Load cells are able to convert force into an electrical signal and are used to calculate the force or weight in a variety of applications – including bending compression, tension, and other forces. Here’s everything to know about load cells and their application.
How Does a Load Cell Work?
A compression load cell, in particular, is a device created to measure compression while holding a load at one point. Unlike tension load cells that measure a pulling force, these load cells measure a pushing force. Compression load cells are therefore under the object to be measured.
Load cells are very versatile and can be used in a number of ways. Compression load cells can calculate the relative change in resistance. Compression load cells have a Wheatstone bridge circuit that allows it to keep track of relative changes accurately.
Compression load cells are also made with high quality materials. They are durable and resistant to wear and tear, however, it’s still important to keep the base plate pristine for accurate readings. Good quality compression load cells typically have a hardened cover for greater protection.
Load Cell Design
Compression load cells are compact so that they can be used in smaller spaces. Despite their size, they can handle high capacity loads and reads accurately. Compression load cells by Contact Instruments, for example can measure a direct load of 150,000 lbs.
Load Cell Applications
Compression load cells are versatile and can be used in a number of ways. They are used in oil rigging plants including wireline, power tongs, bulk bin, cement bin, and wireline anchors. They can also be used in industries where products are solely sold by weight. Compression load cells can be used to weigh tanks and in plant engineering as well. These cells are able to quickly process and measure load, enhancing productivity and keeping costs low.
Contact Instruments’ compression load cells are versatile since they are made from the highest quality materials. They can be used in the harshest conditions and last many year. Over the years these hydraulic load cells have proven their durability and are reliable since little to no maintenance is required. Our compression load cells come in seven sensor options.
Types of Load Cells and Force Sensors
As the most common type of force sensors, load cells 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 confined 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 cells function 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.
Other Load Cells
Above are the three 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.
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 offers premium quality load cells and force sensors. Moreover, we also provide custom cables, overmolded cable assemblies, and other oil rig instrumentation at competitive rates!