Two-Stage Screw Compressor | Water Cooled Air Compressor

ELGi is one of the very few compressor companies to design and manufacture oil-free airends. The compressors are engineered to deliver maximum uptime and reliability with in-house oil-free technology. ELGi’s unique eta-V rotor design reduces pressure losses and increases stage efficiencies, leading to an optimised compressed air system.

The Optimised component layout of the ELGi OF series machine provides easy serviceability with reduced service time. Incorporating superior safety norms, the compressors have not only low energy losses and low air outlet temperatures but are also highly reliable and compact. ELGi oil-free air compressors have all these advanced features integrated into one simple design that drives maximum Reliability and Uptime. Choose ELGi and discover the benefits of Oil-free electric air compressors engineered for superior performance, reliability, and efficiency.

WHY CHOOSE ELGi OIL-FREE SERIES?

Class 0 oil-free air

Our two-stage oil-free compressor series has consistent oil-free air meeting ISO8573-1 Class ‘0’ standards. Food grade coating is done on parts where the air contacts the metal surface inside the compressor, ensuring consistent oil-free compressed air without metal debris. Pipes have special e-coating, which ensures consistently clean and oil-free compressed air, along with optimised rotor clearances, which ensure consistent compressed air delivery

Indigenously designed and manufactured airends

ELGi is one of the very few air compressor companies to design and manufacture oil-free airends. With our in-house oil-free technology, the Class ‘0’ air compressors are engineered to deliver maximum uptime and reliability. ELGi’s unique eta-V rotor design reduces pressure losses and increases stage efficiencies, leading to an optimised compressed air system

Airend coating for efficiency and long-term reliability

Our airend rotors and housing are coated with a proprietary coating to resist corrosion and endure high temperatures up to 250-degree C. This result in optimum performance with no loss in efficiency.

Flexible design allowing for air-cooled and water-cooled requirements

Our Oil-Free Series have Cupronickel coolers with a water-in-tube system, specially designed for a temperature difference of max. 8 degrees C, having the least fouling factor of its kind with the best thermal efficiency.

Best-in-class warranty

ELGi comes with Uptime Assurance which is all about giving customers peace of mind by offering the industry leading warranty which warrants that its product and the components will perform the purpose and function for which they are designed and intended for the periods of time indicated when used, serviced and maintained in accordance with ELGi's instructions and specifications.

Best-in-class maintenance cost

With our Rack and Pinion capacity control system in the Oil-Free Series, there is no maintenance required for over one million cycles. This exceptional durability is further enhanced by the long-life air seals and oil seals, which significantly reduce wear and tear.

Advanced Cooling System

The integrated aftercoolers and inter-stage cooling systems enhance thermal efficiency and help maintain consistent performance, thereby protecting internal components and extending the overall lifespan of the compressor. Superior heat dissipation also contributes to energy efficiency and minimises the risk of overheating.

Effective Lubrication for Critical Components

The OF Series incorporates a precise and reliable lubrication system that ensures smooth operation of bearings and mechanical parts without contaminating the air. This guarantees low wear and long service intervals while maintaining oil-free compressed air delivery for sensitive applications such as pharmaceuticals, food, and electronics.

Efficient Low Pressure System

The OF Series includes a robust low-pressure system that supports auxiliary operations without overloading the primary compression stages. This thoughtful integration allows for optimal compressed air management and energy conservation. A low-pressure air compressor system is ideal for applications that require different air pressure levels within the same facility, offering flexibility and efficiency in a single package.

Pharma

Maintaining a sterile environment during pharmaceutical manufacturing is crucial. Two-stage water-cooled compressors are required to ensure pharmaceutical production meets high quality standards. These compressors provide oil-free compressed air, reducing the danger of contamination in processes like drug formulation, packaging, and other key pharmaceutical applications.

