We were called to their facility in the West Midlands to help improve the output quality of the recycled glass is typically broken into small fractions around 5-25mm in size. The recycler had previously attempted to work with alternative companies to develop this technology however they had failed to meet the design criteria and were considerably more expensive than the system offered by Impact.
Our brief was to come up with a robust and cost effective method of removing the light unpickable pieces of paper and other fibrous fines from the glass material stream. The commingled waste material is processed by a variety of equipment and finally enters a Trommel where the broken glass and paper of 5-25mm fraction size discharges at a rate of around 12 to 15 tonnes per hour. The Trommel separates a commingled material stream into different sizes via a large diameter rotating drum.
A successful system would mean the recycler could sell a contaminant free glass product adding significant financial benefit to their bottom line and making one of the only companies in the UK that can also process glass within their incoming material stream.
Impact came up with a simply yet high effective system which we installed at the end of the 5-25mm fraction discharge conveyor from the Trommel. A specially adapted drop chute / suction chamber was installed which the mixed glass and paper material has to enter. The difference in material density would mean that the lighter paper material would be drawn upwards in an adjustable conveying air volume and the heavier glass material would fall under the action of gravity from the base of the drop chute into a storage bunker below.
The suction chamber includes a number of special features to ensure accurate separation and ensure good durability. The waste material (mainly paper based material and other light fines) is sucked away from the top of the chamber in a range of ductwork where it is then separated from the air stream via a high efficiency cyclone assembly. Any remaining carry over dust from the system is then finally cleaned by a fully automatic reverse jet filter system, leaving the exhaust air cleaned to well below 10mg per cubic meters of air.
To ensure the system was energy efficient, the main fan utilizes a backward curve impeller design and is installed on the clean side of the filter assembly. This ensures that the fan is highly efficient, thus reducing the amount of motor power required for operation (approximately 85-90% versus typical material or dust handling fan design of around 52-60% efficient). The fan is controlled by a frequency inverter which is also the most efficient method of starting and controlling a motor.
Since its successful installation just under 3 months ago, the system has been in operation around the clock and has paid for itself many times over.
The engineering manager for the recycler commented 'I have been extremely impressed with the whole approach offered by Impact Air Systems. Their willingness to evolve new technologies to support the recycling industry has helped our company improve its operating margin in an extremely turbulent market. The quality of the finished equipment and trouble free installation process will definitely ensure they are involved in any subsequent projects within the group.'