单项选择题
A.one size smaller than the pump suction nozzle
B.the same size as the pump suction nozzle
C.one size larger than the pump suction nozzle
D.installed with a short radius elbow at the pump
单项选择题 In the operation of a flash type evaporator equipped with air ejectors,the air and non- condensable gases are evacuated directly from the （）.
单项选择题 The refrigeration compressor in a water cooled refrigeration system is short cycling on the high pressure cutout switch， One reason for this could be the （）.
单项选择题 Excessively low air pressure occurring in the intercooler of a reciprocating air compressor is caused by（）.