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The () pump discharges a nearly constant amount of liquid regardless of pressure.
A . mixed-flow
B . axial-flow
C . centrifugal
D . displacement
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The volatility of a liquid is the tendency of a liquid to ().
A . ignite
B . explode
C . asphyxiate
D . vaporize
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The pressure of a liquid leaving the pump can be referred to as the ().
A . total head
B . discharge head
C . net positive suction head
D . suction head
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Ullage measurements are taken from the top of the liquid to().
A . the base of the expansion trunk
B . the base of the ullage port
C . a line scribed within the ullage port
D . an above-deck datum,usually the top of the ullage hole
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Compared to the amount of concentrated foam liquid used,the amount of low expansion mechanical foam produced is().
A . 97 times greater
B . 94 times greater
C . 10 times greater
D . 2 times greater
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Which of the following centrifugal pump components converts the liquid kinetic energy of velocity to the potential energy of pressure?()
A . Impeller
B . Electric motor
C . Volute
D . Eye
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Which of the following influences the position of the interface between the liquid seal and the oil in a purifier?()
A、Height of the machine
B、Temperature of the liquid seal
C、Gravity disc
D、Bowl diameter
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What type of liquid is used in the liquid P/V breaker().
A . Hydraulic oil
B . Water-antifreeze mixture
C . Distilled water
D . Oil from the cargo
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The presence of bubbles in a refrigeration system liquid line may ().
A . promote refrigerant dehydration
B . be absorbed in the receiver
C . cause low condensing pressure
D . carry moisture and lead to corrosio
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Which of the following terms is used to identify the pressure of the liquid entering a pump?()
A . Suction head
B . Pump head
C . Discharge head
D . Total head
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The tendency of a flammable liquid to vaporize is indicated by its ().
A . ignition temperature
B . flash point
C . flammable range
D . convection index
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When liquid reaches the compressor of a refrigeration system through the suction line, the condition is called ().
A . flooding back
B . superheating
C . overflowing
D . recycling
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The () discharge a nearly constant amount of liquid regardless of pressure.
A . mixed-flow pump
B . axial-flow pump
C . centrifugal pump
D . displacement pum
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Which of the problems listed could be indicated if a sight glass in the refrigerant liquid line is full of bubbles?()
A . Proper refrigerant charge
B . Faulty expansion valve
C . Insufficient refrigerant
D . Solenoid valve stuck ope
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In a compression refrigeration cycle, the temperature of the liquid refrigerant experiences its greatest decrease in the().
A . evaporator
B . compressor
C . expansion valve
D . condenser
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Sub-cooling is a method of reducing the temperature of the liquid refrigerant below its ().
A . freezing point
B . floc point
C . condensing temperature
D . compression temperature
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The flash point of a liquid refers to the temperature ()
A . at which a liquid will give off inflammable vapors
B . at which a liquid will burn steadily
C . at which a liquid will explode
D . that a liquid must reach before it will flow readily
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Through a () pump, the liquid is transferred from the suction to the discharge by the mechanical variation of the volume of a chamber or chambers.
A . positive displacement
B . ejector
C . centrifugal
D . air compressor
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Which of the listed statements is a characteristic of the liquid charged power element used with thermostatic expansion valves?()
A . At the designed operating temperature, the liquid refrigerant charge has changed to a vapor
B . The liquid refrigerant tends to collect at the bellows or diaphragm and reduces the valve sensitivity
C . The sensing bulb is empty of liquid refrigerant charge at the designed operating temperature
D . The sensing bulb is never emptied of liquid refrigerant under normal operating conditio
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Which of the following statements is correct concerning the “flash point ” of a liquid?()
A . It is lower than the ignition temperature
B . It is the temperature at which a substance will spontaneously ignite
C . It is the temperature at which a substance, when ignited, will continue to bum
D . It is the temperature at which the released vapors will fall within the explosive range
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The most liquid of all assets is______.
A.the stock of commercial banks
B.Ml
C.intelligence
D.the debt of major corporations
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Which of the following has the greatest liquidity needs on average?
A、Investment companies.
B、Non-life insurance companies.
C、Banks.
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The following financial instruments are correctly ranked in the order of liquidity levels()
A.Cash, deposits, bonds, stocks
B.Cash, bonds, deposits, stocks
C.Cash, bonds, stocks, deposits
D.Cash, deposits, stocks, bonds
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液位标尺组态属于动态图形组态()。 The configuration of liquid level ruler belongs to the dynamic graphic configuration.()