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– this is a complex procedure during which the technical condition of the objects being assessed is determined. These can be not only industrial equipment and devices, but also technical documentation.
Assessment activities make it possible to determine the level of equipment performance, prevent possible accidents, and also reduce the likelihood of downtime due to breakdowns and malfunctions.
In accordance with the current standard GOST 20911-89 " Technical diagnostics. Terms and definitions" when conducting technical diagnostics, the expert should not limit himself to the assessment current state object. Its tasks include determining the reasons for the failure of the device, as well as making a forecast regarding the further operation of the object and assessing its residual life.
The customer must understand that equipment assessment can be carried out in two directions. GOST contains two key concepts: “Technical diagnostics” and “Control technical condition" This allows the customer to formulate a current task, and then the test will help to quickly detect a malfunction or assess the condition of the equipment. This approach saves the reserve’s time and helps optimize costs for expert services.
Technical diagnostics of technical devices is not mandatory, it is carried out at the initiative of the customer who has expressed a desire to obtain an objective assessment of the technical and operational characteristics of their equipment. The customer should not confuse technical diagnostics and examination. In the second case, the assessment of the condition of the object is carried out in accordance with the law and does not imply the possibility of refusal by the owner of the enterprise. Being an effective instrument of state control, technical examination is carried out only in cases where the work of the enterprise has not yet begun or has been suspended by court order.
Objects of technical condition assessment
Technical diagnostics are carried out in relation to:
- Gas and oil pipelines;
- Hot water and steam pipelines;
- Systems operating under pressure or at elevated temperatures;
- Objects subject to boiler inspection;
- Technological pipelines;
- Equipment operating in hazardous industries;
- Reservoirs;
- Lifting structures, etc.
Types of technical diagnostics of technical devices
Depending on the characteristics of the object being assessed, one of six types of control can be applied. Thus, when assessing objects of the same type, specialized control will be required; for different types, a universal method is used. Automated and automatic, external and built-in controls may also be involved.
When carrying out non-destructive testing, many various techniques, which, as a rule, are effective in combination.
Non-destructive testing involves, first of all, assessment through measuring and visual methods. Other methods may also be required, for example:
- Ultrasonic flaw detection;
- Electrical and electromagnetic flaw detection;
- Eddy current flaw detection;
- X-ray flaw detection;
- Magnetic flaw detection;
- Acoustic emission flaw detection;
- Thermal flaw detection;
- Vibration flaw detection;
- Control by penetrants.
If there is a need to conduct destructive tests, other approaches are used, during which experts identify the mechanical properties of the material under study and its features chemical composition, resistance to natural factors, characteristics of the macro- and microstructure of metals, etc.
How is technical diagnostics carried out?
Carrying out activities to assess the research object depends on technical characteristics equipment. Nevertheless, general order diagnostic work can be determined. It is like this:
- Study of technical documentation for the object being assessed;
- For equipment that has already been in use - carrying out preparatory work, including disconnecting the device from communications, cleaning, removing heat-insulating materials, etc.;
- Conducting functional diagnostics;
- Defining a diagnostic program for a specific device or group of devices;
- Visual inspection of equipment;
- His detailed research;
- Preparing of report.
Technical diagnostics are carried out in accordance with regulatory documentation, which sets out at the legislative level methods for assessing the device and measuring its main parameters.
Results of the study
After analyzing and processing the received data, the expert enters the results of technical diagnostics into the equipment data sheet. If a specialist has determined that further operation of the device may endanger the life and health of the person working with it, as well as pose a danger to environment and property of third parties, the customer of the examination is informed about this. Also notified territorial body executive power, whose competence includes supervision in the field of industrial safety– this is the responsibility of the expert.
The customer can contact the organization that carried out the technical diagnostics with a request to issue an expert opinion. This document is issued on the basis of a report on the tests and research carried out. The report contains links to regulatory documentation, industry rules and orders of the enterprise that ordered the assessment. The report also contains information on the compliance of the technical and operational parameters of the facility job descriptions, methodological instructions and industrial safety requirements.
IN expert opinion is given:
- Reasonable assessment of device performance;
- Determining the level of industrial safety of the facility;
- Service life assessment
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Technical diagnostics- this is the process of analysis, conclusions and conclusions about the technical condition of equipment, in which the degree of serviceability of the technical device is determined, due to comparative analysis received data with the parameters established in the technical documentation. According to GOST 20911-89, technical diagnostics is the determination of the technical condition of objects.
Technical diagnostics- a field of knowledge covering the theory, methods and means of determining the technical condition of objects.
The objectives of technical diagnostics are:
- technical condition monitoring;
- searching for the location and determining the causes of failure (malfunction, defect);
- forecasting technical condition.
Technical condition monitoring is carried out to check the compliance of the parameter values of the diagnostic object with the requirements of technical documentation, and to determine on this basis one of the types of technical condition at a given time. The types of technical condition of the diagnostic object are: serviceable, operational, faulty, inoperative.
