Whether you're in manufacturing, pharmaceuticals, or construction, understanding the key features of these compressors can help you choose the best one for your application. This guide aims to simplify the process, drawing on Atlas Copco's extensive experience in compressed air systems.

A rotary screw compressor uses two rotors (helical screws) to compress air, differing significantly from reciprocating air compressors which utilize pistons. As the screws interlock, they reduce the volume of air, increasing its pressure. This design allows for continuous operation, making rotary screw compressors ideal for applications requiring a constant air supply.

Their benefits? In addition to the efficiency, reliability and versatility, rotary screw air compressors have many other advantages: 

• Their noise output is low and their physical footprint small. That means you can install them in more places.

• Unlike piston compressors, they don’t need cool-down periods. This allows them to operate continuously and they do not require a lot of maintenance. 

• In addition, oil-lubricated rotary screw compressors feature a low oil carry-over of as little as 3 ppm.

• Finally, over their expected service life of 10 years or more, you don’t have to worry about a loss of capacity. 

First of all, it is essential to determine whether an oil-free or oil-injected rotary screw compressor best suits your requirements. Choosing between oil-free and oil-injected rotary screw compressors depends on your air purity requirements. Oil-free compressors provide high-quality air, which is essential for industries like food processing and pharmaceuticals. Oil-injected models are more common and cost-effective, suitable for general industrial use where air purity is less critical.

Now that you've already selected between an oil-injected and an oil-free compressor, the next step is to choose the drive type for your air compressor. Atlas Copco offers rotary screw compressors with belt or gear drives. Belt-driven compressors are cost-effective and easy to install, operate and maintain, ideal for smaller operations. Gear-driven models are quieter and more efficient, suitable for larger, more demanding applications. Their initial investment cost is a little higher. However, because they are more efficient and maintenance free, compressors with gears are less expensive to operate. This will allow you to quickly recoup that higher cost. 

Fixed-speed, dual-speed, and variable-speed rotary screw compressors are the common options for various applications. 

It is often said the choice between fixed-speed and variable-speed rotary screw air compressors typically depends on your air demand. Fixed-speed compressors run at a constant speed, best suited for applications with steady demand. Variable speed drive (VSD) compressors only when you have fluctuating demand.

Despite such common perceptions, fixed-speed compressors aren't necessarily the ideal choice for constant air demand. VSD compressors are also perfectly capable of handling such scenarios by dynamically adjusting their speed to match air demand, delivering higher efficiency and energy savings for both stable and fluctuating needs. Ultimately, the decision boils down to budget constraints rather than specific application requirements. 

A third option exists, offering greater energy efficiency than fixed-speed compressors at a lower investment cost than VSD compressors. Dual-speed technology optimizes free air delivery at any given pressure setting. While it requires a higher initial investment compared to fixed speed, it offers increased flexibility and is well-suited for applications requiring high flow at various pressures. 

In conclusion, when considering fixed-speed, dual-speed, and variable-speed rotary screw compressors, a VSD compressor emerges as the superior choice for applications with both variable and steady demand. Its efficiency benefits not only your bottom line but also the environment in the long term.

Selecting the correct size for your rotary screw compressor is crucial. It's essential to consider the required flow of compressed air as the primary factor in sizing. An undersized compressor won't meet your air demands, while an oversized one wastes energy. Atlas Copco's offers a variety of sizes to suit different needs, ensuring efficient operation and energy savings.  

Let's take a look at the G 2-7 range, the smallest type of compressor at Atlas Copco. Compared to piston air compressors, which are traditionally used by operations with a limited compressed air demand, they offer many advantages. They are more efficient, which reduces your costs and environmental footprint. Besides, they can run around the clock so they can handle an increased demand better. Finally, fixed-speed rotary screw compressor lower the oil content in your compressed air system, a feature that a reciprocating compressor may struggle to match.

