RU2813672C1 - Device for ultrasonic inspection of local sections of rails - Google Patents

Abstract

FIELD: measurement and control; rail vehicles.

SUBSTANCE: use for ultrasonic inspection of local sections of rails. Essence of the invention consists in the fact that device for ultrasonic inspection of local sections of rails comprises a frame enclosing an ultrasonic wheel search system with an elastic shell, filled with an immersion liquid and equipped with a set of electroacoustic transducers, angles of entry, the number of which is selected based on the required resolution and completeness of sounding of the controlled section, a support roller and a displacement sensor placed on opposite ends of the frame, wherein design of device is made with possibility of scanning various surfaces of rail, frame is equipped with retractable and folding support elements and is equipped with a constant handle, which enables to move the wheel search system along the selected rail surface.

EFFECT: improving reliability of ultrasonic inspection of local sections of rails with simultaneous increase of inspection efficiency and reduction of device weight.

3 cl, 6 dwg

Description

The invention relates to an acoustic type of non-destructive testing and can be used in ultrasonic testing of local sections of rails according to indications of high-speed and removable flaw detection equipment.

Despite the development of automated inspection of rails using flaw detector cars, diagnostic complexes and combined vehicles (flaw detection means - DS) with high productivity, ultrasonic (US) local inspection devices are still in demand on railways. Defective rail sections discovered during continuous high-speed scanning require clarification using portable ultrasonic flaw detectors to identify the degree of danger of the defect and take appropriate measures [1]. According to the current technology, single-channel ultrasonic flaw detectors with a hand-held electroacoustic transducer (EAT) connected to it are used for this purpose. By moving the EAP along the surfaces of the rail, the defective section is scanned from different sides, the presence of a defect is determined, its parameters and coordinates along the rail cross-section are specified. In this case, sequential scanning of the cross-section with hand-held EAPs with different angles of input of ultrasonic vibrations is required [1].

Due to the rough (untreated) surface, not all rail surfaces (for example, the surfaces of the soleplate) are suitable for scanning with a hand-held transducer. The secondary control process can take considerable time (up to 30 minutes), which is not always possible or acceptable. For example, on the railway on the Moscow - St. Petersburg line, the time interval between trains is sometimes only 15 minutes, which means that the possible time for clarification control should not exceed 5 minutes.

To speed up the process of ultrasonic testing of local sections of rails, various devices have been proposed. For example, known devices for ultrasonic testing of rails [2 - 7] contain a sliding probe unit (SL) along the rolling surface and lateral surfaces of the rail head of a group (ruler) of EAP, which inputs and receives ultrasonic vibrations into the controlled section at different angles. The disadvantage of the known devices is a low reliability of control and a limited scope of application due to the fact that the devices are intended only to search (clarify) defects in the rail head. Using traditional SL sliding systems, it is difficult to ensure acoustic contact on uneven and damaged surfaces, which is typical for zones (sections rails) formation of internal rail defects.

The disadvantages of sliding systems are partially compensated for in the second type of system for input and reception of ultrasonic vibrations, which is designated as a “wheel-type system”, “rolling system”, “Roller search units” (Roller search unit - RSU) or “wheeled search systems” (WIS). [8]. In CIS, emitters-receivers of ultrasonic vibrations are positioned inside a wheel-shaped container filled with contact fluid and rolling along rails, and the wheel has an elastic shell that can adapt to unevenness on the surface of the rails [9]. In wheeled systems, friction resistance is replaced by rolling resistance, which ensures the durability of the structure and protection of the main elements of the search units - ultrasonic transducers (mainly EAP based on the piezoelectric effect). Moreover, a more stable contact compared to the SL sliding system can be achieved with a significantly (30%) lower consumption of the contacting liquid supplied to the contact zone of the elastic shell with the rail surface [10, 11].

There are known devices [12 - 14], implemented using one or two CIS and providing input and reception of ultrasonic vibrations through the tread surface of the controlled rail. Known devices have a limited scope and insufficient control reliability (there is no control of the sole feathers, control of the head and neck of the rail from the side surfaces).

