單項選擇題Sludge may form in the lubricating oil crankcase of a reciprocating air conditioning compressor as a result of （）.

A.wax precipitation in the lube oil
B.contamination by dust, scale, or moisture
C.refrigerant bubbles in the lube oil
D.refrigerant reducing the lube oil viscosity


您可能感興趣的試卷

你可能感興趣的試題

1.單項選擇題In a chilled water air conditioning unit using a reciprocating compressor, the refrigerating effect of the primary refrigerant can be increased by （）.

A.increasing refrigerant pressure in the coil
B.increasing chilled water flow through the cooler
C.sub-cooling the refrigerant in the condenser
D.superheating the refrigerant in the compressor

2.單項選擇題A re-heater in an air conditioning system functions to （）.

A.control inlet air temperature
B.control inlet air volume
C.maintain relative humidity at 15%
D.restore conditioned air temperature to a comfortable level

3.單項選擇題If one of the bilge system manifold valves does not properly seat, the （）

A.bilge well connected to that valve, plus the second bilge well being pumped will be completely emptied
B.bilge system will lose vacuum and prevent the other bilges from being pumped out
C.bilge well aft connected to that valve will siphon its contents to the forward bilge wells
D.discharge pressure will be too high

4.單項選擇題An exhaust gas bypass is installed on a waste heat boiler in order to （）.

A.bypass exhaust gas at high loads to prevent excessive back pressure
B.bypass a portion of the exhaust gas at peak loads for better efficiency
C.recycle exhaust gas to the turbocharger
D.minimize moisture condensation in the boiler gas passages at low loads

5.單項選擇題Which of the following actions should be taken if during a routine maintenance inspection of a centrifugal pump, localized scoring on a pump shaft sleeve is detected?（）

A.Correct the cause of the scoring and repair the sleeve or replace with a new one
B.Reassemble the unit and provide more water leak off for proper lubrication
C.Check for parallel alignment of the sleeve radial faces to the sleeve bores
D.Reassemble the unit and adjust the governor to obtain a slower speed