JP7319946B2 - Dredging equipment, dredging system, and dredging method - Google Patents

Description

The present invention relates to a dredging device, a dredging system, and a dredging method.

In a reservoir such as a dam lake, sediment that has flowed in with rainwater, river water, or the like accumulates on the bottom of the lake. Therefore, in dam lakes and the like, sediment (sediment) deposited on the bottom of the lake is removed by various methods.
Methods for removing this sediment include land excavation and dredging. Onshore drilling requires dam operation restrictions because it is necessary to lower the water level of the reservoir when excavating the sediment. In addition, there is a problem that the excavation area is limited to the upstream area of the reservoir.
On the other hand, methods of dredging from the water include grab dredging and pump dredging. Sediment deposited on the lake bottom generally contains foreign matter such as boulders, driftwood, fallen wood, and debris. There is a risk that sediment removal efficiency will be significantly reduced due to unavoidable maintenance to remove the sediment. Therefore, although it is preferable to separate sediment from foreign matter as a pre-process in dredging using a pump, it is practically impossible to separate sediment from foreign matter in water.

Here, when the excavated earth excavated from the bottom of the water by the excavating means is discharged, it is possible to prevent foreign matter such as branches and stones contained in the excavated earth and sand from clogging the earth discharging means, A dredging device capable of efficiently dredging earth and sand has been proposed. Specifically, a cutter that excavates the earth and sand on the bottom of the water, a cylindrical body part provided above the cutter, a chamber formed between the cutter and a partition that closes the bottom part of the cylindrical body part, This dredging device includes an earth discharge means for discharging excavated earth and sand taken into a chamber through an opening provided in a cutter by a sand pump (see, for example, Patent Document 1).

JP 2006-214263 A

According to the dredging device described in Patent Document 1, when the sediment deposited on the bottom of a lake is dredged by a pump, there is a problem that foreign substances such as boulders, driftwood, fallen wood, and dust that may exist in the sediment clog the pump and piping. can be resolved.
By the way, as a cause of clogging of a pump or piping, in addition to the above-described foreign matter, a high concentration of sediment in the sucked muddy water can be mentioned. In order to prevent the suction of muddy water with high sediment concentration, a method of adjusting the amount of sucked muddy water by the pump by operating, or providing a collar at the tip rotation part of the dredging attachment to prevent the dredging attachment from penetrating into the sediment One way is to limit the amount. However, the operating method results in intermittent sediment suction, and the method of limiting the amount of penetration of the dredging attachment into the sediment limits the pumping capacity. there is a risk of Moreover, when applying dredging attachments in dredging at great depths, the reduction in dredging efficiency can be even more pronounced with the operating method.
Therefore, a dredging device, a dredging system, and a dredging method that can eliminate clogging of pumps and pipes due to foreign matter that may be present in sedimentation, as well as clogging of pumps and pipes due to, for example, muddy water with a high sediment concentration. development is desired.

An object of the present invention is to provide a dredging device, a dredging system, and a dredging method that can achieve efficient dredging without clogging the pump or piping when dredging sediment using a pump. there is

In order to achieve the above object, one aspect of the dredging device according to the present invention is
an underwater working machine having a dredging attachment attached to the tip of an arm;
a controller;
The dredging attachment includes:
a pump;
a suction tube and a transport tube communicating with the pump;
a screen surrounding the suction port of the suction tube and having a plurality of openings and cutting bits;
an actuator that rotates the screen;
It is characterized in that the controller executes change control of the rotation speed of the actuator.

According to this aspect, according to the change control of the rotation speed of the actuator, the change control of the rotation speed of the screen surrounding the suction port of the suction pipe is executed, for example, by reducing the rotation speed of the screen, the sediment concentration is reduced. It can be lowered to suppress piping clogging. This effect is that while the amount of suction by the pump is constant, the rotation speed of the screen decreases, the amount of sand that is cut is reduced, and the amount of sand that is sucked into the suction pipe through the opening is reduced. This is because the sediment concentration decreases. Therefore, the sediment concentration and the amount of sediment (sediment flow rate) are measured in the suction pipe and the transport pipe, and if the sediment concentration is too high based on the measurement results, change control is executed to reduce the rotation speed of the actuator. Thus, it is possible to suppress clogging of the suction pipe, the transport pipe, and the pump.
In addition, since a screen with a plurality of openings is arranged so as to surround the suction port of the suction pipe, it is difficult for foreign matter such as boulders, driftwood, fallen wood, and dust to be taken into the screen, and suction is performed. Clogging of pipes and pumps by these foreign substances is also eliminated.
Furthermore, since the screen equipped with cutting bits is rotated by the actuator, when foreign matter approaches the opening of the screen due to the suction force of the pump, the cutting bits can repel or crush the foreign matter. The blockage prevention effect of the suction tube or the like is further enhanced.

Underwater working machines constituting the dredging apparatus of this aspect include working machines that travel on the bottom of a lake, working machines that ascend and descend along a shaft suspended from a barge, working machines that are suspended from a barge by wires, and the like. , and various types of underwater working machines.
Further, the "sediment concentration" is, for example, the volumetric sediment concentration obtained from the volume of the soil particle portion of the sediment and the volume of the water containing the sediment (muddy water). Regarding the concentration of sediment that clogs pumps and suction pipes, prior to implementation work, conduct test construction using pumps and suction pipes that are actually applied, and specify in advance the concentration of sediment that can clog pumps and suction pipes. , it is desirable to specify the dimensions of the water inlet that can be adjusted to less than this sediment concentration. For example, if the sediment concentration that blocks the suction pipe etc. is specified as about 20% by this test construction, the target sediment concentration is set to about 15% or 10%, and water is supplied so as to satisfy this target sediment concentration. The size of the mouth (aperture) can be set. In addition, it is preferable to set the diameter of the suction pipe, the opening of the screen (screen opening), etc., in consideration of the suction efficiency of the dredged sand, the non-blocking property of foreign matter, and the like.

