hot blast
/ˌhɒt ˈblɑːst/ /ˌhɒt ˈblast/noun
The practice of preheating the air forced into a blast furnace in order to improve the efficiency of working of the furnace; the blast of hot air so used.
- The practice was patented and promoted by J. B. Neilson from 1828 onwards (British Patent 5701)..
Origin
Mid 19th century. From hot + blast.