Definition
In order to prevent the water into ships, installed on
the hatch wooden or steel cover, also can be used as supporting structure of
cargo deck, called hatch cover .According to the requirements of general
tightness, divided into water tight hatch cover, oil tight hatch cover and non
tight hatch cover.
Hatch cover main role
is to ensure that waves and rain do not invade the cargo hold, some hatch cover
also bear weight of cargo on deck.
small hatch cover installed in liquid cargo warehouse,
refrigerated cargo
warehouse , personnel access hatch and manhole
According to the transmission mode divided into
rolling hatchcover l, oblique type, sheathed type, roll shift including lateral
displacement type, cascade, roll roll type, hinge type including hinged flap,
folding and so on.
With tightness hatch can devide into watertight,
oiltight, airtight and nontight hatchcover etc., according to the different
tightness that hatch cover plate and the adjacent components are respectively
equipped with layering, packing, gasket, pressing device sealing apparatus.
classification
According
to the hatch size, divided into large and small hatch cover. The former is used
for bulk cargo loading, material or vehicle cargo, cabin hatches; the latter is
used for loading liquid cargo, refrigerated cargo and personnel entrance hatch
and manhole.
According
to hatch cover plate material and type have assembly wooden or metal hatch
cover, Box type hatch made by metal or glass. Small hatch cover generally open
and close by human, large hatch cover must use electric or hydraulic driven
mechanical opening and closing.
According
to the transmission mode can be divided into rolling hatch cover ,verrtical
type, oblique type, sheathed type, roll shift including lateral displacement
type, cascade, roll roll type, hinge type including hinged flap, folding and so
on.
According
to tightness with water tightness, oil tightness,gas tightness and non tight
hatch cover etc., according to the different tightness that hatch cover plate
and adjacent components are respectively equipped with composed of layering,
packing, gasket, pressing device of sealed cabin device or sealing device.
1.Weathertight
cargo hatch cover
Cargo
hatch in the freeboard deck must steel weathertight hatch cover.
2.Oil
sealing cargo hatch cover
Cargo
hatch cover not install in conceal place,should not be less than 600 mm * 600
mm. Measurement hole diameter not less than 150 mm and observation hole hatch.
The hole should ensure effective oil tight cover closing device. The opening of
cargo hatch usually made of round or oval.
3.Non
watertight hatch cover fit cargo and residential
Under
cabin deck hatch without coaming, hatch cover parallel with around.
Hatch design requirements
1.The
structural strength of all open deck hatch cover should be adjacent to around
structure.;
2,
Hatch cover closure device should ensure the weathertight;
3,The
vehicle deck hatch cover if under vehicle load, hatch cover design pressure
should be by vehicle load values of the strength check.
Weathertight hatchcovers installation
inspection
Door,
window,cover are small weathertight closing devic. Because the number much, the
shipyard during installation random checks, include:
1.Look
up Small weathertight hatchcovers marine product certificate, and check the
real stamp or mark.
2.The
opening position according to the approved classification review drawings
inspection cover. Particular attention should be given to the freeboard deck
Small weathertight hatchcovers, for Small weathertight hatchcovers, focus on
examination deck height.
3.The
cover is installed, check the structural integrity, durability and performance
of headstock.
4.The
welding quality check.
5.Check
door ,window, cover tightness. General installation quality pigment adhesion
method check the seal, then after installation, flush test according to the
classification society.
Steel watertight cargo hatch cover
test
Steel
cargo hatch covers is an important hull outfitting equipment, which is used to
hatch cover and protect the cabin and goods from invasion of wind and rain. When
the ship loading and unloading of goods, can be easily opened or closed, the
cargo hatch covers should have enough strength, to ensure under waves or other
set of load not deformation, effect use.
Steel
watertight cargo hatch cover generally with shipyard's quality inspection
department inspection certificate, should accordance with classification
society, apply ship inspection of product ,during manufacturing process to surveyor
and ship owner submit acceptance and inspection of steel watertight cargo hatch
covers. Classification society give certificate to acceptable covers.
Steel
watertight cargo hatch covers installation inspection has two contents: ship
hatch coaming installation inspection; hatch cover at coaming installation inspection
and test.
