What are the ways to clean parts. Cleaning, flushing and troubleshooting of parts Flushing and cleaning of parts

After disassembling the machine, assembly units and individual parts must be cleaned and washed from dirt, shavings, foreign particles, carbon deposits, grease, coolant in order to identify defects, improve the sanitary conditions of repair, as well as to prepare parts for restoration and painting operations.

Parts cleaning methods:

Mechanical. Rust, old paint, hardened lubricant, carbon deposits, etc. are removed from parts with manual or mechanized brushes, cutters, scrapers, scrapers, various machines.

Abrasive. Cleaning is carried out using sandblasting or hydrosanding the part.

Thermal. Old paint, rust is removed by heating the surface of the part with the flame of a blowtorch or gas torch.

Chemical. Remains of lubricant, cooling liquid, old paint are removed with special pastes and washing solutions, which include caustic soda, quicklime, chalk, fuel oil, etc.

Parts are washed with aqueous alkaline solutions and organic solvents. First in a hot solution, then in clean hot water. After that, the part is thoroughly dried with compressed air and napkins. Parts with elements made of non-ferrous metals, plastics, rubber, fabrics are not washed in alkaline solutions. Parts with polished and sanded surfaces should be washed separately.

Methods for flushing parts:

1. Manual. Washing is carried out in two baths filled with an organic solvent (kerosene, gasoline, diesel fuel, chlorinated hydrocarbons).

2. In tanks by immersion method. Flushing is carried out in a stationary or mobile tank with a mesh on which the parts are laid, and a tube with an electric spiral or a coil for heating the washing solution to a temperature of 80-90 ° C.

3. In washing machines. Stationary or mobile machines of various designs.

4. Ultrasonic. Washing is carried out in a special bath with heated washing liquid (alkaline solutions or organic solvents). The bath houses a source of ultrasonic vibrations that creates elastic waves high frequency, which accelerate the separation of contaminants from the surface of the part.

Fault detection of parts

The cleaned parts are subjected to defect detection in order to assess their technical condition, identifying defects and establishing the possibility of further use, the need for repair or replacement. When flaw detection reveals: wear of working surfaces in the form of changes in the size and geometric shape of the part; the presence of crumbling, cracks, chips, holes, scratches, marks, scoring, etc .; residual deformations in the form of bending, twisting, warping; the change physical and mechanical properties as a result of exposure to heat or the environment.

The flaw detection of the washed and dried parts is carried out after assembling them according to the units, which must be performed carefully and carefully. Each part is first inspected, then its dimensions are checked with an appropriate checking and measuring tool. In some cases, the interaction of a given part with others associated with it is checked.

Defect detection methods:

1. External examination. Allows you to identify a significant part of the defects: holes, dents, obvious cracks, chips, chipping in bearings and gears, corrosion, etc.

2. Check by touch. The wear and crushing of threads on parts, the ease of rotation of rolling bearings and shaft journals in plain bearings, the ease of movement of gears along the splines of the shaft, the presence and relative magnitude of clearances of mating parts, the density of fixed joints, etc. are determined.

3. Tapping. The part is lightly tapped with a soft hammer or hammer handle in order to detect cracks, the presence of which is indicated by a rattling sound.

4. Kerosene test. It is carried out in order to detect the crack and its ends. The part is either immersed in kerosene for 15-20 minutes, or the alleged defective place is smeared with kerosene. Then rub thoroughly and cover with chalk. Kerosene protruding from the crack will moisten the chalk and clearly show the crack boundaries.

5. Measurement. With the help of measuring tools and means, the amount of wear and clearance in the mating parts, the deviation from the specified size, the shape and distance errors of the surface position are determined.

6. Hardness test. According to the results of measuring the hardness of the surface of the part, changes are detected that have occurred in the material of the part during its operation.

7. Hydraulic (pneumatic) test. Serves for detecting cracks and cavities in body parts. For this purpose, all holes in the housing are muffled, except for one, through which liquid is injected under a pressure of 0.2-0.3 MPa. Leaking or fogging walls will indicate a crack. It is also possible to blow air into the housing immersed in water. Air bubbles will indicate an existing leak.

8. Magnetic method. It is based on changing the magnitude and direction of the magnetic flux passing through the part, in places with defects. This change is recorded by applying a dry ferromagnetic powder or suspended in kerosene (transformer oil) to the test part: the powder settles along the edges of the crack. The method is used to detect hidden cracks and pits in steel and cast iron parts. Stationary and portable (for large parts) magnetic flaw detectors are used.

9. Ultrasonic method... It is based on the property of ultrasonic waves to be reflected from the boundary of two media (metal and void in the form of a crack, shell, lack of penetration).

10. Luminescent method. Based on the property of certain substances to glow in ultraviolet rays. A fluorescent solution is applied to the surface of the part with a brush or immersion in a bath.

