RU159781U1 - DEVICE FOR INCREASING THE SENSITIVITY LEVEL DURING TIGHTNESS CONTROL BY A NON-CONTACT ACOUSTIC GAS METHOD AND CALIBRATION OF THE LOWER THRESHOLD OF OPERATION OF THE LEAF DIGITAL EQUIPMENT - Google Patents

Abstract

1. The amplifier and driver of the acoustic field of the through defect - air ultrasound during the expiration of the control gas jet, while ensuring the conversion of the shape of the front of the acoustic field to a shape close to spherical, made in the form of a mesh structure. 2. The amplifier and driver of the acoustic field of the through defect according to claim 1, which is used as an expanded mesh. 3. The amplifier and shaper of the acoustic field of the through defect according to claim 1, which is used as a net of plain or twill weaving. 4. The amplifier and driver of the acoustic field of a through defect according to claim 1, which is a grid of metal, polymeric materials, or fabric with a pile. 5. A control leak to verify the threshold sensitivity of the leak detection equipment and the non-contact acoustic gas method at a distance, ensuring the use of an amplifier and acoustic transformer of the through defect according to claim 1, which is a device containing a housing with a gas inlet, tightly connected to a removable insert with a critical verified micro-nozzle, which is a gas outlet by means of a clamping nut, in which fastenings of fixing strips are provided, which ensure the fixation of the mesh con structure of the contact surface of the control leakage insert. 6. The control leak according to claim 5, characterized in that the mass flow rate characteristic of the critical micro-nozzle being verified is a measure for calibrating the leak detection equipment and the non-contact acoustic gas method at a distance based on the flow area of the calibrated critical micro-nozzle and the temperature

Description

DEVICE FOR INCREASING THE SENSITIVITY LEVEL DURING TIGHTNESS CONTROL BY A NON-CONTACT ACOUSTIC GAS METHOD AND CALIBRATION OF THE LOWER THRESHOLD OF OPERATION OF THE LEAF DIGITAL EQUIPMENT

State of the art

A known method of passive control of tightness [1]. When monitoring using this method, a parabolic amplifier of the acoustic field of the leak with a means of recording the acoustic signal fixed in the focal length of the parabolic antenna is used as a part of the monitoring means. In this case, the signal from the sensitive element of the parabolic antenna is analyzed using a computer system and, thus, the monitoring of operating equipment for leakage by the presence of an acoustic leak signal is ensured. This method allows remote tightness control to ensure personnel safety during monitoring, but the disadvantage of this method is that the method is not calibrated using control leaks that verify the low threshold of sensitivity of leak detectors and the tightness control method itself using additional contact amplifiers of the acoustic defect field . At the same time, it must be understood that the front of the acoustic field of the through defect has a complex uneven shape, i.e. when testing in this way, it is possible to obtain a false picture of the location of the through defect.

Known methods for determining the location of the leak and acoustic leak detectors for their implementation [2, 3, 4], in which amplifiers of the acoustic field are used horns connected to sensitive elements, and [4] allows to increase the accuracy of determining the location of the leak by illuminating it with a light beam combined with the maximum of the ultrasonic signal in which the transducer and the light source installed behind it are located along the axis of the horn. At the same time, a film of reflective material is applied to the inner surface of the horn. When checking the tightness of products, the leak location is determined by the intersection of the longitudinal axis of the acoustic transducer with the surface of the test object at the time of recording the maximum of the ultrasonic signal arising from the turbulent gas outflow through the through defect. The disadvantage of these methods, allowing the tightness control to be carried out at a remote distance, is that the sensitivity of the methods does not allow tightness control to be carried out at a distance that ensures safe testing, which can reach tens of meters. It should also be noted that the front of the acoustic field of the through defect has a complex non-uniform shape, and the free (diffuse) specified acoustic field becomes at a distance from the defect, often exceeding the sensitivity threshold of this method, i.e. when testing in this way, it is possible to obtain a false picture of the location of the through defect, while the lower threshold of the sensitivity of the method is not calibrated using additional contact amplifiers of the acoustic field of the defect, which further complicates the detection of through defects.

There is a method of amplifying the acoustic field of a defect consisting in the use of surfactants that are contacted on the surface of the test object and in the place of the through defect create an effect of amplification of acoustic pressure in the entire frequency range at which the acoustic energy of the signal is released during the flow of the control medium through end-to-end defect. These surfactants are described in [5], and their use in the process of an acoustic gas leak tightness control method allows to increase the safe distance to the test object during testing, however, the shape of the acoustic field front remains complex irregular shape, which negatively affects the process localization of the leak. It should also be noted that the lower threshold of the sensitivity of the method is not calibrated using additional contact amplifiers of the acoustic field of the defect, which complicates the identification of through defects.

Known [6] is an acoustic leak detector containing a housing with a sensing element and a turbulator combined with it, in which, in order to increase the sensitivity of the leak detector, the turbulator is made in the form of a resonant block consisting of a series of parallel rectangular metal plates which are fastened between their average transverse axes between by means of a comb made of insulating material. The sizes of the plates are selected from the condition of equality of their own resonant frequency to the working resonant frequency of the sensitive element. In the process of using this device, in the presence of a leak from the test object, a gas stream flows to the pointed ends of the rectangular plates of the turbulator, which swirls and creates an acoustic field at the resonant frequency of the sensing element. The acoustic energy of the signal is converted by the sensing element into electrical voltage, which is amplified and recorded.

