Independent Equipment Validation Reveals Differences Between Sensor Data and Actual Production

Automating data validation ensures, verifies, and documents feeding accuracy for consistent product quality and compliance with regulations.

July 14, 2023

7 Min Read
The Feedos S weigh feeder from Gericke comes with automated independent feeder validation software.Image courtesy of Gericke USA

Rene Meira Medina, executive vice president, Gericke USA

During the great infant formula shortage that began in 2020 and largely continues today, the FDA demonstrated that when it comes to powder processing, even statistically tiny numbers can trigger huge, highly damaging effects.

Though a link between tainted infant formula and two saddening fatalities has not been formally documented, production at the plant implicated in the ongoing investigation remains shutdown as of this writing at the regulatory body's invitation. Meanwhile the global formula supply continues to fall short of demand. This situation isn't restricted to formula.

Consider the importance of measuring and feeding precise amounts of powdered, active pharmaceutical ingredients (API) in a specific ratio relative to the excipients. Underfeeding the API may reduce the efficacy of the pharmaceutical drug and fail to treat the patient, while overfeeding may injure or even kill the patient. When the consequences of seemingly minute variations in ingredient properties, recipes, measurements, cleanliness, and other process parameters during manufacture are potentially deadly at worst and massively costly at best, then paying extra attention to the tiny details becomes crucial.

A crucial detail that is often overlooked by manufacturers is the accuracy of the sensor data provided by their process equipment. The HMI may show a feeder metering six tons of milk powder per hour into a continuous process, for example, but how does an operator know if that readout is accurate? Since manual performance testing typically cannot provide the level of accuracy needed to measure minute but significant discrepancies, how can this be assessed without waiting until product quality becomes compromised?

Proper Calibration

The first step in ensuring that automated weigh feeders, mixers, and other process equipment are properly measuring and recording process data within required tolerances is with calibration. This process is typically performed in-house by an operator who compares the readings of the equipment against accepted reference standards. Process equipment typically arrives from the manufacturer as certified to within factory specifications but after initial setup, periodic calibration needs to be performed to ensure the instrumentation remains within required tolerances.

Unfortunately, the calibration may be disrupted during ordinary operation without any outward sign to alert the operator. Changes in the material properties upstream, for example, such as in the particle size distribution, bulk density, or flowability can lead to deviations in the feeding rate and/or to inconsistent dosing as the feeder struggles to accommodate the new material. Or normal wear on the feeder screws, seals, or other components may cause drift that increases or decreases the flow rate through the feeder and causes more or less material to feed than intended. Either case would signal a need for recalibration, if recognized. Disassembling the feeder for cleaning and reassembling it, along with any other type of maintenance or repair, typically requires recalibration before returning the line to service. Even electrical malfunctions, plant vibrations, or improper equipment usage can require recalibration. How often calibration is performed as a routine quality check is ultimately determined by the operations team based on the actual performance of the process equipment and whether the quality of the end product consistently meets targeted specifications.

But the calibration process can challenge even experienced maintenance staffers. The process is inherently prone to human error and proper training on the necessary procedures for each type of equipment is essential. Otherwise, a newly calibrated machine may be returned to production and yield inaccurate data that is believed to be highly accurate. Decision-making based on this data is destined to fail from the outset. Insufficient documentation, direction, and record-keeping also lead to shortcomings in the calibration process. The end result, whether by a faulty calibration process, normal equipment operation and wear over time, or by the unintended consequences of changing material properties or environmental conditions, is a discrepancy between the required feed rate and the actual feed rate.

Independent Validation

Since this discrepancy between the feed rate shown on the controls and the actual feed rate in operation commonly occurs at some point in nearly every bulk solids process worldwide,  independent validation is recommended. Whether by an outside, third party, or by automation technology, the independent validation process aims to reveal, quantify, and document this discrepancy before it can adversely affect product quality. Or it can aid in restoring product quality after the fact. Once any deviations are uncovered, operators may then diagnose and identify the cause. Appropriate adjustments may then be made to the ingredient properties, to the storage and transfer process upstream, to environmental conditions such as humidity or temperature, or to machinery maintenance and repair, as appropriate. Process instrumentation settings may be fine-tuned and recalibrated based on any adjustments made to the process. This ensures the process is optimized, improves overall efficiency, and promotes consistent product quality with increased throughput at a reduced cost structure.

Proof is in the Outputting

As if producing on-spec product faster at a reduced cost structure is not reason enough to consider independent validation, consider that independent validation also provides the comprehensive documentation required to comply with FDA, USDA, and OSHA regulations, ISO certifications, and other industry standards, directives, and regulatory requirements. The FDA emphasizes the importance of equipment validation, verification, and control to promote food safety. The USDA may require independent validation within the Hazard Analysis and Critical Control Points (HACCP) system for addressing food production hazards. The validation process offers legally accepted verification that the weigh feeders and other equipment function correctly and meet the targeted quality specifications while providing a high level of data integrity, transparency, and traceability. In the event of an audit or inspection, providing access to independently validated data instills confidence in the integrity of the operation and speeds an investigation process to aid in avoiding a recall or plant shutdown.

Internally, this verified data protects plant personnel from shouldering responsibility for errors or quality issues that arise downstream. As an aid in risk management, independent validation helps uncover, identify, and mitigate potential risks before they reveal themselves as product quality failings, contamination, explosions, or health and safety issues. This proactive approach helps protect the end consumer as well as the reputation of the manufacturer. In the event of a situation, the documentation provides a clear, historical record verifying equipment specifications, testing methodology and results, and any staff involved at any given time, for smooth traceability and fast identification of root causes, diagnoses, and appropriate solutions.

Automated Independent Validation

While many gravimetric loss-in-weight and volumetric feeders and other types of process equipment currently in operation provide a basic degree of data acquisition, analysis, and documentation, the latest generation of feeders includes new technology that automatically monitors the process in real-time. This approach constantly provides highly accurate data to allow real-time analysis and automated adjustments. Changes in the bulk density, particle size, motor speed, flow rate, refill time, or other parameters are instantly detected to permit fast response as needed and ensure the feed rate is optimized.

Feeder Software

In continuous mixing and other continuous processes, this feeding technology promotes the precision metering that ordinary screw feeders and rotary valves cannot offer to ensure the desired ratios of major, minor, and micro-ingredients is maintained automatically, 24/7. When changing the recipe, product, or formulation, this type of control software provides the independent validation needed to feel confident that moving ahead with a large-scale production run will result in a high volume of on-spec product. These feeder control systems also seamlessly integrate with enterprise resource planning (ERP) automation software, manufacturing execution system (MES) process control software, programmable logic controllers (PLC), and Internet of Things (IoT) networks to simplify the upgrade process. For remote workers, the advanced controls may be securely accessed and adjusted on-the-fly using a phone.

As food, pharmaceutical, nutrition, and other manufacturers pay closer attention to seemingly tiny details in hopes of uncovering far-reaching opportunities for cost savings and process improvements, many are finding automated independent equipment validation worth investigating. Integrating this advanced level of automation provides an additional layer of confidence in the data acquired by the weigh feeder or other process equipment and may result in quantifiable improvements in throughput, quality, and safety, along with the documentation required to demonstrate regulatory compliance.

Rene Meira Medina is executive vice president of Gericke USA (Somerset, NJ). Founded in 1894, the company designs and manufactures a range of feeders, mixers, lump breakers, pneumatic conveying systems, and other powder processing equipment. For more information, email [email protected], call 855 888-0088, or visit

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