Medical water for injection equipment is used to produce high-purity water that meets the requirements for medical injections.

1. Main Equipment Components
- Pretreatment Section
- Raw Water Tank: Stores raw water, with its capacity determined by production scale. Typically made of stainless steel to prevent the dissolution of impurities and microbial growth.
- Raw Water Pump: Provides the driving force for raw water, ensuring it flows steadily into subsequent treatment equipment. It must maintain appropriate flow and pressure for smooth system operation.
- Multi-Media Filter: Usually contains filtration media such as quartz sand and activated carbon. Quartz sand filters out larger suspended particles, sediment, and silt from the water; activated carbon adsorbs organic matter, residual chlorine, and some heavy metals, removing odors.
- Softener (if needed): Used when the raw water has high hardness. It removes calcium, magnesium, and other ions through ion exchange resin to prevent scale formation in subsequent equipment, which could affect performance and water quality.
- Reverse Osmosis System (common but not mandatory)
- High-Pressure Pump: Provides sufficient pressure for the reverse osmosis process, enabling water to overcome osmotic pressure and pass through the reverse osmosis membrane. The pressure range is typically between 1 - 10 MPa.
- Reverse Osmosis Membrane Module: The core component, utilizing the principle of semi-permeable membranes to allow water to pass under pressure while retaining most salts, organic matter, microorganisms, and other impurities. The desalination rate can reach 98% - 99% or higher.
- Distillation System
- Multi-Effect Distillation Unit: This is the key equipment. It typically uses triple-effect, quadruple-effect, or more evaporators. For example, in a triple-effect distillation unit, 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. The steam from the second effect, in turn, acts as the heat source for the third-effect evaporator. Through multiple evaporation-condensation cycles, impurities, microorganisms, and endotoxins are effectively removed, producing high-purity water for injection.
- Condenser: Used to condense the steam generated by the final-effect evaporator into liquid water. A cooling medium (such as cooling water) absorbs the heat from the steam to liquefy it. Common types include shell-and-tube and plate condensers.
- Storage and Distribution System
- Water for Injection Storage Tank: Typically made of 316L stainless steel, with the inner surface electropolished and passivated to reduce the leaching of metal ions. The tank is well-sealed, 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: Usually made of 316L stainless steel, it transports water for injection from the storage tank to the point of use. The pump must ensure stable flow, appropriate pressure, and be leak-free and contamination-free.
- Piping System: Primarily made of 316L stainless steel with electropolished inner surfaces, using welded or sanitary fittings for connections. Diaphragm valves are commonly used for their good sealing, ease of cleaning and sterilization, and prevention of microbial and impurity contamination.
2. Equipment Quality Requirements
- Material Selection: All components in contact with water for injection must be made of materials compliant with medical and pharmaceutical standards, such as 316L stainless steel, to ensure no harmful impurities leach into the water.
- Sterility Assurance: The overall design of the equipment must effectively prevent microbial contamination. For example, sterile storage tanks, piping, and valves are used, and regular disinfection and sterilization procedures maintain a sterile environment.
- Water Quality Compliance: The produced water for injection must strictly comply with relevant medical standards, such as national pharmacopoeias. For instance, conductivity is typically required to be low (e.g., less than 2 μS/cm), and bacterial endotoxin levels must be extremely low (less than 0.25 EU/mL).
3. Equipment Maintenance and Management
- Cleaning and Disinfection: Regularly clean all equipment components (e.g., storage tanks, piping, filters) to remove scale, biofilm, and other impurities. Sterilization methods include pure steam sterilization, superheated water disinfection, or chemical disinfectants to ensure a sterile state.
- Component Replacement and Repair: Regularly inspect and replace wear-prone parts, such as reverse osmosis membranes, filter cartridges, and valve seals. Promptly repair any equipment malfunctions to ensure normal operation.
- Water Quality Monitoring and Records: Use water quality monitoring instruments (e.g., conductivity meters, endotoxin detectors) to monitor water quality changes in real time and maintain records. Take immediate action if water quality abnormalities are detected.