Hydrostatic and Submersible level transmitters Working principle
Hydrostatic and submersible level instruments use the head pressure of a fluid to infer level. It’s one of the oldest and most common methods around, and with good reason. Using pressure to measure level is a simple, reliable and for the most part cost effective solutions for a wide range of applications across many industries.
The equation to convert pressure (P) to level (L) is:
Thus, the equation for pressure (P) generated is:
𝑃 = 𝐿𝜌𝑔
L = level of fluid in metres above the sensor
P = pressure in kPa
ρ = density of the fluid in g/cm3
g = gravity, (Can be considered 9.81 m/s2 for most locations)
Example 1 - Level where pressure is known
1. Pressure (P) of 4.9 kPa
2. Fluid density (ρ) of 1 g/cm3
3. Gravity (g) at sea level = 9.81 m/s2
𝐿 =4.9/ (1 × 9.81) = 𝟎. 𝟓 𝒎𝒆𝒕𝒓𝒆
Example 2 – Pressure when level is known
1. Fluid level (L) is 0.5 metres
2. Fluid density of 1 g/cm3
3. Gravity at sea level = 9.81 m/s2
𝑃 = 0.5 × 1 × 9.81 = 𝟒. 𝟗 𝒌𝑷
1. Top mount hydrostatic level transmitter with a flexible insertion length.
2. Rigid top mount hydrostatic level transmitter for pressurised vessels.
3. Rigid top mount hydrostatic level transmitter.
4. Hygienic gauge pressure/level for pharmaceutical or sanitary applications.
5. Gauge pressure or level transmitter.
6. Differential pressure transmitter for pressurised vessels.
7. Remote differential pressure transmitter.
8. Submersible level transmitter.