Load Cells vs. Strain Gauge: A load cell is a transducer that converts mass and pressure force into a measurable electrical output. Load cells are one such tool that is commonly used to measure weight. When force is applied to a load cell, it converts the force into an electrical signal. Load cells are also known as transducers. You can find load cells everywhere, even in nearby supermarkets to weigh your items. Load cells are available in many different shapes, types, and sizes. Many manufacturers are inventing different types of load cells as we speak. In a load cell, the areas and structures are designed to compress when a linear force is applied. The output is usually in millivolts and must be amplified in order to read it. Load cells are available in many different configurations and standards depending on the environment. Some varieties depend on calibration to measure charge displacement. A true load cell will always work in the direction of gravity, but most drop cells are designed to measure weight from all directions. Let’s look at the differences between load cells and strain gauge in detail in this article.
Load Cells vs Strain Gauge
Let’s look at the differences between the Load Cells vs Strain Gauge in detail.
Types Of Load Cells
- Compression load cells
- Bending beam load cells
- Hydraulic load cells
- Capacitive load cells
- Pneumatic load cells
- Shear beam load cells
Compression Load Cells
Load Cells vs Strain Gauge: A compression load cell is one of the major categories or types of load cell commonly found within the weighing industry. The actual internal workings of a compression load cell can be quite varied. They can be based on shear, bending, ring-torsion or column measurements. Compression load cells, like all other modern load cells, are essentially transducers that convert force or weight into an electrical signal. Compression load cells can be integral to applications in which the cell is required to carry the load from tension to compression and from compression to tension.
Bending Beam Load Cells
Bending beam load cells are designed so that certain parts of the load cell body bend or curve in response to an applied load. They tend to offer high amounts of strain or flex at relatively low forces, which suits them for lower capacity weight. The beam type load cell family, sometimes known as a bending load cell, tend to be the most commonly used in filling machinery, industrial floor scales, tank and silo weighing.
Hydraulic Load Cells
Load Cells vs Strain Gauge: Hydraulic load cells convert a load to hydraulic pressure. The measured load is applied to a platform attached to a piston. The piston sits in a closed chamber filled with fluid. The change in liquid pressure is directly sent to the force applied by the load. This liquid pressure is readable through an attached bourdon tube pressure gauge. Hydraulic load cells can typically measure up to 5MN and have an accuracy of about 0.25 to 1.0 percent.
Capacitive Load Cells
Capacitive load cells operate on the ability of a material or system to store a charge. They consist of two parallel plates with a gap between them. An electric current is supplied to the plates until a stable charge forms on each one with a positive charge and the other negative charge. These charges create output which is converted into load measurement. Capacitive load cells are highly sensitive which makes them a good choice for food and medical weighing industries.
Pneumatic Load Cells
Load Cells vs Strain Gauge: A pneumatic load cell is a type of force measurement device that works using the air pressure. It is designed to measure and convert mechanical force or weight into a pneumatic signal, which can be used to control and monitor processes in various industrial applications. The advantage of Pneumatic load cells are it can be used in situations where usage of electrical load cells are a risk due to explosive environments like chemical factories etc., as they are safe and do not generate sparks. Due to their simple design pneumatic load cells requires less maintenance than other types of load cells.
Shear Beam Load Cells
Shear beam load cells are suitable for weighing applications of medium or large capacity. They can be used to construct multi-sensor scales, for weighing tanks, or for onboard weighing on vehicles. These type of load cells are commonly used in Shear beam load cells are widely used where operators need to measure compressive forces. The core component of a shear beam load cell is a spring element. This element is a piece of metal that is elastically deformed under load and recovers the moment the load is removed. The strain is converted into signals and the load is measured.
A strain gauge is used to measure strain. Then a force is applied, a strain gauge is used as a sensor for measuring variations in resistance, then converting those changes in electrical resistance at last converting to measurement. A strain gauge always consists of a backing layer and a grid made of alloy. The backing foil will be connected to a structure or element from which the strain needs to be measured.
Types Of Strain Gauge
- Linear strain gauge
- Shear strain gauge
Linear Strain Gauge
Linear strain gauges measure strain in one direction. As a result, they have the simplest construction and the lowest cost. This makes them suitable for general use, such as load testing, fatigue testing, and structural integrity monitoring.
Shear Strain Gauge
Shear strain gauges have 2 measuring grids arranged at a 90° degree offset from each other. Typical applications for these strain gauges include measurements on torsion bars and determining shear stresses as they occur in shear beams in the area of neutral fibers.
FAQs – Load Cells vs Strain Gauge
Q. What is a strain gauge?
It transforms force, pressure, tension, weight, etc. into a change in electrical resistance that can subsequently be measured. A strain gauge is a sensor whose resistance fluctuates with applied force. Stress and strain happen when outside forces are applied to a stationary item.
Q. Where do strain gauges get their use?
The torque that a motor, turbine, or engine applies to fans, generators, wheels, or propellers is measured using strain gauges. Power plants, ships, refineries, autos, and general industry all use this equipment. By measuring the strain and rotational speed on a shaft, power is determined.
Q. What use does surface gauge serve?
One of the most used marking instruments is the surface gauge, which is used for drawing lines perpendicular to a datum surface. assessing the height and parallelism of jobs while aligning them parallel to a datum surface.