The list of defects lists in detail the defects of the machine as a whole, each unit separately and each part to be restored and hardened. A correctly drawn up and sufficiently detailed list of defects is an essential addition to the technological processes of repair. Therefore, this very responsible technical paper usually makes up a technologist for the repair of equipment with the participation of the foreman of the repair team, the foreman of the repair shop, representatives of the quality control department and the customer's shop.

The flaw detection of the washed and dried parts is carried out after they have been assembled in units. This operation requires a lot of attention. Each part is first inspected, then its dimensions are checked with an appropriate verification and measuring tool. In some cases, check the interaction of this part with others associated with it.

The list of defects lists in detail the defects of the equipment as a whole, of each unit separately and of each part to be restored and hardened.

When disassembling the equipment to be repaired into units and parts, control and sorting of ero parts into the following groups is carried out: 1) fit for further operation; 2) requiring repair or restoration; 3) unusable, subject to replacement.

Similar information.

The surfaces of most parts disassembled during the repair of vehicle units and assemblies are covered with grease films and asphalt-resinous contaminants. To ensure the necessary sanitary and hygienic working conditions for dismantlers and to increase their productivity, all parts must be thoroughly cleaned and rinsed. The influence of washing and cleaning works on the quality and resource of repaired vehicles and their units is especially great.

So, incompletely removed scale from the outer surfaces of the cylinder liners during vehicle operation worsens the cooling of the cylinders, which can lead to engine overheating and more intensive wear of the parts of the cylinder-piston group. Poor cleaning of the crankshaft channels from resinous deposits impairs oil supply to the shaft journals and liners of the main and connecting rod bearings; this can lead to their accelerated wear. It is much more difficult to weld a crack in a part if the metal is not cleaned of oil and contamination, since, getting into the weld pool, contamination interferes with fusion electrode metal with the main one, the seam turns out to be porous and fragile. On a poorly cleaned part, small cracks can simply not be noticed and the defective part will go to the assembly.

In this regard, the improvement of the technology of cleaning parts during car repairs is given great attention... V recent times more effective detergents have been created, fundamentally new processes for cleaning and washing parts have been developed, production is equipped with more advanced washing machines.

Synthetic detergents (CMC) are widely used at all stages of cleaning. They are based on surfactants, the activity of which is increased by the introduction of alkaline electrolytes.

More often than others, CMC Labomid, as well as MS, are used when cleaning car parts. They are free-flowing white or light yellow powders. They are non-toxic, non-flammable, fireproof and soluble in water. CMC solutions allow the simultaneous cleaning of parts made of ferrous and non-ferrous metals and alloys. Means Labomid-101, Labomid-102 and MS-6 are intended for cleaning parts in jet washing machines, and Labomid-203 and MS-8 - in submersible machines.

In order to further improve the CMC, new compositions of technical detergents Temp-100 and Temp-100A have been developed. These drugs are more effective than Labomid and MS, and, in addition, Temp-100A has an increased passivating effect in relation to the surface to be cleaned, i.e. increases its corrosion resistance.

Working concentrations of CMC solutions depend on the degree of surface contamination and are 5-20 g / l. The best cleaning effect of CMC solutions is observed at temperatures of 75-85 ° C. At temperatures below 70 ° C, the washing ability of the solution sharply decreases and foaming increases.

In addition to synthetic detergents, solvents (diesel fuel, kerosene, unleaded gasoline, white spirit) and dissolving emulsifying agents (Labomid-312, Emulsin, Ritm, AM-15) are also used to clean car parts. Solvents are used to soak blocks and other parts with asphalt-resinous deposits, crankshaft channels, fuel equipment, and degrease surfaces. Dissolving-emulsifying agents are used when cleaning parts from durable asphalt-resinous deposits, as well as in those cases when cleaning takes place at moderate temperatures (20-50 ° C).

It is most difficult to clean parts from carbon deposits and scale, because they contain a large number of insoluble or poorly soluble components, which makes it difficult to remove them.

To remove carbon deposits and scale, a mechanical cleaning method is most often used: with stone chips, metal brushes or circles. The disadvantage of these cleaning methods is manual labor.

Noteworthy is the method of cleaning parts from carbon deposits by annealing. This method was introduced at one of the Moscow auto repair plants when cleaning the combustion chambers of the cylinder heads from carbon deposits. The cylinder heads to be cleaned (made of AL4 aluminum alloy) are immersed in the electric furnace chamber, in which the temperature is maintained at 400-450 ° C. At this temperature, the heads are kept for 15-20 minutes. After that, the cassette with the heads is rolled out of the chamber and the parts are naturally cooled to the ambient temperature. With such annealing, due to the coefficient of linear expansion that is not the same with the metal, the carbon deposits are separated from the surface of the part. After cooling the heads, they are placed in a cabinet equipped with exhaust ventilation and blown with compressed air at a pressure of 0.4-0.5 MPa.

The method of cleaning parts using ultrasound is becoming more and more widespread in the auto repair industry. The advantages of this cleaning method are: high speed cleaning, the ability to use various detergents at room and moderate temperatures, the ability to clean parts with a complex configuration, ease of mechanization and automation of the process. It is most advisable to use ultrasound for cleaning parts with a complex configuration (carburetor casings, gasoline pumps), as well as electrical equipment, rolling bearings, etc.

