The process during which liquid containing a reasonable amount of sensible heat at a particular pressure immediately changes into steam after admitted to a chamber at a lower pressure is called （）.

A.to cut down the amount of cooling water needed
B.to prevent an excess amount of cooling water from being discharged to the bilges
C.to supply hot water to the evaporator for more economical operation
D.None of the above is tree

A.to decrease scale formation
B.for better cooling effect
C.for more economical purpose
D.to raise vacuum

A.a brine pump
B.an air ejector
C.a feed water pump
D.a condensate pump