JP2004011184A - Dredging device and dredging method for lightweight earth and sand - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To a dredging device for lightweight earth and sand capable of efficiently dredging lightweight earth and sand from a lightweight earth and sand accumulation layer without contaminating the water area around a dredging field and force-feeding it to a dredged earth and sand receiving part above water. <P>SOLUTION: The dredging device A comprises a cylindrical moving cylinder T having a substantially horizontal axis, which is suspended from a working vessel B on water; a transport pipe 1 connecting the base end of the moving cylinder To the dredged earth and sand receiving part; a spiral screw 6 housed in the moving cylinder T to forcedly force-feed the dredged earth and sand introduced thereto to the transport pipe 1 side; a main door 7 supported on the moving cylinder T so as to open and close a earth and sand intake port Ti opened to the lower circumferential wall of the moving cylinder T; and an auxiliary door 8 supported on the moving cylinder T to open and close a drain port To opened to the upper circumferential wall of the moving cylinder T. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a dredging apparatus for light-weight earth and sand, which dredges light-weight earth and sand deposited on the bottom of the water, and pumps the dredged water to a dredged earth-and-sand receiving portion above water.
[0002]
In the present invention, the term "light-weight soil" refers to sediment such as sludge and sludge which have a relatively small specific gravity and are liable to diffuse in water in a conventional dredging operation, and water pollution is liable to be a problem.
[0003]
[Prior art]
Conventionally, when dredging lightweight sediment such as sludge and sludge that accumulates on the water bottom, an openable bucket has been used, as in the case of dredging relatively heavy sediment.
[0004]
[Problems to be solved by the invention]
However, when dredging lightweight soil such as sludge and sludge using an openable bucket, the specific gravity of the lightweight soil itself is small and it is easy to spread even with a slight fluid pressure, so the problem of water pollution is likely to occur. Further, depending on the type of the openable bucket, there is a problem that the above-mentioned lightweight earth and sand cannot be grasped efficiently and the work efficiency is lowered.
[0005]
SUMMARY OF THE INVENTION The present invention has been proposed in view of the above circumstances, and provides a light-weight sediment dredging device having a simple structure and a light-weight sediment dredging method using the same device, which can solve the conventional problems at once. The purpose is to do.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a first aspect of the present invention is a lightweight sediment dredging apparatus for dredging lightweight sediment deposited on a water bottom and pumping the dredged soil to a dredged sediment receiving portion above the water. A cylindrical moving cylinder suspended and having a substantially horizontal axis, a transport pipe connecting the base end of the moving cylinder and the dredged soil receiving portion, and a dredger housed in the moving cylinder and introduced therein. A helical screw for forcibly feeding the soil to the transport pipe side, a screw driving means mounted on the moving cylinder so as to forcibly rotate the screw, and a sediment intake opening in a lower peripheral wall of the moving cylinder. A main door supported by the movable cylinder so as to be able to open and close; a main door driving means for forcibly opening and closing the main door; and a movable cylinder so as to be able to open and close a drain port opened in an upper peripheral wall of the movable cylinder. Auxiliary door supported by It is characterized in that an auxiliary door driving means for closed.
[0007]
Further, in addition to the above features, the invention according to claim 2 is characterized in that the movable cylinder is suspended on the work boat via a wire and a support frame, and the main door opens and closes a left half of the sediment intake. At least one left main door pivotally supported by the movable cylinder and at least one right main door pivotally supported by the movable cylinder to open and close the right half. Are driven by main door driving means provided between the support frame and the main doors, respectively. The invention according to claim 3 is characterized in that, in addition to the above features, the screw is The pitch is reduced so as to approach the transport pipe.
