A.The safety valve escape piping should be disconnected from the valve body and a blank inserted
B.The boiler vent valves should be opened
C.All hand-hole/manhole covers should be tightened up as much as possible to preclude any leaks
D.All of the above
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A.The boiler oil tank
B.The steam pipe
C.The fire side
D.The safety valves
A.oxygen in the water
B.poor boiler design
C.density too high
D.excessive steam demand
A.yellowish flame
B.golden yellow flame
C.white flame
D.brilliant white flame
A.condensate
B.a small amount of make-up feed
C.A and B
D.None of the above
A.yellowish flame
B.golden yellow flame
C.white flame
D.brilliant white flame
A.low water level
B.low oil pressure
C.excessively high fuel pressure
D.an improper air/fuel ratio
A.Reciprocating pump
B.Screw pump
C.Diffuser pump
D.Water-ring pump
A.discharge is continuous
B.it has no internal valves
C.upon accidental closing of discharge valve, excessive pressure will not build up
D.all of the above are true
A.between the suction and discharge
B.below the liquid supply
C.above the liquid supply
D.any of the above
Which of the following pumps are self-priming, and can deal with liquid from a level below the pump? ()
(1) reciprocating
(2) vane
(3) gear
A.(1)only
B.(1)and(2)
C.(1),(2)and(3)
D.(2)and(3)
最新试题
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump ().
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by ().
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of ().
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be ().
One cause of high head pressure occurring in a refrigeration system can be ().
A salinity indicator is used to determine the ().
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by ().
The output volume of a positive fixed displacement pump can be changed only by ().
An excessive charge of refrigerant in an air-cooled refrigeration system can cause ().
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its ().