- In a positive displacement reciprocating pump, the use of the accumulator is to?
- Steady the flow in the discharge section of the pipe.
- Dampen the pressure surge on discharge side.
- To always maintain a discharge head on the pump.
- Both options A & B
- The process of depositing chromium on to steel surfaces by diffusion coating is known as :
- When running TWO centrifugal Pumps in parallel, Flow rate”Q” is increased.
- May Be
- I Don’t know
- A refrigerant compressor will run continuously when there is
- Too heavy cooling load on the system
- Air in the system
- Insufficient refrigerant in the system
- Any of the above
- Which of the following types of boiler burners have maximum turn down ratio? (Y-jet, 20:1)
- Pressure jet type
- Spinning cup burner
- Spill type burner
- Y-jet type burner
- Copper tubing is used in Refrigerant system because
- It has less internal resistance
- It is cheaper compared to other materials
- It is easier to check leaks in copper based system
- None of the above
- Which of the following is a true statement? (Choose more than one option if true)
- Mild steel will be subject to preferential corrosion when in electrical continuity with stainless steel in presence of an electrolyte
- Stainless steel will be subject to preferential corrosion when in electrical continuity with Mild steel in presence of an electrolyte
- Copper will be subject to preferential corrosion when in electrical continuity with Mild steel in presence of an electrolyte
- Zinc will be subject to preferential corrosion when in electrical continuity with Aluminium in presence of an electrolyte
ANS.: A, D
- Motor stator winding badly contaminated by dirt, oil and grease should be cleaned by:
- High pressure compressed air
- Suction or vacuum cleaning
- Brushing, spraying or immersion in an approved cleaning solvent
- Immersion in fresh water followed by drying
- Aluminium being lower than zinc in Galvanic series provides lesser protection to steel compared to the zinc coating. Which one of the following is a true statement?
- Aluminium coating provides good corrosion protection compared that of zinc at elevated temperatures
- Zinc is always preferred over aluminium coating irrespective of the temperature of metal surface
- Aluminium is never used as coating material
- Aluminium reacts with steel , so cannot be used for coating steel
- Impingement corrosion is a
- Physical action
- CHEMICAL action
- Physical and chemical action
- None of the above
- Which of the following is NOT a correct point for sampling of system lube oil for on board or shore analysis?
- Purifier outlets
- Inlet or outlet of L. O. coolers
- Tank drains
- In which of the following types of refractory failure, softening of the refractory bricks takes place due to presence of sodium/vanadium in fuel?
- Shrinkage cracking
- A thin layer of electrolyte trapped in small pits on a metal surface, and remaining stagnant over a period of time, may cause:
- Bimetallic corrosion
- Crevice corrosion
- Corrosion fatigue
- Which of the following statements is False about cleanliness of electric motors?
- External motor body cleanliness of totally enclosed is important since the body helps to dissipate heat generated
- Dirt, oil, grease and moisture are primary culprits in deterioration of insulation of stator windings of a motor.
- High-pressure dry compressed air cleaning is preferred over suction cleaning for stator windings.
- Dry compressed air at a high pressure can drive in dirt inside windings instead of removing them.
- Surface preparation of steel surfaces, prior carrying out painting isimportant because:
- Any rust and contaminant inclusions may cause local paint film breakdown
- Too much paint will be consumed if surface preparation is not carried out
- Surface will be very rough if proper surface preparation is not carried out
- Surface preparation deposits a chemical onto steel surface which reacts with paint film and causes
- Increasing the rotational speed of a cargo pump the pump flow rate will:
- Increase in direct proportion to the increase in speed
- Decrease in direct proportion to the increase in speed
- Flow rate doesn’t depend upon speed
- After maintaining correct discharge pressure, soon ceases to discharge water what are possible cause?
- Pressure gauge wrong
- Pump sucking air
- Discharge valve throttled
- Casing wear ring is worn
- The flow rate through a F.O. transfer pumpwill not be affectedby which of the following factors?
- Low F.O. temperature
- Low sounding in F.O. tank
- Internal leakage within the pump
- Leaking discharge valve