JPH0222665Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a device for detecting leakage of gas or liquid.

When gas or liquid leaks through micropores,
It is well known that they generate a wide range of sound that spans the ultrasonic band of tens of kilohertz.

Therefore, it has been put into practical use to use an ultrasonic microphone to detect leaked sound contained in the ultrasonic band, convert it to an audible frequency, and listen to the sound.

In this case, the magnitude of the leakage can be heard as the magnitude of the sound intensity. However, the human ear has a very weak ability to distinguish differences in intensity, so it is difficult to discern the degree of leakage unless there is a large difference.

This invention focuses on the fact that the human ear is extremely sensitive to differences in frequency, converts the intensity of sound into frequency, and distinguishes the intensity of received sound based on the high and low frequencies. It is.

Next, an example will be explained. In Figure 1, 1 is a sensor using an ultrasonic microphone, etc.
2 is an amplifier, 3 is a mixer, 4 is a local oscillator, 5 is a detector, 6 is a voltage/frequency converter (V-F converter), and 7 is an output terminal.

The leaked sound is picked up by the sensor 1, amplified by the amplifier 2, and then applied to the mixer 3.The output, which is mixed with the output of the local oscillator 4 and frequency-converted, is detected by the detector 5, and then Via the V-F converter 6, it is converted to a frequency proportional to the input level as shown in Figure 2.In the case of a weak input, the frequency is converted to a low frequency as shown in Figure 3A, and in the case of a strong input, it is converted to a frequency proportional to the input level.
As shown in FIG. 2B, the output is controlled to a constant level at a high frequency and is sent to the output terminal 8.

Therefore, when the signal appearing at the output terminal 7 is listened to using a speaker or a headphone, the magnitude of the leakage can be distinguished as a frequency difference controlled to a constant level, making it very easy to distinguish. There is.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an embodiment of the present invention. FIG. 2 is an explanatory diagram of a V-F converter that converts the frequency into a signal proportional to the intensity of the signal. Figure 3 shows an example of output for strong and weak inputs. 1...Sensor, 2...Amplifier, 3...Mixer, 4...Local oscillator, 5...Detector, 6...V
-F converter, 7...output terminal.

Claims (1)

[Scope of utility model registration request] A sensor that picks up the sound generated when gas or liquid leaks, a means for converting the frequency of the sound picked up by the sensor into an audible frequency, a detection means for detecting the output obtained by the means, and the detection means. and a V-F converter that converts the output detected by the means into a frequency proportional to the output level, and the V-F converter outputs a low frequency when the input is weak, and a high frequency when the input is strong. A gas or liquid leak detection device characterized by being able to obtain an output at a constant level.