Differential pressure sensors can be used to measure liquid level in a tank. Here we will explain how a DP sensor is used to measure liquid level.
Measurement & Instrumentation Guides
Guidance and reference articles for sourcing, setting up and using measurement equipment.
Calculating required pressure range for fuel tank level measurement
Using a pressure measurement instrument to measure fuel level is very common, however most are scaled in bar or psi pressure ranges, and if they do happen to be scaled in level units, they are typically water level based, such as mH2O or ftH2O.
Float Fluid Level Detection
Float activated switches for opening or closing electrical contacts at a preset fluid level.
Vibrating Tuning Fork Fluid Level Detection
Vibrating tuning fork switches for opening or closing electrical contacts at a preset fluid level.
Conductive Fluid Level Detection
Conductive sensing for detecting when a preset fluid level has been reached.
Capacitive Fluid Level Measurement
Capacitance method for measuring the level of a fluid.
Liquid Level Sensors
Device for measuring liquid level and converting it to an electrical signal to send to other instrumentation.
How do you measure the volume of a liquid using pressure
It is not possible to measure the volume directly, and unfortunately there is no such device as a volume sensor, however if you know the dimensions of the space filled with liquid, you can easily determine the volume.
Hydrostatic Liquid Level Sensors
Collection of resources for selecting and using a hydrostatic liquid level sensor.
How to determine milk tank level and volume from pressure
How do I convert the pressure reading to quantity of milk at bottom temperature which varies approx 10 deg C
cmH2O – Centimetres of Water Column at 4 deg C Pressure Unit
Centimeters of Water Column is a manometric unit used to relate a pressure reading to the height of fresh water at a temperature of 4 degC. 1 centimeter of water gauge equals 98.0665 pascals.
ftH2O – Feet of Water Column at 4 deg C Pressure Unit
Foot of Water Column is an American and English low value pressure unit
Hydrostatic Pressure
Hydrostatic pressure is the pressure that is generated by the weight of liquid above a measurement point, when the liquid is at rest.
mH2O – Metres of Water Gauge at 4 deg C Pressure Unit
Meters of water gauge or column is a metric unit for measuring liquid level. 1 metre of water column at 4 degrees Celsius equals 9806.65 pascals.
mmH2O – Millimetres of Water Column at 4 deg C Pressure Unit
Millimeters of Water Column is a low range metric pressure unit derived from the hydrostatic pressure of 1mm head of water at 4 degC.
Specific Gravity
Specific gravity is a comparison ratio between the density of a particular substance and the density of a reference substance.
Liquid Level Measurement
Questions and answers about liquid level measurement
Measuring the volume of liquid in a horizontal cylinder tank
We have a horizontal cylindrical type tank which has a diameter of 2 meter and a length of 7 meters. This tank is used for storage of chemicals.
Problem with zero drift when installing submersible pressure sensor
I‘m having a problem zeroing a submersible pressure sensor. Before placing it in the water, the zero offset is trimmed on the indicator, and then it is submerged to full range depth of 10 metres. During the first few minutes we notice that the full scale reading drifts by about 10mm in the negative direction […]
Difference between vented and non-vented water level measurement
A hydrostatic level probe typically uses pressure sensor to measure the water level. The main component of a pressure sensor is the sensing diaphragm which converts the difference in pressure between either side of the diaphragm into a measured signal. The front of the diaphragm measures the water level pressure (hydrostatic pressure) plus the barometric […]
Determining water tank volume using hydrostatic pressure
Can a pressure measurement device be used to measure the volume in a rainwater harvesting tank?
Converting non-vented depth readings & barometric pressure to true depth
I have level data from a non-vented transducer & barometric pressure data, how do I determine the true depth?
Using Hydrostatic Pressure Transducers for Measuring Fluid Level
There are a number of methods and technologies for measuring the level of a fluid with hydrostatic pressure transducers.
Are all IP68 Water Resistant Protection Ratings the same
It is often assumed that devices with an IP68 rating are suitable for immersing underwater for an indefinite period at any depth. Not all devices that are IP68 are intended to be continuously submerged, some only require a temporary rating to protect from occasional submersion. For example a pressure transmitter installed below ground level will […]
Determining the Signal Cable Length of a Suspended Liquid Level Transducer
Deciding the correct length of cable for a suspended IP68 transducer is an important part of specifying, if the cable is too short it is difficult and expensive to join two cables together and make the seal liquid tight. There are two separate parts of the installation that need to be considered to determine the […]
Why are Submersible applications so demanding of Pressure Transducers?
Placing a sensing device in a liquid is one of the most hostile environments to ensure a long reliable service life. The extra considerations for design engineers include: Keeping pressurised liquid out. Preventing condensation damage to the internal electronics. Corrosion protection for all the materials used in the transducer construction. Adequate protection from lightning surges […]
Considerations for monitoring Landfill Water Level
In recent years regulations for environmental control, health and safety issues have become much more stringent for existing and new landfill sites. The regulations encompass many considerations and some involve the measurement and control of water level in many positions around a waste disposal site. One application is ensuring contaminated water is contained within a […]
How does changes in Local Gravity affect Hydrostatic Pressure
The value of hydrostatic pressure for a fixed height column of fluid is directly proportional to the gravitational strength at a particular geographical location. Generally if the height above sea level is increased the hydrostatic pressure will decrease. Also since the world is wider at the equator than the poles the gravitational pull will increase […]
Improve the electrical termination of vented submersible pressure sensors
Submersible cable is more expensive because it has to be reinforced to support the sensor plus its own weight in deep holes without stretching which would lead to a change in sensor position and ultimately sensor calibration. A submersible cable also has a vent tube running through it to allow gauge reference pressure sensors access […]
Measuring liquid level in a sealed tank with a hydrostatic pressure sensor
In order to measure the level of a liquid using a pressure sensor you must be able to subtract the pressure of the gas at the top of the tank.
Determining the hydrostatic pressure range for a tank level sensor
There are many ways to measure the height of a fluid and one of the most popular is to use a pressure sensor.
Using a screw-in or waterproof pressure transmitter to measure liquid level
The first step in selecting a pressure transmitter for liquid level measurement is to determine whether to submerge or mount the sensor externally.
Using absolute pressure sensors to measure hydrostatic level
Venting a gauge reference hydrostatic pressure sensor to the outside air is not always possible and an absolute reference sensor has to be used instead.
How to reduce submersible pressure sensor failures caused by moisture ingress
One of the main causes of failure in submersible applications of pressure transducers and transmitters is moisture ingress.