JPH0666773A - Pipe interior inspecting device - Google Patents

Abstract

PURPOSE:To easily detect a constricted part in a pipe from the outside. CONSTITUTION:When the tracer 2 of a capsule A for inspection is caught by a constricted part 14 in a pipe 12, an acoustic signal generator incorporated in the capsule A outputs an acoustic signal and microphones 15 and 16 detect the acoustic signal. By detecting the distance L1 or L2 to the capsule A from the microphone 15 or 16 based on the time lag found when the microphones 15 and 16 detect the acoustic signal, the location of the constricted part 14 is specified. Since the constricted part 14 can be detected when the capsule A is thrown in a fluid, the outage of a plant, etc., is not required at the time of performing the inspection and the inspection can be easily carried out with high workability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe inspecting apparatus capable of easily inspecting a narrowed portion formed in a pipe of a boiler, a chemical plant or the like due to an influence of rust or the like.

[0002]

2. Description of the Related Art As is well known, when a protrusion is formed in a pipe of a boiler, a chemical plant or the like due to rust or accumulation of foreign matter, the pipe line is narrowed and the fluid flow is hindered. Therefore, conventionally, various in-pipe inspection devices have been devised and adopted which inspect the inside of the pipe regularly or irregularly to detect a narrowed portion.

An example of this type of in-pipe inspection apparatus is disclosed in Japanese Patent Laid-Open No. 64-54235.
An image pickup device is mounted on an in-pipe inspection pig running in a pipe, and a defect state in the pipe is detected from an image in the pipe taken by this image pickup device, or as disclosed in Japanese Utility Model Laid-Open No. 59-78963. There is an in-pipe inspection device with a cable that inspects the inside of the pipe.

[0004]

The above-mentioned pipe inspection pig is
In addition to the above-mentioned image pickup device, the pig main body has an image detection unit, an inspection device, a recording device, a power supply, etc. built-in, and sequentially records the image in the pipe to the recording device while being moved by the fluid in the pipe However, the shape of the pig main body becomes large, and the inside of a small-diameter tube such as a heat exchanger cannot be inspected, so that the applicable range is limited.

On the other hand, in a pipe inspection device with a cable,
At the time of inspection, the operation of the plant must be temporarily stopped, which is not only inconvenient to handle, but also has the disadvantage that the inspection range is limited because of the cable.

By the way, for example, Japanese Utility Model Publication No. 50-19744.
The publication discloses a medical capsule that detects radiation inside the human body and transmits the detection result to the outside by a high frequency signal, but this prior art does not disclose any means for inspecting the inside of the tube. Therefore, it is difficult to apply it directly to the industrial field.

The present invention has been made in view of the above circumstances, and provides an in-pipe inspection device which can easily detect a narrowed portion in a thin tube without stopping the plant and has good handleability. It is an object.

[0008]

In order to achieve the above object, the in-pipe inspection device according to the present invention is provided with a plurality of contact members which can be hooked on a narrowed portion of the inside of the pipe on the outer periphery of the inspection capsule which can flow in the pipe. In addition to the above, the inspection capsule has acoustic signal generating means built-in, and signal detecting means for detecting an acoustic signal from the acoustic signal generating means is provided outside the tube.

[0009]

[Operation] In the above structure, when the inspection capsule is flowed along the fluid in the tube and the contact member provided on the outer periphery of the inspection capsule is hooked at the squeezed portion, the acoustic signal generated in the inspection capsule is generated. The position of the squeezed portion is obtained by detecting the acoustic signal from the means by the signal detecting means provided outside the tube.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 6 show a first embodiment of the present invention,
Fig. 1 is a cross-sectional view of a state in which a test capsule is poured into a pipe, Fig. 2 is an external view of the test capsule, Fig. 3 is a cross-sectional view of main parts of the test capsule, and Fig. 4 is a view taken along the line IV-IV of Fig. 3. 5, FIG. 5 is a circuit diagram of the acoustic signal generating means incorporated in the inspection capsule, and FIG. 6 is an explanatory diagram of the method for detecting the position of the narrowed portion.

In FIG. 2, reference numeral A is an inspection capsule,
Reference numeral 1 denotes a capsule body of this inspection capsule, which has a spherical shape and a stylus 2 which is an example of a contact member on the outer periphery.
There are multiple projections.

A pivot ball 2 is provided at the root of each needle 2.
a is formed, and the pivot ball 2a is swingably supported by the hinge 3 embedded in the capsule body 1. The stylus 2 and the hinge 3 are electrically connected.

The middle of the stylus 2 is inserted through the conductive rubber 4 embedded in the capsule body 1, and the electrode plate 5 is arranged on the negative side of the conductive rubber 4.

An acoustic signal generator 6 as shown in FIG. 1 is built in the capsule body 1. An electrode plate 5 arranged on each of the conductive rubbers 4 is connected to an analog multiplexer 7 of the acoustic signal generator 6, and the analog multiplexer 7 is connected to a CPU 10 via an amplifier 8 and an A / D converter 9. Has been done. The analog multiplexer 7 selects and takes in the output signal from each electrode plate 5 at a predetermined timing in accordance with a command from the CPU 10.

