JPH0258576B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for easily and efficiently locating water leaks that occur in water supply pipes etc. buried underground.

The above-mentioned water leaks not only cause a large loss of water resources, but also often cause inconvenience to water service users, so it is an important issue to quickly discover and repair the water leaks. To solve this problem, various devices for detecting water leaks have been proposed in the past, but it is extremely difficult to detect water leaks that occur in underground pipes at an early stage. For this reason, attempts are often made to discover the location of the water leak only after the water leak has been left unattended for a considerable period of time and the extent of the water leak has increased. Furthermore, even when a water leak has progressed, it is difficult to quickly identify the location of the leak, and the reality is that the location of the leak is discovered through inefficient work that involves trial and error and relies on the intuition of on-site workers. .

Various devices have been proposed in the past for locating water leaks, but these devices have not yielded satisfactory results. The reasons for this are: a. The sound of water leakage is weak in the early stages of water leakage; b. The sound quality of water leakage sound is similar to surrounding noise.
Point out that the water leakage sound is interfered with by noise, making it difficult to distinguish between the noise and the water leakage sound (therefore, the difficulty of discrimination cannot be alleviated even with band-pass processing, etc.). Can be done.

Conventionally, a device has been proposed that generates high-frequency sound waves between two fixed points on a pipe and detects the distance from the fixed point where the waveform is disturbed due to the presence of water leakage, but this method is complicated. It is not currently in practical use because it has a similar configuration.

The present invention improves the circumstances listed in a and b above,
The purpose of the method of the present invention is to raise the level of water leakage sound to above the noise level and to make the sound quality of water leakage sound completely different from noise. While blocking the water flow through the valve, water with pressurized gas is injected downstream of the valve to generate a flow of the injected water in the water supply pipe, and the gas separated from the injected water is A portable detection device on the ground detects the popping sound generated when water rapidly escapes from a leakage point, and the leakage point is discovered based on the position of the portable detection device.

When performing the above method of the present invention, the sounds generated at the water leakage point are "crackling", "pichi pichi", and "pop".
These are plosive sounds such as "pop" and "pop", and their frequencies are quite high.These sounds are impact sounds generated by the liquid hitting the pipe wall when gas and liquid are released alternately. This is a composite sound of this and the flow sound generated by the successive overflow of gas through the leak hole.

Whether the sound that occurs at a water leakage point is “cracking, popping,” “pop, popping,” or “pop” depends on the bubbles that form in the injected water. Although it depends on the size and the shape and size of the leak hole, in either case, the energy level of the generated sound is high and the sound quality is completely different from surrounding noise. These sounds are water hammer-like sounds that occur on a small scale.

It is desirable to use non-corrosive nitrogen gas as the gas mixed with the injected water.

An example of an apparatus for carrying out the method of the present invention is shown in the figure. In the following, the invention will be explained with reference to this figure.

In the figure, 1 is a water injection device, and 2 is a cart for moving this device 1. Gas cylinder 3 is on truck 2
(for example, a nitrogen gas cylinder), a water tank 4, a pressure pump 5, and a mixer 6 are mounted. The gas in the gas cylinder 3 is transferred to a pressure regulating valve 7 and a pipe line 8.
On the other hand, water in the water tank 4 is supplied to the mixer 6 via a pipe 9, a pressure pump 5, a valve 10, and a pipe 11.

12 is a valve on the delivery pipe 13 of the mixer 6, 16 is a water supply pipe buried under the path, and 17 is a rising branch pipe connected to the water supply pipe 16. The upper part of the rising branch pipe 17 is exposed above the ground. The delivery pipe 13 is connected to the riser pipe 17 via a flexible pipe 18.

Water produced in mixer 6 while adding pressurized gas is forced into water supply pipe 16 via delivery pipe 13, flexible pipe 18 and riser pipe 17.
19 is one of a series of valves provided on the water supply pipe 16, this one being upstream of the riser pipe 17.

When water mixed with pressurized gas is injected into the water supply pipe 16, the peculiar popping sound mentioned earlier is generated at the water leakage point 34, and the location of the popping sound, that is, the water leakage point, is detected by a portable detection device 22. Detected.

The detection device 22 consists of a detection rod 24 that is moved appropriately on the ground, and a waveform display and recording device mounted on a trolley 25. The detection rod 24 is provided with a microphone 23 that is applied to the ground and an amplifier 26 that amplifies input from the microphone. The amplifier 26 has a terminal connected to a headphone 28 (or earphone) as a water leakage sound listener via a cord 27, and a cord 2 to a water leakage sound modulator 30.
Terminals connected to each other via 9 are provided. Modulator 3
0 is connected to an oscillograph 31, and the waveform display of water leakage sound and its recording are performed by the oscillograph 31.

The water injected into the water supply pipe 16 is a two-phase medium containing a very large number of gas particles. As this material flows downstream, the gas is gradually separated, and the size of the gas particles increases accordingly. When the injected water reaches the leakage point, since the pressure outside the leakage point 34 is atmospheric pressure, a large number of gas particles quickly escape out of the pipe together with the water while imparting a large amount of dynamic energy. Since the airflow particles are intermittent, leakage water hits the pipe wall with an impact, causing the "crackling", "pichi pichi", and "bang pang" mentioned earlier. Plosive sounds such as "pop-pon" occur singly or in combination.

In many cases, the peculiar water leakage sound mentioned above is caused by headphone 2.
However, if the water supply pipe 16 is buried deep, even if the water leakage sound is unique, it may be difficult to hear with a listening device. The waveform display by the oscilloscope 31 is particularly effective in this case, and allows the location of the water leak to be detected easily and reliably.

The method and apparatus of the present invention described above injects a two-phase fluid consisting of water and pressurized gas in order to detect individual water leaks, and this water interacts with the water leak location to detect unique spots that occur. It detects sound.

In the past, research has focused on how to capture the fricative jetting sound (swooshing sound) caused by water leakage, but the present invention focuses on the medium flowing through water supply piping, This medium, regular water, temporarily replaces the previously mentioned two-phase medium and produces a leaking sound that has a high energy level and is easy to hear and distinguish.

The effects brought about by the present invention are that water leakage points can be discovered at an early stage, water leakage points can be detected accurately and wasteful excavation work can be avoided, and water leakage occurs within a relatively long section. The point is to make it easy to find the location.

Note that the present invention can also be applied to discovering the location of water leakage occurring in reinforced steel or steel-framed buildings.

[Brief explanation of drawings]

The drawing is an overall view of an apparatus for carrying out the water leak location detection method according to the present invention. 1...Water injection device, 2...Dolly, 3...Gas cylinder, 4...Water tank, 5...Pressure pump, 6
... Mixer, 7 ... Pressure regulating valve, 13 ... Sending pipe, 16 ... Water supply piping, 17 ... Rising branch pipe, 1
8... Flexible tube, 22... Detection device, 23
... Microphone, 24 ... Detection rod, 25 ... Amplifier, 28 ... Headphone, 30 ... Modulator, 3
1...Oscillograph.

Claims (1)

[Claims] 1 Close the valve on the water supply pipe to cut off the water flow passing through this valve, and at the same time inject water mixed with pressurized gas to the downstream side of the valve to generate a flow of the injected water in the water supply pipe. , a portable detection device on the ground detects the popping sound that occurs when the gas separated from the injected water rapidly escapes from the leak point, and the location of the water leak is discovered based on the position of the portable detection device. A method for finding leaks in water supply piping.