A New Type Dual Temperature Box
A dual temperature box is researched. The dual temperature box adopts cascade refrigeration system. R22 is the refrigerant in the high temperature circle system, and R13 is the refrigerant in the low temperature circle system. The R22 system can operate both alone and with the R13 system. So the dual temperature box can achieve two vapor temperatures of -65 ¿Z and -20 ¿Z. And the refrigerant system of it can operate stable while the temperature is -65 ¿Z.