Ultrasonic monitoring devices for railways are known. rails over the entire cross section using CIS placed on several surfaces (rolling surface and side surfaces of the head, neck and sole) of the controlled rail [15 - 16]. However, they have a bulky design, are mainly intended for monitoring rails in stationary conditions during their production and welding and cannot be used for operational monitoring of local sections of rails laid on the track.

An ultrasonic device for monitoring local sections of a rail is known [17], containing co-directional inclined EAPs in the form of lines of piezoplates in roller transducers with an elastic shell, installed in the vicinity of the expected defect on the lower faces and on the rolling surface of the rail head and implementing the shadow method of ultrasonic testing. The disadvantage of the known device is the limited scope of application caused by the suitability of the device only for assessing rail head defects. Moreover, the use of several CIS, rigidly interconnected to implement the co-directionality of the EAP, increases the dimensions of the device.

A device for ultrasonic testing of local sections of rails is known [18], containing a CIS with an elastic shell, containing a set of EAPs, the input angles and number of which are selected based on the required resolution and completeness of sounding of the inspected section, the CIS is synchronously moved along the scanned rail surfaces, and the defective part is periodically probed. The section is received by ultrasonic signals arriving through the controlled section of the rail (shadow method of control), and a decision is made about the presence of a defect in the rail head. The disadvantage of the known device is its limited scope of application (only for searching for defects in the rail head), complexity of implementation, low reliability and testing performance.

A hand-held ultrasonic flaw detection device [19] is known for monitoring local sections of rails, consisting of a frame with two support wheels, a CIS with a set of EAP located on the frame between the support wheels, two side plates covering the frame, on the platform between the plates there is a container for contacting liquid, and the upper end parts of the side plates are equipped with handrails (handles) for pushing the single-thread device along the rail thread. The disadvantage of the known device [19], adopted as a prototype, is the limited scope and low reliability of control, caused by the possibility of introducing ultrasonic vibrations when testing local sections of rails only from the rolling surface of the controlled rail.

The problem to be solved by the claimed invention is the creation of a device for ultrasonic testing of local sections of rails with the ability to detect defects throughout the entire section while simultaneously increasing the reliability and performance of testing.

The solution to the problem is ensured by the fact that in a device for ultrasonic testing of local sections of rails, containing a frame covering a wheel search system with an elastic shell, filled with immersion liquid and containing a set of electroacoustic transducers, the input angles and number of which are selected based on the required resolution and completeness of sounding of the monitored sections located at opposite ends of the frame, a support roller and a displacement sensor, the contact surfaces of which are on the same level with the contact surface of the CIS, and the wheel design is made with the ability to scan various surfaces of the controlled rail, the frame is equipped with retractable and folding support elements and a permanent handle that allows you to move CIS on the required rail surfaces. Additionally, a sensor for fixing a marker installed on the surface of the rail is located on the frame of the CIS; the electrical leads of the sensor for fixing the marker, the displacement sensor and the EAP are connected to the electronic unit of the ultrasonic flaw detector.

In a particular case, the CIS frame is equipped with a quick-release rod with a container for the contacting liquid, nozzles are provided on the cylindrical surface of the support roller, and on the end part there is a fitting for connecting a hose connecting the roller to the liquid container.

The authors, except for [17 -19], were unable to find technical solutions aimed at manual control of local sections of rails using CIS. Apparently this is due to the fact that typical ultrasonic wheels for rail inspection have a size of 6 or 8 inches (203 mm!) and, accordingly, a significant weight. Due to their size, they do not allow scanning from the side surfaces of the head and the surfaces of the neck and feather of the rail base. The large mass of the CIS determines the use of more massive accompanying structural elements (frame, support roller, etc.) of the scanner. As a result, a hand-held scanner turns out to be bulky, with limited capabilities and not suitable for the use of operational, clarifying inspection of local sections of rails.

The claimed device proposes to use a CIS of reduced size and made of lightweight materials, which, together with other technical solutions, makes it possible to increase the reliability and performance of monitoring local sections of the rail track.

