competence 4

100問 • 1年前

問題一覧

Which of the following admits air to the piston of a cylinder rely valves in a correct sequence for engine starting?

Starting Air Distributor

A twin-screw, rotary, positive displacement pump is provided with timing gears. If it were posible to change the lead (pitch) of the screws, which of the following statements would erpresent the true effect on the pump characteristics.?

The shorter the lead, the higher the pressure potential

Excessive vibrations created by the main propulsion machinery are detrimental to which equipment listed below

navigation

How is dissolved oxygen in boiler feed water minimized ?

Maintain high feed water temperature

When fuel viscosity in the service tank needs to be reduced before the atomizer, what should be done?

increase the heater steam supply

What is known as an air motor induced in a four-cycle diesel engine cylinder engine cylinder to improve air fuel mixing ?

Turbulence

Dirty condenser in a refrigeration system would indicate ?

high pressure discharge

The rotary motion of a diesel engine crankshaft is obtained from the up and down motion of the piston via the ?

connection rod or piston rod

What part of an engine transmits the reciprocating motion of the piston to the driven unit in the form of rotary motion ?

crankshaft

How is the pressure and temperature affected in a diesel engine cylinder during compression?

Pressure and temperature increase

If condensate is accumulated in the steam side of a fuel oil heater, it could result in ?

corrosion

Why should the boiler fire side be kept free from soot accumulations ?

soot insulates the boiler heating surfaces

What is the use of follow-up gear on an electro-hydraulic steering gear?

Takes the pump off stroke when the desired rudder angle is attained

The most common diesel engine fuel system problems are caused by ?

dirty fuel

When a fuel injection nozzole overheated which of the problems listed below can be expected ?

The fuel metering will vary

An incinerator is a waste disposal unit that will burn ?

solid material and all types of liquid waste

Reduced capacity, vibration and noise at the centrifugal pump suction due to vapor pockets in the fluid being pumped is caused by

cavitation

What will be the result if carbon deposits accumulates in the burner throat and diffuser rings of boiler ?

decrease boiler efficiency

Rapid fluctuations of absolute pressure in the last effect of a multi-effect submerged tube distilling, plant will tend to cause ?

Priming with increased salinity of distillate

Why are relief valves of fuel service pump for boiler burners installed ?

To protect the pump from high discharge pressure

Which operating condiion of a diesel engine is indicated by excessive firing pressures?

Overload

What will happen if the needle valve in a fuel injection nozzle sticks open?

The nozzle will overheat

Which of the listed turbocharger component increases air density and helps improve engine operating efficiency ?

Air cooler

In addition to a nozzle, a fuel oil atomizer uses which of the listed parts?

Burner cone

When an engine coupled with the large vibrational shocks that act on the shaft, there could be a permanent damage to the propeller shafts. Why?

Because of the intermediate shaft weight

What does an unusual or new vibration in the hull or propeller shafting indicate ?

Propeller unbalance

What happens when oil is heated up?

The specific gravity increases

Schedule of soot blowing for economizers is done for at least?

Three times a day

Which items on the list could reduce high salinity in a steaming boiler ?

using the continous blowdown

In the water tube boiler, the fire in the furnace is located at the ?

outside the tubes

On a medium pressure, differential piston, reciprocating air compressor, lubrication of the piston/cylinders is usually accomplished,

with metering type cylinder lubricators

A badly leaking refrigeration compressor discharge valves will cause ?

constant running of the compressor

A change in the degree of fuel atomiztion in a diesel engine cylinder has the greatest effect on the ?

combustion in that cylinder

Which of the following is the purpose of the diffuse in a burner assembly ?

To shield the flame from the incoming air blast while allowing mixing of fuel and air

If the discharge valves is closed before the drive motor is stopped, which type of pump will most likely be damaged?

Gear pump

Diesel engine crankcase oil mist detectors are designed to analyze?

the concentration of oil vapours in the crankcase

Burned gas from each cylinder is directed to the exhaust manifold which is part of ?

2-stroke engine

When chemical energy of the fuel is converted to thermal energy during boiler operation, the convertion process occurs where?

furnace

In bunker tanks, which of the following tanks is used in storing fuel ready for immediate use for starting up the diesel engine?

Service tank

The boiler water having a pH reading of 7.0 is said to be ?

neutral

What is a practical way of checking for excessive fuel injection in one cylinder of an operating diesel engine ?

Check the cylinder exhaust temperature frequently

Positive displacement helical gear pumps are well suited for pumping oil because ?

they are self-priming and produce high suction lift

The measured temperature indicate the ?

level of heat intensity

Which of the following components is directly connected to the propellers and lies mainly encased in the stern tube?

Tail shaft

In a mechanical compression refrigerating system, what is the main cause of a very low discharge pressure?

Insufficient refrigerant in the system

In air conditioning system, which part of the system where the refrigerant begins to boil and flash into gas ?

Evaporator

Purging air from a hydraulic oil system is necessary when?

system has been drained and filled with new oil

Regarding the low pressure evaporator steam control orifice win the live steam supply line, the steam at the oulet of the orifice if not properly conditioned will be developed as ?

superheated steam

In a large slow-speed propulsion diesel engine, the force applied to the piston is

against the crosshead during the power and compressions strokes

Why is it important to apply proper filtering and straining of diesel fuel oil?

fuel injectors may be damaged by foreign particles in the fuel oil

Which of the following methods is used to counter axial thrust in a single flow reaction turbine?

