Technical specifications
Product Overview
YJH VSD mediumpressure oilfree waterlubricated screw air compressor, customdeveloped for working conditions requiring mediumpressure, highpurity oilfree compressed air. The airend adopts reinforced pressurebearing stainless steel chamber. It delivers zerooil air complying with ISO 85731 CLASS 0 stably under 2.0–4.0 MPa, solving the industry problem of oil contamination from conventional piston mediumpressure compressors. Reinforced pressureresistant stainless steel chamber with custom sealing structure ensures stable operation without leakage under high pressure. Purewater isothermal compression controls airend temperature rise and extends service life. Intelligent protection system provides interlock alarms for overpressure, high temperature and low water level for safe and controllable production. Suitable for precision bottle blowing, highpressure testing, special processes, highend laboratories and other applications with strict requirements on both pressure and air purity. It avoids defects on precision products and invalid test results caused by trace oil
Air Intake & Filtration System
UNITED OSD’s new-generation rotor profile optimizes sealing and fluid-dynamic losses for outstanding performance.Dual-stage protection system with pre-air filtration + circulating water fine filtration. The intake assembly features optimized air passages for high-pressure service for smooth airflow. The main air filter uses high dust-capacity composite media with differential pressure monitoring to visually indicate filter clogging. The intake valve interlocks with the VSD control system to adjust intake volume synchronously with airend speed. An independent fine water filtration loop traps impurities and scale, protecting the high-pressure stainless steel meshing sealing surfaces. Modular filter cartridges allow easy removal and service.
Pre-filter: captures dust and particles to prevent scratches on stainless steel rotors and sealing surfaces, ensuring sealing reliability under high pressure.
Stable Class 0 air quality: upstream removal of solid contaminants reduces the load on downstream water-air separation, guaranteeing clean high-pressure oil-free air from the source.
Low-restriction air passage design: matched to intake requirements of medium-pressure models, low inlet resistance and reduced useless pressure loss.
Mechanical System
The core is a pressurereinforced allstainlesssteel waterlubricated singlescrew airend. Screws, star wheels, compression chamber, waterair separation chamber and all aircontact pipelines are made of stainless steel. Targeted at highpressure compression load of 2.0–4.0 MPa, the chamber wall thickness, connection structure and sealing pairs are specially reinforced for pressure resistance.Waterfilm sealing structure suitable for highpressure operation forms a stable sealing water film in the meshing gap with purified water to suppress highpressure internal leakage. Symmetrical doubleside starwheel meshing design counteracts axial thrust. Purified water acts as cooling, lubricating and sealing medium to achieve nearisothermal compression. The whole unit eliminates the entire oil circuit system. The frame adopts heavyduty reinforced structure together with highpressure damping components to resist vibration under heavy load.
Five Core Advantages
Truly oil‑free, pure water lubrication, isothermal energy saving, low maintenance, low noise & durable. Suitable for food, pharmaceutical, electronics, medical, precision machining and more.
【True Class 0 Oil‑Free】Oil‑free design from the source. No oil separator, no oil mist. Safe for sensitive industries such as food, pharmaceutical and electronics.
【Isothermal Energy Saving】Isothermal compression keeps low airend temperature, improves volumetric efficiency. VSD models deliver outstanding energy savings.
【Low Operation & Maintenance Cost】No costs for lubricant purchase, oil change or waste oil disposal. Only filter replacement and water top‑up, easy servicing.
【Clean & Corrosion‑Resistant】Airend rotors and air passages are stainless steel. Rust‑resistant, no risk of coating peeling contaminating air supply.
【Quiet & Eco‑Friendly】Low‑friction design reduces operating noise. Zero waste oil discharge, compliant with international environmental regulations, convenient for overseas factory acceptance.
