High quality air
January 1st 2004 IP&E exclusively reveals that CompAir has, alongside Atlas Copco, also launched a new oil free, water-injected compressor this month
Compressor manufacturer CompAir has extended its oil-free offering with the introduction of a new range of water-injected single screw compressors. Designed for applications where there is a need for high-quality active air air that comes into direct contact with the process it serves the new DH-Series offers a cost-effective oil-free solution for users looking for compressors in the smaller size ranges. The series is launched with 15, 22 and 37kW models, with plans to add variable speed models and extend the range to 75kW.
Claiming the lowest specific energy consumption in its class, the DH-Series offers energy efficiency and low operating costs. Product manager Andy Pulley comments: In active air applications, quality of the air is key. High technology industries in particular, including precision engineering, pharmaceutical, food and drink, electronics, chemicals and healthcare, all demand higher quality air. They are also looking for the lowest ownership and operating costs. The DH single-stage water-injected rotary series is not only the most efficient range of oil-free rotary products available, it offers reduced energy and maintenance costs and hence a lower life time cost than any other compressor in its size range.
At the heart of the DH-Series is a single stage, single screw water injected compression element. It has a bronze single six-flute main rotor with two carbon-fibre composite eleven-tooth gate rotors. The compression element is designed to deliver twelve pulses of air per revolution, compared to six pulses for a conventional screw. This, together with the elimination of metal-to-metal mating parts, offers low vibration and noise levels.
During the compression cycle, atmospheric air enters the compression element and fills the flutes of the main rotor. The gate rotors engage with the flutes and form two compression chambers, above and below the main rotor. The gate rotors automatically follow the rotation of the main rotor, reducing the volume in the flutes and compressing the air along the compression chambers. Purified water injected into the compression element seals, cools and lubricates the process. When the flutes align with the discharge port, the compressed air and water mixture is discharged from the compression element and the water is separated from the compressed air in a vessel.
Fully integrated into the package is a water purification system that uses reverse osmosis membrane filtration to provide high quality injection water. This removes dissolved salts, metals, minerals and organisms and ensures reliable and trouble-free operation. This purified water enhances efficiency by providing superior cooling and near isothermal compression. With only a 15C temperature rise across the compression element, there is no need for a final air cooler, which reduces pressure losses and hence energy consumption.
The fully integrated package includes the air-cooled water cooler, water purification, full silencing for low noise levels, and a DELCOS 3100 control system. This simplicity of construction significantly reduces maintenance costs, with a service interval of 4000 hours and servicing limited to changing the filter elements. Andy Pulley: A major advantage of this design is that fact that not only is the air produced totally oil free, there is no oil used in the compressor at all. The bearings are greased and sealed for life, so there is no danger of contamination and no environmental costs associated with oil disposal. More articles from The Bright Consultancy Limited: | 
