Proper Calibration and Use of Load Cells

Proper Calibration and Use of Load Cells

Much of today’s repair and assembly work involves having the right tools, and many work sites such as factories or auto repair shops will have such tools on the job. While some labor today is automated, many jobs are best left in human hands, and these workers have simple tools on hand to make this possible. Load cells, for example, such as strain gaging cells or hydraulic cells can measure the exact weight of an item. In other cases, torque wrenches are necessary for tightening nuts and bolts, and many auto shop workers may use these tools during a hard day’s work. Of course, tools may sometimes become faulty or break down, and different ones work better for a given job. What is there to know about different loading cells and torque wrenches in use today?

On Load Cells

Put simply, a load cell is any device that measures resistance on its platform. Most load cells could simply be called measuring scales, since they will have an item placed on their flat bed and the pressure exerted will be registered by the load cell’s mechanisms. This is a simple enough concept, but in fact there is more than on way to do this. In today’s American industries, five different load cell models are put to use: strain gauge load cells, hydraulic models, diaphragm load cells, spool type load cells, and ring type load cell models. Different ones may be employed at the work site based on the ambient temperature or the gross weight of the items being weighed. In fact, the factor of whether or not the work site can provide electricity may impact what sort of loading cell is used. In cold environments, for example, hydraulic load cells may be optimal since they can operate at temperatures as low as -60 degrees Celsius, or -76 degrees Fahrenheit. A research station in Antarctica, for example, may make good use of these since they don’t need power and can endure temperatures typical of that continent. Whatever the model, load cells are a non-intrusive, accurate means of providing measurement data for nearly any user. So long as they are calibrated correctly for work, loading cells may have accuracy within 0.03% to 1%, based on the load cell type. In many areas of work, it is very important indeed for a worker to know the exact weight of an item, down to the finest ounces or grams.

Torque Wrenches

Meanwhile, torque wrenches are widely used in today’s manufacturing and other industries, and have proven themselves useful for a century. First invented by Conrad Bahr in 1918, these wrenches were first developed to fasten nuts or bolts for the New York City water department. They are still used in this manner, but can be used for car wheel bolts and other functions as well. Put simply, such wrenches use torque, or twisting power, to fasten something in place and make use of the tool’s leverage to offer enough power. Such bolts are far too tough to tighten with bare hands, but a torque wrench offers the leverage needed to get the job done. Advanced toque wrench models are also available, and may be found in many tool kits. But of course, it is also possible to apply the wrong amount of force with these wrenches, so they may have gauges on them. too little force means that the job isn’t done, and too much force may damage something.

If a worker suspects that a torque wrench’s pressure is incorrect, they may make use of a calibration wrench to set everything straight. For those not aware, a calibration wrench is used not for everyday work, but rather as a control group for other wrenches that may be mis-calibrated. A worker will use each wrench on a bolt or other bit of hardware, and compare the possibly-faulty wrench’s readouts to that of the calibration wrench, which is a known quantity. Now, the worker may use that difference as a reference to readjust the faulty wrench, and set its pressure readings to correct amounts. This may prevent a worker from using a poorly calibrated wrench to either leave bolts insufficiently tightened, or over-tighten something and cause damage to expensive hardware, such as on a car wheel.

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