JPH06160091A - Sludge layer measuring apparatus - Google Patents

Abstract

PURPOSE:To provide a sludge layer measuring apparatus which can accurately and automatically determine the type, the depth and the position of a sludge layer. CONSTITUTION:A sludge layer measuring apparatus comprises an impeller 5 suspended at an upper end by a wire rope, coaxially protruding at a lower end of a vertically cylindrical sealed vessel 1 dipped under water and driven by a DC motor 2 contained in the vessel 1, a depth detector 3 attached to the same vessel as that of an encoder attached to the motor 2, and an input/output cable 9 for the motor 2, the encoder 7 and the detector 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sludge layer measuring device for detecting the depth and position of a sludge layer accumulated on the bottom of a lake or the sea.

[0002]

2. Description of the Related Art For example, a sludge layer at the bottom of a lake has a layer that has just become a fluffy sludge as it goes downward from the water surface, and a new sludge layer is below it. Below that, there is an old sludge layer, which is a fairly thin layer with high adhesion. Below that is the rock formation. Conventionally, what is dredged by a dredger is the above-mentioned new sludge layer containing a large amount of nitrogen and phosphorus components.

[0003]

Conventionally, sludge on the bottom of a lake is removed by a dredger in this way. However, at this time, since there is no device for measuring the range and depth of the sludge layer, the depth of the sludge layer is reduced. Regardless of size, it is dredging to a certain depth. As a result, it is not possible to dredge only the sludge layer, and it is possible to dredge up to the rock formation or leave the sludge layer.

The present invention has been proposed in view of the above circumstances, and an object thereof is to provide a sludge layer measuring device for accurately and automatically detecting the type, depth and position of the sludge layer.

[0005]

To this end, according to the present invention, an upper end of a vertical cylindrical airtight container which is suspended by a wire rope and immersed in water is coaxially projected from the lower end of the vertical cylindrical hermetic container, and the DC is housed in the container. An impeller driven by a motor and the DC
An encoder attached to a motor and a depth detector attached to the same container, and an input / output cable for the DC motor, the encoder and the depth detector are provided.

[0006]

According to such a configuration, in FIG. 1, the DC motor in the cylindrical container has a constant rotation speed by the encoder directly connected even if the load applied to the impeller changes. That is, this DC motor has a characteristic that the current increases in proportion to the load if the rotation speed is constant. Therefore, the detection unit uses this characteristic to set the viscosity of the sludge layer as a load, and from the relationship between the load fluctuation and the load current of the DC motor, as shown in FIG.
By determining the old sludge layer having high viscosity and moving the detecting unit downward, the position of the detecting unit from the water surface, that is, the water depth and the thickness of the sludge layer can be measured.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, an embodiment of the present invention will be described. FIG. 1 is an overall perspective view showing its internal structure, and FIG.
Fig. 3 is a side view showing the outline of the procedure for measuring the seabed sludge layer with a bottom mud dredger using the sludge layer measurement device of Fig. 3, and Fig. 3 is a diagram showing the relationship between the impeller load and motor current of the sludge layer measurement device of Fig. 1. 4 is a diagram showing the relationship between the type of sludge layer and the load current of the motor, and FIG. 5 is a flowchart showing the procedure for measuring the sludge layer in FIG.

First, in FIG. 1, reference numeral 1 is a cylindrical container which is long in the vertical direction, and an impeller 5 is coaxially projected at the lower end of the cylindrical container and driven by a DC motor (hereinafter referred to as DC motor) 2 to rotate the same. The number is detected by the encoder 7. Reference numeral 3 is a depth detector built in the upper portion of the cylindrical container 1, and a pressure receiving surface 8 for receiving water pressure is attached to the upper end thereof. Next, in FIG. 2, reference numeral 18 is a control device, which incorporates a sludge discriminator 16 and a depth indicator 17,
8 is installed in the operation room 19. 15 is a bottom mud dredger and 20
Is a mud collector.

