials.

Machine Change-Over

Interchangable rotors and screens are available for milling a wide variety of products and consistencies to process wet and dry materials.

For further information on GRANUMILL® Size Reduction Mills, click here. Close ▲

The Best in High-Shear Granulators

tablet coating
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A high-shear granulator or high-shear mixer uses a rotating impeller or high-speed rotor (or both) to create flow and shear. High-shear granulation is an effective way to turn powders into dense granules for tableting or coating. To create the granules, powders are added to the mixing bowl and the bowl is sealed. A large impeller rotates at slow speeds, spinning the powders into a vortex. After the powders are blended together, liquid is added to the product using a pump or pressurized container. A high-speed chopper tool located in the bowl shears the granules and removes air. The mixing continues until the desired granule size and density are achieved. Mixing processes vary from each application so when searching for a mixer, here are some key features to look for that can optimize your process and maximize your batch.

1. Look for flexible bowl configurations

Look for bowl geometry that greatly impacts the efficiency and permits working volumes from 30 – 90% of full capacity - many models max out at 66 – 75%. The design of the impeller and chopper is critical to creating an even mix. The impeller lifts the product directly into the line of the chopper. This, combined with the binder, creates the desired granule size and density.

2. Mixers that are equipped with auto-cleaning and liftable tool systems

Mixers that are equipped with auto-cleaning (WIP) and liftable tool features, save much time in cleaning while reducing set- up time, most important it reduces downtime between batches. The liftable tool system raises the impeller 4-8” to permit inspection or swabbing of the impeller bottom, seal and bowl bottom.

3. Check to see where the impeller and chopper are located

The proper design of the impeller and chopper are essential in the mixing efficiency and where they are located. The best performance is if the impeller is bottom-driven and a side-mounted chopper, this will eliminate dead spots, and ensures the material is uniform in this configuration. Having a consistent impeller tip speed, ensures scale-up from R&D through production.

4. Elliptical or dome shaped lids

Elliptical or dome shaped lids permits product to perform a complete roll over, ensuring a homogeneous mix in a variety of formulations, minimal clean-up and aids the batch yield even when running at larger operating capacities.

5. End point accuracy

The ultimate goal of any measurement in a granulation process is to estimate the density of the granules, and, perhaps, to obtain an indication of the particle size mean and distribution. These variables provide information for end point determination, reproducibility and scale-up. End point accuracy is achieved by a variety of methods; torque, power consumption and amps.

6. Effortless loading and unloading

A variety of loading and unloading systems can be designed, for better material handling. The multi-stage seal purging system permits operating at low and high seal flows. This helps prevent dusting when loading and allows setting of the flow to match product characteristics.

7. A hydraulic drive system

For larger-scale mixers, a hydraulic drive system permitting full torque down to ¼ RPM providing plenty of break-out torque at slow speeds for additional mixing after inspection and continuous discharging to wet milling systems.

For further information on High Shear Granulators, click here. Close ▲

Easily Eliminate 3 Common Tablet Coating Problems

tablet coating
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One of the final stages of producing any pharmaceutical or nutraceutical tablet, coating is the essential process that seals a raw tablet, often in order to protect the active ingredients in the drug, protect the stomach lining of the patient, or provide a delayed/time-sensitive release of the medication. In order to achieve these results, the coating process must run smoothly and evenly. Avoiding issues isn’t always an option, but eliminating them when they arise is possible. Here are a few troubleshooting tips to resolve three common tablet coating problems.

Problem 1: Clogging/Bearding

Solution A:

If the clogging is occurring at the nozzle tip, it is likely a result of the coating solution building up around the nozzle over time, commonly referred to as bearding. Look for spray nozzle tips specially designed to reduce bearding.

Solution B:

If the clogging is occurring elsewhere in the system, consider if your process could benefit from an automated fluid delivery system. Some advantages of automated fluid delivery systems include:

  • Precise, low-pulsation peristaltic pumps eliminate “dead-leg” liquid distribution
  • Nozzle liquid feed pressure sensors detect clogging
  • Nozzle clearing circuit, line clearing and purge system

Problem 2: Suspended solutions settling/clogged liquid lines.

