Learning from Mother Nature Aerzen Unveils New Compressor Generation

| Editor: Dr. Jörg Kempf

What on earth do a firefly, a leopard, a hummingbird, a porcupine fish and a kangaroo have to do with compressors? If you think that they have nothing in common, then we have news for you.

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To start with, we would like to put your mind at rest. There is no need to rewrite the wildlife books. However, it would appear that the engineers at Aerzen had a good look at what goes on in the wild kingdom when they were working on the company’s latest compressors, namely the Delta Screw Generation 5. The number 5 would appear to have a dual significance. This is the fifth generation of the Delta Screw series. The compressors also offer five main advantages, and this is where the engineers at Aerzen reached into nature’s bag of tricks.

1. Impressively economical: energy efficiency and reduced lifecycle costs

The model here is the firefly, which has an amazing energy efficiency of nearly 100 percent.

Aerzen screw compressors have asymmetric rotor lobes, which is a unique feature in the compressor market. A specially designed version with 3 + 4 lobes (VML) is available for low pressure applications up to 2 bar. The VM with 4 + 6 lobes is designed for higher pressure up to 3.5 bar. As a result, customers can select the most energy-efficient solution for the particular pressure range.

The compressors have two different pressure outlets for each rotor design to ensure optimal internal compression depending on the pressure and volume flow. Varying the compression ratio avoids over-compression and increases energy efficiency.

Aerzen claims that the improvement in the energy efficiency of the VM compressors is greater than 20 percent compared to other models. The company has also made engineering modifications to the accessories. Special noise suppression technology reduces pressure losses by up to 20 percent. Only motors with an EFF1 efficiency rating are fitted as standard equipment, adding up to 3 percent of additional energy savings.

2. Quiet operation: significant reduction in noise emissions

Model: The leopard is a relatively slow runner over long distances, but by nearly noiselessly sneaking up to within a few meters of its prey, it is able to catch faster animals.

The noise emissions of the new compressors have been reduced by about 6 dB(A) on average compared to the previous generation, and in some cases by even more. This significant reduction in noise can eliminate the need for costly special acoustic hoods.

3. Better safe than sorry: Atex certification keeps the sparks from flying

This defensive tactic is modeled on the porcupine fish. In case of danger, the porcupine fish inflates within seconds, and sharp spines which radiate out from the body provide perfect protection.

Atex certified spark suppression is another major benefit of the Delta Screw Generation 5. Compliance with the European Atex Directive (94/9/EC) is becoming an increasingly important consideration in all industries and applications. Aerzen compressors are designed and certified to meet Category 2 and 3 requirements for dust and gas zones.

The new compressors also feature a special explosion protection solution for pneumatic bulk goods applications. Specific air/dust concentrations can create ignitable mixtures in pneumatic bulk goods systems. EC Directive 1999/92/EG (Atex 137) requires additional protection for compressors, for example an external spark arrester. Aerzen has come up with an innovative solution. The new muffler contains no absorption material. Noise suppression is achieved solely by air redirection. The muffler was also certified as a spark arrester during practical testing, eliminating the need for an external spark arrester. Besides significantly enhancing system safety, this design reduces cost as well as pressure and energy losses.

4. High tech on a very small footprint: compact design saves space

The hummingbird serves as the model for compact design. It is one of the smallest birds in the world (some are smaller than 2½ inches). The hummingbird has a perfectly shaped beak and is very well adapted to its habitat.

The new Aerzen compressors are very compact, and they can be installed side by side without causing problems for service and maintenance personnel. The smaller footprint can reduce the customer’s investment in expensive machine room space.

5. Keep it simple: user-friendly and low maintenance

The model is the Australian kangaroo, which carries its joeys around with it in a comfortable pouch for the first eight months of their life.

The compressor engineers paid particular attention to user-friendly design and lower maintenance starting with the installation phase. The compressors can be moved to the place where they will be installed with a pallet jack or forklift. An integral service pack including jack, funnel and initial filling of oil is provided for installation and service. The compressors are operated from the front, and all components that require maintenance are easily accessible. The new oil system allows the user to check the oil level when the machine is running, eliminating the need to shut down the machine and interrupt the process or production line. The patented belt-drive system reduces the need for maintenance which in turn has a positive effect on lifecycle costs.

The drive motor is mounted on a hinged support, and the weight of the motor maintains the proper tension on the belt. This eliminates the need to readjust the tension even after many hours of operation. With this design, the compressor performance rating can be modified to accommodate new system requirements (pressure/volume flow) by simply replacing the V-belt pulleys.

Other advantages of the new generation include the elimination of absorption material (food purity), mechanical fans, Class 0 certification (oil-free), PED, ASME, RTN and China License approval.

The Aerzen compressors are designed to convey air and neutral gas. Belt-driven Delta Screw Generation 5 compressors are currently available for pressure, vacuum and nitrogen applications with DN 125 – DN 200 nominal diameters. Because the products feature a modular design, all compressors and motor sizes which are suitable for a nominal width range can be used to configure a belt-driven system. This makes it possible to put together a system which is the best solution for the particular application and to make modifications at a later date if necessary. Generation 5 customers will have seven sizes to choose from (the VM 37 R and VML 40 R are currently in the development pipeline) for suction volume flows between about 270 m³/h and 2600 m³/h and pressure up to 3.5 bar. The VML unit can be used to produce about 70 percent vacuum (0.3 bar abs), and a special version is available for vacuum up to 85 percent (0.15 bar abs). The entire Delta Screw range includes 15 sizes for volume flows up to 15,000 m³/h.