HK1126850B - Leakage detector - Google Patents

Description

Leak detection device

Technical Field

The present invention relates to a leakage detection device for detecting the presence or absence of leakage of a fluid such as water or gas flowing through a fluid pipe such as a water pipe or a gas pipe buried under the ground and a leakage position.

Background

Conventionally, as a device for detecting the presence or absence of leakage and the leakage position of a fluid such as water or gas flowing through a fluid pipe such as a water pipe or a gas pipe buried underground, an acoustic leakage detection device 81 is known, and as shown in fig. 8, the acoustic leakage detection device 81 is configured by a vibration detection device 82, a voltage amplification device 85, and a headphone 86, the vibration detection device 82 being configured by a pickup 83 and a wire 84 (see, for example, patent document 1).

Patent document 1: japanese laid-open patent publication No. 10-325778

In the case of detecting the presence or absence of water leakage in the water course pipe and the leakage position using this leakage detection device 81, as shown in fig. 9, the operator holds the voltage amplification device 85 at the waist with a strap, and attaches the headphone 86 to the head with the strap hanging down from the top of the head. Then, the pickup 83 is placed on the ground surface by holding the appropriate portion of the wire 84 with one hand.

When the voltage amplifier 85 is turned ON, the water leakage sound, which is minute vibration generated at the water leakage point of the water pipe and propagated underground, is captured by the pickup 83 mounted ON the ground surface and converted into an electric signal. Then, the voltage is amplified by the voltage amplifier 85 until the level reaches an audible level, and the sound is output from the headphone 86.

The operator places the pickup 83 on the floor surface at intervals of 0.5 to 1.0mm along the water channel, and listens to the output sound from the headphone 86. Then, whether water leakage exists or not is judged according to the strength, the height and the like of the water leakage, and when the level of the output sound reaches a maximum value, a water leakage point exists in the water channel pipeline right below the water leakage point.

Here, the water leakage sound generated at the water leakage point of the waterway pipe propagates underground until reaching the ground surface, and is attenuated to a very small vibration. Therefore, the water leakage detection operation as described above is usually performed at night when traffic noise due to automobiles, pedestrians, and the like, industrial noise due to factories, construction sites, and the like, and living noise due to in-store equipment, vending machines, and the like become very small.

Disclosure of Invention

Problems to be solved by the invention

However, even at night, traffic noise due to automobiles, pedestrians, and the like may actually occur temporarily, and life noise due to in-store equipment, vending machines, and the like, which are in business late at night, may occur stably even though it is small. In this case, in the conventional leak detection device 81, since the pickup 83 captures the noise and the output sound from the headphone 86 is mixed as the noise, it is difficult to accurately and reliably detect the presence or absence of the leak and the leak position.

In addition, in the leak detection operation using the conventional leak detection device 81, an operator listens to the output sound from the headphone 86, determines the presence or absence of a leak based on the minute intensity, level, and the like, and determines a leak point when the minute level becomes maximum.

The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a leak detection device capable of accurately and reliably detecting the presence or absence of a leak in an embedded fluid pipe and a leak position even when traffic noise caused by a car, a pedestrian, or the like is temporarily generated and life noise caused by in-store equipment, an automatic vending machine, or the like which is in late-night business is stably generated.

It is another object of the present invention to provide a leak detection device that can accurately and reliably detect the presence or absence of a leak in a buried fluid pipeline and the location of the leak, even by a person who is not highly skilled in the leak detection operation.

Means for solving the problems

In order to achieve the above object, a leak detection device according to the present invention is characterized by comprising: a vibration detection device having a pickup in which a piezoelectric element is built; a detection device main body in which a voltage amplifier that voltage-amplifies an output signal and a plurality of types of noise removing units that remove noise from the output signal are built; and a headset.

According to this configuration, the presence or absence of a leak in the buried fluid pipeline and the location of the leak can be accurately and reliably detected because the optimum noise removing means can be appropriately selected in consideration of the noise generated in the environment where leak detection is performed.

Preferably, the plurality of types of noise removing means can be applied in an appropriate combination, and the setting conditions can be changed.

Preferably, the probe main body includes a display device for displaying the detected vibroacoustic data on a predetermined screen.

