Pipe material identification device and identification method

Abstract

To provide a pipe material identification device and method that can easily and safely identify the material of pipes buried underground and enable work from a box inaccessible to a human.SOLUTION: The pipe material identification device includes a sensor unit 1 for striking an inner surface of a pipe Ps and detecting the sound, a support base 2 for mounting and fixing the sensor unit 1, an insertion rod 3 to which the support base 2 is attached and for inserting a sensor unit 1 from the ground into a manhole or a vertical hole H of a box and inserting it into the interior of the pipe Ps, a knock switch 4 for operating the sensor unit 1 from the ground, and a PC 5 for recording the sound captured by the sensor unit 1 and analyzing the frequency distribution of the sound. The sensor unit 1 has a hammer 11 having a head that strikes the inner surface of the pipe Ps and a handle extended from the head, a solenoid 12 for swing and moving the hammer 11, and a microphone 13 for converting the sound produced by the hammer 11 into an electrical signal. The sensor unit 1 identifies the material of the pipe Ps on the basis of the analysis results of the frequency distribution by the PC 5.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an apparatus and method for determining the material of a pipe buried underground. [Background technology]

[0002] For example, when repairing sewer pipes, it is necessary to identify the pipe material prior to the work. The pipe material can be easily identified when the pipe is visible, but when the pipe is buried underground, it cannot be identified by visual inspection, so a method of identification can be considered by inserting a small camera into the pipe to take a picture of the inside of the pipe.

[0003] However, if there is water flowing inside the pipe or if dirt or moss has built up over time due to use, it is impossible to tell from the images taken with the small camera.

[0004] On the other hand, the following Patent Document 1 describes a technology that utilizes the fact that the impact sound of a pipe differs depending on the material, by striking the inner surface of a pipe buried underground with a hammer and determining the material of the pipe from the impact sound. However, the description in Patent Document 1 is limited to disclosing a block diagram and a flow chart of the device's functions, and does not refer to the specific configuration of the device or the method of operation on site. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-96763 A Summary of the Invention [Problem to be solved by the invention]

[0006] In such circumstances, if a worker were to enter the manhole's vertical hole, lower a measuring device to the bottom of the hole, and perform the identification work by hitting the inside of the pipe with a hammer, this could be dangerous. There is also the problem that work cannot be performed through the vertical hole of a manhole, which has a smaller diameter than the manhole and is too large for a person to enter.

[0007] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a material discrimination device and method that can easily and safely discriminate the material of pipes buried underground and that can also perform work from manholes that cannot be reached by humans. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a method and device for detecting the sound of a pipe by tapping the inner surface of the pipe, comprising: a sensor unit that taps the inner surface of the pipe and captures the tapping sound; a support base on which the sensor unit is placed and fixed; an insertion rod to which the support base is attached and which is inserted from above ground into a manhole or a vertical hole in a manhole to insert the sensor unit into the inside of the pipe; a tapping switch that operates the sensor unit from above ground; and a PC that records the sound captured by the sensor unit and analyzes its frequency distribution, The sensor unit includes a hammer having a handle extending from a head for striking the inner surface of the tube, a solenoid for swinging the hammer, and a microphone for converting the striking sound of the hammer into an electrical signal. The aim of the present invention is to provide a pipe material discrimination device that transmits the sound of the hammer head striking the inner surface of the pipe via the microphone to the PC, and discriminates the material of the pipe based on the results of the frequency distribution analysis on the PC.

[0009] Then, pipes of various materials are buried underground, and the frequency distribution of the tapping sounds on the inner surface of the pipe is obtained in advance for each material of the pipe as a standard. The insertion rod of the pipe material discrimination device as described above is inserted from the ground into a vertical hole of a manhole or manhole with its length facing up and down, and the sensor unit mounted on a support stand located at the lower end of the insertion rod is inserted into the pipe to be discriminated from the vertical hole, The hammering switch is turned on to activate the solenoid, and the hammer of the sensor unit strikes the inner surface of the tube. They proposed a method for identifying pipe materials in which the hammering sounds captured by the microphone in the sensor unit are stored in the PC, the frequency distribution of the hammering sounds is compared with a reference frequency distribution obtained in advance, and the material with the closest reference frequency distribution is determined to be the material of the pipe to be identified. Effect of the Invention