In another aspect of the dredging device according to the present invention, at least one of a sand lifting flowmeter, a sediment concentration meter, and a pressure gauge is attached to the suction pipe and the transport pipe,
A load ammeter is attached to the pump,
The controller has a receiving unit, a storage unit, a comparison calculation unit, and a control unit,
The receiving unit receives measurement data measured by at least one of the sand lifting flowmeter, the sediment concentration meter, the pressure gauge and the load current meter,
The storage unit stores at least one of a sand discharge flow rate threshold, a sediment concentration threshold, a pressure threshold, a dredging amount threshold specified by the sediment discharge flow rate and the sediment concentration, and a load current threshold,
The comparison calculation unit compares the measurement data with a threshold associated with the measurement data,
It is characterized in that, when the measured data exceeds the related threshold value, the controller executes control to reduce the rotation speed of the actuator.

According to this aspect, in at least one of the suction pipe and the transport pipe, the sediment pumping flow rate, the sediment concentration, and the pressure are measured, or the load current is measured in the pump, and any of the measured data and preset for them By executing control to reduce the number of rotations of the actuator by comparing with the set threshold value, blockage of the suction tube or the like can be suppressed based on various indices. In addition, either or both of the suction pipe and the transport pipe are equipped with a sediment flow meter, a sediment concentration meter, and a pressure gauge. , and all the measurement data are stored in the storage unit, and the dredging amount specified by the sediment discharge flow rate threshold, sediment concentration threshold, pressure threshold, sediment discharge flow rate, and sediment concentration stored in the storage unit may be compared with the dredging volume threshold and the load current threshold. In this case, if even one element exceeds the threshold, control may be performed to reduce the rotation speed of the actuator (safe side control). may be executed (dangerous side control), and there are various forms of controlling the rotation speed of the actuator using a plurality of measurement data.

Also, in another aspect of the dredging device according to the present invention, the screen
a plurality of vertically spaced annular cross members;
a plurality of U-shaped vertical members spaced apart in the circumferential direction of the plurality of annular horizontal members and connected to each of the annular horizontal members; A plurality of the openings are formed by intersecting the plurality of longitudinal members in a grid pattern,
An inclined plate having a lower end inclined in the rotation direction of the screen is connected to the plurality of annular horizontal members, and a plurality of cutting bits are attached to the front end surface of the inclined plate in the rotation direction of the screen. cage,
The plane view of the screen is circular, and in the plan view of the screen, the front end surface of the inclined plate in the rotational direction is positioned radially outward from the tangential direction of the circle.

According to this aspect, an inclined plate having a lower end inclined in the rotation direction of the screen is provided, and in a plan view of the screen, the front end surface of the inclined plate in the rotation direction (the end surface to which the plurality of cutting bits are attached) is circular. (inclined at a rake angle θ to the tangential direction) creates a dredge with excellent cutting performance.

Further, in another aspect of the dredging device according to the present invention, the dredging attachment further includes a water supply port at a midway position of the suction pipe,
By the operation of the pump, the dredged soil is taken into the suction pipe through the opening of the screen, and fresh water is taken into the suction pipe through the water supply port. It is characterized by being sucked into the pump through a suction pipe and transported through the transport pipe.

According to this aspect, since the water supply port is provided in the middle position of the suction pipe, when the pump is operated, the dredged soil is taken into the suction pipe through the opening of the screen, and the water supply port Fresh water is taken into the suction pipe, and both the fresh water and the dredged sand are sucked into the pump through the suction pipe, so that the fresh water can reduce the concentration of the dredged sand in the sucked muddy water. As a result, clogging of pumps and pipes due to muddy water with a high sediment concentration can be eliminated.
Also, a suitable length of water supply pipe may be attached to the water supply port. In addition, the suction pipe can be a straight pipe or a unit pipe consisting of a straight pipe and a vent pipe. It is desirable to be set at (a position away from the suction port). Furthermore, fresh water supplied to the suction pipe through the water supply port includes tap water, rain water, and purified water supplied from the ground in addition to lake water.

In another aspect of the dredging device according to the present invention, the suction tube is a double tube having an outer tube and an inner tube,
Fresh water supplied to the suction pipe through the water supply port flows through the outer flow path between the outer pipe and the inner pipe, turns around the suction port of the inner pipe, and flows inside the inner pipe. It is characterized in that it is introduced into the channel and sucked by the pump together with the dredged material taken into the inner channel.

According to this aspect, the fresh water supplied through the water supply port flows through the outer channel of the suction pipe made up of a double pipe toward the suction port side, goes around the suction port of the inner pipe, and enters the inside of the inner pipe. By being introduced into the flow path, both the dredged soil and fresh water can be sucked from the suction port of the inner pipe, and the soil concentration of the dredged soil by the fresh water can be reduced more effectively. If the suction pipe consists of a single pipe, it is not possible to reduce the sediment concentration with fresh water in the process from the suction port of the suction pipe to the water supply port of fresh water. This is because it is possible to reduce the sediment concentration with fresh water from the suction port of the pipe.

Here, it is desirable that the suction port of the inner tube is positioned downstream in the suction direction from the suction port of the outer tube. According to this aspect, since the suction port of the inner tube is located downstream in the suction direction of the suction port of the outer tube, fresh water flows through the outer channel of the double tube suction tube, When it goes around the suction port of the pipe and is introduced into the inner channel inside the inner pipe, it suppresses the fresh water that flows out without being introduced into the inner channel, effectively introducing fresh water into the inner channel. can do. "Downstream in the suction direction" means the side of the pump where the suction tube is attached. In addition, the level difference between the suction port of the outer tube and the suction port of the inner tube (the distance from the suction port of the outer tube to the suction port of the inner tube that enters inside) depends on the actually applied pump and the double tube. It is desirable to perform a test installation using a suction tube to determine the level difference that effectively introduces fresh water into the inner channel.

Moreover, it is preferable that a blocking member for blocking the circulation of fresh water in the outer flow path is provided at a position on the downstream side in the suction direction of the water supply port in the outer flow path. According to this aspect, since the shielding member is provided at a position downstream in the suction direction of the water supply port in the outer flow path, part of the fresh water supplied to the outer flow path through the water supply port is It is possible to solve the problem of flowing to the side opposite to the suction port side of the tube and not being introduced into the inner channel. For example, in a suction pipe consisting of a double pipe formed of two steel pipes with different diameters, it is possible to apply a donut-shaped shielding member obtained by hollowing out a circle having the outer diameter of the inner pipe from a disc having the inner diameter of the outer pipe. can.

