JPH0833325B2 - Rotating machine abnormality monitoring device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating machine abnormality monitoring device for constantly monitoring abnormal vibration of a rotating machine using a vibration sensor.

[Conventional technology]

BACKGROUND ART Conventionally, in order to monitor an abnormality of a rotating machine, there has been provided a device provided with a vibration sensor, a temperature sensor, or an oil leak sensor, and detecting abnormal vibration of the rotating machine by a vibration frequency analyzing means. Further, there is also provided a device for detecting an abnormality of a rotating machine by using a vibration sensor as a pressure-proof and explosion-proof structure.

[Problems to be Solved by the Invention]

The above-described conventional rotating machine abnormality detection method and device can automatically detect abnormal vibration, abnormal temperature, oil leak, etc., but malfunctions occur due to vibration generated by load fluctuations during normal operation or fluid nozzles. There was a problem. Further, in the case of an imbalance abnormality or the like, it cannot be detected because the amplitude is large but the acceleration level is low.

Further, when detecting an abnormality of the rotating machine by the frequency analysis means, it is possible to continuously detect from low frequency vibration to high frequency vibration. However, in the digital signal transmission from the terminal control unit including the vibration sensor to the monitoring unit, ultra high speed transmission is possible. Required, a huge memory capacity is required, the device becomes very expensive,
When transmitting a plurality of sensor signals, the number of cables increases and the construction cost increases.

Furthermore, the vibration sensor generates a charge output in proportion to the acceleration, but in a rotating machine that transfers a flammable liquid, a high voltage is generated when an abnormally high impact is applied, and the leaked flammable gas (vapor) is generated. May ignite and explode.

In addition, the conventional technology in which the vibration sensor has a pressure-proof and explosion-proof structure is large and expensive, and the resonance point is low. There was a problem.

The present invention has been made to solve the above-mentioned conventional problems, and it is possible to reliably detect the type of abnormal vibration of a rotating machine, to provide a low cost, low construction cost, and explosion-proof rotating machine abnormality monitoring device. The purpose is to provide.

[Means for solving the problem]

A rotating machine abnormality monitoring device according to the present invention is configured by a terminal control unit and a monitoring unit including a vibration sensor attached to a detection target, and further, in the terminal control unit, an amplifier that amplifies an acceleration signal output of the vibration sensor, The output of this amplifier is branched into two, one output of which is passed through a high pass filter and then averaged, and the other output of which the output of the amplifier is branched into two is passed through a low pass filter and integrated. A processing circuit including a speed conversion unit for converting to a speed signal and an average value processing unit for processing an average value of the output of the speed conversion unit is provided, and further, a vibration sensor, a piezoelectric element, and an output of this piezoelectric element are amplified. The charge amplifier and the voltage limiting element for surge absorption connected in parallel with the piezoelectric element are sealed in a container with a filling resin to form an integrated structure.

The terminal control unit is connected to a monitoring unit by a two-wire line that transmits an information pulse and supplies a DC power source carrying this information. It is provided with a transmission control unit for digitally multiplexing and transmitting data.

[Action]

In the rotating machine abnormality monitoring device according to the present invention, the acceleration signal output of the vibration sensor is divided into an acceleration signal and a speed signal and transmitted, and the monitoring unit determines the bearing abnormality of the rotating machine from the acceleration, and unbalances from the speed. Anomalies such as misalignment are detected. And, in the terminal control unit,
DC power is supplied from the monitoring unit, and information pulses are transmitted on the DC voltage of this DC power.

〔Example〕

FIG. 1 is a block diagram showing the overall configuration of one embodiment of the present invention. In this figure, I is a terminal control unit, II is a monitoring unit, and a line III is connected between them.

The terminal control unit I includes a processing circuit 40 and a transmission control unit 50.
And an input / output port (I / O) 60, which is provided with a vibration sensor 10, a gas sensor 20, and an oil leak sensor 30 mounted on the rotating machine to be monitored.

The monitoring unit II includes a barrier 7 having a Zener diode or the like for preventing high voltage from being applied to the terminal control unit I.
0, receiving unit 71, alarm unit 72, D / A converter 73, output terminal 74 and the like.

To explain the outline of the operation, the vibration sensor of the terminal control unit I
The output of 10 is branched into an acceleration signal and a velocity signal in the processing circuit 40, processed as described later, and sent out from the input / output port 60 to the line III as a digital signal in the transmission control unit 50. The alarm unit 72 is operated when it is received by the receiving unit 71 and exceeds the specified value. If necessary, convert it to an analog signal with the D / A converter 73 and output terminal 7
Output from 4. Outputs of the gas sensor 20, the oil sensor 30, etc. are similarly transmitted to the monitoring unit II.

