To police fast-paced production lines, checkweighers are used to monitor the weight of each and every package against pre-determined parameters, preventing over and underweight parcels from reaching customers. This not only proactively promotes continued product quality and positive public standing, but also protects the company’s bottom line by safeguarding their investment and improving profitability.
Prior to implementing a checkweigher into processing and packaging applications, manufacturers must take into consideration the scale’s design and durability. Knowing what features and capabilities to look for allows manufacturers to meet safety and sanitation requirements, minimize downtime and equipment repairs and improve production efficiency and visibility.
Scale Safety Certifications
It is crucial that food manufacturing and packaging companies use weighing equipment that complies with strict legislative requirements. As industry trends move toward comprehensive certification programs, understanding the specific accreditations and certifications available can ensure those in the food industry select products fit for that purpose.
The National Sanitation Foundation (NSF) is a global public health and safety organization which certifies products worldwide and sets internationally recognized standards for food, water and consumer goods. Products and equipment featuring NSF Certification have been independently tested and verified to ensure that all public health concerns related to the design, operation and cleaning of the equipment have been addressed. Additionally, the American National Standards Institute (ANSI) oversees the creation and use of thousands of guidelines and standards that protect the safety and health of consumers, while 3-A Sanitary Standards (3-A SSI) focuses on hygienic equipment design for the food and beverage industries.
NSF International, ANSI and the 3-A Sanitary Standards Committee have collaborated to develop a recognized standard for food processing equipment. Any product bearing the NSF/ANSI Standard 3-A 14159-1 -2010 accreditation can be considered to have met stringent standards for use in the food industry - specifically hygiene requirements for the design of meat and poultry processing equipment. Therefore, when selecting a checkweigher for food processing and packaging applications, users should look for a scale featuring certification that demonstrates its suitability for the industry.
Scale Designs for Food Applications
On a food packaging line, fast and accurate checkweighing is necessary to maintain high-level production, and scales should be designed to promote this objective. Selecting a scale with high speed value capturing capabilities can have a direct impact on your bottom line; allowing operators to increase throughput and pack rate for a faster and more efficient production line.
Since checkweighers are used to weigh everything from raw foods, such as meat and dairy, to finished, packaged products, they should be constructed of a suitable, non-toxic material that is unlikely to break or fracture. This prevents broken fragments and splinters from contaminating the product. Also, the number of joints, rivets, screws and dead spaces must be minimized to provide an easy-to-clean surface and minimize the potential number of food trap areas that pose a health and hygiene risk.
In applications where raw materials are being weighed, scales must be designed to withstand frequent, heavy washdown procedures. The combination of water, chemicals, high pressures and temperatures used in this cleaning process can prove fatal for electronic circuits and instrumentation. The Ingress Protection (IP) rating system is an internationally recognized scale that relates to proven protection against environmental factors such as liquids and solids. A product with the highest rating available, IP69K, offers complete assurance that it has been subjected to a challenging set of tests to ensure protection against penetration of high pressure, high temperature water and dust particles - making it ideal for use in conditions where equipment must be carefully sanitized. While this testing procedure can be performed by the scale manufacturer themselves, opting for a scale that has had its IP rating independently verified can offer further assurance that the equipment is fit for purpose.
In these heavy washdown environments, equipment can often be subjected to rapid temperature changes. Extremes of temperature inside and outside the enclosure can result in expansion and contraction of gases, which in turn can lead to moisture and humidity becoming trapped inside. To prevent equipment malfunction of result inaccuracies associated with moisture ingress, some checkweighers feature specially designed vent technology that helps neutralize the pressures between the inside and outside of the enclosure and keeps moisture out.
Additionally, selecting the appropriate scale material can also increase scale durability. Though scales constructed of high impact plastic resists expansion, contraction and the subsequent condensation build-up, stainless steel is far less likely to crack or break, providing a more durable and hygienic solution. Scales constructed of stainless steel provide superior corrosion resistance, feature a non-absorbent finish and offer an inherent tolerance to temperature extremes. These characteristics enable checkweighers to operate even when subjected to a combination of water, chemicals, high pressures and temperatures that typically prove fatal for electronic circuits and instrumentation.
When used to weigh raw food products, the surface finish of the stainless steel weighing platter can have a significant effect on its hygiene characteristics. Food contact areas should have a fine brush finish to reduce the risk of bacteria growing on the surface. As an additional measure, the stainless steel should undergo a pickling and electro-polishing process to remove any impurities on the surface of the stainless steel. The rougher a surface finish is, the more likely it is that food will stick to it, creating a breeding ground for bacteria and micro-organisms. Designed to meet the strict hygiene standards demanded by the food industry, this pickling and polishing process reduces the tiny peaks and troughs found on the surface of the metal. Not only does this create a clean cut finish and reduce the likelihood of contamination, it also provides a surface that is far easier to clean.
Also, scales engineered for food applications should avoid fully welded tubular designs that can prove hard to clean. A welded structure can result in bacteria becoming trapped within the tube and thriving in the constantly changing atmosphere often found within the food industry. Conversely, base designs with flat bases and open corners ensure that any food particles can be quickly and easily washed away during high pressure cleaning.
With connectivity and communication being pivotal to production efficiency, checkweighers that offer data acquisition and management capabilities can directly impact a company’s capacity for profitability. To maximize process visibility and control, some checkweighers offer a built-in interface, Ethernet, USB and RS232 to share information and deliver effective data management. These options allow the scale to be hard wired inside the indicator, or wirelessly connected to remove all cabling in demanding environments. This enables scale solutions to collect, store and interpret data in virtually any industrial environment.
For instance, in a heavy washdown environment, an increased number of cables provide more areas for bacteria to hide which, in turn, increases the length of the cleaning process. By offering wireless connections, users can remove unwanted cables for an efficient and timely washdown procedure. This minimizes downtime, avoids unnecessary lost production and prevents costly equipment damage.
Along with durability, constant access to critical data also improves profitability. Scale displays that are easy to read deliver higher visibility and allow operators to obtain more information at a glance. Checkweigher displays that feature multi-segmented, under/overweight graphs provide the user with a clear indication of how close a weight is to the acceptable target tolerance at any given moment. Scales can also be reinforced to include an external audible alarm, ensuring the highest level of accuracy and awareness.
Checkweighers should also be easy to use, facilitating simple implementation and interaction by allowing operations to quickly and easily set or change target tolerances. Equipment featuring a push-button front panel allows users to change parameters directly on the scale itself, enabling it to constantly adapt to changes in production. Further, scales with memory functions offer the option to set pre-program targets that can be used to simplify the set-up of additional production lines. Checkweighers with a range of statistical data packages built into the scale enable users to monitor and control processes directly on the line or via feedback to a central PC database for constant access to critical data. Plus, with remote capabilities, a scale can receive target weights and tolerances remotely, which can speed up production line set-up and ensure pack line consistency.
The reality of life on a production line means that a checkweigher is often subjected to abuse and harsh operating conditions; from shock loading caused by packages being dropped into the scale, to spray jets used in washdown procedures causing the scale to be bumped or knocked to the floor. While a durable design may go some way to compensating for this abuse, selecting a scale that has the capability to transfer shock loads and overloads away from the load cell will ensure that the accuracy and performance of your weighing equipment is not affected.
With industries becoming more competitive and customers gaining a greater awareness of the marketplace, investing in a checkweigher can prevent costly mistakes in package weighing applications that result in dissatisfied customers or costly giveaways. By selecting a scale that combines hygienic, durable design features with connectivity capabilities, manufacturers can improve production efficiency, minimize downtime and enhance product quality to promote continued company profitability.