Also, one aspect of the dredging system according to the present invention is
a barge having an operation room;
A shaft held by the barge and extending to the bottom of the lake;
the underwater working machine that constitutes the dredging device and is attached to the shaft so as to be rotatable and vertically movable;
The controller is provided in the operation room, and controls the turning and raising/lowering of the underwater working machine and the change control of the number of rotations of the actuator.

According to this aspect, the submersible working machine that constitutes the dredging device is attached to the shaft that is held by the barge and extends to the bottom of the lake so as to be capable of rotating and ascending and descending. Dredging can also be performed on the bottom of a deep lake with a dredging device. At this time, since the shaft is stably supported at two points, the barge and the bottom of the lake, the sediment can be stably dredged by the dredging attachment accompanying the movement of the arm of the submersible work machine. Efficient sedimentation dredging according to the plan can be realized.
With this system, dredging can be performed up to the extension range of the arm while rotating the underwater work machine around the shaft. In addition, it will be possible to dredge sediments in a short construction period.

In addition, one aspect of the dredging method according to the present invention is
A dredging method for dredging using an underwater working machine having a dredging attachment attached to the tip of an arm,
The dredging attachment includes:
a pump;
a suction tube and a transport tube communicating with the pump;
a screen surrounding the suction port of the suction tube and having a plurality of openings and cutting bits;
an actuator that rotates the screen;
The dredging is performed while adjusting the rotation speed of the actuator so as not to clog at least one of the suction pipe and the transport pipe.

According to this aspect, according to the change control of the rotation speed of the actuator, the change control of the rotation speed of the screen surrounding the suction port of the suction pipe is executed, for example, by reducing the rotation speed of the screen, the sediment concentration is reduced. It can be lowered to suppress clogging of pipes and pumps.

ADVANTAGE OF THE INVENTION According to the dredging apparatus, the dredging system, and the dredging method of this invention, efficient dredging can be implement|achieved, without clogging a piping and a pump, when dredging sediment using a pump.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram which shows an example of the dredging apparatus which concerns on embodiment, and a dredging system. It is a side view which expands and shows the state in which the dredging apparatus which concerns on embodiment is attached to the shaft so that it can be raised-lowered, and can be rotated. It is a figure which shows an example of the hardware constitutions of the controller in an operation room with peripheral equipment. It is a figure which shows an example of the functional structure of the controller in an operation room. It is a side view of an example of the dredging attachment that constitutes the dredging device, and is a partially cutaway view so that the inside can be visually recognized. FIG. 6 is a view in the direction of arrow VI in FIG. 5 and is a front view of an example of the dredging attachment. 6 is a view taken along line VII-VII in FIG. 5, and is a view for explaining the extending direction of the inclined plate member attached to the screen. FIG. It is a longitudinal cross-sectional view of an example of a suction pipe, showing a state in which sediment is being sucked and fresh water is being supplied. FIG. 9 is a view taken along line VIII-VIII in FIG. 8;

Hereinafter, an example of a dredging device, a dredging system, and a dredging method according to embodiments will be described with reference to the accompanying drawings. In addition, in the present specification and drawings, substantially the same components may be denoted by the same reference numerals, thereby omitting duplicate descriptions.

[Dredging device, dredging system, and dredging method according to the embodiment]
<Dredging equipment and dredging system>
First, an example of a dredging device and a dredging system according to an embodiment will be described with reference to FIGS. 1 to 4. FIG. Here, FIG. 1 is an overall configuration diagram showing an example of a dredging device and a dredging system according to an embodiment, and FIG. It is a side view which expands and shows a state. FIG. 3 is a diagram showing an example of the hardware configuration of the controller in the operation room together with peripheral devices, and FIG. 4 is a diagram showing an example of the functional configuration of the controller in the operation room. Incidentally, FIG. 5 will be referred to as necessary. FIG. 5 is a side view of an example of the dredging attachment that constitutes the dredging device, and is a partially broken view showing the inside of the dredging attachment.

The dredging system 800 is a system for dredging, using a pump, sedimentation SE, which is deposited by sediment flowed together with rainwater, river water, etc., in the dam lake DL. The dredging system 800 includes a barge 400 on which an operation room 550 is mounted, a shaft 200 which is held by the barge 400 and extends to the bottom of the lake, and which is attached to the shaft 200 so as to be freely rotatable and vertically movable. and a dredging attachment 100 attached to the tip of an arm 340 of the underwater working machine 300 . The underwater working machine 300 may be mounted on the shaft 200 so as to be able to turn and move up and down, as shown in the figure, but may also be capable of running on the bottom of the water or on land.

A dredging device 700 is formed by the underwater working machine 300 having the dredging attachment 100 and the controller 600 (operating panel) provided inside the operating room 550 . As shown in FIG. 5, the dredging attachment 100 includes a pump 30, a suction pipe 40 and a transport pipe 35 communicating with the pump 30, and a plurality of openings 65 and cutting bits 64 surrounding the suction port of the suction pipe 40. and an actuator 50 for rotating the screen 60 .

Returning to FIG. 1, the barge 400 is configured to have a substantially rectangular shape in plan view by arranging hollow rectangular parallelepiped floating blocks side by side. An operating room 550 is placed. A cove 410 for shaft insertion is provided in a part of the barge 400, and a shaft fixing tower 500 is installed so as to surround the cove 410 in a U-shape in plan view. The shaft fixing oar 500 is provided with upper and lower keepers and shaft fixing pins (both not shown), and holds the shaft 200 suspended by the crawler crane 540 mounted on the barge 400 with the fixing pins. Meanwhile, the extension shaft 201 is added and removed sequentially.

The barge 400 is towed by a tow barge (not shown) or travels by driving a traveling propeller (not shown) equipped on the barge 400 . The dredging system 800 of the illustrated example is mainly composed of a screen on which the dredging attachment 100 rotates and a pump for sucking sedimentation. Other types of attachments such as drifters may be applied and possible attachments may be mounted on barge 400 .

