1.1 Pressure Instruments: Local pressure gauges, remote differential pressure transmitters, or pressure switches that transmit digital signals.
1.2 Temperature Instruments: Contact and non-contact thermometers.
1.3 Flow Meters: Volumetric flow meters output signals reflecting volumetric flow rate, including electromagnetic flow meters, vortex flow meters, and ultrasonic flow meters. Mass flow meters can be categorized into two types: direct-reading, which directly outputs mass flow rate; and indirect or derived-type. Direct-reading mass flow meters include various types such as calorimetric, angular momentum, gyroscopic, and dual-rotor types. Indirect mass flow meters have three main types: a combination of a velocity flow meter and a density meter, a combination of a throttling (or orifice) flow meter and a volumetric flow meter, and a combination of a throttling (or orifice) flow meter and a density meter.
1.4 Level Instruments: Depending on the measured medium, they can be classified as liquid level meters (gas-liquid), material level meters (gas-solid), and interface level meters (liquid-liquid, solid-liquid). Commonly used level meters in water treatment processes include magnetic float level meters, ultrasonic level meters, and pressure-type level meters.
1.5 Analytical Instruments: Analytical instruments are mainly divided into gas analyzers and liquid analyzers. Gas analyzers include gas chromatographs, infrared analyzers, and thermal conductivity analyzers; liquid analyzers include pH meters, conductivity analyzers, water quality analyzers, and viscometers.
