The compressor suction line conveys the refrigerant vapor from （） to （）.

A . unload valve B . cooling water C . oil cup D . sum

A . raised B . risen C . reduced D . maintained constant

A、the low inertia B、the high inertia C、the low velocity D、the high velocity

A . centrifugal pumps B . jet pumps C . propeller pumps D . reciprocating pum

A . single B . Ⅱ C . Ⅲ D . multiple

A . injector B . compressor C . diffuser D . sipho

A . one B . two C . three D . four

A . to inject cleaning additives when the bilges are extremely dirty B . when the main condenser becomes fouled, in order to provide additional cooling water circulation C . to connect the rose box to the independent bilge suction D . if the bilges become flooded and they can not be emptied by any other mea

A、injection valve B、relief valve C、discharge valve D、inlet filter

A . be less than B . be larger than C . be as large as D . not be so large a

A、one valve seats upwards, while the other seats downwards B、the reed valves used on the discharge are made substantially thicker and heavier than thesuction valves C、the suction valve springs exert a greater tension than the discharge valve springs D、the discharge valve springs exert a greater tension than the suction valve springs

A . insufficient lubrication B . insufficient refrigerant C . excess refrigerant D . excessive opening of the expansion valve

A . one size smaller than the pump suction nozzle B . the same size as the pump suction nozzle C . one size larger than the pump suction nozzle D . installed with a short radius elbow at the pum

A . Increased suction head pressure B . Decreased feedwater temperature C . Pump recirculating line being open too much D . Excessive feedwater temperature

A . flooding back B . superheating C . overflowing D . recycling

A . increase compressor discharge pressure on demand B . increase compressor operating speed as necessary C . allow the motor to turn the compressor opposed only by friction D . reduce the compressor frictional load when starting

A . refrigerant overcharge B . overfeeding by the expansion valve C . a restricted suction strainer D . due to short cycling of the compressor

A . proceeding B . overloading C . collision D . flooding

A . vary their speed according to temperature and load B . start and come up to speed before air compression begins C . change speed according to overload demands D . reduce compressed air charge density

A . inwards B . outwards C . downwards D . upward

A . centerline of the pump and the level of the liquid in the suction well when the source of liquid is below the pump B . centerline of the pump and the suction liquid level when the source of liquid is above the pump C . centerline of the pump and the level of the discharge liquid D . liquid levels of the suction and discharge

A . a filter B . a strainer C . a magnetic filter D . a fine strainer

A . increase the amount of cooling water to the condenser B . decrease the amount of cooling water to the condenser C . add more refrigerant to the system D . remove some of the refrigerant from the system

A . by an fuel valve B . through an inlet valve C . with an exhaust valve D . from an outlet valve