This feature originally ran in the June 2011 issue of Food Manufacturing.
What are important issues food manufacturers must consider when making decisions about the implementation of instrumentation and weighing devices in their facilities?
Fred Cox, Vice-President of Sales/Marketing, Cardinal Scale Manufacturing Company
Water combined with high-pressure cleaning takes its toll on electronic equipment. Food production facilities are best suited for weight displays that carry an IP69K rating and are resistant to high-pressure water jets of up to 1,450 PSI and temperatures of up to 176 degrees Fahrenheit.
Additionally, in food manufacturing, scale operators require a keypad that is resistant to the rigorous demands of harsh daily operation. The new polycarbonate technology of Cardinal’s 190 STORM indicator incorporates what are called capacitive touch keys, which are manufactured behind the clear polycarbonate panel instead of in front. This prevents the operator from damaging the scale with sharp objects, such as scissors or knives, used during food processing. Capacitive touch keys work much like the display on new smart phones, and operators find it very easy to touch the tare key or associated functions during the weighing process.
New technologies, such as color weight display readouts, also improve on productivity by alerting the operator of accepted weights. Check-weighing light features assist the operator who may be monitoring several weight stations at a time. They can instantly recognize accepted or overweight readings from a distance, which also insures the repetitive weights, further improving on overall production costs.
Glenn Zalusky, National Accounts Manager, Rice Lake Weighing Systems
Moisture and heavy, repetitive use in food processing presents a challenging environment for electronic scales. Such applications need scales designed specifically for food processing.
Environment Conditions — For scales requiring daily washdown with hot, high-pressure water and chemicals, look for NEMA 4X stainless steel enclosures with an IP69K rating. In a damp, wipe down or low-pressure washdown application, IP66 is sufficient.
In a dry or mild food processing application, a stainless platter or scale deck on alloy steel cells works well. If scales are frequently washed down or are in very humid environments, specify stainless load cells made for hostile environments featuring welded seals and potted cavities.
Data Collection — Before choosing protocols, ask three questions:
- What data do I want?
- Where will the data go?
- How will the data be used?
Then choose between serial, Ethernet TCP/IP (cabled and wireless) and common industrial protocols such as A-B Remote I/O, Profibus DP, DeviceNet, EtherNet IP for A-B PLC, and ControlNet. Instrumentation that allows adding option cards will provide the most flexibility for future expansion.
Security — Most food producers limit access to scale setup and configuration menus to shift supervisors or maintenance groups. Look for scale instrumentation with administrative passwords and the ability to lock out keys.
Carl Joslyn, Market Manager, OHAUS Corp.
Consistency, accuracy and durability are challenges food professionals must repeatedly address to provide a quality product. Supplying customers with the taste and quality they expect –at a steady price point– greatly contributes to repeat business.
Manufacturers often measure ingredients not by volume, but by weight, which is critical to the final product. Doughs and preferments, for example, can rely on just a half-gram of yeast to catalyze fermentation. The slightest amount of added yeast can cause dough to over-ferment, affecting strength, color and flavor. On hectic deadlines, it can ruin more than just a product; it can result in lost customers and a tarnished reputation. Enhanced weighing and measuring can provide more than consistent quality, however. It prevents over-application, which cuts into profits.
Scales can grow increasingly inaccurate as weights approach the scales’ limits. Simultaneously, they must be able to withstand the messy, wet or powdery substances in daily manufacturing. Infrared sensors for “touchless” operation can mitigate the damaging effect of harsh processing environments on scales. “Touchless” scales can also prevent cross-contamination or unwanted residue on the scale.
Shirl Lakeway, Jr., President, Food Technology Corporation
One important factor relating to instrumentation selection is an understanding of the practical aspects of the tests required and the specifications necessary to perform them. Many focus on “accuracy” and assume that is the most important specification when deciding on a purchase.
While accuracy is of paramount importance in many weighing applications, when it comes to food texture testing, repeatability is the key. If one is testing a food item that can vary from test to test, then accuracy to an ounce is not required. As long as the measurements are repeatable, then pass/fail decisions can be relied on over time.
It is very typical in food texture testing to get a high standard deviation for a series of test results on the exact same product. Since food is biological, variance within the same lot is expected. This is why several replications of the same test must be done and the data averaged to reach a final result.
Food texture application results are not scientific units of measure. If the system measures a force, and the actual force is 50 pounds, but it displays 55, it really doesn’t matter as long as it always displays 55 when 50 pounds of force are applied. This is an extreme example but illustrates the point. A measurement system can be marginally accurate but still perform the tasks required.
John Brown, Sales and Marketing Coordinator, WeighPack Systems, Inc.
When selecting instrumentation and weighing systems, food manufacturers must consider the needs of different stakeholders in the company.
Sophistication — A company will need to select equipment that is in-line with existing or future infrastructures. Food manufacturers should look for easy-to-service, PC-based equipment using readily available software including Windows™, Crystal Reports™ and Skype™. Instrumentation systems should integrate with resource planning and networking software.
Food Safety — Food manufacturers should consider equipment with 304 food-grade stainless steel, washdown capability and designs that eliminate areas where bacteria can hide. Users should pay particular attention to equipment that features food-grade contact parts, a hinged hopper that provides access for cleaning and product changeover and quick disconnect parts. Linear scales with airlines not mounted to the weigh bucket will not have to be disconnected and can eliminate risk of contamination.
Serviceability — Ease of servicing is often overlooked in equipment design. Food manufacturers should consider devices with an open frame design or ones in which all electronics have been removed and located remotely in a centralized enclosure at eye level.
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