The Delta Hybrid rotary lobe compressor, manufactured by Germany-based gas conveying and compression company Aerzen, produces negative pressure and positive pressure from –700 mbar to 1 500 mbar, reports Aerzen sub-Saharan Africa subsidiary Airgas Compressors.
The patented compressor offers the combined features of a positive displacement blower and a screw compressor in one unit. It was launched locally by Airgas in 2009, with intake volume flows ranging from 110 m3/h to 9 000 m3/h.
Airgas marketing coordinator Andreas Stubel notes that, by combining the advantages of a positive displacement blower and a screw compressor, the Delta Hybrid serves as a cost-effective, yet highly-reliable, air conveying solution for applications, such as cement production, food mills and water treatment, which often require more than 1 bar of operational pressure.
Pressure ranges for blowers go up to 1 bar, but to reach higher pressures, a capital-intensive compressor is usually required.
“The Delta Hybrid serves as the ideal ‘in-between’ solution for these types of applications, as it is less costly than a compressor and provides higher discharge pressures than a blower,” he explains.
According to Stubel, energy consumption constitutes 90% of the total life cycle costs of compressed air conveying machinery. With rising energy costs, coupled with uncertainty of supply, the Delta Hybrid’s energy efficiency is another major benefit for the South African industrial market.
“The Delta Hybrid was developed with a focus on increasing energy efficiency and achieving a significant reduction in energy costs and greenhouse gas emissions. Combining the efficiencies of rotary lobe blower and screw compressor technologies reduces the energy consumption under ideal conditions by up to 15%, when compared to standard compressors,” he says.
For greater energy efficiency, the Delta Hybrid is also available with a variable-speed drive option, which ensures more control of the air volume intake and torque values produced by the machine during operation.
The Delta Hybrid also features a number of additional developments, including an enhanced fluid design of the inlet and discharge ports for ideal flow conditions, and a patented bearing system that results in a bearing life span of over 60 000 operating hours, at a differential pressure of 1 000 mbar.
A discharge silencer, without absorption material, is provided to help avoid contamination of the air system and makes the Delta Hybrid ideal for use in pneumatic conveying systems in the food industry. “It also avoids any accumulation of broken-down absorption material in the fine diffuser systems of wastewater treatment plants. It prevents clogging, while reducing maintenance costs too,” adds Stubel.
Additional insulation and a specialised inlet cone reduce pressure losses and noise, as does an acoustic enclosure. “This ensures a quieter working environment, which, in turn, results in less hearing protection being required. Further, it allows for more effective communication between workshop employees,” he says.
The Delta Hybrid has been particularly well received by the South African cement industry, Stubel notes.
“In the cement manufacturing process, limestone and marl are crushed, dried and ground to a fine meal before being stored in silos. The raw meal is then forwarded into the rotary kiln by compressed air,” he explains.
With the silos and rotary kilns sometimes being located far apart from each other, the pneumatic pipelines are long and require higher pressures that positive displacement blowers are unable to provide. “This is where the Delta Hybrid adds considerable value, as it provides the higher pressure at reduced overhead and energy costs, when compared to a positive displacement blower,” says Stubel.
Stubel is optimistic this innovative solution will increase market share in local industries and across national borders. “As energy costs continue to rise at an exponential rate, industries continue to place a stronger emphasis on energy efficiency without having to increase expenditure.
“As a result, I believe that we can strengthen our existing long-term ties in the water treatment, chemical, milling and general pneumatic conveying industries through our many years of experience,” he concludes.