單項選擇題The boiler water alkalinity in a coil-type auxiliary boiler should be maintained at the pH recommended by the boiler manufacturer to()

A.precipitate silica from solution
B.reduce corrosion in the heating coil
C.prevent clogging and erosion in the coil
D.maintain zero water hardness


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1.單項選擇題Diesel engine waste heat boiler construction is usually of the fire-tube or()

A.cyclone furnace boiler type
B.dry back boiler type
C.water-tube type
D.critical circulation boiler type

2.單項選擇題Auxiliary boilers are divided into several classifications, one of which is()

A.fire-tube controlled circulation
B.fire-tube supercritical circulation
C.water-tube natural circulation
D.water-tube express circulation

3.單項選擇題Which of the lists forms of heat transfer, if any, is illustrated by the flow of combustion gases through a boiler?()

A.Natural convection only
B.Forced convection only
C.Both natural convection and forced convection
D.None

4.單項選擇題Auxiliary boilers can be classified as()

A.water-tube natural circulation boilers
B.fire-tube boilers
C.water-tube forced circulation boilers
D.all of the above

5.單項選擇題When the tilting box of a variable stroke axial-piston pump is perpendicular to the pump shaft, which of the following conditions will exist?()

A.The pistons reciprocate
B.The ‘B’ end cylinder barrel rotates
C.There is no fluid flow
D.Power is transmitted hydraulically