A load cell is a type of transducer, which is an instrument that converts signals from one form of energy to another. Load cells, in particular, work by measuring a type of force and then creating a directly proportional electrical signal. There are several types of load cells, including piezoelectric, hydraulic, pneumatic, and tension. This article will focus on the tension load cell, which is also referred to as a strain gauge load cell.
How Exactly Does a Tension Load Cell Work?
Every tension load cell contains a strain gauge, which is an instrument used to measure how much strain, or tension, is being placed on an object. To understand how a tension load cell works, a person must first understand the strain gauge.
Most strain gauges contain a flexible insulating backing which acts as the structural support for a metallic foil pattern. Using an adhesive-like cyanoacrylate, the strain gauge is attached to an object, in this case, a tension load cell.
The tension load cell measures the force being placed on it through the deformation of the strain gauge. As it becomes deformed, the foil inside also becomes deformed, and its electrical resistance changes. This change in resistance is typically measured by a Wheatstone bridge, which is an electrical circuit designed specifically for this purpose. An electrical signal proportional to the change in resistance is produced. This electrical signal, which is usually only several millivolts, has to be amplified before it can be used. This is required so that the force applied to the tension load cell can be calculated.
There is one last thing to note. A tension load cell can contain one, two, or four strain gauges. Most contain four strain gauges, because this delivers maximum sensitivity to the force being measured.
Where is a Tension Load Cell Used?
Tension load cells are the most common load cells used in industry. They have great resonance values, are particularly sturdy, and usually last a long time in application. Additionally, they have excellent accuracy levels, and their unit costs continue to reduce. Because of this, they are used to measure the tension in a variety of materials, machines, and processes.
One of the most common uses for the tension load cell is in commercial weighing scales. In fact, many will tell you that the load cell is the most important part of an electronic weighing scale. The tension load cell is especially ideal for crane scales, which measures weight by attaching the load to the crane hook. Crane scales are normally used for items that must be weighed when lifted. They are frequently attached to cranes or hoists as a safety measure to prevent overloading. Crane scales also provide accurate weight measurements “on the fly” as items are being moved by the crane.
