JPS6264918A - Apparatus for monitoring vibration - Google Patents

Abstract

PURPOSE:To enable the efficient operation of a plant by more accurately grasping the state of a machine, by detecting vibration increasing and decreasing cyclically by mounting a peak hold circuit and a reset circuit. CONSTITUTION:The electric signal obtained by a vibration signal detecting circuit 1 is inputted to a level discriminating circuit 3 to which a plurality of reference levels have been preset through an amplifying circuit 2 to discriminate which reference levels vibration belongs to. Next, the discrimination result is inputted to a flashing circuit 5 and a peak hold circuit 6. Subsequently, the output from the circuit 5 is intermittently inputted to a logical circuit 7 while the circuit 6 allows the max. level to succeedingly input to the logical circuit 7 only when the inputted reference level is the max. one. In order to observe whether this vibration frequently appears, the peak hold circuit 6 is preset to the state before operation using a reset circuit 8. By this method, the signal of the max. level appearing with a short time and the vibration of a lower rank level always appearing can be displayed in parallel.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] This invention detects the vibration of a mechanical structure in operation, such as an electric motor, as an electrical signal, and detects the level of vibration obtained through the detected quantity of electricity. The present invention relates to a device for detecting abnormalities in structures.

[Prior art and its problems]

Vibration that occurs during the operation of mechanical structures such as electric motors accurately represents the condition of moving parts, and it responds sensitively to both gradual aging and sudden abnormalities, so it is important for the operation of machinery. considered essential for surveillance.

Generally, this mechanical vibration is measured by electrically detecting the speed and acceleration of the vibration, and inputting the detected amount of electricity into a vibration meter that indicates the magnitude of the vibration. In large-scale plants in industrial fields such as electric power, steel, and chemicals that use many rotating machines, the condition of machines through vibration is actively monitored in order to improve plant availability and effectively carry out maintenance and repairs. Normally, lifeguards patrol regularly and measure vibrations. However, with vibration measurements carried out periodically like this, it is only possible to grasp the vibration at that point in time, and on the other hand, the vibration level of the machine does not necessarily stay within a constant range. Not limited to
In some cases, the amount increases and decreases intermittently or periodically, making it impossible to accurately grasp the state of the machine.

[Purpose of the invention]

In order to solve the above-mentioned problems, the present invention not only grasps machine vibrations only at the time of measurement, but also grasps vibrations that increase and decrease intermittently or periodically during operation to better understand the state of the machine. It is an object of the present invention to provide a vibration monitoring device that can accurately grasp the vibrations of a structure and contribute to more efficient operation of the brand. a circuit for amplifying the detected ventilation signal; a level discrimination circuit for classifying the level of vibration detected and amplified through the electric signal according to a plurality of reference levels set in advance in stages; a display circuit to which a signal of a reference level to which the divided vibration levels belong is input, and a display circuit that holds the signal of the highest level or the peak value of the vibration level when a vibration belonging to the highest level among the plurality of reference levels appears; The peak hold circuit that continuously outputs the peak hold circuit and the reset circuit that returns the peak hold circuit to the state before operation are biased and appear for a short time! &
The above object is achieved by displaying high-level vibrations and lower-level vibrations that always appear in parallel.

[Embodiments of the invention]

FIG. 1 shows the first circuit configuration of the vibration monitoring device based on the present invention.
An example is shown below. The vibration of a mechanical structure is converted into an electrical signal using a vibration detection circuit 1 attached to the mechanical structure. For example, a piezoelectric transducer that measures the acceleration of vibration or an electrodynamic type that measures the speed is used for conversion. Use a vibrating element. The electrical signal proportional to the vibration level obtained in this way is amplified in the amplifier circuit 2 and input to the level discrimination circuit 3 at the next stage. A plurality of reference levels are set in advance in a stepwise manner in the level discrimination circuit 3, and by comparing the vibration level input to this level discrimination circuit with the reference level of this camera, the input vibration level is determined. Determine which reference level it belongs to. This standard level is set to three levels, for example, with the highest level being the upper limit of the level range where the machine condition is considered normal, the upper limit of the level range where caution is required, and the appropriate level within the level range where the machine is considered dangerous. set, the machine status is these normal,
Attention, determine which level belongs to the highest. This determination result is input to the blinking circuit 5 and the peak hold circuit 6 in parallel. In the blinking circuit 5, a blinking circuit corresponding to the input reference level is activated, and the output from this circuit is inputted to the logic circuit 7 intermittently. On the other hand, the peak hold circuit continues to input the highest level signal to the logic circuit 7 only when the input reference level is at the highest level.