The method allows to increase the sensitivity of the tightness control by the acoustic gas method, however, the disadvantage of the method is that its use at a remote distance, ensuring safe testing is difficult due to the need to turbulence the flow of the control medium in the immediate vicinity of the control object. This circumstance negatively affects the safety of operators conducting leak testing.

Known receivers of ultrasonic leak detectors, including turbulators in the form of springs and gratings with conical holes [7, 8, 9]. These devices provide amplification of the acoustic field of the defect, but are combined with receivers of acoustic vibrations, and their use at a remote distance, ensuring safe testing, is difficult due to the need to turbulence in the immediate vicinity of the test object, which does not ensure the safety of nondestructive testing personnel conducting leak detection.

Known acoustic leak detector [10] in which the acoustic field of the defect is enhanced due to the fact that the sensitive element of the leak detector structurally contains adjacent layers of polymer fabric, consisting of interwoven threads with a pile, which are located in front of the sensitive element parallel to its working surface . With this method, the flow of the control gas exiting through the through defect in the test object vibrates the villi of the polymer threads, which, when interacting with each other, create an additional acoustic field recorded by the receiver. This method provides an increase in the intensity of the acoustic field of the defect for laminar jets, i.e. for jets of small flows of the control gas not creating an ultrasonic defect field. In this case, leak detection is only possible in the immediate vicinity of the sensitive element of the leak detector from the control object, and its use at a remote distance, ensuring safe testing, is not possible, because the design [10] does not provide elements for attaching polymer threads to the control object. At the same time, polymer threads do not provide the required structural rigidity for the purpose of leveling the complex shape of the front of the acoustic field of the defect for the turbulent nature of the outflow of the control gas (for more powerful flows of the jets of the control gas), which reduces the likelihood of finding a through defect when monitoring at a remote safe distance. It should also be noted that during the testing process, the use of polymer fibers is limited by the possibility of their rapid destruction during testing, and the low probability of interaction of the control gas jet stream with the threads in case of using one layer of polymer fibers may not provide the required reliability of tightness control, which is especially important for hazardous industrial facilities operating under pressure. This device is taken as a prototype.

A known method of monitoring the tightness of products [11] in which the control object is filled with the test pressure of the control gas, while the controlled surface area is blown with one or more laminar air jets that do not intersect with each other. When a technological laminar jet (on the surface of the control object or in the space above it) meets the laminar jet of the control gas emerging through the through defect in the control object, forced turbulization occurs and a source of ultrasonic vibrations arises, which are then fixed by the ultrasound receiver and, on the basis of this, the tightness of the object is judged control.

This method provides an increase in the intensity of the acoustic field of the defect for laminar jets, i.e. for jets of small flows of the control gas that do not create an ultrasonic field of the defect, however, its use at a remote distance, ensuring safe testing, is difficult due to the need to turbulence in the immediate vicinity of the test object, thereby not ensuring the safety of testing. In addition, under conditions when the control gas stream provides the formation of an ultrasonic field, the method does not equalize the complex shape of the front of the acoustic field, thereby reducing the likelihood of detection and localization of the through defect.

Known diffusion leak [12], to configure the leak detection system, comprising a housing with input and output channels, with a support band made in it, on which a permeable membrane is hermetically fixed by a pressure ring element. In this case, the control leak is provided with a gas condenser, the hole in which is made in the form of a capillary, which is installed between the clamping ring element and the permeable membrane on its contact surface. This device contains elements for calibration using contact means of the amplifiers of the acoustic field of the defect. However, the disadvantage of this device is that the calibration of the acoustic gas method is limited by the coarse flow of control gases, which this device cannot reproduce due to the diffusion nature of the expiration of the control gas, thus, the formation of an ultrasonic acoustic field of the defect generated by the turbulent flows of the control medium is not ensured. It should also be noted that although this control sample provides for the possibility of using the surfactants described in [5], it is not possible to measure the thickness of the applied coating without the use of additional measuring tools (coating thickness gauges), which negatively affects the efficiency of the control, t .to. the consumption of these substances (having different chemical composition) during the testing process is determined based on the instructions for use and, ultimately, is determined by the thickness of the coating applied. In addition, the design of the specified control sample does not provide for the use of contact means for amplifying the acoustic field of the defect and changing the complex shape of its front-mesh structures described in this patent (listed below). It should also be noted that the design of this control sample does not provide for the possibility of measuring the temperature of the control gas in front of the membrane through which the control gas, helium, diffuses. This device is taken as a prototype.

A known method for determining the size of the leak [13], relating to the control of the tightness of products by contact acoustic method. This method allows to increase the accuracy of determining the equivalent diameter of the leak by measuring the intensity of acoustic radiation from the flow of liquid through the leak. The indicated radiation intensity is determined by measuring the wall thickness of the product in the leak, dynamic viscosity, fluid density, the speed of sound propagation in the fluid, the pressure at the inlet and outlet of the leak, as well as the distance from the leak to the receiving transducer. A receiving transducer measures the intensity of acoustic signals from a leak. Based on the measured values, the equivalent leak diameter is determined. The disadvantage of this device is that it is applicable for control liquids, and does not provide calibration of the non-contact acoustic gas method using control means used on the contact test surface and providing amplification of the acoustic field of the defect.

