The effect of measuring symmetric and asymmetric capillary tube pressure
Important points in choosing and installing a pressure difference level gauge with a flood diaphragm that we need to know
- Temperature effect:
If the ambient temperature rises, capillary V tends to exert force on the DP flood diaphragm (both sides). If both capillaries have the same properties (volume, capillary thickness , fluid filling, and length) are the same, all the resulting forces on the DP flood diaphragm will be zero (Figure DP flood diaphragm position below).
2. Hydrostatic pressure:
The shape of the hydrostatic pressure is below P = ρ × g × D (where ρ and g are constant). To increase the ambient temperature, the density ρ decreases. This means that the hydrostatic pressure P is also reduced. This creates a high force (against the force of gravity). The resulting (final) DP flood diaphragm position is shown in the red figure below.