Level sensors for level measurement
Levels must be measured in almost all industries. Depending on the application, you want to continuously measure the level or occasionally receive a notification that states the quantity or volume: is there enough liquid in the tank? Is the silo sufficiently solid?
Level switches and level sensors
Analogue level measurement
Sensors for continuous level measurement provide constant information about the level of the substance present (level sensors). Level detection sensors provide information on predefined levels when not measuring any arbitrary level. Something that is the case with continuous level measurement (level switches). Level detection sensors are ideal for detecting minimum and maximum levels, leak detection and overfill protection.
Level sensors for level detection
Min-max level detection
By detecting a min-max level in a silo, a pump control can be performed by applying two level sensors. One level sensor for the minimum level and one for the maximum level. When the level reaches the minimum point, the digital output switches the filling system of new liquid. As soon as the tank reaches the maximum level, the supply stops. This not only prevents malfunctions in the process, for example when a storage tank becomes empty or a pan boils dry, but also prevents production loss and damage due to the overflow of a storage tank or reservoir.
Measuring principles for level measurement:
- Capacitive level measurement
- Ultrasonic level measurement
- Runtime measurement with laser (TOF principle)
||Solids||Transparant|| Not transparent
||Sticky fabrics and foam|
| Capacitive level measurement
||Yes||Depending on material||Yes||Yes||Yes|
|Ultrasonic level measurement||Yes||Yes||Yes||Yes||No|
|Runtime measurement with laser (TOF-principle)||Yes||Yes||No||Yes||No|
Capacitive level sensor for analogue level measurement
Capacitive level sensors continuously measure the level of the liquid present. The KFX TrueLevel capacitive level sensor from Rechner Sensors features a probe and is set with an empty silo, tank or container that provides a linear analog output signal over the entire fill range of any medium in 4-20 mA or 0-10 V DC. The probe has a maximum length of 2 meters.
All electronics of the capacitive level sensor are integrated in the G1 "mounting head. Due to the patented three-electrode concept, each sensor has a reference area for compensating the different liquids (even at low values such as ≥ Ɛr 1.2). So there is only one setting required to commission a new level sensor.
Rechner's TrueLevel KFX level sensor is ideal for applications where different liquids are processed with one machine. Read more about capative sensors.
Capacitive sensor for level measurement of adhensive and viscous substances
The LevelMaster sensors from Rechner Sensors have been developed for level measurement of liquid and viscous substances that are adhesive and / or conductive. The 26-series capacitive sensors from Rechner Sensors are High Performance (HP) sensors with unique characteristics in size and shape of the sensor.
26 series capacitive level sensors
The 26 Series sensors perform better than any sensor when it comes to ignoring material build-up. With no moving parts, the 26 Series sensor differs from other level sensors such as: vibrating rods, tuning forks and paddle wheels that are prone to cavitation, bridging and material buildup jamming. The 26 series has two models: 1 model for high dielectric materials (such as ketchup and bread batter) and 1 model for everything else (eg grains, flour and alcohol products).
In addition to the new analogue output option, it is also possible to detect signs of contamination so that a cleaning process can be initiated. Another application option is a representation of the change in the dielectric constant (DC) of the product to be monitored for quality control. For quality control purposes, the empirically determined starting values can be checked and analyzed using, for example, a PLC. Read more about analogue sensor for level measurement.
Continuous level measurement of solids and liquids with ultrasonic level sensor
Ultrasonic level measurement
The level measurement is not affected by the dielectric constant, density or humidity. Typical for ultrasonic level sensors: continuous, contactless and maintenance-free level measurement of liquids, pastes, sludge and powdery, but also coarse, bulk materials. The accuracy and performance of ultrasonic level sensors decrease in foaming and vacuum applications. Read more about ultrasonic sensors
Level detection with runtime measurement
Laser sensors that determine the level in tanks and silos based on a light-travel time measurement are ideally suited for level measurement of non-transparent liquids, bulk solids and varying materials. In addition, they are less suitable for the detection of foaming, sticky and transparent liquids. These substances cause dispersion and lens contamination, which significantly reduces the reliability of the measurement. SensoPart's F 55 series photocells are ideal for level control. Control of two filling levels with two switching outputs can be set independently.
Features level detection with smooth-running time measurement:
- Contactless level measurement
- Suitable for bulk goods, solids and powders
- Not suitable for sticky, foaming and transparent liquids
Capacitive level measurement of additives
Detect powder or liquid level
But how do you know what the powder or liquid level is in the printer or the additive? Rechner Sensors has the solution with capacitive level sensors that can excellently detect the conductive powders and sticky liquids. Read more about level measurement of additives for 3D printers.
Level control with sensor for minimum and maximum level
Peanuts are supplied from a silo and placed in the packaging. A TOF sensor checks the filling level in the packaging by means of time-of-flight measurement. The level sensor switches at a minimum or maximum level.