According to this configuration, not only the vibration detection level can be heard, but also the numerical display and the graphic display can be visualized, and therefore, even a person who is not highly skilled in the leak detection operation can accurately and reliably detect the presence or absence of a leak in the buried fluid pipe and the leak position.

Preferably, the vibration detection device includes a noise absorbing member made of a rubber block attached to the signal output line.

If a gripping member for gripping the vibration detection device is provided and an audible switch is disposed on the gripping member, the operator can press the audible switch in a portable manner, and operability is further improved.

Drawings

Fig. 1 is a perspective view showing the structure of a leak detection device of the present invention.

Fig. 2 is a front view of the vibration detection device and the gripping member.

Fig. 3 is a sectional view of the noise absorbing member.

Fig. 4 is (a) a front view, (B) a left side view, (C) a top view, and (D) a right side view of the detecting device main body.

Fig. 5 is a schematic configuration diagram of the inside of the probe apparatus main body.

Fig. 6 is a schematic configuration diagram of the delay processing noise removing unit.

Fig. 7 is an explanatory diagram showing a screen displayed on the display device of the probe apparatus main body.

Fig. 8 is a schematic configuration diagram of a conventional leak detector.

Fig. 9 is an explanatory diagram of a case where leak detection is performed by an acoustic leak detection device.

Description of reference numerals

1: a leak detection device; 2: a vibration detection device; 3: a holding member; 4: a probe main body; 5: a headset; 6: a pickup; 7: a wire; 8: a noise absorbing member; 13: an audible switch; 15: a display device; 33: a band-pass filter; 34: comb filters (comb filters); 35: a delay processing noise removing unit.

Detailed Description

The preferred embodiments of the leak detector according to the present invention will be described in detail below with reference to the accompanying drawings.

Fig. 1 is a perspective view showing the structure of a leak detector according to the present invention, fig. 2 is a front view of a vibration detector and a grip member, fig. 3 is a sectional view of a noise absorbing member, fig. 4 is (a) a front view, (B) a left side view, (C) a plan view, and (D) a right side view of a detector main body.

As shown in fig. 1, a leak detection device 1 of the present invention is composed of a vibration detection device 2, a grip member 3, a detection device body 4, and a headphone 5.

As shown in fig. 1 and 2, the vibration detection device 2 is composed of a pickup 6, a wire 7, and a noise absorbing member 8.

As shown in fig. 2, the pickup 6 includes a mounting portion 9, a main body portion 10, and a connecting portion 11, and the mounting portion 9 is formed by bending a metal plate material to form a plurality of legs. The main body 10 houses a metal vibrator and a piezoelectric element fixed to the vibrator and is covered with a rubber cover, and the connecting portion 11 houses a connector and is covered with a rubber cover.

As shown in fig. 2, the wire 7 is formed by covering a lead wire connected to a harness of the piezoelectric element with a protective material made of polyvinyl chloride, winding the lead wire around the lower portion of the wire 7 to form a loop 7a, and binding the wire portion overlapping the loop 7a with binding members 12 and 12 made of rubber.

As shown in fig. 2 and 3, the noise absorbing member 8 is a spherical rubber block, and a substantially U-shaped wire insertion passage 8a having an inner diameter substantially equal to the outer diameter of the wire 7 is formed inside the noise absorbing member 8.

The lower end portion of the wire 7 below the loop portion 7a is inserted into the wire insertion path 8a and is attached to the vicinity of the pickup 6 of the wire 7.

In the vibration detecting device 2, the wire 7 is in an unstable state in the air when the leak detecting operation is performed, but since the ring portion 7a is formed at the lower portion of the wire 7 and the overlapped wire portions are bound by the binding members 12 and 12, minute vibration is less generated in the horizontal direction even if wind is applied to the lower portion of the wire 7, and minute vibration is less generated in the vertical direction even if the hand is moved. Therefore, frictional wind noise and frictional sound are hardly generated in the wire 7.

Further, since the noise absorbing member 8, which is a rubber block, is attached near the pickup 6 of the wire 7, even when wind noise and frictional noise are generated in the wire 7, the noise absorbing member 8 absorbs minute vibration by the action of the material itself and the action of the inertial mass, and thus noise due to wind noise and frictional noise can be effectively removed.

