Propeller is the most significant machinery system of the ship. No matter what type of propeller it is, ship owners never make compromises on such important equipment as it directly affects the efficiency and safety of the vessel. Here we discuss about fixed pitch keyless propeller renewal.
Operation of generators on ships
Hi friend! Today I would like introduce for you : "Operation of generators on ships" Generator Engine (G / E) have the function, the task of generating electricity to supply electrical appliances on board. Speaking of light, we often think of a combination of diesel (diesel engine) hybrid generator (Alternator)..
101 Important Things to Check While Starting Fuel Oil Purifier on Ships???
Every engine room machinery system needs systematic step-by-step starting and stopping procedures to ensure smooth running. The number of things to consider while handling ship’s machinery system, depends on aspects such as equipment type, making etc.
An outline of the Maritime Labour Convention 2006 (MLC 2006)
Dear friends! The world currently has about 1.2 million seafarers working on ships, transporting some 90% of global merchandise trade. Facing freight demand is increasing, raising the quality and ensure the rights and obligations of the crew working on the sea is a world problem being very interested. So, on 02/07/2006, at the 54th Conference of the ILO, with the participation of nearly 100 member states, has agreed to build the Maritime Labour Convention 2006 (MLC 2006).
Operating procedures bilge separator machine USH-20 of the company Taiko Kikai
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Types of Mechanical Measuring Tools and Gauges Used on Ships
Machinery onboard ships require regular care and maintenance so that their working life and efficiency can be increased, and the cost of operation, which includes unnecessary breakdowns and spares, can be reduced. For different types of machinery and systems, various measuring tools, instruments and gauges are used on a ship.
Saturday, June 23, 2018
Propeller is the most significant machinery system of the ship. No matter what type of propeller it is, ship owners never make compromises on such important equipment as it directly affects the efficiency and safety of the vessel. Here we discuss about fixed pitch keyless propeller renewal.
Construction - Advantages and disadvantages of Globe valves
Reasons for Cylinder Liner Wear
2) Due to corrosion.
3) Abrasion
4) Scuffing or Adhesion
Frictional Wear:
Corrosion:
– Burning of heavy fuel oil in the combustion space:
This happens because heavy fuel oil contains high sulfur content. During combustion, acids are formed inside the space which should be neutralised by cylinder oil which is alkaline in nature. The production of acids will be more if sulfur content is more, leading to the formation of sulphuric acid. Sulphuric acid is formed due to absorption of the condensate or moisture present inside the combustion space.
Abrasion
Adhesion or Scuffing
How Can Cylinder Liner Wear be Minimised?
2) By maintaining the correct grade of cylinder oil.
3) By supplying correct feed rate with load change dependent lubrication system
4) By avoiding ingress of moisture from the charge air.
5) By maintaining proper jacket water temperature.
6) By supplying good quality purified fuel oil inside the combustion chamber
7) By properly maintaining the fuel injector and fuel system for correct atomization and injection of fuel inside the chamber
8) By doing regular scavenge port inspection for early detection of piston ring wear and liner surface wear
How to Measure Cylinder Liner Bore Wear?
Procedure:
2. Cover the stuffing box hole to avoid debris falling inside crankcase
3. Remove the liner ring and clean the carbon deposits from top surface of the liner
4. Insert a ladder and carefully inspect the liner surface before gauging
5. The cylinder liner wear is measured by a standard template, which consists of strategically positioned holes, wherein the micrometer is placed and the readings are taken
6. The readings are taken for both port starboard and forward aft positions. This is done because the wear is not same in both direction and the cylinder liner ovality is checked.
How to Calculate Cylinder Liner Wear Rate and Ovality?
Thursday, June 21, 2018
Construction - Advantages and disadvantages of Globe valves
Installation Procedures
- Make sure the pipeline and flange faces are clean. Any foreign material such as metal filings, pipe scale, welding slag, welding rods, etc. can limit disc movement or damage the disc or seat.
- Gaskets are not required on resilient seated valves because they extend to both faces of the valve.
- Align the pipe-work, and spread the flanges enough to allow the valve body to be easily inserted between the flanges without contacting the pipe flanges.
- Check that the valve disc has been set to about 10% open so it doesn't become jammed in the fully seated position.
