RU53781U1 - VIBRATION DEFECTOSCOPE - Google Patents

Abstract

Belongs to the class of flaw detectors using sound and ultrasonic vibrations for diagnostics. With its help, it is possible to detect the presence of a defect in the material of the object in the area covered by the vibration sensors of the flaw detector. Or locate the defect

The flaw detector consists of an independent generator of vibrational vibrations, an analyzer block and vibration sensors connected to the analyzer block through a common connector.

A flaw detector kit can include from one to three groups of sensors, structurally designed as:

- individually attached to the surface of the diagnosed object sensors having vacuum, magnetic or other means of temporary fastening;

- groups of sensors mounted on a common frame or other common basis and installed simultaneously on the surface of the object;

- "head", moved in the process of diagnosis on the surface of an object containing several sensors.

In the process of the diagnostic procedure, a group of individually attached sensors or a group of sensors fixed on a common basis are superimposed on a controlled surface. The generator excites vibrational vibrations in the material of the object. The block analyzer compares the sensor signals and reports the presence or absence of defects in the area covered by the sensors, the surface of the object.

If it is necessary to determine the location of the defect, a “head” with sensors is connected to the analyzer unit, oscillations in the material of the object are excited by the generator. Moving the "head" on the surface of the object, they catch the moment when the block analyzer displays a message about the presence of a defect. The location of the “head” at this point will indicate the location of the defect.

Description

Belongs to class G 01 N 29 / 04-29 / 14 "Defects, detection by means of sound and ultrasonic vibrations".

In this class, flaw detectors using vibrational vibrations to determine the location of a defect are widely represented. (See Pavros S.K. "Ultrasonic methods and apparatus for the control of plate products." Technical acoustics. M. Engineering. 1992 T.1. Issue 2., RU No. 2231783 C2 7 G 01 N 29/04, RU No. 2206888 C1 7 G 01 N 29/04, etc.)

These flaw detectors, as a rule, have a scanning head containing an oscillation generator and a sensor - oscillation receiver. The location of the defect is determined by the reflected vibration signal in the process of moving the scanning head on the surface of the investigated object.

However, in some situations, it is important to determine not so much the location of the defect (through a lengthy search procedure) as the fact of the presence of the defect in the product. For example, in order to reject it.

The flaw detector presented in this application, which is the development of the utility model RU No. 47106 U1 G 01 N 29/04 Narimanov MV, Narimanov TV, can solve this problem. "Vibration system for monitoring the state of the object."

The bottom line is as follows. A group of vibration sensors is installed on the surface area of the object in which it is supposed to control the appearance of defects. A vibration generator in the material of an object vibrates. The installed sensors perceive vibrations propagating in the material from which the object or its investigated part is made. The signals from the sensors are sent to a block analyzer, in which they are compared with each other (by analog means or software on the microcontroller after converting the signals from the sensors to a digital representation using an ADC).

If there are no violations of material continuity (defect) in the studied area, the signals from the sensors will be approximately the same. If there are cracks, shells, or other discontinuities in the material under study, the propagation of vibration waves in the area where the sensors are installed will not be uniform, since these defects are an obstacle to the propagation of vibration waves. The signals from the sensors will not be the same, which will fix the block analyzer and report the presence of a defect.

Of course, in reality, the signals of the sensors can vary in the absence of defects. The reasons may be different: the difference in contact with the surface of the object, the difference in the actual characteristics of the sensors, the features of the configuration of the object, and so on.

In order to avoid the influence of reasons not caused by the presence of a defect, the sensor signals are balanced. In the initial state, the sensors are installed on a surface area without defects. They create vibrational vibrations in the material. Using the analyzer block, the sensor signals are compared with each other. If they are different, they are aligned, by multiplying by weights.

Weights for the sensor signals can be entered using analogue compensators (amplifiers with adjustable gain, potentiometers, etc.). Or, in the case of converting the sensor signals using the ADC to a digital representation, by software (on the microcontroller).

In addition, in order to cut off the insignificant reasons for the divergence of signals, in addition to balancing, a threshold is introduced for the divergence of the sensor signals. And only if the difference between the compared sensor signals exceeds the set threshold, a message is issued indicating the presence of a defect. The message may be displayed as

indication, sound, or electrical control signal to control other devices.

The functions of the threshold element can be implemented by analog means (for example, using a comparator, on one input of which the result of the comparison is supplied, and on the other - the set signal from the potentiometer). Or software (on the microcontroller).

The flaw detector sensors, in contrast to the RU No. 47106 U1 system, touch the surface of the test object only for the duration of the diagnostic procedure, when the presence or absence of a defect is detected (violation of continuity in the material covered by the sensors on the surface of the object).

