JPH0665944A - Dredging equipment - Google Patents

Abstract

PURPOSE:To improve the workability by a method wherein rotation of an inlet device is made stoppable when alien substances are caught in the inlet device and operation is continued beyond a specified period of time with permissible torque being surpassed. CONSTITUTION:A torque limiter 9b provided to an inlet device 5 sends signals of actual loaded torque to a control device 30. Then, the control device 30 compares, by operation of a comparator, the inputted signals with permissible torque set beforehand, and sends emergency stoppage command to a controller 9a of an electromotor 9 only when the state of exceeding the permissible torque continues beyond a specified period of time set beforehand, and thereby operation of the inlet device 5 is stopped. Thereby damages to equipment can be prevented while the operation can be continued except the event of critical time, and efficiency in the operation can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dredging device used for dredging soft mud such as sludge accumulated in a water intake, a seabed, a lake, a river, a port, etc. of a power plant.

[0002]

2. Description of the Related Art Dredging of sludge such as sludge deposited on the seabed may cause a submersible pump to plunge into the sludge layer and suck it up.
Alternatively, it was done by scooping up the soft mud from the seabed with a grab bucket. However, this method cannot dredge a high-concentration soft mud, and because it absorbs a large amount of seawater together with the soft mud, the sludge efficiency is poor. In addition, the grab bucket method causes turbidity in the seawater. There was a problem of causing secondary pollution.
Therefore, in order to solve these problems, a dredging device consisting of a vertical screw conveyor and an inlet device rotatably arranged at the lower end of this vertical screw conveyor was put into practical use, and it was placed near the upper end of the vertical screw conveyor. The soft mud discharged from the discharge port is pressurized by a pressure pump and pressure-fed to the discharge pipe via the check valve. Further, compressed air is pressure-injected from an air nozzle (ejector) provided in the middle of the discharge pipe for a long distance. The method of transportation was proposed by the applicant.

FIG. 5 shows a conventional dredging device of this type, which is a dredging device 1 provided with a rotatable semi-circular mud collecting plate 11 on the outer periphery of an inlet device 5, in which the mud collecting plate 11 is dredged. After being rotated and opposed to the rear side in the direction, the inlet cutter 5 is slowly moved forward so that the inlet cutter 5b horizontally shears, stirs, and fluidizes the solidified mud layer at the dredging point to form a vertical stream. It is guided to the inside by the suction force due to the rotation of the screw blades 3 of the mold screw conveyor 2, and is moved up by the screw blades 3. At this time, the solidified soft mud is cut into slices by the inlet / cutter 5b and becomes soft and fluidized, but the foreign matter present in the soft mud cannot pass between the inlet / cutter 5b and is eliminated. To be done. The soft mud that has been lifted and transferred by the vertical screw conveyor 2 in this way is discharged from the discharge port 2a at the upper end and is conveyed to the next step.

When the soft mud is hard or has a strong adhesiveness, the soft mud adheres to the inlet cutter 5b itself as the operation continues, and this develops to clog the space between the inlet cutter 5b. The passage of the soft mud deteriorates,
Dredging and transportation capacity will be reduced. As a countermeasure in such a case, the inner surface of the mud collector 11 is projected horizontally and the inlet
The auxiliary cutter 11a, which is present between the cutters 5b, destroys and removes these clogged solid matters.

[0005]

However, when rocks or other foreign substances larger than the gap between the upper and lower inlets / cutters are mixed in the soft mud to be dredged,
During dredging, these foreign substances were scraped together with the inlet cutter, and were blocked by the auxiliary cutter on the back side in the direction of the dredging on the outer periphery of the inlet cutter, which interfered with the rotation of the inlet cutter, causing the inlet cutter to rotate. The rotating power plant and the structural members of the power transmission path could be overloaded, causing serious accidents such as stoppage or damage. Therefore, if a safety mechanism that stops the operation when an overload torque is generated is added to the device as a countermeasure, it is difficult to maintain continuous stable operation in response to an instantaneous overload. .

[0006]

In order to solve the above-mentioned problems, in the dredging device of the present invention, a vertical screw conveyor and an outer peripheral surface rotatably provided at the bottom of the vertical screw conveyor are provided. Dredging device including an inlet device having a plurality of inlet cutters spaced at appropriate intervals, and a substantially semicircular mud collecting plate rotatably disposed on the outer or inner circumference of the inlet device And a torque limiter and a control device for stopping the power unit when the load torque of the power unit of the inlet device exceeds a set torque, and the operating circuit of the power unit is provided with the set torque during operation. An emergency stop circuit for giving a stop command to the power unit is provided when the overload torque to be exceeded lasts for a preset time or longer.

