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Differential Pressure | What, How, Why？

2025-07-23

What is Differential Pressure?

Differential pressure refers to the pressure variance between two points. For instance, if pressure at point A is P1 and at point B is P2, the differential pressure from A to B is △P = P1 - P2.

When fluid flows through a pipe, energy loss occurs due to friction and internal collisions, known as pressure drop. This pressure drop creates varying pressures at different points in the pipe, resulting in differential pressure.

Distinction from Pressure Drop

Pressure drop specifically describes the pressure reduction along a pipeline or flow path, caused by flow resistance and friction. It is process-oriented, influenced by fluid properties (density, viscosity) and pipe characteristics, and only occurs when fluid is flowing.

Differential pressure is a numerical difference between pressures at any two points in a fluid system, not limited to pipes. It exists even in static fluids (e.g., due to uneven stress) but not pressure drop.

Causes of Differential Pressure

Manufacturing deviations in components (valves, pumps) lead to varying resistance during operation.

Process adjustments (e.g., fluid speed, temperature changes) alter system conditions.

Pipe blockages, leaks, or wear affect flow dynamics.

Changes in fluid properties (density, viscosity) during production.

Importance of Differential Pressure

Monitors system health: Sudden pressure drops may indicate leaks; spikes suggest blockages (e.g., clogged filters).

Enables flow calculations in industrial pipelines and supports aviation (wing stability) and medical applications (hemodialysis, blood pressure monitoring).

Measuring Differential Pressure

Differential pressure sensors are specialized for this task. Common types include:

Rotor-type: Uses rotational inertia to measure pressure differences, suitable for airflow and oil pressure.

Micro differential pressure sensors: Relies on dual pressure sensors for high accuracy, used in flow meters and braking systems.

Capacitive sensors: Detects capacitance changes from elastic element deformation, sensitive to small pressures.

Resistive sensors: Measures resistance changes in deformed metals, ideal for aerospace.

Torsion spring sensors: Uses material deformation to calculate pressure differences, suited for water treatment and petrochemicals.

Some great products that solve problems

E&H Electronic differential pressure Deltabar FMD72

The electronic differential pressure system Deltabar FMD72 is designed to measure the pressure, level, volume or mass of liquids in pressurized tanks, distillation columns or evaporators. The high - pressure sensor (HP) is responsible for measuring hydrostatic pressure, while the low - pressure sensor (LP) measures head pressure. The level is calculated in the transmitter based on these two digital values. This electronic differential pressure system overcomes the problems associated with traditional differential pressure measurement methods.

Accuracy

0.075% of individual sensor,

"PLATINUM" 0.05% of individual sensor

Process temperature

–40...+125°C

(–40 ... +257°F)

Pressure measuring range

400 mbar...10 bar

(6 psi...150 psi)

Process pressure / max. overpressure limit

160 bar (2400 psi)

Main wetted parts

316L, Alloy C

Material process membrane

316L, AlloyC,

Measuring cell

400 mbar...10 bar

(6 psi...150psi)

Differential Pressure Level Measurement

Differential Pressure (DP) Level Measurement uses pressure readings and specific gravity to output level. DP Level is a common measurement technique that is used in a wide variety of applications. Solutions include standard transmitter connections and integrated transmitters with direct or remote mount seals that can be configured in tuned, balanced, and electronic systems. Additional Wireless options are also available.
Emerson is capable of addressing process and ambient temperatures up to 770°F (410°C) and temperatures as low as -75°C (-103°F) with the use of the:
Thermal Range Expander
Graphic References: ​
Intermediate diaphragm​
Ambient temperature fill fluid​
High temperature fill fluid (viscous)​

Ifm  Mechatronic flow meters in high-pressure 
Specifically adjusted to oil for optimum measurement results
Measured value transmission without conversion losses and easy setting via IO-Link
No inlet and output pipe lengths required
Integrated temperature measurement and compensation
High measurement dynamics reduces type version

Flow transmitter with integrated backflow preventionSBU924

Application



Application
machine tools; Internal cooling of drill

Media
Liquids; water; glycol solutions; coolants

Medium temperature
0...60

Pressure rating
200 bar

Electrical data



Operating voltage tolerance[%]
-15...10

Operating voltage[V]
24 DC; (to SELV/PELV)

Current consumption[mA]
10

Protection class
III

Reverse polarity protection
yes


 https://www.achieversinstruments.com/    and more high pressure flow meter


Achievers Automation Limited is a well-established player in the field of industrial automation, boasting a rich and extensive experience of more than 12 years. 
Over these years, the company has dedicated itself to dealing with a comprehensive and complete range of industrial automation components and instruments. With an unwavering commitment to excellence, the team at Achievers always goes the extra mile, striving their absolute best to provide top-notch quality goods and highly efficient, timely services to our esteemed and valued customers. 
These customers hail from over 45 countries across the globe, spanning different continents and diverse industrial landscapes.

Blog Details

Home Blog

Differential Pressure | What, How, Why？

What is Differential Pressure?

Differential pressure refers to the pressure variance between two points. For instance, if pressure at point A is P1 and at point B is P2, the differential pressure from A to B is △P = P1 - P2.

When fluid flows through a pipe, energy loss occurs due to friction and internal collisions, known as pressure drop. This pressure drop creates varying pressures at different points in the pipe, resulting in differential pressure.

Distinction from Pressure Drop

Pressure drop specifically describes the pressure reduction along a pipeline or flow path, caused by flow resistance and friction. It is process-oriented, influenced by fluid properties (density, viscosity) and pipe characteristics, and only occurs when fluid is flowing.

