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.
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.
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.
Wet / Wet Differential Pressure Sensors - Wet/Wet differential pressure transducers and transmitters which are compatible with liquids on both positive and negative side process connections.
Low Range DP Sensors - Low range differential pressure sensors for measuring very small pressure differences.
DPT100 Modbus RTU RS485 Differential Pressure Sensor
DPS200 HVAC Differential Pressure Transmitter- DPS300 User Switchable Pressure Range, Volts or Current Output Low DP Sensor
LEO Record (Ei) Capo Low Pressure Logger
DPS Low Differential Pressure Transmitter
DPT200 Pressurised Tank Level Differential Pressure Transmitter
901 Prescal Pressure Switch Specification and Data Sheet- DPT200 High One Side Overload Differential Pressure Sensor
DMD331 Compact Differential Liquid Pressure Sensor
41X Low Range Digital Output Pressure Sensor
Pressure Calibrator for Pressure Transmitter Calibration – ADT672
Clean Room Monitor for Air Differential Pressure, Temperature and Humidity – PMDS4
- Biogas ATEX 4-20mA pressure transmitter for low pressure anaerobic digestion monitoring - Enhance process safety in methane production with this intrinsically safe pressure transmitter featuring 316L stainless steel and FKM seals for superior chemical compatibility in low-pressure biogas environments.
Clean room monitoring system to measure pressure, humidity & temperature in 4 individual rooms - A complete clean room measurement system for 4 separate rooms, each with its own room pressure, humidity and air temperature indicator, and a central monitoring unit for clean room corridor or control room.
Monitoring intake filter differential pressure in industrial air compressors - Monitor the pressure drop across industrial air compressor intake filters to trigger maintenance alarms and improve energy efficiency with precise analog signal output.- Bi-directional room pressure sensing in explosive gas and dust atmospheres - Optimize facility safety in chemical and pharmaceutical plants by maintaining accurate pressure gradients between labs and hazardous production areas.
Laboratory environment monitor for precise room pressure, temperature and humidity - Monitor and maintain critical atmospheric conditions with an integrated system featuring bi-directional pressure sensing, ambient temperature measurement, relative humidity tracking, and local relay control.
Air Replacement Plant (ARP) 100 mm H2O differential pressure transmitter - Differential pressure transmitters for instant monitoring of the air flow going through the painting booth interior- Using 25 mbar DP sensor on vacuum below 0.2 bar absolute - I would like to measure a differential pressure of 0 to 25 mbar in a vacuum of < 0.2 bar absolute pressure.
- Low range ATEX approved 100 Pascal range DP transmitter - The DPT200 is a robust ATEX approved differential pressure transmitter which has a very low range of 100Pa.
- Biogas HDPE cover PD blower pressure sensor - The XMD is a low range process pressure transmitter with an all stainless steel 316L wetted parts suitable for measuring the pressure of a biogas inflated HDPE cover to control a positive displacement pump.
- Engine test cell fuel filter 2.5 bar differential pressure sensor with ATEX approval - Sensor to measure differential pressure across fuel filters in an engine test cell on diesel and kerosene.
- 100 Pa bi-directional range differential air pressure transmitter - Bi-directional low range 4 to 20 milliamp differential pressure transmitter covering an air pressure range from -100 to +100 pascals, for cleanrooms, isolation rooms, and filter monitoring.
- 10Pa diff range 0-20mA output air pressure sensor for automotive component testing - A very low range pressure sensor for automotive component testing use to measure pressure of air over a range of 0 to 10 Pa diff from two barbed tube hose connections, and sending the corresponding 0-20mA signal through the DIN plug electrical connection.
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
- How do you measure flow rate with a dp cell
- 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
- What can a DP sensor be used to measure beyond differential pressure?
- Measuring flow rate of a liquid or gas using a dp sensor
- Measuring gauge pressure using a dp sensor
- Measuring absolute pressure using a dp sensor
- Measuring barometric pressure using a dp sensor
- Measuring vacuum as an absolute range using a dp sensor
- What does the suffix a, abs, d, dp and diff, g, rel and sg mean after the pressure units in a pressure range?
Related Technical Terms
Related Online Tools
Related Product and Application Guides
Related Application Questions and Answers
- Air Replacement Plant (ARP) 100 mm H2O differential pressure transmitter
- Using 25 mbar DP sensor on vacuum below 0.2 bar absolute
- Low range ATEX approved 100 Pascal range DP transmitter
- Biogas HDPE cover PD blower pressure sensor
- Engine test cell fuel filter 2.5 bar differential pressure sensor with ATEX approval
- USB pressure sensors for detecting water leaks & restrictions
- Solvent compatible +/-100mWG dp transmitter with PTFE seals
- Vacuum pump inlet to outlet differential pressure sensor with 1500 Torr range
- Clean room temp, RH and pressure monitoring
- Low delta P sensor with 200mmH2O range and response time < 5ms
- Negative room pressure monitor and logger for multiple zones
Contact us about this Differential Pressure page to request more information, or to discuss your application requirements.