Condition Monitoring - Food and Beverage Industry

Index

• Condition Monitoring in the Food and Beverage Industry
• Thermography for Quality Assurance And Product Safety
• Solutions for the Food and Beverage Industry
• Equipment Monitoring
• Packaging Inspections
• Automating Measurements
• Related Products

In the food industry, precise temperature control of perishable goods is paramount across production, transportation, storage, and sales stages. Concerns over foodborne illnesses underscore the importance of stringent process control. Given the inherent human element, food processors require tools that automate critical operations to reduce human error and minimize costs. Additionally, non-contact inspection tools are essential for conducting routine predictive maintenance surveys on equipment throughout the manufacturing process. This proactive approach enables the early detection of faults, allowing for timely repairs and preventing unplanned downtime, thereby ensuring consistent production.

Thermal imaging cameras provide valuable insights into the manufacturing process. Whether employing handheld or fixed thermal cameras to monitor equipment and anticipate maintenance needs, or utilizing fixed cameras to ensure product safety and quality control, these tools offer unparalleled visibility. Fixed, smart sensor cameras streamline IIoT data integration and are perfect for users requiring built-in, on-camera analytics and alarm capabilities. Similarly, image streaming fixed cameras adhere to industry-standard GigE Vision protocols, facilitating seamless communication with machine vision applications.

Unnoticed leaks in compressed air, vacuum, and food-grade carbon dioxide pose significant risks to the food and beverage sector. These leaks can result in product contamination, decreased efficiency, heightened downtime, and safety hazards. Even the smallest leaks can be promptly identified with acoustic imaging cameras, enhancing system efficiency, lowering operating expenses, and upholding the quality and safety standards of food and beverage products.

• Predictive maintenance for electro/mechanical systems across the manufacturing facility
• Monitoring the temperature of oven-baked goods
• Verifying the temperature of microwave-cooked meats
• Monitoring the use of microwaves when drying of parboiled rice and other grains
• Inspecting ovens for proper temperature
• Verifying the proper filling of frozen meal package compartments
• Checking integrity of cellophane seals over microwave meals
• Inspecting box flap glue of overwrap cartons
• Monitoring refrigerator and freezer compartments
• Performing ignition-risk T-class surveys in zoned areas
• Continuously monitoring for fire risk and high-touch temperature issues

Thermal imaging serves primarily as a quality assurance (QA) tool, particularly in ensuring the quality and safety of cooked meat products. For instance, a fixed-mount thermal imaging camera positioned above a continuous conveyor oven can monitor the temperature of chicken tenders upon exiting the oven. The goal is to verify they have reached a safe temperature without being excessively cooked or dried out. Additionally, thermal imaging cameras can be utilized to inspect microwave precooking lines, resulting in improved product quality, safety, and increased throughput, along with reduced energy costs. The thermal image provided depicts bottles being automatically filled, facilitating the removal of overfilled or underfilled bottles. Thermal imaging proves particularly effective in inspecting dark-colored glass or opaque plastic bottles, as the internal temperature generates an image that is invisible to visible light cameras.

Thermal imaging cameras offer versatility beyond cooked food inspections, extending to the monitoring of conveyor ovens. They can also play a crucial role in maintaining oven temperature through a feedback loop system.

Another valuable application of thermal imaging cameras in conveyor ovens involves monitoring temperature uniformity across the width of the cooking belt. In instances where a heating element malfunctions in an electric oven or uneven heating occurs in an air impingement oven, thermal imaging cameras can swiftly detect cooler areas on one side of the product stream.

Compared to conventional contact-type temperature sensors, quality inspections of this nature pose greater challenges. Therefore, thermal imaging cameras serve as invaluable tools in identifying and correcting variability, thereby enhancing quality and minimizing product wastage.

There are software solutions available that enable thermal imaging cameras to identify objects and patterns within images. One notable application of pattern matching is in the production of frozen meals. Thermal machine vision utilizes pattern recognition software to verify the proper filling of food tray compartments.

A related application involves the automated 100% inspection of heat-sealed cellophane covers on finished microwave meals. Using a thermal imaging camera, heat radiating from the lip of the container where the cellophane heat-seal is formed can be detected. The temperature along the entire perimeter of the package can be assessed by leveraging thermal images with machine vision software. This software compares the geometric pattern and temperatures in the image with those stored in a computer memory. Additionally, such systems may incorporate laser marking to identify poorly sealed packages for removal at the inspection station.

Typical Go/No-Go inspection system using thermal imaging cameras.

An aspect indirectly impacting product safety is the integrity of cartons that serve as protective overwrap for food containers. A common and cost-effective method of sealing these overwrap cartons involves the use of heated glue spots on the carton flaps. Traditionally, the integrity of these spot glues was assessed through periodic destructive testing on several samples, a process that proved to be time-consuming and expensive.

With the use of heated glue, thermal imaging cameras can effectively examine the pattern and size of the applied glue spots through the cardboard material. These cameras can be configured to inspect predefined areas of the flaps where glue should be applied, ensuring spot sizes and temperatures meet specified criteria.

The digital data obtained from these inspections is then utilized to make pass/fail decisions on each box, enabling immediate removal of defective boxes from the production line. Furthermore, the collected data is automatically logged into the QA system for trend analysis. This allows for the generation of warnings if an excessive number of boxes begin to exhibit failures.

Another valuable application for thermal imaging cameras involves monitoring container filling operations. While this may not directly impact product safety, it significantly influences yield and compliance with regulations. By defining various areas on the bottle, thermal imaging cameras can detect discrepancies and trigger alarms to remove bottles that are over- or under-filled. Notably, thermal imaging cameras offer distinct advantages over visible light cameras, particularly when dealing with bottles or jars made of dark-colored glass or plastic.

Current application software available for thermal imaging cameras offers a diverse range of functions tailored to support automated food processing applications. This software seamlessly integrates with and complements the firmware embedded within thermal imaging cameras. The imaging tools and libraries included in these software packages are hardware- and language-independent, facilitating easy implementation of thermal monitoring and control systems by food processing engineers.

Thermal imaging cameras themselves offer users various operating modes designed to ensure accurate temperature measurements across different conditions. Two commonly found functions in these cameras are the spotmeter and area measurements.

The spotmeter determines the temperature at a specific point, while the area function isolates a chosen area of an object or scene, providing maximum, minimum, and average temperatures within that area. Additionally, users can typically select the temperature measurement range according to their preferences. Furthermore, most cameras allow users to configure a color scale or grayscale to optimize the camera image in conjunction with the selected temperature range.

In conveyor oven applications, the area function is typically used because pieces of cooked product are often randomly located on the conveyor. The camera can be programmed to find and measure the minimum and maximum temperatures within the defined area. If one of those setpoint temperatures were to fall outside the user-defined limits, an application program running on a PC or PLC would instantly trigger an alarm, alerting the operator to check the thermal image on a video monitor or PC to find and remove the bad product, and/or adjust the cooking temperature.

In the case of local monitoring, an IR camera’s digital I/O can be used to directly trigger an alarm device without additional software. However, food processing often benefits from higher level analytics that are available in third-party software that runs on a PC.

These out-of-the-box solutions do not require the writing of application source code. By adhering to commonly used machine vision interface standards such as GigE Vision® and GenICam,™ a wide range of functionality is supported by this software.

A simplified block diagram of conveyor monitoring is shown. One thermal imaging camera is adequate for many applications, or a thermal imaging camera may be combined with a visible light camera to record other target object attributes, such as color.