In order to dredge sludge on the vast lake bottom with a bottom mud dredger having such a structure, it is important to first measure the position on the lake surface, the depth to the sludge layer, and the thickness of the sludge. Therefore, prior to the dredging work, the sludge detection unit 11 is hung at the tip of the wire rope 10 of the bottom mud dredger.
Then, the bottom mud dredger 15 is moved to a prescribed position on the lake surface, and the detection unit 11 is lowered to the sludge layer to obtain the thickness and the water depth of the sludge layer at that position.
As shown in, the load current changes in proportion to the load of the DC motor. That is, since the load current has different viscosities between the water, the new sludge layer 13 and the old sludge layer 14, the thickness of the sludge layer can be obtained by obtaining the relationship between the load current and the sludge layer. Further, the depth from the water surface of the detection unit 11 is obtained by the depth detector 3 using water pressure, displayed by the depth indicator 17, and the sludge discriminator 16 discriminates sludge. According to the above procedure, the water depth and the thickness of the sludge layer are measured from the surface of the lake at a plurality of points, and a distribution map of the sludge layer is created and stored in the controller.

When dredging with a bottom mud dredger, the procedure is as follows, as shown in FIG. That is, the sludge collector 20 is automatically lowered by the control device 18 while moving the dredger to collect sludge. The measurement of the sludge layer is performed as described above, but rocks and wood may be buried in the sludge. Therefore, when descending the detection unit, the wire rope 10 gradually descends while having tension due to the weight of the detection unit so as to prevent rocks, woods and the like from hitting the sludge layer after reaching the sludge layer. Further, when the impeller 5 hits rocks, wood, or the like, the impeller 5 does not rotate, an excessive current flows, and the impeller may be damaged. Therefore, it is important to provide a protection device for stopping the DC motor 2 when an overload current occurs. Furthermore, by arranging a small camera with illumination in parallel with the sludge detection unit, it is possible to measure the sludge layer at the optimum position while monitoring the sludge state.

[0011]

According to such a sludge layer measuring device,
Since the sludge layer can be detected by hanging the detector from the bottom mud dredger, the following effects can be obtained. (1) The type and distribution of the sludge layer can be determined by detecting the thickness of the sludge and the depth from the water surface while moving the bottom mud dredger. (2) Since the dredging is performed according to the distribution of the sludge layer stored in the control device, only the necessary sludge can be collected, and no sludge remains or the ground layer is dredged. (3) Since the dredging can be performed automatically, labor can be saved and work efficiency is improved.

In short, according to the present invention, the upper end is coaxially projected from the lower end of a vertical cylindrical airtight container suspended by a wire rope and immersed in water, and driven by a DC motor incorporated in the container. By providing an impeller, an encoder attached to the DC motor and a depth detector attached to the same container, and an input / output cable for the DC motor, the encoder and the depth detector, The present invention is extremely useful industrially because a sludge layer measuring device that accurately and automatically detects the type, its depth and position is obtained.

[Brief description of drawings]

FIG. 1 is an overall perspective view showing the internal structure of an embodiment of the present invention.

2 is a sludge layer measurement device of FIG. 1 with a bottom mud dredger,
It is the whole side view showing the state where the seabed sludge layer is being measured.

FIG. 3 is a diagram showing a relationship between a load of an impeller and a motor current of the sludge layer measuring device of FIG.

FIG. 4 is a diagram showing the relationship between the type of sludge layer and the load current of the motor.

5 is a flow chart showing a sled layer measurement procedure according to FIG.

[Explanation of symbols]

 1 Cylindrical container 2 DC motor 3 Depth detector 4 Shaft 5 Impeller 6 Seal part 7 Encoder 8 Pressure receiving surface 9 Cable 10 Wire rope 11 Sludge detection part 12 Water surface 13 New sludge layer 14 Old sludge layer 15 Bottom mud dredger 16 Sludge discriminator 17 Depth Indicator 18 Control Device 19 Operating Room 20 Mud Collector

Claims (1)

[Claims] 1. An impeller driven coaxially to a lower end of a vertical cylindrical airtight container suspended by a wire rope and immersed in water, and driven by a DC motor incorporated in the container. An apparatus for measuring sludge layer, comprising: an encoder attached to a DC motor; a depth detector attached to the same container; and an input / output cable for the DC motor, the encoder, and the depth detector.