JPH08247077A - Fluid compression diagnosing device for compressor - Google Patents

Abstract

PURPOSE: To judge a fluid compression component and a metallic contact component by providing a judgement part to carry out frequency separation in addition to a conventional hydraulic compression diagnostic device concerning a diagnostic device to judge the hydraulic compression component and the metallic contact component from an oscillation signal peak waveform caused by hydraulic compression of a compressor. CONSTITUTION: Oscillation of a compressor 1 is detected by a sensor 2 constituted of a piezoelectric element, amplified by an amplifier 3, taken off of a waveform by a trigger device 4, separated in frequency by a frequency separation device 5, detected in envelope by an envelope detection device 6, converted in A/D by an A/D converter 7, judged in hydraulic compression component and metallic contact component by a judgement part, output by an output device 9 and recorded by a recorder 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diagnostic device for determining a liquid compression component and a metal contact component from a vibration signal peak waveform resulting from liquid compression of a compressor.

[0002]

2. Description of the Related Art A typical compressor is one used in a refrigerating machine. The above compressor compresses a refrigerant gas in a cylinder and discharges it to a cooling system. However, depending on the state of the cooling system, the refrigerant may be sucked into the cylinder not as gas but as liquid, and at that time, a liquid compression phenomenon occurs in the cylinder, which causes abnormal stress on the compressor and causes abnormal compression. There were cases.

Therefore, in the development study of the compressor and the system, the voltage signal obtained from the vibration of the compressor was envelope-detected, and the liquid compression phenomenon was judged by the peak of the signal.

An example of the above-described conventional liquid compression diagnostic device will be described below with reference to the drawings.

FIG. 4 shows an example of a device for detecting a liquid compression phenomenon of a conventional compressor. Reference numeral 19 is a closed case of the compressor 1, 20 is a roller, and 21 is a vane, which always keeps contact with the roller 20 to form a boundary between the compression chamber and the suction chamber. Reference numeral 22 is a crankshaft, which is the shaft of the roller 20.

Reference numeral 23 is a suction port, and 24 is a cylinder through which the refrigerant is sucked from the suction port 23. Reference numeral 2 is a sensor composed of a piezoelectric element, which is installed on the exterior of the compressor for measurement. Sensor 2 composed of a piezoelectric element via envelope detection device 6
The output device 9 outputs the signal from the.

The operation of the conventional liquid compression diagnostic device for a compressor configured as described above will be described below.

When the crankshaft 22 is rotated by the electric motor, the refrigerant flows from the suction port 23 into the cylinder 2.
When the roller 20 is sucked into the roller 4, the volume of the roller 20 is reduced by the swirling operation of the roller 20 and compressed, and the refrigerant compressed from the discharge cut valve is discharged into the compressor through the muffler.

Therefore, when the liquid refrigerant enters from the suction port 23, the pressure is considerably increased at the end of the compression and is discharged as a high pressure liquid, which causes a liquid compression phenomenon.

At this time, the vibration peak caused by the liquid compression is detected by the sensor 2 composed of a piezoelectric element, and the vibration waveform is output from the output device 9 via the envelope detection device 6.

If the peak waveform of the vibration signal exceeds the threshold line 27 corresponding to the maximum pressure at the time of gas compression, it is judged that the liquid is compressed.

FIG. 5 shows an output example thereof. Reference numeral 25 is a vibration signal waveform during liquid compression. Reference numeral 26 is a vibration signal peak waveform that represents liquid compression that appears every rotation, and the pressure is rapidly increased by liquid compression, which causes strong shock vibration and propagates through the internal parts of the compressor to appear as shock vibration in the appearance of the compressor. You can see that

Numeral 27 is a threshold line corresponding to the maximum pressure line during normal compression. The liquid compression was determined as liquid compression when the peak value of the vibration signal peak waveform 26 representing this liquid compression exceeds the threshold line 27.