In the above case, the liquefied petroleum gas or the like that is gasified when leaked is detected by the gas sensor 20, and the fluid such as petroleum is detected by the gas leak sensor 30.

 Next, the vibration sensor 10 will be described.

FIG. 2 (a) shows an embodiment of the vibration sensor 10 of the present invention. 11 is a container, 12 is a piezoelectric element such as ceramic, 13 is a weight, 14 is a spring, 15 is a charge amplifier,
Reference numeral 16 is a filling resin, and 17 is a connector. This drive circuit is shown in FIG. 2 (b). In FIG. 2 (b), 18 is a voltage limiting element such as a Zener diode, and 19 is a constant current source.

This drive sensor 10 is an acceleration pickup, and a force proportional to an external force (acceleration) is applied to the piezoelectric element 12 by using a spring mass system using a weight 13 as shown in the figure, and electric charges are generated at both ends thereof. Piezoelectric element 12 charge output (PC
/ g) is conventionally a coaxial cable with a charge amplifier 15
Since it is connected to and converted to voltage output by the charge amplifier 15, readjustment is required because the line capacitance changes and the voltage pressure changes when the length of the coaxial cable changes. Since the amplifier 15 is built in the container 11 and driven by the constant current source 19 at a constant current, it is taken out as a voltage signal directly proportional to the acceleration, so that readjustment is not necessary.

FIG. 3 shows the processing circuit 40 and the transmission control section of the present invention.
It is a figure which shows the detail of 50.

In the processing circuit 40 of this figure, 41 is an amplifier, 42 is a high-pass filter, 43 is a detection unit, 44 is an average value processing unit,
Further, 45 is a low-pass filter, 46 is a speed conversion unit having an integration function, 47 is a detection unit, and 48 is an average value processing unit.

Further, in the transmission control unit 50, 51 is a sampling A / D conversion unit and 52 is a central value extraction processing unit, which takes in data three times and adopts the central value among them. Reference numeral 53 is a sampling A / D conversion unit, and 54 is a central value extraction processing unit, which takes data three times and takes a central value. 55 is a digital transmission unit.

 Next, the operation will be described.

The acceleration signal output from the vibration sensor 10 is amplified by the amplifier 41, and its output is branched into two. One acceleration signal passes through the high-pass filter 42, is detected by the detection unit 43, and is averaged by the average value processing circuit 44. By averaging in this way, the amount of transmission can be significantly reduced compared to the case where the output of the amplifier 41 is transmitted as it is.

The acceleration information converted into the DC level by the average value processing unit 44 is sent to the sampling A / D conversion unit 51 of the transmission control unit 50.
After being sampled by, the digital value is converted into a digital value, and the central value extraction processing unit 52 in the next stage takes the central value of the sampled values three times, removes the sudden value, and transmits it from the digital transmission unit 55 to the monitoring unit II. To do.

An example of the transmission waveform in this case is shown in FIG. That is, the DC power is supplied from the monitoring unit II through the line III in a two-wire system (for example, 4 mA). The digital signal rides on this and is transmitted as an information pulse of 7mA ± 3mA. Therefore, it is possible to supply the direct current and transmit the information pulse by the two-wire system.

Now, in the case where a bearing abnormality occurs in the rotating machine that is the object to be detected in the above, the output of the vibration sensor 10 becomes an acceleration signal with many high frequency components, so the average value processing unit 44
Output becomes large and a bearing abnormality is reported.

On the other hand, in this case, the output of the amplifier 41 is the low-pass filter 45.
However, since the low-pass filter 45 cannot be currency, the output of the average value processing unit 48 is small and an alarm cannot be issued.

On the other hand, when an abnormality occurs in the rotating machine due to imbalance, misalignment, or the like, the vibration sensor 10 outputs a low-frequency acceleration signal, which is amplified by the amplifier 41. The output of the amplifier 41 can now pass the low pass filter 45 and not the high pass filter 42. The acceleration signal that has passed through the low-pass filter 45 is integrated into a speed signal by the speed conversion unit 46, then detected by the detection unit 47, and averaged by the average value processing unit 48. The averaged speed signal is digitized by the sampling A / D conversion unit 53, the center value is extracted by the center value extraction processing unit 54, and the digital transmission unit 55.
Sent from.

