Note: Descriptions are shown in the official language in which they were submitted.
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Background of the Invention
(1) Field of the Invention:
The present invention relates to an ice-breaking a~paratus
for facilitating navigation of ships or barges in icy waters.
(2) Brief Description of the Prior Art:
Icebreakers or iceboats have been generally used as vessels
navigating in icy waters. In vessels of this type, the kinetic
energ~ of the vessel is utilized for breaking ice and in order to
obtain a high ice-breaking capacity, therefore, it is necessary
to increase the kinetic energy by enlarging the hull or enhancing
the power of the main engine, and it also is necessary to improve
the structure and shape of the hull per se so that the kinetic
energy can be transmitted effectively at high efficiency to the
ice to be broken. Accordingly, attempts have heretofore been
made to attain improvements in the foregoing points. In practice,
however, in building ships or vessels of this type, various
economic and other limitations are imposed on increasing the
dimensions of the hull or powering-up of the engine, and therefore,
no satisfactory ice-breaking capacity can be obtained in many
cases.
In general, the ice-breaking operation is divided in two
types, namely, continuous ice breaking applied to relatively thin
ice and charging ice-breaking applied to thick ice. Continuous
ice breaking is performed by the thrust of a ship and a knife
edge mounted on the bow. Charging ice-breaking is performed by
repeating an approach run from a certain distance and a colliding
against the ice.
These conventional ice-breaking methods, however, are very
inefficient. For example, in the case of continuous ice breaking,
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the forward speed of the vessel is ordinarily lowered by several
knots, although the speed varies to some extent depending on the
thickness of the ice or the capacity of the ship, and in the case
of charging ice breaking, the opening distance by one charging
operation is only from several to several hundred meters.
Accordingly, the ice-breaking efficiency is low, especially in
the case of charging ice-breaking, and further, there is always
the risk involved that during the ice-breaking operation, the
ship will be blocked by ice and will not be allowed to escape.
Obiects of the Invention
The present invention i8 to eliminate the foregoing defects
involved in conventional continuous ice breaking and charging
ice breaking by icebreakers or iceboats.
It is therefore a primary objective of the present invention
to increase the efficiency of continuous ice breaking or charging
ice bxeaking in icebreakers or iceboats navigating in ice waters
and barges (inclusive of pushers and tugboats) for operation in
ice waters without increasing the dimensions of the vessel or
the powers of the main engines thereof.
Another objective of the present invention is to moderate the
dangers involved in charging ice breaking and to ensure efficient
and safe navigation.
Other objects and advantages of the present invention will
become apparent from the following detailed description.
Brief Summary of the Invention
In accordance with the present invention, the foregoing
objects can be attained by an ice-breaking apparatus for ships
and barges for operation in icy waters, including nozzles for
jetting high pressure fluid to the ice to break the ice, wherein
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a rotatable turret is mounted on the bow and nozzles are disposed
on an extensible arm attached to said turret, or nozzles are dis-
posed on the bow portion, either independent of or in combination
with said nozzles disposed on the extensible arm.
According to the present invention, cracks or grooves are
formed in the ice by the action of high pressure fluid, for
example, high pressure water, jetted from the above-mentioned
nozzles, whereby the kinetic energy need not be especially
increased. Further, since ice is broken only at necessary parts
or portions thereof, the operation efficiency can be remarkably
enhanced. Moreover, since the hull intrudes into broken or
cracked ice, damages to the hull by the ice-breaking operation
can be effectively prevented from occurring, and in case of
charging ice-breaking, the foregoing risk of stalling in ice can -~
be eliminated.
Brief DescriPtion of the Drawinq
Figure 1 is a plan view, showing the state where a vessel
for operation in icy waters breaks ice;
Figure 2 is a side view of the bow structure equipped with
ice-breaking nozzles according to the present invention, which
illustrates an embodiment in which ice is thrust down in the water
and broken;
Figure 3 i5 a side view of the bow structure equipped with
ice-breaking nozzles of the present invention, which illustrates
an embodiment in which ice is raised up from below and broken:
Figure 4 is a side view of the bow structure equipped with
ice-breaking nozzles of the present invention, which illustrates
an embodiment in which the nozzles are disposed on an extensible
arm on a turret; and
z~
Figure 5 is a diagram illustrating in detail a head structure
and a high pressure water pipe system in the apparatus of the
present invention.
Detailed DescriPtion of Preferred Embodiments
Figure 1 illustrates the state where ice is broken according
to the customary continuous ice-breaking method. As is seen
from Fig. 1, a vessel is allowed to advance through the generation
and development of cracks in an ice floe and through the breakage
of the ice floe. Accordingly, if a state promoting breakage of
an ice floe is artifically realized in advance or conditions ~or
bringing about this state with ease are produced, it will be
possible to perform the ice-breaking operation more readily and
easily than in the conventional methods.
As a means for generating cracks in ice floes, as pointed out
hereinbefore, there has been used a knife edge mounted on the bow.
In the present invention, an ice-breaking nozzle for jetting high
pressure fluid is used instead of said conventional knife edge.
One of the characteristic features of the present invention
resides in the use of such a nozzle.
This ice-breaking nozzle may be disposed directly on the bow
or it may be supported on an extensible arm mounted on a turret
device disposed on the hull. Tn principle, the present invention
includes these two features as main embodiments.
The present invention will now be described in greater detail
in conjunction with the accompanying drawings.
Referring to Fig. 2 illustrating the structure of the bow
portion 2 where a number of nozzles 1 are arranged, the nozzles 1
are embedded in the bottom portion of a groove 3 formed on the
bow 2 so that damage to the nozzles by direct contact or collision
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with the ice can be prevented.