[0014]

However, in the above-described conventional determination method, it was difficult to determine the liquid compression component and the metal contact component contained in the vibration signal peak waveform.

In view of the above problems, the present invention aims to clarify the judgment of the liquid compression component and the metal contact component by performing frequency separation and providing a judgment unit in addition to the conventional liquid compression diagnostic device. There is.

[0016]

In order to achieve the above object, a liquid compression diagnostic device for a compressor of the present invention comprises a piezoelectric element which detects a liquid compression signal from an operating compressor and outputs a voltage signal. A sensor, an amplifier that amplifies the signal, a trigger device that uses a vibration signal peak resulting from liquid compression as a trigger signal from the amplified signal, and a frequency separation device that frequency-separates the vibration signal peak, Envelope detection device for envelope-detecting the frequency-separated signal, A / D converter for A / D converting the detected signal, determination unit for determining liquid compression component and metal contact component, and the determination result Is provided, and a recording device for recording the determination result.

Further, the vibration signal peak waveform is detected from the vibration signal waveform, and the liquid compression component and the metal contact component are determined based on the magnitude relationship of the respective waveform peak values obtained by frequency-separating the detected vibration signal peak waveform. It is characterized by quantitative and accurate clarification.

[0018]

According to the present invention, with the above configuration, it is clear that the liquid compression component and the metal contact component contained in the peak waveform of the vibration signal output from the sensor composed of the piezoelectric element installed on the appearance of the compressor are clear. Became.

Further, by performing frequency separation and clarifying the judgment of the liquid compression component and the metal contact component, it is possible to confirm the peak waveform of the vibration signal caused only by the liquid compression phenomenon.

[0020]

【Example】

(Embodiment 1) A first embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 2 is a sensor composed of a piezoelectric element attached to the compressor 1, and detects a signal due to liquid compression of the compressor 1. An amplifier 3 amplifies the detected signal. Reference numeral 4 denotes a trigger device that uses a vibration signal peak resulting from liquid compression as a trigger signal from the amplified signal.

Reference numeral 5 is a frequency separation device for frequency-separating the vibration signal peak. Reference numeral 6 is an envelope detector for detecting the frequency-separated signal. Reference numeral 7 is an A / D converter for A / D converting the detected signal. Reference numeral 8 is a determination unit that determines a liquid compression component and a metal contact component from the A / D converted signal. An output device 9 displays the determination result. A recording device 10 records the determination result.

The operation of the embodiment constructed as above will be described. The liquid compression signal of the compressor 1 is detected by the sensor 2, and the detected signal is amplified by the amplifier 3. From the amplified signal, the vibration signal peak resulting from the liquid compression is triggered by the trigger device 4 to extract the vibration signal peak waveform. The vibration signal peak waveform is LowPass with the frequency of the frequency separation device 5 as a boundary.
Filter (hereinafter LPF) signal and HighPass
It is frequency-separated into a filter (hereinafter referred to as HPF) signal.

The frequency-separated signals and the original waveform signal cut out by the trigger device 4 are envelope-detected by the envelope detector 6. Each detected signal is converted from an analog signal to a digital signal by the A / D converter 7. The determination unit 8 determines whether the A / D converted signal is a liquid compression component or a metal contact component.

By displaying the determination result on the output device 9, it is possible to compare the LPF waveform, the HPF waveform, and the original waveform. Further, by recording the determination result with the recording device 10, post-processing after measurement and other analysis can be performed.

Liquid compression and metal contact can be determined from the above-mentioned configuration. (Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

In contrast to the first embodiment, a vibration signal peak waveform judging means for judging the liquid compression component and the metal contact component after frequency separation is defined.

The boundary frequency for frequency separation is that the component of only liquid compression occurs around 5 kHz, and the natural frequencies of the rollers 20 and the vanes 21, which are the parts of the compressor related to liquid compression, are 10 kHz or more. It was set to 10 kHz.