Food and Beverages

Electric oil-free screw air compressors are used in the food and beverage industries, where product safety and hygiene are critical. Oil-free two-stage air compressors produce clean, uncontaminated compressed air that meets food-grade standards throughout procedures such as packaging, bottling, and food handling.

Textiles

Electric oil-free rotary screw air compressors are critical in the textile sector for maintaining a clean, oil-free compressed air supply. In this sector, two-stage water-cooled compressors help to maintain compressed air quality, preventing pollution that could impact delicate textile manufacturing processes like spinning and weaving.

Electronics

In the electronics industry, where precision and purity are critical, two-stage oil-free air compressors are essential. These compressors provide a consistent supply of contaminant-free compressed air, protecting electronic components throughout industrial processes such as PCB assembly and semiconductor manufacture.

Air Separation

Industries that use air separation, such as the manufacturing of industrial gases, rely on two-stage water-cooled compressors to achieve strict purity requirements. These compressors provide a consistent and stable source of oil-free compressed air, which improves the performance of operations such as cryogenic distillation in air separation plants.

Power & Energy

In power plants, especially those using gas turbines or combined cycle systems, high-quality compressed air is essential for control systems, ash handling, and instrumentation. ELGi’s oil-free compressors ensure reliable, contamination-free air to maintain plant efficiency and uptime.

Process Industries

In chemical and petrochemical plants, compressors must withstand demanding conditions while ensuring product purity and operational safety. ELGi’s oil-free technology eliminates the risk of process contamination and supports critical applications like reactor purging and instrument air supply.

Semiconductor

Semiconductor manufacturing requires ultra-pure, particle-free environments. ELGi’s oil-free air compressors help maintain the cleanroom standards necessary for lithography, wafer cleaning, and chip assembly, ensuring precision and reliability.

Cement Industry

In cement manufacturing, compressed air is essential for blending, conveying, and packaging processes. ELGi’s robust, oil-free compressors withstand dusty and high-load environments while ensuring clean compressed air for equipment operation and pneumatic controls.

Iron & Steel

Steel plants require high volumes of compressed air for blast furnaces, material handling, and cooling systems. Two-stage compressors offer durability and efficiency, delivering uninterrupted performance in harsh industrial conditions.

Automobile Manufacturing

Precision painting, robotic operations, and pneumatic tool usage in auto manufacturing demand clean, dry air. ELGi’s oil-free compressors reduce rework, protect sensitive systems, and enhance the quality of end products.

Dairy Industry

Oil-free air is essential in dairy operations, from milk processing and packaging to cleaning systems. ELGi’s compressors ensure contamination-free air to maintain product purity and comply with stringent hygiene norms.

Distilleries

In distilleries, compressed air is used in fermentation control, bottle filling, and CIP (clean-in-place) processes. ELGi’s oil-free solutions safeguard product quality by preventing any risk of oil contamination, ensuring purity from grain to glass.

Low Pressure Air Compressor Applications

Certain industries rely on low-pressure air to maintain optimal process conditions without overexerting energy or equipment. ELGi’s low-pressure air compressors are ideal for:

Fermentation

In biopharmaceuticals and food industries, low-pressure compressed air helps maintain aerobic conditions critical to microbial activity and production yields.

POY (Partially Oriented Yarn) Industries

These applications use low-pressure air for yarn spinning and cooling processes, ensuring product consistency and efficiency.

Aeration

Used in water and wastewater treatment plants, low-pressure compressed air is essential for promoting biological activity and maintaining oxygen levels in aerobic tanks.

Pneumatic Conveying

In industries like cement, grain, and food processing, low-pressure systems transport bulk materials gently and efficiently through pipelines without causing damage or contamination.

Air Cooled & Water Cooled Compressors: ELGi's Guide to Choosing the Right One

One of the most crucial considerations you will have to make when purchasing an industrial air compressor is whether to go with an air-cooled or water-cooled type. Both have advantages and disadvantages, and therefore the choice depends on your individual requirements and operating environment. ELGi, a globally trusted manufacturer of air compressors, provides a diverse selection of air-cooled and water-cooled choices to meet your needs.

