Advantages and challenges of measuring liquid level with DP transmitter

Advantages and challenges of measuring liquid level with DP transmitter

The DP transmitter calculates the liquid level by measuring the pressure difference between the liquid phase and the gas phase of the fluid in the closed tank. In order to make accurate calculations, important factors include: the geometry of the container (horizontal or vertical, various lid and bottom shapes, etc.)
●The specific gravity of the medium
●Hydrostatic pressure
The distance between point H and point L in the storage tank must be much longer than that in the pipeline, so oil pipes must be used to bridge this distance. However, not only pipes of any size can be used. In order to make accurate measurements, these small pipes (actually capillaries) must be very thin and limited in volume so that they can transport the medium without changing the pressure.
However, the use of capillary will bring a series of challenges. In a closed system, the pressure of the gas is proportional to the temperature. This is Guy: Lusak's Law. The measurement solution connected at the measurement point of the larger pipeline is sensitive to temperature. In very bad cases, drastic fluctuations may lead to erroneous measurement values. The measurement solution connected to the measuring point is sensitive to temperature. In very bad cases, drastic fluctuations may lead to erroneous measurement values.