A dummy piston and cylinder at the turbine inlet end

Which is the function of a boiler diffuser assembly ?

Serves to mix the air evenly with the fuel

An internal bypass is provided on some hydraulic system suction strainers to help reduce the posibility of ?

pump cavitations

What is the function of boiler variable capacity pressure regulator in atomizing fuel inside burner

Provide wide range of combustion

Fuel injectors used in heavy fuel oil systems are usually provided with cooling to reduce ?

carbon accumulation on the nozzles

Some diesel engines are fitted with a thermometer in the cooling water outlet from each cylinder. If the cooling temperature from an individual cylinder begins to rise what hould you suspect ?

That there is an overloading of cylinder

Centrifugal pumps, used to handle hot liquids, must have a minimum flow through them under all operating conditions. This flow serves to ?

prevent overheating and vapour bound conditions

Which of the following will happen if the fuel oil heater attains excessively high temperature?

Carbon deposits will build up in the surfaces

Excessive scale formation in a distilling plant may result from?

Improper vacuum regulation

What is the effect if fuel oil tanks of a vessel is half full ?

free surface effect

Scavenging trunks are more prone to fire because they are ?

accumulating oily substance

In case Engine room is unmanned and Diesel Engine is running, when the temperature of cooling, water outlet is one degree above the limit in long period of time. What is the next immediate better thing to do ?

Check the setting of temperature controller

Emergency diesel generator day tank should always be kept full to reduce the possibility of ?

moisture formation from condensation

The boiler feedwater control valve varies the relationship between steam and water flow during periods of

steady boiler load

It is a form of energy which crosses the boundary of a system during a change of state produced by a difference of temperature between the system and its surroundings

Heat

The high pressure cut-off switch will stop the refrgeration compressor when there is ?

a stoppage of condenser cooling water flow

In a low pressure air compressor, the loss of volumetric efficiency normally results from?

heating of the air leaving the cylinders

As found in a basic pneumatic automatic combustion control system, the function of standarizing, relay is to

introduce a control for maintaining constant steam pressure regardless of boiler load

An air compressor is equipped with an intercooler and an aftercooler to ?

Increase compressor efficiency

In hydraulic system, with an increase in temperature, what will happen to the volume of hydraulic fluid?

expand

In a diesel engine, the fuel consumption is expressed in ?

grams per hoursepower per hour

Which of the following controls the amount of fuel atomized by a return flow oil burner?

fuel oil return valve

Machinery diving fuel oil transfer and fuel oil service pumps must be fitted with a remote means of stopping the machinery from ?

outside the space concerned

If an air compressor is used to supply air primarily to the combustion control system and other pneumatic controllers, the entire system is known as the

control air system

Which of the following characteristic that determines the temperature to which fuel must be heated for proper atomization is ?

viscosity

Stern tube is used to ?

support and seal the propeller shaft

Differential needle valves used in fuel injectors are directly closed by what?

spring force

An excessive pressure differential across a lube oil strainer could indicate the ?

upside down strainer needs cleaning

The by-products of oxidation, as a result of water contamination of hydraulic oil, are generally ?

gums, varnishes, and acids

The action should take when water is found in the fuel oil setting tank is to ?

shift pump suction to an alternate setting tank

To what purpose why is strainer install on hydraulic system?

To prevent solid particles from entering the pump

A mooring winch should be equipped with mechanical brakes capable of holding,

the full braking strength of the mooring line

You observed an efficiency drop caused by compressor fouling of the gas turbine, what is the most effective counter measure to carry out ?

Off-line washing

What will happened to air compressor unloading system if all of the air charge has been lost from ship service air receiver ?

Fail to work but the compressor having no load will start with little or no difficulty

Which part of a diesel engine that fuel is admitted into the cylinder combustion chamber ?

injector nozzle

The dimension of the thinnest hydrodynamic film developed within a full journal bearing, when all other factors remain constant, depends upon the ?

fluidity of the lubricant

Diesel engine jacket water is used in the fresh water distillation process as the ?

means of heating the feedwater

Nozzle diaphragms are installed in pressure-compounded impulse turbines to

hold the nozzle of the stage and admit steam to moving blades

In the Hydropore tank, What is the device to starts/stop the pump ?

Pressure switch

Gas turbine has operational flexibility. Which of the following is the reason?

Swift start up, no warm up or idling period is required

What is the reason why steam prssure reduces its pressure while accomplishing work in the engine or turbine?

The steam expands in volume

Before loosening pump covers how should the pressure be checked ?

air vent valve open and clear

What type of engine uses a high cetane number ?

Small, high speed

What is the importance of the control box of a differential gearsystem in a steering gear system?

It compares the bridge signal to the actual rudder angle through the follow up gear

If the water level cannot be seen in the lower part of the boiler gage glass, which of the following actions must be carried out immediately ?

Secure the boiler fires

The net positive suction head of a boiler centrifugal feed pump should be calculated over and above the

feedwater vapor pressure

A reading of zero on a Bourdon tube instrument generally means ?

equal to atmospheric pressure

Which significant combustion elements of fuel oil is a major source of air pollution ?

Sulphur

If a higher than normal water level is observed through the inspection port of a low pressure distilling plant, you should suspect ?

Improper vacuum

100

Air trapped in the hydraulic fluid of a steering system would be indicated by :

erratic rudder response

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