JPS58208636A - Detecting device for position of leakage from piping such as leakage of water - Google Patents

Abstract

PURPOSE:To improve the accuracy of measurement of a position of water leakage by measuring actually the value of either one of the speed of propagation of vibration of a piping to be measured or the length of the pipeline thereof with the value of the other made known, and by using a calibrated value of the length of the pipeline or the speed of propagation of vibration. CONSTITUTION:The titled detecting device is provided with first and second sensors 2 and 3 provided in the longitudinal direction of a pipe 1 to be measured, a comparator 8 delivering a trigger signal only when it receives a sensing signal delivered from the sensor 2 when a reference voltage set beforehand is exceeded, an A/D converter 6, and a correlation wave memory 10 accumulating digital signals of digital data sequentially according to the trigger signal and recording the n-th data corresponding to the maximum amplitude value from the first data starting from the trigger signal. The number N of the recorded data from the first to the n-th is detected by CPU12, and the time TD of delay of amplitude from the sensor 2 to the sensor 3 and the period TS of a sampling pulse are determined to have the relationship of TD=TSXN based on a known value of the speed of propagation of amplitude or the length of a pipeline, and on a calibrated value in conformity with the actual state at the point of time of measurement.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for detecting the location of water leaks from piping by using a correlation method to sense and detect locations where water, oil, scum, etc. are leaking from specific positions of piping. It is.

Current water leakage detection work uses listening rods and amplifiers inserted into the ground to listen directly to the sound of water leaks that propagate underground, and predicts the location of water leaks based on the sound volume, tone, etc. However, this method requires a high level of skill and requires nighttime measurements with little noise. In addition, buildings, rivers,
It is practically impossible to locate water leaks in pipes installed under obstacles such as asphalt roads. In order to overcome these difficulties, measurements of the location of water leakage points, for example, have come to be carried out based on the theory of correlation functions. However, the devices currently in use are capable of accurately measuring the location of water leaks when the propagation velocity of water leak sound in the pipe and the length of the pipe are accurately known, and the length of the pipe is unclear due to incomplete piping diagrams. However, if the propagation velocity changes over time due to corrosion and deterioration of the pipe, the error in the measurement position increases. In addition, after measuring the correlation function, the peak point of the correlation value was read visually and the leak position was obtained by hand calculation using a calculator, etc., which had the disadvantage that on-site measurement was complicated and incorrect results were calculated.

In order to solve these shortcomings, the present inventor has determined that either the vibration propagation velocity or the pipe length of the piping to be measured is known, and the other value is actually measured to determine the pipe length or vibration propagation velocity. This invention provides a device for detecting the position of water leaks from piping, which is intended to measure the position of water leaks with high precision using calibration values, and will be described in detail below with reference to the drawings.

The drawing is a schematic diagram showing an embodiment of the present invention. First, as shown in the diagram, fire hydrants and water stop hydrants.

A vibration detection sensor 2 and a sensor 3 are respectively fixedly mounted in the longitudinal axis direction of a pipe 1 to be measured, separated by an appropriate distance, from which water leakage or the like is to be detected using a water meter or the like. 2
and 3 correspond to the first and second vibration detection elements that detect the first and 20th sensing signals. In this state, apply an impact with a hammer to the pipe at the 1 location where the sensor 2 is installed. In this way, vibrations are transmitted to sensor 2 without any time delay, and vibrations are transmitted to sensor 3 with a certain time delay of 1"L. Sensing signal output from each sensor is transmitted to the corresponding amplifier 4. , @5VC is input and amplified.The first sensing signal from the amplifier 4 is input to the comparator 8,
When the voltage exceeds a preset reference voltage, a pulse is output as a trigger signal. - The second sensing signal from the amplifier 5 is inputted to the A/D converter 7, converted into digital data by a sampling pulse cycle at fixed time intervals, and outputted. If the correlation/wave memory is set to wave memory operation by the control circuit 9, the comparator 8
The digital data from the A/D converter 7 is sequentially recorded in the memory by the trigger pulse. When the recording of the specified number of data, that is, the recording of the nth data from the first data based on the trigger signal to the maximum amplitude value of the second sensing signal, is completed, according to the program stored in ROMIIVc. The CPU 12 detects the number N of points from the start of the recorded data to the peak position,
The delay time TD from the sensor 2 to the sensor 31 is determined from the sampling period Ts as TD=TSXN.

Specifically, TD is displayed on the CRT 13. Therefore, if the pipe propagation velocity V is known, the pipe length is L = 'l''p
If the pipe length is known, the pipe propagation velocity V is determined as V = L/TO.
13 [Displayed. ? 71n by the control circuit 9.
If the wave memory lo is set to a correlation calculation operation (that is, an operation that performs multiplication and integration using a time delay as a parameter), for example, water leakage sound detected by the sensors 2 and 3 will be detected by the V converter 6. A correlation function is calculated using the correlation/wave memo January 0 via the A/D converter 7. When the calculation is completed, the peak point of the correlation value is automatically detected by the CPU 12 according to the ROM II program, and the difference in time between the arrival time of the vibration signal generated from the water leak point to the sensor 2 and the sensor 3 is determined. -Displayed. RO in advance at 7'K
The reference point (for example, sensor 2) is determined by the CPU 12 according to the parameters such as the pipe type, pipe diameter, pipe length, and pipe structure set in the MII and the calculation program stored in the ROMII.
The distance to the water leakage point is displayed on the CRT 13.

In this case, it may be output to the printer 14.

As explained above, the pipe length or pipe propagation velocity, which is an important parameter necessary for calculating the leak location, is calibrated using actual measured values.
Based on this calibration value, it has the advantage of allowing highly accurate position calculations because it matches the actual condition of the piping at the time of measurement. In addition, since measurements can be performed automatically from the start of correlation calculation to the determination of the water leak location, accurate results can be easily obtained.

[Brief explanation of the drawing]

The figure is a schematic configuration diagram showing an embodiment of the invention. 1... Pipe to be measured, 2... Sensor, 3... Sensor,
4... Amplifier, 5... Amplifier, 6... A/D converter, 7... A/D converter, 8... Comparator, 9
...Control circuit. 10...Correlation/wave memory circuit, 11...RO
M, 12...CPU, 13...CRT, 14/Printer Patent applicant Japan Radio Co., Ltd.

Claims (1)

[Claims] a first vibration detection element that detects a first sensing signal corresponding to the imaging caused by a strike S applied to a fixed position of the pipe to be measured; For photographing a specific position in the longitudinal axis direction of the pipe to be measured that occurs at a certain point in time? A second fast-moving detection element for detecting a corresponding second sensing signal is arranged on the same longitudinal axis of the tube to be measured, and the first sensing signal and a preset reference voltage are applied. a comparator that outputs a trigger signal only when a first sensing signal exceeding the reference voltage arrives; An A/A that outputs digital data sequentially converted into digital signals using
D i converter, each digital signal of the digital data is sequentially accumulated by the trigger signal, and the data is stored from the first data to the n-th data corresponding to the maximum amplitude value based on the trigger signal. The CPU detects the number N of recorded data from the first vibration detection element to the second vibration detection element.
The amplitude delay time TD up to the vibration detection element and the sampling pulse period Ts have a relationship of TD=T''s 1. An apparatus for detecting the position of a leak from a pipe, such as a water leak, based on a pipe length or a vibration propagation velocity having a calibration value.