The parts to be cleaned are placed in a bath with a cleaning solution. Under the action of ultrasound, areas of compression and rarefaction are formed in the washing solution, destroying the contaminants on the surface, which are carried away along with the solution. Aqueous solutions of Labomid or MS with a concentration of 10-20 g / l at a temperature of 55-65 ° C are used as a detergent. When cleaning with the indicated solutions, the surface of the parts is passivated simultaneously with cleaning.

Parts are also cleaned from carbon deposits in a salt solution containing 65% sodium hydroxide, 30% sodium nitric acid and 5% sodium chloride at a temperature of 400 ° C. As a result of chemical action, the carbon is loosened. Technological process includes four operations: melt processing, rinsing in running water, etching in an acid solution and a second rinsing in hot water. The parts are kept in the melt for 5-10 minutes. To neutralize alkali, completely remove oxides and brighten the surface, the parts are treated in an etching solution. The use of the method for cleaning parts in molten salts is advisable at enterprises with a program of more than 5 thousand engines per year.

Continuous improvement of processes and equipment for washing and cleaning parts has led to the creation in our country automated line cleaning of engine parts. The line is equipped with a microprocessor control system. The work is carried out in full automatic mode. The operator only observes and controls it.

Depending on what kind of contamination the parts are carrying, they are sorted during disassembly of the engines and placed in containers along the routes. The role of the worker is reduced to placing the container with parts on the receiving roller conveyor of the line and pressing the button of the route along which the parts in the container should go. The control system of the line remembers the input signal and ensures further execution of all operations in automatic mode. The cradles with containers, following the first route, enter all the tanks of the line sections and the parts contained in them undergo alkaline cleaning, cleaning in solvent-emulsifying agents, acid treatment for descaling and passaging. The parts following the second route pass over the acid bath without sinking into it, since there is no need to descale. Parts following the third route go only into alkaline baths. Exposure of technological modes and control over the correct functioning of all systems are assigned to the control system.

It has been established that providing high-quality washing and cleaning of parts gives a total increase in their overhaul life by 1.0-1.5%.

TO Category:

Repair industrial equipment

Cleaning, flushing and troubleshooting of parts

Cleaning and rinsing parts

After disassembling the machine, the parts and assembly units must be cleaned and washed, since the cleaner the parts, the easier it is to identify defects in them. In addition, cleaning and rinsing contaminated parts improves the sanitary conditions of the repair.

Cleaning and flushing should also be carried out when preparing parts for restoration or painting.

Cleaning of parts of the equipment being repaired is carried out in the following ways: thermal (fire), mechanical, abrasive, chemical.

The thermal method consists in cleaning parts (removing rust and old paint) with a flame (blowtorch or gas torch).

With the mechanical method of cleaning, old paint, rust and hardened layers of oil are removed from the parts with brushes, mechanized cutters, various manual machines and other portable mechanisms.

In the abrasive method, cleaning is carried out mainly by hydro-sandblasting units.

In the chemical method, old paint, grease, oil layers and other contaminants are removed with a special paste or solutions consisting of quicklime, chalk, caustic soda, fuel oil and other components.

Rice. 1. Stationary washing machine

Mechanized washing of parts is carried out in stationary and mobile washing installations under the influence of strong jets formed as a result of the supply of liquid by a pump under a certain pressure.

In fig. 1 shows a stationary washing machine, consisting of a washing chamber, above which there are eight tanks with washing liquid with a volume of m3 each. Seven tanks with pyramidal bottoms, located on both sides of the unit, in addition to their main purpose are also sedimentation tanks. A solution of the following composition is used as a washing liquid: 2-3% soda ash; 0.3-0.5% OP-7 detergent; 2-3% sodium nitrite; the rest is water.

From the tanks, the washing liquid at a temperature of 80 ° C is supplied by a pump under a pressure of 0.6 MPa (6 kgf / cm2) to a pumping hydrant (pipe with 40 nozzles).

The liquid is heated by steam by means of tubular heaters mounted inside the tanks. The used solution flows into a pan with a mesh, from where it is again pumped into the tanks by a special pump.

Across washing chamber passes a closed monorail with eleven suspensions, which are moved using a drive station (not shown in the figure) at a speed of 0.2 m / min.

Rice. 2. Mobile washing machine

Special baskets with loaded parts and assembly units are suspended on suspension hooks using a cantilever beam and an electric hoist. Assembly units and parts are fed into the washing chamber through self-opening and closing multi-leaf doors.

Once a quarter, it is supposed to drain all the washing liquid through the dirt collector, rinse the tanks and fill in a new solution.

To wash parts directly at workplaces, they use mobile washing baths or washing machines, kerosene is used as a washing liquid. Parts are washed by hand in the baths, and this process is mechanized in washing machines.

