Working Pressure	2-4[bar]	29-58[psig]
Working Air Volume	19-100[m³/min]	671-3531[cfm]
Working Power	75-315[kw]	101-422[hp]

Advantages and Features:

• Can save over 30% electricity;
• The low-pressure air end can automatically adjust the internal compression ratio according to the working pressure, maintaining optimal energy efficiency within the 2-5 bar exhaust pressure range;
• In many industries such as chemical, glass, petroleum, textile, printing and dyeing, and ceramics, the working pressure required for compressed air is only 3-5 bar. However, these industries currently often use air compressors with 7-10 bar connected with pressure reducing valves to achieve low pressure; this is undoubtedly a significant waste of energy. To address this, UNITED OSD has developed low-pressure screw air compressors that directly output the low-pressure compressed air required by these industries; the compressors consume less energy, meet production requirements, and significantly improve users' production costs.

Mechanical System

Independently developed dedicated main unit

• Internationally leading molded liner, 4:6 gear ratio, fewer teeth for more air intake;
• Large rotor, low speed, long lifespan;
• The internal oil circuit of the main unit can precisely control the oil injection volume, helping achieve optimal performance for lubrication and cooling;
• SKF bearings adaptable to load changes, flexible, proven, durable, ensuring the lifespan of the main unit.

Low-Pressure Screw Air End Drive Chain

• The drive motor directly connects to the two-stage compression main unit without a coupling, making the drive chain maintenance-free and reducing energy consumption by 1%;
• The IP55 fully enclosed motor and main unit casing are integrated, effectively preventing pollutants such as metal particles, dust, and moisture from entering the motor and main unit, making the compressor performance more stable;
• The motor bearings use reinforced cylindrical + ball bearings, providing higher strength and reliability;
• Transmission gear machining precision up to aviation grade 6, multiple heat treatments and related processing techniques ensure all mechanical parts have superior surface hardness, ultra-high wear resistance, and yield strength;
• Independent oil supply system and precise oil filtration effectively ensure the stability and reliability of the entire gearbox during long-term full-load operation.

Intake and Filtration System

Pre-filter protective layer:

Prevents large dust particles, cotton, and other debris from entering the air compressor. Keeps the compressor interior clean. Strictly monitors the first pass of compressed air.

Particulate Air (HEPA) Filtration:

Heavy-duty air filtration system, with filtration accuracy up to 99.9% for particles larger than 3μm. Suitable for various heavy dust environments.

Dual large-diameter intake assembly design:

The pressure difference across all air paths is less than 0.2bar, significantly extending the service life of the air filtration system.

Optimized design of large-diameter intake valve:

Low energy consumption during no-load operation, cast aluminum material for more stable performance.

Optimized mold design for intake pipe:

High-strength rubber seal, firm and durable.

Oil Filter:

Donaldson oil filter, high clean filtration level, effectively protects the safe operation of the main unit bearings and extends the service life of the main unit.

Oil-Gas Separation System:

European design oil-gas separation element; fiberglass filter material; long life; moreover; no frequent replacement needed. The aggregate separation element works with the oil return device to effectively recover and circulate lubricating oil, preventing oil overspray and ensuring the compressor exhaust oil content is ≤2ppm.

Lubricating Oil:

UNITED OSD lubricating oil possesses many characteristics such as good oxidation resistance, high-temperature resistance, high flash point, and excellent thermal conductivity.

Cooling System

• The heat exchange design margin is 20%-50%, ensuring stable operation of the compressor in extreme environments and minimizing pressure drop.
• Standard motor variable frequency, accurate oil temperature control; further reduces air compressor energy consumption.

Features of Permanent Magnet Synchronous Motor (PMSM)

• Motor efficiency up to 96%, power factor 0.98, far exceeding Level 1 energy efficiency standards;
• High coercivity, high-temperature resistant permanent magnets ensure no demagnetization at 180℃ high temperature;
• Independent fan cooling ensures safe operation of the motor for long durations and at low frequencies;
• F-class insulation, 70K temperature rise design, suitable for high-temperature conditions of air compressors;
• Fully enclosed IP55 protection, protecting the clean internal environment of the motor and extending the lifespan of permanent magnets and insulation;
• Built-in temperature protection, protecting winding insulation and permanent magnets.

Permanent Magnet Synchronous Motor vs. Ordinary Asynchronous Motor

Efficiency:

Eliminates excitation system losses and improves efficiency.

Maintains under low-load conditions:

PMSM's energy efficiency is more than 9% higher than that of asynchronous motors, and remains constant as frequency decreases.

High starting torque:

The maximum starting torque of permanent magnet synchronous motors can reach up to 3 times the rated torque, while general asynchronous motors only have 1.6 times.

More stable control:

PMSM response time is less than 50ms. Gas production can be instantly adjusted within a wide range to precisely stabilize air pressure.

Features of UNITED OSD VFD Variable Speed PMSM Air Compressor

• Ultra-low temperature rise design ensures stable long-term low-frequency operation of the compressor;
• Adopts open-loop vector control system, offering faster control speed and more accurate speed regulation;
• The compressor unit can still operate when the frequency is reduced by more than 50%;
• Stable pressure, with pressure fluctuation precisely controlled within 0.01mpa; features soft start to avoid inrush current impact and reduce starting energy consumption.

Electrical System

New Generation Intelligent Controller	IoT Module	High-Quality Electrical Components
PLC+Touch Screen; User-friendly interface; Full monitoring of operating status; Smart operation; USB, COM interface, with upgradeable function.	Remote monitoring and maintenance; Remote operation, Data collection, Energy saving management.	Siemens electronic components; Variety of choices; Suitable for all climate conditions.

The UNITED OSD low-pressure series screw air compressor is a new type of compressor developed for energy saving, emission reduction, and environmental protection needs. It changes the traditional high-pressure compressor's method of supplying compressed air to air equipment after decompression, thereby saving energy. Currently, in the screw air compressor industry, the UNITED OSD's exhaust pressure can be as low as 1.2 bar, ensuring an exhaust oil content of less than 2ppm and providing clean and stable air supply. The enclosed cabinet with low-noise design is more environmentally friendly than piston compressors. Given that many industries do not require downtime, maintenance can be ensured during continuous operation; equipped with a fault alarm, it prepares users for emergencies, ensuring stable and reliable operation.