Further, since the wire 7 is inserted into the substantially U-shaped wire insertion path 8a, and the wire 7 is bent largely at least at two positions to harden the protective material of the wire 7 and improve the vibration absorption characteristics, it is possible to absorb minute vibrations in the horizontal direction and the vertical direction at these bent portions and effectively remove noise due to wind noise and frictional noise.

As shown in fig. 1 and 2, the holding member 3 has a prism shape, and one end of the wire 7 is connected to a front end portion of a lower surface of the housing by a rubber sleeve protruding downward, and the wire 14 is connected to a rear portion by a rubber sleeve protruding rearward.

Further, an audible switch 13 is disposed on the front side portion of the lower surface of the housing, and the operator can press the audible switch 13 with his index finger or the like while holding the holding member 3.

As described above, if the audible switch 13 is disposed on the front side portion of the lower surface of the gripping member 3 in advance, the operator can operate the audible switch 13 while gripping the gripping member 3 at the time of the leak detection operation, and it is not necessary to move the probe apparatus body 4 with one hand to confirm and press the audible switches 23 disposed on the probe apparatus body 4 one by one, which is very good in operability.

As shown in fig. 1 and 4, the detector main body 4 is provided with a display device 15 formed of an LCD at the center of the upper surface, and a filter high frequency setting key 16, a filter low frequency setting key 17, a comb filter setting key 18, a delay processing noise removal mode setting key 19, a display screen switching key 20, a data storage key 21, and a backlight key 22 are provided around the display device 15.

An audible switch 23 is disposed at the upper right end of the upper surface, and a sensitivity setting dial 24 is disposed at the upper left end of the upper surface.

A power switch 25 and a communication port 26 are disposed on the left side surface of the probe device body 4, and a vibration detection device connection connector 27 and a headphone jack 28 are disposed on the right side surface.

Further, locking groove portions 29, 29 for locking the lower end portions of the belts suspending the probe device body 4 are formed at the central upper end portions of the left side surface portion and the right side surface portion, and locking members 30, 30 for passing the belts holding the probe device body 4 are fixedly attached to both rear side portions.

As shown in fig. 5 and 6, the probe apparatus body 4 incorporates a voltage amplifier 31, an a/D converter 32, various noise removing units, a D/a converter 36, and a voltage amplifier 37.

In the present embodiment, the band-pass filter 33, the comb filter 34, and the delay processing noise removing unit 35 are employed as the various noise removing units.

The band-pass filter 33 passes only frequency components in a specific range, and attenuates frequency components other than the frequency components.

The passband of the bandpass filter 33 can be set appropriately by operating the filter high frequency setting key 16 and the filter low frequency setting key 17.

In the probe main body 4, high-frequency frequencies of 400, 600, 800, 1200, 2200Hz can be set by the filter high-frequency setting key 16, and low-frequency frequencies of 0, 100, 200, 400Hz can be set by the filter low-frequency setting key 17.

For example, if a high frequency of 800Hz is set by the filter high frequency setting key 16 and a low frequency of 200Hz is set by the filter low frequency setting key 17, the band pass filter 33 having a pass band of 200 to 800Hz can be set.

The comb filter 34 attenuates frequency components at specific frequency intervals and passes frequency components other than the attenuated frequency components.

The attenuation band of comb filter 34 can be appropriately set by operating comb filter setting key 18.

In the probe apparatus main body 4, the fundamental frequency can be set to 50Hz or 60Hz by the comb filter setting key 18, and the frequency components up to the 5 th harmonic can be attenuated for each harmonic.

For example, if the fundamental frequency is set to 50Hz by the comb filter setting key 18, the comb filter 34 that attenuates frequency components of 50, 100, 150, 200, and 250Hz can be set.

The delay processing noise removing unit 35 converts a signal in which leakage noise and external noise are mixed into a signal composed of frequency components, compares power between the frequency components of the signal at different sampling times, selects a frequency component having smaller power in all frequency bands, and generates a signal from the frequency component, from which the external noise is removed.

The delay time, which is the difference in sampling timing, can be set appropriately by operating the delay processing noise removal mode setting key 19.

In the probe apparatus main body 4, the noise removal mode setting key 19 can be set to LEVEL 1 (delay time 0.2s), LEVEL 2 (delay time 1.0s), and LEVEL 3 (delay time 3.0s) by the delay process.