Atlas Copco provides a comprehensive range of rotary screw air compressors, including the VSD, VSD+, VSDs, G, GA, and GA+ series. Each series caters to different requirements, from basic needs to demanding industrial environments, ensuring there's an Atlas Copco compressor that's right for your business.

Atlas Copco revolutionized the industry four decades ago with variable speed drive (VSD) technology, adjusting motor speed according to compressed air demand, significantly reducing energy consumption and costs. Now in their third generation (GA VSDˢ), they have raised the bar in every metric. This includes efficiency and sustainability, reliability, connectivity and ease of operation.

• G VSD: Our G oil-injected rotary screw compressors are designed for reliability and efficiency. Will operate continuously in the harshest environments, avoiding costly downtime and production delays.
• GA VSD+: Our market-leading GA oil-injected rotary screw compressor delivers outstanding performance, high productivity and low cost of ownership – even in the harshest environments.
• GA VSDs: When you need the best, choose VSDs. With energy savings of 60% on average compared to fixed-speed models, the GA 5-37 VSDs is the most energy-efficient compressor on the market. It also raises the bar in performance, reliability and connectivity to support your sustainability and productivity goals – now and in the future.
• GA FLX:  For those hesitant to adopt VSD technology, Atlas Copco has introduced dual-speed compressors, offering a balance between cost and energy savings. The GA FLX series combines the affordability of fixed-speed compressors with the energy savings of VSD technology, featuring two speeds to adapt to changing demand, offering up to 20% energy savings.

Prvo, pogledajmo njihove prednosti: pored efikasnosti, pouzdanosti i prilagodljivosti, vijčani vazdušni kompresori imaju mnoge druge prednosti.

Nivo buke na izlazu je nizak, a zauzimaju malo prostora. To znači da ih možete instalirati na više mesta.

Za razliku od klipnih kompresora, njima nisu potrebni periodi hlađenja. Ovo im omogućava da rade neprekidno 24 sata - i ne zahtevaju mnogo održavanja.

Pored toga, rotacioni vijčani kompresori s uljnim podmazivanjem karakteriše mali prenos ulja od samo 3 ppm.

Konačno, tokom njihovog očekivanog radnog veka od 10 godina ili više, ne morate da brinete o gubitku kapaciteta.

Nakon što ste suzili izbor na kompresore sa fiksnom brzinom, sledeći korak je izbor između bezuljnih modela ili modela sa ubrizgavanjem ulja.

Razlika je u tome što ovaj drugi unosi novi zagađivač u proces kompresije. Stoga biste izabrali bezuljni kompresor  ako je parametar prisustva ulja i uljnih para važan – na primer, ako vaša industrija podleže standardima za čistoću vazduha. Ovo uključuje farmaceutsku industriju, sektor hrane i pića i proizvodnju poluprovodnika.

Ovde je bezuljna tehnologija bolja alternativa nego korišćenje modela sa ubrizgavanjem ulja a zatim filtriranjem zagađivača.

Ako je kvalitet vazduha manje važan, na primer ako vam je potreban kompresor za napajanje pneumatskih alata, onda će model s ubrizgavanjem ulja obično biti zadovoljavajući.

Atlas Copco nudi vijčane kompresore fiksne brzine sa dve vrste pogona. U zavisnosti od namene, svaki od njih ima različite prednosti:

- Remenski (kaišni) pogon: Vijčani kompresori fiksne brzine sa kaišnim pogonom su veoma robusni. Oni su najjeftiniji i jednostavni za instalaciju, rad i održavanje. Iz svih ovih razloga, oni su popularan izbor za manja postrojenja.

- Zupčasti (pomoću zupčanika) pogon: Zupčasti pogon čini rad kompresora tišim. To znači da ga možete instalirati na više mesta bez kršenja standarda za nivo buke. Početni troškovi ulaganja su u ovom slučaju malo veći. Međutim, pošto su efikasniji i ne zahtevaju održavanje, rotacioni vijčani kompresori sa zupčanicima su jeftiniji za rad. Ovo će vam omogućiti da brzo nadoknadite veći trošak