Atlas Copco oil-free, low-pressure blowers help Becker Underwood protect bio-cultivation process

Becker Underwood’s impressive bio-control product portfolio covers a range of applications within the commercial and domestic horticultural sectors and the company is widely recognised as a world-leading producer of nematodes. These are worm-like microscopic organisms that attack and control specific horticultural pests – such as insect grubs and slugs – then reproduce to affect later generations, thus continuing the protection cycle. Safe for users, consumers and the environment, nematode products are applied to crops by water dispersible spray or drench formulations.

According to John Godliman, Becker Underwood’s Littlehampton site production manager, the plant’s original installation − a conventional direct-driven lobe type blower supplying process air to the fermenters in which the nematodes are cultivated − was exhibiting significant oil carry-over and reliability problems, a situation that impacted on the health of the bio-organisms and was contributing to excessive process costs.

As John explains: “The bio-cultivation process is reliant upon a continuous supply of oil free, filtered and sterile air to aerate the contents of three 25,000 litre fermenters. In the past, oil carry-over would block the filters and restrict the airflow. If the air supply is interrupted for any reason, an entire batch of nematode organisms can perish within a few hours. As a result of these critical issues, we were looking for a solution that would deliver a reliable, high quality, low-pressure, oil-free compressed air supply and, at the same time, help us to reduce process energy costs. We also required a supplier capable of providing complete product support”.

The answer to this essential requirement was met by an installation from Atlas Copco Compressors, comprising a fully integrated, oil-free, rotary screw displacement blower with variable speed drive and separate TD 650 aftercooler to reduce the temperature of the air before entering the fermenters.

The ZS unit was supplied by Atlas Copco Compressors housed in an ISO container to allow the unit to be installed outside and be located adjacent to the process area. The Atlas Copco ZS 45+ VSD-1200 blower is a fully integrated package comprising an integral main motor inverter, control and blower conditioning monitoring system.

With 60 years of experience Atlas Copco screw blowers use the internal compression principle using totally oil free screw compression elements. Atlas Copco screw technology requires no lubrication within the compression space, and with the special seals setup no rotor bearing oil can enter the compression chamber. This ensures the compressed air quality is totally oil free and meets the requirements of ISO8573-1 Class Zero certification for air quality.

Intake air is compressed between the rotors and their housing and oil-free, pulsation-free air at a pressures of 300 mbar to 1200 mbar is delivered at an output rate of between 259 -1145 m3/h, dependent upon the process demand.

This advanced screw technology has guaranteed 100% oil-free air for Becker Underwood’s critical process operations. Added reassurance was provided through the knowledge that Atlas Copco is the world’s first compressor manufacturer to receive the ISO8573-1 Class 0 certification for air purity.

As an additional benefit, the blower’s integrated frequency converter varies the motor speed to match changes in compressed air demand. This ensures only the minimum amount of energy is consumed, a feature capable of saving up to 35% in energy costs.

The ZS+ range of screw blowers are supplied complete with an Elektronikon operating system to provide control, to monitor overall system performance status, and to increase the blowers’ efficiency and reliability.

The Atlas Copco installation has met all of Becker Underwood’s replacement equipment criteria: a blower that supplies totally oil-free compressed air, reduces energy costs, and came from a supplier providing a complete product support service. What’s more, there is little doubt of John Godliman’s satisfaction with the blower’s performance, as he is more than happy to confirm: “Actions speak louder than words, and we have now ordered a second unit together with a centralised control system”.