An executive of Chile’s Protorq said the company uses Valley Forge & Bolt’s SPC4 load-indicating technology to measure bolt tension.
The technology was used because bolt tension is a more critical spec than the bolt torque, Carlos Recart, executive director, Protorq, said.
SPC4 bolts and studs have built in indicators that measure clamp load in real time. Data is relayed by a built-in gauge, a handheld external meter, or Wi-Fi-enabled remote meter. Fastener load is expressed as a percentage of yield.
SPC4 tension measurements are accurate to within roughly 5%, whereas typical torque-measurement methods are only 20% accurate, Valley Forge & Bolt reported.
In one instance, SPC4 technology helped reduce downtime for a Protorq customer that had bolts that were continually breaking in a ball mill, Recart said. Workers there had not been achieving the appropriate clamp load for the bolts because they had been relying on torque, not tension, as an indicator, he said.
Suspect joints were replaced with SPC4 bolts and fasteners. Users could then quick-connect the handheld meter’s probe to the end of the bolt, get the fastener load, tighten to specs and save the data. Tension is checked and corrected in the same way.
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