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Tappet clearance or Rocker clearance It is the clearance given between between the top of the valve spindle and Rocker arm. It is given for proper closening of valve at its operating temperature. It is actually given by manufacturer and can be adjusted when engine is cold. A normal procedure is taken out for the given unit piston should be at TDC in the power stroke and it should be checked through the push rod. Significance of the clearances: When the clearances is too small valve will open early and closes late. While when the clearances is too large it will open late  and closes early .

1. What is Thermodynamics ? Ans. It is branch of physics concerns  with heat and temperature and having relations with the energy and work . 2. What is difference between heat and temperature? Ans.                       HEAT It is a form of energy and it measures the total energy of molecules of the substance which is the sum of kinetic energy and potential energy. It's SI unit is joule and calorie in cgs unit.                                                        TEMPERATURE It is measure of  degree of hotness and coldness of a body which is the average kinetic energy of the molecules of the body . ...

First law of thermodynamics   is regarding  conservation of energy adapted for thermodynamics system . " It states that for an isolated system total  energy of the system is remains constant . It can be transformed from one form to another but can neither be created nor destroyed . " * Mathematically ,                      ΔU = Q - W " It states that the change in internal energy of the closed system is equal to the amount of heat supplied to the system minus the amount of working by the system on surrounding." Second law of thermodynamics It gives general principle for the direction of  heat transfer and attainable efficiencies of heat engines. Kelvin-planck statement for Heat engines It is impossible to extract all the heat from the hot reservoir and used into useful work , there will be certainly  heat exhausted to the surrounding . And whic...

It is an international freight index or scale is  for calculating the freight of the oil cargo which is being carried through sea. It includes expenses such as port fees , transit charges , voyage time and bunker cost. It is expressed in dollars per tonne. Uses : : >It is used for calculating the freight rate for oil tankers and product tankers . :> It is used as a calculating tool for charterer,  brokers  ,oil refining companies and ship owners . Note : Rates are revised annually on the basis of bunker cost , exchange rate and Port charges etc.

It is a small separate generator which supplies the electric power for emergency load in the event of main power supply failure. It is located outside the main and auxiliary machinery space and not forward of the collusion bulkhead. It has own switchboard near vicinity. It is provided with independent means of automatically starting,( by air or battery) to ensure immediate run up following a main power failure and repeated starts of at least 3 times, and further attempt can be made within the 30 minutes temporary battery life Adequate and independent supply of fuel with a flash point of not less than 43°C (109.4°F) Must be able to be started in cold condition up to 0°C (32°F) For cold weather, JCW system must be treated with anti-freeze agent, and heating arrangement provided. Emergency generator Maintenance 01) Every Saturday, emergency generator must be tested run 02) Air bottle pressed up or starter battery fully charged, at all-time 03) Changeover the...

Wire drawing effect : It is erosion or scoring of valve seat and disc material of the valve . Causes : 1. Due to differential pressure across the valve . 2. Thermal and mechanical damages . Effects : Valve is unable to isolate the line and fails in sealing . Gas and liquid will leak from the wire and scratch like groove .

Creep is phenomenon in which time dependent deformation takes place. Eg. When an wire is installed it is straighten while after sometime due to its own weight sagging takes place. Fatigue failure is a phenomenon in which components subjected to cyclic stress . It can be analyzed with SN Curve. Approx 90% of the machinery failure happens due to this . Eg. Tie rod of main engine .

1. How do will know that turbine side nozzle got chocked ? Ans. Rpm of the turbocharger will get reduced. 2. Which type of turbine is of turbocharger has ? A. Impulse type B. Reaction type  Ans. A ( it has got single stage  impulse type turbine ) 3. How do will reduce the vibration of turbocharger? Ans . Use of Lacing wire . 4. What is K mark of turbocharger? Ans. It is the distance between the compressor side shaft and the bearing cover. It is given at the bearing cover of compressor side.( 21.7 mm generally for the smaller one) 5.How to clean the rotor side of compressor ? Ans. With the help of soap solution . [ Don't use any chemical and steam etc. because it is of aluminium having melting temperature of 200℃.] 6. What is the material of rotor blade of turbine side and blade of compressor side ? Ans. Nickel Chrome Alloy (Nimonic Alloy) of turbine blade and Aluminium alloy or expensive titanium of compressor side blades. 7. What is the purpose of fixed ...

Thermal efficiency = (T1-T2)/T1                          Where , T1 = The higher absolute temperature in the cycle                                             T2 = The lowest absolute temperature in the cycle   Thus to increase the thermal efficiency the temperature difference (T1-T2)  must be increased .             We can understand it from the given diagram .                     

Pairing disc in purifier It is a stationary impeller mounted in a chamber at the neck of the bow. It function is convert the rotating energy into a pressure head. Source: MIN ZAR TAR

1. Change the gravity disc of correct size which is smaller for diesel . 2. Heater bypass valve should open . 3. Close the steam  inlet and outlet valve to the heater . 4. Drain the heater.

1. Open up the purifier and place the blind disc at the bottom of disc stack. 2. The water outlet is blocked by seal on the gravity disc. 3. Blank off sealing water inlet line .

It is an Important part of a purifier which is used to create oil and water interface line . With the help of Nomogram for the required throughput , separating temperature and density of oil correct size of gravity disc is selected .

Clarifier 1. It is a centrifuge which is used to separate solid impurities from the oil.  2. Gravity disc is not present in it . It has sealing ring. 3. Blind Disc is present at the bottom. 4. It has one outlet for cleaning oil. 5. It requires no sealing water . Purifier 1. It is a centrifuge which is used to separate finer solid impurities and water from the oil. 2. It has gravity disc to create oil and water interface. 3. Blind disc is present at the top . 4. It has two outlets one for clean oil and other for water. 5. It requires sealing water .

Attemperator are fitted in order to keep the steam temperature in the final stages of the superheater within certain desired limits . This is done for two main reasons . 1. The most important is the protection of the superheater tube material from the effects of overheating. *Mild steel superheater tubes tubes should not be subjected to steam temperatures in excess of 455℃. 2. The formation of bonded deposits on superheater tubes can be reduced if steam and gas streams within certain temperature ranges are prevented from coming into contact of each other. De-Superheater is used to reduce the temperature of a quantity of superheated steam and make it suitable for used in auxiliary services requires low temperature or saturated steam . *The reason for doing this way rather than by taking the saturated steam direct from steam drum , is to protect the superheater , these must be protected against overheating under all conditions of load by circulating steam through them . *Al...