The expansion valve used in a refrigeration system regulates the
A. superheat of the gas leaving the compressor
B. back pressure in the evaporator
C. temperature in the refrigerated space
D. degree of superheat of the gas leaving the evaporator
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Which statement is NOT true？
A. In a simple vane pump, the rotor and cam ring are exactly concentric
Balanced vane pump has an elliptical cam ring
C. Liquid in both gear pump and vane pump are forced out to the outlet.
D. Balanced vane pumps can work at a higher pressure than the simple vane pump
The bridge should inform the engine room______before passing through congested or shallow
A. 24 hours
B. 2 hours
C. 1 hour
D. 15 minutes
Before "stand by" is rung on the engine telegraph, it is usual to give the main diesel engine a brief trial ahead and astern.
A. with power
B. on power
C. with air
D. on air
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