VEGABAR, VEGAWELL, VEGADIF: Hydrostatic level measurement
How does hydrostatic level measurement work?
Hydrostatic pressure refers to the mass of a stationary liquid at a given point of measurement. As level increases inside a tank, the hydrostatic pressure increases proportionally. Thus, the higher the hydrostatic pressure measurement, the higher the liquid level measurement.
Making this measurement requires installing a pressure transmitter on a tank so the instrument’s measuring cell is submersed in liquid. The transmitter measures hydrostatic pressure and converts it to a level measurement reading based on the equation below.
Height (Level) = Hydrostatic pressure/(Liquid density * Specific gravity)
What are the advantages of hydrostatic level transmitters?Hydrostatics have been in use in the process control industry for a long, long time. They are field-proven and familiar to users in many industries. Hydrostatic level instruments provide a reliable, accurate liquid level measurement even through adverse conditions in a tank such as foam, agitation, and obstructions. Users do not have to consider dielectric constant, and the instruments are easy to calibrate.
While hydrostatic level measurement is a process automation mainstay, the sophistication of the sensors is constantly increasing. Users are now empowered to choose the best measurement cell material for their process. For example, VEGA offers dry ceramic measuring cells for abrasion resistance and durability as well as metallic measuring cells allow for reliable measurement of many different liquids.
What are common applications for level measurement using hydrostatic pressure sensors?
Application examples for hydrostatic level measurement
Level control in a pumping stationTo the application
Process water tank
Level measurement in the process water tankTo the application
Ballast water tanks
Level measurement in the forepeak, wing and double bottom tanks with ballast waterTo the application
Level measurement in the diesel tankTo the application
In hydrostatic level measurement, the measuring cell of the pressure transmitter detects the tiniest changes in hydrostatic pressure, which increases or decreases depending on the level. The acting pressure is converted into an electrical signal and converted into an output signal by the integrated electronics.
Submersible pressure transmitter = VEGABAR 86/87, VEGAWELL 52. Compact version = VEGABAR 81, 82, 83 Chemical seal = VEGABAR 81 Ceramic measuring cell = VEGABAR 82, 86, VEGAWELL 52 Metallic measuring cell = VEGABAR 83, 87
The submersible pressure transmitters can be freely suspended above the well or channel or mounted in a process fitting on the vessel. The compact versions are installed directly on the vessel. This can be done from below or from the side. A variety of process fittings and seals allow for a secure installation.
The instrument is connected with standard two-wire cable.
As soon as a plausible measured value is found, the corresponding current is output on the signal line. The value corresponds to the current filling level, based on a density value of 1 g/cm³.