单项选择题
A.increases brine density
B.increases distillate salinity
C.reduces metal corrosion
D.reduces heat transfer
单项选择题 In order to properly remove air from the casing of a centrifugal pump when starting, the pump should have a （）.
单项选择题 The valve best suited for throttling gas or liquid flow in a pipeline is the（）.
单项选择题 Which of the listed statements is a characteristic of the liquid charged power element used with thermostatic expansion valves?（）