单项选择题
A.the distillate produced has greater purity
B.no boiling occurs on heat transfer surfaces
C.evaporation occurs at a higher rate
D.the incoming feed is at a higher temperature
单项选择题 A liquid sight flow indicator in a refrigeration system is examined and gas bubbles are noted in motion with the fluid flowThis means （）.
单项选择题 Which of the filter/strainer units listed permits you to clean the element while leaving the system on the line?（）
单项选择题 A sight glass is installed in the liquid line to indicate the condition of the refrigerant charge and may also indicate the （）.