Cleaning parts and surfaces of assemblies and assemblies is a necessary procedure to maintain mechanisms in working condition. In addition, cleaning maintains the degree of performance at the required technological level, and is also an important tool in identifying defects and the degree of deterioration of engines and their individual components.
In this way, this procedure gives a variety of effects. The presence of different methods and detergents allows you to choose the best ways to clean parts in a particular case.
Cleaning parts with traditional methods
Traditional cleaning technologies include the use of the most common means, such as kerosene and gasoline, to remove contaminants. These are hydrocarbons similar in action with a pronounced toxic effect, which allows you to clean units and various components. Toxic components literally “corrode” scale and dirt, as well as deposits of fuel oil and technical oils.
The undoubted advantages of using these substances include their availability. Gasoline, and sometimes kerosene, are common substances that can be found in any garage or on any industrial enterprise. But this is where the advantages of this method of cleaning parts end, at the same time, the list of negative factors includes several points. Among them are:
- Danger to the health of the worker and to the health of all those around him who are in the room. When heated, kerosene begins to release toxic volatile substances, the inhalation of which can lead to chronic or acute diseases of the lungs, liver, and heart. The same applies to gasoline, but its volatile properties are manifested even in a cold state. A person develops symptoms similar to those of alcohol intoxication, which can lead to pulmonary edema or, for example, cardiac arrest. In addition, if these substances come into contact with the skin or mucous membranes of the organs of vision and breathing, they will cause redness, burning, etc. Therefore, when working with gasoline and kerosene, it is necessary to use protective equipment - rubber gloves, respirators or cotton-gauze bandages, goggles and special clothing. The same applies to other workers in such a room. In addition, the room where this method of cleaning parts is used must be well ventilated or equipped with a powerful ventilation system.
- Danger for the environment. Gasoline and kerosene should be kept away from sun rays and heating elements in tightly closed containers. Disposal of waste liquids must be carried out taking into account their high toxicity.
- The need to adhere to the strictest security measures. Any spark can cause a fire and even an explosion, therefore, when working with gasoline and kerosene, do not smoke, use open flames, etc.
The high level of danger and the difficulty of working in cramped conditions make these substances inconvenient and ineffective when used as detergents.
Cleaning parts with innovative methods
To innovative ways Cleaning parts refers to the technology of applying ultrasound. This method allows you to clean components and assemblies using non-linear effects, the most important of which is cavitation erosion. Cavitation means the formation of tiny bubbles in a bath with a part immersed in an aggressive washing liquid, which, when collapsed, destroy contaminants. This technology is more environmentally friendly than the technology of processing units with gasoline or kerosene, but its use also leads to the appearance of volatile substances.
There are other negative aspects as well:
- The ultrasonic device has a rather complicated device and high cost. This leads to high maintenance and repair costs.
- If multiple cleaning steps are required, the worker will have to manually move the parts crate between baths. If set for this production line, it will also lead to an increase in the cost of the process.
- Ultrasound increases the physico-chemical reactions in an aggressive detergent. If you choose the wrong mode or composition, instead of cleaning from contaminants, the worker can damage the part. That is, ultrasonic technology requires a highly qualified specialist.
Of course, this technique better and more efficient than gasoline cleaning, but there is an even simpler, more effective and less expensive way to get the engine, mechanisms and their individual components in a perfectly clean condition.
The unique way to clean parts from IBS Scherer
The German developer - concern IBS Scherer GmbH has been operating on the market for 50 years and is a leading manufacturer of safe and effective detergents and equipment for cleaning parts. The company's product range includes a large number of options for washing machines and compositions with pronounced properties, which makes it possible to choose the best option without the presence of a specialist.
The development of a German company is as simple as possible:
- The equipment consists of a portable pump, footswitch, hose, brush, washer and reservoir. A minimum of parts allows you to work without training and special knowledge, in addition, simplicity reduces maintenance costs and increases the mobility of installations.
- Detergents have different characteristics, for example, they can apply an anti-corrosion oil film on the parts and include flavors in their composition. They also have different freezing, drying temperatures, and other features.
When working, it uses closed-cycle technology, which allows the use of one tank with a harmless to humans and the environment, but effective detergent composition for one year.
More details about IBS Scherer technologies can be found in the relevant sections, and for more details, it is better to contact our professional consultants in any convenient way.
After disassembling the machine, the assembly units and individual parts must be cleaned and washed from dirt, chips, foreign particles, soot, grease, coolant in order to identify defects, improve sanitary conditions repairs, as well as to prepare parts for restoration and painting operations.
Parts cleaning methods:
Mechanical. Rust, old paint, hardened lubricant, soot, etc. are removed from parts with manual or mechanized brushes, cutters, scrapers, scrapers, and various machines.
Abrasive. Cleaning is carried out using sandblasting or hydrosandblasting of the part.
Thermal. Old paint, rust is removed by heating the surface of the part with the flame of a blowtorch or gas burner.
Chemical. Remains of lubricant, coolant, 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. In alkaline solutions, parts with elements made of non-ferrous metals, plastics, rubber, fabrics are not washed. Parts with polished and ground surfaces should be washed separately.
Parts washing methods:
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. Washing is carried out in a stationary or mobile tank with a grid 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. Rinsing is carried out in a special bath with heated washing liquid (alkaline solutions or organic solvents). A source of ultrasonic vibrations is placed in the bath, which creates high-frequency elastic waves that accelerate the separation of contaminants from the surface of the part.
