Dredge head and method of using the same in which the solids of the interface between the consolidated soil and the water source are released as a slurry into the atmosphere adjacent the swath cut by the dredge head to deposit the solids remote from the swath.

It has now been experimentally determined that the concept of said 
application with respect to the aerial disposal of the excavated material 
has broader application than aquatic growths and unconsolidated matter 
wherein a slurry is jet sprayed having a solids content in the order of 
5-10%. 
By modifying the cutterhead and combining with it means for facilitating 
and controlling the forward movement of the cutter head into the material 
to be excavated, it becomes practical to use the concept of said 
application to dredge consolidated material. For example, it may be used 
to provide navigable channels in upland as well as to deepen waterways 
with relatively consolidated bottoms. 
With adequate power means for providing a substantially continuous 
controlled advance of the cutterhead into the consolidated material to be 
excavated, a slurry having a much higher solids content may be aerially 
handled with all the advantages of said application. 
The cutterhead of my U.S. Pat. No. 3,971,148 issued July 27, 1976, as 
disclosed in said copending application, involved the use of two pairs of 
horizontally aligned and supported augers supported at their outer and 
inner ends in bearing and chain cases. When used to cut a swath, the 
forward faces of the cases presented abutments to the interface between 
the consolidated soil and the water supply used to slurry the excavated 
material. These abutments resist the desired continuous movement along the 
longitudinal axis of the swath being dredged. 
According to the present invention, the box section cutterhead has been 
modified to provide a continuous cutting action at the interface between 
the consolidated soil and the water supply, the full width of swath. In 
one form, forward of each bearing and chain case is a rotated vertical 
shaft upon which is provided soil tilling means which break up and direct 
the soil confronting the cases toward the intake zone. Another form of the 
invention shows the use of high pressure water jets for breaking up the 
consolidated soil forward of abutment structure of the cutterhead 
presented to said interface. 
As illustrated, the cutterhead of said patent is provided with an 
additional set of horizontal augers. Forward of each bearing and chain 
case is a vertical shaft for rotating the tilling members. 
If desired, a suitable rake, rotated about a horizontal axis may be 
associated with the cutterhead as a superstructure disposed forward of the 
cutterhead as disclosed in said copending application. 
In experimental practice of the invention, it has been found advantageous, 
in order to handle slurries having a percentage of solids in excess of 
5-10%, to equip the cutterhead with one or more high pressure water jets 
directed into the intake zone to mitigate cavitation, reduce clogging and 
to dilute the slurry.

In FIGS. 1 and 2, the dredge 10 is shown cutting a swath 35 in upland to 
provide a canal 116 to the open water 114, the nozzles 12 and 14 
depositing the dredged material as a thin cover along both sides of the 
canal 116 with minimum impact upon the environment along the canal. 
As shown, a suitable rotary excavation attachment 118 is located forward 
and above the cutterhead 34, being hydraulically rotated counterclockwise 
to engage and break up the upland. Attachment 118 may take many forms such 
as having a central, horizontally extended shaft 119 carrying a series of 
spiders 120 spaced along the shaft and having shovels or the like mounted 
on the outer ends of the radial arms of the spiders 120. The broken upland 
material is directed into the path of the cutterhead 34 and slurried as it 
is carried into the inlet of the pump 42 to be sprayed by the nozzles 12 
and 14. 
FIG. 3 is a front view of the dredge as shown in FIGS. 1 and 2 with the 
attachment 118 removed and the cutterhead of my U.S. Pat. No. 3,971,148 
modified by adding another set of augers 34', all three sets of augers 
being carried in the bearing and chain cases 34". 
The hull of the dredge 10 may take any suitable form capable of providing 
shallow draft, stability and steerageway under the thrust propelling 
influence of the adjustable jet nozzles 12 and 14. 
At its forward end the hull 20 is forked to provide hull portions 26 and 28 
spaced to receive the two part pivoted boom 30 mounted on the pivot pins 
32. At its forward end, the booms 30 carry a dredge cutterhead 34 having 
an added auger set 34' but otherwise conforming to that shown in said 
patent. Cutterhead 34 produces a box section trench or swath 35 ahead of 
the dredge 10 which is preferably at least slightly wider than the hull 20 
to allow the dredge 10 to follow the cutterhead 34 in all water depths as 
well as when cutting into uplands. 