In fig. 2 shows a mobile washing machine consisting of a trolley with a fixed bathtub, at the bottom of which a net is installed.

A shelf is attached to the side wall of the tub for flushing small parts. The bath is closed with a lid.

A branch pipe is welded to the inclined planes of the bottom of the bath, through which the contaminated liquid is drained into the tank, which has partitions that form sedimentation tanks in the tank. An electric pump is mounted in the tank, which pumps liquid through a pipe and a gas-resistant hose for washing parts.

Troubleshooting details

After flushing, scratches, cracks, potholes are clearly visible on the surfaces of the disassembled parts, and it is possible to measure the parts with the required accuracy during troubleshooting.

Defect detection of washed and dried parts is carried out after they have been assembled into assembly units, which must be performed carefully and carefully. Each part is first inspected, then its shape and dimensions are checked with an appropriate calibration and measuring tool.In some cases, the interaction of this part with others associated with it is checked in order to establish whether it is possible to repair this part or it is more expedient to replace it with a new one.

Information about the parts to be repaired and replaced is entered in the list of defects for equipment repair.

A correctly drawn up and sufficiently detailed list of defects is an essential factor in preparing for repairs. This responsible document is usually drawn up by a technologist for the repair of equipment with the participation of the foreman of the repair team, the foreman of the repair shop, representatives of the quality control department.

During flaw detection, it is important to know and be able to prescribe the values ​​of limit wear for various parts of the equipment and the allowable limit repair dimensions For example, it is allowed to reduce the thread diameter of the lead screws - 8% of the nominal diameter; reduction of the diameters of the necks of shafts, spindles and axles - 5-10% of the nominal diameter; reducing the wall thickness of hollow spindles and axes - 3-5% of the nominal thickness.

Parts are sorted into three groups: first - fit for further operation; the second - requiring repair or restoration; third - unusable, subject to replacement.

The parts that are laborious to manufacture are subject to repair, the restoration of which is much cheaper than the newly manufactured ones. The part to be repaired must have a significant margin of safety, allowing to restore or change the dimensions of the mating surfaces (according to the system of repair dimensions) without reducing (in some cases increasing) their durability, maintaining or improving the operational qualities of the assembly unit and the unit.

Parts must be replaced if the reduction in their size as a result of wear disrupts the normal operation of the mechanism or causes further intensive wear, which leads to the failure of the mechanism.

When repairing equipment, replace parts with extreme wear, as well as with less than acceptable wear, if, according to calculations, they do not last until the next repair. The service life of the parts is calculated taking into account the limiting wear and the intensity of their wear under actual operating conditions.

When troubleshooting, parts must be marked with the serial number of the list of defects, as well as the inventory number of the machine or machine, this facilitates the implementation of further repair operations.

Marking is carried out with stamps, paint, tags, electrograph or acid. Branding is used to fill the designations on the non-working surfaces of unhardened parts. In other ways, both hardened and non-hardened parts are marked. For example, when marking non-hardened parts, a rubber stamp is moistened in a solution of 40% nitric acid, 20% acetic acid and 40% water; when marking hardened parts - in a solution of 10% nitric acid, 30% acetic acid, 5% alcohol and 55% water (for hardened parts); the moistened stamp is applied to the non-working area of ​​the part to be marked. After holding for 1-2 minutes, the surface is neutralized by wiping with a swab dipped in a solution of calcined soda.

Parts that it was decided to replace during troubleshooting are stored until the mechanism is repaired; they may be needed for drawing up drawings or making samples of new parts.

Washing and cleaning of parts

After disassembling machines and assemblies, the parts are cleaned, degreased and washed. Cleaning and washing of parts has a big impact on the quality of a major overhaul. Complete removal of all contaminants improves the quality of troubleshooting, increases the service life of parts, and reduces the appearance of defects. The rational choice of the method of washing and cleaning depends on the type of contamination, size, configuration of parts and places of contamination deposits, economic considerations, but the main factor determining the choice of the method is the type of contamination.

Contamination of road vehicles operating in difficult conditions of road construction can be divided into the following types: deposits of non-fatty origin (dust, dirt, etc.) and oily and mud; leftovers lubricants; carbon deposits; scale; corrosion; technological deposits in the process of repair; deposits of cement mortar and concrete.

Rice. 12. Schemes for hanging a power tool:
a - on a cable with a counterweight; b - on a spring suspension;
1 - counterweight; 2 - wrench; 3 - block; 4 - cable; 5 - lever; b - abutment; 7 - switch

Deposits of non-fatty origin and oily mud are formed on the outer surface of machine parts and assemblies. Dust, dirt during the operation of the machines gets on dry and oily surfaces. Such contaminants can be removed relatively easily.

Residues of lubricants are found on all parts of machines that operate in an oily environment, this is the most common type of contamination, which requires special preparations and cleaning and washing conditions to remove.

