The Quality Group have moved from inner city Rhodes to the new industrial hub of Huntingwood in Sydney’s West and contracted Donaldson Australasia to design and engineer a paper waste collection and handling system for their 24/7 operation.
The Quality Group requested Donaldson Australasia to provide a ‘workable solution’ for their waste handling system at Rhodes. The waste handling system at Rhodes was handling 9.5 tonnes of waste every 24 hours compared to the 14 tonnes now being collected and processed at Huntingwood. It took about four and a half months to design and install the new system.
For the new Huntingwood site, Donaldson Australasia were entrusted to improve on waste management system, improve the compactor area due to health and safety concerns, and improve on preventive maintenance, e.g. labour cost in housekeeping.
Paper trimmings at Huntingwood are collected from various high-rate work points including three saddle stitchers, one folder, a guillotine, one rotary trimmers, a perforation pick up point from two web presses and one perfect binder. All these machines are connected to a trim-handling fan through a common ductwork through which product is transported to a separator where strip is separated and returned through a chute into a compactor. Air and dust is then transported through a dust collector where the dust is separated from the airstream and an air emission of <15mg/m³ can be expected.
A rotary valve is fitted at the base of the separator hopper to prevent any air pressure into the compactor – a major source of pollution (paper trim and dust flying) when changing over bin. Dust in the dust collector is either collected into a bulky bag or a briquette press.
The main system comprises a separator and rotary valve are mounted onto a steel platform above the compactors. A pneumatically operated diverter valve and trouser legs allows diversion of product from one compactor to the next one. A main trim handling fan is at ground level between the building and first compactor. Dust collector and clean air fan are located near the compactors, along the building.
An important aspect of the design of this waste handling system was to make sure that conservative materials handling principles were followed to ensure the following problems do not occur:
- Material fallout – thus leading to duct blockage.
- Insufficient capture velocity.
- Discharge system does not choke, due to positive pressure in the compactor.
The installation is designed to operate 24 hours per day. Equipment is sized for heavy-duty operation.
The waste handling system uses waste capture hoods, and captured waste is conveyed through an aerodynamically balanced piping network made of galvanised steel. The purpose of this network is to convey the waste from the machines through the trim fan where the designated material is then separated from the airstream through the separator. Remaining material is then conveyed to the dust collector where final removal of the particulate from the airstream takes place.
A trim handling fan takes charge of the air capacity and the necessary pressure to transport waste reliably from the various inlets to the separator. A recovery fan extracts dust and air from the separator through the pollution control system. All the fans are mounted with flexible connection to the fan inlet and outlet to minimise vibration through the system.
One AMSP 35 Air Material Separator is installed on a steel platform above the compactor. A rotary valve fitted at the base of the separator hopper keeps the compactor airtight. The main duct from the trim fan is connected to the separator through a transition piece, which allows a suitable air velocity at the entrance of the separator.
After the separator, a DCE Dalamatic DLM 3/6/15 dust collector uses a reverse pulse jet to clean a fabric filter with a total filter area of 270m². This dust collector is also equipped with side explosion and full antistatic provisions.
Donaldson Australasia installed a briquette press to compact dust into a solid brick-like form. Dust collected in the hopper is discharged into a briquette press. In the event of a break down on the briquette press, it is possible to pneumatically divert the dust to a 1m³ bulky bag. The discharge equipment has been selected and sized to minimise risk of blockages and maintenance.
A rotary valve fitted at the base of the dust collector hopper seals the dust collector from outside. A dust level detector is fitted into the hopper to warn operators of any problems.
For system control, a monitor on the main control panel watches the current; if the current increases, it identifies that the main rotary valve underneath the separator may be suffering some level of blockage. A high level detector is fitted onto the dust collector hopper, which informs of a ‘dustbin full’ condition.
VSD (variable speed drive) drives the main trim fan, which allows the user to change the speed of the fan. This gives full selectivity of system performance and allows fine tuning the complete system for performance and energy saving.
Two level detectors are connected to an audible/visual alarm. All the necessary circuit breakers, contactors, indicator light and others components are fitted in a control panel located next to the main trim fan.
The trim handling fan is enclosed into an acoustic enclosure and fitted with inlet and outlet silencers. The dust collector fan is fitted with an outlet silencer.