What Is a Wireless Pressure Sensor?
A wireless pressure sensor measures pressures, such as gauge pressure, in factories and plants without needing wired connections for power or communication.
In many industrial settings, it is essential to measure and manage the pressure of gases and liquids, including gauge pressure, sealed gauge pressure, and differential pressure. Traditional wired pressure sensors require long power cables and can have installation limitations. Wireless pressure sensors eliminate these restrictions, allowing for installation in desired locations. The power sources are mainly divided into battery-powered and self-powered types. Additionally, some products are used in educational settings for scientific experiments.
Uses of Wireless Pressure Sensors
Wireless pressure sensors are used in various industrial applications, including power plants, chemical plants, oil refineries, and food processing facilities.
Many industrial processes involve the use of pressurized gases or pressurized containers. Monitoring pressure is crucial as pressurized leaks or container expansions can disrupt the safe operation of manufacturing processes. Primary uses include:
- Online and remote gauge monitoring
- Valve leakage monitoring
- Monitoring pipeline and filter blockages
- Measuring gas and liquid flow rates
- Tank level measurement
- Monitoring gas and liquid filters
- Process control in factories
Wireless pressure sensors are also used in educational settings for various physics and chemistry experiments, such as Boyle’s law and measuring pressure inside balloons.
Principle of Wireless Pressure Sensors
Measurement Mechanism
Wireless pressure sensors measure the pressure of gases or liquids via a diaphragm and convert it into an electrical signal using a pressure-sensitive element.
A semiconductor piezoresistive diffusion pressure sensor forms a semiconductor strain gauge on the diaphragm’s surface. The diaphragm deforms under pressure, causing a change in electrical resistance due to the piezoresistive effect, which is then converted into an electrical signal. The piezoresistive effect is the change in electrical resistivity caused by applied stress, different from the piezoelectric effect, which is the polarization phenomenon caused by stress.
A capacitive pressure sensor forms a capacitor with a fixed glass electrode and a movable silicon electrode. The change in capacitance due to the deformation of the movable electrode under pressure is converted into an electrical signal.
Power Source
Wireless pressure sensors come in battery-powered and self-powered or energy-harvesting types. Battery-powered types use various batteries like button cells, AA, AAA, and lithium batteries.
Self-powered types do not require batteries and operate by collecting waste energy from surrounding heat, vibration, etc. Energy sources include temperature differences, vibrations, sunlight, and magnetic fields. This eliminates the need for battery maintenance and reduces operational costs.
Data Transmission
Wireless pressure sensors use various wireless communication methods for data transmission to data loggers, such as Wi-Fi, Zigbee, Lora, LoRaWAN, and Bluetooth. The suitable data communication method is chosen depending on the product and application. For instance, LoRaWAN offers excellent reception sensitivity and resistance to radio interference, allowing for communication distances of over 10 km in ideal environments, making it suitable for wide-area operations. Additionally, some products enable status checking via smartphones.
Types of Wireless Pressure Sensors
Overview
Wireless pressure sensors come in various types, each with different specifications and features. The pressure range, durability, and suitable applications vary by product, so it is necessary to select the appropriate one based on the intended use.
Data Management
Some products allow data to be saved in CSV format for statistical maintenance and management of equipment. Products with mechanical pressure gauges equipped with pressure sensors and communication modules enable pressure readings on-site even when communication is unavailable. Sampling intervals vary by product, from 0.1-second units to minute units, and some offer real-time data display.
Waterproof and Dustproof
Products with an IP65 waterproof rating can be used in wet environments or outdoors. While many products are unsuitable for corrosive gases and fluids, some can measure contaminated water, steam, and slightly corrosive fluids.
Products with explosion-proof certification can be installed in hazardous areas handling flammable gases, such as petrochemical plants, paint factories, and chemical plants.