JPS5985953A - Through hole inspecting device for manifold - Google Patents

Abstract

PURPOSE:To detect the abnormality in a through hole simply in a sort time and to make it possible to realize the line inspection and the like of a manifold by a simple device, by connecting the manifold to be inspected to a master whistle, blowing the whistle, and detecting the clogging of the manifold based on the deviation of the central frequency at this time. CONSTITUTION:In a sound shielding chamber 2, a microphone 5, which transduces the acoustic vibration from a master whistle 1 into an electric signal, is arranged. The signal from the microphone is outputted to a signal processing part 6. A standard manifold, which is to become a master, is inserted into a connecting part 3, and air is blown in from the other end. Then, the master whistle 1 generates acoustic vibration having a tone, which is determined by the position, length, and the like of a through hole of the manifold. The acoustic vibration is captured by the microphone 5. Its cenral frequency is detected by a spectrum analyzer 9, and stored in a judging circuit 10 as a standard frequency. After this preparation, a manifold to be inspected T is set in the master whistle 1, and air is blown in. Then, deviation is yielded in the frequency, which is inputted to the signal processing part 6 in correspondence with the state of the through hole of the manifold to be inspected. Thus the quality is readily judged by the deviation from the standard frequency.

Description

[Detailed description of the invention] This invention relates to a through-hole inspection device that can perform

Conventionally, to inspect the through holes of branch pipes and manifolds, there are two methods: inserting an inspection rod into each hole and detecting the presence or absence of clogging from the insertion depth, or applying positive or negative pressure to the main hole side. A method was used to detect the presence or absence of a blockage based on the fluid flow generated at this time. However, the former method requires a lot of time and effort to insert the test rod into the through hole, and is prone to detection errors such as paris, while the latter method is difficult to insert the test rod into the hole. There was a problem in that the sensitivity to clogging in the part remote from the main hole, which receives the color tube, was low and detection errors occurred.

The present invention solves these problems by providing an easy-to-use and highly sensitive hole inspection device that connects a whistle to the manifold to be inspected and detects the presence or absence of clogging from the parameters of the acoustic vibrations generated. The purpose is to provide.

Therefore, details of the present invention will be explained below based on illustrated embodiments.

FIG. 1 is a block diagram of an apparatus showing an embodiment of the present invention, and the reference numeral 1 in the figure is a master whistle that generates acoustic vibrations according to the hole condition of the manifold to be inspected. One end extending outside the chamber 2 is provided with a connecting portion 6 for airtightly holding the main trunk of the manifold pipe T to be inspected, and an air hose extending from the air pressure source 4 is provided at the other end located within the sound insulation chamber 2. is connected. A microphone 5 for converting acoustic vibrations from the master flute 1 into electrical signals is disposed within the sound insulation chamber 2, and signals from this microphone are output to a signal processing section 6.

The signal processing unit 6 determines the quality of the manifold to be inspected based on the acoustic vibrations detected by the microphone 5, and includes an amplifier 7 that amplifies the output from the microphone 5 to a predetermined level.
, a filter group 8 that sets the analysis frequency band according to the noodles of the manifold to be inspected, a spectrum analyzer 9 that detects the center frequency of the output from this, and a master whistle 1 by connecting the standard manifold. memorize the center frequency when you play the
It is comprised of a determination circuit 10 that compares this frequency with the center frequency of the manifold to be tested, indicates the deviation thereof, and at the same time determines whether the manifold to be tested is good or bad.

In this embodiment, when the master standard manifold pipe is fitted into the connection part B and air is blown from the other end, the master whistle 1 produces an acoustic vibration with a tone determined by the position and length of the manifold hole. occurs. This sound vibration is captured by the microphone 5, its center frequency is detected by the spectrum analyzer 9, and is stored in the determination circuit 10 as a reference frequency. After completing the preparations in this way, when the manifold pipe T to be tested is set in the master whistle 1 and air is blown into it, the frequency input to the signal processing section 6 will be biased depending on the condition of the hole in the manifold pipe to be tested. Therefore, the quality can be easily determined by observing the deviation from the reference frequency.

〔Example〕

When 2 kg/i of air flows, the center frequency is 1500
When we used a master whistle that generates Hz acoustic vibrations and connected the standard 8-way branch pipe shown in Figure 2A to the tip of the whistle, we obtained the spectogram shown in Figure 2B.
Its center frequency was 1304Hz.

When we connected this to a branch pipe with one of the holes closed (C in the same figure), we found that the center frequency was 1273Hz (D in the same figure).
Therefore, we were able to detect a blockage in the branch pipe from the deviation between the two. Furthermore, an experiment was conducted by blocking the through hole that has the least influence on changes in the center frequency, and it was found that a shift of 7 Hz occurred on the lower side of the axis, and that clogging could be detected even at tl.

As described above, according to the present invention, the manifold pipe to be inspected is connected to the master whistle and blown, and clogging of the manifold pipe is detected from the shift in the center frequency at that time.
Although it is a simple device, it can detect abnormalities in the through hole easily and in a short time, and can perform line inspections of manifold pipes.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an apparatus showing one embodiment of the present invention, and FIG.
The figure is an explanatory diagram showing the detection accuracy of the device according to the present invention. T...Test manifold 1...Master whistle 2...
・Sound insulation room 6...Connection part 4...Pneumatic pressure source 6...Signal processing unit Applicant Honda Motor Co., Ltd. agent Patent attorney Keiji Nishiyo Katsuhiko Kimura 1st cause

Claims (1)

[Claims] A blowing means with a connecting part of the manifold to be inspected at its tip, and an acoustic device that converts the acoustic vibrations generated by the means into an electrical signal.
A manifold through-hole inspection device comprising electrical conversion means and means for detecting a deviation between the center frequency of a standard manifold and the center frequency of a signal from the conversion means.