Over the years Thermax has developed many fabric filtration systems, achieving several significant breakthroughs and industrial application milestones. Some of the first few installations of Reverse Air Bag House were commissioned for carbon black, cement kiln and sponge iron de-dusting applications in India.

Other major applications handled, were for Ferro-alloys and other metallurgical processes and lime kilns. These systems have been designed to clean emissions from various industrial processes and handle a wide range of gas volumes – from 60,000 m3/hr to more than 10,80,000 m3/hr. Depending upon the duct characteristics, Thermax offers the most economical and efficient cleaning method to minimise pressure drop across the bag house.

The Reverse Air Bag House (RABH) is a custom-built filter, designed for cleaning gases with typically high flow rates and high temperatures.

The typical Thermax RABH is modular in construction, with four or more independent modules – the modules are set in pairs when the gas flows are on the higher side. The sealed air gap between the modules adds to the insulation to increase the operating economy. The extra space created by the hoppers provides a large passageway between rows down the middle of the system. This passageway is divided into three sections horizontally to make the inlet plenum, outlet plenum, and the reverse-air plenum.

This construction and operation of the units not only offer control on velocity profiles but also facilitates on-line maintenance. Each module can be isolated for inspection or maintenance by closing the inlet, outlet and reverse air damper, while other modules are in operation. The units – being custom built and voluminous – are dispatched knocked down to structural and panels.