14/09/2021
Bell Less top charging system of Blast furnace...
The development of Bell less top charging system by S.A. Paul Wurth was a big quantum jump in technology and hence this system rapidly gained in popularity. The BLT charging system has the following advantages.
It allows nearly continuous charging of the BF. While the rotating chute is distributing the contents of one lock hopper bin, the other can be filled.
It solves the problem of gas sealing under a high pressure operation
It provides flexibility in the distribution of BF burden. It can carry out one ring charging, multi ring charging, spiral charging, sector charging and point charging both in manual and automatic mode. Charge regulating valve provides accurate and constant distribution of burden materials.
It provides improved BF operational stability and efficiency leading to better hot metal chemistry control.
It contributes to increase in the BF productivity.
It reduces BF coke rate and helps in achieving higher injection rates of pulverized coal.
It contributes to higher campaign life due to reduced BF wall heat loads.
It greatly reduces the maintenance time and frequency of maintenance of top equipment. The chute can be replaced within a short period of time.
The top equipment is of light and compact construction compared to other high pressure top charging system.
However the height of the BLT top equipment is more than the two bell type charging system. BLT charging system can be integrated with skip hoist or conveyor belt charging system. BLT charging system has the following main component parts.
A movable receiving hopper.
One or two material lock hoppers equipped with upper and lower seal valves and a material flow control gate.
A central vertical feeding spout
A rotating adjustable angle distribution chute
A rotational and tilting drive mechanism
Hydraulic, lubrication and cooling systems
Monitoring and control systems