Further, the CPU 10 is the piezoelectric speaker 1
Connected to 1.

On the other hand, reference numeral 12 in FIG. 5 is piping for boilers, chemical plants, etc., and 13 is a projection formed in the piping 12 due to the influence of rust, scratches, or the like. A narrowed portion 14 is formed in the pipe 12 by the portion 13.

The length of each of the stylus 2 is set in advance so that it can be engaged when the narrowed portion 14 has a diameter smaller than a predetermined value.

Further, outside the pipe 12, first and second microphones 15 and 16 are arranged at a predetermined interval.

The microphones 15 and 16 are connected to a computing means (not shown), and the computing means is based on the sound emitted from the piezoelectric speaker 11 of the inspection capsule A supplemented by the microphones 15 and 16. Each microphone 15,
The distances L1 and L2 between 16 and the narrowed portion 14 are determined.

Next, the operation of the embodiment having the above structure will be described.

When inspecting the inside of the pipe 12, first,
First and second microphones 15 and 16 are arranged at a predetermined distance on the upstream side and the downstream side of the inspection portion of the pipe 12, respectively. Next, the inspection capsule A is supplied into the pipe 12. The fluid normally flows in the pipe 12, and the inspection capsule A moves along the flow of the fluid.

Then, the inspection capsule A is connected to the pipe 12.
At least one of the plurality of stylus 2 projecting from the capsule body 1 when passing through the narrowed portion 14 formed by the protruding portion 13 inside the narrowed portion 14 as shown in FIG.
When the capsule body 1 is hooked on the inner surface or the protrusion 13, the conductive rubber 4 supporting the base of the stylus 2 is compressed or pulled by the amount that the capsule body 1 is pushed by the flow of the fluid.

As a result, the resistance value between the stylus 2 supported by the conductive rubber 4 and the electrode plate 5 changes. The acoustic signal generator 6 built in the capsule body 1 detects the force acting on each of the stylus 2 from the change in the resistance value between the stylus 2 and the electrode plate 5. That is, in the acoustic signal generator 6, the analog multiplexer 7 sequentially takes in the force acting on each of the stylus 2 in accordance with a command from the CPU 10, converts the force into a voltage value, amplifies the voltage value with the amplifier 8, and then the A / D converter 9 Output to.

Then, the voltage value A / D converted by the A / D converter 9 is output to the CPU 10, and this CPU
When the force applied to each of the stylus 2 is equal to or more than the set value and the force is maintained for the predetermined time, the piezoelectric speaker 11 emits an acoustic signal.

The acoustic signal emitted from the inspection capsule A is detected by the two microphones 15 and 16 which are an example of signal detecting means attached to the outside of the pipe 12.

Based on the acoustic signals detected by the microphones 15 and 16, the distance L1 between the microphones 15 and 16 and the narrowed portion 14 is calculated by an external calculation means (not shown).
, L2 is calculated from the following equation.

The time taken for the acoustic signal to be transmitted from the test capsule A, which is the sound source, to the first microphone 15 is t1 (sec
), When the time from when the acoustic signal is transmitted from the inspection capsule A to the second microphone 16 is t2 (sec), the time T during which the acoustic signal is transmitted between the two microphones 15 and 16 is T = t1 + t2 ... (1) and the time difference Δt between the microphones 15 and 16 is
If t2> t1 is a positive direction, .DELTA.t = t2-t1 (2) (see FIG. 6).

From the first microphone 15 to the inspection capsule A
The distance L1 to is L1 = t1.C0 ... (3) C0: the speed of sound in the fluid (m / sec), and t1 is (1),
Since t1 = (T-Δt) / 2 from the formula (2), the above formula (3) becomes L1 = {(T-Δt) / 2} · C0 ... (4), and the distance L1 becomes the distance L1 from the time difference Δt. Can be calculated.

Similarly, the distance L2 from the second microphone 16 to the inspection capsule A is L2 = t2.C0 ... (5) t2 = (T + Δt) / 2 ∴L2 = {(T + Δt) / 2}. C0 ... (7)

As a result, the position of the inspection capsule A hooked on the narrowed portion 14 of the pipe 12 is set to the microphones 15 and 16 described above.
It can be easily calculated from the acoustic signal detected in.

(Second Embodiment) FIG. 7 and thereafter show a second embodiment of the present invention, FIG. 7 is a schematic view of an inspection capsule moving in a pipe, and FIG. 8 is an inspection capsule hooked at a narrowed portion. FIG. 9 is a schematic view of the capsule, FIG. 9 is a schematic view of the state in which the protrusion is removed, and FIG. 10 is a table showing the state from the insertion of the inspection capsule to the stop.

In this embodiment, the pipe 1 is detected by detecting a change in the frequency of the acoustic signal oscillated from the inspection capsule A.
The narrowing portion 14 in 2 is to be indexed.