[0008]
Further, according to the invention of claim 4, in the dredging method for lightweight earth and sand using the lightweight dredging apparatus for earth and sand according to claim 1, 2, 3 or 4, the movable cylinder is provided with the main door and the auxiliary door fully opened. Descent to the light-weight sedimentary layer of this layer, allowing the sedimentary water and water in the layer to flow into the moving cylinder through the sediment intake port, and allowing excess water to escape from the drainage port, closing the main and auxiliary doors respectively, Rotating the screw to pump the dredged soil in the moving cylinder toward the transport pipe side, lifting the moving cylinder from the lightweight sedimentary layer, and laterally moving the water over the adjacent lightweight sedimentary layer. By repeating the working process of one cycle including the step of descending from the ground, the intermittent dredging of the lightweight sediment from the lightweight sediment layer and the pumping of the lightweight sediment to the dredged sediment receiving portion above the water.
[0009]
According to the features of each of the first to fourth aspects of the invention, with the main door and the auxiliary door fully opened, the movable cylinder is lowered to the lightweight sediment layer at the bottom of the water, and the sediment and water in the layer are collected. To allow the dredged soil in the moving cylinder to be sent to the transport pipe side by allowing the water to flow into the moving cylinder from the inlet, allowing excess water to escape from the drainage port, closing the main and auxiliary doors, and rotating the screw. Can be. Thereafter, the moving cylinder is lifted from the light sedimentary sedimentary layer, moved laterally over the adjacent light sedimentary sedimentary layer, lowered again, and by repeating such a work process, the water area around the dredging site was contaminated. It is possible to intermittently dredge lighter sediment from the lighter sedimentary layer and pump it to the dredged sediment receiving part above the water without the need to perform dredging.
[0010]
In particular, according to the feature of the second aspect of the present invention, the main door that swings open and close can be used as a means for guiding dredged earth and sand (i.e., bucket) into the movable cylinder, thereby improving the efficiency of dredging work.
[0011]
In particular, according to the feature of the third aspect of the invention, by employing the variable pitch screw, the efficiency of pumping the dredged soil from the inside of the moving cylinder to the transport pipe side is increased, and the efficiency of the dredging operation is improved.
[0012]
According to a fifth aspect of the present invention, there is provided a method for dredging lightweight sediment deposited on a water bottom and feeding the dredged sediment to a dredged sediment receiving portion above the water, wherein the shaft is suspended from a workboat above the water and the axis is substantially horizontal. And a transport pipe connecting between the base end of the movable pipe and the dredged soil receiving part, and forcing the dredged soil contained in the movable pipe and introduced there into the transport pipe side. Using a dredging device having a helical screw for pressure feeding, and a main door body supported by the moving cylinder so as to open and close a sediment intake port opened on one of the left and right peripheral walls of the moving cylinder; A step of lowering the cylinder to a lightweight sediment layer at the bottom of the water; and moving the movable cylinder horizontally to the left or right side along the lightweight sediment layer at the bottom of the water while rotating the screw with the main door fully opened. To release the sediment in the layer Together to continuously flow into the moving cylinder from sediment intake of states, characterized by comprising the same and a process for continuously pumped into the transport pipe side screw.
[0013]
According to the above feature of the invention of claim 5, the moving cylinder is lowered to the lightweight sediment layer at the bottom of the water, and the screw is rotated while the main door is fully opened, and the moving cylinder is moved to the lightweight sediment layer at the bottom of the water. Moving the sediment of this layer continuously through the open sediment inlet into the moving cylinder by horizontally moving it along the left and right sides, and continuously pumping it to the transport pipe side with a screw Therefore, light soil can be continuously dredged from the lightweight sediment layer without polluting the water area around the dredging site, and can be pumped to the dredged sediment receiving part above the water.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be specifically described below based on embodiments of the present invention illustrated in the accompanying drawings.
[0015]
1 to 10 show an embodiment of the present invention. FIG. 1 is an overall schematic diagram showing an outline of a dredging operation by a dredging work boat, and FIG. 2 is an arrow 2 in FIG. FIG. 3 is a perspective view showing an essential part of the dredging apparatus, FIG. 4 is a view taken in the direction of arrow 4 in FIG. 3, FIG. 5 is a view taken in the direction of arrow 5 in FIG. 3, FIG. 7 is a sectional view taken along line 7-7 of FIG. 5, FIG. 8 is a sectional view of a main part of a dredging device showing a first dredging work mode, and FIG. 9 is an overall plan view showing a first dredging work mode. 10 is a cross-sectional view of a main part of the dredging device showing a second dredging operation mode (corresponding to FIG. 8), and FIG. 11 is an overall plan view showing the second dredging operation mode (corresponding to FIG. 9).