Working condition: the state of the diagnostic object, in which it meets all the requirements of regulatory, technical and (or) design (project) documentation.
Working condition: the state of the diagnostic object, in which the values of all parameters characterizing the ability to perform specified functions comply with the requirements of regulatory and technical and (or) design (project) documentation.
Forecasting the technical condition is the determination of the technical condition of the diagnostic object with a given probability for the upcoming time interval. The purpose of predicting the technical condition is to determine, with a given probability, the time interval (resource) during which the operational (serviceable) state of the diagnostic object will remain.
When is technical diagnostics carried out?
Technical diagnostics using non-destructive and destructive testing methods is carried out:
- during operation within the service life, in cases established by the operating manual,
- when conducting a technical examination to clarify the nature and size of identified defects,
- upon expiration of the design service life of equipment under pressure or after exhaustion of the design service life of safe operation within the framework of an industrial safety examination in order to determine the possibility, parameters and conditions of further operation of this equipment.
- at the end of the service life specified by the manufacturer for lifting structures and equipment under pressure that are not subject to registration in Rostechnadzor, in order to determine the residual service life, parameters and conditions for further safe operation.
How is technical diagnostics carried out?
Technical diagnostics of technical devices includes the following activities:
- visual and measuring control;
- operational (functional) diagnostics to obtain information about the condition, actual operating parameters, actual loading of a technical device under real operating conditions;
- determination of current damaging factors, damage mechanisms and susceptibility of the technical device material to damage mechanisms;
- assessment of the quality of connections of technical device elements (if available);
- selection of non-destructive or destructive testing methods that most effectively identify defects resulting from the influence of established damage mechanisms (if any);
- non-destructive testing or destructive testing of metal and welded joints of a technical device (if available);
- assessment of identified defects based on the results of visual and measuring control, non-destructive or destructive testing methods;
- research of technical device materials;
- calculation and analytical procedures for assessing and predicting the technical condition of a technical device, including analysis of operating modes and study of the stress-strain state;
- assessment of residual resource (service life);
Based on the results of technical diagnostic work, a technical report is drawn up with non-destructive testing protocols attached.
Who carries out technical diagnostics?
Work on technical diagnostics using non-destructive and/or destructive testing methods is carried out by laboratories certified in accordance with the Certification Rules and basic requirements for non-destructive testing laboratories (PB 03-44-02), approved by the Decree of the Federal Mining and Industrial Supervision of Russia dated June 2, 2000 city No. 29.
Khimnefteapparatura LLC has its own certified laboratory for non-destructive testing and technical diagnostics Certificate No. 91A070223, equipped necessary equipment, instruments and measuring instruments certified in in the prescribed manner staffed with level II non-destructive testing specialists certified in accordance with PB 03-440-02 with the right to perform types of testing:
- visual-measuring,
- ultrasonic flaw detection,
- ultrasonic thickness gauging,
- control by penetrating substances (capillary),
- magnetic (magnetic particle) control,
- acoustic emission control.
All specialists are certified by the Rostechnadzor commission on industrial safety in their respective fields. The personnel have been trained and allowed to work at heights from lifts and towers. The division includes geodetic control specialists who have undergone specialized training.
Khimnefteapparatura LLC carries out technical diagnostics of:
- boilers;
- pipelines;
1.1. These "Recommendations for the technical diagnostics of lifting structures" (hereinafter referred to as the "Recommendations") have been developed in accordance with and in development technical regulations"On the safety of machinery and equipment", approved by Government Decree Russian Federation dated September 15, 2009, No. 753, and also in accordance with Federal law dated July 21, 1997 No. 116-FZ “On the industrial safety of hazardous production facilities and are advisory in nature.
1.2. The recommendations are intended for experts and certified specialists of expert organizations performing work on technical diagnostics of substations, owners of substations (regardless of their form of ownership), as well as employees of the federal executive body specially authorized in the field of industrial safety of substations.
2. Scope of application
2.1. These Recommendations are intended for use in technical diagnostics of substations: load-lifting cranes of all types, electric hoists, monorail trolleys, loader cranes, pipe-laying cranes, elevators, towers, load-handling devices as part of cranes, individual load-handling devices, as well as crane rail tracks in order to determine their technical condition and the possibility of further operation.
The recommendations regulate the procedure for carrying out technical diagnostics, determine the fundamental composition of the work, which makes it possible to objectively assess the technical condition, the actual load-bearing capacity of metal structures, substation mechanisms and, if necessary, make informed technical decisions on repair and restoration measures or methods of reinforcement.
types, frequency and scope of technical diagnostics of substations depending on the conditions and specifics of their operation;
methodological foundations and sequence of technical diagnostics;
a nomenclature of diagnostic parameters and qualitative features that characterize the technical condition of the lifting structure and ensure the search for its possible defects and damage;
nominal, permissible, limiting values of structural diagnostic parameters and the dependence of parameter values on the operating time of the substation;
requirements for measurement error of parameters;
nomenclature of diagnostic tools, operating modes of the substation and its components when carrying out technical diagnostics;
labor protection requirements for technical diagnostics.
