For any engineer or other worker dealing with machines and their repair and maintenance today, having the right tools for the job is critical for success. Some of these tools include the use of torque wrenches, and while these tools are very useful by applying torque (twisting power) to a bolt or other item, they will, over time, lose their accuracy on their readouts and will have to be calibrated again so that a worker uses them properly and knows how much force is being exerted. Some rotation and torque wrenches will have built-in components to stop the torque power after a pre-set limit has been reached, but other such wrenches will rely instead on a readout that measures the power being exerted, and it is important that this readout stays accurate. What should a worker do when their wrench’s readout is starting to get inaccurate? And on the topic of hard work and measurements, what different types of load cells are used, and will they require measurement and calibration work, too?
The Wrenches
A wrench that uses torque is very useful, but once its readout starts to become inaccurate, the worker may not be able to apply the correct torque during a job, so calibrations will have to be done. To get started, a worker will use both the faulty wrench and one whose measurements are already accurate, and the latter is known as a known magnitude, or a correction device. It can be used for comparison with the wrench whose readouts have become inaccurate. Thus, a worker can use both on an item and compare their readouts, and make adjustments to the afflicted wrench until its measurements become consistent with those of the other wrench, and the calibration is complete. Ever since 1918, when Conrad Bahr invented torque wrenches at the New York City Water Department, these tools have become industry standards, along with the digital and analogue readouts of the power being exerted with them. Accurate readouts will always be required.
The Types of Load Cells
A load cell sensor will be attached to one of five general categories of load cells, and what these devices have in common is that they measure the force exerted by pressure, or resistance, and convert this into a meaningful readout that workers can see and make use of. Those five types are gauge type, hydraulic, diaphragm, spool, and ring type. In the case of hydraulic load cells, they can stand up to a variety of temperatures and conditions, and they can even work in temperatures as low as -60 degrees Celsius, or -76 degrees Fahrenheit. And when properly calibrated, a load cell of any of these types can be highly accurate; depending on the exact type, the loading cells can achieve accuracy ratings of 0.03% to 1%. Meanwhile, strain gauge load cell technology has proven itself particularly useful and accurate, and has proven its value for over 40 years and will probably continue to be useful well into the future, especially since it is growing more cost effective by the year.
