Oil-free screw compressors

Aerzener's Delta Screw single stage, oil-free screw compressor of size VM 45 now operates more energy-efficiently. the compressor offers differential pressure up to 3.5 bar, volume flow up to 3,200m³/h, driving power up to 250kW. Energy savings of up to 6% could be proven depending on the pressure ratio or the vol-ume flow - an impressive value in this category. Further revised types of the Delta Screw series will follow, step-by-step.
The energetic improvement is the result of many con-structive optimisations. Instead of suctioning the air to be compressed from inside the acoustic hood, cooler outside air is now sent through an intake channel directly to the intake filter. This improves the specific performance of the plant considerably.  

In addition, optimised inflow channels and an innovative pressure-side silencer with improved fluid dynamics and no absorption materials help minimise pressure loss significantly. This vertically arranged five-chamber reactive silencer is the result of years of research of the Aerzen development team (applied for patent). The silencer out-put could be reduced to less than 80dB(A), depending on the kind of operation, as a result of optimised cross sections and idealised lengths of chambers. Moreover, by using two compensators, the system is also 100% stress-free. In future, this discharge side silencer will also be de-signed as spark arrester according to ATEX Directive 137 for explosion proof plants (EU Directive 1999/92/EG).

Up to now, the fan for cooling the interior of the acoustic hood was positioned on the compressor shaft and driven by the main driving motor, and for this reason it had to be designed to the lowest speed of this motor. From now on, the fan will be equipped with a separate electric motor. For this reason, it can be constructed in a smaller size, positioned particularly efficiently, be controlled tempera-ture-dependent, if necessary be operated in run-down, and designed to be energy-saving. The cooling air for cooling the lubricating oil of the bearing is now fed in directly from the outside via an inlet channel - a detail which also improves the economy of a compressor just as any temperature reduction does. All Aerzen units are already provided with energy-saving IE3 motors, in spite of the fact that they will be required by law only from 2015.  

The flexible concept of series Delta Screw additionally permits customised special solutions, as for example special motors, acoustic hoods for special ambient conditions or special instrumenta-tions. The series is easy to service and maintain. The service life of the lubricating oil for the bearing of 16,000 operating hours, which corresponds to maintenance intervals of 16,000 operating hours, is another positive contribution.