Archive for August 2015

RUDDER WEAR DOWN

This refers to the measurements taken generally during a docking period to indicate excessive wear in the steering gear system particularly the rudder carrier. The significance of this is that for ram systems excessive wear can lead to bending moments on the rams. For rotary vane systems it can lead to vane edge loading.The readings taken are offered for recording by the classification society.

Trammel

This takes the form of an 'L' shape bar of suitable construction. When the vessel is built a distinct centrepunch mark is placed onto the ruder stock and onto a suitable location on the vessels structure, here given as a girder which is typical. The trammel is manufactured to suit these marks As the carrier wears the upper pointer will fall below the centrepunch mark by an amount equal to the wear down.




Rudder Clearance

Pads are welded to the hull and rudder. A clearance is given ( sometimes referred to as the jumping clearance). As the carrier wears this clearance will increase.



Steering gear Clearance

Direct measurement can be taken from the steering gear assembly. Shown below is one example, here the clearance will be seen to reduce as the carrier wears and impact his has on the system can be directly judged


Rudder wear down measurement:(Ram type Steering Gear ) 
At sea: 
1)Jumping clearance or bouncing clearance,measured between swivel block and upper ram fork end. (lmit is 19mm) 
2)Wear down clearance,measured between swil block and bottom ram fork end. (limit is 12-19mm) 

At docking: 
1)Bouncing clearance: measured betwen top ofrudde and jmpng bar. 
2)Wear down clearance: beween the bottom of rudder and reference mark.
Sunday, August 30, 2015
Posted by sanjay swain

REASON OF TURBOCHARGER DAMAGE

Diesel Engine Exhaust Turbocharger Failure 

Turbochargers are among the foremost technologically advanced engine element aboard ship. impeller blades of a medium sized turbocharger often rotate at the maximum amount as 400 revolutions per second. The outer edges of the rotor blades therefore move at 1.5 times the speed of sound.

In the method, the turbocharger digests contaminated exhaust gases of up to 700 degrees centigrade. Thus, the turbocharger may be a terribly sensitive piece of high-speed machinery incessantly serving in harsh conditions and underneath extreme strain. Being on the receiving end of gas flows, turbocharger damages are typically caused by the failure of varied upstream elements.


(1) Diesel engine inlet pressure to reduce main reasons:
(a) the compressor of the filter contamination.
(b) the impeller and vanes diffuser contamination.
(c) the supercharger turbo memory have more carbon deposit, spin resistance increase.
(d) the inter-cooler contamination, increased intake resistance.
(e) turbine exhaust not clear, this is because the pipe blockage, deformation caused by rotor speed rise is  not high.
(f)supercharger outlet pressure drop suddenly, it is because of bearing damage caused by.


(2) Compressor surge main reasons:
(a) diesel engine emergency cut-off or sudden unloading (urgent throttle back).
(b) the atmospheric temperature changes cause surge. In the summer of the supercharger with test, in winter could happen surge, this is because the temperature change make working point change and cause.
(c) compressor contamination, especially vanes diffuser contamination.
(d) a engine plant 2 sets of supercharger, Shared a piece of inlet manifold, when a cylinder does not work, can lead compressor surge.


(3) Diesel engine inlet pressure is too high. Generally speaking, the inlet pressure is too high in the supercharger itself is not the problem, but by the engine of the cause, the main reasons are:
(a) the vent valve leakage.
(b) because of engine fuel injection timing inappropriate or other causes for combustion period is too long, to drive a turbine heat increase, speed up, inlet pressure increase.


(4) Produce continuous abnormal sound: this kind of failure is due to the majority of rotor and shell as a result of the collision. Due to the rotor and shell assembly clearance is small, if installation misadjustment or bearing serious damage, then hitting.


(5) The lubricating oil temperature is too high (above 105 ℃) of the main reasons:
(a) the turbine oil, gas seal damage, high temperature gas into the oil chamber.
(b) the bearing damage.


(6) Oil leakage: compressor seal close to the edge of the impeller is low pressure area, easy to produce the oil leakage fault. Main reasons are:
(a) the lubricating oil return not free. The reason has return line congestion, return line sectional area is too small, pipe joint gasket inner hole diameter less than return line; Diesel engine in the crankcase oil level higher than standard, cause oil return difficult; Diesel engine crankcase ventilation blocking or cylinder seal bad, gas expell, make the crankcase internal pressure rise.
(b) the compressor end O ring damage or material ageing and lose sealing effect.


(c) turbocharger oil inlet pressure is too high. Normal pressure is 0.25 ~ 0400000 mpa, if pressure is higher than 0.6 million mpa, from exhaust muffler nozzle will find from the supercharger turbo end leakage oil.
(d) ring not installed correctly or damage.