For example, if LEVEL 2 is selected by the delay processing noise removal mode setting key 19, signals whose sampling times differ by 1.0s are compared, and a frequency component having a smaller power is selected in all frequency band ranges, so that a signal from which extraneous noise is removed can be generated.

Specifically, as shown in fig. 6, the delay processing noise removing unit 35 is constituted by: a fast fourier transform processing unit 38 that converts the signal into frequency components; a signal holding unit 39 that holds a signal as a frequency component and generates a delayed signal; a signal determination unit 40 that compares frequency components of signals at different sampling times to determine the power level; a switching unit 41 connected to an appropriate terminal and selecting a signal as an appropriate frequency component; and a fast inverse fourier transform processing unit 42 that generates a signal from the selected frequency component.

Since traffic noise caused by automobiles, pedestrians, and the like is temporarily generated while leakage sound of water, gas, and the like is stably generated, it is considered that external noise is generated at a certain time when the power of a specific frequency component of an output signal is large at the time. Thus, if the signal at the time when the power of the specific frequency component is small is selected by the delay processing noise removing unit 35, it can be said that an output signal with less extraneous noise can be extracted.

When the power switch 25 is pressed, the level display screen 43 is displayed 1 to 2 seconds after the initial screen is displayed on the display device 15, as shown in fig. 7.

Then, as shown in fig. 7, each time the display screen switching key 20 is pressed, the display screens are switched in order as the level display screen 43, the file list display screen 44, and the graphic display screen 45.

In addition, when the screen of the display device 15 cannot be seen clearly at night or the like, if the backlight key 22 is pressed, the backlight of the display device 15 can be turned on, and the screen can be seen reliably.

The minimum shake detection level value in the sampled data at the time of listening is displayed on the level display screen 43. The minimum vibration detection level value is displayed as a relative numerical value of 000 to 999 such as "MIN 999".

In addition, the change in the vibration detection level is visualized by the auditory level bar 46, and the change in the auditory level bar 46 is displayed as relative numerical values of 00 to 99 as "99".

The file No., the minimum vibration detection level value, the year, month, day, and time are displayed on the file list display screen 44 as file data that can be stored in a predetermined file in an internal memory (not shown).

The file No. and its minimum shake detection level value are numerically displayed on the graphic display screen 45, and the minimum shake detection level value corresponding to the file No. is displayed with the graphic 47 for the selected file data of 10 dots.

When the data saving key 21 is pressed on the level display screen 43 in a state where the audible switch 13 of the gripping member 3 or the audible switch 23 of the probe apparatus main body 4 is pressed and turned on, the file No. of the saving destination on the screen is turned on.

When the audio switch 13 or the audio switch 23 is turned OFF (OFF) by being pressed, the minimum vibration detection level value during detection is stored in a predetermined file in the internal memory, and the file No. of the storage destination is turned OFF from the screen.

In addition, if the connector of the cable of the personal computer is connected to the communication port 26 of the probe apparatus main body 4, the file data stored in the internal memory of the probe apparatus main body 4 is transmitted in accordance with a data transmission command from the personal computer.

As shown in fig. 1, the headphone 5 has left and right ear pads 49, 50 disposed at both ends of a headband 48, and a cord 51 is led out from one of the ear pads 49.

Next, a case where the method of using and the operation of the leak detection device 1 according to the present invention are applied to detection of water leakage in a water channel pipe buried under the ground will be described.

First, the vibration detection device 2, the grip member 3, and the headphone 5 are connected to the probe device body 4, and the power switch 25 of the probe device body 4 is pressed to turn on the power. Then, the filter high frequency setting key 16, the filter low frequency setting key 17, the comb filter setting key 18, and the delay processing noise removal mode setting key 19 are operated to appropriately select and set an optimum noise removal means in an environment where leak detection is performed.

Next, the headphone 5 is attached to the head, the detection apparatus body 4 is hung from the head with a band, and is held at the waist with the band. Then, the holding member 3 is held by one hand, the pickup 6 is placed on the floor surface in which the water pipe is buried, the acoustic switch 13 of the holding member 3 or the acoustic switch 23 of the probe main body 4 is pressed and turned on, and the detection signal is output from the pickup 6.

The leakage sound detected by the pickup 6 is signal-amplified by a voltage amplifier 31 in the detection device main body 4, and after the noise is removed by predetermined filters 33 and 34 and a delay processing noise removing unit 35 which are appropriately selected and set, the signal is output to the headphone 5 as vibration sound.