[0016]
First, in FIGS. 1 and 2, the underwater sediment dredging transport system of this embodiment dredges the sediment from a lightweight sedimentary layer L such as sludge on the water bottom by a dredging device A attached to a dredging work boat B, and Forcibly transported through the transport pipe 1, and the transported sediment is stored in a self-propelled soil carrier B 'near the dredging work boat B, and is transported by the soil carrier B' to a disposal site far from the site water area. Like that.
[0017]
In the hull 2 of the dredging work boat B, a hopper-shaped storage tank P for temporarily storing the dredged soil forcibly transported to the surface through the transport pipe 1 and a downstream end of the transport pipe 1 are stored. Selective communication means S for selectively communicating with the inside of the tank P and the inside of the hopper-shaped sediment storage section 3 of the soil carrier B '; Forcible transfer means D for forcibly transferring the earth and sand to the earth and sand storage part 3 of the earth carrier B 'is provided.
[0018]
The selective communication means S includes a first branch pipe C1 whose tip extends into the storage tank P and a second branch pipe C1 whose tip can arbitrarily enter and exit the earth and sand storage part 3 of the soil carrier B 'laid sideways on the dredging work vessel B. A two-branch pipe C2 and a first or second branch in the transport pipe P interposed between the base ends of the first and second branch pipes C1 and C2 and the downstream end of the transport pipe P. A three-way valve V selectively communicating with the pipes C1 and C2.
[0019]
The second branch pipe C2 has a base end portion fixed to the hull 2 of the dredging work boat B, and a front end portion that is connected to and supported by the base end portion so as to be rotatable around a vertical axis and extends substantially horizontally. The tip portion is located at the standby position (the position indicated by the solid line in FIG. 2) stored on the hull 2 side of the dredging work boat B by the turning, and at the side of the sediment storage section 3 of the soil transport ship B 'laid sideways on the ship B. It is configured to be able to be moved manually or by an actuator (not shown) between a use position (a chain line position in FIG. 2) that protrudes from the camera.
[0020]
The forcible transfer means D includes a transfer pipe 4 that can connect between the storage tank P and the sediment storage section 3 of the soil transport ship B ′, and a sediment stored in the storage tank P via a suction pipe 4 ′. And a pump 5 for pumping the water through the transfer pipe 4 into the earth and sand storage part 3 of the earth carrier B '.
[0021]
The transfer pipe 4 has a base end portion fixed to the hull 2 of the dredging work boat B, and a front end portion which is connected to and supported by the base end portion so as to be rotatable around a vertical axis and extends substantially horizontally. The tip of the ship is extended to the standby position (the position indicated by the solid line in FIG. 2) stored on the side of the hull 2 of the dredging work boat B by the above-mentioned swiveling, and to the sediment storage section 3 side of the soil carrier B 'laid sideways on the ship B. It is configured such that it can be moved manually or with an actuator (not shown) between the used position (a chain line position in FIG. 2).
[0022]
Thus, when the soil carrier B 'is laterally mounted on the dredging work boat B, the three-way valve V of the selective communication means S connects the transport pipe 1 to the soil transport vessel B' via the second branch pipe C2 at the use position. And the dredged soil is directly conveyed into the soil carrier B '.
[0023]
When the soil carrier B 'is not laid sideways on the dredging work boat B, the transport pipe 1 is connected to the storage tank P via the first branch pipe C1 by the three-way valve V of the selective communication means S, and dredging is performed. The earth and sand is temporarily transported and stored in the storage tank P. Then, after waiting for the empty soil carrier B 'to lie on the dredging work ship B, the three-way valve V of the selective communication means S transports the transport pipe 1 again through the second branch pipe C2 to the soil carrier B'. The dredged soil is directly conveyed into the soil carrier B 'by being communicated with the storage part 3, and at about the same time, the sediment stored in the storage tank P is sucked by the pump 5 of the forced transfer means D. It is forcibly transferred into the earth and sand storage part 3 of the soil carrier B 'via the pipe 4' and the transfer pipe 4.
