Process instrumentation monitoring refers to real-time monitoring of physical and chemical parameters of liquids and gases in industrial production through process analysis instruments, providing data support for production optimization, safety assurance, and quality control. Its monitoring parameters cover physical indicators (temperature, pressure, flow rate, flow velocity) and chemical indicators (pH value, redox potential, conductivity, etc.), and are widely used in power plants, water plants, biopharmaceuticals, chemical engineering and other fields.
From the perspective of instrument types, process instruments are divided into primary instruments and secondary instruments: primary instruments do not require secondary data processing, such as thermometers (which display temperature through thermal sensitive elements/metal thermal expansion driven pointers) and pressure gauges (which monitor pipeline pressure and are typically used for secondary water supply and pressurization in smart pump rooms). The two are basic instruments with large usage and mature technology in industrial scenarios; Secondary instruments need to process raw signals, such as pH sensors outputting millivolt level signals, which need to be amplified by the instrument to display the pH value. Conductivity and acid-base concentration monitoring instruments also belong to this category, accounting for more than 90% of analytical instruments.
In specific applications, temperature/pressure monitoring ensures equipment safety (such as pipeline pressure of 10 kilograms, overpressure can easily cause accidents); Flow meters can simultaneously monitor flow rate (such as 15 meters per second), instantaneous flow rate, and cumulative flow rate, providing data for water circulation and medium transportation; PH monitoring is particularly crucial - for power plant desulfurization, the pH value of the desulfurization solution needs to be controlled to ensure the desulfurization effect. For biopharmaceuticals, the pH of the culture medium needs to be adjusted according to the requirements of the bacterial strains (neutral bacterial strains should be controlled at 7.0-7.5, and acidic preferred bacterial strains should be controlled at 6.0 or below, otherwise the bacterial strains may die).
Nowadays, process instruments are mostly integrated into automation control systems, and parameters are transmitted to the central control room through data acquisition systems. The central control screen can display multi node parameters in real time (such as temperature and pressure in the east and west areas of a factory spanning 10 kilometers), which facilitates quick analysis and decision-making, and reduces the cost of manual inspection. For special working conditions, customized solutions are also provided: explosion-proof instruments are suitable for hazardous areas, retractable sheath sensors achieve continuous flow maintenance of pipelines, and various material sensors are used to deal with high viscosity and strong corrosive media (such as 85% sulfuric acid, although unable to measure pH, can monitor its temperature, pressure and other parameters).