In non-contact level measurement, ultrasonic and open-path radar sensors are well known in the industry. However, in recent years, laser level measurement has been gaining popularity in several applications and have been developed more than the other technologies due to its versatility and ease-of-use. Laser transmitters send short pulses and measure the time of flight of pulses that are reflected from a surface to determine distance. The laser has a very narrow field of view (<0.3°), so it only detects returns from the surface to be measured and is not impacted by surrounding objects. This ability of laser level has been used with enormous success in the plastic industry applications due to its narrow beam and ability to measure right down to the bottom of the silo or vessels.
Please find here the link to application note related to ABB’s LLT100 for plastics industry.
Level measurement of silos in plastic industry
ABB’s laser transmitters innovative technology makes possible level measurement in the plastic industry. The demand for plastic is growing as it is increasingly being used as a substitute for metals or other materials in the automotive, construction, electrical and electronic industries. Typically, plastic manufacturers are large petrochemical and chemical companies that produce and supply raw plastic material, mostly in the form of pellets, to the rest of the supply chain. These companies value automation solutions and live inventory reporting, and they have used level measurement for storage or blending silos. Plastic product manufacturers also use level measurements in storage silos or day bins for inventory management.
The ability of laser level has been used with enormous success in the plastic industry applications due to its narrow beam and ability to measure right down to the bottom of the silo or vessels.
Figure 01: Narrow beam emitted by the LLT100 Laser Level Transmitter
In addition, the total cost ownership of such solutions is critical for this industry with global & local competitions increasing ever since globalization expanded to all markets. This means that the installation, commissioning and easy maintenance of level measuring systems are also key aspects on selection of a product & technology.
Another important advantage of using lasers in these applications is that silos of day bins are usually identical. Contrary to other technologies, laser levels only need to be configured for the first silo. This configuration then can be used for all remaining silos, making installation and commissioning easier, faster and less costly. In addition to our LLT100 laser level solution, ABB also offers a complete turnkey solution with PLC control panel, displays, I/Os, customized user interface and more.
Benefits of Laser Level Transmitter
- The only non-contact technology permitting to measure way down to bottom of conical vessel. As compared to ultrasonic and microwave waves, the wavelength of light waves is very short, due to which they experience no virtual beam divergence, hence a laser beam can be targeted on a point without facing any intervention from the nearby entities. Thanks to narrow beam of 0.3 degree divergence, can be directed through spaces as small as 2 in.
- Plastic pellets will not stick to the device and break moving parts leading to repetitive maintenance as is the case for contact technologies.
- Strong laser beam reflection from plastics in contrast to radar waves.
- Simple and easy to use, easy to install and reliable - No echo mapping required.
- Works with low dielectric constant materials, not affected by local structures or changes in the properties of the material to be measured.
- Works with low dielectric constant materials.
- Typical environment is not dusty, so no issue for laser beam.
- Can be installed very close to the wall and is unaffected by internal structures or vessel shape.
- The laser radiation propagates through the medium at the speed of light. This means that very high update rates are achievable, with none of the ‘lock-in’ problems that can be experienced when using ultrasonic instruments.
Laser level transmitters from ABB
ABB is one of the world’s leading suppliers of process monitoring equipment for industrial applications. Our Laser Level Transmitters have demonstrated the unique potential for safe and reliable measurement in demanding areas of application, With thousands of installations over the last decade, ABB’s LLT100 laser level transmitters have enjoyed excellent success in the plastic industry applications.
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