Saturday, August 15, 2015
Posted by sanjay swain

ULTIMATE GREEN SHIPS

14 Technologies to Make the Ultimate Green Ship



The Shipping business is departure no stones right-side-out so as to contribute towards a greener marine atmosphere. At each producing and body levels, the maritime business is taking advantage of the newest technologies to make sure that new ships contribute as low as attainable to the world pollution.
Designing a Ship in present times has become a difficult task for currently a ship must be totally complied with new environmental rules and rules. some benchmark technologies have already been developed to achieve the final word goal of building a “Green ship” which might not solely suits the new environmental rules and rules however would additionally leave least attainable carbon foot-prints.

We have compiled a listing of 13 new technologies that if used along would lead to the ultimate green Ship of the longer term. they're as follows:

1.   No Ballast System: Ballast water convention by International Maritime Organization focuses on reducing the transit of sediments and small organisms of one territory to a different through the ballast of ships. so as to forestall this condition, plans of constructing a “No Ballast Ships” is underneath progress. A no ballast ship or similar system will drastically cut back this downside.

2.   LNG Fuel for Propulsion: it's same that LNG fuel is that the way forward for the Shipping business. LNG fuel helps in reduction of pollution from ships, and a mixture of LNG fuel with fuel can cause economical engine performance, leading to fuel saving.

3.   LNG Fuel for Auxiliary engine: Auxiliary engines on ships square measure main sources of power. what is more {they are|they're} one in all those machines that are continuous running aboard vessels. LNG fuel for such engines will drastically cut back pollution from ships.

4.   Sulphur Scrubber System: It’s not much attainable to phase-out usage of standard fuels in ships and thus reducing sulphur or SOx emission from the exhaust could be a answer that will be used extensively within the future. this could be achieved by putting in associate exhaust gas scrubber system whereby the sulphur is washed out from the exhaust gas of the engine leading to reduction of SOx up to ninety eight passed by with alternative harmful particles.

5.   Advanced Rudder and mechanical device System: A simple mechanical device and efficient rudder system will cut back the fuel consumption up to 4 the worries leading to less emission. Advanced styles of mechanical device and rudder systems are developed to not solely cut back the fuel consumption however additionally improve the speed of the vessel.

6.   Speed Nozzle: Speed Nozzles are typically utilized in little provide vessels and tugs to supply power to the ships. along side new style options of cargo ships, they will improve the propulsion potency of the ship by saving power up to approx five the concerns.

7.   Hull Paint: Another vital issue that may increase the fuel consumption of a ship and thus emissions is rising hull properties. Applying correct paint at correct hull space will cut back the resistance resistance of the ship leading to 3-8% of fuel savings.

8.   Waste Heat Recovery System: this technique is already in use for quite your time currently, however creating it a lot of economical will cut back the fuel consumption of the ship drastically up to 14 july of the whole consumption. The waste heat from the exhaust gases is used to heat and generate steam that successively is used for heating storage area, accommodation, heating oil etc.

9.   Exhaust Gas Recirculation: during this system, Roman deity emissions from the engine is reduced by recirculation of exhaust gas from engine cylinder with scavenge air that lowers the temperature of the combustion chamber. Some a part of the exhaust air is re-circulated and intercalary to scavenge air of the engine that reduces the oxygen content of the scavenge air along side temperature of combustion cylinder. With this methodology nox reduction of up to 80th is achieved.

10.  Water in Fuel: The addition of water in fuel simply before its injection into the combustion chamber will cut back the temperature within the cylinder liner. associate economical system for this could lead to nox reduction of up to 30-35%.

11.   Improved Pump and Cooling Water System: associate optimized cooling water system of pipes, coolers and pumps may end up in slashed resistance to the flow. this may cause savings of up to twenty of electrical power of the ship and fuel consumption up to 1.5 %.

12.   Sail and Kite Propulsion System: Sail and Kite system once used along side the traditional system will cut back the fuel additionally as nox, SOx and greenhouse emission emissions by thirty fifth. browse a lot of regarding these inexperienced propulsions system here.

13.   Fuel and photovoltaic cell Propulsion: The cell propulsion utilizes power from a mixture of fuel cells, star cells and battery systems. This helps in reduction of GHG emission to an excellent extent. browse a lot of regarding these propulsion systems here.

14. sandwich plate System (SPS): it's a method of composting two metals plates by bonding it with polymer stuff core.  This avoids usage of steel which needs further stiffening thus makes the structure lightweight weight and fewer vulnerable to corrosion. This technology will undoubtedly play an honest role in inexperienced ship usage method as SPS feature includes superior in commission performance and reduced through life maintenance.
Friday, August 7, 2015
Posted by sanjay swain

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