A known method of monitoring the tightness of products [14]. This invention relates to the control of tightness of products by the acoustic method and allows to expand technological capabilities by determining the geometric dimensions of the leak. Gas is supplied to the controlled product and a test pressure is created in it. Then measure the temperature and dynamic viscosity of the gas. Using a sensitive element of the measuring equipment scan the controlled surface of the product. When an acoustic signal is fixed by measuring equipment, the minimum distance from the leak point to the sensing element is measured. The equivalent leak size is determined from the relationship establishing the relationship between the leak parameters and the physical properties of the gases used, the test conditions and the minimum distance from the leak at which acoustic vibrations are recorded. The disadvantage of this method is that it does not ensure the safety of testing, because the specified minimum distance at which the acoustic receiver captures the acoustic field of the defect may be less than required by safety measures. In addition, in the process of calibrating the leak detection equipment and the method of tightness control, it is not possible to use the monitoring means to enhance the acoustic field of the defect used on the contact surface of the test object.

A known method of monitoring the tightness of products [15], in which a reference sample with a calibrated hole is filled with process fluid and increase its pressure. Using a piezoelectric receiver mounted on the product, the appearance of acoustic vibrations arising in the sample material during the flow of a fluid, during which acoustic vibrations occur, is recorded. Using the known area of the calibrated hole and the fixed minimum pressure, the equivalent area of microdefects is determined. The disadvantage of this method is that it is applicable to a method for monitoring tightness using acoustic emission (with the contact surface of the object of control by placing acoustic transducers), while the method is not suitable for a non-contact acoustic gas method, due to the fact that it is designed to determine acoustic waves, generated by the control medium - liquid in the material of the control object (for example, in steel) and is not intended to determine the acoustic waves propagating in the air the ear (with a significantly higher attenuation coefficient) when generating the acoustic field of the defect by gas jets, taking into account the different spatial positions of the control gas jet emerging from the micro-nozzle of the control leak, and using existing means of amplifying the acoustic field of the defect used on the contact surface of the control object. At the same time, it must be understood that the direction and shape of the acoustic field of the defect propagating in the air (outside the material of the control object) does not matter during the acoustic emission control, because the location of the defect is determined by calculating the correlation coefficient from signals coming from several microphones installed motionlessly (usually with acoustic contact through contact liquids) on the surface of the test object, but are of great importance for the non-contact acoustic gas method. It should also be noted that in this control sample the possibility of using surfactants described in [5] is not provided. the consumption of these substances (having different chemical composition) during the testing process is determined based on the instructions for use and ultimately is determined by the thickness of the coating applied. In addition, the design of the specified reference sample does not provide for the use of contact means to amplify the acoustic field of the defect and change the complex shape of its front described in this patent (listed below). In addition, it should be noted that in the process of tightness control, the location of the defect location (the spatial direction of the control gas stream leaving the defect location) is important, because when the acoustic wave is reflected from any obstacle (inevitably present in the control zone), the signal may give a false indication. Reliability of defect localization requires full-scale tests taking into account the different directions of the control gas stream emanating from the micro nozzle. At the same time, the technology of tightness testing by the non-contact acoustic gas method involves scanning the probe of the acoustic leak detector of the surface of the test object at a remote distance, while the spatial location of the defect and the shape of the acoustic field of the defect are generated by it, especially when using contact amplifiers of the acoustic field of the defect (since the surface - active substances can simply drain off the surface of the control sample during the calibration of the leak detector equipment). These circumstances require the development of a control sample for the non-contact acoustic gas method, which would ensure any spatial position of the defect and during the calibration process would ensure the full-scale testing for reliable localization of through defects (test gas leaks) and their subsequent repair.

The objective of the group of inventions is to develop a device for a non-contact acoustic gas method of tightness control, which allows the formation and amplification of an acoustic signal - air ultrasound in a wide range of flow rates of control gas jets emerging from a through defect, which allows for remote testing to ensure their safety, as well as improving the reliability of the location of the leak of the control gas. Another objective of the group of inventions is the development of a calibrated control leakage device that allows calibration of the lower threshold of sensitivity of leak detection equipment and the non-contact acoustic gas method of tightness control using contact amplifiers of the acoustic field of a through defect as a means of tightness control used in pneumatic tests, which ensures increased reliability of the location of the leak test gas at a remote safe distance due to increase the accuracy of determining its value.

Brief Description of the Figures

In FIG. 1a is a flow chart of a leak test, a non-contact acoustic gas leak test method that allows pneumatic testing at a remote distance, in the case when the working axis of the microphone system coincides with the axis of the sound beam of the acoustic field of the defect, including: 1 - control object - pipe with flange connection, 2 - test gas flow in a flange connection, 3 - acoustic ultrasonic defect field with front of an irregularly shaped acoustic wave, 4 - operator with by an oral leak detector, 5 - an acoustic signal amplifier for a leak of a parabolic type with a sensor fixed in the focus of the parabola, 6 - a laser leak detector, 7 - an axis of direction of flow of the control gas emerging from the through defect, coinciding with the axis of the acoustic beam of the front of the acoustic field of the defect, 8, 9 - coordinate axes, 10 - schematically shows the cut shape of the front of the acoustic wave. The case is shown when the direction of the axis of the control gas jet emerging from the through defect and the axis of the acoustic beam coinciding with it is located perpendicular to the axial line of the explosive test object. Also shown schematically is the distance L1 from the point of the through defect to the operator.