Significant differences of the proposed device compared to the prototype are:

1. The design of the wheeled search system is made with the ability to scan various surfaces of the controlled rail. Fulfilling this requirement allows, on the one hand, to increase the inspection productivity (there is no time wasted on connecting different scanners for different surfaces), on the other hand, to significantly reduce the weight, dimensions and cost of the wearable set of the operator (flaw detector) of secondary inspection. In the prototype, the CIS design allows scanning only from the rolling surface of the rail.

2. The CIS frame is equipped with retractable and folding support elements. Making the support elements retractable or folding allows, on the one hand, scanning from any surface (for example, from the rolling surface of a rail) while observing the specified trajectory of the CIS, and on the other hand, does not interfere with ultrasonic scanning when moving the CIS to other surfaces (for example, to a sole feather) rail.

3. On the frame of the CIS there is a sensor for fixing the marker installed on the surface of the rail. The authors are not aware of ultrasonic testing devices for local areas that record the presence and coordinates of a marker on the test object simultaneously with echo signals from the defect. In the prototype, issues of rail control from surfaces other than the rolling surface are not considered.

4. The electrical terminals of the marker fixation sensor, displacement sensor and EAP are connected to the electronic unit of the ultrasonic flaw detector. Joint processing in the flaw detector unit of signals from the marker, odometer (displacement sensor) and echo signals from the desired defect allows for correct synchronization of measurement data obtained from different surfaces of the rail and creates the condition for the formation of a detailed image of the internal defect of the rail.

5. The CIS frame is equipped with a quick-release rod with a container for contacting liquid. The presence of a rod expands the scope of application of the proposed device, and the ability to quickly attach/detach it to the CMS frame increases the reliability of the obtained ultrasonic testing results. When scanning a relatively extended area using a CIS with a rod and detecting a local area with a suspected internal defect, it is possible to quickly switch to careful monitoring of the defective section from different surfaces of the rail, and after assessing the defective section, immediately (quickly) switch to continuous scanning.

6. There are nozzles on the cylindrical surface of the support roller, and on the end part of the support roller axis there is a fitting for connecting a hose connecting the roller to the liquid container. This distinctive feature is an original technical solution that allows, with limited dimensions and weight of the device, by performing several functions by one of the device components, to obtain an additional result: applying a contacting liquid over the entire width of the scanned surface, increasing the reliability and reliability of control.

The combination of essential features of the proposed device allows us to obtain a technical result: increasing the reliability of inspection of local sections of rails while simultaneously increasing inspection performance and reducing the weight of the scanner (portable flaw detector set).

The claimed device is illustrated by the following graphic materials:

Fig. 1. Design of a scanner based on CIS (side view), where:

1 - wheel with an elastic shell (wheel search system);

2 - rail surface;

3 - frame;

4 - CIS axis;

5 - support roller with nozzles and a fitting for supplying contacting liquid;

6 - displacement sensor;

7 - constant (arched) handle;

8 - quick-release rod;

9 - retractable lateral movement limiter;

10 - retractable stopper; 19 - marker fixation sensor.

Fig. 2. Design of a scanner based on CIS (top view), where:

11 - monoblock with EAP (mainly piezoelectric plates);

12 - restriction roller;

13 - folding stop (in non-working position).

Fig. 3. Position of the CIS on the rail rolling surface, where:

10 - retractable stopper;

14 - rail head.

Fig. 4. Position of the CIS on the side surface of the rail head.

Fig. 5. The position of the CIS on the forefoot, where:

15 - rail neck;

16 - sole feather.

Fig.6. A device for monitoring an extended section of track, where:

17 - removable rod clamp;

18 - container for contacting liquid.

The basis of the scanner is an ultrasonic wheel (USW) 1 (Fig. 1), mounted on the scanning surface 2 of the rail and covered by a frame 3. The axis 4 of the wheel is fixed to the protrusion of the frame 3. At the ends of the frame 3 there is a support roller 5 and a displacement sensor (odometer) 6 The specified units 1, 5 and 6 of the device are designed to roll along the scanned surface 2 of the controlled rail, and their contact surfaces are at the same level (on the scanned surface of the rail).

