Load cells are transducers that are designed as measuring devices. They gauge and monitor forces of compression, tension and shear by converting sensed mechanical force into measurable electrical signals. This technology is commonly employed for mechanical and industrial testing, ongoing system monitoring, as components in devices like industrial scales and other areas of the manufacturing, processing, and testing industries.
The two categories that load cells measure most often are compression and tension force. To help with these measurements, both compression and tension load cells alike, use a small device called a strain gauge. Strain gauges measure an object’s strain, weight, or force output by converting internal deformation into electrical signals. A less frequent companion of the load cell is the piezoelectric sensor, which utilizes piezoelectric crystals to measure strain, movement, weight, and vibrations. Two common sensors that fall under the piezoelectric umbrella are pressure and force sensors. Similar to load cells, they measure applied force, pressure, and strain of gas pressure, liquid pressure, and altitude. Many are surprisingly strong for their size, able to hold or support several tons. For very small applications, operators use miniature load cells. Read More…
Other available equipment that supports strain gauges and load cells include force transducers, torque sensors, and load sensors. Regardless of the supporting equipment used, after the information is collected, it is sent to a recorder or another computerized data collection system. These systems are either analog, which uses voltage, or digital; of the two, digital load cells are more popular because they are faster, more accurate, and have better resolutions. If and when they discover any variance in the system they’re monitoring, load cells sound an alarm or shut down completely until the issue is understood and corrected.
Load cells, as well as pressure sensors and gauges, have a wide variety of specific applications. For example, warehouse workers use load cells to determine the exact weight of loaded pallets. In food processing, load cells and pressure sensors give a precise ingredient measurement and distribute them accordingly during packaging. Other applications include calibration systems, fatigue testing in research and development laboratories, push-pull testing and flow measurement, bridge beam tension strength testing, railcar weighing, and truck scales.
Absolute pressure transducers/sensors are designed to accommodate pressure increases by providing output voltage increases, created with the help of a vacuum sealed or near vacuum sealed internal reference chamber. With a low-profile structure, bending beam load cells are made for integration into restricted areas. S-beam load cells are, as one might expect, “S” shaped. They provide superior side load rejection, and, if they are compressed or under pressure, an output. Platform load cells, also called single point load cells, are designed to collect accurate readings no matter the load position on the platform, while, operating with a similar principle, multi-load cell scales maintain extreme accuracy by taking readings from more than one point on the scale. Interface load cells serve larger systems that constantly measure torque and force. Load cells give weight, pressure, and mass measurements with readings within .25% for loads of all size, from very small, to several thousand tons, to everything in between.
Before selecting or setting up a load cell for your application, you need to investigate a few factors, such as load cell capacity and load cell positioning. To calculate load cell capacity, make sure to consider the following: maximum force value, the dynamics of the system (i.e. frequency response), the load cell’s response to the placement of a transducer in the force path and how much extra weight the load cell can handle. Note that load cells can have between four and thirty gauges and that the more gauges inside the load cell, the greater the cell sensitivity in picking up and recording variances. When your put load cell into place, you must think about whether the load cell will be in the primary load path or whether it will measure forces remotely, as well as if there are any physical changes of the space that need to implemented for size and mounting, the level of accuracy required and what potential problems may arise from the environmental elements to which load cell will be subject. Consider these carefully for accurate readings and load cell placement, greater safety on the factory floor, in the lab and beyond.