A load cell is a transducer that is primarily used to convert force into measurable electrical output. Being the most common type of force sensors, they are typically differentiated based on the way they detect weight or as per the type of output signal.
Here are some of the cell load types that you may find useful:
Hydraulic load cells
Hydraulic load cells come with force-balance functionality, which helps measure weight using the change in pressure of the internal filling fluid. Force acting on a loading head is transferred to a piston that is attached in a rolling diaphragm. As a result, the filling fluid confined that is inside an elastomeric diaphragm chamber is compressed.
The pressure of the hydraulic fluid is directly proportioned to the force. Hence, it increases as the level of force amplifies. This pressure can either be transmitted for remote indication or indicated locally with linear output, which remains unaffected by the temperature or amount of fluid present in the chamber. The applications of hydraulic load cells typically include bin, hopper, and tank weighing.
Pneumatic load cells
The functionality of pneumatic load cells is primarily based on the force-balance principle. Using multiple dampeners, these load cells offer a higher level of accuracy compared to hydraulic devices. They are mostly used to calculate small amounts of weight, particularly in industries where safety is taken extremely seriously.
There are multiple advantages to using pneumatic load cells. Not only are they explosion-proof, but they are also insensitive to temperature variations. Furthermore, they don’t contain any sort of fluid that can cause contamination in case of an adverse event, for instance, if the diaphragm ruptures. That being said, pneumatic load cells speed of responsive is relatively slow.
Strain-gauge load cell
Strain-gauge load cell functions simply by converting the load into electrical signals. There’s a beam or structure member placed to support the gauges, which deforms when a certain amount of weight is applied. Strain-gauge load cells provide accurate results while offering cost benefits due to their low unit costs.
Typically, four strain gauges are used in order to ensure temperature compensation and maximum sensitivity. Generally, two gauges are in compression while the other two gauges are in tension. All four gauges are wired with compensation adjustments. When a certain amount of weight is applied, the electrical resistance of the gauges is changed in proportion to the force.
Final Words
We looked into three of the most popular types of load cells, but there are many other types available, including piezoresistive load cell, inductive and reluctance load cells, and magnetostrictive load cells, just to name a few. Each of them comes with its own unique functionality and applications, of course.
Looking for high-quality load cells and force sensors? Get in touch with Contact Instruments today! We’re a Canada-based oilfield instrumentation manufacturer and provider that offer premium quality load cells and force sensors. Moreover, we also provide custom cables, overmolded cable assemblies, and other oil rig instrumentation at competitive rates. To find out more, call us at 780-955-8998 or visit our website.