The shaft 200 is constructed by connecting a plurality of steel pipes, and as shown in FIG. 2, an underwater auger 203 is provided near the tip of the shaft 200, and the casing at the tip is fixed to the bottom of the lake by the underwater auger 203. It's becoming That is, when dredging the sediment SE on the bottom of the lake, the shaft 200 is stably supported at two points by fixing its upper end to the shaft fixing tower 500 and fixing its lower end to the lake bottom.

As shown in FIG. 2, a plurality of racks 202 are attached around the shaft 200 so that the underwater work machine 300 can move up and down in the X1 direction.

The underwater work machine 300 includes an elevating mechanism 310 internally provided with pinions (not shown) that engage with the racks 202 provided on the shaft 200, and a pivoting mechanism 310 that is rotatable around the elevating mechanism 310 in the X2 direction. mechanism 320, and the turning mechanism 320 constitutes the working machine main body.

A boom 330 is rotatably attached to the work machine main body 320, an arm 340 is attached to the tip of the boom 330, the work machine main body 320 and the boom 330 are connected by a hydraulic cylinder mechanism 350A, and the boom 330 and the arm are connected. 340 are connected by a separate hydraulic cylinder mechanism 350B. A dredging attachment 100 is attached to the tip of the arm 340, and the arm 340 and the dredging attachment 100 are further connected by a separate hydraulic cylinder mechanism 350C.

A power cable 511 extending from a generator 510 on the barge 400 is electrically connected to the work machine main body 320 to drive the submersible work machine 300 up and down, turn it, slide the hydraulic cylinder mechanisms 350A, 350B, and 350C, Electric power required for driving the pumps and actuators constituting the dredging attachment 100 is supplied.

Work machine main body 320 rotates around shaft 200 at a predetermined angle and stops, and dredging is performed by dredging attachment 100 while successively extending boom 330 and arm 340. By repeating this over the entire circumference of shaft 200, , in all directions about shaft 200, dredging in the extent of extension of boom 330 and arm 340 is enabled.

A dredging attachment 100 is attached to the tip of the arm 340 . The dredging attachment 100 includes a transport pipe 35 for transporting the dredged sediment SE. A sand pumping flowmeter 36 , a sediment concentration meter 37 , and a pressure gauge 38 are provided inside the transport pipe 35 . A load current meter 31 is provided on the pump 30 provided in the dredging attachment 100 . At least one or two of the sediment flow meter 36, the sediment concentration meter 37, and the pressure gauge 38 may be provided, and the sediment flow meter 36, the sediment concentration meter 37, and the pressure gauge 38 are sucked. It may be provided inside the tube 40 .

When the dredged sediment SE flows through the transport pipe 35, the sediment flow meter 36, the sediment concentration meter 37, the pressure gauge 38, and the load current meter 31 measure the corresponding physical quantities, and the respective instruments measure the physical quantities. The measured data obtained is transmitted to the controller 600 installed in the operation room 550 as needed. The controller 600 configured by a computer compares each received measurement data with a threshold value for each physical quantity stored inside itself, and changes and controls the number of rotations of the actuator 50 that rotates the screen 60 as necessary ( control to reduce the number of revolutions). The content of this control will be described in detail below.

After the dredging of the sediment SE around the fixed shaft 200 is completed, the barge 400 is moved to similarly suspend and fix the shaft 200 to the bottom of the lake. By sequentially repeating the movement of the barge 400 and the dredging of the sediment SE, the sediment SE deposited on the lake bottom of the dam lake DL can be dredged.

As shown in FIG. 1, for example, a temporary pit 560 is provided in one corner of the bottom of the dam lake DL, and the tip of the transport pipe 35 extending from the dredging attachment 100 is fixed to the temporary pit 560. , the sediment SE dredged by the dredging attachment 100 is transported to the temporary placement pit 560 . Instead of transporting the dredged sediment SE to the temporary placement pit 560, it may be transported to a mud discharge pit provided on the water or on the ground.

In addition, the boom 330 and the arm 340 are equipped with goniometers (not shown), and angle data measured by each goniometer are transmitted to the controller 600 in the operation room 550 . In addition, the top position of the shaft 200 is measured by a GPS (Global Positioning System) or a total station, and transmitted to the controller 600 together with measurement data from an inclinometer and a rotary encoder (both not shown) attached to the shaft 200. It is designed to be Based on the angle data and measurement data received by the controller 600, the tip position of the arm 340 of the underwater working machine 300 (attachment position of the dredging attachment 100) can be accurately grasped. It is possible to carry out dredging work without leakage while specifying the position of each time.

Further, the underwater work machine 300 is equipped with a multi-fan beam and an ultrasonic underwater camera (both not shown), and three-dimensional data of the bottom of the lake are transmitted from the multi-fan beam to the controller 600 in the operation room 550. , a three-dimensional image of the lake bottom is displayed on the monitor screen of the controller 600 . In addition, imaging data of the bottom of the lake by the ultrasonic underwater camera is also transmitted to the controller 600 in the operation room 550, the dark bottom of the lake is visualized on the monitor screen of the controller 600, and the operator of the underwater work machine 300 can The underwater working machine 300 and the dredging attachment 100 can be remotely controlled while watching the monitor screen.

Next, an example of the hardware configuration and functional configuration of the controller 600 in the operation room 550 will be described with reference to FIGS. 3 and 4. FIG.

As shown in FIG. 3, the controller 600 includes a CPU (Central Processing Unit) 611, a RAM (Random Access Memory) 612, a ROM (Read Only Memory) 613, a HDD (Hard Disc Drive) 614, and an NVRAM (Non-Volatile RAM). ) 615, etc., which are connected by a system bus so as to be capable of data communication.

The ROM 613 stores various programs and data used by the programs. The RAM 612 is used as a storage area for loading programs stored in the ROM 613 and as a work area for the loaded programs. The CPU 611 implements various functions by processing programs loaded in the RAM 612 . For example, the suction control of the pump 30 is executed according to the stored optimum pump suction amount, and the optimum rotation speed of the screen 60 (rotation speed at which sedimentation SE can be effectively taken into the suction pipe) Rotation control of the actuator 50 is executed. The HDD 614 stores programs and various data used by the programs. The NVRAM 615 stores various setting information and the like.

