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What to consider when choosing a level measuring instrument
Here’s how Fagerberg improves the everyday for the process industry.
Which level measuring instrument is right for your process? This depends on what you need to measure, the design of your tank or vessel and your measurement requirements.
Here, we guide you through the key factors to consider and provide an overview of different measurement technologies and where they are best suited.
1. Start with the medium
Whether you are measuring liquids, powders, porous fibres or granules is a good starting point. The properties of the medium, such as density, foam formation, dust, vapour and its ability to reflect the measuring signal, also influence which measurement principles can be used.
2. Continuous measurement or level monitoring?
Do you need to know how much material is in a tank, or simply when the level reaches a certain point? Continuous level measuring instruments monitor the level over time, while level switches are used for applications such as overfill protection, dry-run protection and high- or low-level alarms.
3. Consider your process conditions
Tank height and design, measuring range, mounting position, process connections, temperature and pressure all influence the choice of instrument. Whether the tank is open or pressurised, and whether it contains agitators or other obstructions, can also affect which technology is most suitable.
4. Non-contact or contact measurement?
Radar and ultrasonic technologies allow level measurement without contact with the medium. Other measurement principles, such as guided wave radar (TDR) and capacitive level measurement, use a rod or cable extending into the vessel. The most suitable solution depends on the medium, process conditions and installation.
5. Consider installation and process conditions
Foam, vapour, condensation and dust can affect the measurement result. Sensor positioning and any obstructions inside the tank also need to be considered. Corrosive media, high temperatures and hazardous areas may place additional demands on materials and instrument design.
6. Which type of level measurement is right for your application?
A brief overview of our different product categories.
Capacitive level measuring instruments
Use changes in capacitance to measure or monitor the level. Suitable for both liquids and solids, depending on the instrument design and the properties of the medium.
Level gauges
Provide a local, visual indication of liquid level in tanks and process vessels. Magnetic level gauges are an option when the level needs to be read directly at the vessel.
Level switches
Detect when the medium reaches a specified level and are used for alarms, pump control and overfill protection. Available with different measurement principles, including vibrating, capacitive and float-based technologies.
Radar / TDR
Radar technology is used for continuous level measurement of both liquids and solids. Non-contact radar measures the level from above without touching the medium and is suitable for a wide range of applications. Guided wave radar (TDR) uses a rod or cable to guide the measuring signal through the vessel. This technology can be suitable for applications involving vapour, foam or dust, and can also be used to measure the interface between two liquids.
Ultrasonic level measurement
Uses sound pulses for continuous, non-contact level measurement. Suitable for open basins, wells and tanks operating at conditions close to atmospheric pressure.
No single measurement principle is suitable for every application. The best choice depends on the medium, vessel design and how the measurement will be used.