JPS59217840A - Drag head for dredger - Google Patents

Abstract

PURPOSE:To perform highly efficient dredging work while dragging a drag head on the bottom under sea by providing a motor, an excavating cutter drum, an excavation mud water-sending impeller turnable with the cutter drum, a suction port, and a sludge discharge pipe to a sleigh-shaped base plate. CONSTITUTION:A drag head to be dragged on the sea bottom through a wire rope or electrical cable from a dredger is made up of a sleigh-shaped base plate 2, a motor 12 mounted on the base plate 2, a cutter to be turned by the motor 12, a casing to surround the cutter, a suction port 8 through which sea water is sucked into the casing, and a sludge discharge pipe 6. A cutter blade 1a is projectionally provided to the inside of the casing 7 in which the cutter consisting of an inner cylinder as a passage to discharge excavated sludge and an impeller 5 to be turned with the cutter are indwelt. The drag head capable of highly efficient dredging work can thus be obtained.

Description

[Detailed description of the invention] The present invention relates to a drag nod for a dredger.

The various 9 dragheads that have been used in the past have been used exclusively for soft mud soil, but recently drag heads with cutters that can also be used for sandy soil have been developed and put into practical use.

However, with a drag hesode equipped with a cutter, the ability to excavate and collect surface soil from the subsurface soil is improved by installing the cutter, but on the other hand, the suction negative pressure of the dredging pump, which affects the suction capacity, increases the concentration of sand grains in the suction pipe. The mud absorption capacity increases rapidly due to an increase in flow resistance due to the increase in grain size, larger particle size, and more complex structure of the drag head, so the mud absorption capacity has the disadvantage of being relatively inferior to the supply of earth and sand by a cutter.

The present invention was proposed in view of the above circumstances, and an object of the present invention is to provide a high-performance drag rod for a dredger.

To this end, the present invention provides a plurality of cutter blades that are pivotally supported in a direction transverse to the forward direction and protrude in the circumferential direction and axial direction at appropriate intervals on the outer periphery, and a cylindrical inner part along the axis is used as a mixing water passage. An integral rotary cutter, an impeller that is provided on the same axis as the rotary cutter and accelerates the mixed water, and when the rotary cutter and the impeller are pivotally supported, the rest of the rotary cutter, except for the bottom, is It is characterized by comprising a casing that surrounds the whole, a water inlet that opens in the forward direction of the casing, and a mud feed pipe that opens in a portion of the casing that faces the impeller.

An embodiment of the present invention will be explained with reference to the drawings. FIG. 1 is a perspective view showing the first embodiment, FIG. 2 is an enlarged cross-sectional view of FIG. 4 is a longitudinal sectional view showing a second embodiment of the present invention, and FIGS. 5 and 6 are a longitudinal sectional view along V-■ and Vl- of FIG. 4, respectively.
FIG. 3 is a cross-sectional view along Vl.

First, in the first embodiment shown in Figs. 1 to 3, the cutter (general name) ■ is used in the front and back direction of the plywood 20 (the x arrow in Fig. 2 is the forward direction, and the side of the plywood in the forward direction from the cutter is the front side or
, the side in the backward direction from the cutter is called the rear side or rear side. ), and rotates while being supported by bearings 3a and bearing shafts 3b provided at both ends, with a hollow cutter boss le in the center and an outer peripheral part. A plurality of blades 1a are arranged radially and at equal intervals and have crescent-shaped curved cross sections, and a cylindrical space (hereinafter referred to as the inner cavity) is provided between the outer diameter of the boss and the smallest diameter end of each blade. ) is formed.

The cutter disks Ib and lc are saw-shaped and form both ends of the excavation width, as shown in FIG. Bearing shaft part 3 with an inner diameter hole slightly smaller than the inner diameter
The ring-shaped disk 1d, which is integral with the blade b and is located approximately in the middle of the excavation width, is for supplementing the strength of the blade, and a plurality of the ring-shaped disks 1d may be provided as necessary.