[0010] According to the method of discrimination using the pipe material discrimination device of this invention, an insertion rod is inserted into a vertical hole of a manhole or manhole from above ground, a sensor unit equipped with a solenoid-driven hammer and a microphone is inserted into the pipe, and a tapping switch on the ground is turned on; this allows an operator to easily perform the discrimination work without having to enter the vertical hole, so that work can be carried out using small vertical holes such as manholes that are inaccessible to humans, and also prevents the occurrence of accidents inside the vertical hole. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic side view showing the overall configuration of a pipe material determination device according to an embodiment of the present invention when in use; [Diagram 2] FIG. 1 is a perspective view showing a sensor unit according to the first embodiment of the present invention; [Diagram 3] Schematic side views showing the state of the inner surface of the pipe before (a) and after (b) being struck by the hammer of the sensor unit of the same [Figure 4] FIG. 1 is a perspective view showing a working state from a vertical hole of the manhole of the same [Diagram 5] Partial side views showing examples of mounting the sensor part with respect to the vertical insertion rod of the same as above, tilted (a) horizontally, (b) 5° upward, (c) 10° upward, and (d) 5° downward. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0013] As shown in Figure 1, in a sewer system, a manhole or a vertical hole H of a manhole located between a small-diameter pipe Ps buried underground and a main pipe Pm opens onto the road surface G above ground. The pipe material discrimination device uses the opening of the vertical hole H to discriminate the material of the pipe Ps.

[0014] This pipe material discrimination device consists of a sensor unit 1 that taps the inner surface of a pipe Ps and captures the tapping sound, a support base 2 on which the sensor unit 1 is placed and fixed, an insertion rod 3 to which the support base 2 is attached and which is inserted into a manhole or vertical hole H of a manhole from the road surface G to insert the sensor unit 1 into the inside of the pipe Ps, a tapping switch 4 that operates the sensor unit 1 from the road surface G, and a PC (personal computer) 5 that records the sounds captured by the sensor unit 1 and analyzes their frequency distribution.

[0015] As shown in Figures 2 and 3, the sensor unit 1 is configured so that, inside a case 10, there are held a hammer 11 having a handle 11b extending from a spherical head 11a that strikes the inner surface of the tube Ps, a solenoid 12 that swings the hammer 11, and a microphone 13 that converts the striking sound of the hammer 11 into an electrical signal, and the handle 11b of the hammer 11 swings around a vibration axis 14 fixed to the case 10.

[0016] The head 11 a of the hammer 11 is a rigid body made of metal, ceramic, plastic, or the like, and projects from and retracts from an opening 10 a in the top surface of the case 10 .

[0017] The handle 11b is made of a hard metal wire with slight elasticity, and its middle part is wound around the bobbin 14a of the oscillating shaft 14 to change direction, while its base end is wound and connected to the connecting shaft 12b of the push bar 12a of the solenoid 12, so that it swings in a seesaw shape around the oscillating shaft 14 as the solenoid 12 is driven.

[0018] The solenoid 12 is connected to the impact switch 4 via a cable 6. When the impact switch 4 is in the OFF state, as shown in FIG. 3(a), the push bar 12a of the solenoid 12 retracts, the part of the handle 11b of the hammer 11 that is further forward than the oscillation axis 14 falls down, and the head 11a of the hammer 11 is immersed in the case 10 of the sensor unit 1.

[0019] On the other hand, when the striking switch 4 is turned ON, as shown in FIG. 3(b), the push bar 12a of the solenoid 12 moves forward, the part of the handle 11b of the hammer 11 further towards the tip side than the oscillation axis 14 stands up, and the head 11a of the hammer 11 protrudes from the case 10 of the sensor unit 1.

[0020] The rise of the head 11a of the hammer 11 is restricted by a stopper 15 fixed to the case 10 abutting against the handle 11b, and lateral swing of the handle 11b is suppressed by a pair of anti-sway guides 16 that sandwich the handle 11b.

[0021] The microphone 13 is disposed close to the head 11 a of the hammer 11 and is connected to the PC 5 via a cable 7 .

[0022] The support base 2 that supports the sensor unit 1 is fixed to the insertion rod 3 via an L-shaped connecting plate 8, and the connecting plate 8 is fastened to the support base 2 and the insertion rod 3 at two points each by fasteners 9a, 9b consisting of bolts, nuts and washers.

[0023] To use the above-mentioned pipe material discrimination device to discriminate the material of a pipe Ps buried underground as shown in Fig. 1, pipes of various materials are buried underground, and the frequency distribution of the tapping sounds of the inner surface of the pipe is obtained in advance for each material as a reference. For example, the small-diameter sewer pipe Ps to be discriminated may be a polyvinyl chloride pipe, a concrete pipe, or a paper pipe with a waterproof coating, so the frequency distribution of the tapping sounds of these pipes is obtained in advance.

[0024] Then, as shown in Figure 4, the pipe material determination device is prepared near a vertical hole H, such as a manhole, that opens on the road surface G on the ground, and the insertion rod 3 is inserted from the road surface G into the vertical hole H with the sensor part 1 facing downward.

