Measuring techniques for continuous level measurement

In continuous level measurement, the level of a medium in a tank or silo is detected with the help of different measuring methods and converted into an electronic signal. The level signal is either displayed directly on site or incorporated into a process control or management system.

Typical applications for continuous level measurement are process tanks, storage tanks or silos in the process industry.

The measured media are:

• liquids
• pastes
• powders
• bulk solids

Measuring principles for pressure measurement

Pressure measuring techniques can be used to measure not only process or differential pressure, but also level, volume, density or mass flow in all areas of process technology.

The measuring ranges of pressure transmitters start at a few mbar and extend to extreme pressures up to 1,000 bar. Different measuring cells are used in these pressure instruments.

VEGA pressure transmitters deliver high-precision readings in

• gases
• vapours
• liquids

Measuring technique for flow rate measurement

Flow rate measuring instruments measure the amount of substance that flows through a pipe cross-section per time unit. The measured quantity is outputted as mass or volume. Typical flow rate applications measure gases, vapours and aggressive or viscous liquids in pipelines as well as bulk solids on conveyor belts.

VEGA uses two different physical measuring principles for flow rate measurement:

• Differential pressure
• Radiometric

Measuring techniques for point level detection

In point level detection, a point level switch detects when a certain predefined level is reached. Such a device is employed when it is not necessary to measure every possible intermediate level, as is the case with continuous level measurement. A switching command starts or stops filling equipment such as conveyors or pumps. Point level switches outputting a binary signal can be integrated into a process control system.

Point level detection systems can be used in liquids, pastes, powders or coarse bulk solids.

Typical applications for level switches are:

• minimum or maximum detection
• leak detection
• overfill protection

in process tanks, storage tanks, silos and pipelines.

Measuring techniques for density measurement

The proportion of solid matter in a liquid is determined with the help of density measurement.

Typical applications in the process industry are the measurement of acid and lye concentrations, the mixture density of abrasive or sticky liquids and the solid matter content of sludges and slurries.

VEGA uses two different physical measuring principles for density measurement

• Differential pressure
• Radiometric

Instruments and software for signal processing and sensor adjustment

Industrial processes are highly automated nowadays. To ensure smooth operation, measuring instruments are employed to deliver a steady flow of up-to-date, objective information about the process to the control technology. Various hardware components as well as signal conditioning software process and integrate the measurement data.

They convert the analogue or digital signals from the measuring instruments into information, i.e. measured values, that are displayed on indicating instruments or fed directly into the control system.