JPH0616031B2 - Mechanical Impedance Probe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an apparatus for diagnosing the soundness of a gas pipe or the like, which is corroded from the outer surface side of an underground buried pipe, in the buried state, more specifically. Specifically, it relates to a mechanical impedance probe.

<Prior Art> Depending on the material of the pipe buried underground, corrosion or the like on the outer surface of the pipe may hardly cause a problem, and only the state of the inner surface of the pipe may be a problem. In such a case, for example, it is possible to display the state of the inner surface of the pipe by an industrial television that can move inside the pipe, and thereby diagnose the soundness of the pipe, and some proposals have already been made. . However, there are some examples of gas pipes where corrosion on the outer surface side of the tube is much more problematic than that on the inner surface side of the tube. An effective and appropriate diagnostic device in such a case is to run the ultrasonic probe while rotating it in a tube (see Japanese Patent Laid-Open No. 56-42137), or to integrate a hammer and an AE sensor for exciting a subject. (See JP-A-60-120245)
There is a suggestion such as.

<Problems to be Solved by the Invention> When hitting the inner wall surface of an embedded pipe and diagnosing the soundness of the pipe based on the information obtained at that time, a vibration damping member that slides against the pipe wall surface is used. In the case where the vibration of the pipe is prevented from being transmitted to the microphone, it is expected that the vibration isolator will break due to abrasion.

Therefore, the present invention has been made for the purpose of providing a device capable of solving the above-mentioned drawbacks.

<Means for Solving Problems> The present invention has the following configuration in order to solve the above problems. That is, a probe in which a measuring unit and an electric circuit unit are connected in series between the sensor risers at both ends, and the measuring unit has a solenoid for hitting the inner wall surface of the underground buried pipe whose installation position is vertically adjustable. A hammer, a microphone for striking sound measurement suspended by a leaf spring, and an inclinometer for detecting the striking direction are attached, and a drive circuit for a solenoid hammer and a charge amplifier for the microphone are attached to the electric circuit section. is there.

<Example> The following will describe an example shown in the drawings.

This device is classified into a fixed type in which the direction of impact on the inner wall surface of the pipe is constant, and a rotary type in which the direction of impact with the probe axis can be imparted from all directions. In the fixed type, the front centerizer 1, the measurement unit 2, the electric circuit unit 3, and the rear centerizer 4 are connected in series, while in the rotary type,
As shown in FIG. 1, the rotation mechanism unit 5 is further interposed between the measuring unit 2 and the electric circuit unit 3. In any case, a cable A is connected to a high-voltage power source as a power source for driving the transmitter, a transmitter driving pulse generator, and a controller (not shown) including a tilt indicator and the like. The probe is inserted into the underground pipe B from the front centerizer 1 side, and the cable A
Push or pull to move the probe forward or backward. For this reason, the cable A used should be somewhat rigid, and the surface of the cable A should be graduated at intervals of 1 cm, for example.
It may be convenient to measure the position of the inner probe. Alternatively, it is also possible to attach a towing vehicle to the tip of the probe and allow the inside of the pipe B to run by itself.

To explain the details of each part, the front centerizer 1 is one type. One type is a block body 9 provided with a wheel 6 whose position is immovable and a wheel 7 which is always urged outward by a spring 8. It is a thing. This type supports the probe without sinking even if the weight of the entire probe is considerably heavy, but it needs to be replaced with a suitable one when the diameter of the pipe B changes considerably. In the other type, like the rear centerizer 4, the block body 13 is provided with three wheels 12 that are biased radially by springs 11. This type will sink if the weight of the entire probe is rather heavy, but instead, it will be somewhat tube B
It is effective in locating the probe at the center of the tube B even if the diameter changes. The front centerizer 1 in the case of the fixed type shown in FIG. 2 is fixed to the end surface of the mounting plate 14 of the measuring unit 2 by the fixing bolt 10 inserted into the block body 9,
In the case of the rotary type shown in FIG. 3, the front centerizer 1 is mounted around the fixing bolt 10 so that the block body 13 can rotate. In this way, this probe can be moved in the tube B at a constant height at all times by the action of both centerizers 1 and 4. If you do not use the rotating mechanism, you can use a rotating front center riser, but if there is a problem if the striking direction changes while the probe travels inside tube B, use a fixed front center riser. It is more effective to use.

The measuring unit 2 includes a fixing bolt 10 for the front centerizer 1.
A solenoid hammer 15 as a transmitter, a microphone 16 as an in-pipe acoustic sensor, and an inclinometer 17 for detecting a striking direction are attached to a mounting plate 14 connected with each other. As shown in FIG. 4, the solenoid hammer 15 is constructed such that a hammer body 15c is suspended inside a coil 15b built in a casing 15a by spiral leaf springs 15d and 15d, and a pipe B is attached to the tip of the hammer body 15c. The hammer tip 15e that hits the inner wall surface is replaceable. Also,
An accelerometer 18 for measuring the acceleration at the time of impact is screwed to the rear end of the hammer body 15c. Accelerometer 1
Instead of 8, another measuring device such as a force meter may be used. In other words, this makes it possible to obtain signals other than sound. 15f is a damper. The microphone 16 in the vicinity of the solenoid hammer 15 is also suspended inside the support case 16a by spiral leaf springs 16b and 16b to avoid vibration from the mounting plate 14.