In FIG. 16 is a flow chart of leak testing, a non-contact acoustic gas control method, during which the working axis of the microphone system coincides with the direction of the maximum sound pressure of the acoustic field of the through defect with a complex shape front. The figure also schematically shows a graph of the acoustic pressure drop of the acoustic field of the through defect versus the distance between the operator and the control object in the absence of contact amplifiers of the acoustic field of the defect. The figure also schematically shows a graph of the decrease in acoustic pressure from the distance between the leak and the operator. Also presented is the distance L2 between the operator and the test object, and 31 is the angle α between the working axis of the microphone and the axis of the acoustic beam of the defect field.

The dimensions of the analyzer, the test object and the acoustic field shown in FIG. 1a, 1b, do not correspond to the real ones, which was done in order to facilitate perception.

In FIG. Figure 2a shows a diagram of tightness control without using contact means to strengthen the acoustic field of a defect, including: 12 - a test object, 13-rod filling tube, 14 - a test gas cylinder, or other means providing a control gas pressure in the test object, 11 - a through defect main material or welded joint, 10 - schematic representation of the acoustic field of the defect with a front of complex shape.

In FIG. 2b presents a diagram of the tightness control using contact means for amplifying the acoustic field: 16 — mesh structure (turbulator), 32 — schematic representation of the shape of the front of the acoustic field of the defect.

In FIG. Figure 3a shows a diagram of the tightness control using: 13 - plug-in filling tube, 18 - control leakage assembly, 30, 33 - gas valves.

In FIG. Figure 3b shows a graph of the test pressure of the control medium versus time during pneumatic testing and determination of the threshold sensitivity of leak detectors and the acoustic gas leak test method.

In FIG. Figure 4 shows a control leak (isometry) for checking the lower sensitivity threshold of the acoustic gas method, which contains: 18 - control leak assembly, 20 - inlet channel, 22 - clamping nut. The figure also shows the lines AA ′ and BB ′ defining the cutting plane of the specified control leak, to explain the operation of the device.

In FIG. 5a shows a control leak to check the lower sensitivity threshold of the acoustic gas method in the cut plane containing lines AA ′ and BB ′ (Fig. 4), containing: 19 — the body of the control leak, 20 — the input channel, 23 — the critical calibrated micro nozzle made in the insert - 25, 22 - clamping nut, 21 - sealing element, 24 - calibration tank made in the clamping nut, 35 - device for measuring control medium parameters in front of the nozzle with an indication device.

In FIG. 56 is a part of the control leak for checking the lower sensitivity threshold of the acoustic gas method, explaining the operation of the device and containing: 22 — a clamping nut, 23 — a critical calibrated micro nozzle made in the insert — 25, 24 — a calibration measuring capacitance made in the nut, 26 — an indicator scale with risks for determining the level and volume of liquid poured into the calibration tank, providing the required level of contact liquid filling to enhance the acoustic field.

In FIG. 5c shows a control leakage element (top view) for checking the lower threshold of sensitivity of the acoustic gas method, comprising: 22 — a clamping nut, 23 — a critical calibrated micro nozzle made in the insert — 25, 24 — a calibration measuring capacitance made in the nut, 27 — a mesh element , 28 - clamping strips for fixing the mesh element, 29 - fixing screws.

Disclosure of invention

The specified task of the group of inventions is solved due to the fact that in the process of conducting pneumatic tests while checking the tightness by the non-contact acoustic gas method, the main factor is determined by the safety of specialists conducting a search for through defects during pneumatic testing. This parameter — L1 shown in FIG. 1a is calculated according to [21, 22] according to the formulas:

where R _Osk - radius of the expansion of fragments in the explosion of pipelines in case of emergency, m; p is the pressure in the pipeline, MPa (at the time of testing), k is the coefficient taken 15.3 for pipes in which the ratio of diameter to wall thickness is 100. For pipes with a nominal diameter of less than 700 mm, the ratio of diameter to wall thickness ranges from 40 up to 80. For this case, the numerical coefficient is taken equal to: 4 - for pipelines with a diameter of up to 300 mm; 10 - for pipelines with a diameter up to 500 mm; 11 - for pipelines with a diameter of more than 500 mm.

