【正文】 (3) too warm cooling water. A. (1) only B. any of (1), (2) and (3) C. either (1) or (3) D. either (1) or (2) Jimei University 1483 If a refrigeration pressor is running continuously without lowering temperature as normal in the refrigerator, the trouble may be_____. A. excessive condenser cooling water B. warm food in the refrigerator C. a shortage of refrigerant D. s shortage of pressor oil *1484 The color of the flame on a halide torch without any refrigerant present is____. A. blue B. green C. orange D. purple Jimei University 1485 The pressor suction line conveys the refrigerant vapor from_____. A. condenser to evaporator B. evaporator to pressor C. pressor to condenser D. None of the above. 1486 If an anchor windlass has been idle for some time, you should_____. A. repack all valve stems閥桿 B. lubricate it prior to use C. replace the foundation bolts D. balance the warping heads Jimei University *1487 Water allowed to accumulate in the hydraulic system oil will cause an oxidation process producing by products which are normally_____. A. gums, acids, and varnishes膠質(zhì) ， 酸性物質(zhì) ， 殘?zhí)?） B. removed by cellulose（ 纖維素 ） type filters C. neutralized by oil additives D. not removed by absorbent filters吸收性濾器 Jimei University 1488 It is possible to mount a double suction centrifugal pump impeller with the vanes facing in the wrong direction. This would cause the pump_____. A. head capacity to improve B. discharge to be reversed C. efficiency to decrease D. slippage to decrease Jimei University *1489 A thermostatic expansion valve is properly controlling evaporator superheat. Adjusting this valve to lower the superheat will result in a/an_____. A. evaporator pressure decrease B. evaporator coil overfeed C. evaporator capacity increase D. expansion valve diaphragm rupture Jimei University 1490 Air pressor receivers should be blown down at least_____. A. yearly B. quarterly季度 C. monthly D. daily 1491 Hydraulic machinery failures are monly caused by misalignment of the system ponents and by_____. A. hydraulic fluid contamination B. excessive fluid friction C. turbulent fluid flow湍流 D. fluid pressure surges沖擊 Jimei University *1492 A double suction centrifugal pump impeller has been installed in the reverse direction, and will_____. A. have a greater head capacity B. operate with increased impeller efficiency C. discharge through the suction side of the pump casing D. require more power to run the shaft Jimei University *1493 If a centrifugal pump were continually operated with the discharge valve closed, the _____. A. motor controller overload would open B. pump would eventually overheat C. relief valve would continuously cycle open D. motor would overheat（ 功率隨著流量的增加而增加 ） Jimei University *1494 When you adjust a thermostatic expansion valve, _____. A. refrigerant must be bled off the sensing line before adjustments are made B. all refrigerant must be pumped into the receiver before adjustments are made C. time must be allowed for conditions to stabilize in the evaporator before further adjustments are made D. all refrigerant must be routed through the dehydrator干燥器 while changing the superheat setting Jimei University 1495 Hydraulic machinery failures are monly caused by contamination of the hydraulic fluid and_____. A. fluid friction B. fluid turbulence C. ponent misalignment D. pressure surges Jimei University *1496 The refrigeration system low pressure cutout switch is actuated by_____. A. an electric system manager B. a sensing bulb at the tail coil of the evaporator C. pressure changes in the suction line D. failure of the king solenoid valve主電磁閥 Jimei University *1497 A knocking sound emitted from an unloaded air pressor is probably caused by _____. A. damaged intake valves B. excessively tight mounting bolts C. insufficient cylinder lubrication D. a loose piston Jimei University *1498 Which of the following statements is true concerning any evaporator? A. High conductivity of the distillate indicates distillate salinity is excessive. B. Increasing the absolute pressure of the shell will increase the distiller39。 (3) the external surface of the housing. A. (1) only B. (2) only C. (1) and (2) D. (1), (2) and (3) Jimei University 1481 Thermostatic expansion valve are____. A. either all the way open or all the way closed B. normally open C. throttled depending on load D. controlled by suction pressure 1482 Which of the following may cause that excessively warm water leaves the condenser in a refrigeration plant? (1) too little cooling water。 (2) increase feed pump pressure. A. (1) B. (1) and (2) C. (2) D. neither (1) nor (2) 1463 Foaming in the steam drum may be caused by_____ in a boiler. A. oxygen in the water B. poor boiler design C. density too high D. excessive steam demand Jimei University 1464 The water in an auxiliary boiler should be tested daily for_____. A. dissolved oxygen B. chlorides C. sludge D. dissolved nitrogen 1465 In a_____ boiler the hot gases from the furnace pass through the tubes while the water is on the outside. A. watertube B. firetube C. exhaust gas D. None of the above. Jimei University 1466 _____ should be tested and adjusted when the boiler survey is carried out. A. The boiler oil tank