Solution A: Re-circulating spray nozzles

In ordinary liquid-delivery systems, when the shut-off needle is extended, the solids in the coating solution can drop out of suspension, leading to uneven coating or nozzle clogging. In addition, temperature-sensitive solutions can harden or stagnate in a nozzle, causing blockages. Recirculating the solution inside the spray nozzle/liquid delivery system eliminates these issues, allowing the shut-off/clean-out needles to be extended for cleaning/inspection of the nozzle or to suspend the coating process.

Solution B: Re-circulating spray manifold

For larger spray systems, an integrated manifold could be one possibility. A connection hub eliminates the need for multiple connections to each nozzle, greatly simplifying setup time. Because the spray nozzles' liquid recirculation return is housed inside the nozzle body and ported through the manifold, fewer liquid lines/connections are required; this reduces the number of tubes that ultimately go inside the coating pan, reducing cleaning/changeover time.

Problem 3: Inconsistent coating thickness, inconsistent spray

Solution A: Process controls/monitoring.

Achieving a consistent coating thickness within tight tolerances can be very difficult, especially with larger operations. A fluid delivery system with integrated process control software can provide precise control and monitoring over your entire process and provide real-time data for critical factors such as nozzle performance and liquid flow rate.

Solution B: Complete integration of spray and fluid delivery system with process controls.

For those with delicate, experimental or research-oriented applications, an integrated system that includes spray nozzles, nozzle connections, fluid delivery and process controls may be the solution. Working with your existing coater, these systems allow users a level of precision, monitoring, and data logging capability that can help to allievate many of the headaches of the tablet coating process, streamlining your batch operation at a fraction of the cost of a new or upgraded tablet coater.

For further information on Tablet Coating Systems, click here. Close ▲

How to Decide: Which Mill System Should I Buy?

granumill jr
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With the large variety of milling equipment on the market, it can be difficult to know which type of mill is appropriate for your process. The basic mechanical process of milling, also known as grinding, granulating, comminuting, etc., is generally used either:

  • A) to break apart clumps or agglomerates– that may have developed during storage, transportation, or handling of a given material without altering the average/mean size of the particles which make up the material, a process often referred to as deagglomeration;
  • B) to reduce the average/mean size of the particles in a given material, also known as particle size reduction.

Because of the relatively simple nature of these two processes, as well as the range of industries in which they are employed, milling machines can differ dramatically in terms of their fundamental principles of operation; this is especially true of size reduction machines. Jet mills, impact mills, screening mills, cone mills, ball mills and hammer mills are just a few of the different operational classes of mills available, and if you’re unfamiliar with the terminology involved, this can be especially confusing. Here are a few things to look for to help you determine which mill might be best for your application.

1. Versatility.

If you’re looking to purchase a new mill, chances are good that you already know exactly which types of material you’re going to be processing with it. However, given the high cost of pharmaceutical-grade equipment, even mills, it is imperative to consider the future potential of any new piece of equipment. What projects might you take on in the next 5-10 years? If you plan to use the mill for a new R&D application, will you still have a use for it in the future, after the R&D stage is complete? Will you require particle sizing as well as deagglomeration capabilities?

Certain systems, like Fluid Air’s GRANUMILL® Jr., are classified under the FDA’s SUPAC (Scale-Up and Post-Approval Changes) guidelines as both a hammer-class mill (Fitzmill®) and a screening mill (Quadro Comil®). This means that the machine is suitable for both high-speed fine grinding for size reduction as well as low-speed screening for simple deagglomeration. Whatever your current requirements are, be sure to look for a system that won’t limit you to any one project, if possible.

2. Scale-up.

If you’re purchasing a unit for an R&D application, do you plan to scale up your current process? Certain rotor speeds, tip speeds, blade types and other parameters that are effective for small-scale processing may not be feasible at a pilot or small production scale. Check to see if these parameters are scalable for larger batch sizes. If you already own a large-scale mill system and are looking for an R&D unit, determine whether the specifications of the smaller system will be readily scalable to meet your existing system. Even if you do not anticipate the need to scale-up now, it is worth investigating beforehand instead of scrambling to find a solution later.

