单项选择题

A vacuum is initially established in the first and second stages of a low pressure evaporator by the use of （）

A.vacuum drag from the auxiliary condensate system
B.individual vacuum pumps
C.a single non-condensing air ejector
D.a two stage air ejector

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单项选择题

The heated feed-water entering any flash chamber of a flash-type evaporator will（）

A.vaporize, with the un-flashed water remaining at the temperature at which it entered the flash chamber
B.vaporize, with the un-flashed eater equalizing to the saturation conditions existing in the f lash chamber
C.vaporize, with the remaining water a t a temperature greater than it entered the flash chamber
D.boil, allowing steam bubbles to rise through the brine at the bottom of the flash chamber

单项选择题

On a multistage flash-type evaporator, the flash chamber is （）

A.combined as part of the salt water feed heater
B.the open area above the brine levels in the first and second stages
C.combined as part of the distillate cooler
D.another term used to describe the vapor feed heater

单项选择题

Early models of the flash-type evaporators used a separate shell-and-tube heat exchanger as the air ejector condenser.More recent models use a combined air ejector condenser with the（）

A.distilling condenser
B.salt water feed heater
C.distillate cooler
D.flash chamber