The invention relates to a direct-heat and constant-temperature circulating
heat pump drying machine. The direct-heat and constant-temperature circulating
heat pump drying machine comprises a
machine case, a draught fan arranged in the machine case, an
evaporator arranged on the right side of the draught fan, a condenser arranged on the right side of the
evaporator, a circulating loop connected with the
evaporator and the condenser, a throttling device, a
liquid storage tank, a compressor, an air inlet
pipe arranged on the throttling device, an electric adjusting valve arranged at the
tail end of the air inlet
pipe, an air supply
pipe arranged on the left side of the condenser, an air returning port formed in the
tail end of the air supply pipe, an air outlet formed in the right side of the condenser, and a
centrifugal fan arranged in the air outlet, wherein the throttling device, the
liquid storage tank and the compressor are arranged on the circulating loop. According to the direct-heat and constant-temperature circulating
heat pump drying machine, the
air volume can be adjusted through the electric adjusting valve and the
centrifugal fan, and the constant-temperature air discharging is achieved; a circulating air
flue is formed through the air outlet and the air returning port, exhausted
waste heat can be recycled, and the drying efficiency is high. Heat is absorbed through the evaporator, heating of the evaporator is improved, the effect of energy saving is achieved, the work efficiency ratio of a main machine is increased, meanwhile, the structure is simple, and using is convenient.