What Does a Differential Pressure Sensor Do?

May 1, 2021

A differential pressure sensor measures the difference in pressure at two points and provides a comparative measurement between the two. These pressure sensors are manufactured by Mid-West Instrument, have numerous applications, and are used in a variety of industries in Michigan.

Differential Pressure Measurement Principle

The differential pressure measurement principle states that differential pressure (also shown as DP or ∆p), is the difference between two applied pressures. For example, if the pressure at point A equals 100psi and the pressure at point B equals 60psi, then the differential pressure is 40psi (100psi – 60psi).

How Does a Differential Pressure Sensor Work?

Typically, the two pressures to be measured are applied to opposite sides of a single diaphragm. The deflection of the diaphragm, either positive or negative concerning the resting state, determines the pressure difference. Some industrial differential sensors use two separate absolute sensors with internal electronics to calculate and provide the pressure difference. Another way to achieve a differential pressure measurement is by using two absolute pressure sensors and then calculating the difference on an industrial control system. This is useful in situations where two different types of sensors are required because of either the medium being measured (i.e. a liquid and a gas) or the environment of the measurement.

Where is a Differential Pressure Sensor Located?

Differential pressure sensors are found in several locations, including:

Flow sensing: used in conjunction with the venturi effect to measure flow. Differential pressure is measured between two segments of a venturi tube that have a different aperture. The pressure difference between the two segments is directly proportional to the flow rate through the venturi tube.

Level/depth sensing: used to measure the depth of a submerged body (such as a diver or submarine) or the level of contents in a tank (e.g. a water tower).

Leak testing: a pressure sensor that senses a drop of pressure due to a system leak. This is done by comparison to a known leak using differential pressure, or by using the pressure sensor to measure pressure change over time.

Differential Pressure Sensor Installation Methods

  • Direct pipeline installation: this installation method is simple and uses the least number of materials.
  • Flange installation: mainly found in liquid level measurement. Uses the static pressure of the liquid to measure the liquid level.
  • Bracket installation (tube-mounted flat bracket): this type of installation is popular due to the convenience it offers for installation and maintenance.

How to Identify a Faulty Sensor

The most common issue with a differential pressure sensor is damage to the diaphragm. This causes the sensor to be deformed or lose the ability to flex and respond to changes in pressure. Another issue that can occur is damage to the port area of the sensor. This could be due to debris or contamination lodging in the port or the tube and restricting the correct flow of fluid into the sensor.

Types of Pressure Sensors

The most common types of differential pressure sensors are:

  • Resistive
  • Capacitive
  • Piezoelectric
  • Optical
  • MEMS

Get in Touch with Our Professional Differential Pressure Sensor Manufacturers in Michigan

If you’d like to incorporate differential pressure sensors into your company’s infrastructure, get in touch with Mid-West Instrument today. We’ll not only help you select the right technology and design, but we’ll also customize the sensor to your exact specifications.