3.1. Scroll regulatory documents, to which references are given in these Recommendations, are given in section 2. FNP PS.
When excluding from the existing normative documents referred to in these Recommendations, one should be guided by the norms introduced to replace the excluded ones.
4. Terms and definitions
Operating state limited(limited operational state) - condition metal structures PS, in which the values of the parameters characterizing its ability to perform specified functions are not implemented in full (for example, at a limited reach, or with limited load capacity, etc.), but while ensuring all mandatory safety requirements (strength, rigidity, stability, etc.).
Emergency condition- state metal structures PS, in which its further operation is prohibited until repair and/or strengthening measures are completed.
Limit state criterion- a sign or set of signs of a limiting state of a substation, established by regulatory and (or) design (project) documentation, taking into account the assigned permissible risk.
Technical diagnostics– a set of works performed at the substation in order to obtain an objective assessment of its technical condition, as well as issue a conclusion defining the terms and conditions (acceptable risk) for the further safe operation of the lifting structure.
Primary technical diagnostics– technical diagnostics carried out for the first time at the substation, but no later than the expiration of the designated service life of the substation.
Repeated technical diagnostics- technical diagnostics carried out after the expiration of the period established based on the results of the initial or previous repeated technical diagnostics of the PS.
Extraordinary technical diagnostics- technical diagnostics, carried out in the event of significant defects or damage (or signs of the appearance of these damages) that pose a threat to further operation, carried out in accordance with the requirements set out in newsletters manufacturers or a federal executive body specially authorized in the field of industrial safety, or at the request of the owner of the lifting structure.
Action form for completing technical diagnostics– a document containing a list of work (repairs, reinforcements, etc.) performed on the substation in order to bring it into working condition and ensure that static and dynamic tests are carried out on it upon completion of technical diagnostics.
5. General provisions
5.1. Specialized organizations equipped with the necessary equipment and tools and employing qualified specialists are allowed to carry out work on technical diagnostics of substations. Qualification specialized organization and specialists for the right to carry out technical diagnostics must be confirmed by documents established in Russia for the right to carry out this activity.
5.2. When performing technical diagnostics, one should take into account the specifics of the materials from which the metal structures of the substation are made.
According to this assessment, metal structures of substations are divided into: those in serviceable condition, limited serviceability and emergency condition.
When in working condition, the operation of metal structures under actual loads and impacts is possible without restrictions. At the same time, for structures that are in working condition, a requirement may be established periodic examinations during operation.
When metal structures are in a limited serviceable state, it is necessary to monitor their condition, implement protective measures, and monitor operating process parameters (for example, limiting loads, protecting structures from corrosion, restoring or strengthening structures). If structures with limited functionality remain unreinforced, then mandatory repeated diagnostics are required, the timing of which is established on the basis of the diagnostics performed.
If metal structures are in an emergency condition, their operation should be prohibited.
5.4. When technically diagnosing substations located in seismically hazardous regions (or seismically hazardous objects), a predictive assessment of the safe state of metal structures should be carried out taking into account the factors of seismic influences:
calculated seismicity of the construction site according to OSR-97 maps;
repeatability of seismic impact;
spectral composition of seismic impact;
categories of soils according to seismic properties.
6. Organizational and technical measures carried out before technical diagnostics
6.1. Work on technical diagnostics of the substation is carried out at the request of the customer, which is registered with an expert organization in the prescribed manner.
6.2. Based on the application, the expert organization conducts a preliminary stage of negotiations with the customer, agreeing necessary list organizational and technical issues:
types of lifting structures and their quantity;
technical characteristics and operating conditions of the substation;
a list of information necessary to carry out technical diagnostics in accordance with the current normative and technical documentation;
requirements mandatory for technical diagnostics;
timing of technical diagnostic work and transfer of the conclusion to the owner of the lifting structure;
other organizational and technical issues.
passport, operating manual 22 and other operational and design documents (the latter, if necessary);
PS, test loads, as well as allocate an experienced crane operator (driver, operator) for the period of technical diagnostics;
equipment and tools for technical diagnostics of metal structures and mechanisms at height (if necessary);
passport of the crane runway, certificate of commissioning of the crane runway and the previous act of plan-altitude survey of the tracks (for substations moving along ground or above-ground crane tracks) in accordance with the requirements of regulatory documents;
protocols for checking insulation resistance and grounding;
documents of repairs (modernizations, reconstructions), if any;
a certificate about the nature of the work performed by the PS;
summary printout from the parameter recorder (for substations equipped with the specified device);
a maintenance log with records of maintenance and routine repairs;
acts and materials of previously conducted inspections and technical diagnostics of this substation.
7. Main stages of work during technical diagnostics
7.1. Technical diagnostics of the substation is generally carried out in accordance with the work program outlined below. It is specified taking into account the type, design and operating conditions of a particular substation.