When the hammer body 15c repeatedly moves up and down with a constant stroke, in order to reliably hit the inner wall surface of the pipe B with the hammer tip 15e, it is necessary to have a mounting structure that can easily adjust the set position of the solenoid hammer 15 in the vertical direction. . Therefore, in this example, the casing 15 formed on the mounting plate 14
In order that the mounting hole portion for a can be expanded appropriately or tightened in the opposite direction, the mounting hole portion is partially cut away and two parts facing each other are connected by an adjusting screw 19. The solenoid hammer 15 can be moved in the vertical direction by loosening the adjusting screw 19, and the solenoid hammer 15 can be fixed in that position by tightening it in the opposite direction. Reference numeral 20 denotes a set screw for fixing the inclinometer 17. The other end of the mounting plate 14 is directly connected to the end of the electric circuit unit 3 by the mounting vault 21 or the like if the device is the fixed type described above.

The electric circuit unit 3 includes a drive circuit for the solenoid hammer 15, a microphone 16 and a circuit board 23 fixed in the protective cylinder 22.
Or an accelerometer 18 and other charge amplifiers. In order to fix the base plate 23 in the protective cylinder 22, as shown in FIG. 5, two rings are provided which can be fixed to the inner surface of the protective cylinder 22 by tightening a cone-shaped nut 24 with a screw 25 to expand the diameter. Two columns 27 may be attached to the column 26, and the substrate 23 may be fixed on the columns. In that case, the substrate 23 and the like can be completely removed from the protective cylinder 22 simply by loosening the screw 25.

In the case of the rotary type, the other end of the mounting plate 14 of the measurement unit 2 is connected to the end of the rotation mechanism unit 5 by the mounting vault 21 or the like. The rotation mechanism unit 5 includes a stepping motor 28 for rotating the measuring unit 2 and a slip ring 29 for transmitting a signal from the measuring unit 2 smoothly even if the measuring unit 2 rotates in the protective cylinder 30. In addition, the central shaft 32 that rotates via the gear train 31 by the driving of the stepping motor 28 and the outer member that is stationary regardless of such rotation are integrally connected via the bearing 33. .

The measuring unit 2, the rotation mechanism unit 5, the electric circuit unit 3, and the cable A are electrically connected to each other by a connector 34. The cable A is held by a holding member 35 provided at the end of the protective cylinder 22 of the electric circuit unit 3, extends outward through the center of the rear centerizer 4, and is connected to the controller described above.

Next, to describe its usage, since the solenoid hammer 15 which is a transmitter drives the hammer main body 15c with the coil 15b, the force for hitting the inner wall surface of the pipe B with the hammer tip 15e is the current supplied to the coil 15b. Can be changed by a method of controlling the time, that is, by adjusting the pulse width, and the repetition cycle of striking can be changed by appropriately selecting the pulse rate. When the solenoid hammer 15 travels in the pipe B without rotating or while rotating and repeatedly hits, the sound and the direction of the hit are obtained as signals by the microphone 16 and the inclinometer 17. The frequency analysis is carried out by means of, and it is possible to diagnose the abnormal part of the pipe B by the change of the predominant frequency and the change of the amplitude.

<Effect of the Invention> According to the configuration of the present invention, since the installation position of the solenoid hammer 15 can be adjusted in the vertical direction, it is possible to respond immediately when the pipe diameter changes. Further, since the microphone 16 is suspended and held by the leaf springs 16b and 16b, even if the mounting plate 14 vibrates due to impact, the vibration is not transmitted by the interposition of the leaf springs 16b and 16b.
The vibrating section 6 can correctly measure only the impact sound, and the reliability of the diagnosis result can be increased. The suspension holding structure using the leaf springs 16b and 16b described above is excellent in that there is no possibility of wear unlike the one in which vibration is not transmitted by the vibration isolating member that slides against the pipe wall surface. In addition, this configuration can be easily adapted to diagnoses using two types of signals such as sound and acceleration, and sound and distortion, and by mounting the rotation mechanism section 5, it is possible to strike from all directions of 360 °. Therefore, even if the striking direction changes due to the traveling of the probe, it is possible to always correct the striking direction to the intended one. Inclination is always inclinometer 17
You can monitor at.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a mechanical impedance probe according to the present invention, and FIGS. 2 and 3 are side views of the lower half of the fixed type and the rotary type shown in FIG. Half is a sectional view seen from above. FIG. 4 is a partial sectional view showing the structure of the solenoid hammer, and FIG. 5 is a perspective view showing the mounting structure of the electric circuit board. A ... Cable, B ... Pipe buried underground, 1 ... Front centerizer, 2 ... Measuring part, 3 ... Electric circuit part,
15 ... Solenoid hammer, 16 ... Microphone, 16b ... Leaf spring, 17 ... Inclinometer.

Claims (1)

[Claims] 1. A probe in which a measuring section (2) and an electric circuit section (3) are connected in series between the centerizers (1) and (4) at both ends, the measuring section (2) being provided with an installation position. The vertical direction adjustable solenoid hammer (15) for hitting the inner wall surface of the underground pipe, the leaf springs (16b) (16b) for suspending and holding the impact sound measurement microphone (16) and the inclination for detecting the hitting direction. A mechanical impedance probe in which a meter (17) is attached, and a drive circuit for a solenoid hammer (15) and a charge amplifier for a microphone (16) are attached to an electric circuit section (3).