Page 309 - Ship Construction.DJ Eyres 6Ed

Ch26-H8070.fm Page 298 Wednesday, October 18, 2006 7:01 AM

26
Pumping and Piping Arrangements

--- ใช้เพื่อการศึกษาเท่านั้น---

In the construction of a merchant ship the shipbuilder is concerned with the
งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี
installation of the statutory bilge drainage, ballasting, general services, and
where required the liquid cargo loading and discharging, pumping and
piping arrangements. Arrangements may also be fitted in tankers for tank
washing and for introducing inert gas into the tanks.

Bilge and Ballast Pumping and Piping

All cargo ships are provided with pumping and piping arrangements so that
any watertight compartment or watertight section of a compartment can be
ึ
pumped out when the vessel has a list of up to 5°, and is on an even keel. In
the case of passenger ships, each compartment or section of a compartment
may be pumped out following a casualty under all practical conditions
whether the ship is listed or not.
The arrangements in the machinery space are such that this space may be
pumped out through two suctions under the above conditions. One suction
is from the main bilge line and the other from an independent power driven
pump. An emergency bilge suction is also provided in machinery spaces,
and may be connected to the main circulating water pump (for condenser)
in steam ships, or the main cooling water pump in motor ships.

BILGE SUCTIONS As the vessel is to be pumped out when listed it is nec-
essary to fit port and starboard suctions in other than very narrow spaces.
Generally vessels are designed to have a moderate trim by the stern in ser-
vice, and the suctions will therefore be placed in the after part of the com-
partment. However, where a ship has a single hold which exceeds 33.5 m in
length suctions are also arranged in the forward half length of the hold. On
many vessels a sloping margin plate is fitted and a natural bilge is formed
with the suctions conveniently located within this recess. Adequate drainage
to the bilge is provided where a ceiling covers this space. If however the
tank top extends to the ship sides, bilge wells having a capacity of at least
3
0.17 m , may be arranged in the wings of the compartment. In a passenger
ship these bilge wells must not extend to within 460 mm of the bottom shell
so as to retain a reasonable margin of safety where the inner bottom height