The impeller blades 5, which are provided radially in the hollow part between the inner diameter of the bearing shaft part 3b integrally fixed to the cutter disk (outlet side) lc and the diameter of the cutter boss 1e, are arranged in any circumferential direction. The required pump characteristics are maintained by the shape of the blade cross section, the deflection angle, etc., and the structure in which both ends of the blade in the radial direction are fixed to the bearing shaft 3b and the cutter boss 1e, respectively, is a reinforcement material for the bearing shaft 3b, that is, the arm. Also serves as an action.

On the base plate 2, an inner envelope part consisting of a casing 7 that covers the upper half of the cutter and a part of the base plate 2 is designed to reduce the gap as much as possible in the part facing the water bottom soil to prevent water from around the outside. Create a structure that blocks the inflow of water.

On the forward side of the casing 7, an inlet 8 with a necessary and sufficient amount of water is opened with a width spanning the width of the excavation, and is fixedly integrated with the casing through an introduction pipe 9. The gap between the outer surface of the cutter 1 and the inner surface of the inner package is wide enough to be used as the main flow channel for introducing soil flow water from the introduction pipe 9 on the forward side, but on the other side, the gap is in the excavation area of the rotating cutter. (including discs) should be so narrow that they do not touch each other.

At the rear of the bed plate 2, there is an excavation groove (the vertical section is a rectangle whose two sides are the width between the cutter discs (between ib and IC) and the excavation depth, and the excavation trace becomes a band-shaped groove as the excavation progresses, and the bottom surface A rear sled 10 that slides on the ground and can move up and down is installed, and the sled 10 uses a rotation pin 10a at the front end as a rotation axis and is displaced fan-shaped by the operation of a power cylinder 10b installed at the rear, thereby changing the cutter excavation depth. It is possible to set the size arbitrarily.

The 7 sides of the base plate frame 2aa) on the outside of both sides of the excavation groove have a gap that does not touch the water bottom soil surface, and the structure is such that it does not prevent the rear sled from touching the ground within its vertical movable range, and the rear sled is placed in the excavation groove. By fitting and sliding the drag head into the ground, it prevents the drag head from sliding sideways, stabilizes the course, and blocks the flow of water from this part to the inner package.

A plurality of cutting blades 11 (10 in this example) each having a length capable of making a cut corresponding to the cutter excavation depth are arranged on the lower surface of the base plate 2 on the forward side, thereby facilitating cutter excavation. Then, the engine 12, which is installed on the plywood at the rear of the cutter, drives the cutter 1 through the drive unit 13.
And the drive shaft 1e of the impeller blade 5 is rotated.

Front sleds 14 are fixed to both sides of the front part of the base plate so that there is an appropriate gap between the lower surface of the plywood and the soil surface, and the bottom surface of the sleds 14 slides into contact with the underwater soil to stabilize the posture of the drag heel. .

This drag head is suspended from the ship on a wire rope, and the excavation work is controlled so that the front and rear sleds of this drag head touch the ground lightly, and the wire lobes bear most of the weight of the device. In this case, the power for the prime mover 12 is supplied from the ship, and electric current, oil pressure, or other types of power may be selected, and the suction pipe of this device is connected to the dredging pump suction port inside the ship.

In such a device, (1) the cutter 1 cuts the surface layer B of the submerged soil;
The excavated earth and sand B1 riding on the concave curved surface (crescent-shaped) of the blade as it rotates upward is washed by the running water introduced from the inlet 8 on its surface layer, and becomes mixed water and is suppressed into the inner cavity of the cutter. .

The speed of this draghenod when it is being towed by the main ship and moving forward is usually 2 to 4 KT.
kr, which means that the relative flow velocity between this device and the water around the outside is 1 to 2 m/See, and this relative flow rate water should be directly introduced from the inlet 8 on the forward surface of the casing of this device. , the inflow passes through the inlet pipe 9 directly connected to the inlet 8, and the inlet pipe and the cutter blade are connected to the main stream waterway through the forward gap between the outer diameter surface of the cutter and the inner surface of the casing. By shaping and arranging the pipe to form a part of the pipe, the flowing water in the channel is made into an S-shape or a similar flow shape with smooth streamlines, as shown by arrows AI and A2 in FIG.

