ELGI Oil-free Screw Air Compressor

 Hitachi is a world-class manufacturer of oil-free screw compressors for industrial applications. Continuous upgrade of technology has resulted in superior compressors that provide high-quality compressed air with minimal running costs. Elgi is now licensed to manufacture the world-renowned SDS series of Hitachi compressors, marketed in India as Elgi NH Series Compressors.

Features:

Efficient:
The compressor package is the most efficient in the market, thanks to the patented Hitachi NH profile rotors manufactured in a state-of-the-art plant in Japan . Durable:
High precision bearings, fine filters and optimally designed lube oil circuit ensure enhanced life. Quiet:
The specially designed compact canopy with suitable sound absorbing media ensures quiet operation.  

Maintenance-friendly :
The hinged powder-coated panels of the sound-proof cover add aesthetic valve and make the compressor easy to inspect and maintain.

High Performance with the efficient NH profile rotor:
The NH profile rotor has been developed after a thorough analysis of the thermal deformation of screw rotors in operation. The leakage of air has been dramatically reduced by maintaining the optimum gap between screw rotors in operation. As a result, the Elgi NH Series Compressor offers 5% greater adiabatic efficiency when compared to a conventional compressor. This reduces operating costs. A newly developed resin coating (patent pending) has been applied to the surface of the rotor, significantly increasing its durability. Precision profile measuring technology and highly accurate grinding technology are other factors that contribute to the superior quality of the rotor.

Maintenance cycle of 50,000 hours or 6 years with long-life bearings:
Maintenance cycles of compressors vary depending upon the life of the roller bearings that support the screw rotors. Several factors play a role in extending bearing life. The development of NH Series drew on the latest analysis technology and lubrication theory. These guidelines were applied to the selection of the lubricating oil, improving the quality of the oil, determining the shape of the injection nozzle, even in the selection of materials for the bearings with a view to enhancing dimensional accuracy. Long life was realized by controlling all the components in optimal conditions. The latest technologies are reflected in features such as high-endurance floating seals and a newly developed resin coating. The result is a dramatic reduction in maintenance costs. The regular maintenance cycle of 35,000 hours or four years in the case of conventional compressor has been lengthened to 50,000 hours or six years in the NH Series.

Capacity control device:
Two-step control - Capacity is adjusted with two-step control. Loading and unloading are controlled based on increases and decreases in air consumption detected by discharge pressure changes. The capacity control valve is a simple structure with a hydraulic piston driving a rack and pinion. This ensures fail-safe switching without malfunctions caused by rust.

Shaft seal:
Minimal air leakage-Long-life floating seals enable the compressor to be operated for a extended time with minimal leakage of air. Visco-type seals and labyrinth seals are also used in the bearing section, providing a double barrier that prevents oil mist from entering the compression chamber.

Air cooler:

Designed with cooling water quality in mind.
The air cooler has been designed based on exhaustive studies on structural design and material selection, which take into account the fact that industrial water is liable to cause scaling. The inner fin tubes are made of copper nickel alloy for enhanced resistance to corrosion and heat. The widely spaced tubes allow easy removal of scaling. The fluid passage in the drain separator section was developed after analyzing the behaviour of drain mist. This design improves reliability.

User-friendly Diagnostics:
Solid state MIMIC Electronic Annunciation Panel gives fault indication for easy maintenance and diagnosing the following defects:

• Motor Overload and Reverse Rotation
• High Inter Stage Air Pressure and Air Temperature
• High Oil Temperature and Low Oil Pressure
• High Discharge Air Pressure and Air Temperature
• High Blow Off Air Pressure and Low Water Pressure

Engineering Data: