Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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INTRODUCTION AND DESCRIPIION OF THE PRIOR ART
The removal of solid material from a fluid, such as in dredging operations, is
the subject of the present disclosure. In particular, the illustrated embodiment shows a
dredger whose cutting and suctioning incorporates a novel fluid interrupter that allows
higher-speed cutting than possible in known systems.
Although dredgers have been operated for centuries, the field for their use is
so vast that new forms continue to be invented and deployed; the area to be dredged,
material composition, distance from shore, depth from surface, and other factors all
influence what form the dredging will take.
As is discussed competently and at some length in other places, notably the
preamble to U.S. patent #4,631,844 (Deal, "Hydraulic Shovel Dredge System," 1986),
dredging is commonly known in three forms: bucket, which takes discrete loads;
suctioning, which takes continuous flow; and hybrid bucket/suction, commonly with the
suctioning intake inside the bucket. Deal also notes that dredgers using rotating
cutterheads are widely used, and their use is limited to certain compositions of bottom
materials due to their being easily damaged.
Since a catalyzed high-speed chopping action on the scale introduced by the
present invention appears unknown in both commercial use and patent documentation,
only a brief listing of previous art will be provided for interest. U.S. patents Deal (cited);
Faldi (3,624, 933; 1971); Quigg et al (4,227,323; 1980); and Gardner, Jr., (3,248, 812;
1966) show various sorts of dredgers with bucket/suction, but no chopping. Mero (U.S. #
3,226,854; 1966) uses a grating to sort the material. CAn~ n patent Fruhling (74,357;
1902) shows suction with low-speed mixing. Finally, CAnA(1i~n patent Vaughan (963,918;
1975) shows a rotary chopper disposed in front of the suction intake; but for reasons that
will be explained below, a high-speed cutter would be inadvisable in such a
configuration.
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The present invention, in brief, addresses and solves two problems: one, that
as the speed of rotary cutting is increased, a whorl or eddy flow is created in the fluid;
this movement counteracts the suctioning. This is a frustrating problem where high-speed
cutting is preferred or required due to heavy material, or where it is desired to increase
the proportion of solid material in the suctioned flow (and hence increase the efficiency
of the dredging as a whole). The present invention places an interrupter, preferentially in
the form of a baffle wall, immediately adjacent and exterior to the cutting path. This
baffle cuts off the fluid whorls and eddies, and allows the suctioning or other transport
mechanisms to continuously take the target material across the cutting path, where it is
chopped, mixed with fluid, and subsequently sucked into the intake.
The second problem is contingent on the first: the cutting means may on
occasion pick up a hard object such as a rock, and fling it outwards; it may happen that
the baffle will be in the path of movement of this object, either as the object is
momentarily between the blades or as flung. Thus damage could result either to the baffle
or the blade; this is addressed by having a removal and return mechanism incorporated
into the baffle. In the preferred embodiment, this is a hinge and spring, so that the baffle
can swing away when struck, and will immediately swing back to interrupt the fluid flow
once more.
An object of the present invention is to provide a method for high-speed cutting and
suctioning of solid material within a fluid, using the elements of: material transport
means; suctioning intake means within the fluid; high-speed rotary cutting means situated
so that the material must traverse the rotary cutting path of the cutting means in order to
be suctioned into the intake; fluid flow interrupter means adjacent and exterior to the
rotary cutting path; pressure-sensitive interrupter removal means; and automaticinterrupter return means. The method comprises the following steps: a) the cutting means
is impelled along the rotary cutting path at high speed; b) the suctioning means sucks
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fluid across the cutting path and into the intake; c) the interrupter prevents fluid eddies
from forming, which would, without such prevention, counteract the suctioning; d) the
transport means brings material across the cutting path, so that it is cut, mixed with fluid,
and suctioned up the intake; and e) if ever the cutting means transports an uncut solid,
such as a hard rock, that protrudes outside the cutting path so as to strike the interrupter,
the interrupter removal means removes the interrupter so no damage occurs to the cutting
means and no damage occurs to the interrupter, and thereafter the interrupter return
means returns the interrupter to its original position.
It is also an object to provide for such a method in which the material may moveacross the cutting path by virtue of transport of the elements other than the material; that
is, the recited elements other than the material may be moved past the material with the
material essentially stationary until it is cut and suctioned. These other elements may be
aff1xed to a dredging bucket and the dredging bucket may have an opening in its direction
of motion for admitting material. The intake may be a substantially vertically oriented
tube with the rotary cutting means rotating below the tube about the longitudinal axis of
the tube; and the fluid interrupter may be a substantially vertical wall adjacent to the
cutting path.
It is also an object to provide for such a method in which the rotary cutting means
comprises 3 or more blades arranged around the circumference of the rotary cutting path,
and in which the gap between blades, and between the blades and the bottom of the
bucket, is smaller than the largest dimension desired in the material to be sucked into the
intake. The pressure-sensitive interrupter removal means may be a hinge and pin, and the
automatic interrupter return means may be a spring.
It is also an object of the present invention to disclose, in an under~,vater dredging
bucket with an open front to admit material, an apparatus for high-speed cutting and
suctioning of such material; with the apparatus comprising: a suctioning intake tube
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opening into the bucket; rotary impeller means con~i~ting in a substantially vertical
rotating tube that communicates with the intake tube; blade retainer means affixed to the
impeller means; blades releasably affixed to the blade retainer means, with the blades
arranged to follow a rotary cutting path about the substantially vertical longitudinal axis
of the impeller tube; a substantially vertical baffle wall, exterior to and immediately
adjacent to the circumference of the cutting path, with this baffle wall standing so that its
large flat faces radiate from the circumference; substantially vertical pin and hinge means
at the edge of the wall distant from the circumference, so that the edge of the wall near
the circumference may pivot horizontally away from the circumference; and springmeans affixed to the pin and hinge means, with this spring means fashioned so that the
wall returns after pivoting. Using this apparatus, high-speed cutting and suctioning of
dredged material occurs by virtue of the baffle wall improvement, since without the wall
the high-speed blades induce water eddies that inhibit the suctioning of dredged material
past the blades; and using this apparatus, also, hard materials wedged between the blades
so as to strike the baffle wall do no damage by virtue of the pin and hinge means that
pivots the wall allowing the hard material to be thrown, after which the spring means
returns the wall to its previous position. The bottom of the bucket may have a replaceable
digging edge along its front. And the bucket may further comprise: an adjustable height
assembly capable of raising and lowering the front of the bucket; a removable bottom
plate to admit material; and a removable rear plate to allow soft material to flow through
the bucket.
DETAILED DESCRIPTION OF THE INVENTION
For this description, refer to the following diagrams, wherein like numerals
refer to like parts:
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Figure 1, an embodiment of the invented baffle system, partial cutaway,
perspective view;
Figure 2A, prior art system without baffle; partial schematic top view;
Figure 2B, the system of Figure 2A, but with invented baffle; partial
schematic top view;
Figure 2C, the invented system of Figure 2B, with rock and baffle
movement; partial schematic top view;
Figure 2D, the invented system of Figure 2C, one moment later with
rock thrown and baffle returned; partial schematic top view; and
Figure 3, an alternative view of the embodiment of Figure 1, partial
cutaway, side view.
An embodiment of the invention is illustrated in Figure 1, where cutaway of
dredger generally indicated as 10 shows ghosted internal pump 12, ghosted intake tube
14, impeller 16, blade retainer 18, blades 20, baffle 22, hinge 24, and spring 26. Note that
intake tube 14 effectively extends through impeller 16 and blade retainer 18, both of
which have hollow cylindrical centers such as bounded by cylindrical surface 16a inside
impeller 16, so that the effective lower opening of intake tube 14 is at the level of the
bottom lip 18a of blade retainer 18.