In FIG. 4, a hydraulically actuated cutterhead shield 36 is shown pivotally 
supported about the axis 38 carried on the cutterhead 34 to provide 
material confinement. A flexible suction line 40 extends between the 
cutterhead 34 and the pump 42 which is preferably equipped with shear 
blades as disclosed in my copending application Ser. No. 221,219 to 
further comminute the solids in the slurry passing the cutterhead 34 to 
reduce clogging of the system to an acceptable operating level. 
Discharge pipe 44 of the pump 42 has a Y-portion 46 to which are connected 
flexible conduits 48 extending to the inlet ends of the adjustable jet 
nozzles 12 and 14. Preferably the nozzles 12 and 14 are located at the 
forward end of the hull 20 and adjacent the cutterhead 34. In practice, 
this location has been found to provide the best steerageway under jet 
reaction propulsion and places the jets in the forward view of the 
operator. 
The support structure for the jet nozzles 12 and 14 may comprise brackets 
50 located at the front corners of the hull 20 to which fixed rigid 
vertical posts 52 are mounted. Rotatable sleeves 52' are carried on the 
posts 52 and rotated relative to the posts 52 by hydraulic cylinders 54 
pivoted to the hull 20 at one end and having rods 56 pivotally connected 
to brackets 58 fixed to the sleeves 52'. A horizontal brace 52" provides 
support for the posts 52 to better carry the reaction of the jet nozzles 
12 and 14 and to assist in transferring this reaction to the hull 20. 
Supporting the nozzles 12 and 14 for oscillation about horizontal axes are 
bearing members 60 fixed to the vertical sleeves 52'. Oscillated members 
60' are supported in the members 60 to which arms 62 are fixed for pivotal 
connection to the rods 64 of the hydraulic cylinders 64'; the lower ends 
of the cylinders 64' being pivoted at 66 to arms 66' fixed to the sleeves 
52'. Brackets 60" fixed to and oscillated with the members 60' are 
attached to the nozzles 12 and 14. 
It has been found in practice that oscillation of the sleeves 52' through 
an arc in the order of 160.degree. and oscillation of the members 62 
through an arc in the order of 105.degree. is adequate for jetting of the 
slurry as well as for moving and steering the dredge 10. However, it will 
be understood that the members 60' may be so adjusted that both nozzles 12 
and 14 may discharge slurry laterally of the same side of the dredge 10 or 
the nozzles 12 and 14 may be adjusted to avoid spraying passing traffic, 
specific areas, etc. along the swath being cut by the cutterhead 34. 
As shown in FIG. 1, the nozzles 12 and 14 are directing the dredge spoils 
to opposite sides of the dredge 10 and the swath being cut by the 
cutterhead 34. The spray pattern 68 of the nozzle 12 being shown similar 
to the pattern 70 of the nozzle 14. 
Referring to FIG. 3, the nozzle 12 is shown equipped with a diffuser 100 
which in its simplest form comprises a threaded rod 102 having a knob 104 
at one end and point 106 at the outer end which on axial adjustment 
intersects the jet stream of the nozzle 12 to alter its spray pattern. 
To fully appreciate the departure of the method and apparatus for spoils 
disposal disclosed herein: all previous methods in commercial use involved 
piping pumped spoils to containment areas creating islands, or casting by 
boombucket to the immediate sides of the excavation creating artificial 
berms and banks alongside of the excavation. The only other alternative 
available was to haul the spoils by barge or ship to deep water or remote 
spot-disposal sites. All of these courses create environmental hazards 
which are presently unacceptable also. Also, such methods are inflexible 
and costly. 
In practice, the method and apparatus of the present invention involves the 
slurrying of spoils ahead of the movement of a pump carrying flotation 
dredge or other means of conveyance; pressurizing the slurry which has 
been prepared for its passage through restrictive nozzles; passing the 
slurry through one or more nozzles to provide air-jetting distance 
capability using controllable diffusion and vertically and horizontally 
controlled nozzles to provide rainlike thin wide disbursement of 
spoil-slurry over large areas; such disbursement alongside the excavation 
being carried out with little, if any, permanent impact upon the 
environment. 
Further, by using the reaction of the air-jetting nozzles 12 and 14 to 
propel and steer the dredge 10 or to at least assist therein plus 
providing disposal of the spoils in a continuous movement free of anchors, 
winching, pipes, etc., great flexibility, speed and cost reductions not 
previously obtainable are being experienced in demonstrations conducted 
under the authority of those agencies regulating the use of public waters 
and wet lands. 
