Measuring the level of solids has unique challenges with an uneven surface in many cases. In an Emerson Exchange Americas Virtual Series presentation, Emerson’s Regina Nemeth and Lovisa Rogestedt discussed:
…how the complete Rosemount Solids Level Portfolio, including both continuous and point level detection, meets your process requirements and provides a reliable and safe solution for your applications.
Lovisa opened showing the portfolio of solids level measurement devices that they would be discussing. They address several solids measurement applications from continuous measurement to point level measurement for alerts and alarms.
For powder applications, Regina noted that the environment can be very dusty. It can also coat all surfaces including the level measurement device which can affect the accuracy of the measurement. The surface can be unlevel and bumpy with measurements taken on slopes. She recommended the Rosemount 5408 non-contacting radar for these measurements. It’s important that the surface can reflect the radar back to the device. The dust can coat the radar antenna. An air purging system can be used to keep the surfaces clean. A parabolic antenna has a built-in purging system. The parabolic antenna can be angled for measurements on slopes and other difficult conditions.
Diagnostics can determine if the antenna is becoming coated or other conditions that affect the radar signal. This diagnostic helps to optimize maintenance and measurement reliability.
Lovisa described various point level measurement devices for various applications requiring notifications based on reaching a certain level. The Rosemount 2555 capacitance switch has active shield technology to still measure accurately even when the capacitance probe is coated. It has the advantage of no moving parts, high pressure rated, and suitability for hygienic applications.
Rotating paddle technology in the Rosemount 2501 solids level switch can handle extreme temperature applications, withstands heavy loads and is suitable for full, demand or empty detection for all bulk media in all types of vessel.
For fluidized powders, the Rosemount 2511 and 2521 vibrating fork switches is the most sensitive of the portfolio of solids measurement devices. The 2511 is suitable for fine-grained and powdered medias in storage and process vessels. The 2521 is suitable for fine-grained and powdered media in storage and process vessels where high sensitivity is needed.
Lovisa described applications with larger solids particles and heavy bulk densities and dust. The Rosemount 5408 non-contacting radar is a great fit for these applications. The Rosemount 2535 vibrating rod solids level switch is good where solids particles could lodge in the measurement switches with vibrating forks.
For difficult applications such as tall thin silos, irregular bumpy surfaces, Regina noted that Rosemount 5300 guided wave radar series is a very good fit. It provides continuous level measurement over the full range. If you need just a point level reading that don’t have stickiness issues, the vibrating measurements provide a good solution.
The vibrating switches are well suited for simple application. The rotating paddle and capacitance switch for more challenging applications. For continuous measurements the non-contacting and guided wave radar instruments are a good choice.
Regina referenced a bulk solids level measurement application guide to help you find the best measurement devices for your solids applications.
Visit the Solids Level Measurement section on Emerson.com for more on these technologies and the best fit for your application. Read this article to learn how to utilize non-contacting radar level measurement in pulp mills.