2.1 Wireless Pressure Transmitters

Wireless pressure transmitters are the workhorses of oil and gas monitoring. They measure gauge or absolute pressure of liquids, gases, and steam, transmitting data wirelessly to a central system.

Key Specifications to Look For:

Measurement Principles:

• Diffused Silicon Piezoresistive: Cost-effective, good stability for general applications

• Single Crystal Silicon Resonant: Higher accuracy and long-term stability, suitable for demanding applications

• Ceramic Capacitive: Excellent corrosion resistance for aggressive media

2.2 Wireless Temperature Transmitters

Temperature is equally critical in oil and gas operations—from wellhead fluid temperatures to pipeline transport conditions to refinery process control.

Wireless temperature transmitters typically use Pt100 platinum resistance temperature detectors (RTDs) as the sensing element, offering:

• Measurement Range: -50°C to +250°C (extended ranges available)

• Accuracy: Class A or better

• Sensor Type: Pt100 RTD, thermocouple options available for extreme temperatures

Many modern wireless temperature transmitters can also measure both temperature and pressure simultaneously, providing comprehensive wellhead or pipeline monitoring in a single device.

2.3 Explosion-Proof and Intrinsic Safety Design

Oil and gas environments are classified as hazardous areas due to the presence of flammable gases and vapors. Wireless transmitters deployed in these environments must carry appropriate certifications:

• Ex d IIC T6 Gb (Flameproof/Explosion-proof): The device housing contains any internal explosion, preventing ignition of the surrounding atmosphere.

• Ex ia IIC T4 Ga (Intrinsic Safety): The device is designed so that any spark or thermal effect is too low to cause ignition, even under fault conditions.

The T6 temperature class is the highest rating, indicating the device’s maximum surface temperature does not exceed 85°C—critical in environments with low-ignition-temperature gases.