When an operator operates various control levers and the like in the operation room, the controller 600 controls the operation of various devices (hardware) that constitute the underwater work machine 300 and the dredging attachment 100 . That is, the elevating drive of the elevating mechanism 310 of the underwater working machine 300, the turning driving of the turning mechanism 320 of the underwater working machine 300, the sliding driving of the hydraulic cylinder mechanisms 350A, 350B, and 350C of the underwater working machine 300, and the movement of the dredging attachment 100 Rotation drive of the actuator 50 that rotates the screen 60, suction drive of the pump 30 of the dredging attachment 100, and the like are controlled.

Further, when the sediment SE dredged by the dredging attachment 100 flows through the transport pipe 35, the sediment flow meter 36, the sediment concentration meter 37, the pressure gauge 38, and the load current meter 31 Each measurement data is transmitted to the controller 600 at any time.

As shown in FIG. 4 , the controller 600 has a receiver 602 , a storage 608 , a comparator 604 and a controller 606 .

The receiving unit 602 receives measurement data measured by the sediment flow meter 36, the sediment concentration meter 37, the pressure gauge 38, and the load current meter 31, and stores the data in the storage unit 608 as needed.

The storage unit 608 stores a threshold for the amount of sand lifted, a threshold for soil concentration, a threshold for pressure, a threshold for the amount of dredging specified by the amount of sand lifted and a threshold for soil concentration, and a threshold for load current. For these various thresholds, prior to the implementation work, a test construction is performed in advance, and various physical quantities at the time when the suction pipe 40, the transport pipe 35, and the pump 30 are clogged are specified in this test construction, and the specified physical quantities are used. It is stored in the storage unit 608 as a threshold. The method of specifying the dredging amount (m ³ /h) is as follows. For example, when the sand pumping flow rate is 10 (m ³ /min) and the sediment concentration is 10 (%), the volume of dredged sediment is 10 (m ³ /min) x 60 (min/hour) x 0.1 (10 (%)) = 60 (m ³ /hour). Assuming that the porosity of the dredged soil is 40%, the dredging volume (m ³ /h) can be specified as 60 (m ³ /hour)÷0.6=100 (m ³ /hour).

A comparison calculator 604 compares various measurement data with associated thresholds. Then, when the result of the calculation in the comparison calculation unit 604 is that the measurement data exceeds the relevant threshold value, the control unit 606 executes control to decrease the rotation speed of the actuator 50 .

Here, in the comparison calculation unit 604, the comparison calculation between various measurement data and the specified dredging amount and the threshold value associated with each is executed. Control may be performed to reduce the rotation speed of the actuator 50, or, for example, control may be performed to maintain the rotation speed if all elements do not exceed the threshold value. Discretionary. For example, when executing control to reduce the rotation speed of the actuator 50 when even one element exceeds the threshold value, this content is set in the storage unit 608, and the control unit 606 controls the actuator 50 based on the setting content. change control of the number of revolutions.

For example, when the rotation speed of the actuator 50 is controlled to decrease, while the amount of earth and sand suctioned by the pump 30 is constant, the rotation speed of the screen 60 decreases, and the amount of earth and sand to be cut decreases. As a result, the amount of sediment sucked into the suction pipe 40 through the opening 65 and transported through the transport pipe 35 is reduced, and the concentration of sediment is reduced. By lowering the sediment concentration, it becomes possible to suppress clogging of the suction pipe 40, the transport pipe 35, and the pump 30.

As described above, the dredging method according to the embodiment includes a step of dredging while adjusting the rotation speed of the actuator 50 so as not to clog at least one of the suction pipe 40 and the transport pipe 35. .

<Attachment for dredging>
Next, an example of a dredging attachment that constitutes the dredging device according to the embodiment will be described with reference to FIGS. 5 to 9. FIG. Here, FIG. 5 is a side view of an example of the dredging attachment that constitutes the dredging device, and is a partially broken view showing the inside of the dredging attachment. 6 is a view in the direction of arrow VI in FIG. 5, which is a front view of an example of the dredging attachment, and FIG. 7 is a view in the direction of arrows VII-VII in FIG. It is a figure explaining the extending direction of the inclined board|plate material which is. Further, FIG. 8 is a vertical cross-sectional view of an example of a suction pipe, showing a state in which sediment is being sucked and fresh water is being supplied, and FIG. It is a diagram.

The dredging attachment 100 includes an attachment body 10, a pump 30 (dredge pump) disposed inside the attachment body 10, and a suction pipe 40 attached to the lower end of the pump 30 so as to be in fluid communication with the pump 30. , a screen 60 rotatably attached to the lower end of the attachment body 10 , an actuator 50 for rotating the screen 60 , and a transport pipe 35 communicating with the pump 30 .

The attachment main body 10 includes a pair of left and right side plates 11, a horizontal plate 12 that is horizontally mounted on the front and rear of the lower portion of the side plates 11, and a square tube-shaped frame member that is fixed to the lower ends of the side plates 11 and the horizontal plate 12. 13, and all constituent members are formed from steel plates, hard resin plates, or the like.

The side plate 11 has a side surface bent in the middle, and an attachment plate 20 provided with rotation shafts 21 and 22 rotatably attached to the tip of the arm 340 of the underwater work machine 300 at its upper end. is fixed.

The sediment SE sucked by the pump 30 is transported to the outside of the pump through the transport pipe 35 . The suction pipe 40 attached to the lower end of the pump 30 is a unit pipe composed of a steel straight pipe and a bent pipe, and the lower end of the suction pipe 40 protrudes below the frame member 13 of the attachment main body 10. ing. The suction pipe may be formed only of a straight pipe, or may be formed of a cast iron pipe, a vinyl chloride pipe, or the like other than a steel pipe.

