Dry coal-fired pure air hot air furnace in Pakistan's gypsum industry. The LRF series hot blast stove is a new generation of heating products. The product adopts multi-head spiral groove heat exchange technology and integrates combustion and heat exchange design, which makes the product compact, reasonable layout, high heat exchange intensity, fast heating, and high thermal efficiency . It has the characteristics of small floor space, convenient installation and operation, clean hot air and stable performance. The hot blast stove uses indirect heat transfer technology and uses clean air as the heat transfer medium to provide an ideal direct heat source for the heating process of various industries. The heating temperature is divided into low temperature (80~150℃) and medium temperature (200~300 ℃), high temperature (400~550℃), three grades, customers can freely choose according to the requirements of the drying process. This product is widely used in the drying, spraying and dehydration of various materials such as chemicals, food, medicinal materials, tobacco, ceramics, and building materials. It can also be used for heating in buildings such as factory buildings, auditoriums, farm sheds, and livestock houses, as well as dehumidification or heating processes in underground mining areas and underground projects.