Filling level

The filling quantity in the fermenter of a biogas plant can be determined using the expansion of the gas tank. This is important in order to assure a constant gas flow to the combustion engine. Draw-wire sensors which are clamped above the film are used for this. The sensor itself is located in the generator building. If the film rises, a displacement change of the sensor is registered.

In falling film reactors used by the chemicals industry, the geometrical dimensions of the reactor metal sheet are measured using confocal sensors. The filling level of the liquid is also measured during this test. The channels have dimensions of 200µm depth and a width of 400µm. The advantages of using a compact beam path are fully exploited in this application example.

To obtain a homogeneous oxide-free aluminium cast, the aluminium level in the open mould must be kept constant to within 1 mm or better. A constant level is achieved by controlled tilting of the furnace. The current level is measured and monitored from above with air-cooled eddy current sensors. A temperature-stable output signal and the high operating temperature of the eddy current sensors are particularly significant in this measurement.

A filling level measurement situation can arise with a liquid substance as well as with dry, bulky goods. The precise measurement of liquid levels is difficult to achieve, nevertheless, the confocal measuring technique is a suitable solution for this problem. Light is also reflected on the surface of liquids and thus provides a reliable result. Filling levels of dry bulk materials are easier to measure due to the surfaces. The ILR Time-of-Flight sensors are suitable for deep containers. Laser sensors from the optoNCDT group are available for shorter sections.

Precisely measuring the level of liquids is known in measuring technology as difficult to achieve. Nevertheless, the confocal measuring technique is suitable as a very good solution for this problem. Light is also reflected on the surface of liquids and thus provides a reliable result.

After the oil has been filled by a dispenser machine, an ILD1420-200 measures the level. If this is less than 4 mm or if the sensor was not filled at all due to production errors, it is evaluated as NOK and sorted from the production line. Since the oil temperature sensors have a very narrow inner diameter of only 4 mm and a depth to be tested of 28 mm, a measuring range of 200 mm is used. This ensures that the laser can reliably measure into the filling tube.

In aluminium casting plants or foundries, the cast is poured into shape to form small bars, known as pig irons. The charging level in the forming process is critical in ensuring consistent weight of the pigs. Using a special non-contact measuring device, the depth of fill is recorded. For these applications, an Austrian system builder uses laser scanners. 

For smooth production and logistics processes, precise quantity measurements at storage locations for bulk goods or plastic granulates, for example, is a decisive factor. In order to avoid production downtime due to missing material, the levels of the storage silos must therefore be reliably and automatically detected. Laser distance sensors from Micro-Epsilon, which are specially designed for these applications are increasingly used. Here, the optoNCDT ILR2250-100 sensors are applied. They are mounted on the lid of the silo and measure continuously towards the silo bottom. The laser distance sensors detect exactly the distance between sensor and bulk material or granulate.

For this measurement task, the barrel stands on the platform of the hydraulic press. There is one hydraulic cylinder each on the left and right. Both cylinders are connected to each other by a cross beam. In the middle of this is a piston which is pressed into the barrel. A wireSENSOR WDS-P60 draw-wire sensor is mounted on the outside of the crossbar.

The wire shortens and the sensor thus measures the decreasing lifting height of the cylinder via the potentiometer. Subsequently, the analog output signal is transferred to a controller.

In microbiology, cell cultures are used for the analysis of so-called agar plates. The agar plate should be consistently as high as possible - this is a critical factor for later evaluation of the cell colony cultivated on it. For the inspection of the fill level, the metrological control of the agar plate during the production process is invaluable. This measurement task is solved by using a three-channel version of the capaNCDT6220 capacitive measurement system.

The capacitors must be dipped into a bath of solvent during the capacitor production. In doing so, it is important that the blanks only have a specified immersion depth. Confocal chromatic sensors are used for measuring the level in the bath. They measure with high precision and without contact on directly reflecting liquids.

A filling level measurement situation can arise with a liquid substance as well as with dry, bulky goods. The precise measurement of liquid levels is difficult to achieve, nevertheless, the confocal measuring technique is a suitable solution for this problem. Light is also reflected on the surface of liquids and thus provides a reliable result. Filling levels of dry bulk materials are easier to measure due to the surfaces. The ILR Time-of-Flight sensors are suitable for deep containers. Laser sensors from the optoNCDT group are available for shorter sections.