Intelligent Sensors in Pure Water Production

The term ultrapure water (UPW) is commonly used in many industries. While each industry uses what it calls ultrapure water, the quality standards vary. This means that UPW used by a power plant is different than that used in a semiconductor fab or by the pharmaceutical industry. So a number of organizations developed and published standards associated with the production of UPW, i.e. ASTM (D5127) for electronics and semiconductor industries, EPRI for power plants, and USP, EP, and JP for the pharmaceutical industry. Although the standards vary, some applications might be similar. For example, UPW is used as a cleaning or rinsing agent in semiconductor fabs and in the pharmaceutical industry. The latter uses UPW additionally for other applications, such as an ingredient in their final products or to generate steam for sterilization.

Therefore,  it must not only be extremely low in particles, silica, and non-volatile residue but also free of microbials, viruses, and endotoxins. To meet the specifications outlined in the pharmacopoeias, the water is treated in multiple steps: a pretreatment stage to produce purified water, a primary stage to further purify it, and a polishing stage. The polishing stage is a set of treatment steps and is usually a recirculation and distribution system, continuously treating and recirculating the purified water in order to maintain a stable, high-purity quality of supplied water. Traditionally, the resistivity, and thus the conductivity, of water serves as an indication of the purity of UPW.

Conductivity measurement is a common indicator of ionic contamination, caused by a breakthrough of a depleted ion exchanger. UPW is also easily contaminated by trace amounts of atmospheric carbon dioxide that pass through tiny leaks. Carbon dioxide forms conductive carbonate or hydrogen carbonate ions, as well as hydrogen ions in water. For these reasons, real-time monitoring of contamination in the main ultrapure water system is required by inserting conductivity sensors. 

CIFA Group is well known for engineering, designing, installing, and maintaining purified water facilities and water for injection (WFI) loops. Their skids are widely used in the pharmaceutical, biotechnology, and food industries. CIFA not only builds the skids but also does the automation of all devices via Profinet. For this purpose, CIFA was looking for sensors that allow an easy integration by providing a robust digital signal directly to the process control system. The configuration is done via RS-485 interface, providing different addresses to each sensor, and allowing the download of a configuration file for each sensor. This allows copying sensor configurations and the storage of all sensor data.

Another benefit of the Arc technology is that bulky external transmitters are no longer needed which allows either for smaller electrical cabinets or for their more efficient utilization. Furthermore, Arc sensors can be upgraded with wireless adapters that allow Bluetooth communication with smartphones and tablets via the ArcAir app. Due to the highly reliable measurements provided by the Arc sensors and the certificates delivered with the sensors have led CIFA to choose Hamilton as their preferred supplier for pH, ORP, and conductivity measurements.

Author

Cristian Hernández

Service Manager

Company

CONSULTORÍA E INSTALACIONES

FARMACÉUTICAS Y ALIMENTARIAS S.L.

Spain

www.cifa.es/en

End-Customer

Laboratorios Inibsa S.A.

Spain