[0024]
Thus, since the dredged soil can be stored in the storage tank P of the dredging work boat B without the soil carrier B 'being near the dredging work boat B, it is necessary to temporarily suspend the dredging work by the dredging device A. Therefore, the dredging operation can be continuously performed regardless of whether or not the soil carrier B 'is near the dredging operation ship B, and the operation efficiency is improved.
[0025]
Next, the structure of the dredging device A attached to the dredging work boat B will be described mainly with reference to FIGS. This dredging device A dredges lightweight sediment such as sludge that accumulates on the bottom of the water and receives the dredged sediment on the water through the transport pipe 1 (in the illustrated example, the storage tank P of the dredging work ship B or the sediment of the soil transport ship B ′). It is used for pumping to the storage part 3).
[0026]
Thus, the dredging device A includes a cylindrical moving cylinder T suspended from the dredging work boat B via the wire W and having an axis extending substantially horizontally, and a base end of the moving cylinder T and the dredged soil receiving portion. The transport pipe 1 that connects between the pipes and the outer diameter that is slightly smaller than the inner diameter of the moving pipe T, is accommodated in the moving pipe T, and forcibly introduces the sediment introduced into the pipe T to the transport pipe 1 side. A helical screw 6, a motor M1 serving as a screw driving means mounted on the tip of the moving cylinder T for driving the screw 6 to rotate, and a sediment inlet Ti opened at least in a peripheral wall of the lower half of the moving cylinder T A main door 7 for opening and closing the main door 7, a main door driving means M2 for forcibly opening and closing the main door 7, and an auxiliary for opening and closing a drain port To which is smaller than the sediment inlet Ti and is open in the upper peripheral wall of the movable cylinder T. A door 8 and auxiliary door driving means M3 forcibly opening and closing the auxiliary door 8; Provided.
[0027]
At least a part (intermediate portion) of the transport pipe 1 is made of a flexible material, so that the moving cylinder T connected to the lower end of the transport pipe 1 can be easily moved up and down. It is now acceptable.
[0028]
The wire W is wound up from a winch (not shown) mounted on the hull 2 of the dredging work boat B and extends so as to be able to be unreeled. Support frame F is suspended. The intermediate portion of the wire W is guided and supported by a crane 10 mounted on the hull 2 so as to be able to turn around a vertical axis. Therefore, by the cooperation of the crane 10 and the winch, the support frame F, and thus the moving cylinder T, can be arbitrarily moved up and down via the wire W and can be swiveled around the swivel axis of the crane 10.
[0029]
The main door 7 opens and closes the left half of a plurality (two in the illustrated example) of sediment inlets Ti, which are opened in the lower half peripheral wall of the moving cylinder T in parallel in the axial direction thereof, respectively. A plurality (two in the illustrated example) of left main doors 7L, 7L whose upper ends are pivotally supported at T and a movable cylinder T to open and close the right halves of the sediment intake Ti, Ti as well. Each upper end is divided into a plurality (two in the illustrated example) of right main doors 7R, 7R pivotally supported so as to be swingable.
[0030]
The main doors 7L and 7R are individually opened and closed by main door driving means M2 and M2 such as hydraulic cylinders provided between the support frame F and the main doors 7L and 7R. Further, a plurality of claw portions 7La, 7Ra which are alternately meshed with each other are similarly arranged on the leading edge portions of the left and right main door bodies 7L, 7R which abut against each other in the closed state, similarly to the conventional dredging glove shell. Is established.