This factor is determined as for example, for gas monitoring objects during pneumatic tests, in the event of an accident, fragments can form with a span of up to 40 m (pipe diameter - 1 m, thickness of the base material - 5 mm, test pressure 20 kG / cm ² ). Testing at this safe distance is complicated due to the fact that airborne propagation (air ultrasound) with a predominant frequency of 40 kHz, which is generated by the flow of the control substance exiting through the through defect in the test object with increasing distance from the defect to the receiving transducer, quickly attenuates . The values of sound pressure attenuation in air calculated according to [27], for example, for normal conditions and ƒ = 40 kHz, are α = 1.3445 dB / m, thus, at a distance of 40 m the level of acoustic pressure drops tens of times, without taking into account absorption of sound vibrations that are generated by dissipative losses. In this case, the use of non-contact amplifiers of the acoustic field of the defect described in [1-4, 6-10] will not lead to amplification of the acoustic field of the defect and, therefore, to its localization due to the fact that in most cases there will simply be nothing to amplify at the indicated distance. In addition, the shape of the front of the acoustic field of the defect is uneven and has the so-called “silence cone” [26], this fact is illustrated in FIG. 1a, in this case, in FIG. 1b shows the case when during the pneumatic tests the working axis of the microphone system coincides with the direction of the maximum sound pressure of the acoustic field of the through defect, while the distance L2 = L1 / cosα increases even more than the distance L1, which leads to an even greater attenuation of the acoustic pressure amplitude defect fields. This circumstance negatively affects the sensitivity of the tightness control, since when the direction of the sensitive element (the working axis of the microphone system) is strictly in the direction of the turbulent leak stream (Fig. 1), the operator will not get a reliable picture of the location of the defect. This circumstance is even more pronounced in the case of limited control suitability of the control object when a sound wave is reflected, for example, from the ground. The theoretical background for the implementation of this method has been studied for a long time, and is given in [16, 17].

To compensate for losses in the amplitude of sound pressure and the intensity of acoustic ultrasonic vibrations of the defect field and for solving the problems of the group of inventions, it is proposed to use steel and polymer mesh structures consisting of one or more layers of mesh placed on the contact surface of the test object (Fig. 2b). These mesh constructions made of expanded metal mesh or twill weave play the role of a turbulator at low flows of the control medium (which do not ensure the formation of an ultrasonic field of the defect) and provide the formation and amplification of the ultrasonic field of the defect. For understanding purposes, we can compare the effect of the appearance of airborne ultrasound when a jet of control gas passes through a mesh structure of a laminar stream with a simple ultrasonic whistle. The background to this invention for laminar flows of a control medium is described in [18, 19, 20]. In this case, the laminar flow of the leak, passing through the cells of the mesh structure, is divided into several flows, which, interacting with each other, form a reinforced ultrasonic field (air ultrasound) similarly [11], and can be fixed by a sensitive element at a distance ensuring the safety of pneumatic tests according to . 1. For the case of turbulent flows, the prerequisites for the implementation of this control method are given in [16, 17]. From these works it follows that the formation of air ultrasound for turbulent flows does not occur in the entire jet, but in the zone of the control gas jet, which is located on the edge where air ultrasound (at frequencies of 35-45 kHz) is formed in the zone of transition from turbulent to laminar mode flow stream. This circumstance determines the formation of a “silence cone” (Fig. 1), which is reflected in chapter 4 [16] and [26], and allows us to correlate the surface area of the acoustic wave front with the acoustic field parameters of the defect. In this case, in the case of applying a mesh structure, the turbulent flow of the control gas is divided into several flows, which ensures an increase in the indicated area of the formation of air ultrasound by now several jets of control gas and a change in the shape of the front of the acoustic field due to the superposition of these acoustic fields. The specified generated and amplified acoustic field can be fixed at a distance without the need to be in the immediate vicinity of the control object.

This method, in contrast to those described in [7-10], in which the acoustic signal sensors are combined with different designs of turbulators, provides for monitoring by the non-contact acoustic gas method at a safe distance described above.

Opening the described control method in more detail, it can be noted that in the case of a turbulent flow emerging from the through defect in the control object, the mesh structure acts as an amplifier of the acoustic leak signal, due to the splitting of the control medium flow, with the formation of several flows. At the same time, during the interaction of these flows, the acoustic signal of the leak is amplified several times; in addition, in the case of mesh structures, the complex funnel-shaped shape of the acoustic front of the defect field changes, ensuring its change to a shape close to spherical (Fig. 2b), due to the fact that the creation of acoustic vibrations by the gas flow is due to the turbulence of its motion. A stream of gas flowing through a leak has several zones, namely: a section of laminar motion directly at the outlet of the leak and turbulent at some distance from the outlet. The source of acoustic signals from the leak is turbulence, which owes its appearance to a jump in velocities at the boundary of the jet and the surrounding gas, creating a “silence cone” inside the jet stream. The use of mesh structures provides physical fragmentation of the control gas flows, thereby creating a turbulent region of intersecting jets of control gas and transforming the complex shape of the acoustic field of the defect containing the "silence cone" into a shape close to spherical. Thus, a technical result is achieved - improving the reliability of the search for leaks at a safe distance (Fig. 2A, 2B). Moreover, the achievement of this technical result is achieved to a greater extent due to the use of mesh packets used on the contact surface of the test object (providing contact using fasteners (34 - Fig. 2b, 28 - Fig. 5c)) by increasing the probability of interaction of the control gas jet out through the defect and the material of the mesh bag.

The use of these mesh structures removes the uncertainty in the process of measuring the parameters of the acoustic field of a defect at a remote distance using leak detection equipment due to the alignment of the shape of the acoustic front and its approximation to a spherical one in the case of a turbulent flow of control gas.