Carbonaceous deposits are products of thermal oxidation of lubricants and fuels. They are formed on the parts of internal combustion engines and, depending on the degree of oxidation, are divided into deposits, varnish films, sediments and asphalt-resinous substances, in addition, residues of bitumen and asphalt mix that remain on the outer surfaces of road vehicle parts when working with these materials.

Carbon deposits are formed during the combustion of fuels and oils. The released unburned solid particles adhere to the oil films and gradually sintering, form a layer of carbon deposits on the walls of the combustion chambers, piston crowns, valves, spark plugs and exhaust manifolds.

Lacquer films form when high temperature is applied to thin layers of oil. They are deposited on connecting rods, pistons, crankshafts and other parts.

Sediments formed from the oxidation products of oil, fuel, dust and other particles are a greasy, sticky mass that settles in the oil pan, oil channels, and in the oil filter.

Asphalt-resinous substances are formed under the influence of high temperatures and atmospheric oxygen. Most of these substances are solid particles that are part of the composition, sediments and can have an abrasive effect on parts. Removal of carbon deposits requires special preparations and certain conditions.

Scale is deposited on the internal surfaces of parts of the engine cooling system and is formed as a result of the release of calcium and magnesium salts when the water is heated to a temperature of 70-85 ° C. The thermal conductivity of scale is many times lower than the thermal conductivity of metal, therefore, even a minimal layer of scale significantly worsens the conditions for heat exchange, leads to overheating of engine parts, especially parts of the connecting rod-piston group and cylinders. As a result, the engine power decreases, the consumption of fuel and lubricants increases and the wear rate of parts increases. Descaling is a relatively complex and time-consuming process.

Corrosion - Iron oxide hydrate is formed as a result of chemical and electrochemical destruction of the surfaces of engine cooling system parts and all other metal surfaces.

Technological contamination on parts and assemblies is formed in the process of repair, assembly and running-in of units. These are the remnants of lapping pastes, grinding wheels, metal shavings, etc. They must also be promptly and thoroughly removed, as they can cause intensive wear of the rubbing surfaces of parts.

Sediments of grout and concrete appear on parts during the operation of the machine with these materials and as a result of unsatisfactory Maintenance machines. Removing these deposits is a simple but time consuming process.

Methods for removing contaminants. In the repair industry, the most widespread are the physicochemical, ultrasonic and mechanical methods of washing and cleaning parts.

The physicochemical method of washing and cleaning (jet and in baths) is that contaminants are removed from the surfaces of parts with aqueous solutions of various drugs or special solvents under certain conditions. The main modes of high-quality washing and cleaning with aqueous solutions are: heat cleaning chemical solution (80-95 ° C), a stream or jet of solution at significant pressure and effective detergents.

The ultrasonic method of washing and cleaning is based on the transfer of energy from an ultrasound emitter through a liquid medium to the surface to be cleaned.

Oscillations of 20-30 kHz cause large accelerations and lead to the appearance of small bubbles in the liquid medium, the rupture of which results in hydraulic shocks great strength, destroying carbon deposits on the surfaces of parts within 2-4 minutes, and oil films within 30-40 seconds. In fig. 13 shows an installation for ultrasonic cleaning and cleaning of parts. The PMS-4 type transducer is attached to the bottom of the welded metal pool (Fig. 13, b) and is powered by the UZG-2.5 ultrasonic generator. During operation, the converter (Fig. 13, a) is cooled by running water, which is supplied through the pipeline and drained through the pipeline. The terminal block is used to connect the converter to the generator. When using an aggressive cleaning solution, a vinyl plastic tank is installed in a metal bath, the space between them is filled with water. The parts to be cleaned are suspended in a bath in a grid basket with cells of at least 3X3 mm. The ultrasonic method is used mainly for cleaning small parts of complex configuration (parts of carburetors, fuel pumps, electrical equipment, etc.). For ultrasonic degreasing of parts, a solution of the following composition can be recommended: soda ash -30 g / l; trisodium phosphate -30, emulsifier OP-10 - 5-10 g / l.

Rice. 13. Installation for ultrasonic washing and cleaning of parts:
a - transducer (emitter); b - ultrasonic installation

The temperature of the solution should be 50-55 ° C. The use of ultrasonic washing and cleaning of parts (especially small ones) gives a significant economic effect by speeding up the cleaning process and improving the quality of the repair of the machine as a whole.

The essence of the mechanical method is to manually clean the surface of the part with scrapers, brushes or mechanized stone chips, abrasive and other materials supplied together with air, water or a cleaning solution.

Detergents and preparations. Aqueous solutions of caustic soda (caustic soda), soda ash (sodium carbonate) with an additive of emulsifiers (water glass, laundry soap, trisodium phosphate) and with anticorrosive additives (chromopic, sodium nitrite) and preparations "Tractorin", ML-51, ML-52, "Labamid-101", "Labamid-203", AM-15, MS-6, MS-8 and etc.