[0007]

In the dredging device of the present invention, when the set torque (permissible torque) input to the torque limiter provided in the power unit of the inlet unit exceeds the set time of the actual load torque, the power unit is operated. An emergency stop command is sent to the power circuit to shut off the power circuit and stop the operation. Therefore, the operation is not continued when the set torque of the load torque is momentarily exceeded, the operation is not stopped, and the emergency stop is started only when the set torque excess time exceeds the set time. After the foreign matter is caught in the inlet device, the emergency stop is applied only when the foreign substance is not destroyed and the rotation of the inlet device is disturbed and the overload condition continues. The operation can be continued even under load.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 to 4 relate to an embodiment of the present invention,
FIG. 1 is a power circuit and operation circuit diagram of a power unit of an inlet device in a dredging device, FIG. 2 is an operation circuit diagram of main parts of the power unit, and FIG. 3 is an overall longitudinal sectional view of the dredging device of the present invention.
FIG. 4 is a plan view taken along line IV-IV of FIG. 3. In the figure, 1
Is a dredging device, 2 is a vertical screw conveyor, 2A is a casing, 2a is a discharge port, 3 is a screw blade, 3a is a rotating shaft, 3b is an electric motor for driving the screw blade, 4 is a casing of an inlet device 5, and 5a is an inlet. A cylinder, 5b is an inlet cutter, 6 is a bearing, 7 is a girth gear, 8 is a pinion gear, 9 is an electric motor, 9a is a controller, 9b is a torque limiter, 10 is a protective cover, 11 is a mud collecting plate, 1
1a is an auxiliary cutter, 12 is a bearing, 13 and 14 are chain wheels, 15 is an electric motor, and 16 is a protective cover.

As shown in the figure, the vertical screw conveyor 2
Has a cylindrical casing 2A and a screw rotating shaft 3a and a screw blade 3 which are arranged in the casing 2A and are driven to rotate by an electric motor 3b at the top. The soft mud is removed from the upper discharge port 2a.

On the other hand, below the casing 2A of the vertical screw conveyor 2, a casing 4 of an inlet device 5 which rotates concentrically and with the same diameter as the casing 2A is suspended via a bearing 6, and an electric motor 9 and a pinion are provided. It can be rotationally driven via the gear 8 and the girth gear 7. At the lower end of the casing 4, inlet-cutters 5b having a toe-shaped plan view as shown in FIG. 4 are attached to the inlet cylinder 5a having a large opening on its side surface in a plurality of stages. As shown in FIG. 4, the inlet cutter 5b is formed in a circular saw shape so as to shear the soft mud layer located on the outer periphery by rotation.

Further, a substantially semi-circular mud collecting plate 11 is disposed on the outer circumference of the casing 4 so as to cover the outer circumference of the inlet cutter 5b and is supported by bearings 12, and the electric motor 15 is provided via chain wheels 13 and 14. It is driven to rotate by. Reference numeral 16 is a protective cover for the chain wheel. A flat plate-shaped auxiliary cutter 11a is arranged on the inner peripheral surface of the mud collecting plate 11 so as to be inserted into the gap between the inlet cutters 5b. Reference numeral 11b is a through hole for passing water.

At the discharge port 2a of the vertical screw conveyor 2, a straight pipe 20, an elbow pipe 21, an electromagnetic flow meter 22, a straight pipe 23,
Check valve 24, pressure pump 25, discharge pipe 26 are connected,
An air pipe 27 is provided at a position near the pressure pump 25 of the discharge pipe 26.
Air nozzle 2 for injecting compressed air supplied by a
7 are provided. As shown in FIG. 1, it is preferable that the pressure feed pump 25 is provided at a position lower than the discharge port 2a, and the air nozzle 27 is provided as close as possible to the discharge port of the pressure feed pump 25. Therefore, the check valve 24 is arranged not on the discharge side of the pressure pump 25 but on the suction side. The electromagnetic flow meter 22 measures the flow rate by detecting the velocity of a transported object that crosses the magnetic field applied to the flow meter.

