Differential Pressure Sensor

A differential pressure sensor is a sensor used to measure the pressure difference between two points. It typically has two ports, called the high port and the low port. By comparing the pressures at the two ends, it outputs a corresponding differential pressure signal. Unlike common pressure sensors, which only measure absolute or relative pressure at a single point, differential pressure sensors emphasize the precise monitoring of the pressure difference between two points.

Working Principle

The core of a differential pressure sensor typically utilizes a MEMS piezoresistive core, a capacitive measuring element, or a micromechanical structure:

1. When the pressures at the two ends differ, the sensitive diaphragm deforms;
2. This deformation is converted into an electrical signal using resistors, capacitors, or strain gauges;
3. Internal circuitry amplifies, temperature compensates, and digitally processes the signal;
4. The final output is a standard signal (such as a 4-20mA current signal, a 0-10V voltage signal, or an RS485 communication signal).

When the pressures at the two ends are equal, the output is zero differential pressure; when the pressure at the positive port is greater than the pressure at the negative port, the output is a positive differential pressure, and vice versa.

Common Applications

• Heating, Ventilation, and Air Conditioning (HVAC) Systems: Detect airflow pressure differentials in air ducts; monitor the pressure differential across air filters to determine filter blockage.
• Cleanrooms and Laboratories: Monitor indoor and outdoor pressure differentials to maintain positive or negative pressure environments.
• Industrial Process Control: Combined with orifice plates, venturi tubes, or nozzles, they measure gas or liquid flow.
• Liquid Level Measurement: Indirectly measures the liquid level by measuring the pressure differential between upper and lower liquid inlets.
• Environmental Monitoring and Building Automation: Detect pressure differentials in exhaust ducts to ensure ventilation efficiency and safety; aerodynamic experiments and wind tunnel testing.

A differential pressure sensor is a sensor specifically designed to measure the pressure difference between two points. Characterized by high sensitivity and stability, it is widely used in HVAC, cleanrooms, industrial process control, and environmental monitoring. With the advancement of MEMS technology, modern differential pressure sensors not only offer higher accuracy but also provide a variety of standard output signals, facilitating integration into automated and intelligent control systems.