Many businesses across a wide range of industries require scales in their operations. As with any other piece of equipment, it’s vital that you understand the best type for your company, setting, and its intended applications.
The differences between a commercial and industrial scale may not be readily apparent, but understanding the difference can help you make the right purchase for your business. In fact, comprehending the differences may even help prevent you from falling out of compliance.
Industrial Scales vs. Commercial Scales: What’s the Difference?
Generally speaking, commercial scales are typically used in businesses that weigh small amounts of product or produce, while industrial scales are designed to handle heavy-duty work loads. Industrial weighing equipment, on the other hand, are typically more durable than their lighter counterparts, which makes them ideal for hazardous production environments.
However, there are more specific differences you should consider to truly understand their different usage applications and ideal environments.
Commercial Scales Require Certification
Commercial scales (also called “Legal for Trade” or “NTEP Certified” scales) are usually used in transactions where both the purchaser and the seller are present. For example, a commercial scale would be used at your local deli, where the meat is cut and weighed in front of you, or in a candy store where root beer barrels are sold by the pound.
Essentially, if the merchant has to separate the product, weigh it, and put a price tag on it in front of you, then a commercial scale is required. However, if the manufacturer were packaging one-pound bags of their product and accurately labeling the contents, they wouldn’t typically be required to use a commercial scale.
In fact, they can usually even package their product in any way they’d like, even by volume, just so long as they guarantee that it contains the amount that’s advertised on the bag. The merchant could even have an industrial scale in their backroom with which they make their own packages, label them, and put them on the shelf for sale.
You’ve more than likely seen phrases indicating labeling methods on various packaged food items. Take a look at a cereal box the next time you’re having breakfast. There may be some sort of marking that explains how the product is weighed.
The National Bureau of Standards Regulates Commercial Scales
They determine how the scale is allowed to operate, the accuracy requirements, how the price-per-pound must be entered, and how labels must be printed, among many other policies.
These regulations are in place to prevent the merchant from cheating the customer, but the accuracy requirements of these scales are not extremely high. Generally, nobody is going to feel cheated over 1/100th of a pound of root beer barrels.
While industrial scales are not specifically designed to meet “legal for trade” requirements, many of them do. Industrial scales are typically designed to achieve the highest accuracy possible. They are also designed for use in industrial environments, which are usually harsher than your average deli counter or candy store. A regulated commercial scale would probably corrode if it were exposed to the kind of working conditions present in an average workshop.
Imagine if that scale from the deli counter was installed in the same place where cold cuts were packaged. Even though the environment is quite sterile, the additional moisture, and potential for extreme temperature shifts, could damage the unit. Industrial scales are needed for these situations.
Strain Gage Load Cells for Industrial Scales
While any load placed on a scale’s platform is transferred to the load cell, there are different kinds of transducers that can be attached to the spring element of the load cell.
What is the Spring Element of a Scale’s Load Cell?
The spring element is the precision-machined piece of metal that is attached to the underside of the scale’s platform and the floor of the scale. When a load is placed on the platform, this piece of metal bends.
The Most Common Transducers are Strain Gages
Over the last sixty years or so, strain gages have been the standard for industrial weighing equipment. The gages are attached to the section of the spring element called flexures, which cause a change in the electrical resistance of the gages when bent by the spring element.
The strain gauges are wired together to form a Wheatstone’s bridge, whose voltage output changes as the resistance of the gages changes. This voltage output is sent to an Analog-to-Digital Converter, which changes the output to a digital signal. This is then sent to the digital indicator, where the output value is numerically displayed and recorded.
Digital indicators attached to this kind of equipment can do far more than simply serve as a static display. Sophisticated models can log data and store it somewhere like a connected USB device for future analysis.
Other options include the ability to transfer it over a serial cable or a network. Companies that need to leverage modern mobile technology can have data from their industrial scale sent to an online spreadsheet. The spreadsheet can then be accessed by any technician, even if they’re not in physical proximity to where the measurement is being collected.
Aluminum Strain Gages vs. Stainless Steel Strain Gages
Often, strain gage load cells are manufactured out of inexpensive metal, such as aluminum. While aluminum load cells aren’t necessarily inferior, they are when it comes to the strain gauge design specifically.
Because the flexures of a strain gage load cell need to be fairly thin, a flexible metal like aluminum leaves the load cell vulnerable to damage from shock and overloading. Since we manufacture our own load cells at Arlyn Scales, we have a choice in construction material.