The ability to scan various surfaces of the controlled rail (heads from 3 surfaces is determined by the main geometric parameters of the CIS: diameter D and width K. On the one hand, the width of the CIS should provide the ability to place inside a sufficient number of EAPs, allowing the entire controlled section to be covered in the process of a single scan. C On the other hand, the need to scan the side surfaces of the rail head and neck, the upper surfaces of the sole stays, limits the maximum possible dimensions of a wheel with an elastic shell.In the general case, it is advisable to focus on the width F of the rail head (K ≈ 0.8F).

Wheel diameter D should be selected based on the following conditions:

- when searching for defects in the sole feathers, the overall dimensions of the wheel should not touch the lower edge of the rail head;

- EAPs placed inside the wheel cause a fairly long travel time for ultrasonic vibrations to the contact surface of the rail. Therefore, the expected time of appearance of echo signals from internal defects is shifted relative to the probing pulse by the amount of propagation of ultrasonic vibrations in the immersion liquid and in the thickness of the elastic (polyurethane) shell of the CIS. Critical here is the sounding of the rail over the entire height H by a direct EAP with an input angle of ultrasonic vibrations of 0° (Fig. 1). In order to eliminate the ambiguity of isolating the bottom signal (from the base of the rail), the diameter of the wheel D is selected from the conditions obtained from geometric considerations and taking into account the travel time of ultrasonic vibrations inside the wheel and in the rail:

Where - height of the head and bottom of the rail;

- rail height (180 mm for rail type P65);

- the speed of propagation of ultrasonic vibrations in the immersion liquid in the wheel (about 1.5 mm/μs, depending on the composition of the liquid);

- speed of longitudinal ultrasonic wave in the metal of the rail (5.9 mm/μs).

For experimental studies of the proposed device using the obtained expression, for the dimensions of the P65 type rail, the CIS parameters were selected: diameter D=110 mm, width K=60 mm (Figs. 1 and 2). In the general case, the device can be implemented using CIS with other dimensions that satisfy expression (1).

Despite the fact that in the process of ultrasonic testing of a local section of the rail, the device is controlled using a constant handle 7 manually, to maintain a straight trajectory of the CIS movement along the rail, corresponding auxiliary limiters (item 9 in Fig. 1) and stops 12 and 13 are provided. When introducing ultrasonic vibrations from the rolling surface of the rail, a retractable transverse movement limiter 9 with a lock 10 is used (Fig. 1 - 3). When scanning from the side surfaces of the head 14, a folding stop 13 is used (Fig. 4); when monitoring the feathers of the rail sole 16, a limit roller 12 is used (Figs. 2 and 5). When scanning from the surface of the 15th rail journal, you can do without auxiliary limiters.

For continuous scanning of the rail from the rolling surface over a long section of track (20 - 100 m), the possibility of temporarily attaching a quick-release rod 8 is provided. Rod 8 is also required when inspecting elements of turnouts and extended sections of the rail track that are unsuitable for inspection for traditional sliding systems. When manually checking the local section of the rail, the rod is disconnected from the scanner.

A certain problem when monitoring extended areas with a scanner for local control is the supply of contacting liquid to the scanned surfaces. The original support roller 5 with a fitting and nozzle holes placed evenly along the diameter also serves to supply contacting liquid from a container 18 attached to the rod 8 (Fig. 6).

Inside the wheel 1 with an elastic shell filled with immersion liquid, there is a monoblock 11 with a set of piezoelectric plates (PEP) with different angles of input of ultrasonic vibrations into the controlled rail through the wheel/rail contact patch (Fig. 2). As an example, a set of 9 piezoelectric plates is shown: 70° (3×2 EAP), 42° (3×2 EAP) and 0°. In general, depending on the problems being solved, the number of piezoelectric plates may be different (one or more) with the required angles of input of ultrasonic vibrations into the controlled object.

When monitoring the head or feather of the sole, three piezoplates with an angle of 70° are involved in the work, moving and (or) moving away (70 N or 70 From).

The use of 70° piezoplates across almost the entire width of the head (Fig. 3) and, if necessary, additional scanning from the side surfaces of the head (Fig. 4), allows us to detect almost all possible defects in the rail head.

When monitoring the neck and sole zones of the rail from the rolling surface (in the projection of the neck), three piezoelectric plates with angles of 0°, 42°H and 42°F are also connected.