Thus, the reliability of detecting leaks using contact amplifiers of the acoustic field of the defect - mesh structures provides not only the formation and amplification of the acoustic field of the defect in the case of a laminar flow of the leak, but also the alignment of the complex shape of the front of the ultrasonic wave generated by the flow of the control medium in the case of a turbulent flow. The use of these devices provides a solution to the tasks of the group of inventions in terms of reliable localization of the through defect at a safe distance. An additional factor ensuring the strengthening of the defect field is the mesh structures used by the contact surfaces of the test object, which are several grids stacked together. This technical solution is aimed at enhancing the acoustic field of the defect due to the additional splitting and turbulization of small flows of the control gas and increasing the likelihood of contact of the control gas stream with mesh elements.

In order to create a turbulization effect, it is possible to use mesh structures consisting of a mesh of metal, polymeric materials, or fabric with a pile used on the contact surface of the test object and mesh structures representing a combination of mesh of metal, polymer materials or fabrics with a pile. This technical solution allows combining the effect of turbulization of technological flows with the effect described in [5].

Also an additional factor when conducting leak testing by the non-contact acoustic gas method using mesh designs in order to increase the sensitivity level, as well as to more accurately localize the acoustic field of the defect, additional use of the acoustic field amplifiers of the defect described in [1, 2, 3, 4] combined with a receiver non-contact acoustic transducer, providing testing at a remote distance from the object of control.

Another objective of the group of inventions is to increase the reliability of localization of the leak point of the control gas at a remote safe distance by increasing the accuracy of determining its value. The problem is solved by the implementation of the control leakage device, which allows calibrating the lower threshold of sensitivity of leak detection equipment and the non-contact acoustic gas leak tightness control method using contact amplifiers of the acoustic field of the through defect described in [5] and using the mesh structures described above at a remote safe distance. This device provides the formation of control gas flows in a wide range of flow rates (turbulent and laminar flows) due to the use of a calibrated micro-nozzle in the design. It also provides any spatial position of the control gas jet, and with it, any situation can be realized in which an acoustic wave is reflected by the generated control gas jet to simulate limited control suitability in the process of testing the tightness control technology.

The prerequisites for the implementation of this device were undertaken in [16, 17], so in the 3rd chapter [17], control samples for the non-contact acoustic gas method, which are capillary metal tubes with different internal diameters, were developed and tested. The disadvantage of these control samples is that they cannot be metrologically verified, and their application does not provide calibration of the entire tightness control system [23], which includes not only the test object and leak detectors, but also the means of amplifying the acoustic field of the defect — mesh structures described in this patent , as well as non-contact means of amplification of the acoustic field of the defect described in [1-4, 6-11]. At the same time, as well as [12], these control samples do not provide contact deposition of surfactants with the required deposition level without using additional means of measuring the thickness of the applied coating. The elimination of these disadvantages is ensured by the implementation of the device is a control leak, the operation and device of which are given below.

The control leak is shown in FIG. 4. The operation of the device is illustrated in FIG. 3a and FIG. 3b, according to which, in the process of preparing the test object for testing, the control leak device is mounted through the inlet channel 20 of the leak housing of FIG. 2a into the gas line of the filling rod pipe 13 providing mobility of the device, while ensuring the unity of the characteristics of the control medium, which is loaded with the control object and the control leak. The pressure set in the test object during the tests according to [21] is carried out stepwise FIG. 3b. This circumstance, in preparation for control or in the process of conducting tests (in terms of checking the lower threshold of sensitivity) allows measuring the minimum recorded intensity of the acoustic field at a safe distance, calculated using [22] for the test pressure Risp of FIG. 3b. At the same time, in the process of pressure build-up in the first step section (interval T2-TK) of FIG. 3b, the acoustic pressure level is determined for the pressure in the test object P1, which is recorded using the receiving transducer at a distance calculated as safe for the test pressure according to formula 1, with or without contact acoustic amplifiers of the defect field (as determined by the control technology tightness). If during the pressure build-up in the first section the acoustic equipment did not register readings, a further increase occurs in accordance with the loading scheme of the test object. With a further increase in pressure (interval T4-T5) for the pressure level in the monitoring object P2, the operation to determine the acoustic pressure level at a safe distance determined by Risp is repeated until the non-contact acoustic transducer records the readings in units of the leak detector output scale (for example, mV ) The values (in units of the output scale of the leak detection equipment) at which the non-contact acoustic transducer fixes for the indicated pressure interval the dependence of the properties of the acoustic field of the defect on the pressure in the test object, taking into account all the applied amplifiers of the acoustic field of the defect, in accordance with which the threshold value of the test pressure is calculated at which the acoustic field of the through defect calculated by formula 2 was recorded in accordance with [21]. Thus, the calibration characteristic of the non-contact acoustic gas method is the dependence expressed in units of the mass flow rate of the control substance calculated in accordance with [24, 25] and passed through the critical micro-nozzle of the control leak during the calibration of leak detection equipment and the non-contact acoustic gas method using contact amplifiers of the acoustic field defect per unit time relative to the pressure of the control medium in the control object and the conditions of pneumatic tests in in accordance with formula 3, which is determined in accordance with [21, 23]. At the same time, for this calculation, a control unit for measuring the parameters of the control gas (pressure and temperature) indicated in FIG. 5a.