3. Safety/exposure needs.

Make sure that the equipment is able to meet any occupational exposure limits to ensure safe levels of operator exposure, even if you do not intend to process hazardous materials/APIs. Some manufacturers offer optional containment enclosures that can be removed when they are not in use. For explosion-critical applications, nitrogen gas purging and cryogenic milling with liquid nitrogen injection systems are two other options to look for.

Those processing volatile compounds should ensure that any new unit is equipped with the appropriate safety mechanisms and constructed to prevent, withstand, or mitigate any potential explosions that may occur.

4. Sanitation/cleaning requirements.

Is the system compliant with your cleaning requirements? Many machines, especially R&D systems with small parts, can be difficult or impossible to adequately clean. Milling systems equipped with quick-release housing clamps are ideal for applications where sanitation is critical, as they allow the entire system to be broken down and submerged in a cleaning tank, greatly simplifying the cleaning process and reducing maintenance time. Aseptic processing using liquid nitrogen is another option for applications where sterility is critical. At a minimum, check that all of the system’s product-contact surfaces can be readily accessed and inspected to ensure thorough cleanliness.

For further information on Size Reduction Mills, click here. Close ▲

Five Things to Consider Before Purchasing Used
Solid Dosage Processing Equipment

solid dosage processing equipment
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Pharmaceutical companies sometimes choose to buy equipment second-hand, either from another pharmaceutical company or directly from the manufacturer of the equipment. While there exists a large and diverse market for used equipment, there are many things to consider before purchasing any used or refurbished system for processing pharmaceuticals. For example, while refurbished systems are often available at substantially lower prices than new ones, there may be undetected defects which will require repair. Additional overhead and maintenance requirements to get a refurbished machine running– like software upgrades, tracking down replacement components, system installation, integration with your existing process, possible re-validation procedures, etc.– can greatly increase the system’s total cost. Those who work for small R&D companies and start-ups often have trouble securing the necessary funding for a brand new machine. Large purchases leave small companies with little room for error, but with the current glut of systems in the used equipment market, how can you tell which will ultimately be worth the investment? Here are five questions to ask which should help determine which system will be right for you.

1. Is the system equipped with the required hardware/software?

Be sure to check the condition of the system’s control software- it may be outdated, or unsupported by its original manufacturers. Depending on the system, software replacement can be more expensive than buying a new machine. Verify the software has the features you need for your process; does it meet your requirements for data collection, automated batch control, security, etc.?

2. How has the system been used?

Determining what a system has been used for is, in most cases, the best place to start when deciding whether or not it suits your needs. If it has been used to process proprietary materials, the owners probably won’t be willing to discuss specific operational parameters. However, they may be able to tell you the kind of research the unit was involved with, the general type of processing it was used for, or even the trade/generic name of the specific drug(s) it has produced.

To avoid potential problems with the FDA, create a secondary-source document (if adequate primary documentation is unavailable) cataloging all the data for each compound that the machine has processed. If this information cannot be found, contact the original manufacturer and check whether they are willing to disclose any information they may have on the system’s usage.

3. What functions do I need the system to perform?

Make sure that the equipment you’re looking at can actually do what you need it to. If you aren’t able to determine the unit’s exact specifications, the system’s manufacturer or the owner/operator should be able to provide more details. If the system doesn’t exactly meet your needs, can it be upgraded? Can other options be added to increase the functionality of the system? These are questions that the manufacturer will be able to answer. Examples of common upgrades include humidification systems, modern filter systems, solvent-recovery systems, materials handling capabilities and replacement spray nozzles.

Some systems can be converted, but at significant cost. For example, a basic fluid bed dryer can be converted into a top-spray granulator or Wurster coater. In these cases, it is best to look for a different machine that is already capable of performing the functions you require.

4. Can the seller provide original documentation?

If they cannot provide the original documents and operating procedures, can they provide a backup reference? Can they provide training or detailed instructions on proper operation?

Verify that the original manufacturer hasn’t issued defects or end-of-support notices on the equipment or the control system. Determine whether you can purchase spare or replacement parts from the manufacturer, even if you don’t need them at the time of purchase.

5. Is this worth it?

Before making any purchases, have the equipment inspected by a trusted specialist who is familiar with your requirements. Request a quote or an estimate for additional modifications or expenses that may be necessary. It is very likely that the machine will need to be upgraded, redesigned or completely customized depending on validation requirements and drug processes.

