The equipment shell has a thermal insulation layer (rock wool thickness is 100mm), the door cover, feed port, etc. are sealed devices, there is no steam leakage phenomenon, low heat loss, and according to the best energy-saving way to consider, the user can recycle the condensate water, condensate water back to the boiler system (the condensate water is soft water, no testing, no pollution), so as to form the best heat cycle process. The heat energy loss of the tube bundle machine is reduced to the lowest point, so the tube dryer is one of the best energy-saving equipment in the drying industry.