[0025] Next, the sensor unit 1 placed on the support stand 2 is inserted into the inside of the pipe Ps from the open end facing the vertical hole H (see Figure 3(a)), the striking switch 4 is turned ON to activate the solenoid 12, and the head 11a of the hammer 11 is used to strike the upper inner surface of the pipe Ps (see Figure 3(b)).

[0026] In accordance with this, the hammering sounds captured by the microphone 13 of the sensor unit 1 are stored in the PC 5, and the frequency distribution of the hammering sounds is compared with a reference frequency distribution obtained in advance, and the material with the closest reference frequency distribution is determined to be the material of the pipe Ps to be distinguished.

[0027] According to the method of discrimination using the pipe material discrimination device as described above, the insertion rod 3 is inserted from above ground into the vertical hole H of a manhole or manhole, the sensor unit 1 equipped with a hammer 11 swung by a solenoid 12 and a microphone 13 is inserted into the pipe Ps, and the striking switch 4 on the ground is turned ON, and the discrimination work can be easily performed without the worker having to enter the vertical hole H.

[0028] For this reason, it is possible to carry out work using a small-diameter vertical hole H that is inaccessible to humans, such as a masu box, and the occurrence of accidents inside the vertical hole H is also prevented.

[0029] In addition, since the sensor unit 1 of this pipe material discrimination device has a relatively simple structure made up of general-purpose parts, it can be provided at low cost, is easy to operate, and is less likely to break down even if the inside of the pipe Ps to be discriminated is dirty with soil, moss, etc.

[0030] The basic configuration of the pipe material discrimination device is such that the support base 2 is horizontal to the vertical insertion rod 3, as shown in Figure 5(a), but in an actual work site, the pipe Ps connected to it may be tilted with respect to the vertical hole H.

[0031] Even in such a case, in order to enable the sensor unit 1 placed on the support base 2 to be smoothly inserted into the inside of the pipe Ps, it is advisable to manufacture support bases 2 inclined by +5°, +10°, or -5° from the horizontal direction with respect to the vertical insertion rod 3, as shown in Figures 5(b) to (d), respectively, so that the appropriate one can be selected depending on the inclination of the pipe Ps. [Explanation of symbols]

[0032] G Road surface H Vertical hole Pm main Ps tube (to be distinguished) 1 Sensor section 2 Support stand 3 Insertion rod 4. Tap switch 5 PC 6 Cable (for connecting solenoid to audible switch) 7 Cable (for connecting microphone to PC) 8 Connecting plate 9a,9b Fixtures 10 Cases 10a opening 11 Hammer 11a Head 11b Pattern 12 Solenoid 12a Push Bar 12b Connection shaft 13. Mike 14 Swing axis 14a Bobbin 15 Stopper 16 Anti-sway guide

Claims

1. The device comprises a sensor unit (1) that captures a tapping sound by tapping the inner surface of a pipe (Ps), a support base (2) on which the sensor unit (1) is placed and fixed, an insertion rod (3) to which the support base (2) is attached and which is inserted from above ground into a manhole or a vertical hole (H) of a manhole to insert the sensor unit (1) into the inside of the pipe (Ps), a tapping switch (4) that operates the sensor unit (1) from above ground, and a PC (5) that records the sounds captured by the sensor unit (1) and analyzes the frequency distribution of the sounds. The sensor unit (1) includes a hammer (11) having a handle (11b) extending from a head (11a) for striking the inner surface of the pipe (Ps), a solenoid (12) for swinging the hammer (11), and a microphone (13) for converting a striking sound of the hammer (11) into an electric signal. A pipe material discrimination device which transmits the sound of the head (11a) of the hammer (11) striking the inner surface of the pipe (Ps) to the PC (5) via the microphone (13) and discriminates the material of the pipe (Ps) based on the analysis results of the frequency distribution in the PC (5).

2. Pipes of various materials are buried underground, and the frequency distribution of the tapping sounds on the inner surface of each pipe is obtained in advance as a standard. The insertion rod (3) of the pipe material discrimination device described in claim 1 is inserted from the ground into a vertical hole (H) of a manhole or manhole with its length facing up and down, and the sensor unit (1) placed on a support stand (2) located at the lower end of the insertion rod (3) is inserted into the pipe (Ps) to be discriminated from the vertical hole (H), The striking switch (4) is turned on to activate the solenoid (12), and the hammer (11) of the sensor unit (1) strikes the inner surface of the pipe (Ps), The method for identifying a pipe material comprises storing the hammering sounds captured by the microphone (13) of the sensor unit (1) in the PC (5), comparing the frequency distribution of the hammering sounds with a previously obtained reference frequency distribution, and determining that the material having the closest reference frequency distribution is the material of the pipe (Ps) to be identified.

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