The technical diagnostic program provides for 3 stages of work:
preparatory;
worker;
final.
selection of regulatory, technical and reference documentation required for technical diagnostics of this type of substation;
familiarization with certificates, operational, repair, design and other documentation for this PS;
conducting passport extracts;
preparation of maps for inspection of the substation (if necessary);
obtaining a certificate about the nature of the PS operation and a printout from the parameter recorder;
checking the conditions and organization of work to prepare the site for technical diagnostics and testing of the substation;
checking technical means and instruments for technical diagnostics of PS;
Conducting safety briefings to members of the commission;
issuance of an order on the composition of the commission and on upcoming volume works
technical diagnostics of the condition of metal structures;
technical diagnostics of mechanisms (mechanical parts of mechanisms);
technical diagnostics of the rope-block system;
technical diagnostics of hydraulic and pneumatic equipment;
technical diagnostics of electrical equipment;
technical diagnostics of instruments and safety devices;
technical diagnostics of the condition of the crane and trolley tracks, as well as track equipment;
Carrying out a horizontal survey of the position of crane tracks (if necessary);
taking control samples from elements of substation metal structures to determine the chemical composition and mechanical properties metal (if necessary);
carrying out instrument testing of metal structures and welded joints using non-destructive testing methods;
carrying out tests (static, dynamic, special).
7.4. The final stage includes:
analysis of technical diagnostic results;
drawing up a form of measures to complete technical diagnostics
registration of non-destructive testing reports, familiarization with the results of testing insulation resistance and grounding; chemical analysis etc., registration of test reports for PS.
calculation of the achieved classification group (mode) PS 23;
developing a decision on the possibility and feasibility of extending the service life of the substation;
recommendations for ensuring safe operation of the substation;
checking the implementation of measures to complete technical diagnostics;
development of the Safety Case document;
drawing up a technical diagnostic report;
transfer of the conclusion to the owner.
8. Scope and content of the main types of work during technical diagnostics
8.1. Familiarization with the documentation.
8.1.1. The owner of a substation subject to technical diagnostics, before starting work, issues an order to the enterprise to transfer this substation or a group of substances for technical diagnostics (initial, repeated or extraordinary), to appoint persons responsible for safety precautions at the facility, for preparing the conditions necessary for carrying out works during technical diagnostics of PS.
8.1.2. In the process of performing technical diagnostic work, the commission must familiarize itself with the available:
certificates for ropes, hooks, metal, fasteners, etc.;
passports for PS and components for which a separate passport is provided (for example, for removable load-handling devices, parameter recorders, brakes, etc.);
instructions for maintenance and operation of the lifting structure;
logs: shift logs, watch logs, records of personnel knowledge testing, safety briefings, qualification data of service personnel; inspection, maintenance and repair of substations and crane tracks;
repair documentation (included);
drawings and calculations performed during the reconstruction or modernization of the substation;
materials of the last full technical examination;
previous conclusions on this PS;
a certificate about the nature of the work of PS 24;
documents on crane tracks (including a crane track passport), track acceptance certificates, results of elevation surveys, etc.);
acts of checking insulation and grounding resistance;
acts of verification of safety devices and measuring instruments;
instructions of the federal executive body specially authorized in the field of industrial safety of the substation and the technical supervision service of the organization that owns the substation.
availability and completeness of documentation;
compliance of existing equipment and its technical data with passport and certification documents;
compliance with the instructions of the federal executive body specially authorized in the field of industrial safety of substations, as well as the conclusions of the commissions that previously carried out technical diagnostics of the substation;
the level of technical maintenance of the substation and compliance of maintenance with the requirements of the instructions and regulations in force at the enterprise;
compliance of repair documentation with the requirements of regulations, GOST normative documents of the owner enterprise and NTD of the federal executive body specially authorized in the field of industrial safety of substations.
8.2. Checking the conditions for technical diagnostics.
8.2.1. When checking the conditions for carrying out technical diagnostics of a lifting structure, the commission should pay attention to the condition of the site on which it is installed.
For rail mounted cranes crane runway and dead-end stops must comply with the passport specifications. A variety of PS - overhead cranes for the period of technical diagnostics should be installed in the area of landing sites, cleared of debris, dirt and snow, and outside zones of technological aggressive influence ( high temperatures, release of chemicals, gas emissions, etc.).
8.2.2. During the period of its technical diagnostics, the installation site of the substation must be fenced with appropriate warning signs, illuminated and accessible for the installation of additional lifting equipment used during diagnostics. On the switch that turns on PS 25, there should be a sign with the inscription: “Do not turn on, people are working.”
8.2.3. In the technical diagnostic zone, the owner of the substation must prepare test loads (with documented weight) for cargo testing of the diagnosed substation.
8.2.4. The substation must be cleaned of dirt, grease, icing, etc., the casing must be removed, the hatches opened, the substation de-energized.
8.2.5. Stairs, railings, fences, hatches must be operational and meet the safety requirements for this type of lifting structures.
8.2.6. The PS must have signs indicating registration number lifting structure, its load capacity and test date. The inscriptions on the plate must be clearly visible from the ground (from the floor) and correspond to the data in the PS passport.