At the same time, each sensor from the group can be installed individually on the surface of the object (on vacuum suction cups, magnetic, etc.).

Or immediately the whole group, if they are fixed on some frame or other common basis. Which, perhaps, makes sense when the objects of the same series of the same type are controlled.

In addition, it is possible that several sensors (two to four) can be assembled into one “head”, in which each sensor is separated from the adjacent insulating partition (in order to reduce the influence of the sensors on each other). Moreover, the sensors must be assembled in such a way that their sensitive surfaces, perceiving vibrational vibrations from the object, are in contact with the surface of the object at the same time as one sensitive element (aligned and rigidly fixed). Using such a “head”, moving it along the surface of the object, it will be possible to determine the location of the defect.

In principle, a flaw detector can include all three of these groups of sensors or some of them. In this case, all groups of sensors must have the same part of the connector in order to connect to the same connector on the analyzer block (see Fig.).

FIG. - The block diagram of the "Vibration flaw detector", on which:

- 1 - sensors

- 2-1 - the direct part of the connector of the sensor group or "head",

- 2-2 - the counterpart of the connector (for a group of sensors or "head") on the analyzer block (input connector),

- 3 - block analyzer,

- 4 - generator of vibrational vibrations.

After connecting a group of sensors or a “head” to the analyzer unit, the switch on the analyzer unit sets the appropriate mode, taking into account the number of sensors involved, since the number of sensors in the group or “head” can be different and the analyzer unit must process the information received through the input connector, only from sensors involved.

A variant with automatic tuning of the analyzer block to the operating mode, taking into account only the involved sensors, is possible. To do this, you need to poll the presence of signals on the contacts of the input connector. For example, using a sensitive trigger circuit (if necessary, having an amplifier and a driver before the installation input), triggered by a pulse. And in the case of digital processing of information from sensors, check the difference from zero value of the information received from each contact of the input connector.

After determining the presence of signals at the contacts of the input connector, the analyzer block can switch to the processing of information only from the sensors involved.

Sensor signals can be balanced from time to time or before a cycle of diagnostic procedures. To do this, the sensors are installed on a surface that is known to be free from defects, feed oscillations from the generator, and balance by inputting the corresponding weight coefficients.

After that, you can proceed to the diagnosis.

The diagnostic procedure is as follows. Sensors are installed on the surface of the controlled object (each individually or immediately a group of sensors fixed on a common basis) and vibrations are excited in the material of the object by the oscillator. If the controlled part of the object has no discontinuities in the material, the balance during the diagnostic procedure is not violated. The block analyzer reports that there are no defects.

The presence of discontinuities in the material of the controlled area leads to an imbalance in the signals of the sensors and the block analyzer gives a message about the presence of a defect.

Control of serial products can be carried out as follows.

Vibration sensors are installed on the surface of the control (serviceable) serial product. The oscillator is excited by the generator in the product. The sensor signals are balanced. Next, proceed to the procedure for monitoring the next batch of products of this series. To do this, vibration sensors are installed sequentially on each product (at the same points as on the control product during balancing). A generator (which is installed at the same point as during balancing) excites vibrations in the product. The block analyzer displays a message about the presence or absence of a defect.

If several sensors are assembled in one "head", the distance between them is insignificant (equal to the thickness of the insulating partition between them). For this reason, the difference in the signals of the sensors of the "head" (imbalance) can occur only when the "head" is located above the place of violation of the continuity of the material (over the defect). This makes it possible, by moving the "head" with several sensors on the surface of the object, to determine with its help the location of the defect.

Having in the set of the flaw detector a group of sensors placed over the area and the “head”, it is possible to solve two problems with one flaw detector:

- diagnose the presence of a defect in a certain area,

- locate the defect.

The technical result of the proposed utility model is the creation of a new tool from the arsenal of flaw detectors using sound and ultrasonic vibrations, with the ability to diagnose the presence of a defect in a certain area and, if necessary, determine the location of the defect.

Claims (1)

Vibration flaw detector, consisting of an independent generator of vibrational vibrations, two or more identical vibration sensors and an analyzer unit, having: compensators, a comparison unit, a threshold element; or: analog-to-digital converters and a microcontroller; and also having means for outputting the result of the flaw detection in the form of a control electric signal, light indication or sound signal, characterized in that the vibration sensors connected through a common connector to the analyzer block have three types of design: vibration sensors individually attached to the surface of the diagnosed object, having vacuum, magnetic or other means of temporary fastening; in the form of a group of vibration sensors mounted on a common frame or other common basis; in the form of a “head” that is moved during the diagnostics along the surface of an object containing several vibration sensors separated by insulating partitions and assembled in such a way that their sensitive surfaces, perceiving vibrational vibrations from the object, are in contact with the surface of the object at the same time.