JPS6412334B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hole inspection device capable of quickly inspecting a manifold for clogging.

Conventionally, to inspect the through holes of branch pipes, manifolds, etc., 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 not only requires time and effort to insert the inspection rod into each hole, but also tends to cause detection errors due to burrs, etc., and the latter method is affected by the connection state with the pressure source, so There was a problem that the sensitivity to clogging in areas far from the hole was low, resulting in detection errors.

In view of these problems, the present invention provides an easy-to-use and highly sensitive hole inspection device that connects a flute 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 reference numeral 1 in the figure is a master whistle that generates acoustic vibrations according to the hole state of the manifold pipe T to be inspected. 2. At one end extending outward, there is a manifold pipe T to be inspected.
A connecting portion 3 is provided to airtightly hold the main body of the air conditioner, and an air hose extending from an air pressure source 4 is connected to the other end located within the sound insulation chamber 2. A microphone 5 that converts acoustic vibrations from the master whistle 1 into electrical signals is disposed within the sound insulation chamber 2, and the signals from this are output to a signal processing section 6. The signal processing unit 6 determines the quality of the manifold to be tested 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, and a type of the manifold to be tested. A filter group 8 that sets the analysis frequency band according to , and 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 a master standard manifold pipe is fitted into the connection part 3 and air is blown from the other end, the master whistle 1 produces a tone that is determined by the position and length of the manifold hole. Generates acoustic vibrations. This acoustic vibration is captured by the microphone 5, its center frequency is detected by the spectrum analyzer 9, and stored in the determination circuit 10 as a reference frequency. After completing these preparations, 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 state of the hole in the manifold pipe to be tested. Since this occurs, it is easy to determine whether the product is good or bad based on the deviation from the reference frequency.

〔Example〕

When 2Kg/cm ² of air is flowing, the center frequency is 1500
When a standard 8-way branch pipe shown in Figure 2A is connected to the tip of a master flute that generates Hz acoustic vibrations, a spectogram as shown in Figure 2B is obtained, and its center The frequency was 1304Hz. When we connected this to a branch pipe (C in the same figure) with one of the holes closed, the center frequency was 1273.
Hz (D in the same figure), and it was possible to detect a blockage in the branch pipe from the deviation between the two. Furthermore, when we conducted an experiment by blocking the through hole that had the least effect on changes in the center frequency, we found that a shift of 7 Hz occurred downward, and that clogging could be detected even in this case.

As explained above, according to the present invention, the manifold pipe to be inspected is connected to the master whistle, and the manifold pipe is blown, and clogging of the manifold pipe is detected from any of the center frequencies at that time. Despite this, abnormalities in the through holes can be detected easily and in a short time, and line inspections of manifold pipes, etc. can be realized.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a device showing an embodiment of the present invention, and FIG. 2 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, 3...Connection part, 4...Pneumatic pressure source, 6...
...Signal processing section.

Claims (1)

[Claims] 1. A blowing means having a connecting part of the manifold to be inspected at its tip, an acoustic-to-electric conversion means for converting the acoustic vibrations generated by the means into an electrical signal, and a center frequency of the standard manifold and a signal from the conversion means. and means for detecting a deviation from the center frequency of the manifold.