8.2.7. The technical diagnostics area of the substation must be located outside the area of overhead power lines and taking into account other safety requirements.
8.Z. Checking the condition of metal structures.
8.3.1. Checking the condition of substation metal structures is the main type of technical diagnostic work in terms of volume and significance. It includes:
external inspection of load-bearing elements of metal structures;
checking elements of metal structures using one of the types of non-destructive testing (for example, visual measuring control - VIC). Type and necessity of using others additional types non-destructive testing is determined by the commission performing technical diagnostics.
checking the quality of connections of elements of metal structures (welded, bolted, hinged, etc.);
measurement of residual deformations of beams, booms, trusses and individual damaged elements;
assessment of the degree of corrosion of load-bearing elements of metal structures (if there are signs of corrosion).
External inspection and visual inspection should be carried out using simple optical means and portable light sources, with special attention should be paid to the following places where damage may occur:
areas of sudden changes in cross sections;
areas subjected to damage or shock during installation and transportation;
places where significant stress, corrosion or wear occurs during operation;
areas with welded seams, bolted and riveted connections.
cracks in the base metal, welds and near-heat zone, indirect signs of the presence of which are peeling paint, local corrosion, rust stains, etc.;
general and local residual deformations;
delamination of the base metal;
poor quality of repair welded joints;
backlash in hinge joints, loosening of bolted and riveted joints.
8.3.5. Inspection of connecting elements of a metal structure (axles, pins, etc.) should begin with inspection of the condition of the fixing elements, indicating the presence of axial or torsional forces in the connection. When found external signs damage to the connection (shocks, sharp blows, looseness, etc.), the axle (pin) is dismantled and measured. The axle mounting sockets should also be subjected to similar inspection and measurements.
8.3.6. Measurement of residual deformations of beams, booms, trusses and their elements should be carried out in accordance with the recommendations for the types of lifting structures.
8.3.7. When diagnosing metal structures, it should be taken into account that fatigue cracks occur primarily in areas of local stress concentrators, namely in:
attachment points for braces, racks, scarves to belts;
elements with a sharp drop cross sections;
places where linings and ribs end;
areas of holes with untreated, burnt or welded edges;
places where welds intersect;
zones of differences in thickness of joined sheets (joints);
places for re-welding cracks in welding seams and etc.
The choice of the type of non-destructive testing for a specific substation is determined by the commission, and the commission bears full responsibility for undetected cracks, especially in tensile elements of the metal structure.
NDT is carried out by commission members certified in the field of NDT or by specialists from a certified NDT laboratory (in-house or third-party).
8.3.9. When assessing residual deformations of metal structures, it is necessary to pay attention to damage that leads to a decrease in the load-bearing capacity of the structure:
deviation from straightness (towers, booms, spans, racks of truss structure elements);
twisting (of spans, supports, booms, etc.);
misalignment of connections (sections of booms, towers, etc.);
the presence of residual deflections of span beams, brackets, consoles, etc.;
distortion of the shape of spans in plan.
8.3.11. Possible places for corrosion to occur are:
closed spaces (boxes) of spans, running frames, ring beams, belts and pillars of portals;
support units of booms, towers, “legs” (supports) of gantry and portal cranes;
gaps and cracks formed due to loose fitting of elements;
welded joints made with an intermittent seam, etc.
8.3.12. Corrosion zones are plotted on diagrams of metal structures, indicating the extent of damage and coordinates of location. The question of the further operability of an element affected by corrosion is decided on a case-by-case basis. If necessary, the commission's conclusions can be confirmed by calculations of the element taking into account corrosive wear.
8.3.13. Particular attention should be paid to the compliance of the passport data on the steel grades from which the load-bearing metal structures of the lifting structure are made with the actual data. If the metal structure has been subjected to repairs, then the choice of steels for repairs must meet the requirements of the current normative and technical documentation for the temperature range of use of steels.
8.3.14. Repair solutions used to restore the strength (stability, rigidity, etc.) of an element damaged by a crack or residual deformation must correspond to standard repair solutions for this type of damage. In places where there is a high concentration of stress in tensile elements (for example, in the axle-box assemblies of the end beams of bridge cranes), solutions with simple cutting of the edges and subsequent welding of the detected cracks should not be used to repair cracks. In such cases, it is necessary to use additional linings (reinforcements) that reduce the level of stress concentration after completion of the repair of the damaged element, otherwise the repair solution must be rejected.
8.3.15. Repair solutions (both design and technological) used to restore the strength (stability, rigidity, etc.) of a metal structure element made of high-strength steel 26 damaged by a crack or residual deformation must be comprehensively justified in the “Safety Case” document stored together with the crane passport.
8.4. Checking the condition of mechanical equipment
8.4.1. Work to check the condition of substation components and mechanisms includes:
assessment of the compliance of installed equipment with operational documents;
external examination in order to analyze the general condition, performance and the need for further measurements;
carrying out the necessary measurements.
