Bungalow & Villa (B&V) is one of New Zealand’s leading manufacturers and suppliers of renovation products. B&V carry and stock a large selection of timber mouldings, wood turning products, fretwork, doors and architectural hardware. These products are manufactured in-house in the B&V Avondale factory – Auckland NZ.
Bungalow & Villa’s manufacturing process generates a high volume of timber waste and shavings. High speed moulding requires very effective dust extraction to avoid product imperfections.
In 2012 Airtight Solutions was commissioned to redesign a reliable, high performing and fully automated dust extraction and materials handling solution.
Airtight Solutions designed, engineered and manufactured a fully automated collection, filtering and briquetting system, designed to remove wood waste from the factory and convert it into compacted briquettes, reducing the waste volume by 90 percent.
The Extraction System: – AIRTIGHT NFS2HJ 45kW
The system uses a main extraction fan to provide airflow at the woodworking machine usage points. The pickup points are able to be isolated with slide dampers to ensure consistent airflow is available at the required pickups, to allow maintenance and reduce power requirements.
The ducting system is made up of the Airtight Solutions quick fit (QF) ducting throughout.
The main 45kW 4 pole extraction fan has a variable speed drive (VSD) set to 1450 rpm. The main fan draws the shavings into the silo to drop out the heavy/large waste. The light waste will be carried out to the fan and into the 2HJ filter. The filter then discharges the dust through a rotary valve in to the *waste bin.
*Note: the bin has been removed in this instance and a separate vacuum line connected back to the silo. This eliminates the need to empty the bin.
The filter bags in the filter are automatically cleaned by reverse air regeneration fans that operate periodically. The cleaning interval can be adjusted via a selector switch in the filter control panel.
Upon shut down (ie stop button pressed), a cleanup cycle is initiated to ensure the filter bags are clean when the system next starts up.
Dust from 2HJ Filter
The dust is discharged from the rotary valve into the empty pipe. The dust is extracted from this empty pipe through a duct to the silo, using the vacuum from the main extraction fan. This negates the need for a waste bin under the rotary valve.
A back pressure flap is fitted to the inlet of the empty pipe, to prevent dust emissions from here during the filter regeneration fan clean down, when the filter system is turned off.
A removable cone & insert in the empty pipe regulates the flow of air/dust and provides an air passage to prevent blockages.
The system has a silo shaving storage and feed system (live floor bin).
The shavings are pushed out, operated by a hydraulic power pack, to the end of the silo into an auger that feeds the shavings into a rotary valve. The rotary valve then feeds the shavings into the hopper of the Airtight AP775 Briquetting Press.
The cylinders have proximity switches, high and low level switches to ensure correct operation and alerts operator when certain filling levels are achieved.
Sight glasses were installed into the Silo for easy visual assessment of dust levels.
The system has an Ap775 Briquetting Press system that compacts the shavings by 90%. The waste is pressed into briquettes of approx. 70mm diameter x 70mm long, at a rate of approximately 1 per 7 seconds (approx. 120 kg/h).
The shavings are fed into the briquetter hopper. The hopper has an agitator in the bottom and an outfeed screw into the briquette press chamber. The briquette pressing is achieved with a hydraulic power pack.
Integrated system automation:
The hopper has a high level switch to ensure the hopper is not overfilled and to turn off the silo feed system when the product has reached that switch level (paddle type).
The hopper also has a low level switch to ensure the Briquetter is turned off when the hopper is near empty when the product has reached that level switch.