Pharmaceutical Water for Injection (WFI) equipment is a critical device used in the drug manufacturing process to produce high-purity, sterile water for injection. It mainly includes the following categories:

1. Pretreatment Equipment:
- Raw Water Tank: Stores raw water before initial treatment, typically made of food-grade stainless steel to prevent contamination. Capacity is determined based on production needs.
- Raw Water Pump: Provides the driving force for raw water transportation, moving water from the raw water tank to subsequent treatment equipment. It must ensure stable flow and pressure.
- Multi-Media Filter: Filled with filtration media such as quartz sand and anthracite coal to remove suspended solids, sediment, colloids, and other larger particulate impurities from raw water, achieving preliminary purification.
- Activated Carbon Filter: Utilizes the adsorption properties of activated carbon to remove organic matter, residual chlorine, odors, and some heavy metals from raw water, improving its chemical stability and sensory qualities.
- Softener (Optional): When raw water has high hardness, it uses ion exchange resin to remove calcium, magnesium, and other hardness ions, preventing scale formation in subsequent processes.
2. Reverse Osmosis Equipment (Optional but Commonly Used):
- High-Pressure Pump: Provides sufficient pressure for the reverse osmosis process, forcing water through the reverse osmosis membrane. Pressure typically ranges from 1-10 MPa.
- Reverse Osmosis Membrane Module: The core component, utilizing the principle of semi-permeable membranes to remove the vast majority of salts, organic matter, microorganisms, and other impurities from water. Desalination rates can reach 98%-99% or higher.
3. Distillation Equipment:
- Multi-Effect Distillation Unit: A key device for producing water for injection, commonly using triple-effect, quadruple-effect, or more evaporators. The first-effect evaporator uses external steam to heat the feed water and generate steam, which then serves as the heat source for the second-effect evaporator, and so on. Through multiple evaporation-condensation cycles, impurities, microorganisms, and endotoxins are removed, resulting in high-purity water for injection.
- Condenser: Used to condense the steam produced by the final-effect evaporator into liquid water. It may have shell-and-tube, plate, or other structural designs, using a cooling medium (such as cooling water) to remove heat from the steam and liquefy it.
4. Storage and Distribution Equipment:
- WFI Storage Tank: Made of 316L stainless steel with an electropolished and passivated inner surface to minimize metal ion leaching. The tank is well-sealed and equipped with insulation or heating devices to maintain appropriate water temperature and prevent microbial growth. It also includes a 0.2μm hydrophobic vent filter to balance internal and external pressure and prevent external air contaminants from entering.
- Transfer Pump: Typically made of 316L stainless steel, it transports WFI from the storage tank to various points of use, such as formulation tanks and bottle washers in drug production workshops. It must ensure stable flow, appropriate pressure, and be leak-free and contamination-free.
- Piping System: Primarily constructed from 316L stainless steel with electropolished inner surfaces. Welding processes are stringent, and sanitary fittings are used for connections. Diaphragm valves are commonly employed for their good sealing and ease of cleaning and sterilization, preventing microbial growth and contamination.
5. Auxiliary Equipment:
- Water Quality Monitoring Instruments: Include conductivity meters, Total Organic Carbon (TOC) analyzers, bacterial endotoxin testing instruments, pH meters, etc., to monitor water quality in real time and ensure compliance with relevant standards.
- Disinfection Devices: Such as ultraviolet sterilizers and ozone generators, used for periodic disinfection of pretreatment equipment, storage tanks, and piping systems to maintain a sterile state.