A guide to differential pressure measurement including explanations, applications and choice of products for measuring pressure with an differential pressure.
Differential pressure is the difference in pressure between two separate points.
A differential pressure can be measured between two points on independent systems or between two different points on the same system.
DPS300 User Switchable Pressure Range, Volts or Current Output Low DP Sensor - The DPS 300 is a low range HVAC differential pressure sensor. The lowest possible pressure range is 0...100 pascals. 2 or 3 switchable pressure ranges, plus volts or current output are included with most standard configurations.
DPS Low Differential Pressure Transmitter - Ultra low differential pressure transmitter for HVAC applications with 4-20mA current loop or amplified voltage output signal in pressure ranges from 0.1 mb up to 1 bar differential. 
DMD331 Compact Differential Liquid Pressure Sensor - Wet wet differential pressure sensor with a high overpressure rating on both positive and negative pressure side for protection against damage.
DPT200 High One Side Overload Differential Pressure Sensor - DP transmitter for measuring pressure difference between two pressure points which can tolerate up a very high overload pressure independently on either the positive or negative side port or both together at the same time.
901 Prescal Pressure Switch Specification and Data Sheet -
Adjustable pressure switch for monitoring overpressure (5 mbar up to 12 bar), vacuum (-5 to -700 mbar) or differential pressure (5 to 50 mbar) of liquid, gas and aggressive media.
Pressure Calibrator for Pressure Transmitter Calibration – ADT672 - The ADT672 series of pressure calibrators are precision digital pressure gauges with electrical measurement for pressure transmitter calibration
- Bidirectional -50 to +50 Pa diff pressure transmitter with user calibration adjustment
- Clean room monitoring system to measure pressure, humidity & temperature in 4 individual rooms
- 100 Pa bi-directional range differential air pressure transmitter
- 20 pascal differential pressure transducer for clean rooms
- 10 mbar range differential pressure calibrator
- 20 Pa DP range 0-10V output air pressure sensor for building management use
Differential Pressure Transmitters - Differential pressure transmitters for measuring the DP of fluids and gases across particle filters and along a length of pipe to monitor flow.- Voltage Output DP Transducers - Differential pressure transducers with amplified 0-5V, 1-5V, 0-10V, and 1-10V outputs for precise liquid and gas DP measurement in demanding industrial and research applications. Enhanced signal clarity and 3-wire configuration.
Digital Interface DP Sensors - Explore our range of differential pressure sensors featuring RS485, RS232, and USB digital interfaces.
Air DP Sensors - Air differential pressure sensors play a vital role in maintaining environmental control and safety within critical applications such as cleanrooms, laminar flow cabinets, and ventilation systems.- Low Differential Pressure Transmitters - Select highly sensitive low DP transmitters designed for critical applications like ventilation control, hospital isolation rooms, and laboratory environments. Features include 4-20mA signals, displays, and alarm contacts.
Low Range DP Sensors - Low range differential pressure sensors for measuring very small pressure differences.
Find out more about our Differential Pressure to determine which product options and capabilities will best meet your application requirements.
Applications
The main use for a differential pressure sensor is to measure the difference in fluid or gas pressure across a restriction in a pipe. The flow can then be determined by converting the differential pressure reading with bernoulli’s equation. Since flow is proportional to the square root of the differential pressure in a closed pipe it is sometimes preferred to use a square root output signal from the differential pressure sensor to simplify the conversion to a flow measurement.
Other applications for measuring differential pressure are as follows:
Hydrostatic level measurement of a tank’s content, where the gas at the top of the tank is not vented. The difference in pressure between the bottom and the top is measured to determine the true hydrostatic pressure.
Leakage monitoring by measuring the difference in pressure between a controlled reference pressure and the component under test pressurised to the same pressure.
Airspeed using a Pitot tube which provides two air channels, one for measuring the total air pressure facing the airflow and the other for the static pressure measured perpendicular to the air-flow. The difference between the two channels provides the air velocity pressure. This method is used on aircraft to measure air speed and in wind tunnels to simulate air velocity for testing the aerodynamics of an object.
Questions & Answers
Differential vs Gauge
When do you need to measure differential pressure instead of gauge pressure?
You would you use a differential when you need to measure pressure between 2 connection points, and when the reference pressure (negative side) is not the same as atmospheric pressure.
Which side of DP transmitter to connect to vacuum
Which side of the impulse line connections for a dp transmitter is the blower vacuum or suction side?
If the output of the dp transmitter is scaled for a positive pressure range, e.g. 0 to +1 bar = 4 to 20 mA, then you can measure 0 to -1 bar suction but connecting the vacuum to the negative side, and leaving the positive side vented to atmosphere.
Related Help Guides
- Measuring the difference in air pressure between rooms
- Measuring liquid level in a sealed tank with a hydrostatic pressure sensor
- Measuring negative pressure using a positive differential pressure range
- Measuring vacuum as a negative gauge pressure using a dp sensor
- Measuring liquid level in a tank using a dp sensor
- Measuring density of a liquid using a dp sensor
Related Product and Application Guides
Related Technical Terms
Related Online Tools
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