High pressure fluid, for example, sea water or fresh water
stored in the ship, which has been pressurized, is jetted from
these nozzles, whereby cracks become formed in the ice. Accord-
ingly, the ice-breaking efficiency is enhanced and the sailing
speed is increased. In case of charging ice-breaking, if CUt5
are formed by the first charging, the ice is readily broken by
the second charging, and hence, the ice-breaking capacity can be
remarkably enhanced.
In the embodiment shown in Fig. 2, ice is thrust down by the
bow portion and thus broken. On the other hand, in the embodi-
ment shown in Fig. 3, ice i8 raised up from below and thus broken.
Specifically, in the embodiment illustrated in Fig. 2, nozzles
are arranged so that cracks are generated from the upper portion
of ice 4 and in the embodiment shown in Fig. 3, nozzles are
arranged so that cracks are generated from the lower portion of
ice 4.
When nozzles are disposed in the bow portion aq shown in
Figs. 2 and 3, in order to maintain an optimum distance between
each nozzle l and ice 4 and to prevent damage to the nozzles at
the time of collision, the nozzles are disposed at a position
inner to the position of the shell plating in the bow portion,
and they are surrounded by electrically heated panels. As a means
for maintaining a certain distance between the nozzles 1 and ice
4, in the embodiments shown in Figs. 2 and 3, a groove 3 is
formed. Alternatively, an optimum distance can be maintained by
depressing only parts of the bow near the noæzles 1.
Figure 4 illustrates an embodiment in which a movable type
ice-breaking apparatus is mounted on a vessel. In Fig. 4,
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reference numeral 2 represents the bow portion of an icebreaker
or iceboat or barge. A rotatable turret 5 is disposed on the
deck, and an extensible arm 6, the length of which can be adjusted,
is mounted on this turret 5. On the top end portion of the arm
6, there is arranged a hydraulic device 7 for adjusting the
vertical position of nozzles, and another hydraulic device 8 for
adjusting the nozzle angle, and a head 10 is attached through a -
damper 9. The top end of the arm 6 is connected to a hydraulic
winch through a wire 11. By this winch, the load of the arm and
other members is supported, and this winch is operated when a
large displacement is required for the head 10.
In the structure shown in Fig. 4, optimum conditions for the
ice-breaking nozzles can be optionally selected. More specifically
the distance from the bow, the distance from the ice surface, the
cutting angle and other conditions can be appropriately set by
operating the extensible arm 6 as required. Further a distance
measuring device including an ultrasonic wave generator and an
ultrasonic w~ve receiver is disposed in the vicinity of the nozzles
and the nozzles are automatically controlled so that they are
located at optimum positions from the ice surface irrespective
of the convex-concave state of the ice surface and the change of
posture of the vessel.
When the ice-breaking apparatus of the present invention is
used for continuous ice breaking, breaking of ice in a direction
facilitating the advance of the ship is effectively attained or
promoted, and the sailing speed can be made much higher than in
the case where the ice-breaking apparatus of the present invention
is not usedO In case of charging ice-breaking, if the ship is
stopped at the ice-breaking point and ice is cut or cracked in
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advance by using the ice-breaking apparatus of the present inven-
tion, an easily broken state is brought about in the ice, and as
compared with the case where the ice-breaking apparatus of the
present invention is not used, the critical ice-breaking capacity
can be remarkably enhanced.
Figure 5 illustrates a head structure and a high pressure
water (or sea water) pipe system. Sea water or fresh water in a
sea chest or water tank 12 is sucked by a booster pump 13 and
passed through a heat exchanger 14 and a filter 15, and the
pressure is further elevated by a piston pump 16. A thermometer
17 is disposed bet~een the heat exchanger and the filter, and the
piston pump is driven by an electric motor 18. Pressurized water
from the piston pump is introduced to the head through a nozzle
line 19. A by-pass valve 20 is disposed midway in this line to
discharge high pressure water in case of emergency. The head
includes a type (a) and a type (b). The head (a) is a moving
type head. A skirt 21 is attached to prevent the head from being
damaged at the time of collision, and in the interior, there are
disposed a nozzle 22 and an echo distance measuring device 23.
ThiS echo distance measuring device is connected to the interior
of the ship through power and signal cables 24. The nozzle is
heated by an electrically heated panel 25 so as to prevent freezing
of the liquid in the nozzle. For the same reason, a nichrome wire
26 is aligned along the nozzle line.
The head (b) is one to be disposed in the bow structure.
High pressure water supplied through a nozzle line 19 is distri-
buted by a control valve 28, passed through a heated pipe 26 and
introduced to a designated nozzle 22. The nozzles 22 are arranged
on the bottom face of a slit 3 formed on the shell plating 29 of
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the bow in a state surrounded by an electrically heated panel 25,
In the present invention, an ice floe is broken or breaking
of an ice floe is promoted by an impinging force or cavitation
caused by the jetting of high pressure fluid, and since grooves
or cracks promoting breakage of the ice floe can be formed on the
ice floe effectively by such impinging force or cavitation, the
energy required for breakage of ice can be remarkably reduced
according to the present invention.
As will be apparent from the foregoing illustration, according
to the present invention, prior to breakage of an ice floe,
grooves or cracks are formed on the ice floe, and therefore,
breakage of the ice floe can be remarkably facilitated and the
ice-breaking capacity of a ship or barge can be enhanced. More-
over, dangers involved in the ice-breaking operation can be
drastically diminished and safe and efficient navigation can be
ensured. Accordingly, the present invention makes great and
valuable contribution to the art.
