Mechanical Technology July 2015

⎪ Hydraulic and pneumatic systems ⎪

Rising electricity costs and unreliable supply from the national grid are prompting industrial operations to seek more energy-efficient equipment. However, the major challenge in South Africa still lies in the market’s reluctance to focus on long-term investment, by spending more on the initial purchase price to ensure future savings, according to Aerzen Airgas marketing co-ordinator Andreas Stubel (left). Compressor investments, long-term

“ A erzen Airgas offers highly- efficient equipment that can assist operations in considerably reducing energy bills,” begins Stubel, admitting, however, that the initial purchasing cost is a dominant factor in the decision mak- ing process. “This makes the introduction of more expensive but efficient equipment chal- lenging. Understandably, buying equip- ment at the lowest price makes financial sense, but the misconception lies in the fact that cost saving decisions are based primarily on short-term financial goals,” he says. Stubel points out that purchasing

standard or cheaper equipment does not save money, and may in fact cost more in energy consumption and maintenance in the long run. “Bearing this in mind, Aerzen Airgas offers the local market the Aerzen Delta Hybrid rotary lobe compres- sor, an oil-free air conveying alternative to standard roots blowers,” he continues. The Delta Hybrid is designed to be an optimised combination between a blower and screw compressor, and makes use of a patented twisted rotor profile. It is designed for a variety of applications where air and neutral gases must be conveyed oil-free. These include; waste- water treatment plants, the chemical industry, power plant technology and for

The Delta Hybrid is designed to be an optimised com- bination between a blower and screw compressor, and makes use of a patented twisted rotor profile. the pneumatic transport of powder and granulate goods. The Delta Hybrid is available in four models: L, S, H and E. The L model has been designed for pressure ranges of up to 800 mBar; the S model for 1 000 mBar and the H model for pressures of up to 1 500 mBar at sea level. The E model is a vacuum machine with a maximum negative pressure of -700 mBar. The Delta Hybrid is effectively an in-between solution, as it crosses the pressure range between roots blowers and low-pressure screw compressors. “The Delta Hybrid is a compres- sor designed from the bottom up with energy-efficiency in mind. As a result, it is up to 15% more energy-efficient when compared to standard positive displace- ment blowers. It has an optimised fluidic design of inlet and discharge ports to provide for ideal flow conditions and reduced slippage,” Stubel explains. The inlet air is sucked in on the cold side of the unit and a specially designed discharge silencer increases the compres- sion efficiency. What’s more, the belt- driven Delta Hybrid offers the significant advantage of exact sizing for customer requirements. For demonstration purposes, an Aerzen Delta Hybrid D 24 S was tested alongside a standard positive displace- ment blower, both fitted with 37 kW IE2 motors. Both machines were con- figured to produce a system pressure of 900 mBar and an intake volume flow of 1 000 m³/h at sea level. The Delta Hybrid consumed 27,5 kW to produce these figures, while the blower consumes 32,3 kW for the same performance. “On average, therefore, the Aerzen Delta Hybrid is 14% more efficient than the

In conjunction with new machine sales, Aerzen Airgas offers numerous after sales services including field service, repairs and overhauls to the entire range of Aerzen blowers and compressors.

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Mechanical Technology — July 2015