Aqueous alkaline solutions are heated to a temperature of 80-95 ° C. With a decrease in the heating temperature to 70 ° C and below, the viscosity of oil deposits remains elevated, which makes it difficult to separate them and deteriorates the quality of washing. Due to the strong corrosive effect, alkaline solutions (with the presence of caustic soda) intended for cleaning parts made of ferrous metals cannot be used for parts made of aluminum alloys. After washing with alkaline solutions, the parts should be rinsed with clean water.

Synthetic preparations "Tractorin", ML-51, ML-52, MS-6 and MS-8 are the most effective detergents produced by chemical industry... The use of these drugs is cost-effective in comparison with expensive caustic soda. Their main advantages over aqueous alkaline solutions are low toxicity, good solubility in water, the possibility of using parts made of ferrous and non-ferrous metals. In addition, after using these preparations, there is no need to rinse the parts with water.

Preparations "Traktorin", ML-51 and MS-6 are used in machines and installations for jet cleaning of parts. The drug ML-52 and MS-8 are used for boiling out parts from strong carbon deposits in baths. The temperature of solutions from these preparations is 70-80 ° C. Duration of degreasing is 8-20 minutes. The concentration of the aqueous solution is 20-30 g / l.

The AM-15 preparation, which is a solution of surfactants in organic solvents (xylene, olizarin oil and oxyethylated alcohol), is used to clean parts from strong resinous deposits in baths, as well as to restore the throughput of coarse filters.

Preparations "Labamid-101" and "Labamid-203" are designed to remove oil and carbon deposits of various parts. "Labamid-101" is used in the form of aqueous solutions of concentration "Labamid-203" is used in the form of aqueous solutions of concentration 25-35 g / l at a temperature of 80-100 ° C in bath-type washing machines.

Rice. 14. Single chamber conveyor machine for degreasing parts:
1 - pumping out pumping unit; 2 - drain manifold; 3 - injection pumping unit; 4- washing chamber; 5 - settling tanks; 6 - apron conveyor

Equipment. The choice of equipment depends on the type of contamination of parts, their size, detergents and the capacity of the repair facility. For washing, degreasing and cleaning parts in the repair industry, conveyor-type jet washers, batch washers, baths and special installations (for cleaning parts from carbon deposits, scale, etc.) are most widely used.

Conveyor-type jet washing machines designed for washing units, assemblies and parts can be one-, two- and three-chamber. Single-chamber machines are designed for washing with water or degreasing with solutions that do not require subsequent rinsing with water. In fig. 14 shows a single-chamber conveyor jet washing machine designed for degreasing parts using non-aggressive solutions ("Traktorin", ML-51, MS-6), eliminating the need for subsequent rinsing of parts. The washing device for this machine is made in the form of a pumping hydrant. The movement of parts is carried out by a plate-type conveyor. The speed of the conveyor belt is 0.1-0.6 m / min. The washing solution in this machine is heated with steam to a temperature of 75-85 ° C. Large parts are placed directly on conveyor plates, while small parts are fed into the washer in mesh baskets.

Two-chamber machines are used for washing parts and assemblies with alkaline solutions in the first chamber, followed by washing with hot water in the second.

Three-chamber machines have three washing zones. In the first zone, dirt is softened with the help of a washing solution, in the second they are thoroughly washed and in the third they are rinsed with hot water. ... Conveyor-type machines are economically feasible to use at large repair enterprises.

In batch washers, parts are washed with one solution followed by rinsing with hot water. In the latter case, there are two baths: for the detergent solution and hot water. These machines are used in small repair enterprises and repair shops of operational farms.

Baths are the simplest washing installations. Most often they are used to digest parts in alkaline or acidic solutions. Baths are made of steel; they consist of two compartments, one for the cleaning solution and the other for water. From above, the bath is closed with a double-leaf lid.

Cleaning parts from carbon deposits. Parts can be cleaned from carbon deposits by mechanical and physicochemical methods.

Removal of carbon deposits by a mechanical method can be carried out using metal brushes and scrapers, stone chips, hydro-sandblasting. When applying brushes to scrapers, it is not always possible to completely remove carbon deposits from surfaces that are in hard-to-reach places of the part. In addition, after removal of carbon deposits on the smooth surfaces of parts, risks are formed, which during operation serve as foci of carbon deposits. Cleaning parts from carbon deposits with metal brushes and scrapers, due to its simplicity, has become widespread in repair shops of road construction organizations. At large repair enterprises, the cleaning of parts from carbon deposits with stone chips (crushed cherry and apricot pits) is widely used. This method is used to remove carbon deposits from pistons, block heads, exhaust manifolds. Its essence lies in the fact that a crushed shell of fruit seeds is fed to the part under an air pressure of 0.4-0.5 MPa (4-5 kgf / cm2). Striking the surface of the part, it cleans the carbon deposits. In fig. 15 shows the design of the installation for cleaning parts with bone chips. Dry stone chips are poured into the tank through the door. Then it enters the hopper through the mesh and the valve, and from there into the mixer. The valve is opened at the right time using a lever. Air is fed through a tube into the mixer, which carries the crumb into the sleeves to the tips. The amount of air entering the mixer is controlled by a valve, which is operated from a pedal. The parts to be cleaned are placed on a revolving table. The worker, through the holes in the front door, inserts his hand into the protective sleeve and, taking the tip, directs a stream of stone chips to the part, observing the cleaning process through the sight glass.

