BHEL, Tiruchi, achieved a major landmark during 2012-13 by fully establishing all manufacturing processes for supercritical range of boilers.
It has manufactured associated valves and piping products adaptable to the machine tools for handling larger sizes, intricate assemblies, and advanced materials, according to its annual report. By manufacturing 2.5 lakh valves, the Tiruchi unit has increased its volume of production by 18 per cent. Shop trial assemblies of hopper to furnace transition panels and hopper to spiral furnace wall panels were carried out for the first time.
Unique components such as connecting sphere, mixing sphere, intricate burner panels, headers of 2.7-metre height, and wind box of 16.7-metre height weighing 42 tonnes were successfully manufactured for the first time for supercritical boilers. A record number of 300 coal feeders and over 150 wind boxes were dispatched during the year. Other components manufactured for the first time include P92 headers of 660 mm X 120 mm outer diameter and up to 120 mm wall thickness, P91 headers of up to 813 mm diameter, economiser coils from 135-metre-long tubes built up using straight tube butt joints and forged high pressure valves of F91 material.
New manufacturing processes developed and established include fabrication of panels and coils using new materials. Design changes were made in coils for super critical boilers to eliminate the need for normalising and tempering after bending. Direct bending of ferritic steel tubes with close bend radius eliminated the need for hot squeezing, normalising, and tempering in furnace for T23 tubes.
The unit added a new facility for the manufacture of wall blowers. Innovative methods were adopted and modifications were made to tools and fixtures for cycle time reduction.
Innovations were also introduced to reduce site work and erection time.
A new rack-type soot-blower was manufactured and supplied to TNPL, Pugalur. The unit also established tube to tube-sheet weld joints with close pitch in titanium heat exchanger.