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Machinery spaces piping system - various fittings
Mud boxes are fitted into the machinery space bilge suction piping. The
mud box is a coarse strainer with a straight tailpipe down to the bilge
. To enable the internal perforated plate to be cleaned
when necessary, the lid of the mud box is easily removed without
disconnecting any pipework.
Suction pipes in tanks should be arranged with a bell mouth or foot.
The bell end or foot should provide an inlet area of about
one-and-a-half times the pipe area.
It should also be a sufficient distance
from the bottom plating and nearby structure to provide a free suction
area, again about one-and-a-half times the pipe area.
A steam trap does as its name implies and permits only the passage
of condensed steam. It operates automatically and is situated in steam
drain lines. Various designs are available utilising mechanical floats
which, when floating in condensate, will enable the condensate to
discharge . Other designs employ various types of
thermostat to operate the valve which discharges the condensate.
Fig:An Expansion bellows piece
An expansion piece is fitted in a pipeline which is subject to
considerable temperature variations. One type consists of a bellows
arrangement which will permit movement in several directions and
absorb vibration . The fitting must be selected according to
the variation in system temperatures and installed to permit the
expansion and contraction required in the system.
Drains are provided in pipelines and usually have small cocks to open
or close them. It is essential that certain pipelines are drained regularly,
particularly in steam systems. When steam is admitted to a pipeline
containing a reasonable surface of water it will condense and a partial
vacuum occur: the water will then be drawn along the pipe until it meets
a bend or a closed valve. The impact of the moving water in the
pipework will create large forces known as 'water hammer', which can
result in damage to pipework and fittings.
Piping systems for cargo ship's machinery spaces
A ship's machinery space contains hundreds of metres of piping and
fittings. The various systems are arranged to carry many different
liquids at various temperatures and pressures. The influences of
operational and safety requirements, as well as legislation, result in
somewhat complicated arrangements of what are a few basic fittings.
Valves, strainers, branch pipes, etc., are examples of fittings which are
found in a pipe system.
Machinery space pipework is made up of assorted straight lengths and
bends joined by flanges with an appropriate gasket or joint between, or
very small-bore piping may use compression couplings. The piping
material will be chosen to suit the liquid carried and the system
conditions. Some examples are shown below .
Where piping is to be galvanised, the completed pipe with all joints
fully welded is to be hot dipped galvanised. The pipes are supported
and held in by hangers or pipe clips in such a way as to minimise
vibration. Steam pipes or pipes in systems with considerable temperature
variation may be supported on spring hangers which permit a
degree of movement. An alternative to spring hangers is the use of
expansion loops of piping or an expansion joint.
Machinery space pipework material
Waste steam :Carbon steel to BS 3601
SW circulating :Aluminium brass
Wash deck and firemain :Carbon steel to BS3601 — galvanised
Bilge and ballast :Carbon steel to BS3601 - galvanised
Control air :Copper
Starting air :Carbon steel to BS 3602
All system pipework throughout the vessel is to be periodically inspected for condition and security in a systematic manner and be reported upon in the PMS. It is of utmost importance to include in these inspections the pipework located in those spaces that are remote, poorly lit and may be difficult to access.
Particular attention should be paid to sea water pipework which may be subject to corrosion and wastage on both internal and external surfaces, and opportunity should be taken whenever possible, and certainly during drydocking periods, to establish pipewall condition by hammer testing and visual inspection of internal surfaces in locations where valves or pipe sections have been removed for routine maintenance, repair or replacement.
Defective pipework is to be replaced at the earliest convenient opportunity.
- Various valves arrangement for machinery spaces piping system Straight-through cocks, Globe valve,Non-return valves,gate valves,Relief valves, quick closing valves, valve chests....
- Mud boxes, Suction pipes, Steam traps, Expansion pieces & Drains for Machinery space piping system The mud box is a coarse strainer with a straight tailpipe down to the bilge..Suction pipes in tanks should be arranged with a bell mouth or foot..An expansion piece is fitted in a pipeline which is subject to considerable temperature variations..Drains are provided in pipelines and usually have small cocks to open
or close them.....
- Reciprocating displacement pumping system for ships use The displacement pumping action is achieved by the reduction or
increase in volume of a space causing the liquid (or gas) to be physically
moved. The method employed is either a piston in a cylinder using a
reciprocating motion, or a rotating unit using vanes, gears or screws.
- Centrifugal pump principles and working procedure
In a centrifugal pump liquid enters the centre or eye of the impeller and flows radially out between the vanes, its velocity being increased by the
- How a pneumatically control valve works ?
Many pneumatic devices use a nozzle and flapper system to give a
variation in the compressed air signal.A typical pneumatic control valve is shown in Figure . It can be considered as made up of two parts—the actuator and the valve. A flexible diaphragm forms a pressure tight
chamber in the upper half of the actuator and the controller signal is fed
- Domestic water systems for general cargo ship Domestic water systems usually comprise a fresh water system for
washing and drinking and a salt water system for sanitary purposes
. Both use a basically similar arrangement of an automatic
pump supplying the liquid to a tank which is pressurised by compressed
- Bilge and ballast systems for general cargo ships
The bilge main is arranged to drain any watertight compartment other
than ballast, oil or water tanks and to discharge the contents overboard.
The number of pumps and their capacity depend upon the size, type
and service of the vessel.....
Marine machineries - Useful tags
Marine diesel engines ||Steam generating plant ||Air conditioning system ||Compressed air ||Marine batteries ||Cargo refrigeration ||Centrifugal pump ||Various coolers ||Emergency power supply ||Exhaust gas heat exchangers ||Feed system ||Feed extraction pump ||
Flow measurement || Four stroke engines || Fuel injector || Fuel oil system || Fuel oil treatment ||Gearboxes || Governor ||
Marine incinerator ||
Lub oil filters ||
MAN B&W engine ||
Marine condensers ||
Oily water separator ||
Overspeed protection devices ||
Piston & piston rings ||
Crankshaft deflection ||
Marine pumps ||
Various refrigerants ||
Sewage treatment plant ||
Starting air system ||
Steam turbines ||
Steering gear ||
Sulzer engine ||
Turbine gearing ||
Two stroke engines ||
UMS operations ||
Drydocking & major repairs ||
Critical machinery ||
Deck machineries & cargo gears
|| Control and instrumentation
||Engine room safety ||
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