更多"The safety valves are mounted in pa"的相关试题:
[单项选择]The safety valves should be tested and adjusted when the boiler survey is （）
A. completed
B. carried out
C. cleaned
D. steamed
[单项选择]Safety valves on a boiler vent to the （）.
A. fuel tank
B. bilge
C. atmosphere
D. auxiliary exhaust line
[单项选择]Some cranes are mounted in pairs on a common platform which can be rotated through（）.
A. 360°
B. 270°
C. 180°
D. 90°
[单项选择]（） are mounted in pairs to protect the boiler against overpressure.
A. Safety valves
B. Water tubes
C. Steam stop valves
D. Blow down valves
[单项选择]The purpose of the safety relief valves installed on an auxiliary boiler is to （）.
A. relieve excess fuel oil pressure during the “off” fire cycle
B. admit water to the dry pipe
C. throttle the forced draft fan output for proper combustion
D. reduce excess steam pressure in the boiler
[单项选择]In comparison to exhaust valves, intake valves of diesel engines may be fabricated from low alloy steels because （）.
A. the beveled edges of the intake valves provide for serf-centering during seating
B. intake valves utilize stellite-coated valve seat inserts which reduce wear
C. the volume of air passing through intake valves is less than the volume of air passing through exhaust valves
D. intake valves are less affected to the corrosive action of exhaust gases
[单项选择]Temperature control valves installed in the jacket cooling water system of a diesel engine modulates the rate of water flow through the （）.
A. cooling water pump
B. nozzle cooling passages
C. cylinder jackets
D. heat exchanger
[单项选择]Thermostatic steam pressure reducing valves are used in the fuel oil service system to control the（）
A. double bottom fuel oil tank temperature
B. heater supply steam flow
C. pressure of the fuel supplied to the burners
D. attemperator steam flow in the heater discharge circuit
[单项选择]Thermostatic expansion valves can be adjusted for （）.
A. suction pressure only
B. head pressure only
C. superheat only
D. suction pressure and box temperature
[单项选择]Differential needle valves used in fuel injectors are directly closed by（）
A. cam action
B. spring force
C. fuel oil pressure
D. firing pressure
[单项选择]Bad valves operation of the reciprocating air compressors can be detected by observation of （）.
A. the discharge temperature low
B. the discharge temperature high
C. the discharge pressure rise
D. the inter-stage pressure low
[单项选择]Which of the listed pressure control valves would be used to establish the maximum operating pressure of a hydraulic system?（）
A. Pressure-reducing valve
B. Unloading valve
C. Counterbalance valve
D. Pressure-relief valve
[单项选择]If the discharge valves on a refrigeration compressor are leaking badly, the compressor should （）.
A. run continuously
B. not start
C. have high discharge pressure
D. short cycle on the high pressure switch
[单项选择]Under tropical conditions, control valves have fully opened, but the room still hot.What measures can be taken in such a case?（）
A. Keep the plant running all time
B. Start another blower
C. Increase the ratio of circulated to fresh air
D. Reduce the seawater flow to the condenser
[单项选择]Many diesel engine exhaust valves are being constructed with hollow stems filled with sodium in order to （）
A. provide added wear protection against today’s corrosive quality of fuel
B. increase overall valve strength due to the high gas pressures
C. assist in dissipating heat due to the extreme operating temperatures
D. reduce the overall weight of the valve thus helping eliminate valve spring surge and hammering
[单项选择]Bottom blow valves are installed on auxiliary water-tube boilers to （）
A. completely drain the boiler in an emergency
B. prevent sludge from forming in the drum
C. remove floating impurities from the boiler water surface
D. remove settled solids from the water drum