Operation of the invented system is as follows:
As dredger 10 is moved in direction of arrow D, dredged material 30 follows
path of arrow M1 towards the blades 20 where it is cut and so mixed with water and the
resultant is sucked up past lip 18a and into intake tube 14. (The pump to provide power
may be pump 12 shown ghosted or a distant pump outside the dredger 10). Since the
blades 20 are moving at high speed along cutting path indicated by arrow B, water
adjacent to and exterior to the cutting path B will be induced to rotate also, along a path
such as indicated by arrow W.
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If allowed to move unobstructed, the water indicated by arrow W would have
the effect shown in Figure 2A (prior art) where the movement of water along path W
interferes with the movement of dredged material 30, which now merely rotates along
path Mo and does not even reach blades 20, much less be sucked up through impeller 16
into intake tube 14 (which is not visible in Figure 2A). Accordingly, in the invention,
baffle 22 (which is in all Figures except 2A) is placed to obstruct path W. As can be seen
in Figures 1 and 2B especially, this results in dispersed motion of water along paths such
as I. As this occurs the amount of water following path W is reduced so that dredged
material 30 can follow path M 1 and be cut by blades 20 and sucked up through impeller
16.
An attendant problem is that on occasion a hard piece of material such as a
rock will be momentarily picked up when it is just the right diameter to fit between two
blades. Figure 2C shows this, where rock 34 is striking baffle 22; it has just been picked
up between blades 20a and 20b. But due to hinge 24, baffle 22 swings out of the way
with harm to neither blades 20 nor baffle 22. Then as shown in Figure 2D, by virtue of
spring 26 baffle 22 returns immediately to re-obstruct water which is gaining momentum
along path W. Rock 34 is thrown aside. Spacing between the blades 20a and 20b, and in
general all blades 20 in this and other unillustrated embodiments, is chosen to prevent
objects from passing between blades 20 that would be too large to pass up through
impeller 16 and up intake tube 14 (shown on Figure 1).
Other configurations are possible and the illustrations herein are only for
example. For instance, there could be more blades or the blades could be of different
sizes or shapes. The spring mechanism is known art and could be otherwise than
indicated, or could be rendered by some electric, electronic, or other form of movement
mechanism without a spring. Other minor variations within the scope of the invention
will be apparent to those skilled in the art.
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Figure 3 shows elements of dredger 10 which have been omitted from earlier
Figures for clarity of explanation of the invented system. An adjustable ski assembly
indicated generally as 40 shows pin 42 in leg 44, allowing adjustable height of digging
edge 45 by lifing front portion of bucket 46 (Digging edge 45 is shown also in Figure
2B). Thus bucket 46 and digging edge 45 can be lowered for digging hard material, such
as gravel and sand, and raised to prevent the bucket 46 from digging the bottom of ponds,
such as sewage ponds for town sewage disposal. This permits the removal the sludge and
mud from such ponds without removing the clay bottom, which has often been installed
to prevent the ponds from leaking. (These raised and lowered positions and ponds are not
diagrammed).
Also shown in Figure 3 are bolts 50 passing through blade retainer 18, as an
example of ways that blades 20 can be affixed; these bolts 50 also pass through the blades
20 and the impeller 16, although this is not visible on the diagrams. In the embodiment
shown in Figures 1 and 3, blades 20 sit in pockets in blade retainer 18, such as ghosted
pocket 52 shown on Figure 1. Thus blades 20 can be easily removed with a single bolt 50
for replacement. Two bolts 50 can optionally be used per blade 20 in situations where
larger blades are used (this two-bolt option is not illustrated).
Also shown (ghosted) on Figure 3 is removable back door 60 which can be
installed to prevent soft material (not illustrated) from passing through the bucket 46.
Removable bottom plate 62, shown ghosted on Figure 3 and in solid in Figure 2B, can be
removed if it is desired to have soft material from the bottom (not shown) having direct
access to blades 20. With both door 60 and plate 62 in place as shown in the Figure 3,
back door 60 can function as a dragline bucket. And digging edge 45 (shown ghosted in
Figure 3) is replaceable, which is important since in situations with hard bottom material
(not shown) it will receive rough treatment.
The foregoing is by example only, and the scope of the invention should be
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limited only by the appended claims.
