JPH06100454B2 - Failure point direction determination device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a failure point direction determination device for detecting the position of leakage of gas, powder, or liquid from a transport pipe.

(Prior Art) In order to embody the description, an underground leak from a water pipe will be taken as an example below. The leak detection method is a hearing method that depends on human hearing, a correlation method that calculates the correlation between signals from two distant points, and the phase difference of the signals estimates the position from the propagation velocity. A time-integration type leak detection device based on the principle that the difference between transientness such as noise and continuity of leaks is the basic principle (JP-A-60
No. 209117) is known. In the audiophonic method, a listener carefully estimates the water leakage position from the ground by relying on the strength and tone of the sound, but the estimated position varies widely. Although the correlation method is a scientific method, since the propagation velocity of sound in the pipeline varies depending on the pipeline material, it is a condition that the pipeline material and the pipeline length are accurately known. In addition, the position estimation error is about ± 1 m due to the fluctuation of the propagation velocity due to the influence of the joint, the sluice valve, the fire hydrant, the branch point, etc. existing in the middle of the pipeline. Further, the time-integration type water leak detection device is intended for automatic water leak detection within a few 10 m of the surrounding area, and the position of the water leak cannot be specified. In this way, since position errors are unavoidable, it is often impossible to detect water leakage when excavating a buried pipe. Is repeatedly listening to the sound from the exposed pipe. Further, there is a water leakage detection device with a direction discrimination function proposed by the inventor (Japanese Utility Model Laid-Open No. 57-120228), which is originally designed for a pipe material person to discover water leakage in a known pipe line. , It is intended to be fixedly installed and cannot be applied to pipelines of any material.

(Problems to be Solved by the Invention) The present invention has been made in view of these problems.
(EN) Provided is a failure point direction determination device capable of determining in which direction the water leakage position of a water pipe of various materials is in a stand device.

[Structure of Invention]

(Means for Solving the Problem) According to the present invention, two detectors for detecting vibration of a pipe wall are provided, and a weight for absorbing high frequency vibration is attached in the middle of the detector to detect the direction of a leak position of a vibration source. Is to determine.

(Operation) A typical example of vibration due to water leakage is an elastic wave propagating in a pipe wall and water in the pipe. That is, a change in particle density due to particle movement of the elastic body propagates as a compressional wave in the length direction. The amplitude of this elastic wave is attenuated as the distance from the vibration source increases due to the work reflected by the discontinuity of the transmission impedance in the middle of transmission and the work consumed by the particle motion. It is known that the degree of this attenuation is generally proportional to the vibration frequency.

By the way, the vibration generated by water leakage is several tens of Hz to several tens of kHz.
It is known to have a frequency band of z. Therefore,
As the propagation distance becomes longer, the decrease in the high frequency component exceeds the decrease in the low frequency component, and the average frequency decreases. on the other hand,
Since the work amount is proportional to the mass, the attenuation becomes large by mounting a mass point (weight) having a large mass in the propagation path of the vibration wave. As a result, the decrease in average frequency becomes remarkable.

(Example) Next, an example of the present invention will be described. FIG. 1 is a configuration diagram illustrating an implementation state of a failure point direction determination device. Ten
Is a water pipe uncovered, and 1 and 2 are vibration detectors mounted on the water pipe 10. Although not shown, it is desirable to fix the vibration detector to the water pipe with an appropriate jig. In the case of a steel pipe, workability is improved by mounting a permanent magnet below the vibration detector. The counters 3 and 4 count the number of AC waves after the output signals of the vibration detectors 1 and 2 are amplified and noise-cut as necessary, respectively,
Counting is started and ended based on the start and stop commands from the synchronizer 5. That is, the simultaneous signals are counted together with the counters 3 and 4. 6 is a weight, and 7 is a jig for fixing the weight 6 to the water pipe. Now, assuming that water is leaking from the point A, the vibration wave propagates in the direction of the arrow, and the number C2 of waves detected by the vibration detector 2 and measured by the counter 4 is the count detected by the vibration detector 1. It becomes larger than the number of waves C1 measured by the device 3. Conversely, if there is water leakage at point B, C1> C2. That is, there is water leakage on the side of the vibration detector having the larger counter value.

FIG. 2 shows another embodiment in which a reversible counter 8 is used instead of two detectors. For example, when the input terminal 81 is an addition input and the input terminal 82 is a subtraction input, the reversible counter is shown. If the value of 8 is positive, the leak is on the B point side, and if it is negative, it is on the A point side.

〔The invention's effect〕

As described above, according to the present invention, since the values of the counters are compared regardless of the type of pipe, the direction of the leak position in the ground can be easily known.

[Brief description of drawings]

FIG. 1 is a block diagram of a discriminating apparatus showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an embodiment of another embodiment. 1,2 …… Vibration sensor, 3,4 …… Counter 5 …… Synchronizer, 6 …… Weight 7 …… Weight fixing jig, 8 …… Reversible counter 10 …… Water pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Haga 817 Shimohirotani, Kawagoe City, Saitama 23 Examiner Masayuki Mori (56) References JP-A-60-209117 (JP, A) Actual exploitation Sho-57-120228 (JP, U)

Claims (1)

[Claims] 1. A pair of vibration detectors for detecting a vibration of a pipe wall and converting it into an electric signal, a weight fixed in the middle of these two sets of vibration detectors, and an alternating current of the two sets of vibration detectors. A fault point direction discriminating device comprising a synchronizing device for discriminating the direction of a fault point by comparing the wave numbers of signals.