The screen 60 includes a plurality of annular horizontal members 61 arranged at intervals in the vertical direction, and a plurality of annular horizontal members 61 arranged at intervals in the circumferential direction of the plurality of annular horizontal members 61 and welded to each of the annular horizontal members 61. It has a substantially hemispherical shape with a U-shaped longitudinal member 62 connected thereto. A plurality of openings 65 are formed by intersecting a plurality of annular horizontal members 61 and a plurality of vertical members 62 in a grid pattern. The U-shaped vertical member 62 in the illustrated example is connected to the annular horizontal member 61 in such a manner that its lower portion is inclined in the X3 direction, which is the rotation direction of the screen 60 . The screen may have a conical shape, a truncated conical shape, a cylindrical shape, or the like, in addition to the substantially hemispherical shape. Alternatively, the U-shaped vertical member 62 may be connected to the annular horizontal member 61 in a vertical manner without being inclined. Furthermore, the vertical member 62 may be in a straight or slightly curved substantially straight shape, in addition to the illustrated shape in which the vertical member 62 is bent into a U shape.

The annular horizontal member 61 is formed of an annular flat steel, and is arranged so that its wide surface is oriented in the horizontal direction. On the other hand, the U-shaped longitudinal members 62 are formed of flat steel or steel bars. By arranging the annular horizontal members 61 and vertical members 62 made of flat steel such that the thickness surfaces thereof face the outer circumference of the screen 60, a desired opening area is ensured for each opening 65. As shown in FIG.

The shape of the opening 65 is approximately rectangular in the upper and middle stages of the screen 60 and approximately triangular in the lower stage. The maximum dimension of the opening 65 (the length of the diagonal line of the substantially rectangular shape) is such that foreign matter (large boulders, driftwood, sunken wood, and dust contained in the sedimentation SE) of a size that does not clog the suction pipe 40 and the pump 30 is removed. The size is set, and can be set to about 60 mm, for example.

In the screen 60, an inclined plate member 63 whose lower end is inclined in the X3 direction, which is the rotation direction, is connected to a plurality of annular horizontal members 61 by welding or the like. Here, the inclined plate member 63 may be inclined in a curved shape or may be inclined in a straight line. In this manner, a plurality of inclined plate members 63 are attached to a plurality of annular horizontal members 61 in addition to a plurality of vertical members 62 . The inclined plate member 63 is also made of flat steel, for example, and is processed into a U shape like the vertical member 62 . Unlike the vertical member 62 , the inclined plate member 63 is arranged so that its wide surface faces the outer periphery of the screen 60 .

A plurality of cutting bits 64 are attached to the end surface of the inclined plate member 63 on the front side in the rotation direction of the screen 60 at intervals in the longitudinal direction of the inclined plate member 63 .

Here, as shown in FIG. 7, in the screen 60 having a circular outer shape in plan view (or transverse cross-sectional view), the front end surface 63a in the rotation direction is inclined radially outward from the tangential direction of the circle (inclination angle θ), the inclined plate member 63 is attached. This configuration enhances the cutting performance of the cutting bit 64 attached to the end surface 63a.

Dredging of the sediment SE is performed with the screen 60 rotating around the tip of the suction pipe 40 . As a result, when foreign matter such as boulders, driftwood, fallen wood, and dust approaches the screen 60, the foreign matter can be repelled or crushed by the cutting bit 64, so that the opening 65 of the screen 60 is blocked by the foreign matter and the suction pipe 40 is blocked. Blockage and even blockage of the pump 30 are effectively prevented. In addition, the rotating cutting bit 64 can also be used to cut down solidified earth and sand at the bottom of the lake.

In addition, in the screen 60, an inclined plate member 63 having a lower end inclined in the X3 direction, which is the rotation direction, is attached, and a plurality of cutting bits 64 are attached to the end surface of the inclined plate member 63 on the front side in the rotation direction of the screen 60. , when the screen 60 is inserted into the sediment SE while being rotated, the cutting bits 64 located forward and downward in the rotational direction come into contact with the sediment SE in order. Therefore, the screen 60 can be inserted into the sediment SE with as little load as possible, and the sediment SE can be dredged while effectively cutting foreign matter as necessary.

Furthermore, since the inclined plate member 63 is arranged so that its wide surface faces the outer circumference of the screen 60, the plurality of cutting bits 64 are capable of resisting the reaction force acting on the inclined plate member 63 when cutting the foreign matter. , the shear rigidity of the inclined plate member 63 can be ensured (the thickness of the wide surface contributes to the shear rigidity). For example, when the inclined plate member 63 is arranged such that its thickness surface faces the outer periphery of the screen 60 like the vertical member 62, the cutting bit 64 is attached to the wide surface of the inclined plate member 63. The width of the thick surface of the inclined plate member 63 contributes to the shear rigidity against the reaction force from the cutting bit 64, and the shear rigidity is lower than the case where the thickness of the wide surface contributes to the shear rigidity as in the illustrated example. becomes lower.

The actuator 50 is formed by a motor, and a drive shaft 51 of the motor 50 and the base of the screen 60 are connected by a power transmission belt 52 .

As shown in FIG. 5, a water supply port 43 is provided in the middle of the suction pipe 40. When the pump 30 is operated to suck the sediment SE from the suction port of the suction pipe 40, the water supply port 43 The fresh water such as lake water is sucked from the hole, and the sucked fresh water makes it possible to reduce the sediment concentration of the sedimentation SE. In addition, the form which supplies purified water etc. as fresh water from the ground or on board may be sufficient.

Here, with reference to FIGS. 8 and 9, the structure of the suction pipe 40 and the reduction of the sediment concentration of the sediment SE to be sucked will be described.

As shown in FIG. 8, the suction tube 40 is formed of a double tube having an outer tube 41 and an inner tube 42, an outer flow path 44 is formed between the outer tube 41 and the inner tube 42, and an inner An inner channel 45 is formed inside the pipe 42 , and a water supply port 43 is opened in the middle of the outer pipe 41 . A water supply pipe having a predetermined length may be connected to the water supply port 43 and the water supply pipe may protrude from the suction pipe 40 .

The inner diameter of the outer pipe 41 is φ1, the inner diameter of the inner pipe is φ2, the inner diameter of the water supply port 43 formed in the outer pipe 41 is φ3, and the distance from the suction port 41a of the outer pipe 41 to the center of the water supply port 43 is t1. is. Furthermore, the suction port 42a of the inner tube 42 is positioned in the L direction, which is the downstream side in the suction direction, of the suction port 41a of the outer tube 41, and the level difference is t2.

