5
4.
INSTALLATION
Unsafe operation
Improper installation or installation performed by
incompetent or unqualified personnel may result
in unsafe operation, defects and accelerated
corrosion.
Ø
Installation of the box cooler shall only be
carried out by suitably trained, qualified and
instructed engineers, welders and
electricians.
The installation of the box cooler consists of the following
steps:
1.
Designing and preparing the sea chest.
2.
The welding of the mounting frame
3.
Installation of the tube bundle and the water cover
4.
Preparation and installation of the piping system,
including the selection and installation of safety
devices to prevent overpressure and overheating.
5.
Electrical installation of the (optional) ICAF system.
4.1.
SEA CHEST DESIGN
The box cooler may be arranged in either athwartship or
longitudinal position:
1.
Transversely (athwartships)
: this is the most common
way to mount a box cooler. The box cooler is mounted
between the existing frames of the vessel (see fig. 3a).
2.
Longitudinally (parallel with fore and aft centerline)
:
this method is less popular as the frames have to be
cut open to allow the special sea chest to be installed
(see fig. 3b).
3.
Ensure that the top plate of the sea chest is on or
below the waterline when the ship is empty. This is to
make sure that the tube bundle is fully surrounded by
(sea) water at all times.
4.
Ensure adequate ventilation of the sea chest to
prevent that air is trapped inside the sea chest which
reduces the heat transfer. Suggested is to weld a thick
walled pipe into the top plate with a minimum inside
diameter of 70 mm.
5.
Maintain a minimum free space of 80 mm between
tube bundle and any part of the ship's construction for
a coated box cooler and 100mm for an uncoated box
cooler.
Figure 3a. Transverse mounting.
Figure 3b. Longitudinal mounting.
6.
The seawater inlet slots are to be situated in the base
of the sea chest and positioned transversely
(athwartships).
7.
The seawater outlet slots are to be situated in the
outer wall of the hull and positioned longitudinally
(parallel with fore and aft centerline) directly under
the top surface of the sea chest, but must remain
below the waterline when the vessel is empty.
8.
The number of slots is dependant upon various factors
such as speed, service, shape, etc.
The width of each opening is 50 mm but the length
depends on the frame spacing of the ship. A typical
slot opening in a hull is 50 x 400 mm = 20,000 mm
2
or
2 dm²
.
