Abstract : Purified water is a widely used process water in pharmaceutical manufacturing, and it is crucial for the safety of drug production and users. This article briefly introduces the preparation process of pharmaceutical-grade purified water and the application of Delta's electromechanical products in purified water equipment. By using Delta's PLCs, HMIs, frequency converters, and other products, the purified water production equipment becomes more operable and the processing is more automated.
Keywords : purified water, human-machine interface, programmable logic controller, frequency converter
1. Introduction
Water is a precious resource essential for human survival and a crucial raw material for pharmaceutical production. The quality of water used in the pharmaceutical industry, especially raw water for pharmaceutical manufacturing, directly impacts drug production and safety. Over the years, purified water preparation processes have evolved from simple single-unit equipment to complete systems. Correspondingly, water purification technologies have also seen significant development, progressing from simple manual methods to centralized automated control. The following is a brief introduction to purified water preparation and the application of Delta Electronics products in water purification equipment.
2. Introduction to Process and Equipment
Water under natural conditions constantly comes into contact with the air, the earth's surface, the subsurface, and dissolves rocks and soil, resulting in various impurities. These impurities can be mainly divided into three categories: (1) suspended matter such as silt, plant and animal remains, and microorganisms; (2) colloids, primarily aggregates of various molecules and ions; and (3) dissolved substances existing as individual free molecules or ions.
Pharmaceutical water is process water without any additives. The system control of pharmaceutical water must control the content of these impurities, while also effectively treating and controlling microbial and bacterial endotoxin contamination. Commonly used processes include ion exchange resin exchange, distillation and condensation, electrodialysis, and reverse osmosis. The preparation process is roughly divided into five parts: pretreatment, primary desalination unit, deep desalination unit, post-treatment unit, and pure water delivery and distribution system. Purified water equipment includes mechanical and electrical components: the mechanical components mainly consist of water pumps, pressure tanks, water tanks, solenoid valves, filters, and pipelines; the electrical components mainly consist of programmable logic controllers (PLCs), touch screens, frequency converters, pressure gauges, relays, etc. Figure 1 shows a field demonstration case of purified water preparation.
Figure 1 Purified water production equipment
3. Control Structure
Based on the project process control requirements proposed by the client, the architecture of this control system is shown in Figure 2.
Control system hardware configuration: Delta DOP-B10S615 touchscreen, Delta DVP32ES200R programmable logic controller (PLC), DVP04AD-E2 PLC expansion analog module, and Delta VFD185F43A frequency converter. The system has two operating modes: automatic and manual. Automatic control uses a combination of multi-point, multi-channel water level sensors and a dynamic pressure controller to monitor the operation of each component, and time relays for timing calculations to achieve automatic system operation. Manual operation is mainly used for system installation, commissioning, and maintenance.
Figure 2 Control System Architecture
4. Program Description
The main function of the touchscreen is to display and control data during the water production process, as well as the operating status of the water pump and solenoid valves. PLC inputs include the opening and closing status of each valve, and the liquid level and pressure status of each tank. The liquid level input is an analog signal. Outputs include pump start/stop, solenoid valve opening/closing, alarms, etc. Figure 3 shows a portion of the touchscreen's control interface (initial design).
Figure 3-a Touchscreen control interface (initial design)
Figure 3-b Touchscreen control interface (initial design)
A PLC program mainly consists of the following components: initialization, analog signal acquisition, data processing, logic control (manual and automatic), and alarm. Figure 4 shows a partial PLC program design.
Figure 4 PLC Programming
5. Conclusion
With the development of science and technology, people have increasingly higher requirements for water quality (including medical and drinking water). To obtain qualified purified water, the automation requirements for water treatment equipment are also increasing. The application of Delta's electromechanical products has greatly improved the operability of purified water preparation systems, while also significantly enhancing their automation level and control precision. This has gained recognition from many purified water equipment manufacturers, demonstrating a promising market prospect and facilitating widespread adoption.
About the author:
Liu Hongfeng, born in December 1980, graduated from Hebei University of Science and Technology with a major in Electrical Engineering and Automation. He currently works as an Application Engineer at Delta Electronics Co., Ltd.'s Beijing branch. His main job is to be familiar with various products and their applications, and to provide customers with technical support and overall solutions.