[0031]
In addition, the auxiliary door 8 opens and closes each left half of a plurality of (three in the illustrated example) drainage ports To, which are opened in parallel in the axial direction on the upper half peripheral wall of the movable cylinder T, respectively. A plurality of (three in the illustrated example) left auxiliary door bodies 8L, 8L each of which has a lower end pivotally supported at T, and a movable cylinder T each having a drain port To, which also opens and closes the right half of each drain port To. The lower end is divided into a plurality (three in the illustrated example) of right auxiliary doors 8R, 8R pivotally supported at the lower end. The auxiliary doors 8L and 8R are individually opened and closed by auxiliary door driving means M3 and M3 such as hydraulic cylinders provided between the support frame F and the auxiliary doors 8L and 8R.
[0032]
The screw 6 is formed in a variable pitch type in which the pitch gradually decreases toward the downstream side (that is, as it approaches the transport pipe 1), whereby dredging by the screw 6 from inside the moving tube T to the transport pipe 1 side. The pumping efficiency of soil and sand is improved, and the dredging work efficiency is improved.
[0033]
Further, the base end of the moving tube T is formed in a tapered shape tapering toward the transport tube 1, and a connecting portion between the end portion and the transport tube 1 has one end extending from the inside of the moving tube T toward the transport tube 1. A check valve 11 is provided which allows only directional flow. With this check valve 11, there is no possibility that the earth and sand in the transport pipe 1 will flow back to the moving cylinder T side.
[0034]
Next, a first dredging operation mode using the dredging apparatus A of the present embodiment will be described with reference to FIGS.
[0035]
In this first dredging operation mode, the movable barrel T is lowered to the light-weight sediment layer L on the water bottom with the main doors 7L and 7R and the auxiliary doors 8L and 8R fully opened (see FIG. 8). The sediment and water of the lightweight sedimentary sedimentary layer L flow into the moving cylinder T from the sediment inlets Ti and Ti, and excess water is drained. The first step in which the holes are released from the ports To, To, and To, and then the main doors 7L and 7R and the auxiliary doors 8L and 8R are closed, and then the screw 6 is rotated so that the dredged soil in the movable cylinder T is removed. A second step in which is transported to the transport pipe 1 side, and the movable cylinder T is lifted above the light-weight sedimentation layer L, moved laterally in water over the adjacent light-weight sedimentation layer L, and then lowered again. Work with the third step as one cycle Degree of also repeated several times, so that slide into escalated dredging zone as indicated by the chain line in FIG. Thus, the light-weight soil can be intermittently dredged from the light-weight sediment layer L without causing water pollution due to the light-weight sediment diffusion around the dredging site, and can be pumped to the dredged soil receiving portion above the water.
[0036]
In this case, in the first step, the excess water that has entered the moving cylinder T together with the dredged soil from the sediment inlet Ti, Ti flows out through the drainage ports To, To, To. It can be left efficiently. In the second step, the screws 6 are rotated at a low speed at the same time as the main doors 7L, 7R and the auxiliary doors 8L, 8R are closed, and the rotation speed of the screw 6 is reduced in response to the completion of the closing of all the doors. The conveying pressure may be generated by raising the pressure sufficiently.
[0037]
Further, in moving the moving cylinder T lifted from the lightweight sedimentation layer L in the third step in the water above the adjacent lightweight sedimentation layer L, the crane 10 is turned by a predetermined angle, and / or The dredging work boat B is moved forward or backward by a predetermined stroke (see the chain line in FIG. 9).
[0038]
Next, a second dredging work mode using the dredging apparatus A of the present embodiment will be described with reference to FIGS.
[0039]
This second dredging operation mode is performed only for a specific main door body, that is, all the main door bodies 7R, 7R on the left and right sides, or only the main door body 7R on the upstream side of the screw 6 (ie, on the side far from the transport pipe 1). Is fully opened, the other doors are fully closed (see FIG. 10), and the moving cylinder T is lowered to the light-weight sediment layer L at the bottom of the water so as to be sunk into the layer L by its own weight to a specified depth. In the first step, the screw 6 is rotated while the specific main door 7R is kept fully open, and the movable cylinder T is horizontally moved to one of the left and right sides along the light sediment layer L on the water bottom. As a result, the sediment deposited in the layer L continuously flows into the movable cylinder T from the sediment intake Ti (the right half corresponding to the specific main door 7R) in an open state, and the sediment is rotated. A screw 6 is used to continuously feed to the transport pipe 1 side. And a two-step. Thereby, the light-weight soil can be continuously dredged from the lightweight sediment layer L without causing water area contamination due to the light-weight soil diffusion around the dredging site, and can be pumped to the dredged sediment receiving portion above the water.