8.4.3. An external examination reveals:
Completeness and general technical condition of all mechanisms, presence of damage to their individual components and parts;
Absence of deformation, corrosion, as well as the subsequent need to eliminate them;
No lubricant leakage;
Compliance with the installation of mechanism components (for example, brakes of the transmission mechanism
Availability and technical condition of safety devices (casings, covers, etc.).
The need for additional disassembly of mechanisms during inspection is determined by the commission.
8.4.4. Damage identified as a result of an external inspection must be measured. The measurement result is compared either with the size where there is practically no defect, or with the size indicated in the drawing.
The need for measurements can be determined during run-in and testing indirect signs(noise, lubricant leak, increase in temperature of the unit, etc.).
8.4.5. The presence of lubrication in the gearboxes is checked using a dipstick, oil level plugs, eyes, or through the hatch in the cover.
8.4.6. When checking mechanisms, you should pay attention to:
cracks in gearbox housings, brake levers, pulleys, pads;
breakage of brake springs;
wear of gears;
wear of running wheels and their positioning;
the presence of backlash in couplings, hinged and keyed joints;
completeness and fastening of bolted connections, especially rotating bearings;
correct installation of brakes, clutches, gearboxes, drums;
correct brake adjustment;
misalignment of the slewing bearing.
8.4.8. The final check of the functionality of the mechanisms is carried out during static and dynamic tests of the lifting structure. At the same time, the following are checked: the smooth operation and reliability of the brakes holding the mechanisms, the absence of runout of pulleys, blocks and drums, the operability and reliability of the slewing bearing, the nature of the noise and temperature in the gearboxes, engines, the correct operation (installation) of wheels for cranes on rails, support races, etc.
8.5. Checking the condition of the rope-block system
8.5.1. The following damage is typical for cable-block systems of lifting structures:
cracks and chips of block flanges;
wear along the stream or flange of blocks and drums;
lack and/or leakage of lubricant in bearings;
defects (damage) in ropes;
absence (damage) of the locking strip in the hook suspension;
displacements in the installation of pulley system blocks;
deviation from the project in reeving and/or sealing the ends of the rope.
8.5.3. Intensively working sections of the rope passing through the largest number blocks or located on equalizing blocks are more often subject to wear and wire breakage.
Ropes of lifting structures transporting molten metal and others dangerous goods, must undergo mandatory magnetic flaw detection.
8.5.4. Both the places where ropes are attached to the drums and the structures of lifting structures are subject to mandatory control. In these places, you should pay attention to the quantity, size compliance and quality of tightening of fasteners.
8.5.5. Hooks and other load-handling elements must comply with the passport specifications and have the appropriate markings of the manufacturers. During the testing of a lifting structure, load-handling elements (grabs, grippers, electromagnets) are subjected to special tests. The results of these tests (with the load-handling device installed on the substation at the time of testing) are included in the substation test report.
8.5.6. Ropes, pulleys, drums and hooks should be checked using the maximum rejection standards for lifting components given in operational documentation and NTD.
8.5.7. During static and dynamic tests of a lifting structure, the rope-pulley system is checked for:
correct rope reeving;
no beating of blocks and drums;
correct winding of the rope on the drum;
reliability of holding the test load, followed by checking the condition of the rope and its attachment points to the drum or metal structure of the lifting structure.
Technical diagnostics- a field of knowledge covering the theory, methods and means of determining the technical condition of an object. The purpose of technical diagnostics in the general maintenance system is to reduce costs at the operation stage by carrying out targeted repairs.
Technical diagnostics- the process of determining the technical condition of an object. It is divided into test, functional and express diagnostics.
Periodic and planned technical diagnostics allows you to:
fulfill input control units and spare parts when purchasing them;
minimize sudden unscheduled stops technical equipment;
manage equipment aging.
Comprehensive diagnostics of the technical condition of equipment makes it possible to solve the following problems:
carry out repairs based on actual condition;
increase the average time between repairs;
reduce the consumption of parts during the operation of various equipment;
reduce the volume of spare parts;
reduce the duration of repairs;
improve the quality of repairs and eliminate secondary breakdowns;
extend the life of operating equipment on a strict scientific basis;
increase operational safety energy equipment:
reduce consumption of fuel and energy resources.
Test technical diagnostics- this is a diagnosis in which test influences are applied to the object (for example, determining the degree of wear of the insulation of electrical machines by changing the tangent of the dielectric loss angle when voltage is applied to the motor winding from the AC bridge).
Functional technical diagnostics- this is a diagnostic in which the parameters of an object are measured and analyzed when it is functioning for its intended purpose or in a special mode, for example, determining the technical condition of rolling bearings by changes in vibration during operation of electrical machines.
Express diagnostics- this is diagnostics using a limited number of parameters in a predetermined time.
Technical diagnostic object- a product or its components subject to (subject to) diagnosis (control).
Technical condition is a state that is characterized at a certain point in time when certain conditions external environment values of diagnostic parameters set technical documentation to the object.
Technical diagnostic tools- equipment and programs with the help of which diagnostics (monitoring) is carried out.
