更多"The purpose of the purge valve at t"的相关试题:
[单项选择]The purpose of the programmed purge cycle on an automatically fired auxiliary boiler is to（）
A. cool the furnace to prevent pre-ignition
B. remove explosive vapors from the furnace
C. evaporate accumulated unburned fuel oil
D. provide sufficient air in the furnace to allow ignition of the fuel
[单项选择]What is the purpose of a relief valve?（）
A. to fill 2 tanks at the same time
B. to use pump at a higher pressure
C. to return liquid to suction side if discharge valve is closed
D. All of the above are true
[单项选择]The purpose of the delivery check valve used in a diesel fuel injection jerk pump is to （）.
A. assist in a quick cutoff of fuel injection
B. allow oil backflow from the injector to the helix
C. reduce fuel oil pressure between injection strokes
D. meter the quantity of fuel delivered
[单项选择]The purpose for the bag or box on top of some survival craft is to（）.
A. right the craft in case of capsizing
B. increase area for radar detection
C. act as a sail in case of a power loss
D. steady the craft in heavy seas
[单项选择]The diesel engine valve subjected to most severe conditions of service is the （）.
A. cylinder exhaust valve
B. air starting valve
C. air inlet valve
D. cylinder relief valve
[单项选择]For what purpose would using a Lambert conformal chart be more convenient than using a Mercator?（）
A. Plotting radio bearings over a long distance
B. Determining latitude and longitude of a fix
C. Measuring rhumb line distances
D. Measuring rhumb line directions
[单项选择]Increasing the valve clearance between a valve stem and rocker arm, will result in the valve （）
A. closing later
B. opening sooner
C. staying open for a shorter period of time
D. staying open for a longer period of time
[单项选择]The safety valve should be （） in the presence of C/E and Surveyor.
A. tightened up
B. sealed up
C. opened up
D. unscrewed
[单项选择]The needle valve in a fuel valve will （） when the fuel pressure action on the needle valve tapered face exerts a force lower than that of the spring compression.
A. be jammed
B. be opened
C. be seated
D. be broken
[单项选择]The purpose of the skirt or trunk in four-stroke cycle engines is to act in a similar manner to a （）.
A. crosshead
B. crown
C. piston rod
D. connecting rod
[名词解释]General purpose registers
[单项选择]A centrifugal compressor’s purge recovery unit（）
A. reclaims water
B. purges air without losing refrigerant
C. purges air with some loss of refrigerant
D. purges lube oil from the refrigerant
[单项选择]A purge recovery system is used in a centrifugal air conditioning or refrigeration system to （）
A. purge lube oil from the liquid refrigerant
B. recover water purged from the system
C. separate foul gases from the receiver
D. purge non-condensable gases without losing refrigerant
[单项选择]A more sophisticated pressure reducing valve incorporates a pilot valve which controls the fluid above the valve operating piston in response to downstream pressureThe bold and italic word “which” means （）.
A. a pressure reducing valve
B. a pilot valve
C. an operating piston
D. downstream pressure
[单项选择]A thermostatic expansion valve is properly controlling evaporator superheatAdjusting this valve to lower the superheat will result in a/an （）.
A. evaporator pressure decrease
B. evaporator coil over-feed
C. evaporator capacity increase
D. expansion valve diaphragm rupture
[单项选择]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
[单项选择]Overflow valve is used to （）
A. control the fluid flow through it
B. prevent the pressure before it over the specified valve
C. make the pressure after it steady
D. control the direction of oil flow