Air-Cooled Compressors

Air cooled air compressors are the most common type, utilising a fan and radiator to dissipate heat generated during the compression process. They're:

Simple and easy to maintain

With fewer components than water-cooled systems, air-cooled compressors are less prone to breakdowns and require less maintenance.

Cost-effective

They have a lower initial purchase price and lower operating costs as they don’t require water treatment or a dedicated cooling system.

Energy efficient

Though they consume slightly more power than water-cooled models, air-cooled compressors can recover heat loss and utilise it for space heating or other applications.

Water-Cooled Compressors

Water-cooled air compressors use an external liquid coolant loop to extract heat from the compressed air. They offer:

Higher efficiency and performance

Water-cooled air compressors can operate at higher temperatures and pressures, leading to increased efficiency and productivity.

Reduced noise levels

The external cooling system helps minimise noise pollution, making them ideal for sensitive environments.

Compact design

Water-cooled screw compressors can be smaller and more compact than air-cooled models for the same compressed air output.

FREQUENTLY ASKED QUESTIONS

How does a two-stage screw compressor differs from a single-stage compressor?

Unlike single-stage compressors, two-stage screw compressors compress air in two successive steps, resulting in higher efficiency and reduced operating temperatures. ELGi’’s compressors ensure optimal performance and durability.

Where can I find ELGi two-stage compressors for sale?

ELGi’’s authorised distributors and dealers offer a range of two-stage screw compressors for sale. You can find local dealers or contact ELGi directly for assistance in locating a reliable supplier.

What makes ELGi’s OF Series suitable for critical applications?

The OF Series offers 100% oil-free compressed air with ISO 8573-1 Class 0 certification, making it ideal for pharmaceutical, food & beverage, textile, and electronics industries where compressed air purity is non-negotiable.

Does the OF Series require high maintenance?

No. The OF Series is designed with minimal maintenance in mind. Components like the long-life air/oil seals, robust cooling systems, and direct drive configurations reduce the need for frequent service and ensure long-term reliability.

What are the key maintenance checks for the OF Series?

Regularly inspect and clean the air filters, check oil levels in the gearbox, monitor the condition of seals, and ensure proper functioning of the cooling system. Periodic checks of the air-end and control panel are also crucial.

Do oil-free compressors require lubrication?

Yes, while the air-end is oil-free, the gearbox and certain bearings in the OF Series still require proper lubrication. Use only ELGi-recommended lubricants to ensure performance and longevity.

How can I reduce downtime during maintenance?

Follow a preventive maintenance schedule, keep essential spares on hand, and rely on ELGi’s trained service personnel or AMC plans to ensure timely service with minimal disruption.

How Does a Two-Stage Oil-Free Air Compressor Work?

ELGi’s OF Series two-stage oil-free air compressors are engineered to deliver 100% oil-free, high-quality compressed air with maximum reliability and efficiency. These compressors operate in two sequential stages of compression to achieve higher pressures while maintaining lower operating temperatures.

Stage 1: First Compression
Ambient air enters through a high-efficiency inlet filter and is compressed in the first-stage airend without any oil contamination. This compressed air then passes through an intercooler, which reduces its temperature, enhancing compression efficiency and reducing the load on the second stage.

Stage 2: Second Compression
The cooled, partially compressed air enters the second-stage airend for further compression. Post-compression, the air passes through an aftercooler to reduce moisture and temperature before it is delivered to the application.

Oil-Free Design
The OF Series utilises precision-engineered, non-contacting rotors with a proprietary ULTRA COATING™ to eliminate oil from the entire process. This ensures Class 0 certified air, making it ideal for industries like pharmaceuticals, food, electronics, and textiles.

Cooling System
The compressors feature advanced cooling options, including air-cooled and water-cooled configurations, ensuring optimal operating temperatures, reducing wear and tear, and improving compressor lifespan.

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