Mechanical Technology July 2016

⎪ On the cover ⎪

Compressor Technique expands

Atlas Copco Compressor Technique in South Africa is expanding its offering of industrial compressors, nitrogen and oxygen generators, air treatment equipment, blowers and low-pressure compressors to better meet application- specific needs in the local market. MechTech talks to business line managers Charl Ackerman and Pieter van Wyk.

A tlas Copco is continuing to expand its premium GA, GA+, GA VSD and GA VSD+ com- pressor ranges, most recently with the inclusion of 200 and 250 kW VSD (variable speed drive) versions of its GA oil-injected, screw compressors. “We had a gap in our VSD range between 160 and 315 kW. We have now closed this gap with the inclusion of VSD versions for our GA 200 and GA 250 models,” Van Wyk reveals, adding: “while VSD com- pressors are not widely used in mines, we have seen immediate success with these energy conscious clients.” Operating at medium to high pressure – 5.5 bar up to 13 bar – the GA range is ideal for the manufacturing sector, typically energising robots, actuators and clamps on automatic production lines. Talking about the role of VSD versions, Van Wyk explains that if a compressor can be run at maximum capacity, 24/7, then the addition of a VSD is not neces- sary. “But if the compressors are regularly run at below maximum capacity, then it is usually more efficient to use a VSD

to match the compressor’s speed to the compressed air demand,” he explains. Hence the need for the two new addi- tions, so that compressors with smaller motors can be used for 200 and 250 kW VSD applications. “These additions give us energy efficient VSD compressor op- tions spanning the power range all the way from 7.0 to 315 kW,” Van Wyk tells MechTech . “By combining a fixed speed compres- sor with a second VSD compressor, one can cater for both variable demand and, at the same time, provide a level of re- dundancy for situations when one of the compressors needs to be serviced. And if full redundancy and variable flow are required, we recommend two fixed-speed compressors plus a VSD, with the two fixed speeds being alternated to supply minimum continuous demand and the VSD providing the variable top-up flow,” he adds. On the ultra-high efficiency side, Ackerman says that the permanent magnet VSD+ range of compressors is also being extended. “Our GA VSD+ compressors have been completely re- designed to make best possible use of Atlas Copco-patented permanent magnet (PM) motor and drive train technology. “When used on a variable speed application, VSD+ compressors offer up to 50% better energy ef- ficiency as compared to their fixed speed siblings,” he assures. In addition, permanent magnet motors and the new compressor design enable full speed operation at better efficiencies than fixed speed equivalents. “The PMmotor enables a VSD+ compressor to be used at up to 100% of its rating without effi- ciency drop off,” Ackerman explains, adding that the GA VSD+ range with permanent magnet motors has been extended to include options of up to a 75 kW nearly twice the capacity of the previous largest (37 kW).

With the inclusion of VSD versions for its GA 200 and GA 250 models, Atlas Copco has now closed a gap in its oil-injected screw compressor range. “This is a game-changing innovation for general industry. The GA 7-75 VSD+ variable speed drive compressor range offers improved performance, silent op- eration (down to 62 dB) and a compact footprint, thanks to its vertical drive train design. “The patent-pending PM motor has been in-house designed and is directly coupled to Atlas Copco’s best-in-class screw element. This technology will set new standards in the industry for years to come,” Ackerman believes. Low-pressure solutions Also expanding is Atlas Copco’s low-pres- sure range. “Low pressure compressors are widely used for wastewater treat- ment; pneumatic conveying of powders such as cement or dry food powders; for iron smelting furnaces; and in the chemical industry for processes such as sulfation. Across our ranges, which include roots and screw type blowers; screw and centrifugal compressor op- tions; along with multistage centrifugal compressors, we have low-pressure solu- tions from 200 mbar to 4.0 bar delivering air flows from 20 to 55 000 m 3 /h,” Van Wyk notes. “In the past, we have been weak in this area. We had a screw (ZS) and a centrifugal (ZB) offering, but these had a maximum capacity of 160 kW. Our ZS offering now goes up to 355 kW, and these also now include VSD options,”

Atlas Copco’s GA VSD+ compressors have been com- pletely redesigned to make best possible use of patented permanent magnet (PM) motor and drive train technology.

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Mechanical Technology — July 2016