Differential pressure is a numerical difference between pressures at any two points in a fluid system, not limited to pipes. It exists even in static fluids (e.g., due to uneven stress) but not pressure drop.

Causes of Differential Pressure

Manufacturing deviations in components (valves, pumps) lead to varying resistance during operation.

Process adjustments (e.g., fluid speed, temperature changes) alter system conditions.

Pipe blockages, leaks, or wear affect flow dynamics.

Changes in fluid properties (density, viscosity) during production.

Importance of Differential Pressure

Monitors system health: Sudden pressure drops may indicate leaks; spikes suggest blockages (e.g., clogged filters).

Enables flow calculations in industrial pipelines and supports aviation (wing stability) and medical applications (hemodialysis, blood pressure monitoring).

Measuring Differential Pressure

Differential pressure sensors are specialized for this task. Common types include:

Rotor-type: Uses rotational inertia to measure pressure differences, suitable for airflow and oil pressure.

Micro differential pressure sensors: Relies on dual pressure sensors for high accuracy, used in flow meters and braking systems.

Capacitive sensors: Detects capacitance changes from elastic element deformation, sensitive to small pressures.

Resistive sensors: Measures resistance changes in deformed metals, ideal for aerospace.

Torsion spring sensors: Uses material deformation to calculate pressure differences, suited for water treatment and petrochemicals.

Some great products that solve problems

E&H Electronic differential pressure Deltabar FMD72

Accuracy

0.075% of individual sensor,

"PLATINUM" 0.05% of individual sensor

Process temperature

–40...+125°C

(–40 ... +257°F)

Pressure measuring range

400 mbar...10 bar

(6 psi...150 psi)

Process pressure / max. overpressure limit

160 bar (2400 psi)

Main wetted parts

316L, Alloy C

Material process membrane

316L, AlloyC,

Measuring cell

400 mbar...10 bar

(6 psi...150psi)

Differential Pressure Level Measurement

Differential Pressure (DP) Level Measurement uses pressure readings and specific gravity to output level. DP Level is a common measurement technique that is used in a wide variety of applications. Solutions include standard transmitter connections and integrated transmitters with direct or remote mount seals that can be configured in tuned, balanced, and electronic systems. Additional Wireless options are also available.
Emerson is capable of addressing process and ambient temperatures up to 770°F (410°C) and temperatures as low as -75°C (-103°F) with the use of the:
Thermal Range Expander
Graphic References: ​
Intermediate diaphragm​
Ambient temperature fill fluid​
High temperature fill fluid (viscous)​

Ifm  Mechatronic flow meters in high-pressure 
Specifically adjusted to oil for optimum measurement results
Measured value transmission without conversion losses and easy setting via IO-Link
No inlet and output pipe lengths required
Integrated temperature measurement and compensation
High measurement dynamics reduces type version

Flow transmitter with integrated backflow preventionSBU924

Application



Application
machine tools; Internal cooling of drill

Media
Liquids; water; glycol solutions; coolants

Medium temperature
0...60

Pressure rating
200 bar

Electrical data



Operating voltage tolerance[%]
-15...10

Operating voltage[V]
24 DC; (to SELV/PELV)

Current consumption[mA]
10

Protection class
III

Reverse polarity protection
yes


 https://www.achieversinstruments.com/    and more high pressure flow meter


Achievers Automation Limited is a well-established player in the field of industrial automation, boasting a rich and extensive experience of more than 12 years. 
Over these years, the company has dedicated itself to dealing with a comprehensive and complete range of industrial automation components and instruments. With an unwavering commitment to excellence, the team at Achievers always goes the extra mile, striving their absolute best to provide top-notch quality goods and highly efficient, timely services to our esteemed and valued customers. 
These customers hail from over 45 countries across the globe, spanning different continents and diverse industrial landscapes.

Application
Application		machine tools; Internal cooling of drill
Media		Liquids; water; glycol solutions; coolants
Medium temperature		0...60
Pressure rating		200 bar
Electrical data
Operating voltage tolerance[%]		-15...10
Operating voltage[V]		24 DC; (to SELV/PELV)
Current consumption[mA]		10
Protection class		III
Reverse polarity protection		yes

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Bently Nevada Proximity Probe

Endress Hauser Instruments

Allen Bradley PLC Controllers

Pepperl Fuchs Safety Barrier

TE Dynamic Products

MTL Instruments

Yokogawa Instruments

DETCON Gas Detection

Phoenix Contact Products

Rosemount PH Sensors

Asco Electric Solenoid Valve

SICK Instruments

IFM Sensor

Festo Cylinder

SIEMENS PLC Products

EMERSON TREX Device Communicator

SMC Instruments

ABB Positioner

Blog Details

Differential Pressure | What, How, Why？

Differential Pressure | What, How, Why？

What is Differential Pressure?

Distinction from Pressure Drop

Causes of Differential Pressure

Importance of Differential Pressure

Measuring Differential Pressure

E&H Electronic differential pressure Deltabar FMD72

Differential Pressure Level Measurement

Ifm Mechatronic flow meters in high-pressure

Flow transmitter with integrated backflow prevention

SBU924

Differential Pressure | What, How, Why？

Differential Pressure | What, How, Why？

What is Differential Pressure?

Distinction from Pressure Drop

Causes of Differential Pressure

Importance of Differential Pressure

Measuring Differential Pressure

E&H Electronic differential pressure Deltabar FMD72

Differential Pressure Level Measurement

Ifm Mechatronic flow meters in high-pressure

Flow transmitter with integrated backflow prevention

SBU924