Weigh all of your options carefully before making a decision. If the used equipment needs a lot of work, it may be more trouble than it’s worth, or there may be new systems available for a similar price.

For further information on Fluid Bed Systems, click here. Close ▲

Five Tips for Finding the Right Fluid Bed System

fluid bed system

Purchasing a new fluid bed system isn’t easy. Fluidized beds are expensive, complex, and require a great deal of careful consideration and research before buying. Ordering a machine that can’t meet your process requirements could end up costing much more than anticipated, and there’s no single system available that will suit everyone’s needs. So, where should you start?

1. Determine your short-term and long-term processing goals.

What are you looking to get out of a new system? There are a lot of options available, but knowing exactly what you want is sure to narrow the field a bit. Take the time to figure out which functions and features are absolutely necessary for your process right now, and go from there. Considering the costs involved, it’s highly likely that it may be many years before your company can once again justify the cost of a new system. Bear in mind that the goals for your present business or research may change unexpectedly in the future. Decide what your long-term goals are, and invest accordingly.

2. Decide if a new system is right for you.

Although the idea of a shiny new system can be appealing, in many cases, it may not be necessary. Those considering the purchase of a new machine to replace an older fluid bed system should not overlook the range of cost-effective alternatives that are available. Retrofitting an existing system to add new functionality, replacing worn components or upgrading outdated technology may be all that is required to make an old machine feel brand new.

3. Choose versatile systems capable of accommodating multiple applications.

Some fluid bed systems offer multiple functions– like fluid bed drying, granulating and Wurster coating– in a single system. Even if you don’t require the extra functionality right now, in the long run, this will save you from spending considerable money on the purchase of a second or third machine to perform additional applications.

4. Look for special features designed to speed up your process.

Conical expansion chambers

The conical shape can cut the velocity of the air in the filter chamber by up to 50%. This keeps fine particles suspended below the spray nozzles, reducing the time necessary for fluid bed granulation.

Agitator systems

Located in the bottom of the bowl, agitator systems rotate through the material in bowl bed to eliminate “dead spots” and ensure proper fluidization. This saves the operator from having to shut down the process and manually shovel or rake the bottom of the bowl bed.

Liquid-delivery manifolds

Round “chandelier” liquid-delivery manifolds, mounted above the bowl, allow granulation to be adjusted without interrupting the process. Carefully positioned to ensure uniform distribution of the binder solution, the manifold’s top-spray granulation nozzles point down toward the bed surface, allowing users to deliver a greater volume of solution per minute without fears of over-wetting certain areas due to overlapping of the spray.

5. Work with experts to be sure that your machine is the right one for your requirements.

Few manufacturers have the capability to expand upon their standard “off-the-shelf” product lines, which are often designed to perform only the most common types of processing applications. For customers with very specialized applications or unusual requirements, this can make it very difficult to find the right machine. Look for suppliers who are willing to modify, redesign or completely customize their systems to meet your needs.

For further information on Fluid Bed Systems, click here. Close ▲

Know Your Software: Reduce the Risk of an
Unexpected Controls Malfunction

process control software

With the ubiquity of personal computers and mobile devices like smartphones and tablets at an all-time high, nearly everyone has become well-acquainted with the experience of computer glitches. These glitches can range from minor annoyances — like a window closing when you didn’t want it to — to serious problems, such as a program crashing without saving its data or a complete system shutdown. While these issues can be frustrating when they happen on a personal computer, the consequences of a potential controls malfunction when it comes to your pharmaceutical processing application can be far greater.

The costs of process downtime or lost batches as a result of a controls failure can be enormous. Given this, it seems as though repairing aging or obsolete software would be well worth the costs involved– especially when weighed against the risks of operating malfunctioning controls. Even so, software updates can be difficult to justify. For users unfamiliar with computer programming languages, process controls may seem like a virtual “black box;” because they cannot access or otherwise understand the complex code that constitutes a given piece of software, they cannot determine where the problems are occurring and where changes will be made– or if they are even necessary. This makes it complicated to assess which modifications will ultimately be worth the effort and cost of re-validation.

