the discharge temperature low
the discharge temperature high
the discharge pressure rise
the inter-stage pressure low
第1题：
Compressed air is supplied by air compressors to______.
A.the air receivers
B.the starting valves
C.the cylinder covers
D.the distributors
第2题：
starting air bottles
diesel engines
boilers
refrigeration compressors
第3题：
If the engine does not start on air, it may be due to
A.low compression of the fuel pumps
B.incorrect timing of fuel pumps
C.the starting air valves stuck
D.air-locks in fuel oil pipeline
第4题：
Holding the valve open for a long period
Increasing the starting air pressure used
Opening the stating air valve quickly
Reducing the starting air valve size
第5题：
the cooling effect of the condensate reduces the compressors efficiency
a danger of explosion exists whenever water is present in a compressor
water causes erratic operation of pneumatic components
the volumetric capacity of the first stage is reduced if water remains
第6题：
What is the most probable cause of reduced capacity in a reciprocating air compressor ________．
A.Carbon on cylinder heads
B.Faulty unloader
C.Leaking air valves
D.Plugged air cooler
第7题：
rotary compressors
reciprocating compressors
centrifugal compressors
screw compressors
第8题：
第二组
Under normal operation, some lubrication oil mist may be discharged from the air compressor to the air start system. This oil may be from excess compressor cylinder lubrication, from faulty oil scraper rings, or may even be suspended oil vapor contaminating the engine room atmosphere and drawn in at the compressor suction. Oil discharge is kept to a minimum by draining the after cooler, air receiver and starting system. If small quantities of lubrication oil do get passed into the starting air system, they will deposit as thin moist film over internal pipe surfaces but are not readily combustible. If a cylinder non-return valve leak while the engine is in operation, some hot gas, possibly with unburned fuel and cylinder lubrication oil, may be blown through the valve to the adjacent air manifold. With further heating from the leaky valve, this, together with the already deposited oil film, will carbonize and form. incandescent carbon. If starting air is applied to the system while still hot, the high pressure air coming into contact with the burning carbon may cause an explosion. Such an explosion will cause a flame to pass back through the air start pipe system, evaporating the deposited oil film and igniting it in the presence of air. Very high velocities and shockwaves are generated which may rupture pipes and fittings.
Alternatively, if excessive oil has entered the air start system, a mixture of air and oil droplets may be discharged through the open cylinder non-return valve during starting. This spray may ignite due to high temperatures in the cylinder, causing a flame through the still open valve to the air manifold.
To prevent an explosion, air start valves must be correctly maintained and lubricated to ensure correct timing and free movement with positive closing. Oil in the system must be kept to a minimum, pipe lines must be drained and cleaned internally when necessary and oil discharge from air compressors must be kept to a minimum by good maintenance.
The passage is mainly about
A.crankcase explosion
B.scavenge box fire
C.starting air pipe
D.the danger of explosion in the starting air system
第9题：
starting air pressure too high
correct timing of starting air valves
three of the six starting valves stuck
the turning gear disengaged
第10题：
dust entering the high pressure stage
lube oil carbonization
discharge pulsations
inter-stage vapor lock