The operator listens to the level of the vibration sound outputted from the headphones 5, moves along the waterway pipe on the floor, places the pickup 6 on the floor surface at appropriate intervals, and continues the operation of listening to the level of the vibration sound outputted.

Then, whether or not water leakage occurs in the water pipe is determined based on the intensity and level of the output vibration sound, and if it is determined that water leakage has occurred, a point where the level of the vibration sound becomes maximum is searched for, and it is determined that a water leakage point of the water pipe is located immediately below the point.

When the power switch 25 is pressed, a predetermined screen is displayed on the screen of the display device 15, the minimum vibration detection level value in the sampling data at the time of listening is displayed, and the change of the vibration detection level is visualized by the listening level bar 46. The file No., the minimum vibration detection level value, the year, month, day, and time are displayed as file data, and the minimum vibration detection level value corresponding to the file No. is displayed on the graph 47.

As described above, in the leak detection device 1 of the present invention, not only the sound but also the numerical display and the graphic display can be visualized in response to the vibration detection level, and therefore, even a person who is not highly skilled in the leak detection operation can accurately and reliably detect the presence or absence of a leak in the buried fluid pipeline and the leak position. Further, even a person skilled in the leak detection operation can perform detection more accurately and reliably.

According to the leak detection device 1 of the present invention, when stable living noise having a predetermined frequency is superimposed on various in-store equipment, vending machines, and the like which are open at night, temporary traffic noise caused by automobiles, pedestrians, and the like, and irregular noise such as barking noise, it is possible to remove noise and reliably capture leak sound by applying all of the band-pass filter 33, the comb filter 34, and the delay processing noise removal unit 35.

In addition, when temporary traffic noise caused by a car, a pedestrian, or the like, and irregular noise such as a bark are superimposed, the bandpass filter 33 and the delay processing noise removing unit 35 are applied to remove the noise and reliably capture leakage noise.

When the noise is relatively small in a suburban area or the like, the application of only the band-pass filter 33 can remove the noise and reliably capture the leakage sound.

As described above, according to the leak detection apparatus 1 of the present invention, it is possible to appropriately select and set the optimum noise removing means in consideration of the type of noise generated in the environment where leak detection is performed, and therefore it is possible to accurately and reliably detect the presence or absence of a leak in an embedded fluid pipeline and the location of the leak.

Claims (4)

1. A leak detection device comprising: a vibration detection device having a pickup in which a piezoelectric element is built; a detection device main body in which a voltage amplifier that voltage-amplifies an output signal and a plurality of types of noise removing units that remove noise from the output signal are built; and a headset;

wherein the noise removing means comprises a band-pass filter, a comb filter, and a delay processing noise removing means;

wherein the band-pass filter passes only frequency components in a specific range and attenuates frequency components other than the specific range, and the high frequency and the low frequency of the passband can be appropriately set by operating a setting key,

the comb filter attenuates frequency components at specific frequency intervals, allows other frequency components to pass through, and can set a fundamental frequency by operating a set key to attenuate frequency components up to a predetermined harmonic,

the delay processing noise removing means converts a signal in which leakage noise and external noise are mixed into a signal composed of frequency components, compares powers between the frequency components of the signal at different sampling timings, selects a frequency component having a smaller power in all frequency bands, generates a signal from which the external noise is removed from the frequency component having the smaller power, and can appropriately set a delay time, which is a difference in sampling timings by operating a set key,

when leak detection is performed, the band-pass filter, the comb filter, and the delay processing noise removing unit can be selected and set in an appropriate combination.

2. The leak detection apparatus according to claim 1,

the probe main body includes a display device for displaying the detected vibration sound data on a predetermined screen, and the display device switches a display screen to a level display screen, a file list display screen, and a graphic display screen in this order.

3. The leak detection apparatus according to claim 1,

the vibration detecting device is configured such that a ring portion is formed by winding a signal output line, the ring portion is bound by a rubber binding member, and a noise absorbing member in the form of a rubber block is attached to a lower end portion of the signal output line.

4. The leak detection apparatus according to claim 1,

a gripping member for gripping the vibration detection device is provided, and an audible switch is disposed on the gripping member.