Although not shown, the outputs of the gas sensor 20 and the oil leak sensor 30 are simply amplified by the processing circuit 40 and are transmitted to the transmission control unit 50.
Is input to the digital camera, and is digitized and transmitted in the same manner as the acceleration signal or the speed signal described above.

Various well-known gas sensors 20 and oil leak sensors 30 can be used.

〔The invention's effect〕

As described above in detail, the rotating machine abnormality monitoring device according to the present invention includes a terminal control unit and a monitoring unit each including a vibration sensor attached to a detected object, and the terminal control unit further includes an acceleration of the vibration sensor. An amplifier that amplifies the signal output, an output of this amplifier is branched into two, an average value processing unit that processes one of the outputs after passing a high-pass filter, and a sudden value of the data after AD conversion is removed. A central value extraction processing unit, a speed conversion unit that converts the output of the amplifier into two, which is obtained by branching the output of the amplifier through a low-pass filter, and then integrates it into a speed signal. A processing circuit including a value processing unit and a central value extraction processing unit that removes a sudden value of data after AD conversion is provided.
Furthermore, the vibration sensor is integrated with a piezoelectric element, a charge amplifier that amplifies the output of this piezoelectric element, and a voltage limiting element for surge absorption that is connected in parallel with the piezoelectric element, sealed in a container with a filling resin. Since it is formed as, since the output of the vibration sensor is processed separately in the acceleration signal and the velocity signal,
It is possible to detect a bearing abnormality of the rotating machine from the acceleration signal, and it is possible to detect a long-period vibration due to the unbalance or misalignment of the rotating machine from the speed signal.

In addition, the two branched outputs of the amplifier are subjected to AD conversion in the central value extraction processing unit, and the sudden data is removed, so that the reliability of the data is improved.

Since the charge output generated from the piezoelectric element is converted into a voltage output by the charge amplifier, constant current driving enables transmission that is not affected by the line length, and the vibration sensor is a filled resin. Since it is sealed, it protects each part in the container and can be used for a long time even when installed in a vibrating place.

In addition, the monitoring unit and terminal control time is the supply of direct current,
Since the transmission of the information pulse is performed by the 2-wire type line,
It has the advantage that it can be configured with the minimum number of lines.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall construction of an embodiment of the present invention, and FIGS. 2 (a) and 2 (b) are sectional views showing the construction of the vibration sensor in the embodiment of FIG. 1 and its drive. Circuit diagram, FIG. 3 is a block diagram showing the details of the processing circuit and the transmission control section of the embodiment of FIG. 1, and FIG. 4 is a waveform diagram for explaining the relationship between the power supply and the information pulse of the present invention. . In the figure, I is a terminal control unit, II is a monitoring unit, 10 is a vibration sensor,
18 is a voltage limiting element, 20 is a gas sensor, 30 is an oil leak sensor,
40 is a processing circuit, 41 is an amplifier, 42 is a high-pass filter, 43
Is a detection unit, 44 is an average value processing unit, 45 is a low-pass filter,
46 is a speed conversion unit having an integration function, 47 is a detection unit, 48 is an average value processing unit, 49 is a transmission control unit, 51 and 53 are sampling A / D conversion units, 52 and 54 are central value extraction processing units, and 55. Is a digital transmitter.

Claims (2)

[Claims] 1. A terminal control unit having a vibration sensor attached to an object to be detected and a monitoring unit, wherein the terminal control unit further includes an amplifier for amplifying an acceleration signal output of the vibration sensor, and an output of the amplifier. Is divided into two, and one of the outputs is subjected to a high-pass filter to perform an average value processing, an average value processing section for removing a sudden value of the data after AD conversion, and an output of the amplifier. The other output that has been branched into two is passed through a low-pass filter, then integrated and converted into a speed signal, an average value processing unit that performs an average value processing on the output of this speed conversion unit, and a data after AD conversion. A processing circuit including a central value extraction processing unit that removes a sudden value is provided, and the vibration sensor is connected in parallel with the piezoelectric element, a charge amplifier that amplifies the output of the piezoelectric element, and the piezoelectric element. It An abnormality monitoring device for a rotating machine, characterized in that a voltage limiting element for absorbing surge is sealed in a container with a filling resin to be formed as an integrated structure. 2. A terminal control unit is connected to a monitoring unit by a two-wire line for transmitting an information pulse and supplying a DC power supply carrying this information, and further, outputs of a processing circuit are connected to each other. The rotating machine abnormality monitoring device according to claim 1, further comprising a transmission control unit that performs channel / digital multiplexing and electric transmission.