JPH0714321U - Device for detecting mixed-pressure soil sand plugs - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a mixed-pressure air-mixing earth and sand plug detection device capable of reliably detecting passage of an earth-and-sand plug that is pressure-mixed in a pipeline. [Structure] A protrusion member 3 which projects into the pipe via a disturbance prevention rubber 2 is arranged on the upper part of the sand discharge pipe 1, and an AE sensor 4 is attached to the upper surface of the protrusion member 3.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a device for detecting a mixed-pressure sand-and-sand plug, in which sand and sand are sent under pressure by compressed air in a sand discharge pipe.

[0002]

[Prior art]

 Demand for a mixed pressure delivery system that reduces pressure loss by sending high-concentration soft mud to a pipeline by a centrifugal pump and then supplying compressed air to the pipeline to enable long-distance pipeline pressure It has been increasing rapidly in recent years. In this system, it has been confirmed that the sediment that is sent by compressed air in the pipeline is sent as a sediment plug, that is, a plug made of sediment in the pipeline.

Therefore, it is necessary to detect the length and the position of the sediment plug when calculating the flow rate of the sediment that is sent under mixed pressure or when adding a solidifying material to the soil that is sent under mixed pressure. On the other hand, in the past, it was considered to use a pressure sensor to detect the length and position of the sediment plug when conveying the sediment by mixed pressure air feeding, but with the pressure sensor, the passage of the sediment plug is considered. The change in the pipe pressure due to the pressure was not so remarkable, and it was difficult to detect the position of the sediment plug with the pressure sensor.

[0004]

[Problems to be solved by the device]

 The present invention was made in order to solve the problem at the time of detecting the position of the conventional earth and sand plug, and the purpose of the present invention is to ensure that the earth and sand plug that is sent under mixed pressure in the pipeline is passed. The purpose is to provide a detector for mixed-pressure soil-and-sand plugs that can detect.

[0005]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the device for detecting a mixed-air pressure sand-transporting sand plug according to the present invention has a protruding member protruding into the pipe through a disturbance-prevention rubber at the upper part of the sand-discharging pipe for pressure-mixed air-supplying. The feature is that an acoustic emission sensor is mounted on the upper surface of the protruding member, and the earth and sand plug that passes through the sand discharge pipe is located at the point where the acoustic emission sensor, that is, the acoustic sensor, is placed through the protruding member. Since it passes through, the sediment plug can be surely confirmed, and the flow rate of sediment by mixed pressure feeding and the timing of adding the solidifying material to the sediment can be accurately obtained.

[0006]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an enlarged front cross-sectional view of an essential part of a sand discharge pipe in which a device for detecting a mixed-pressure sand-transporting sand plug according to the embodiment is arranged. 1 is a plan view of the main part in the direction AA of FIG. 1, FIG. 3 is a schematic explanatory view of a demonstration experiment in which the device of the present invention is applied to a sand discharging pipe during pressure feeding of a soft mud plug, and FIG. 4 is It is a diagram which shows the data of the experimental result of FIG.

First, the device of the present invention is used in a mixed-air pressure feeding system to supply a compressed air to soil such as soft mud to form a sediment plug in the conduit of the sand discharge pipe 1 and convey it. , Is provided to detect the passage of a sediment plug. Therefore, in FIG. 1, a round hole is bored in the upper part of the sand discharging pipe 1 for sending mixed pressure air, an O-ring 6 is interposed in the round hole, and a flange member 8 is attached with a bolt 7 in advance. Inside the flange member 8, a protruding member 3 that projects into the sand discharging pipe 1 via a disturbance preventing rubber 2 is arranged.

Further, an acoustic emission sensor (abbreviated as AE sensor 4 in the following description) is attached to the upper surface of the protruding member 3. That is, the AE sensor 4 picks up the sound of the earth and sand plug conveyed in the sand discharge pipe 1 when the earth and sand plug comes into contact with the projecting member 3 that protrudes into the pipe line, thereby detecting the passage of the earth and sand plug in that portion. By installing the AE sensor at two points on the sand removal pipe that are separated by a predetermined distance, the time for the sediment plug to pass through one AE sensor and the time for moving between the two AE sensors are detected, and the sediment plug Since the speed and length of the soil can be known, it is possible to calculate the flow rate of sediment sent by mixed pressure by integrating these data.

When the solidifying material is added to the sediment sent under mixed pressure, the length and the position of the sediment plug are detected by the AE sensor 4, so that the solidifying material is only conveyed when the sediment plug is conveyed. May be added. In addition, when the AE sensor 4 is attached, the disturbance prevention rubber 2 is used so that all the sounds other than the sound when the sand plug hits the protruding portion of the protrusion member 3 in the sand discharge pipe 1 are detected. This is to prevent the spread of

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

Therefore, in FIG. 4, the experimental measurement data of the AE sensor 4 is shown by a diagram X, and an image of the flow of the sediment plug P predicted from the measurement data X of the AE sensor 4 is shown in the upper part of FIG. It is shown in diagram Y. In Fig. 4, a pressure gauge is provided as a conventional device for detecting sediment plugs, and the data obtained by detecting the pressure change in the sand discharge pipe is also shown in the diagram Z. It has been proved that the position of the earth and sand plug, which was difficult to detect when the pressure gauge of No. 3 was used, can be surely confirmed by using the AE sensor 4 of the present invention.

[0012]

[Effect of device]

 As described above, according to the mixed-pressure air-mixing sand and sand plug detection device of the present invention, it is possible to reliably confirm that the sand-sand plug passes through the point of the sand discharge pipe where the AE sensor is arranged. It is possible to accurately obtain the timing of sediment flow rate calculation by sending and the addition of solidifying material to the sediment by sending mixed air pressure.

[Brief description of drawings]

FIG. 1 is an enlarged front cross-sectional view of a main part of a sand discharging pipe in which a device for detecting a mixed-pressure sand-transporting sand plug according to an embodiment of the present invention is arranged.

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

FIG. 3 is a schematic explanatory diagram when a demonstration experiment is performed by applying the device of the present invention to a sand discharging pipe during pressure feeding of a soft mud plug.

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

[Explanation of symbols]

 1 Sand removal pipe 2 Disturbance prevention rubber 3 Projection member 4 AE sensor

Continued front page (72) Inventor Haruhisa Wada 1-3 Azencho, Tsurumi-ku, Yokohama-shi, Kanagawa Toa Construction Industry Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A mixed-pressure feed system, wherein a protruding member protruding into the pipe through a disturbance-preventing rubber is provided on the upper part of a sand discharge pipe for sending mixed-pressure air, and an acoustic emission sensor is attached to the upper surface of the protruding member. Sediment plug detection device.