In FIG. 4 is a schematic view partially shown in broken section in which 
water jets 121 are shown directed at the intake 40' of the suction line 
40. The water jets 121 will tend to break up material moving toward the 
intake 40' and reduce any tendency of clogging or cavitation. 
In lieu of the attachment 118 to assist in breaking up the material to be 
dredged, in FIG. 4 the shield 36 is shown equipped with teeth 125 to 
enable the same to function in the manner of a backhoe. 
Referring to FIGS. 5 and 6, the boom 30 carries the cutterhead 34 with the 
cases 34" supporting the three sets of augers 34'. Embracing the boom 30 
and cutterhead 34 is suitable support structure carrying the vertical 
shaft assemblies associated with each case 34". As shown, the support 
structure comprises top horizontal members 146 converging to gussets 148 
at their outer ends to carry the upper bearings 150 for the vertical 
shafts 152. Similar lower members 154 support the lower bearing 156. 
Members 146 and 154 are held in vertical spaced relation by vertical frame 
members 158. Suitable hydraulic motors 160 are connected to the upper ends 
of each shaft 152 to rotate the same in the bearings 150 and 156. 
Each shaft 152 is disposed directly in front of each case 34" and supports 
for rotating vertically spaced tilling members 162 in the form of three 
sided plates 162 having tines or knives 166 located 120.degree. apart. On 
rotation the knives 166 have clearance with the vertical faces of the 
cases 34", the sweep of the knives 166 being at least equal to the width 
of the cases 34" so as to clear the way for the surface of the case 
presented to the material being excavated. To avoid confusion, in FIG. 5 
only a few disc 162 are shown in full line, the remainder are shown 
broken. Spaced supports (not shown) are provided between adjacent plates 
162 and spaced inwardly from the knives 166. 
All of the plates 162 may be the same. However, they are preferably 
arranged on the shaft 152 whereby the knives 166 of adjacent plates 162 
are in spiral offset to reduce the torque on the motor 160 when the 
interface of the consolidated material to be excavated is engaged by the 
knives 166. By arranging the spiral offset in opposite directions from a 
point opposite the intake of the cutterhead, the plates 162 tend to direct 
the spoils toward the intake. A similar effect will be obtained by 
deflecting the knives 166 to provide a pitch effect. 
To clean the knives 166 and to remove material that may be carried by the 
knives 166, cleaner bars or knives 168 are provided in spaced vertical 
arrangement corresponding to the vertical spacing of the members 162. 
Knives 168 are attached at their inner end to a common vertical support 
170 and project into overlapping relation with the knives 166. The motors 
160 are rotated in the directions indicated by the arrows 172. 
In the event that embracing support structure for the vertical shaft 
assemblies which till the consolidated soils at the interface forward of 
the cases 34" presents an abutment to the interface such as the frame 
member 174 of FIG. 8, a row of spaced high pressure water jet nozzles 176 
may be provided in spaced relation and directed toward the interface 
between the consolidated material to be excavacated and the water supply 
of the waterway used to form a slurry. Nozzles 176 are shown mounted on a 
supply pipe 178 attached to the member 174 by the angle rods 180 welded at 
182 to the member 174 and at 184, the rods 180 also acting as guards for 
the nozzles 176. 
In FIG. 9 is shown a modification to perform the same function as the 
vertical shaft assemblies carrying the plates 162 and knives 166. In the 
illustration, the case 34" carries a supply pipe 186 connected to a source 
of high pressure water. Nozzles 188 connected to the pipe 186 direct a 
vertical sheet of water against the interface forward of the case 34" to 
excavate that area of the interface in opposed relation to the forward 
face of the case 34". 
It will be noted from FIG. 6 that the sweep of the knives 166 extends well 
beyond the side faces 190 of the outer cases 34". This assures a flow of 
the water supply to form the slurry around the ends of the cutterhead 34. 
The means for moving the dredge into the interface between the consolidated 
soil and the water supply may take many forms. Aside from jet reaction, 
outboard as well as inboard engines driving propeller may be used. A 
separate craft such as a tugboat may be used to provide controlled 
continuous forward movement along the longitudinal axis of the swatch 
being cut. 
The high pressure water jets 176 and 188 are shown used to excavate limited 
areas of the interface of the consolidated soil. It is anticipated that 
the use of such jets may be enlarged to excavate more of the interface 
even to the exclusion of the auger 34' wherein the cutterhead of the 
dredge would consist only of high pressure water jets presented to the 
interface in the most effective patterns.