The distance t1 from the suction port 41a of the outer tube 41 to the center of the water supply port 43 is preferably set to a distance that does not allow the scattered sediment SE to enter the water supply port 43 when the sediment SE is sucked. It is better to set it in the trial construction conducted prior to the actual construction. For example, about 1 m can be set as the distance t1.

When the pump 30 is driven to suck water in the Y1 direction, fresh water supplied in the Y2 direction through the water supply port 43 flows through the outer flow path 44 toward the suction port 41a, and flows through the suction port 42a of the inner tube 42 in the Y3 direction. It wraps around and is introduced into the inner channel 45 . Then, the dredged sediment SE sucked in the Y4 direction from the suction port 42a of the inner pipe 42 into the inner flow passage 45 is mixed with the fresh water, and at this time, the concentration-reduced sediment in which the initial sediment concentration of the dredged sediment is reduced by the fresh water is produced. The generated deconcentrated sediment is sucked into the pump 30 in the Y5 direction.

In this way, the fresh water supplied through the water supply port 43 flows through the outer flow path 44 toward the suction port 41a, goes around the suction port 42a of the inner tube 42, and is introduced into the inner flow path 45. Both the dredged soil and freshwater can be sucked from the suction port 42a of the inner pipe 42, and the soil concentration of the dredged soil due to the freshwater can be effectively reduced. As a result, clogging of the pump 30 and the suction pipe 40 due to muddy water with a high sediment concentration can be eliminated.

In addition, since the suction port 42a of the inner pipe 42 is positioned downstream in the suction direction from the suction port 41a of the outer pipe 41, fresh water flows through the outer flow path 44 and flows through the suction port 42a of the inner pipe 42. When introduced into the inner flow path 45 by turning around, the fresh water flowing out without being introduced into the inner flow path 45 is suppressed, and the fresh water supplied to the double pipe 40 is effectively introduced into the inner flow path 45. can be introduced. Here, since the level difference t2 between the suction port 42a and the suction port 41a changes the flow amount of clean water to the outside, the optimum combination of the suction force by the pump 30 and the level difference t2 is also set by test construction. good.

Further, as shown in FIG. 8 , a blocking member 46 that blocks the circulation of fresh water in the outer flow path 44 is provided at a position on the downstream side in the suction direction of the water supply port 43 in the outer flow path 44 . As shown in FIG. 9, the shielding member 46 has a doughnut-like planar shape and completely shields the hollow annular outer flow path 44 .

Since the shielding member 46 is attached at a position downstream of the water supply port 43 in the suction direction, fresh water supplied through the water supply port 43 as shown in FIG. Even if it flows downstream in the suction direction opposite to the 45 side, the flow is blocked by the shielding member 46 and flows in the Y6 direction, which is the flow toward the inner flow path 45 side. As a result, fresh water supplied through the water supply port 43 can be effectively provided to the inner flow path 45 .

In addition, the inner diameter φ1 of the outer pipe 41, the inner diameter φ2 of the inner pipe, and the inner diameter φ3 of the water supply port 43 are all set so that the sediment concentration can be reduced to the target in relation to the suction force of the pump 30. It should be set by test construction or the like. For example, if the sediment concentration is about 20% when fresh water is not supplied, and this sediment concentration may clog the pump 30 or the suction pipe 40, the target sediment concentration, for example, about 10%. The inner diameters φ1, φ2, and φ3 are set in relation to the suction force of the pump 30 so that

For example, when the pump 30 has a lift of 28 m, a flow rate of 6 m ³ /min, and the maximum dimension of the opening 65 of the screen 60 is 60 mm, the inner diameter φ1 of the outer tube 41 is 200 mm, the inner diameter φ2 of the inner tube is 150 mm, and the water supply port 43 can be set to 100 mm.

[Demonstration experiment]
<Outline of experiment>
The present inventors filled a test water tank with water and sand, dredged using a dredging device that simulated the dredging device 700 according to the embodiment, and performed continuous operation in which the dredged water was returned to the water tank via a pipe. A flow meter, a sediment concentration meter, a pressure gauge, and a current sensor were installed in the pump cable to record the sediment flow rate, pressure (head), sediment concentration, and current value. Based on these values, a performance test and operable range verification of the dredging equipment were performed in order to obtain an appropriate screen opening and screen rotation speed (rpm) as a shape that can obtain a target sediment concentration of 10% average.

Dredging attachment capacity: Calculated by dredging capacity (m ³ /h) = average flow (m ³ /min) x 60 (min) x average sediment concentration (%) / 100 / 0.6 (porosity 40%) bottom. In addition, it is desirable for the pump to operate at a rated current value or less (105 A), and when the rated current value is exceeded, 125% of the rated current value (131 A) is set as a threshold, and the current value is suppressed within this range.

<Experimental method>
First, test sand is put in, water is filled, and the inside of the tank is dredged. Specifically, the test water tank is filled with 80 m ³ of sand and filled with water. A backhoe equipped with a dredging attachment is used to dredge the inside of the test tank for about 5 to 6 minutes by turning. The tip opening of the suction pipe of the dredging attachment is adjusted with the opening adjustment plate. Casing rotation speed can be adjusted to any rotation speed by controlling the amount of oil in the backhoe piping section with a control box near the backhoe operator's seat.

Next, piping measurement is performed. The dredged soil is measured for each item through a 20m suction hose and a measurement pipe. Here, each item is pressure (MPa), flow rate (m ³ /min), sediment concentration (%), and current value (A).

Next, it is transported through pipes and sand is discharged. Extend the pipe ahead of the measurement pipe with STK steel pipe and apply an appropriate resistance load to the pump. Based on the well-known Darcy's equation, the first experimental condition was set to a total pipe length of 120 m as a pipe length that can be secured at 8 (m ³ /h) during sand lifting. Next, the pipe was extended to conduct an experiment with a pipe length of 150 m. Waste water passing through the steel pipe section is returned to the test tank for continuous circulation. The drainage section is lashed with a backhoe counter to prevent the hose from swaying. In this experiment, since the drainage part is submerged to the surface of the water, the actual lift is 0 m.