The use of plates with an angle of 70° (or 42°) for scanning in the intersleeper spaces of the sole feathers (Fig. 5) will make it possible to detect transverse cracks in the sole, including under intermediate rail fastenings. Currently, this technology is new and is aimed at solving one of the main problems of railways regarding fractures due to defects in the sole (up to 34% of fractures per year [20]).

The operation of the device is obvious from the provisions of the CIS in Figs. 3-5. As a rule, the initial coordinate of a possible defect in the rail is obtained after continuous monitoring of the rail track using a high-speed DS. At the same time, the estimated zone of occurrence of the defect (in the head, neck or foot) of the rail is also indicated. The operator of the secondary (clarification) control goes to this path coordinate with a portable ultrasonic flaw detector (not shown in the figure) equipped with the inventive device (wheel scanner). It is preferable to use a multichannel ultrasonic flaw detector.

When using a single-channel ultrasonic flaw detector, switching of the corresponding EAP, depending on the scanned areas of the defective section, is performed using a hardware-software method (multiplexer) of the external flaw detector. The low speed of movement during manual scanning (no more than 200 mm/s) and the short time of propagation of ultrasonic vibrations to the desired defect and back (about 300 μs), even taking into account the additional time of propagation of ultrasonic waves in the immersion liquid of the CIS, allows such switchings to be performed without compromising discreteness sounding along the length of the rail and unnoticed by the operator.

When the DS indicates the possible presence of a defect in the rail head 14, in the vicinity of the supposed defect, a CIS 1 with built-in EAP 11 is installed on the rolling surface of the rail, introducing ultrasonic vibrations into the rail at a typical input angle of 70° (Fig. 3). In this case, the dimensions of the CIS make it possible to place three to four pairs of standard piezoelectric plates along the width of the CIS, oriented along the length of the rails in opposite directions (Fig. 2), making it possible to practically cover most of the section of the rail head.

As the CIS 1 rolls along the rolling surface, the defective section of the rail head is sounded on one side and the other (along the length of the rail), and if there is a defect, at least one or more of the above-mentioned EAPs record echo signals from it. The retractable lateral movement limiter 9, which, when scanning from other surfaces of the rail, is moved to the non-working position using the latch 10 (Fig. 1 - 3), ensures that the linear trajectory of the CIS movement along the rolling surface 2 of the rail is maintained.

When observing signals of insignificant amplitude from the desired defect, to further clarify the parameters of the defect, the CIS is installed on one of the side surfaces of the rail head (Fig. 4). The folding stop 13 is installed on the rolling surface 2 of the rail and scanning is repeated (the CIS is rolled) along the rail in the vicinity of the defective section. Such scanning is especially desirable if the rolling surface of the rail is damaged by microcracks, peeling and spalling of the metal (defects of the first group according to [21]), which make it difficult to introduce ultrasonic vibrations from the rolling surface.

In the most difficult situations caused by an atypical crack orientation or significant wear on the side surface of the rail head, a similar scan is performed on the other side surface of the rail.

Thus, when using the inventive device, the section of the rail head in the vicinity of the alleged defect is sounded in the most thorough manner from three surfaces of the head and from both sides (relative to the longitudinal axis of the rail) of the defective section. If there is a defect, all possible echo signals will be recorded, the joint analysis of which allows an unambiguous and reliable assessment of the detected defect.

With an average speed of movement (rolling of the CIS) of about 100 mm/s and a length of the vicinity of the defective section of 500 mm, the total scanning time over three surfaces does not exceed 15 s. As a result, the use of the proposed device makes it possible to increase the reliability of detection and evaluation of defect parameters and inspection performance.

Defects in the neck and in the central part of the sole (in the projection of the neck) can be detected using EAP in the wheel, which introduces ultrasonic vibrations from the rolling surface at an angle α = 0° (normal input of longitudinal ultrasonic vibrations) and multidirectional inclined EAP, for example, under angle α = ±42°. If it is necessary to clarify the parameters of a defect in the rail web, the CIS can be installed on the rail web. The sole feathers (Fig. 5), which are usually inaccessible to ultrasonic testing with known devices, can be scanned in a similar way. When sounding sections of the rail foot area during scanning from the surface of the rails, EAPs with ultrasonic vibration input angles of 70° can be used, used when inspecting the rail head.

