Structural characteristics of twin-screw compressor

As a representative of volumetric compression equipment, the core structure and operation mechanism of twin-screw air compressor reflect the design concept of high efficiency and stability. The following from the key components, technical characteristics and design advantages of three aspects:

composition of 1. core components

1. yin-Yang screw rotor system
   • double rotor meshing: It is composed of a convex male rotor and a concave female rotor precisely meshing. The male rotor is directly connected to the motor drive shaft, and the female rotor realizes reverse synchronous rotation through synchronous gears or oil film pressure.
   • Asymmetric profile design: The rotor tooth surface is processed with special curved surface to form involute-cycloid composite line to ensure uniform meshing clearance and volumetric efficiency of 80%-85%.
   • Material Process: The main material is ductile iron QT500-7, the surface of the phosphating treatment or nitriding treatment, the hardness of HRC55 or more, wear resistance increased by 3 times.
2. Precision bearing combination
   • radial support: Using four-row cylindrical roller bearings, the rated dynamic load is up to 50 times the weight of the rotor, ensuring the stability of high-speed operation at 3000-30000rpm.
   • axial positioning: Equipped with a two-way thrust bearing group to bear the axial thrust generated by the exhaust end pressure, and the axial clearance is controlled within the range of 0.02-0.05mm.
3. slide valve adjusting mechanism
   • capacity regulation: The hydraulic cylinder drives the slide valve to move axially, changes the effective working length of the compression chamber, and realizes 10%-100% stepless speed regulation.
   • Pressure control: The spool valve position sensor feeds back the adjustment signal in real time, and the pressure fluctuation is controlled within ± 0.02MPa.
4. oil circuit circulation system
   • oil and gas separation: Three-stage separation design (cyclone separation + screen filtration + coalescing filter element), exhaust oil content ≤ 3ppm.
   • temperature control system: The oil cooler adopts plate heat exchange structure and cooperates with temperature control valve to maintain the oil temperature in the best working range of 50-65 ℃.

Technical characteristics of 2. structure

1. forced gas transmission mechanism
   • the continuous meshing of the yin and yang rotors forms a closed chamber, the gas delivery does not rely on the exhaust valve, and the theoretical gas delivery is only related to the speed and the geometry of the rotor, realizing the real forced gas delivery characteristics.
2. dynamic balance design
   • the vibration intensity of the whole machine is ≤ 2.8 mm/s(ISO 10816-1 standard), the dynamic load of the foundation is reduced by 60%, and the installation without anchor bolts is supported.
3. Sealing technology integration
   • the shaft end adopts double-end mechanical seal, the leakage is less than or equal to 0.5 mL/h, and the matching seal flushing system can withstand the maximum exhaust pressure of 2.5MPa.

Analysis of 3. design advantages

1. high reliability architecture
   • the moving parts are reduced by 40% (compared to the piston type), the wearing parts are limited to bearings and seals, and the overhaul period is extended to 4-80000 hours.
2. Wide working condition adaptability
   • the internal volume ratio is fixed (Vi = 2.6-3.5), and the external pressure ratio is matched through the slide valve adjustment to adapt to the ambient temperature change from -30 ℃ to 50 ℃.
3. Ease of Maintenance
   • the modular design allows the rotor assembly to be disassembled as a whole, reducing the maintenance time to 4 hours (12 hours for traditional models).
   • The intelligent diagnosis system can monitor 18 parameters such as bearing temperature and vibration spectrum, and give early warning of faults 200 hours in advance.

4. typical application scenarios
based on the above structural characteristics, screw air compressors show significant advantages in the following areas:

• industrial Manufacturing: Provide stable air source for pneumatic tools and automatic production lines, with pressure bandwidth covering 0.2-1.3MPa.
• Refrigeration Engineering: The evaporation temperature of -40 ℃ is realized in the chiller, and the energy efficiency ratio (COP) is more than 3.8.
• Special conditions: Through surface coating treatment, it can be applied to harsh environments with dust content of 50 mg/m & sup3.

Screw air compressor through the precise rotor system, intelligent adjustment mechanism and efficient sealing technology, to build a high reliability, wide adaptability of the compression platform. Its structural innovation not only improves the efficiency of equipment operation, but also reduces the cost of the whole life cycle, and becomes the core equipment of modern industrial gas source system.