May 31, 2021 Loadcell
Load cells are used to measure weight. They are a part of our daily life. Of course, they are usually not immediately recognizable because they are usually hidden in the inner workings of instruments.
Load cells generally consist of a spring element on which strain gauges have been placed. The spring element is usually made of steel or aluminium. That means it is very sturdy, but also minimally elastic. As the name “spring element” suggests, the steel is slightly deformed under load, but then returns to its starting position, responding elastically to every load. These extremely small changes can be acquired with strain gauges. Then finally the deformation of the strain gauge is interpreted by analysis electronics to determine the weight.
They are electrical conductors firmly attached to a film in a meandering pattern. When this film is pulled, it – and the conductors – get longer. When it is contracted, it gets shorter. This causes the resistance in the electrical conductors to change. The strain can be determined on this basis, as resistance increases with strain and diminishes with contraction.
The strain gauges are firmly attached to the spring element, and therefore undergo the same movements it does. These strain gauges are arranged in what is called a bridge circuit, or more precisely a Wheatstone bridge circuit. This means that four SGs are connected “in a ring” and the measuring grid of the force being measured is aligned accordingly.
If an object is placed on the load cell or suspended from it, the object's weight can be determined. The intended load for a load cell is always aligned in the direction of the centre of the earth, in other words in the direction of gravity. Only that force component of the load should be acquired. That is not the case for force sensors, which are similar in design, and are also frequently specified as "load cells": They are usually designed to acquire loads that occur in all directions. The direction of the earth's gravitational force is not relevant to how they are installed.
Types of load cells
There are different types of load cells for different applications. Commonly used ones include:
- Single point load cells: a load cell is located under a platform that is loaded with weight from above
- Bending beam load cells: several load cells are positioned under a steel structure and are loaded with weight from above
- Compressive force load cells: several high-capacity load cells are positioned under a steel structure that is loaded with weight from above
- Tensile load cells: a weight is suspended from one or more load cells
Load cells can also be categorized based on the type of signal transmission: Digital load cells have built-in electronics used to process the measurement results and present them in a prepared format. For analogue load cells, an additional device – a measuring amplifier – is required.
Loadcell is available through Quick Time Engineering Inc.
Quick Time Engineering Inc is an international company with offices and distribution networks in the USA, Hong Kong, Europe and Malaysia.
In its 20 years of operation since 1998, Quick Time Engineering Inc had emerged from a local engineering company with a single staff that provided solutions in factory automation to become nowadays a company that serves the Oil & Gas industries, EPC contractors, System Integrators and other industrial automation and process control companies worldwide. Customers from over 50 countries worldwide trust us with their need for process control instruments and industrial automation products.
For more information about Quick Time Engineering Inc, visit www.quicktimeonline.com or email enquiry@quicktimeonline.com