Instead of aluminum, we opt to use stainless steel for all of our strain gauge load cells. Stainless steel improves the accuracy of the load cell, increases the scale’s longevity and durability, and prevents inaccuracies due to distortion.
This is especially important in industrial environments where loads of as much as 20,000 pounds or more are weighed every day. This is also important for those who need durable scales that can stand up to other kinds of abuse that aren’t necessarily related to mere mechanical shocks.
Consider how dirty an industrial environment can be.
Some industrial scales feature additional coatings, in addition to stainless steel strain gage load coils, so that they can resist corrosion or other types of damage. Coating the platform may also help to reduce the risk of damage when working in a corrosive environment.
Ultra Precision Industrial Scales
One of the major dilemmas when it comes to strain gage scales is the dichotomy between capacity and resolution. A scale’s capacity is the heaviest load the scale can accurately weigh, for example ten pounds or twenty thousand pounds.
The resolution is the smallest increment of weight that a scale’s numeric display can indicate, (for example, 0.1 or 0.0001). When it comes to strain gage scales, the higher the capacity of the scale, the lower its resolution, and vice versa.
Users of extremely high-capacity scales that employ this kind of technology don’t have the luxury of enjoying precise resolutions. In many cases, this shouldn’t cause much of a problem.
If a technician were to be off by even 100 pounds when weighing a truly massive load, then this might not cause any problems. Junkyards and other similar facilities don’t have to worry about this level of resolution normally.
Force Restoration Scales Provide Extremely High Resolutions
Once the need for extremely high resolutions became clear, force restoration scales served that market. However, these scales are expensive — both to purchase and to operate — and they’re prone to drifts in accuracy due to temperature and air current.
The other, and perhaps most important, setback with MFR scales is the fact that they do not provide much in the way of capacity either. While higher resolutions are possible at higher capacities, these capacities top out at around 50 pounds.
SAW Transducers are Inherently Superior to Strain Gages
However, there was still a market of manufacturers and researchers left underserved by both scales. After experimenting with various technologies, we found that Surface Acoustic Wave (SAW) was the best way to achieve extremely high resolutions (up to .0001 pounds) at far higher capacities than previously thought possible (1000 pounds).
With a transmitting transducer attached to one side of the spring element and a receiving transducer attached to the other, a surface acoustic wave is sent between them. The receiving transducer detects the wave signal and then an amplifier magnifies it and sends it back to the transmitting transducer.
The frequency of this wave depends on how far apart the two transducers are. When weight is placed on the platform, the distance between them increases, and the frequency of the wave changes. By measuring this frequency digitally, we are able to determine how much weight has been applied.
What Makes SAW Load Cells Superior to Strain Gages?
SAW load cells are inherently better and more accurate, in part, because there is no need to convert an analog signal into a digital one. Additionally, they are more stable over time, they increase the useful life of a scale, and they are not prone to drifts in temperature, like MFR scales.
We also manufacture these load cells using a special aluminum alloy, which was chosen for its hardness, spring characteristics, lack of plastic deformation, and its temperature performance. This gives you the freedom to deploy highly accurate technology in areas that might present problems for more sensitive pieces of weighing equipment.
SAW Scales are Ideal When Minute Precision is Required
As these numbers suggest, these scales are remarkably sensitive and can provide accurate weights for objects that are quite small. Laboratories and workshops that need to weigh tiny samples could benefit from this kind of technology. Tare weight is of particular concern in these applications.
When the container can potentially weigh more than the sample on a scale of several orders of magnitude, technicians need something that’s sensitive enough to tell the difference. These are also the kinds of applications that temperature drift would make the biggest impact, so SAW load cells tend to be a solid pick.
Weigh Your Options with Superior Scales from Arlyn Scales
At Arlyn Scales, our main focus is to design and manufacture industrial scales that are precise, adaptable, durable, and high quality — all at the lowest cost possible. Because we manufacture our own products and their subassemblies, we’re able to ship our products factory-direct, which means some of the lowest prices on the highest quality equipment in the industry.
If you’re not sure what kind of scale best suits the work you do or the industrial environment in which you work, contact our team today. Our customer support staff will walk you through the selection process and help you determine what features you do and don’t need, helping you to find the most accurate and cost-effective solution available.