The indicated angles of ultrasonic vibrations and their combinations are given to demonstrate the capabilities of the device and its effectiveness in detecting and assessing the parameters of defects over almost the entire cross section of the rail. In the general case, it is possible to use other EAPs at other angles of input and rotation of ultrasonic vibrations relative to the scanning direction (Fig. 5).

The sensor 19 for fixing the marker, installed by the operator of the clarifying control at the specified DS coordinate of the path, is placed on the frame 3 of the device (Fig. 1) and, depending on the type of marker used (not shown in the Fig.), may have an appropriate design and principle of operation. Any known structures can be used as a marker, for example, in the form of a pre-magnetized composite material with high plastic functions [22, 23]. In this case, a magnetically sensitive sensor, for example, a Hall sensor [24], connected to the electronic unit of the flaw detector, is used as the marker fixation sensor 11.

The electrical terminals of the marker fixation sensor, displacement sensor and EAP are connected to the electronic unit of the ultrasonic flaw detector (not shown in the figure). Providing the device with the possibility of joint processing in the flaw detector unit of signals from the marker, odometer (displacement sensor 6 in Fig. 1) and echo signals from the desired defect allows correct synchronization of measurement data obtained from different surfaces of the rail and creates the condition for the formation of a detailed image of the internal defect in rail, and in general, increasing the reliability of control.

In order to expand the scope of application of the device, it is possible to attach a rod 8 to the frame 3 of the scanner using a clamp 17 (Fig. 6). This design allows you to quickly monitor not only individual defective sections of the rail, but also use the inventive device to monitor longer sections of the rail track (Fig. 6): sections with unsuitable (for sliding systems) rail rolling surfaces; elements of turnouts, etc., usually not exceeding the length of 35 - 100 m of track. The quick-detachable design of the rod allows you to quickly move from continuous scanning of anomalous sections of the rail track to monitoring a local section from different surfaces of the rail in the above manner. This option also improves overall rail inspection performance.

Experimental testing of the device was carried out using a multi-channel ultrasonic flaw detector AGZIKON-20, with the ability to display control signals in the form of a type B sweep, and a CIS with a diameter of 110 mm produced by Radioavionics JSC when testing rails with models and real defects.

One skilled in the art will understand that the present invention is not limited to the exemplary embodiments described above, and that other numerical values of device elements and implementation parameters are possible within the scope of the present invention, as defined by the appended formulas.

Thus, the proposed device can be implemented, improves the reliability and reliability of detection of internal rail defects, increases inspection performance and has a low mass, which is important for manual clarifying inspection of local sections of the rail track according to high-speed DS readings.

Information sources

1. Regulations on the system of non-destructive testing of rails and the operation of rail flaw detection equipment in the track facilities of the railways of JSC Russian Railways. No. 1471/r dated July 26, 2017 (P.8 p. 76-90).

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Claims (3)

1. A device for ultrasonic testing of local sections of rails, containing a frame covering an ultrasonic wheeled search system with an elastic shell, filled with immersion liquid and equipped with a set of electroacoustic transducers, input angles, the number of which is selected based on the required resolution and completeness of sounding of the inspected section; a support roller and a displacement sensor located at opposite ends of the frame, characterized in that the design of the device is made with the ability to scan various surfaces of the rail, the frame is equipped with retractable and folding support elements and is equipped with a permanent handle that allows you to move the wheeled search system along the selected rail surface. 2. A device for ultrasonic testing of local sections of rails according to claim 1, characterized in that a sensor for fixing a marker mounted on the surface of the rail is placed on the frame of the wheeled search system; The electrical terminals of the marker fixation sensor, displacement sensor and electroacoustic transducers are connected to the electronic unit of the external ultrasonic flaw detector. 3. A device for ultrasonic testing of local sections of rails according to claim 1, characterized in that the frame of the wheel search system is equipped with a quick-release rod with a container for contacting liquid, nozzles are provided on the cylindrical surface of the support roller, and a fitting for connecting a hose is provided on the end part of the roller axis connecting the roller to the liquid container.