WORKING PRINCIPLE OF COMPRESSION LOAD CELL
Compression load cells can be used wherever compressive forces need to be measured. They are barrel-shaped devices measuring the applied force at a centre point. Canister compression load cells are the most common type of load cell. The load cells feature a built-in spring element. This element is a piece of metal that is elastically deformed under load and recovers the moment the load is removed. This deformation or strain is picked up by strain gauges installed on the metal element and converted into an electrical pulse. In a compression load cell, the spring element is compressed when the force is applied. A special version of the compression load cell is the ring torsion load cell, which features a threaded bore for an adapter. The force is always applied at the centre of the load cell so that eccentric loads can be measured with great accuracy.
Compression load cells are commonly found in heavy-load scales in the range of multiple tons. They are thus frequently used in silo scales, coil scales, heavy-duty scales and cargo scales, as well as for force measurements in the process industry.
As compression load cells are mainly used in industrial applications, they come in sturdy housings. Most compression load cells meet the requirements of IP67 or IP68 (protection from dust ingress, splash water and temporary immersion). The main technical parameters of a compression load cell are its rated load, limit or breaking load and minimum scale division, which are stated in the data sheet. Based on this information, the scales manufacturer can determine the permissible tare weight as well as the measuring accuracy of the weighing scales. As compression load cells are very compact devices, they are particularly suitable for installation in systems where space is confined. For verifiable scales, the compression load cells must of course also be verifiable.