Rigorous testing and certification helps Thayer Scale’s equipment provide accurate readings its customer can rely on.
Getting the measurements right adds up. If a scale does not measure and totalise, the producer could be losing thousands of dollars in miscounted product or could be overcharging its customers, creating an integrity issue or even legal problems.
U.S. Minerals, a producer of slag product for roofing and abrasives industries, was using off-the-shelf conveyor belt equipment and couldn’t verify the accuracy of the material it was conveying.
To resolve the issue the company decided to invest significantly into its facilities. The company knew it needed a conveyor belt scale but was not aware of the difference between low-cost belt scales and certified-for-trade belt scales.
Peter Sirrico, North American sales manager at Thayer Scale, told ABHR that attaining a National Type Evaluation Program (NTEP) certification allows the company to sell certified scales in the United States. ‘Certified’ in the US indicates that the device meets a tolerance of + 0.25 per cent and/or + 0.1 per cent and has passed testing to verify its conformance.
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“A model is submitted for lab testing, where it must prove it can maintain a certain static test tolerance. Then it is tested in the field. This portion of the assessment is the material test phase using a conveyor or system that requires a high level of accuracy. This is the permanence test. Six months later, the belt scale is again material tested and if it passes with no changes to the metrology, with no ‘K’ factor changes and no adjustment to the span, it achieves its C of C. The key to passing this test as well as to any reliable belt scale is the stability of the scale ‘zero’,” he said.
“The international equivalent is the International Organisation of Legal Metrology (OIML), which Australia uses.
“If you have NTEP certification, you can sell directly from the scale with confidence. In this industry, you live or die based on your reputation, so that peace of mind is vital.”
Thayer Scale has a range of NTEP certified conveying equipment, and successfully made the case to U.S. Minerals to replace its single-idler scale and a rail scale at its LaCygne, Kansas location. Although the site had these scales, several rail cars continued to be overloaded due to a combination of the low accuracy of the belt scale, along with the troublesome method of use for rail scale.
U.S. Minerals purchased a six-idler conveyor belt scale and a single-idler belt scale. The six-idler unit is used for rail car load out and the single-idler unit moves the material onto trucks, which use an in-ground truck scale for weighing that serves as the ticketing mechanism.
The Thayer Scale six-idler conveyor belt scale has weighing accuracy of .1 per cent range and the equipment it was using prior had 2-3 per cent accuracy. The conveyor belt scale is used as needed and has a flow rate of 115 tons per hour.
If U.S. Minerals didn’t have the option of purchasing the Thayer Scale NTEP certified conveyor belt scale, it would have had to make a substantial investment in a rail scale which can run from $500,000 to over a million dollars. The Thayer Scale belt scale is integrated into a required conveyor making it highly efficient. U.S. Minerals expects to yield return on investment for the belt scale in less than six months.
Sirrico said Thayer Scale works closely with its customers to find the right scale for the applications.
“We visit the site, walk the conveyor and take a good look at it. You want to ensure that the conveyor is suitable and there are no outliers that might diminish performance and cause problems. The inspection allows Thayer to select the proper belt scale for the conveyor as well as the one that best meets the expectations of the end user,” he said.
“Honesty is important, which is why we are always up front with our customers. If we don’t know something on the spot, we can get back to them. You’re trying to establish a relationship of trust with them. Our business model is built on relationships that become long term due to the efforts of the external and internal Thayer team.
“That relationship with the customer is vital. Your customers will remember how you work with them. We get a lot of repeat business – with many of our customers purchasing equipment continuously for a decade or more. It all starts with that first visit.”
Thayer Scale’s conveyor belt scales and conveyor weighing systems are designed for a range of accuracies: high accuracy loading and unloading systems, custody transfer and NTEP-approved versions (0.10 per cent– 0.125 per cent), inventory control and processing needs (0.25 per cent – 0.5 per cent), and various stone and aggregate applications (0.5 per cent to 1 per cent).
Customers in pulp and paper, wood pellet production, ship, truck, rail and barge loading, fertiliser, mining, ore, copper, and coal industries utilise the company’s conveyor belt scales in severe applications and in some of the harshest manufacturing environments. Thayer Scale conveyor belt scales are built to survive and can last in service for decades even in the most extreme operating conditions.
The NAR belt scales have been proven in service demanding ±0.125 per cent accuracy through independent certification. The weigh bridge features exclusive rocking flexure suspension in the approach-retreat configuration.
Measurement sensitivity is high, deflection is low, and the load cell is isolated from the error-inducing effects of extraneous lateral forces, off-centre loading, foundation distortion, inclination hold-back forces, and high sporadic shocks and overloads. Tare load is mass counterbalanced to create superior signal to noise ratio in weight sensing, orders of magnitude better than belt scale designs supporting full tare load on the load sensor.
Sirrico said the company is continuing to grow, with last year being one of the company’s best.
“We have equipment that works across the spectrum of applications, from food, wood, chemical, steel, ore, and more,” he said.
“We are looking to continue developing new products that are even simpler and easier to maintain.
“Thayer has also grown in the Pacific region, with exciting things to come.”