Compressed air system built for energy savings

Australian carpet manufacturer Godfrey Hirst has optimised its Geelong production facility with an environment-friendly manufacturing solution, founded on a purpose-built compressed-air system from Champion Compressors.

Construction of carpet pile takes place in the tufting machines - these are not unlike large multi-needle sewing machines - where the yarn is stitched into a primary backing. Patterns and colours can be applied to the carpet either by tufting with coloured yarns, or by the subsequent dyeing or printing of the completed pile. A second robust woven fabric is then fixed to the back of the pile, providing further firmness and stability. At this point, the pile is ready to be finished with the application of a stain-resistant treatment to provide long-term protection.

If a change of yarn colour is necessary during a production run, the original yarn needs to be cut and joined to a yarn of a new colour - this is achieved with the aid of compressed air. A blast of compressed air from a ‘splicing’ device entangles the cut fibres of both yarns, forming an effective join. Compressed air is then used to blow the new yarn through a tube into the needle assembly of the tufting machine so the tufting process can recommence.

With 30 tufting machines handling up to 1200 separate yarns each, this step of the carpet construction is a major consumer of compressed air. So, when Godfrey Hirst embarked on an expansion of its production facilities, the company contacted Champion Compressors to design, install and commission a fully engineered compressed-air system.

The Champion solution comprises two skid-mounted 132 kW VOC 132 rotary screw compressors, equipped with a variable output airend. These units are built to meet a system demand of 1300 cfm at 12 psig and are complemented with a suite of Champion’s ancillary air-treatment equipment. Included is a comprehensive air dryer and filtering system, designed to integrate with the on-site air receiver and an existing 75 kW CSD75 Champion compressor. “High quality air is essential to our process,” says Godfrey Hirst reliability engineer, Terry Malloch. “Clean dry air avoids staining of the yarn, which would compromise the final product.”

Incorporated into the customised compressed-air system design are two purpose-built heat exchangers (one per compressor). The benefits of this design are two-fold - waste heat in the compressor lubricant is captured and used to pre-heat make-up water for the factory’s boiler, while at the same time alleviating the load on the compressor’s integrated fan-driven cooling system.

“Day-to-day operation is also more efficient, as the new compressed-air system is fitted with an automatic lead/lag controller, enabling the selection of one ‘operating’ and one ‘standby’ compressor. The compressor controller also allows connectivity to the plant-wide supervisory control and data acquisition (SCADA) system,” says Mark James, Champion Compressor sales manager.

Between 80 and 90% of the electrical energy consumed by air compressors is converted to heat. With this in mind, Champion engineered the heat-recovery system to capture the waste heat and utilise the energy for raising the temperature of the boiler make-up water. Champion designed the system to deliver a 300 °C temperature rise to 4500 L/min of make-up water. The consequent reduction in boiler heating costs is a direct energy saving.