Rice. 15. Installation for cleaning parts with stone chips

The working chamber is illuminated by a lamp. Dust, crumbs and carbon particles are sucked out through the nozzle using a fan. If the valve is clogged with crumbs, then it is cleaned with compressed air supplied to it through the pipe, when the valve is opened. This method economical, productive and high quality. For example, to clean a set of parts from one D-54A engine from carbon deposits, 4-5 kg ​​of stone chips are consumed, which is 15-20 kopecks in monetary terms, the duration of cleaning is 30 minutes. Due to the fact that the crumb is deformed upon impact, no scoring or scratches remain on the cleaned surface of the part.

It is economically expedient to clean small parts (valves, pushers, springs, etc.) from carbon deposits by chemical means. In this case, the parts are loaded into a bath with an alkaline solution, which consists of caustic and soda ash, liquid glass, laundry soap and water. The parts are kept in this solution for 3-4 hours at a temperature of 90-95 ° C and, after softening, the carbon deposits are removed with hair brushes or rags. After cleaning, the parts are rinsed in cold and hot water.

Rice. 16. Machine for descaling:
1 - bath; 2 - cover; 3 - roller conveyor; 4 - electric motor; 5 - special pump; 6 - electric heating device

Descaling parts. Cleaning of the water jacket of engine blocks and cylinder heads is carried out in special installations. In fig. 16 shows the installation for descaling the water jacket of the unit. The unit is installed on roller conveyor 3 and by means of a hose connected to the side flange of the unit, a solution of tri-sodium phosphate heated to 60-80 ° C is pumped through its jacket at the rate of about 3-5 kg ​​per 1 m3 of water. Can be used for descaling and 8-10% solution of hydrochloric acid... To protect the inner surfaces of parts from corrosion, 3-4 g of urotropine per 1 liter are added to the solution as an inhibitor. The solution is heated to 50-60 ° C. The duration of flushing, depending on the thickness of the scale layer, can be in the range of 10-70 minutes. After descaling, the internal cavities of the parts must be rinsed with clean water.

During the operation of machines, contaminants are deposited on the outer and inner surfaces of parts, differing in composition, properties, adhesion strength to the surface of parts. Contamination reduces the stability of protective coatings, increases the rate of corrosion processes, and reduces the level of maintenance and repair culture. Poor-quality cleaning work during repair reduces the post-repair resource by 20-30%. Complete removal of all contaminants significantly improves the quality of defect detection and restoration of parts, and allows to increase labor productivity in disassembly and assembly works by 15-20%.

For complete removal of contaminants at repair enterprises, multi-stage cleaning of parts is used. Cleaning work, in addition to the external washing of the machine upon admission for repair, includes the cleaning of the disassembled machine and assembly units, parts cleaning before flaw detection, parts cleaning before assembling units, washing before painting. The choice of the cleaning method largely depends on the nature of the contamination, the places of their deposition, the size and shape of the parts. The main factor determining the choice of the cleaning method is the type of contamination.

Repaired machines can have the following types of contamination:

• deposits of non-fatty origin (dust, dirt, plant residues), residues of pesticides and oily and mud deposits
• residues of lubricants
• carbon deposits (carbon deposits, varnish films, sediments, asphalt-resinous substances)
• scale
• corrosion products, paint residues
• technological contaminants that appear during repair, assembly and running-in (metal shavings, remnants of lapping pastes, wear products of grinding wheels, etc.)

The most widespread in the repair of cars are following ways cleaning:

• mechanical
• physico-chemical
• thermal

In addition, specialized repair enterprises use electrochemical, ultrasonic and thermochemical methods.

Detergents

Deposits on the outer surfaces of non-fatty origin are usually removed with a stream of water heated to a temperature of 70-80 ° C. A 1-2% caustic soda solution is used to remove residual lubricants. However, it is ineffective, and an increase in concentration of more than 6% causes corrosion of metals. In addition, caustic soda solution is harmful to human skin.

In recent years, synthetic detergents (CMC) such as MS, Labomid, Temp, and others have been used to clean surfaces. Detergents are mixtures of alkaline salts and surfactants. They are non-toxic, non-flammable and explosion-proof. They can be used to clean ferrous and non-ferrous metal parts. Surfactants are organic compounds that destroy fatty films, prevent re-deposition of contaminants, and create stable emulsions in contact with the aqueous component of the washing solution. These substances speed up the cleaning process. Detergents MS-6, MS-16, MS-18 are mainly used to remove oil-mud, resinous deposits in machines with jet and circulation cleaning of assembly units and machine parts. The concentration of solutions is 15-25 g / l at a temperature of 75-85 ° C, MS-8 and MS-15 - during jet and immersion cleaning from strong carbon deposits. The concentration of solutions is 20-25 g / l, temperature is 80-100 ° C.