This logic circuit 7 is composed of the same number of sets of OR circuits as the number of stages of the reference level to be determined, for example, 7a corresponds to the highest level, 7b corresponds to the caution level, and 7c corresponds to the normal level. As an OR circuit,
If the reference level discriminated by the level discrimination circuit 3 is a caution level, the output register 4b connected to the output side of 7b
t turns on and off, causing the lamp 4bl to blink. Furthermore, when a vibration level belonging to the highest level appears during operation of the machine, this highest level signal is input to the OR circuit 7a from both the blinking circuit 5 and the peak hold circuit 6, and the display lamp 4aJ of the display circuit 4 is inputted to the OR circuit 7a. Turn it on. Here, the output from the peak hold circuit 6 is continuously output from the OR circuit 7a.
However, the output from the blinking circuit 5 is not continuous because the highest level of vibration usually appears only intermittently or periodically. Therefore, in order to continue the output of the OR circuit 7a and continuously light the indicator lamp 4aJ, for example, although not shown in the figure, a memory circuit is added to the OR circuit 7a to continue the output, and a predetermined highest level is set. When the occurrence of the highest level of vibration is confirmed in this way, the peak hold circuit is activated using the reset circuit 8 to see if this vibration appears frequently. If the highest level indicator lamp is lit again during the next monitoring, this indicates that vibrations at the highest level occur frequently. If not, it can be seen that the highest level of vibration is less frequent. It is also possible to change the highest level set value to another level when resetting. In the above explanation, in order to easily distinguish between the highest level and the lower level, the highest level vibration is By lighting the indicator lamp, lower level vibrations that always appear were indicated by blinking the indicator lamp, but the display method could be reversed, or the indicator lamp could be a color-coded light emitter, and the display would be lit. It is possible to make a free choice depending on the monitoring concept, such as standardizing the display on either flashing or blinking.

FIG. 2 shows a second circuit configuration of the vibration monitoring device based on the present invention.
Unlike FIG. 1 which shows an example of this, a vibration waveform whose level has not been discriminated is input to the peak hold circuit 6, so the maximum peak value of this input vibration waveform is held and transferred to the next stage. When this maximum peak value is determined to belong to the highest level, the highest level signal is output and the indicator lamp 4al is lit in the same way as in the case of Fig. 1. . If the level discriminator circuit 3bJ were configured to have multiple types of discriminator level values in the highest level region instead of using only one type, it would be possible to reset the peak hold circuit after confirming that the indicator lamp 4al is on. At this time, the highest level discrimination value to be monitored next can be easily switched, which is convenient for the operation of the vibration monitoring device.

FIG. 3 shows a third embodiment of the circuit configuration of a vibration monitoring device based on the present invention. This embodiment differs from the embodiment shown in FIG. A display circuit is constituted by a series of indicator lamps 4b for vibrations in the area and a series 4a of indicator lamps for vibrations in a lower level area, and a blinking circuit is omitted.

If the discrimination level value of the level discrimination circuit 3b is set to multiple types (three types in this case), the vibration level in the highest level area is displayed in each stage by the display lamps 4b+14b.
t t 4t)s can be displayed widely,
Convenient for discovering abnormal vibrations. In addition, since the display lamp series 4a has a different position from the series 4b, it can be easily distinguished from series 4b without blinking as shown in Figures 1 and 2, simplifying the circuit configuration. can do.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a vibration monitoring device includes a circuit that detects vibrations of a structure as an electrical signal, a circuit that amplifies the detected electrical signal, and a circuit that amplifies the detected electrical signal. a level discrimination circuit that classifies the level of the detected and amplified vibration according to a plurality of reference levels set in advance in stages; a display circuit to which a reference level signal to which the classified vibration level belongs is input; When a vibration belonging to the highest level among the reference levels appears, a peak hold circuit holds and continuously outputs the signal of the highest level or the peak value of the vibration level, and the peak hold circuit is returned to the state before operation. Equipped with a reset circuit, the highest level vibration that appears for a short time and the lower level vibration that always appears are displayed in parallel with -, so that it is possible to detect abnormal vibrations that increase or decrease intermittently or periodically during operation. By using a reset circuit to return the peak hold circuit to its pre-operation state, it is possible to determine the frequency of abnormal vibrations and the magnitude of abnormal vibrations by changing the maximum level setting. Compared to conventional monitoring methods that only grasp vibration at the time of measurement, it is possible to understand the condition of machinery much more accurately, making it possible to operate plants more efficiently.

In addition, if the vibration level is displayed not only by lighting and flashing lamps but also by using colored light emitters, it will be easier to distinguish the vibration level, and the monitoring work will not require much labor and time. This is convenient for vibration monitoring when there are many machines and many parts to be measured.

[Brief explanation of drawings]

1 to 3 are diagrams each showing an embodiment of the circuit configuration of a vibration monitoring device according to the present invention.01 Vibration circuit,
2 amplifier circuit, 3 level discrimination circuit, 6 peak hold circuit, 8 - reset circuit, 9, 10 display circuit.

Claims (1)

[Scope of Claims] 1) A device for monitoring the level of vibration of a structure during operation, comprising a circuit that detects vibration of the structure as an electrical signal;
a circuit for amplifying the detected electric signal; a level discrimination circuit for classifying the level of the vibration detected and amplified as the electric signal according to a plurality of reference levels set in advance in stages; a display circuit to which a signal of a reference level to which a vibration level belongs is input, and a display circuit that continuously holds the signal of the highest level or the peak value of the vibration level when a vibration belonging to the highest level among the plurality of reference levels appears; It is characterized by comprising a peak hold circuit for outputting and a reset circuit for returning the peak hold circuit to its pre-operation state, and displaying in parallel the highest level vibration that appears for a short time and the lower level vibration that appears constantly. Vibration monitoring equipment. 2) The device according to claim 1, characterized in that either the highest level vibration or the lower level vibration is displayed by lighting a light emitting body, and the other is displayed by blinking the light emitter. Vibration monitoring equipment. 3) A vibration monitoring device according to claim 1, characterized in that the reference level to which the vibration level of the structure belongs is displayed in different colors using light emitters.