[0040]
Although the embodiment of the present invention has been described in detail, the present invention is not limited to the above embodiment, and various design changes can be made.
[0041]
For example, in the embodiment, the first dredging operation mode (FIGS. 8 and 9) corresponding to claim 4 and the second dredging operation mode (FIGS. 10 and 11) corresponding to claim 5 are common dredging. Although the apparatus A can be implemented by any of the above, the present invention may be modified such that a dedicated dredging apparatus may be used in the second dredging work mode. The drainage ports To on the upper peripheral wall of T are omitted (ie, closed), and the other half of the left and right sides of the sediment intake Ti on the lower peripheral wall are omitted (ie, closed), and the auxiliary doors 8R, 8L for opening and closing those ports. The main door 7L may be omitted.
[0042]
【The invention's effect】
As described above, according to the first to fourth aspects of the present invention, light-weight soil is intermittently dredged from the lightweight sedimentary layer without inducing water pollution due to light-weight soil diffusion around the dredging site. Since it is possible to pump to the sediment receiving part, lightweight sediment such as sludge that is easy to spread is targeted for dredging. However, dredging work must be performed accurately while avoiding water pollution due to the diffusion of lightweight sediment during dredging. It can be performed efficiently.
[0043]
In particular, according to the feature of the second aspect of the present invention, the main door that swings open and close can be used as a means for guiding the dredged earth and sand into the movable cylinder (that is, a bucket), so that the efficiency of the dredging operation is improved.
[0044]
According to the feature of the third aspect of the present invention, the efficiency of the dredging operation is improved because the efficiency of pumping the dredged soil from inside the moving cylinder to the transport pipe side is increased by the variable pitch screw.
[0045]
According to the fifth aspect of the present invention, the moving cylinder is lowered to the lightweight sediment layer on the water bottom, and the screw is rotated while the main door is fully opened, and the moving cylinder is moved right and left along the lightweight sediment layer on the water bottom. By moving horizontally to one side, the sediment of the layer can be continuously flowed into the moving cylinder from the open sediment intake port, and can be continuously pumped to the transport pipe side with a screw. It is possible to continuously dredge lightweight sediment from the lightweight sediment layer without inducing water pollution due to the diffusion of lightweight sediment around the dredging site, and to pump the dredged sediment to the dredged sediment receiving part above the water, thus facilitating diffusion. Although the light-weight soil of the present invention is targeted for dredging, the dredging operation can be performed accurately and efficiently while avoiding water pollution due to the diffusion of the light-weight soil during the dredging.
[Brief description of the drawings]
FIG. 1 is an overall schematic view showing an outline of a dredging operation by a dredging work boat showing one embodiment of the present invention. FIG. 2 is a plan view as viewed in the direction of arrow 2 in FIG. 1 FIG. FIG. 4 is a view taken in the direction of arrow 4 in FIG. 3 FIG. 5 is a view taken in the direction of arrow 5 in FIG. 3 FIG. 6 is a view taken in the direction of arrow 6 in FIG. 5 FIG. FIG. 9 is an overall plan view showing a first dredging operation mode. FIG. 10 is an overall plan view showing a first dredging operation mode. FIG. (Corresponding to Fig. 8)
11 is an overall plan view showing a second dredging work mode (a diagram corresponding to FIG. 9).
