A Treatise On The Principles And Practice Of Dock Engineering
Forfatter: Brysson Cunningham
År: 1904
Forlag: Charles Griffin & Company
Sted: London
Sider: 784
UDK: Vandbygningssamlingen 340.18
With 34 Folding-Plates and 468 Illustrations in the Text
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SUCTION DREDGERS.
91
should not be overlooked, however, that this arrangement, whilst extremely
effective for its particular purpose, somewhat reduces the useful capacity
of the hopper for solid material, by adding to the gross load carried.
The suction pump dredger would also be applicable to silt and mud, were
it not that the lower spécifie gravity of such material renders it practically
impossible to secure its deposition within the limits of the receiving hopper.
Silt will take nearly as many hours to settle as sand takes minutes. It is
sometimes, however, an advantage to bring a suction pump to bear on mud
in situations otherwise inaccessible, such as gate platforms and recesses.
The mud thus disturbed settles in more open positions, where it can
conveniently be removed by other appliances. The discharge of the muddy
effluent of a suction pump into a tidal or other current is a simple but
efficacious means of maintaining a waterway, provided that the deposit be
light and the current sufficiently powerful to retain it in suspension until
it reaches a place where its settlement will do no harm.
Suction pumps possess very great advantages in exposed situations, where
the incessant motion of the waves materially interferes with the working
of other forms of dredging apparatus. Equipped with telescopic pipes and
flexible joints, they can adjust themselves to the rise and fall of the
vessel and be quite independent of variations of level, either momentary or
prolonged. The manifest convenience and safety attaching to dredgers of
this class has led to repeated attempts to adapt them to the removal of
material other than sand. With this object in view the lower end of the
suction pipes has been fitted with a number of cutting blades, the revolu-
tion of which, by suitable gearing, is intended to disintegrate clay, marl, and
other compact material to such a degree as will admit of their being drawn
up the suction pipe.
This is the basis of the Bates, the von Schmidt, and other systems
of dredger. The cutters, generally speaking, are cylindrical, hollow,