Dust Extraction Using
Reverse Pulse Filtration

The Challenge


The fabrication and installation of three large dust extraction systems for various applications within a large foundry.

The Delivery

Kooltron fabricated all three systems at our premises. They were then sand blasted, hot dipped galvanised (where applicable) and painted by a specialist outsourced party. The plants are almost identical with the exception of one system, which has two 1200mm diameter x 6200mm high cyclones fitted with dedicated disengaging hoppers, rotary valves and screw conveyors.

dust vacuum system ductingextraction equipment erecteddust catchment hopper

The Solution

  • The filtration is via a reverse pulse system where 612 fabric filters, each 145mm diameter by 3000mm in length, are housed in a bag house with special internal cages to ensure that the filters retain their shape. 68 Solenoid valves provide the necessary compressed air to clean the filters via blow pipes located above each filter.
  • The pulse duration and frequency of the pulse from each of the solenoid valves is controlled via a sequential timer, which also controls an additional cleaning cycle when the fan is switched off. The latter process allows a deep cleaning action to prolong the filter lifespan.
  • The bag house is manufactured from 4mm mild steel with external vertical and horizontal ribs. The clean chamber, dirty chamber and the hopper section comprise the bag house, which has a footprint of 6500mm x 3500mm and stands 13000mm tall. The filters are located in the divider plate that separates the clean and dirty chambers.
  • A screw conveyor is located below the bag house hopper to direct all the collected dust to a rotary valve, which dumps waste to a skip while the bag house is under negative pressure.
  • The welded and bolted steel support structure accommodates the bag house as well as the maintenance walkways that are located at four different levels. Cat ladders provide access to the individual walkways and all walkways and ladders are fitted with handrails, kickplates and safety cages respectively.
  • The fan is a 1250mm diameter SISW BCC that has a 350kW 380V 4-pole motor. The 1250mm diameter fan impeller has a 25mm thick back plate and is belt driven to provide the extraction rate of 45 000m³/hr against the system resistance of 7300 Pa.
  • Each system is fitted with an in-line damper that automatically adjusts the system pressure to compensate for clean or dirty filters.
hopper is lowered into positionhopper sections - 10 ton melting furnacehopper in place ready for final connectionsthe clean and dirty dust chambers are lowered into position

Safety benefit: The bag house has 6 blast dampers located in the dirty chamber that will prevent damage to the bag house in event of an explosion. There are also 6 manually operated dump gates in the hopper section that allow for an emergency dump of dust should the need arise.