That is, an acoustic signal having a constant frequency V0 is always transmitted from the inspection capsule A to be inserted into the pipe 12, and the acoustic signal is received by the microphone 17 arranged on the downstream side of the pipe 12.

In addition to being connected to the microphone 17, an external computing means (not shown) determines the position of the narrowed portion 14 from the change in the frequency V of the acoustic signal detected by the microphone 17.

That is, in FIG. 6, the inspection capsule A is used.
Flow velocity of U0 (m / sec), sound velocity in the fluid is C0 (m / sec)
), The frequency V (HZ) of the acoustic signal detected by the microphone 17 is V = C0.V0 / (C0-U0).

On the other hand, as shown in FIG. 8, the frequency V of the acoustic signal detected by the microphone 17 when the inspection capsule A is hooked on the narrowed portion 14 formed by the protrusion 13 is Since the movement of the inspection capsule A is stopped, V = V0.

Therefore, if the flow velocity U0 of the inspection capsule A in the pipe 12 is constant, the elapsed time t from when the inspection capsule A is put into the pipe 12 until V = V0 is measured. By doing so, the distance L from the position where the inspection capsule A is inserted to the squeezing position 14 can be calculated from L = t · U0.

Further, an explosive is provided in the capsule body 1 of the inspection capsule A, and after the inspection capsule A is stopped at the squeezed portion 14, the self-detonation is caused after a predetermined time elapses, as shown in FIG. Moreover, the protrusion 13 can be easily removed. As a result, the squeezed portion 14 can be maintained without replacing the pipe 12, and the handleability is good.

The self-destruction of the inspection capsule A may be controlled by an acoustic signal transmitted from the outer surface of the pipe 12.

Further, the present invention is not limited to the above-mentioned respective embodiments, and, for example, if the stylus 2 protruding from the capsule body 1 is housed in the capsule body 1 after a lapse of a predetermined time, the narrowed portion can be detected. After that, the inspection capsule A can be collected.

[0042]

As described above, according to the present invention,
Only by inserting the inspection capsule into the fluid in the pipe, the narrowed portion in the pipe can be easily detected, and the pipe to be replaced or repaired can be easily specified.

Further, since the inspection can be carried out with the fluid flowing in the pipe, it is not necessary to stop the plant or the like, the handling and workability are good, and the user's cost burden is reduced.

[Brief description of drawings]

1 to 6 show a first embodiment of the present invention.
Is a cross-sectional view of the inspection capsule being flown into the tube

[Fig. 2] External view of the inspection capsule

FIG. 3 is a cross-sectional view of a main part of an inspection capsule.

FIG. 4 is an IV-IV arrow view of FIG.

FIG. 5 is a circuit diagram of an acoustic signal generating means incorporated in an inspection capsule.

FIG. 6 is an explanatory view of a method for detecting the position of a narrowed portion.

7 and 8 show a second embodiment of the present invention, and FIG. 7 is a schematic view of an inspection capsule moving in a pipe.

FIG. 8 is a schematic view of an inspection capsule hooked on a narrowed portion.

FIG. 9 is a schematic view of a state in which the protrusion is removed.

FIG. 10 is a table showing a state from when the inspection capsule is put in until it is stopped.

[Explanation of symbols]

 2 ... Contact member 6 ... Acoustic signal generating means 12 ... Piping 14 ... Squeezing site 15, 16, 17 ... Signal detecting means A ... Inspection capsule

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[Procedure amendment]

[Submission date] March 19, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

Means for Solving the Problems] To achieve the above object pipe inspection device according to the present invention, the outer periphery of the test capsule can flow in a pipe, engaging freely plurality of contact members constriction site within a vessel In addition to the above, the inspection capsule has acoustic signal generating means built-in, and signal detecting means for detecting an acoustic signal from the acoustic signal generating means is provided outside the tube.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

An acoustic signal generator 6 as shown in FIG. 5 is built in the capsule body 1. An electrode plate 5 arranged on each of the conductive rubbers 4 is connected to an analog multiplexer 7 of the acoustic signal generator 6, and the analog multiplexer 7 is connected to a CPU 10 via an amplifier 8 and an A / D converter 9. Has been done. The analog multiplexer 7 selects and takes in the output signal from each electrode plate 5 at a predetermined timing in accordance with a command from the CPU 10.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

On the other hand, reference numeral 12 in FIG. 1 is piping for boilers, chemical plants, and the like, and 13 is a projection formed in the piping 12 due to rust, scratches or the like, or a projection formed by deposits. A narrowed portion 14 is formed in the pipe 12 by the portion 13.

Claims (1)

[Claims] 1. A plurality of contact members which can be hooked at a narrowed portion in the tube are provided on the outer periphery of the inspection capsule which can be distributed in the tube, and an acoustic signal generating means is built in the inspection capsule. An in-pipe inspection apparatus characterized in that signal detection means for detecting an acoustic signal from the acoustic signal generation means is provided outside.