[Explanation of symbols]
B Dredging work vessel F Support frame L Lightweight sediment layer M1 Motor M2 as screw drive means Main door drive means M3 Auxiliary door drive means P Reservoir T of dredging work vessel as receiving part of dredged earth and sand on water Transfer cylinder Ti Earth and sand Inlet To Drainage port W Wire 1 Transport pipe 3 Sediment storage part 6 of screw carrier as a receiving part of dredged soil on water 6 Screw 7 Main door 7L Left main door 7R Right main door 8 Auxiliary door

Claims (5)

In a lightweight sediment dredging system that dredged lightweight sediment deposited on the water floor and pumped it to the dredged sediment receiving part above the water,
A cylindrical moving cylinder (T) suspended from a watercraft work boat (B) and having a substantially horizontal axis, and a transport pipe () connected between a base end of the moving cylinder (T) and the dredged soil receiving portion. 1) a helical screw (6) forcibly pumping the dredged earth and sand contained in the moving cylinder (T) and introduced therein to the transport pipe (1) side, and the screw (6) can be forcibly rotated. And a screw drive means (M1) mounted on the moving cylinder (T) and a sediment inlet (Ti) opened on a lower peripheral wall of the moving cylinder (T) so as to be able to open and close. T), a main door drive means (M2) for forcibly opening and closing the main door (7), and a drain port (To) opened on the upper peripheral wall of the movable barrel (T). And an auxiliary door forcibly opening and closing the auxiliary door (8) supported by the movable cylinder (T) so that the auxiliary door can be opened and closed. Characterized in that a drive means (M3), light sediment for dredging device. The moving cylinder (T) is suspended from the work boat (B) via a wire (W) and a support frame (F), and the main door (7) is a left half of the sediment inlet (Ti). At least one left main door body (7L) pivotally supported by the movable barrel (T) to open and close, and at least one right main door pivotally supported by the movable barrel (T) to also open and close the right half. And a main door driving means provided between the support frame (F) and the main doors (7L, 7R). 2. The dredging device for lightweight earth and sand according to claim 1, wherein the device is driven to open and close by (M2, M2). The dredging apparatus according to claim 1, wherein the screw (6) is formed to have a smaller pitch as the screw (6) approaches the transport pipe (1). A dredging method for lightweight sediment using the dredging device for lightweight earth and sand according to claim 1, 2, or 3,
With the main door (7) and the auxiliary door (8) fully opened, the movable cylinder (T) is lowered to the light-weight sedimentary layer (L) at the bottom of the water, and the sedimentary sediment and water in the layer are taken in by the sediment inlet ( Ti) into the moving cylinder (T) and allow excess water to escape from the drain (To);
Closing the main door (7) and the auxiliary door (8) and rotating the screw (6) to pump the dredged soil in the moving cylinder (T) toward the transport pipe (1);
Lifting the movable cylinder (T) from the light-weight sedimentary layer (L), laterally moving the water over the adjacent light-weight sedimentary layer (L), and then lowering it again as one cycle. A dredging method for lightweight sediment, characterized by intermittently dredging lightweight sediment from the lightweight sedimentary layer (L) and pumping it to a dredged sediment receiving portion above water by repeating. In a dredging method for lightweight sediment that dredged lightweight sediment deposited on the water bottom and pumped it to the dredged sediment receiving part above the water,
A cylindrical moving cylinder (T) suspended from a watercraft work boat (B) and having a substantially horizontal axis, and a transport pipe () connected between a base end of the moving cylinder (T) and the dredged soil receiving portion. 1) a helical screw (6) forcibly pumping the dredged earth and sand contained in and introduced into the moving tube (T) to the transport pipe (1) side, and one of the left and right sides of the moving tube (T) Using a dredging device (A) having a main door (7R) supported by the movable cylinder (T) so as to open and close a sediment intake port (Ti) opened on the peripheral wall of
Lowering the moving cylinder (T) to a lightweight sediment layer (L) at the bottom of the water;
While moving the screw (6) with the main door (7R) fully opened, the moving cylinder (T) is horizontally moved to one of the left and right sides along the lightweight sediment layer (L) at the bottom of the water. As a result, the sediment deposited in the layer is continuously flowed into the moving cylinder (T) from the sediment inlet (Ti) in an open state, and is continuously fed to the transport pipe (1) by the screw (6). A dredging method for lightweight earth and sand.

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