JPH11325866A - Detection method for length and speed of air mixed force feed sediment plug - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the detection method of an air mixed force feed sediment plug capable of surely detecting the length, and speed of a sediment plug to be mixed with air and forcibly fed inside a pipe line. SOLUTION: By disposing a projection member 3 projected inside a pipe through disturbance prevention rubber 2 at the upper part of a sand discharge pipe 1 for air mixed force feed, attaching an acoustic emission sensor 4 to the end part on the outside of the pipe of the projection member 3, and picking up sound when the upper end of the sediment plug air mixed and forcibly fed inside the pipe is abutted to the projection member 3, the length and speed of the air mixed forcible feed sediment plug are detected. Also, the speed of the air mixed forcible feed sediment plug can be detected by disposing the projection member at two parts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a mixed pressure sand plug for sending earth and sand through a sand discharge pipe by compressed air.

[0002]

2. Description of the Related Art After a high-concentration ooze is sent out to a transport pipeline by a vortex pump, compressed air is supplied to the pipeline to reduce pressure loss, thereby enabling long-distance pipeline pumping. The demand for systems has increased rapidly in recent years.

[0003] In this system, the earth and sand which is sent under pressure by compressed air in the pipeline is filled with a soil plug,
In other words, it has been confirmed that a plug made of earth and sand is formed and transported.

[0004] Therefore, when calculating the flow rate of the earth and sand fed by the mixed pressure, or when adding the solidifying material to the earth and sand fed by the mixed pressure, it is necessary to detect the length and the position of the earth and sand plug. On the other hand, it has been considered that a pressure sensor was used to detect the length and position of the earth and sand plug when transporting earth and sand by mixed-pressure transport. The change in pressure was not so remarkable, and it was difficult to detect the position of the earth and sand plug by the pressure sensor.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problem in detecting the position of the earth and sand plug. It is an object of the present invention to provide a method for detecting a mixed pressure sand plug capable of reliably detecting the length and speed of a soil plug to be used.

[0006]

According to the present invention, a projecting member projecting into a pipe via a disturbance prevention rubber is disposed on an upper part of a sand discharge pipe for feeding a mixed pressure, and the end of the projecting member outside the pipe is provided. Attaching an acoustic emission sensor to the part, detecting the sound when the upper end of the earth and sand plug that is sent with mixed pressure through the pipe abuts the protruding member, and detecting the length of the earth and sand plug with mixed pressure Protrusion members projecting into the pipe via disturbance prevention rubber are arranged at two separate locations above the sand discharge pipe for air pressure transmission, and an acoustic emission sensor is attached to the end of the protrusion member outside the pipe, A method of detecting the speed of the mixed pressure sand plug by detecting the sound when the upper end of the earth and sand plug coming into the pipe is brought into contact with the protruding member at two places and detecting the moving time of the two places. Consists of

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an essential part of a sand drainage pipe provided with an apparatus for detecting a mixed pressure sand plug according to one embodiment. FIG. 2 is a plan view of an essential part in the AA direction of FIG. 1, and FIG. 3 is a schematic diagram of a verification experiment performed by applying the apparatus of the present invention to a sand discharge pipe during the feeding of an ooze plug. FIG. 4 is a diagram showing data of the experimental results of FIG.

First, an apparatus for carrying out the method of the present invention is a mixed pressure feeding system, in which compressed air is supplied to earth and sand such as ooze to form an earth and sand plug in a pipe of a sand discharge pipe 1 and convey it. This is provided to detect the passage of the earth and sand plug when performing the operation.

Therefore, in FIG. 1, a round hole is formed in the upper part of the sand discharge pipe 1 for sending the mixed pressure air, an O-ring 6 is interposed in the round hole, and a flange member 8 is attached with a bolt 7. Every
A projection member 3 is provided inside the flange member 8 so as to protrude into the sand discharge pipe 1 via a disturbance prevention rubber 2. Further, an acoustic emission sensor (hereinafter, abbreviated as AE sensor 4) is mounted on the upper surface of the protrusion member 3.

That is, the AE sensor 4 makes a sound when the earth and sand plug conveyed in the sand discharge pipe 1 comes into contact with the protruding member 3 protruding into the pipeline, so that the length of the earth and sand plug in that part is reduced. By installing the AE sensor at two points separated by a predetermined distance on the sand discharge pipe, the length of the earth and sand plug is detected by passing through one AE sensor, and the distance between the two AE sensors is detected. Since the time to move is detected, the speed of the earth and sand plug is known.
Furthermore, by integrating these data, it is possible to calculate the flow rate of sediment sent by mixed pressure.

In addition, when the solidified material is added to the earth and sand fed by the mixed pressure, the length and the position of the earth and sand plug are detected by the AE sensor 4, so that the solidified material is only transferred when the earth and sand plug is conveyed. May be added.

When the AE sensor 4 is attached, all the sounds other than the sound when the earth and sand plug strikes the protrusion of the projecting member 3 in the sand discharge pipe 1 are caused by the AE sensor through the disturbance prevention rubber 2. This is to prevent 4 from spreading.

Next, a description will be given of the results of a verification experiment in which the above-described method for detecting a sediment plug according to the present invention is applied to a dredger for high-concentration ooze. An AE sensor 4 attached to the upper part of the sand discharge pipe 1 as shown in FIG. 1 detects the passing sound of the mud plug P flowing in the direction of the arrow F in the sand discharge pipe 1 and detects the passing sound. The signal was amplified by 10, read by a discriminator 12 connected by a coaxial cable 11 of a predetermined length, monitored by an oscilloscope 13, and recorded by an pen recorder 14 or the like to measure data of the AE sensor 4.

Therefore, in FIG. 4, experimental measurement data of the AE sensor 4 is shown by a diagram X, and an image of the flow of the earth and sand plug P predicted from the measurement data X of the AE sensor 4 is shown in the upper part of FIG. This is indicated by a diagram Y.

In FIG. 4, a pressure gauge is provided as a conventional earth and sand plug detecting device, and data obtained by detecting a pressure change in the sand discharge pipe by the pressure gauge is also shown by a diagram Z. It has been demonstrated that the position and length of the earth and sand plug, which were difficult to detect when using a conventional pressure gauge, can be reliably confirmed by using the AE sensor 4 of the present invention.

[0016] With this, when the solidifying material is added to the earth and sand fed by the mixed pressure, not only the position but also the length of the earth and sand plug are known, so that the solidifying material can be supplied to the whole earth and sand plug. Further, the speed of the earth and sand plug can be detected by detecting the time when the earth and sand plug moves between two separated points. This is made possible because the characteristics of each earth and sand plug can be grasped and it is possible to determine which earth and sand plug has passed.

[0017]

As described above, according to the method of detecting a mixed pressure sand plug according to the present invention, it is possible to reliably confirm that the sand plug passes through the point of the sand discharge pipe provided with the AE sensor. In addition, it is possible to accurately calculate the flow rate of the earth and sand by the mixed-pressure feeding and accurately add the solidifying material and the like to the soil and the sand by the mixed-pressure feeding.

That is, by utilizing the fact that the earth and sand plug rises from the bottom of the sand discharging pipe to close the pipe, a projecting member projecting into the pipe through the anti-disturbance rubber is provided on the upper part of the sand discharging pipe for sending the mixed pressure. By installing an acoustic emission sensor at the outside of the tube of the projection member, it became possible to grasp the length of the sediment plugs passing through the plugs of different lengths one by one.

Thus, when the solidified material is added to the earth and sand fed by the mixed pressure, not only the position but also the length of the earth and sand plug is known, so that the solidified material can be supplied to the whole earth and sand plug. .

Furthermore, the speed of the earth and sand plug can be detected by detecting the time when the earth and sand plug moves between two separated points. This is made possible because the characteristics of each earth and sand plug can be grasped and it is possible to determine which earth and sand plug has passed.

[Brief description of the drawings]

FIG. 1 is an enlarged front sectional view of a main part of a sand drainage pipe provided with a mixed pressure sand plug detection device according to one embodiment of the present invention.

FIG. 2 is a plan view of a main part in the AA direction of FIG.

FIG. 3 is a schematic explanatory view when a demonstration experiment is performed by applying the method of the present invention to a sand discharge pipe during the feeding of an ooze plug.

FIG. 4 is a diagram showing data of the experimental results of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sand discharge pipe 2 Disturbance prevention rubber 3 Projection member 4 Acoustic emission sensor

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Haruhisa Wada 1-3 Azazen-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Toa Construction Industry Co., Ltd.

Claims (2)

[Claims] 1. A protruding member projecting into a pipe via a disturbance prevention rubber is disposed on an upper part of a sand discharge pipe for sending a mixed pressure air, and an acoustic emission sensor is attached to an end of the protruding member outside the pipe. A method of detecting the length of a mixed pressure sand plug by listening for a sound when the upper end of a sand plug that is sent mixed pressure through the pipe comes into contact with the protruding member. 2. A projecting member projecting into a pipe via an anti-disturbance rubber is disposed at two distant locations above a sand discharge pipe for mixed-pressure feeding, and at an end of the projecting member outside the pipe, Attach an acoustic emission sensor, pick up the sound when the upper end of the earth and sand plug that is sent with mixed pressure in the pipe comes into contact with the protruding member at two places, and detect the travel time of the two places with the mixed pressure sand plug. How to detect speed.