Where

P _min - threshold value of pressure in the control object, kPa;

P _n - pressure value in the control leak at which the microphone system of the leak detector detects the minimum level of acoustic pressure at a distance determined by f. 1 for test pressure Risp, kPa;

and _T is the signal of the microphone system from the control leak, mV;

and _f is the average background signal, mV;

a _Fmax and _Fmin - the maximum and minimum values of the background signal fluctuations,

Where

Q _min - threshold sensitivity of the leak detector, taking into account the real conditions of control, kg / h;

K ₁ - coefficient determined and verified for a particular micro nozzle with an inner diameter Dy;

P _min - threshold value of pressure in the control object, kPa;

T = 273, l + t ° - absolute temperature in front of the micro nozzle, ° C.

The described device is a control leak eliminates the disadvantages of the method specified as a prototype [12], as well as [13, 14, 15]. This device is designed to calibrate the non-contact acoustic gas method. The device provides the formation of acoustic waves propagating in the air (with a significantly higher attenuation coefficient than in the material of the test object) when generating the acoustic field of the defect by gas jets (with laminar and turbulent nature of the outflow), taking into account the different spatial positions of the control gas stream emerging from the micro-nozzle of the control leak, and using the amplification of the acoustic field of the defect - mesh structures described above and other existing means. The design of the specified reference sample provides for the use of contact means to amplify the acoustic field of the defect and change the complex shape of its front - mesh structures. The design of the control leak (Fig. 5a, b, c) containing the housing with the inlet of the control gas contains fasteners of mesh structures (mesh packets) at the outlet of the control gas, which is a calibrated micro nozzle made in the insert, hermetically connected to the body of the control leak by means of a clamping nut . It should also be noted that in this control sample, it is possible to use surfactants described in [5] with recording the thickness of their deposition without using additional means for measuring the coating thickness, by correlating the geometric parameters of the measuring capacitance with the formed clamping nut 22 (Fig. 5a , Fig. 5b.) with a through hole and an insert with a replaceable critical micro nozzle 25 (Fig. 5a), as well as the level of applied coating measured using an indicator scale with risks 26 (f of 5b.). The design of the specified reference sample provides for the use of contact means to amplify the acoustic field of the defect and change the complex shape of its front described in this patent. In addition, it should be noted that the design of the control leak during the leak test provides the ability to change the location of the defect (the spatial direction of the jet of control gas exiting the defect), and simulate the reflection of the acoustic wave from any obstacle (inevitably present in the control zone), thereby eliminating the possibility of a signal giving a false indication. Calibration of the lower threshold of the leak detection equipment when using a control leak provides reliable localization of the defect during field tests, taking into account the different directions of the control gas stream emanating from the micro nozzle. The development of the technology for tightness testing by the non-contact acoustic gas method using a control leak provides reliable detection of control gas leaks when scanning the acoustic leak detector of the surface of the test object at a remote distance, while providing accurate on-site modeling of the shape of the acoustic field of the defect and the spatial location of the defect as when applying a surface active substances and mesh structures described above (if provided x reliable fixation of FIG. 5c). The design of the control leak includes a container made in the clamping nut 22 (Fig. 5A, Fig. 5b.). In addition, for testing with the use of additional contact amplifiers, for example contact liquids, a risk indicator bar 24 is provided in the tank 24, which ensures that the contact liquids are filled in strict accordance with the instructions for use of these contact liquids. It should also be noted that the control leak for the non-contact acoustic gas method provides any spatial position of the defect for reliable localization of through defects (control gas leaks) and their subsequent repair, because in the control leakage circuit, fixing strips are provided for fastening contact mesh structures (Fig. 5c).

The use of mesh structures in the process of pneumatic testing and calibration of the non-contact acoustic gas method using the specified control leak and mesh structures placed on the contact surface of the leak as a control object improves the accuracy of measuring the size of the leak at a remote distance due to the alignment of the shape of the acoustic front of the defect and the removal of uncertainty during measurement characteristics of the acoustic field of the defect, which makes it possible to correlate the flow characteristic of the leak parameters of the acoustic field through the defect. Evaluation of the acoustic pressure or the intensity of the acoustic field aligned with the mesh structures on the control leak and on the control object allows us to correlate the flow characteristics of the replaceable verified micro nozzle with the acoustic characteristics of the acoustic field of the defect at a remote distance, which is a new technical result aimed at increasing the reliability of the location of the leak and increasing the estimate of its magnitude. Also, a new technical result of the group of inventions is to increase safety when conducting leak testing by the non-contact acoustic gas method by using mesh structures as turbulators of laminar leakage flows in terms of increasing the sensitivity of monitoring. This circumstance makes it possible to reduce the pressure of the test gas during testing and to carry out the control and calibration of the leak detection equipment during the pneumatic tests for the acoustic gas method at a minimum distance from the test object to the probe of the ultrasonic leak detector, according to [23]. Thus, a new technical result is achieved - improving safety and improving manufacturability in the process of tightness control due to the fact that the design of leak detector analyzers is simplified, since the use of laminar flow flow turbulators is not required and the safety condition for conducting pneumatic tests is ensured, which is especially important for control objects in which it is impossible to create a high pressure of the control gas. This circumstance allows us to expand the applicability of the non-contact acoustic gas method of tightness control.