Built-in technical diagnostic tools- these are diagnostic tools that are integral part object (for example, gas relays in transformers for a voltage of 100 kV).
External technical diagnostic devices- these are diagnostic devices made structurally separately from the object (for example, a vibration control system on oil pumps).
Technical diagnostic system- a set of means, object and performers necessary to carry out diagnostics according to the rules established by the technical documentation.
Technical diagnosis- diagnostic result.
Prediction of technical condition This is a determination of the technical condition of an object with a given probability for the upcoming time interval, during which the operational (inoperative) state of the object will remain.
Technical diagnostic algorithm- a set of instructions that determine the sequence of actions during diagnostics.
Diagnostic model- a formal description of the object necessary to solve diagnostic problems. The diagnostic model can be presented as a set of graphs, tables or standards in the diagnostic space.
Exist various methods technical diagnostics:
This is done using a magnifying glass, an endoscope, and other simple devices. This method is used, as a rule, constantly, when conducting external inspections of equipment when preparing it for work or during technical inspections.
Vibroacoustic method implemented using various vibration measuring instruments. Vibration is assessed by vibration displacement, vibration velocity or vibration acceleration. Assessment of the technical condition by this method is carried out by the general level of vibration in the frequency range 10 - 1000 Hz or by frequency analysis in the range 0 - 20000 Hz.
Implemented using . Pyrometers measure temperature in a non-contact manner at each specific point, i.e. To obtain information about the temperature zero, you need to scan the object with this device. Thermal imagers make it possible to determine the temperature field in a certain part of the surface of the object being diagnosed, which increases the efficiency of identifying incipient defects.
Acoustic emission method is based on recording high-frequency signals in metals and ceramics when microcracks occur. The frequency of the acoustic signal varies in the range of 5 - 600 kHz. The signal occurs at the moment of microcrack formation. Once the crack has developed, it disappears. As a result, when using this method apply various ways loading of objects during the diagnostic process.
The magnetic method is used to identify defects: microcracks, corrosion and breaks of steel wires in ropes, stress concentration in metal structures. The voltage concentration is detected using special devices, the operation of which is based on the principles of Barkhausson and Villari.
Partial discharge method used to detect defects in the insulation of high-voltage equipment (transformers, electrical machines). The physical basis of partial discharges is that local charges of different polarities are formed in the insulation of electrical equipment. When charges are oppositely polarized, a spark (discharge) occurs. The frequency of these discharges varies in the range of 5 - 600 kHz, they have different powers and durations.
There are various methods for recording partial discharges:
potential method (partial discharge probe Lemke-5);
acoustic (high-frequency sensors are used);
electromagnetic (partial discharge probe);
capacitive.
It is used to identify defects in the insulation of station synchronous generators with hydrogen cooling and defects in transformers for voltages of 3 - 330 kV. chromatographic analysis of gases. When various defects occur in transformers, various gases are released in the oil: methane, acetylene, hydrogen, etc. The proportion of these gases dissolved in the oil is extremely small, but nevertheless there are instruments (chromatographs) with the help of which these gases are detected in transformer oil and the degree of development of certain defects is determined.
To measure the dielectric loss tangent in insulation in high-voltage electrical equipment (transformers, cables, electrical machines), a special device is used -. This parameter is measured when voltage is applied from rated to 1.25 rated. If the insulation is in good technical condition, the dielectric loss tangent should not change in this voltage range.
Graphs of changes in the dielectric loss tangent: 1 - unsatisfactory; 2 - satisfactory; 3 - good technical condition of insulation
In addition, for technical diagnostics of electrical machine shafts and transformer housings, they can be used following methods: ultrasonic, ultrasonic thickness gauging, radiographic, capillary (color), eddy current, mechanical tests(hardness testing, tensile testing, bending), X-ray flaw detection, metallographic analysis.
Gruntovich N.V.
7. Diagnostics of the technical condition of equipment
7.1. Basic principles of technical diagnostics
Diagnostics- a branch of science that studies and establishes the signs of the state of the system, as well as methods, principles and means by which a conclusion is given about the nature and essence of the system’s defects without disassembling it and the system’s service life is predicted.
Technical diagnostics machines represents a system of methods and means used to determine the technical condition of a machine without disassembling it. Using technical diagnostics, you can determine the condition of individual parts and assembly units of machines, and search for defects that caused the machine to stop or operate abnormally.
Based on the data obtained during diagnostics on the nature of destruction of parts and assembly units of a machine, depending on the time of its operation, technical diagnostics make it possible to predict the technical condition of the machine for the subsequent period of operation after diagnosis.
The set of diagnostic tools, an object and performers operating according to established algorithms is called diagnostic system.
Algorithm- this is a set of instructions that determine the sequence of actions during diagnosis, i.e. the algorithm establishes the procedure for checking the state of object elements and the rules for analyzing their results. Moreover, the unconditional diagnostic algorithm establishes a predetermined sequence of checks, and the conditional one - depending on the results of previous checks.
