in nearly all industrial and commercial tanking systems, tank levels must be continually monitored. To prevent under or overfilling, the level within a tank is checked and controlled by using a combination of level sensors, gauges and indicators. These are mounted at various points in the tank, depending on the medium selected, the size of the tanks, the temperature and the density of materials used.
Continuous Measurement using Bypass Level Indicators
For this type of application, bypass level indicators are often used for continuous measurement, display and monitoring of liquid levels. The bypass tube is attached onto the side wall of the vessel. According to the law of communicating tubes the level in the bypass tube equals the level in the vessel, therefore producing an accurate, timely measurement.
Even at long distances, liquid levels in containers or tanks are clearly visible with the bypass level indicator, NBK from KOBOLD. The measurement system consists of a liquid-density adjusted float moving in an external bypass tube that extends to the full height of the container and is flanged at both ends. To achieve a clearly visible level indication, a magnet in the float causes two-coloured rollers to rotate by 180° as the float moves up or down with the liquid level. The red column of rollers below the float corresponds to the liquid level. Above the float, the column is white. With a single device, levels up to 6 m can be measured. In case of much higher containers the measurement range can be extended by versions with two or more sections. Models equipped with transmitters or contact sensors can output the level data as 4-20mA signals or send switching pulses to indicate threshold events. The protection rating of the electrical attachment is IP65 or better.
Level You Can Rely On
Successful continuous measurement using bypass level indicator NBK-M was delivered for a manufacturer who required local visual indication of the liquid condensate level in separator stations for the supply of steam and condensate systems for the paper industry. We have also seen examples of the robust NBK level indicators being installed on ships and submarines to provide continuous tank level measurement.
Bypass level indicators remain an accurate way to measure the levels of water, fuel, various chemicals, and oil. KOBOLD devices are manufactured to withstand viscosity up to 200 mm2/s and depending on the model, pressures up to PN 100 and temperatures up to 400 °C can be measured. For hazardous areas, ATEX-certified versions are available.
Level of different mediums can also be determined by either differential pressure, hydrostatic sensor, ultrasonic sensor, pneumatic level measurement, float switch or by pressure measurement.
Alternative Level Control using Float switches
The use of modern float switches can be a good and simple solution to regulate the flow of fluids or to provide optimized refill requirements. It allows many areas to be easily automated and thus managed more quickly and easily. This applies to both liquids and bulk material, which can also be monitored by means of various level sensors.
Magnetic level switch are mainly used to measure the level of liquids in many areas. However, if this is not possible because of the nature of medium, for example, if the medium is so contaminated that it could hinder the magnetic level switch, float switches are often used. In general, two float switches are used, one operates as a minimum level switch and other as a maximum level switch.
Thus, level control and level determination can be carried out without problems via such float switches. Anyone who needs a direct overview of the existing residual quantity of liquid will generally rely on finer level sensors, which allow a direct overview of the amount of remaining liquid by means of pressure, ultrasonic or radar level measurement principles.
These level sensors offer two different variations. On one hand, the results can be read directly by means of a measuring transmitter at the filling level sensor. On the other hand, the signals from the sensors can be transmitted to the various output systems via BUS interface and can be retrieved there. This system of continuous level measurement is of huge advantage. In this way, safety-related changes in level can be determined more quickly and can be reacted accordingly.
Particularly in the case of liquids for cooling circuits, continuous level measurements are frequently used. In closed containers and circulators, both level and pressure play an important role. By means of a comprehensive level measurement and a control of the pressure in relation, reliable information about the system and its state can be quickly made. A suitable level indicator or a correspondingly introduced level sensor can not only transmit this data but also display it directly in the working area.
Different Methods of Level Detection
Level meters in the Kobold portfolio are based on different measuring systems and measuring principles and offer a high degree of flexibility in their application. Depending on the liquid used and its density, the place of application and the size of the filling quantities, different systems can be used. While float switches and level switches can be used in many areas due to their simple adaptability, a more comprehensive measurement of the filling levels and level values is necessary in other areas. Ultrasonic or radar level switches, for example, can be used here since they can achieve more precise results with significantly smaller dimensions.
Not only liquids, such as water, must be monitored and controlled using a level meter, levels of bulk material in silos or similar systems must also be checked - for example during filling. High-quality rotary level monitors or capacitive level sensors can take over the monitoring and control and stop the filling when the desired level is reached.
A Solution at your Fingertips
For every type of level measurement, Kobold offers a range of suitable level gauges and level indicators, which can be easily integrated into various tanks and production systems. In this way, the filling level of plants, tanks and silos can be either continuously or in samples checked.