BACKGROUND

1. Technical Field

This disclosure relates to detection systems and detection methods, and, more particularly, to a detection system and a detection method that apply to sound waves.

2. Description of Related Art

The pipeline required for living or industrial use is complex, for example, a natural gas pipeline of 35,000 kilometers long and an oil pipeline of 4,060 kilometers long are distributed in Taiwan. A gas pipeline of at least 3.5 million kilometers long is distributed in the world, and has aged for more than 40 years. The aged pipeline is badly corroded and significantly degraded, and causes accidents frequently.

In recent years, industrial safety accidents related to industrial pipeline occur mainly due to surface defects formed by external forces and/or material degradation of the industrial pipeline. Polluted environment also erodes the pipeline and forms fissures or even thins the pipeline wall structure. As a result, holes and fissures appear. If such holes and fissures can be detected in time, accidents can be prevented.

In general detecting methods, when the pipeline is cracked, the pressure therein will be released suddenly. And then a resonant sound wave will be generated passively, which can be detected at any position of the pipeline, in order to know where the crack appears. However, such passively generated resonant sound wave does not have enough strength and is likely interfered by noises, and instrument can hardly detect the resonant sound wave. In some occasions, the pressure in the pipeline is too small to actuate any resonant sound wave, and, of course, the instrument cannot detect any resonant sound wave, either. The general method of receiving the resonant sound wave passively is applied to liquid pipeline only, and cannot be applied to a gas pipeline (e.g., a natural gas pipeline).

Hence, some manufacturers try to solve the drawbacks of the method of receiving the resonant sound wave passively. A sound emitter provides a sound of a global bandwidth (i.e., at a frequency of 0-∞ Hz) into a pipeline. A resonant sound wave will be actuated if the frequency in the bandwidth is equal to the resonant frequency of the liquid in the pipeline. A plurality of signal receivers can be disposed on the pipeline to detect where the defects are formed on the pipeline.

However, for a long-distance pipeline the energy of the sound emitted by the sound emitter may be very large, and the sound emitter has to consume a lot of power and volume of equipment is large.

Moreover, in some cases, there are too many frequencies, i.e., the global bandwidth, that have to be detected, and too many signal data that have to be analyzed and processed. Therefore, in this case the determining and processing speed is low, where the positions of defects cannot be known in real time. And the detection accuracy is poor (e.g., the position determining error is more than ±50 meters). Accordingly, a large area of road has to be dug, which brings inconvenience to people walking or driving on the road.

Furthermore, in some cases, the pipeline has to be disposed with a plurality of signal receivers on various positions thereof, and has to modulate the energy of sounds emitted by the sound emitter, to ensure the pipeline can receive the sound wave anywhere, even at a position where the pipeline is bent. Accordingly, a great number of signal receivers have to be used, and a great area of road has to be dug in order for these signal receivers to be disposed on the pipeline, which increases the cost of the detection process significantly.

Therefore, how to overcome the drawbacks of the cases aforementioned is becoming one urgent issue in the art.

SUMMARY

In view of the abovementioned drawbacks, the present disclosure provides a detection system for detecting a defect of a target object that has an accommodating space and first and second ports on the accommodating space. The detection system comprises: a sound source device disposed at the first port and configured for providing and inputting a sound through the first port into the accommodating space to generate a resonant sound wave; a signal receiver disposed at the second port; and a database configured for storing reference information derived from simulation of a signal generated after the resonant sound wave is received by the signal receiver. The reference information comprises first data having characteristics of the resonant sound wave and data having features of an imaginary defect formed on the target object. The features of the imaginary defect correspond to the characteristics of the resonant sound wave. The signal receiver is configured for receiving the resonant sound wave to obtain target information and transmitting the target information to the database, and the target information comprises second data having characteristics of the resonant sound wave when the target object has a real defect, and features of the real defect corresponding to the second data are derived from the features of the imaginary defect corresponding to the first data, by comparing the target information with the reference information.

The present disclosure further provides a detection method, comprising: providing a target object having an accommodating space and a first port and a second port on the accommodating space, and disposing a sound source device at the first port and a signal receiver at the second port, respectively; enabling the sound source device to input a sound via the first port into the accommodating space to generate a resonant sound wave; simulating a signal generated when the resonant sound wave is received by the signal receiver and regarding the signal as reference information, wherein the reference information comprises first data having characteristics of the resonant sound wave and data having features of an imaginary defect formed on the target object, and the features of the imaginary defect correspond to the characteristics of the resonate sound wave. When the target object has a real defect, the signal receiver obtains target information where the resonant sound wave is received at the second port, wherein the target information comprises second data having characteristics of the resonant sound wave when the target object has the real defect. The method further comprises comparing the target information with the reference information to derive features of the real defect corresponding to the second data from the features of the imaginary defect corresponding to the first data.

In an embodiment, the accommodating space of the target object contains gas or fluid.

In an embodiment, the target object is a pipe, a trough or any other suitable structures, regardless of whether the accommodating space is close or open.

In an embodiment, the sound source device provides sounds of different frequencies.

In an embodiment, the sound source device provides sounds at different volumes.

In an embodiment, the resonant sound wave is in a standing wave state in the accommodating space.

In an embodiment, the characteristics of the resonant sound wave are a frequency shift or strength.

In an embodiment, the first data (their sources) are derived from sounds of a plurality of simulation frequencies provided by the sound source device, and the second data (their sources) are derived from sounds of a target bandwidth band provided by the sound source device. The target bandwidth band is within a range between any two of the plurality of simulation frequencies.

In an embodiment, the reference information is obtained by simulation of a computer program or obtained by a simulation of a mechanism arrangement.

In an embodiment, the second data of the target information is a difference of two frequencies detected by the signal receiver at two different time.

In an embodiment, the features of the imaginary defect are positions and/or sizes, and the positions and/or sizes of the features of the real defect are determined after the target information is compared with the reference information.

It is known from the above that in the detection system and the detection method according to the present disclosure, the sound source device introduces a sound into the target object actively. The frequency of the sound is in a range such that the sound can form a standing wave sound field in water, air or other fluid in the accommodating space to actuate a resonant sound wave. Therefore, a defect can be detected as the resonant frequency changes, and features of a real defect can be determined by comparing the target information with the reference information.