Synthetic detergents "Labomid-101" and "Labomid-102" are used to remove oil-mud and asphalt-resinous deposits during blast cleaning. The concentration of solutions is 10-15 g / l at a temperature of 70-85 ° C. "Labomid-203", similarly to MC-8, is used to remove light asphalt-resinous deposits during submerged cleaning, since it is characterized by increased foaming. The concentration of solutions is 20-30 g / l, temperature is 80-100 ° C. "Labomid-315" is used for cleaning from durable asphalt-resinous deposits in baths without heating (15-20 * C) and without mechanical action.

Preparations "Temp-100" and "Temp-YOA" are mixtures of alkaline salts, surfactants and passivators. They are used for jet cleaning of parts and assembly units from oil and mud deposits and protection of the cleaned surface from corrosion (passivation). The concentration of solutions is 10-15 g / l, temperature is 80-95 "C.

Detergents "Complex" and DIAS are intended for jet and steam jet cleaning of machines from pesticides. The concentration of the solutions is 5-6 g / l, the temperature is 80-90 ° C (with a steam jet 95-100 ° C).

Organic preparations AM-15 and "Rhythm" are intended for cleaning engine parts from durable resinous deposits by the immersion method in baths.

AM is a surfactant solution in organic solvents. It is toxic, fire and explosive. Its temperature should not exceed 40 "C. The "Rhythm" preparation is made on the basis of chlorinated hydrocarbons.

For cleaning parts, organic solvents are used (gasoline, kerosene, acetone, alcohols, etc.), mixtures of organic solvents and acid solutions - aqueous solutions of inorganic and organic acids.

Cleaning of parts from carbon deposits, scale can be carried out in molten salts and alkalis in a bath at a temperature of 400-450 "C.

Parts cleaning equipment

In the CRM of farms, in regional workshops general purpose for cleaning assembly units and parts, mainly single-chamber jet washing machines OM-1366G-01, OM-837G, OM-4610-01, etc. are used. By their design, they are approximately the same, they consist of a washing chamber, a pull-out table (loading cart) for placing cleaned assembly units and parts with a total weight of 0.6 to 1.5 tons and baths for the cleaning solution. The wash chambers are equipped with a movable shower device or a rotating loading table. The washing solution is heated to a temperature of 75-85 "With an electric or fire device. The pressure of the jet in shower devices in the range of 0.4-0.5 MPa is created by a centrifugal pump.

For cleaning parts and small-sized assembly units at the areas of engine repair, maintenance of machines in TsRM, submersible washing machines ORG-4990B, OM-9Yu1 or OM-281-OI are used. Productivity of the ORG-4990B machine - 0.4 t / h; the volume of the washing solution is 0.1 m3. A turbulator is installed on the machine to create a flooded stream of solution, which speeds up the cleaning process of parts.

Removal of solid deposits. Solid deposits include carbon deposits, scale, corrosion products and paintwork.

Carbon deposits are removed by mechanical, thermal and thermochemical methods. The mechanical method includes:

• cleaning surfaces with a scraper
• metal brush
• stone crumbs
• sandblasting
• waterjet treatment

Good results are obtained by cleaning carbon deposits and scale by blowing with stone chips (from the shell of stone fruits) on the OM-3181 installation. Before cleaning, the parts are degreased so as not to contaminate the crumb.

The thermal method is used to remove carbon deposits from the exhaust and suction manifolds with excess oxygen or to heat parts in thermal furnaces.

The thermochemical method for removing carbon deposits and scale from parts made of ferrous metals is to immerse them in a melt of salts and alkalis.

Descaling can also be done mechanically and chemically. Steel, cast iron parts are descaled by immersion in a solution consisting of 100-150 g / l of 8-9% hydrochloric acid, followed by rinsing in hot water. Parts made of aluminum alloys are cleaned in a 6% solution of lactic acid at a temperature of 40 ° C.

Corrosion is removed mechanically or chemically. In the first case, the parts are cleaned with steel brushes, emery paper by hand or with special devices, and subjected to sandblasting or abrasive liquid processing. In the chemical method, solutions of sulfuric, hydrochloric or phosphoric acids are used. Corroded surfaces are recommended to be treated with a corrosion modifier before painting.

Rice. Scheme of the OM-1366G-01 washing machine: 1 - fan motor; 2 - air suction branch pipe; 3 - cable; 4, 9 - pipelines; 5 - camera; 6 - electrical cabinet; 7 - room wall; eight - fuel tank; 10 - pump; 11 - filter; 12 - bath; 13 - hatch.

The paint from the cabins and empennage of cars is removed mechanically and chemically. The mechanical method (cleaning with steel scrapers and brushes) is used in the CRM of farms. The chemical method is more effective, in which the surface is treated with a special wash. The paint swells and separates from the metal surface, so it can be easily cleaned with brushes. Washes SD, SP-6, AFT-1, etc. are used.