Next, a power circuit and an operating circuit of the power unit of the inlet unit 5 (specifically, the electric motor 9) will be described. In FIG. 1, an electric motor 9 which is a power unit of the dredging device 1 is driven by energization of an electromagnetic switch MC incorporated in a power circuit X constituted by three-phase AC power supplies R, S and T. On the other hand, the operating circuit Y is a starting or stopping operating circuit Y.
₁ and an operation circuit Y ₂ for emergency stop.
Start with ₁ start pushbutton switch _{B ON,} stops the motor 9 in the stop pushbutton switch _{B OFF.} The torque limit switch LS ₁ is a circuit for starting compensation that continues the operation together with the motor timer TR despite the peak overload torque at the time of starting. Only the overload over the set time of the motor timer TR is passed through the coil #MC. The electromagnetic switch MC for the electric motor is cut off to stop the electric motor 9. on the other hand,
The operation circuit Y ₂ has a configuration as shown in FIG.
If the torque limit switch LS ₂ continues to exceed the set torque for a preset time (set time t _s ) by the timer T, the relay CR operates to de-energize and the electromagnetic switch MC of the power circuit X is disconnected. Be stopped. The electromagnetic switch MC is energized by energizing the coil #MC of the electromagnetic switch MC.

[0014] By setting the time t _s of the timer T to be adopted usually 5 to 10 seconds, for example, the time exceeding the load torque setting torque setting over time t _s as the operating state C of FIG. 6 If it continues, the relay CR operates to stop the electric motor 9 in an emergency, and when the load torque exceeds the set torque for a moment less than 1 second, as in the operating state B of FIG. 6, the emergency stop is performed. Can be prevented.

While using the operation circuit as described above, as shown in FIG. 3, the actual load torque is transmitted from the torque limiter 9b to the control device 30 every moment and compared with the set (allowable) torque by the comparator. The emergency stop command is sent to the controller 9a of the electric motor 9 through the controller (regulator and operator) and the amplifier to stop the operation of the inlet device 5 only when the set torque exceeds a preset fixed time.

As described above, in the dredging device of the present invention, the power unit is provided with the torque limiter, and the motor is operated only when the load torque exceeds the set torque for a time preset by a timer or the like in the operation circuit of the power unit. Since a circuit for emergency stop is provided, it is possible to continue operation without stopping even for momentary overload torque. Therefore, driving operation is easy and unnecessary emergency stop is avoided.

[0017]

EFFECTS OF THE INVENTION In the dredging device of the present invention, continuous operation is performed except when there is a danger of continuous overload torque which may cause damage to the equipment or burnout of the motor, which may interfere with operation. As a result, the operability is improved and the operability is improved.

[Brief description of drawings]

FIG. 1 is a power circuit and operation circuit diagram of a power device for a dredging device according to an embodiment of the present invention.

FIG. 2 is a main part operation circuit diagram of the power unit of the dredging device according to the embodiment of the present invention.

FIG. 3 is an overall vertical cross-sectional view of a dredging device showing an embodiment of the present invention.

4 is a plan sectional view taken along line IV-IV in FIG.

FIG. 5 is an overall vertical cross-sectional view of a conventional dredging device.

FIG. 6 is a load torque fluctuation curve diagram received by the power unit of the dredging device during operation.

[Explanation of symbols]

1 Dredging Device 2 Vertical Screw Conveyor 2A Casing 2a Discharge Port 3 Screw Blade 3a Rotating Shaft 3b Electric Motor 4 Casing 5 Inlet Device 5a Inlet Tube 5b Inlet / Cutter 6 Bearing 7 Garth Gear 8 Torque Cover 9 Pin Controller 9a Controller 9a Controller 11 Mud Plate 11a Auxiliary Cutter 12 Bearing 13 Chain Wheel 14 Chain Wheel 15 Electric Motor 20 Straight Pipe 21 Elbow Pipe 22 Electromagnetic Flowmeter 23 Straight Pipe 24 Check Valve 25 Pressure Feed Pump 26 Discharge Pipe 27 Air Nozzle 27a Air Piping 30 Controller MC motor electromagnetic switch LS ₁ torque limit switch (start compensation) LS ₂ torque limit switch (emergency stop) T timer CR relay X power circuit Y operation circuit Y ₁ operating circuit (for starting and stopping) ₂ operation circuit (emergency stop) _{t s} set time

Claims (1)

[Claims] 1. A vertical screw conveyor, an inlet device provided with a plurality of inlet cutters rotatably provided at a lower portion of the vertical screw conveyor and appropriately spaced apart from each other on an outer peripheral surface, and the inlet device. A dredging device comprising a substantially semicircular mud collecting plate rotatably disposed on an outer circumference or an inner circumference, wherein the power of the inlet device when the load torque of the power device exceeds a set torque. A torque limiter and a control device for stopping the device are provided, and a stop command is issued to the power device when an overload torque exceeding the set torque during operation of the operation circuit of the power device continues for a preset time or more. Dredging device with an emergency stop circuit.