你可能感興趣的試題

Some vessels are equipped with a water lubricated stern robeWhen at sea, operating under normal conditions, the water service valve from the ships saltwater system to the bearing should be （）.

A.closed, and no leakage permitted across the shaft packing
B.closed, and only slight leakage permitted across the shaft packing
C.open, and no leakage permitted across the shaft packing
D.open, and only slight leakage permitted across the shaft packing

單項(xiàng)選擇題

Sub-cooling is a method of reducing the temperature of the liquid refrigerant below its （）.

A.freezing point
B.floc point
C.condensing temperature
D.compression temperature