<Experimental results>
The change in the sediment concentration was determined by the change in the tip opening of the suction pipe and the rotation speed of the screen. First, a pipe length of 120 m was continuously dredged at each tip opening and screen rotation speed, and each item was measured. Each data was calculated from the average value of the section where the sediment concentration was stable. When fresh water was sucked under each condition, the flow rate was approximately 9.5 (m ³ /min), and it was confirmed that the tip opening of the suction tube and the rotation speed of the screen did not affect the pump suction performance. . Experimental results are shown in Table 1 below.

The following trends were identified as measured values when sand was sucked.
(Trend 1) When the sediment concentration increases, the pressure and current value increase, and the flow rate decreases.
(Tendency 2) As the tip opening of the suction pipe increases, the sediment concentration increases.
(Tendency 3) As the casing rotation speed (screen rotation speed) increases, the sediment concentration increases.
(Tendency 4) At a sediment concentration of 10%, the rate of decrease in flow rate from fresh water flow rate is 10%.

It was identified that the casing (screen) reliably rakes the earth and sand into the central suction pipe, and as the tip opening of the suction pipe increases, more earth and sand is sucked, resulting in a higher concentration of earth and sand. In addition, since the casing (screen) rotation speed and sediment concentration are in a nearly proportional relationship, it was identified that the sediment concentration can be adjusted by adjusting the tip opening of the suction pipe and the casing rotation speed even under various piping conditions. .

In this experiment, when the casing rotation speed exceeded 40 rpm, the sediment concentration increased and the pump current value became 125% or more of the rated current value of 105 A, and there was concern that the pump would stop or deteriorate due to overload during field work. results have been obtained.

It should be noted that other embodiments may be possible in which other components are combined with the above-described configurations, etc., and the present invention is not limited to the configurations shown here. . Regarding this point, it is possible to change without departing from the gist of the present invention, and it can be determined appropriately according to the application form.

10: Attachment body 30: Pump 31: Load ammeter 35: Transport pipe 36: Sand pumping flow meter 37: Sediment concentration meter 38: Pressure gauge 40: Suction pipe (double pipe)
41: Outer tube 41a: Suction port 42: Inner tube 42a: Suction port 43: Water supply port 44: Outer flow path 45: Inner flow path 46: Shielding member 50: Actuator (motor)
60: Screen 61: Annular horizontal member 62: Vertical member 63: Inclined plate member 64: Cutting bit 65: Opening 100: Attachment for dredging 200: Shaft 300: Underwater working machine 310: Elevating mechanism 320: Turning mechanism (working machine main body)
330: Boom 340: Arm 400: Barge 550: Operation room 560: Temporary placement pit 600: Controller (operation panel)
602: Reception unit 604: Comparison calculation unit 606: Control unit 608: Storage unit 700: Dredging device 800: Dredging system DL: Dam lake SE: Sedimentation

Claims (6)

an underwater working machine having a dredging attachment attached to the tip of an arm;
a controller;
The dredging attachment includes:
a pump;
a suction tube and a transport tube communicating with the pump;
a screen surrounding the suction port of the suction tube and having a plurality of openings and cutting bits;
an actuator that rotates the screen;
The controller executes change control of the rotation speed of the actuator,
At least one of a sediment pumping flowmeter, a sediment concentration meter, and a pressure gauge is attached to the suction pipe and the transport pipe,
A load ammeter is attached to the pump,
The controller has a receiving unit, a storage unit, a comparison calculation unit, and a control unit,
The receiving unit receives measurement data measured by at least one of the sand lifting flowmeter, the sediment concentration meter, the pressure gauge and the load current meter,
The storage unit stores at least one of a sand discharge flow rate threshold, a sediment concentration threshold, a pressure threshold, a dredging amount threshold specified by the sediment discharge flow rate and the sediment concentration, and a load current threshold,
The comparison calculation unit compares the measurement data with a threshold associated with the measurement data,
The dredging apparatus, wherein the controller controls the rotation speed of the actuator to decrease when the measured data exceeds the associated threshold. The screen is
a plurality of vertically spaced annular cross members;
a plurality of U-shaped vertical members spaced apart in the circumferential direction of the plurality of annular horizontal members and connected to each of the annular horizontal members; A plurality of the openings are formed by intersecting the plurality of longitudinal members in a grid pattern,
An inclined plate having a lower end inclined in the rotation direction of the screen is connected to the plurality of annular horizontal members, and a plurality of cutting bits are attached to the front end surface of the inclined plate in the rotation direction of the screen. cage,
The screen has a circular shape in plan view, and an end surface of the inclined plate on the front side in the rotational direction is positioned radially outward from a tangential direction of the circular shape in the plan view of the screen. Item 1. Dredging equipment according to item 1 . The dredging attachment further includes a water supply port in the middle of the suction pipe,
By the operation of the pump, the dredged soil is taken into the suction pipe through the opening of the screen, and fresh water is taken into the suction pipe through the water supply port. 3. A dredging device according to claim 1 or 2 , characterized in that it is sucked into said pump via a suction tube and transported via said transport tube. the suction tube is a double tube having an outer tube and an inner tube;
Fresh water supplied to the suction pipe through the water supply port flows through the outer flow path between the outer pipe and the inner pipe, turns around the suction port of the inner pipe, and flows inside the inner pipe. 4. A dredging device according to claim 3 , characterized in that it is introduced into the channel and sucked by said pump along with dredged material entrained in said inner channel. a barge having an operation room;
A shaft held by the barge and extending to the bottom of the lake;
The underwater working machine constituting the dredging device according to any one of claims 1 to 4 , which is attached to the shaft so as to be rotatable and to be able to ascend and descend,
The dredging system, wherein the controller is arranged in the operation room, and controls the turning and raising and lowering of the underwater working machine and the change control of the number of revolutions of the actuator. A dredging method for dredging using an underwater working machine having a dredging attachment attached to the tip of an arm,
The dredging attachment includes:
a pump;
a suction tube and a transport tube communicating with the pump;
a screen surrounding the suction port of the suction tube and having a plurality of openings and cutting bits;
an actuator that rotates the screen;
A dredging method, wherein dredging is performed while adjusting the rotation speed of the actuator so as not to clog at least one of the suction pipe and the transport pipe.

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