What are Pressure Sensors/Pressure Transducers and How Do They Work?
Pressure sensors, or pressure transducers, are instruments that convert the measured mechanical pressure of a gas or liquid into an electrical output signal for control and monitoring purposes.
The electronic components of a pressure sensor generate an electrical signal when force is applied to the pressure-sensitive elements. The signals are generally analogue or digital; although other types such as visual and optical are also used.
For force collector type technologies, a strain gauge such as a diaphragm is used to measure the strain (or deflection) that results from an applied force over an area — pressure. The electrical resistance measured from the gauge then changes in proportion to the pressure-induced strain.
With capacitive technology, a capacitor plate is used as the diaphragm, which displaces under pressure-induced strain, changing the output capacitance.
4-20mA, 0-5 V and 0-10 VDC are common analogue output options for most types of pressure sensing technologies.
Strain gauge and capacitive technologies are just some of the many types used in pressure sensors. Learn more about how different pressure-sensing technologies work here.
How are Pressure Sensors Used?
Pressure sensors are used extensively across industry to make processes smarter, safer and more efficient to operate. Suitable for different industries, media and applications, some common uses of pressure sensors include:
- Measuring gas and liquid pressures
- Monitoring safe levels in liquid tanks
- Monitoring process flows
- Managing control loops
Types of Pressure Measurements
The type of pressure sensor technology you choose can differ depending on the type of pressure measurement you need to monitor. These measurements are:
- Absolute pressure: pressure measured relative to full vacuum. Readings from sensors that measure absolute pressure do not change with shifts in atmospheric pressure.
- Gauge pressure: pressure measured relative to atmospheric pressure. Readings from sensors that measure gauge pressure will be affected by changes in atmospheric pressure.
- Differential pressure: the difference in pressure between two points in a system.
Pressure sensors or pressure transducers can make use of different measurements to quickly and accurately infer other process variables such as level, flowrate and velocity.
Types of Pressure Sensors
The type of pressure sensor used depends heavily on the application as well as the type of pressure being measured. Some of the common technologies include:
- Piezoresistive - Measures the change in electrical resistance resulting from the mechanical displacement of the strain gauge.
- Capacitive - Measures the change in electrical capacitance resulting from the mechanical displacement of the capacitor plate.
- Piezoelectric - Uses quartz, ceramics or other special materials that generate a charge on its surface when subjected to mechanical stress. The magnitude of the charge is proportional to the pressure applied.
As one of the leading suppliers of high-performance pressure sensors in the UK, we carry a wide selection of pressure transducers with a range of sensing technologies including capacitance, CVD, sputtered thin film and MMS types.
Selection Criteria for Pressure Sensors/Pressure Transducers
Having the correct pressure sensor specification is essential to enable accurate and reliable monitoring and control of your processes. Careful consideration of your system requirements can help ensure you select the right, fit-for-purpose sensor. Aspects to consider can include:
- Sensing technologies
- Pressure range, type and units of measurement
- Accuracy requirements
- Operating conditions (e.g. temperature, pressure)
- Process media
- Materials of construction
- Electrical and process connection options
- Signal output requirements (analogue or digital)
- Integrated/detached/without display
- IP protection requirements
- Required certifications (e.g. SIL2 rated or 3.1 material certificates)
- Hazardous area considerations (e.g. ATEX rating)
Our knowledgeable technical support team are experts in working across different industries and experienced in specifying pressure sensors to suit different system, operating and measurement requirements. Even for the most demanding and performance-critical systems, our pressure sensor UK specialists can work flexibly with you to specify the most optimal solution to suit your technical and delivery needs.
Accurate and meaningful pressure measurements are critical to safe, reliable and efficient operations, so it is important to specify and install the right pressure sensor for your process. As a specialist pressure sensors UK supplier, we have a wide variety of high-performance pressure sensors in stock and available for different fluids, environments and measurement applications. Speak with our experts or explore our extensive portfolio to discover high-accuracy pressure-sensing solutions that you can trust with any measurement challenge.