更多"When securing a flash-type evaporat"的相关试题:
[单项选择]When the water produced from most evaporator is supplied for drinking purpose, it must be treated to ensure it is biologically pure and ().
A. slightly acidic
B. slightly alkaline
C. no salty
D. slightly bitter
[单项选择]When a vacuum boiling evaporator works, the hot jacket water will pass over the tube stack and () the sea water passing through the tubes.
A. dispose
B. dissolve
C. heat
D. dissipates
[单项选择]When a flash-type evaporator is to be secured for an extended period of time, the entire unit should be drained, cleaned, and ().
A. completely filled with saltwater
B. filled with de-scaling compound
C. tightly closed to exclude air
D. vented to the atmosphere
[单项选择]When securing an AC generator, you should FIRST ().
A. open the generator circuit breaker
B. switch the voltage regulator to “manual”
C. decrease the field excitation to minimum
D. reduce the load on the unit
[单项选择]When securing a hook to the end of a wire rope you should use().
A. A bowline knot
B. A long splice
C. An overhand knot with a wire rope clip
D. Wire rope clips with a thimble eye
[单项选择]Scale accumulation on evaporator heat exchange surfaces ().
A. increases brine density
B. increases distillate salinity
C. reduces metal corrosion
D. reduces heat transfer
[单项选择]Constant superheat is maintained at the evaporator outlet of a refrigeration coil by a()
A. solenoid valve
B. low pressure cutout switch
C. king valve
D. thermal expansion valve
[单项选择]Less scale formation occurs in a flash evaporator than in a submerged tube evaporator because ().
A. the distillate produced has greater purity
B. no boiling occurs on heat transfer surfaces
C. evaporation occurs at a higher rate
D. the incoming feed is at a higher temperature
[单项选择]The refrigerant leaves the evaporator of a refrigeration system as a low pressure ().
A. sub-cooled liquid
B. high temperature liquid
C. oil saturated liquid
D. superheated vapor
[单项选择]The refrigerant flows through the evaporator, where it () heat from the refrigerated space.
A. extracts
B. releases
C. gives no
D. absorbs no
[单项选择]A flash-type evaporator discharges heated seawater into a chamber that is maintained at a pressure than the vapor pressure of the entering heated seawater, and subsequently the flashed water vapor thereby produced()
A. lower condensing
B. higher cooling
C. lower cooling
D. higher condensing
[单项选择]The steam coils in a high pressure evaporator used for saltwater service should be de-scaled with ().
A. a needle gun
B. soap and water
C. a wire brush
D. a chipping hammer
[单项选择]The demisters installed in a flash-type evaporator serve to ()
A. deaerate the first effect distillate
B. filter the condensed flash vapors
C. deaerate the first and second effect distillate
D. remove small water droplets entrained in the flashed vapor
[单项选择]In the operation of a flash type evaporator equipped with air ejectors,the air and non- condensable gases are evacuated directly from the ().
A. first stage flash chamber
B. second stage flash chamber
C. first stage after condenser
D. second stage distilling condenser
[单项选择]In a flash type evaporator, all saltwater headers are vented through individual vent cocks to the().
A. saltwater heater shell
B. second-stage condenser
C. atmosphere
D. second-stage flash chamber
[单项选择]The flash-evaporator is different with the submerged-tube evaporator in that for the former()
A. Water is heated into vapor on heating surfaces
B. Water is vaporized by pressure difference
C. There are no heating-transfer surfaces
D. There are more heating-transfer surfaces
[单项选择]With a vacuum boiling evaporator, the remainder of sea water fed to the evaporator is pumped out by ().
A. a brine pump
B. an air ejector
C. a feed pump
D. distillate pump
[单项选择]In a flash type evaporator, the brine overboard pump is vented directly to the()
A. saltwater heater shell
B. the condensation of the saltwater feed
C. air ejectors, eductors, or a separate vacuum pump
D. condensation of the distillate
[单项选择]The efficiency of a flash type evaporator can be increased by()
A. lowering brine discharge density
B. decreasing the absolute pressure of each stage
C. increasing the saltwater feed heater temperature
D. increasing the pressure at the spray pipe