As shown in FIG. 3, the vibration signal waveform is input to the input section 15. The peak detection unit 16 detects the vibration signal peak waveform from the input vibration signal waveform. 10
The peak value determination unit 17 determines the magnitude relationship between the waveform peak value of the kHz LPF and the waveform peak value of the 10 kHz HPF. Waveform peak value of 10 kHz LPF ≧ 10 kHz HP
If it is a waveform peak value of F, the peak is determined to be a liquid compression component, and a waveform peak value of 10 kHz LPF <10 kHzH
If it is the peak value of the waveform of PF, the peak is determined to be a metal contact component and is output by the output unit 18.

FIG. 2 shows the peak detector 16 in this case, for example.
4 original waveforms of ,, detected at, 10kHz
The output results of the LPF waveform and the 10 kHz HPF waveform are shown. , Is a liquid compression component because the waveform peak value of 10 kHz LPF ≥ 10 kHz HPF waveform peak value, and is a metal contact component because the waveform peak value of 10 kHz LPF <10 kHz HPF waveform peak value I understand.
From the above, with this determination means, 10 kHz LPF, 1
The liquid compression component and the metal contact component are quantitatively determined from the waveform peak value of 0 kHz HPF.

[0031]

As described above, according to the present invention, a sensor composed of a piezoelectric element for detecting a liquid compression signal from a compressor in operation and outputting a voltage signal, an amplifier for amplifying the signal, and an amplifier for amplifying the signal. A trigger device that uses a vibration signal peak due to liquid compression as a trigger signal from among the signals, a frequency separation device that frequency-separates the vibration signal peak, and an envelope detection device that envelope-detects the frequency-separated signal. An A / D converter for A / D converting the detected signal, a determination unit for determining a liquid compression component and a metal contact component, an output device for outputting the determination result, and a recording device for recording the determination result. By including the above, it is possible to determine the liquid compression component and the metal contact component included in the vibration signal peak waveform.

Further, a peak detecting means for detecting a vibration signal peak waveform from the vibration signal waveforms inputted in the judgment of the liquid compression component and the metal contact component, and a 10 kHz LPF.
It is possible to quantitatively and accurately determine the liquid compression component and the metal contact component by using the peak value determination means for determining the magnitude relationship between the waveform peak value of 1 and the waveform peak value of 10 kHz HPF.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a liquid compression diagnostic device for a compressor showing a first embodiment of the present invention.

FIG. 2 is an original waveform to be determined by the present invention and 10 kHzL
Comparison diagram of vibration waveform of PF and 10kHz HPF

FIG. 3 is a waveform processing flowchart showing a second embodiment of the present invention.

FIG. 4 is a block diagram of an apparatus for detecting a liquid compression phenomenon of a compressor showing a conventional example.

FIG. 5 is a vibration waveform diagram detected by a sensor including a piezoelectric element showing the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Sensor comprised of a piezoelectric element 3 Amplifier 4 Trigger device 5 Frequency separation device 6 Envelope detection device 7 A / D converter 8 Judgment part 9 Output device 10 Recording device

Claims (2)

[Claims] 1. A sensor composed of a piezoelectric element for detecting a liquid compression signal from a compressor in operation and outputting a voltage signal,
An amplifier that amplifies the signal, a trigger device that uses a vibration signal peak resulting from liquid compression as a trigger signal from the amplified signal, a frequency separation device that frequency-separates the vibration signal peak, and the frequency-separated signal. Envelope detection device for detecting the envelope, an A / D converter for A / D converting the detection signal, a determination unit for determining the liquid compression component and the metal contact component, and an output device for outputting the determination result When,
A liquid compression diagnostic device for a compressor, comprising: a recording device for recording the determination result. 2. A peak detection means for detecting a vibration signal peak waveform from the vibration signal waveforms inputted in the judgment of the liquid compression component and the metal contact component, and the magnitude relationship between the frequency-separated waveform peak values is judged. 2. The liquid compression diagnostic device for a compressor according to claim 1, further comprising: