There are a wide variety of measurement tools at our disposal, and understanding how to choose the right measurement tools is important.
Measurement Tools: Torque Wrench and Torque Sensors
This tool was developed in 1918 by Conrad Bahr. He worked for the New York City Water Department, and his goal was to develop a tool that would apply a specific torque to some kind of fasteners, such as a bolt. His invention worked beautifully and is still popular today. Today’s custom torque sensors are calibrated to about 360,000 pounds per square inch but are capable of exceeding that limit. Torque sensor units, as well as load cells, are normally designed to work within a wide range of temperatures, from -452 degrees Fahrenheit to 450 degrees Fahrenheit. The torque sensor system is capable of detecting cracks from fatigue that are as small as 0.01 inches.
Measurement Tools: Load Cells
Most modern load cells are using a technology known as strain gauge. Developed more than 40 years ago, this technology is well proven. Load cells are used for weight measurement because of their high level of accuracy in load measurement data and because they are not intrusive. This, of course, depends on proper installation and calibration. Given that, accuracies of 0.03% to 1% can be expected, depending on the type of load cell in question. The five different types of load cells are the strain gauge, ring type, spool type, hydraulic load, and diaphragm load cells. They are named for the primary and secondary elements used by the cell to sense force. Each has its particular strength. Hydraulic loads, for example, can operate at temperatures as low as -76 degrees Fahrenheit.
Measurement Tools: Calibration
Calibrating an instrument is done by comparing the measurements of two different instruments. One is known to be accurate and is referred to as the standard device. The other is the unit being measured for accuracy. For torque sensors, recalibration by the ISO9000 and other standards should be done at a maximum of every two years, but more often is there is significant deterioration. For load cells, calibration is essential due to product liability and safety concerns. Load cells can become less reliable because of mechanical, electrical, or instrumental faults. Although most cells are also required to be recalibrated only once every two years, many users calibrate annually just to ensure that all measurements are as accurate as possible.
These measurement tools are essential for all types of weight and torque measurements in modern applications. Choosing the right one and keeping it properly calibrated is key to maintaining these measurement tools and their functionality in all their crucial applications.