We understand that equipment, applications, controls and process requirements can differ greatly from one user to the next. Depending upon the status of your system’s controls, making modifications to the software can be very costly, and potentially not worth the expense. Our solution is to provide users with risk assessment documentation to evaluate the risks of modification based on the proposed or desired changes to the control software.

Risk assessment is a cost-effective way to determine the best course of action to satisfy your specific software/control requirements. Before making any changes to your software’s code, we first analyze it and generate a risk matrix to identify any potential errors or bugs and evaluate the objective risk. Customers can then use the risk matrix to assess whether or not the risk of repairing any potential problems is greater than the risk of continuing to run the software with them in place.

The risk matrix will also determine:

1. The severity of the bug’s impact.

Will it cause a window to close, or will it cause the entire system to fail? If the bug’s impact is negligible, modifications to the software may not be worthwhile.

2. The probability of the bug’s occurrence.

What are the chances that users will experience the bug? If a user never uses a particular feature that causes the bug to occur, no modifications may be necessary.

3. The probability of the bug’s detection.

Are users likely to notice the bug? If a bug causes a window to close, users are likely to detect it; however, if a bug causes a value to calculate incorrectly, users may not notice it at first.

For further information on Process Control Software, click here. Close ▲

Two Common Wurster Coating Challenges- Resolved!

Wurster Coating
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Wurster coating can be tricky, even in small-scale R&D batches. Larger-scale batches must be monitored carefully, as any mistake could result in costly product waste. Production size Wurster coaters with multiple coating partitions have two very critical process challenges to overcome: balancing the air flow to each coating zone, and the potential for clogged spray nozzles.

Process air entering the system’s inlet plenum below the multi-partition coating bowl will naturally seek the route of least resistance in moving up through the screens, product in the bowl, and out the exhaust. Some partitions will see an abundance of process air while others will be starved unless corrective measures are taken.

An air-starved partition will quickly fill with particles from the active partitions. The product will come in direct contact with the nozzle, resulting in over-wet product and potentially the loss of an entire batch. We’ve overcome the potential for poor air distribution by inserting a special plate assembly with adjustable shutters beneath each coating zone.

This allows the user to adjust the air flow to each zone and lock down the shutter once proper equalization has been achieved and before any coating activity commences. Balancing occurs during set-up and can be repeated for the same product as part of a batch record set-up.

Our fluid bed systems can also be outfitted with optional self-clearing spray nozzles. Self-clearing spray nozzles are equipped with a pin in the nozzle tip which fires when high liquid pressure is detected, clearing the nozzle of debris. Self-clearing nozzles are ideal for solutions that have solids which can accumulate in the nozzle tip.

For further information on Wurster Coating and other advanced fluid bed technologies, click here. Close ▲

Four Ways to Update Your Fluid Bed System
(Without Replacing It!)

Retrofit without replacing
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Everyone wants their equipment to look, feel, and run like it did when it was brand new, but years of operation and wear can take their toll on a system’s effectiveness. Constant advancements in processing technology and new federal regulations combined with everyday wear-and-tear can really make your formerly “state-of-the-art” piece of equipment feel like an antique– but purchasing a new system is expensive, and not always practical. Here are just a few of the ways that Fluid Air can revitalize your existing equipment, often at a fraction of the cost of a new machine.

1. Add new functionality.

Add new optional features, like humidification, solvent recovery, filtration and material handling systems to simplify your process and increase efficiency.

2. Equipment conversion.

Fluid Air can convert your fluid bed dryer into a fluid bed dryer/granulator or Wurster coater, turning your machine into a multi-purpose processor and eliminating the need for a second system!

3. Upgrade your process control software.

Upgrading to the newest version of our recipe-driven Batch Architect™ process control software is a popular option. Batch Architect is compatible with all batch-type equipment including fluid beds, mixers, tablet coating pans, pellet-making process trains and liquid delivery systems. Batch Architect is easy-to-use and available in basic and professional (21 CFR Part 11 capable) versions.

4. Replace your spray nozzles.

Even the best spray nozzles need to replaced after they start to wear from repeated use. Spraying Systems Co.® offers a full line of nozzles that are ideal for fluid bed coating, granulation, and spray drying applications.

For further information on Services & Upgrades, click here. Close ▲