(2) The inner cavity of the cutter where the mixed water flowing out from between each blade joins is the disc 1C at one end and the bearing shaft 3.
5K, as shown by arrow A3 in Figure 3, is connected in a straight line with the inner diameter hole b, forming a flow path for mixed water, and this mixed water is pumped by the pumping action of the rotating impeller 5 to the outlet of the drag head ( A4 arrow) to the onboard dredging pump (not shown).

According to such a device, the following effects can be achieved.

(]) In addition to the above two effects, the impeller rotates within the drag head, and the pumping action, that is, pumping the mixed water, greatly contributes to reducing the suction negative pressure of the dredging pump, improving excavation efficiency. Mud absorption efficiency can be balancedly improved.

(2) Since excavated soil and sand are mixed by the cutter in the device's internal enclosure, which is isolated from the outside surroundings, dredging work can be carried out without dispersing turbid water.

Next, in the second embodiment shown in FIGS. 4 to 6, an impeller shaft 15 is inserted into the hollow part of the cutter boss 1e, has a bearing part at one end, an impeller blade 16 is attached, and each drive shaft 4 and 15 are branched and shifted by a drive device and driven at an optimum rotation speed.

Since the impeller blade 16 does not have a ring part (corresponding to the bearing shaft part in FIGS. 2 and 3) on its outer diameter, it is provided in the hollow part of the cutter boss 1e near the impeller blade 16 in order to maintain stable rotation. The impeller shaft is supported by the impeller bearing 18.

The cutter arm 17 (Fig. 5) is a cutter boss 1 having a cross-sectional shape as a device for introducing mixed water into the impeller blades.
e It acts as a reinforcing support to fix the end, and the cutter and impeller are rotated in opposite directions and the number of revolutions is set to their respective optimum values. It is possible to balancely improve excavation efficiency and mud absorption efficiency.

In short, according to the present invention, a plurality of cutter blades are pivotally supported in a direction transverse to the forward direction, and a plurality of cutter blades are protruded in the circumferential direction and axial direction at appropriate intervals on the outer periphery, and a cylindrical inner part along the axis is used for mixing. an integral rotating cutter serving as a water passage; an impeller provided on the same axis as the integral rotating cutter and accelerating mixed water;
When the rotary cutter integrated with the impeller is pivotally supported, a casing that surrounds the entire rotary cutter except for the bottom part, and a water inlet opening in the forward direction of the casing, are arranged opposite to the impeller of the casing. The present invention is industrially extremely useful because a high-performance drag head for a dredger is provided by providing a flow pipe that opens at the portion where the drag head is opened.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the first embodiment of the present invention, and FIG. 2 is a perspective view showing the first embodiment of the present invention.
3 is a vertical sectional view along the line ■-1tt in FIG. 2, FIG. 4 is a vertical sectional view showing the second embodiment of the present invention, and FIGS. 5 and 6 are 5A and 5B are cross-sectional views taken along lines v-■ and Vl-Vl in FIG. 4, respectively. ■...Cutter, la...Cutter blade, lb
, lc... Cutter disk, 1d... Ring-shaped disk, 1e... Cutter boss, 2... Base plate, 3a
...Bearing, 31] ...Bearing shaft, 4.
... cutter drive shaft, 5 ... impeller blade, 6 ... flow pipe, 7 ... casing, 8 ... inlet, 9 ...
Water pipe, 10... Sled, 10a... Rotating pin, 10
b... Power cylinder, 11... Cutting blade, 12...
- Prime mover, 13... Drive unit, 14... Front sled, 15... Drive shaft, 16... Impeller blade, 17...
Cutter arm, 18... impeller bearing. Sub-Agent Patent Attorney Masafumi Tsukamoto

Claims (1)

[Claims] An integrated rotary cutter that is pivotally supported in a direction transverse to the forward direction, has a plurality of cutter blades protruding from the outer periphery at appropriate intervals in the circumferential direction and axial direction, and has a cylindrical inner cavity along the axis as a mixing water passage. , an impeller that is provided on the same axis as the cutter unit and accelerates the mixed water; a casing that, when the rotary cutter unit and the impeller are pivotally supported, completely surrounds the rest of the rotary cutter unit except for the bottom; A drag hemlock for a dredger, characterized by comprising a water inlet opening in the forward direction of the casing, and a redundant pipe opening in a portion of the casing facing the impeller.