Technical diagnostics - This is the process of determining the technical condition of an object with a certain accuracy. The result of the diagnosis is a conclusion about the technical condition of the object, indicating, if necessary, the location, type and cause of the defect.
Diagnostics is one of the elements of the maintenance system. Its main goal is to achieve maximum operating efficiency of machines and, in particular, to minimize the cost of their maintenance. To do this, they provide a timely and qualified assessment of the technical condition of the machine and develop rational recommendations for the further use and repair of assembly units (maintenance, repair, further operation without maintenance, replacement of assembly units, materials, etc.).
Diagnosis is carried out both during maintenance and repair.
During maintenance, diagnostic tasks are to establish the need for major or routine repairs of the machine or its assembly units; quality of functioning of mechanisms and machine systems; a list of work that needs to be performed during the next maintenance.
When repairing machines, diagnostic tasks come down to identifying assembly units that need to be restored, as well as assessing the quality of repair work. Types of technical diagnostics are classified according to purpose, frequency, location, level of specialization (Table 7.1). Depending on the vehicle fleet, diagnostics are carried out by the Operating Enterprise or at specialized technical service enterprises.
Diagnostics, as a rule, is combined with maintenance work. In addition, when machine failures occur, in-depth diagnostics are carried out at the request of the operator.
Recently, a network of small enterprises has appeared to provide technical maintenance services for machines, including diagnostics, i.e. diagnostics in this case is removed from the scope of maintenance work and becomes an independent service (product), which is provided at the request of the client both during the operation period and when assessing the quality of repairs, the residual cost of work to restore the functionality and serviceability of machines, as well as when purchasing and sale of used cars.
Diagnostic work at an operating enterprise is carried out depending on the size and composition of the vehicle fleet at a specialized diagnostic site (post) or at a maintenance site (post). The object of technical diagnostics can be a technical device or its element. The simplest object of technical diagnostics will be a kinematic pair or interface. However, the class of objects under consideration can include an aggregate of any complexity. The diagnosed object can be considered in two aspects: from the point of view of structure and method of functioning. Each aspect has features described by its own system of concepts.
Under the system structure a certain relationship is understood, the relative position of the components (elements) characterizing the device and design of the system.
Parameter- a qualitative measure characterizing the property of a system, element or phenomenon, in particular a process. Parameter value- quantitative measure of the parameter.
Objective diagnostic methods give an accurate quantitative assessment of the assembly unit, machine. They are based on the use of both special control and diagnostic tools (equipment, devices, tools, devices), and those installed directly on machines or included in the driver’s tool kit.
Table 7.1
Types of diagnostics and areas of their application
|
Qualifying feature |
Type of diagnosis |
Application area |
Main goals |
|
According to the place of diagnosis By volume By frequency By level of specialization |
Operational Production Partial Planned (regulated) Unscheduled (causal) Specialized Combined |
During maintenance, inspections, failures and malfunctions When repairing cars at repair plants During incoming and outgoing inspection of machines in repair production During technical inspections During periodic maintenance and inspections In the event of failures and malfunctions When servicing machines at service enterprises and by the Central Bureau of Production When repairing machines When servicing machines by the operating enterprise and by the central maintenance department |
Determination of the residual life of assembly units and the need for adjustment work. Establishing the scope and quality of repair work, detecting faults, assessing the readiness of machines for work Determination of the residual life of assembly units. Quality control of repair work Determining the residual life of assembly units, checking the quality of their functioning, identifying a list of adjustment works, preventing failures Determining the list of necessary adjustment work, checking the readiness of machines for operation or the quality of their storage, identifying faults and then eliminating them Prevention of failures, determination of residual life, establishment of a list of adjustment works, checking the quality of service and repair of machines Identification of failures and malfunctions and their subsequent elimination Carrying out diagnostics provided for by TO-3 and after overhaul time |
Determining the residual life of assembly units, checking the quality of repairs
Diagnostics with subsequent maintenance of the machine, checking the need for repairs of machines with the elimination of defects. Detection and elimination of defects when failures occur Objective diagnosis is divided into direct and indirect
Assembly units and the machine as a whole are diagnosed by structural parameters using universal measuring instruments: calibers, probes, scale bars, calipers, micrometers, toothometers, standard gauges, etc. This allows you to obtain accurate results. The disadvantage of this method is that in many cases it requires disassembling the diagnostic object. The latter significantly increases the labor intensity of the work and disrupts the running-in of mating surfaces. Therefore, in practice, direct diagnostics, as a rule, are carried out in cases where the structural parameters of the object being diagnosed can be measured without disassembling the mating surfaces.
Indirect diagnosis - This is the process of determining the actual state of the diagnostic object using indirect, or, as they are called, diagnostic parameters.
Changes in parameters of work processes, structural noise, wear debris content in oil, power, fuel consumption, etc. are used as indirect indicators.
The diagnostic process itself is carried out using pressure gauges, vacuum gauges, piezometers, flow meters, pneumatic calibrators, smoke meters and various special instruments.