- Insert the valve between the flanges as shown, taking care not to damage the seat faces. Always lift the valve by the locating holes or by using a nylon sling on the neck or the body. Never lift the valve by the actuator or operator mounted on the valve.
- Place the valve between the flanges, centre it, insert the bolts and hand-tighten them. Carefully open the disc, making sure the disc does not contact the inside of the adjacent pipes.
- Very slowly close the valve disc to ensure disc edge clearance from the adjacent pipe flange.
- Fully open the disc and tighten all flange bolts as shown.
- Repeat a full close to full open rotation of the disc to ensure proper clearances.
Wednesday, June 20, 2018
Advantages of screw pumps:
+ Slow Speed, Simple and Rugged design
+ Pumps raw water with heavy solids and floating debris
+ Can run without water
+ No collection sump required = minimum head
+ Constant high efficiency with variable capacity
+ Pump capacity is self-regulating with incoming level
+ 'Gentle handling' of biological flock
+ Easy maintenance (no 'high skilled' staff required)
+Long lifetime ( > 20-40 years)
Disadvantages of Propeller / Centrifugal Pumps:
- High speed = increased wear
-Possible blockages at reduced capacities
- Heavy solids cannot be pumped
- Floating debris is not pumped
- Dry running is fatal
- High friction losses in pipes
- Mechanical seals need regular adjustment
- Lifting facilities required with each maintenance
- Higher skilled maintenance staff required
- Submerged motors cause more trouble than dry motors
Advantages of screw pumps and Disadvantages of Propeller / Centrifugal Pumps
What is the difference between pumps?
How is the screw pump? Advantages of screw pump:
1. Wide range of flows and pressures
2. Wide range of liquids and viscosities
3. Built-in variable capacity
4. High speed capability for freedom of driver selection
5. Low internal velocities
6. Self-priming with good suction characteristics
7. High tolerance for entrained air and other gases
8. Minimum churning or foaming
9. Low mechanical vibration, pulsation-free flow, and quiet operation
10. Rugged, compact design - easy to install and maintain
11. High tolerance to contamination in comparison with other rotary pumps
Disadvantages of screw pump:
1. Relatively high cost because of close tolerances and running clearances
2. Performance characteristics sensitive to viscosity change
3. High pressure capability requires long pumping elements
Construction - Advantages and disadvantages of Globe valves
Hello friend! Today I would like introduce for you: " What is the difference between pumps?"- The type of liquid you wish to pump
- The distance you wish to move the liquid
- The volume you need to achieve over a specific time frame
Centrifugal Pumps
- Axial Flow: The axial flow impeller discharges fluid along the shaft axis. For this reason an axial flow pump is by definition not "centrifugal" in its pumping action.
- Radial Flow: The radial flow impeller discharges the fluid radially at 90° to the shaft axis.
- Mixed Flow: The mixed flow impeller discharges fluid in a conical direction using a combined radial and axial pumping action – as suggest by the title
- Positive Displacement Pumps
- This type of pump creates an expanding cavity on the suction side of the pump and a contracting cavity on the discharge outlet. This difference creates pressure which pulls and pushes a fluid simultaneously, exerting enough force to create flow.Positive displacement pumps come in two designs:
- Reciprocating: In this design, the suction is created by a piston which plunges into and pulls out of the material. Valves are used to ensure that the flow only moves in one direction. A reciprocating design therefore pulses the liquid at identical intervals
- Rotary: A rotary design uses two gears which mesh together. The movement of the gears creates high pressure on the discharge side which creates flow
- Due to the design, positive displacement pumps are better at handling viscous material. There are many different types of positive displacement pumps, such as:
- Rotary lobe pump
- Progressing cavity pump
- Rotary gear pump
- Piston pump
- Diaphragm pump
- Screw pump
- Gear pump
- Vane pump
- Peristaltic hose
Thursday, June 14, 2018
Principal of Centrifugal pumps
Operation of generators on ships
Advantages of screw pumps and Disadvantages of Propeller / Centrifugal Pumps
What is the difference between pumps?
How is the screw pump?
Differences Between Diesel Engines and Gasoline Engines
Routine Checks
8. If the sewage treatment plant is fitted with UV disinfectant system instead of the chlorination system, the UV lamp has to be changed as recommended by the manufacturer.