Thus, the application of the group of inventions solves the problem. Industrial applicability

The claimed devices for increasing the sensitivity level when checking the tightness by the non-contact acoustic gas method and calibrating the lower threshold of the leak detection equipment during the pneumatic testing are industrially applicable and tested on the TI1-SOND leak detection system and the KT-2 ACOUSTICS control leak allowing to monitor remotely safe distance. Supporting materials on the implementation of the method of tightness control and a control sample are presented by a video report on the website www .. The devices can find wide consumer demand due to ease of use and high adaptability to solving especially important problems in tightness control. Thus, the technical problem is solved in this group of inventions.

References taken into account

1. US Patent 5,979,239 "Ultrasonic imaging system"; 73 / 24.01; 73/597; 1999.

2. US Patent 5,710,377 "Ultrasonic leak detection system"; 73/584; 73 / 40.5A; 73/585; October 17, 1995.

3. RU, 1516815, copyright certificate, cl. G01M 3/24, 1987.

4. RU, 1516815, copyright certificate, cl. G01M 3/24, 1987.

5. RU (11), 94040121 A1, application for invention, cl. G01M 3/00, 1994.

6. RU, 1188556, copyright certificate, cl. G01M 3/24, 1984.

7. RU, 838483, copyright certificate, cl. G01M 3/24, 1979.

8. RU, 456165, copyright certificate, cl. G01M 3/24, 1972.

9. US Patent 6,247,353 "Digital ultrasonic monitoring system and method"; 73 / 40.5A; 73/632; December 10, 1999.

10. RU, 2127877, copyright certificate, cl. G01M 3/24, 1992. (Prototype)

11. RU, 711408, copyright certificate, cl. G01M 3/24, 1980.

12. RU, 2402003 C1, copyright certificate, cl. G01M 3/02, 2009. (Prototype)

13. RU, 1312426, copyright certificate, cl. G01M 3/24, 1986.

14. RU, 1295250, copyright certificate, cl. G01M 3/24, 1985.

15. RU, 712716, copyright certificate, cl. G01M 3/24, 1978.

16. Utkin VE, Development of ways to improve the technology for checking the tightness of hull structures and determining the applicability of the non-contact acoustic test method. The dissertation for the degree of candidate of technical sciences. St. Petersburg. 1999 (OD RSL, 141406, Khimki, Moscow oblast, ul.Bibliotechnaya, 15)

17. Pokora IN, Study of the acoustic spectra of the sound of a jet arising from the outflow of gases from a small-diameter hole. The dissertation for the degree of candidate of technical sciences. Odessa. 1970 (OD RSL, 141406, Khimki, Moscow region, ul.Bibliotechnaya, 15)

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21. PB 03-576-03 Rules for the design and safe operation of vessels operating under pressure. Moscow, 2003, PIO OBT, 187 p.

22. RD 26-12-29-88 Rules for conducting pneumatic testing of products for strength and tightness. Moscow, 2001, IPK Standards Publishing House, 25 pp.

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24. GOST 8.586.1-2005 GSI. Measurement of the flow rate and amount of liquids and gases using standard constricting devices. Part 1. The principle of the measurement method and general requirements. Moscow, 2007, Standardinform, 41 pp.

25. RD 50-411-83 Guidelines for the flow of liquids and gases measurement technique using special narrowing devices. Moscow, 1984, IPK Standards Publishing House, 52 pp.

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27. GOST R IEC 61094-3-2001. Microphones are measuring. Moscow, 2010, Standartinform, 16 pp.

Claims (10)

1. The amplifier and shaper of the acoustic field of the through defect — air ultrasound during the expiration of the control gas jet, while ensuring the conversion of the shape of the front of the acoustic field to a shape close to spherical, made in the form of a mesh structure. 2. The amplifier and driver of the acoustic field of the through defect according to claim 1, which is used expanded metal mesh. 3. The amplifier and driver of the acoustic field of the through defect according to claim 1, which is used as a net or twill weave. 4. The amplifier and driver of the acoustic field of the through defect according to claim 1, which is a grid of metal, polymeric materials, or fabric with a pile. 5. A control leak to check the threshold sensitivity of the leak detection equipment and the non-contact acoustic gas method at a distance, ensuring the use of an amplifier and acoustic field driver of a through defect according to claim 1, which is a device containing a housing with a gas inlet, tightly connected to a removable insert with a critical calibrator a micro nozzle, which is a gas outlet by means of a clamping nut, in which fastenings of fixing strips are provided, which provide fixation of the mesh to For instructions contact surface insertion control leakage. 6. The control leak according to claim 5, characterized in that the mass flow rate characteristic of the critical micro-nozzle being verified is a measure for calibrating leak detection equipment and the non-contact acoustic gas method at a distance based on the cross-sectional area of the calibrated critical micro-nozzle, temperature, and pressure of the control medium in the control object during testing and at the inlet of the control leak during the threshold sensitivity test. 7. The control leak according to claim 5, configured to calibrate the leak detection equipment and the acoustic gas method at a distance less than that required by the safety standards for conducting pneumatic tests. 8. The control leak according to claim 5, made with the possibility of observing the unity of parameters when conducting pneumatic tests by connecting to a gas line with a control medium, which ensures the supply of a control medium to the control object. 9. The control leak according to claim 5, in which the clamping nut with a through hole providing gas exit from the calibrated micro nozzle opening, and a replaceable insert with a critical micro nozzle form a measuring capacitance. 10. The control leak according to claim 9, in the measuring capacity of which an indicator scale is made with risks for determining the volume of liquid poured into it.

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