Parts detection
Cleaned parts are subjected to fault detection in order to assess their technical condition, identify defects and determine the possibility of further use, the need for repair or replacement. During fault detection, the following are revealed: wear of working surfaces in the form of changes in the dimensions and geometric shape of the part; the presence of crumbling, cracks, chips, holes, scratches, scratches, scuffs, etc .; residual deformations in the form of bending, twisting, warping; change in physical and mechanical properties as a result of exposure to heat or the environment.
The detection of washed and dried parts is carried out after they are assembled according to the nodes, which must be done 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 this part with others associated with it is checked.
Methods for detecting defects:
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 tear 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 size of gaps in mating parts, the density of fixed joints, etc. are determined.
3. Tapping. The part is lightly tapped with a soft hammer or hammer handle to detect cracks, the presence of which is indicated by a rattling sound.
4. Kerosene test. It is carried out in order to detect a crack and its ends. The item is either immersed in kerosene for 15-20 minutes, or the alleged defective place is lubricated with kerosene. Then carefully wipe and cover with chalk. Kerosene protruding from the crack will moisten the chalk and clearly show the boundaries of the crack.
5. Measurement. With the help of measuring tools and means, the amount of wear and gap in the mating parts, the deviation from the specified size, the errors in the shape and position of the surfaces are determined.
6. Hardness test. Based on the results of measuring the surface hardness of the part, changes that have occurred in the material of the part during its operation are detected.
7. Hydraulic (pneumatic) test. Used to detect cracks and cavities in body parts. For this purpose, all openings in the body are muffled, except for one, through which fluid is injected under a pressure of 0.2-0.3 MPa. Leaking or fogging of the walls will indicate the presence of a crack. It is also possible to inject air into the housing immersed in water. The presence of air bubbles will indicate an existing leak.
8. Magnetic way. It is based on a change in the magnitude and direction of the magnetic flux passing through the part in places with defects. This change is recorded by applying ferromagnetic powder to the tested part in dry or suspended form in kerosene (transformer oil): the powder settles along the edges of the crack. The method is used to detect hidden cracks and cavities 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. It is based on the property of some substances to glow in ultraviolet rays. A fluorescent solution is applied to the surface of the part with a brush or by immersion in a bath.
The list of defects lists in detail the defects of the machine as a whole, each node separately and each part to be restored and hardened. A correctly compiled and sufficiently detailed list of defects is an essential addition to the technological repair processes. Therefore, this very important technical document is usually compiled by the technology 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 shop.
Detection of washed and dried parts is carried out after they are assembled by units. This operation requires a lot of attention. Each part is first inspected, then its 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.
The list of defects lists in detail the defects of the equipment as a whole, each unit separately and each part to be restored and hardened.
When disassembling the equipment to be repaired into components and parts, the control and sorting of the ero parts into the following groups is carried out: 1) suitable for further operation; 2) requiring repair or restoration; 3) unusable, subject to replacement.
Similar information.
Washing the parts before the start of the repair of the car contributes to the high quality of its repair. When repairing, for example, a car engine, manual washing and automatic washing are used. Hand washing is usually done at small repair shops. Using a manual sink, the part or assembly is installed on a special pallet. A sink is created with a detergent and a brush. Gasoline, kerosene or soda solution is used as a detergent.
Gasoline is a less successful cleaning fluid. Its disadvantage is the highest vapor volatility. And this is related to its toxicity. Gasoline is especially unsafe when working indoors. Gasoline vapors in general aggravate environment. Gasoline does not completely wash off small particles of dirt or abrasive dust after repairing parts. Gasoline has a negative effect on the cuffs and seals of parts and assemblies that are made of rubber. The only advantage of gasoline is that oil pollution quickly dissolves in it. After degreasing parts with gasoline, from time to time you can find any flaws on their surface.
Vapors of kerosene, unlike gasoline vapors, are actually not volatile. The washing characteristics of kerosene are significantly worse than those of gasoline. After washing in kerosene, the parts remain oily. By this they are quite "attract" dust particles. Therefore, kerosene during repairs can only be used as an auxiliary substance.
Soda solution differs from gasoline and kerosene in that it is non-toxic and completely harmless. True, it has an irritating effect on the skin of the hands. Its disadvantage is that it is effective only when heated. If the details of a complex configuration and at the same time are very dirty, then the soda solution will be difficult to wash off. And in duralumin parts, it causes corrosion. In small workshops it is used occasionally. He asks for heating and frequent changes of solution.
Other detergents are also used. In large repair shops, manual washing is not used so extensively due to low productivity. For this reason, washing installations are used at medium and large repair enterprises. These installations provide washing of parts with heating and the upcoming cleaning of the dirty solution. Installations have the highest efficiency. But manual washing cannot be completely excluded from the repair process, since very dirty parts are still subjected to preparatory cleaning by hand.
Washing is a series of operations that are performed in the following sequence:
1) the external surfaces of the parts are cleaned from dirt;
2) clean the internal cavities and channels of parts from carbon deposits and wear particles;
3) the surfaces of the sealing parts are washed;
4) wash the parts themselves;
5) purge the internal channels and dry the parts.
At different washing steps, also depending on the contamination of the parts, different detergents are used. If the engine is very dirty on the outside, then mechanical cleaning of the surface is usually done first with steel brushes. Such brushes are also used for preparatory cleaning of the internal channels of parts from carbon deposits. Cleaning is done very carefully so as not to throw the deepest scratches on the surface.
It happens that after washing the parts, it is necessary to re-do mechanical cleaning. In order to soften the dirt, they are usually dipped in a washing solution beforehand. It happens that blowing out the internal channels is enough to clean dirt and chips. Compressed air is used for blowing. Increased attention should be paid to the intake manifold of the motor, which is damaged. It is not necessary to wash parts that have closed rolling bearings. Together with the detergent, dirt can get into such bearings. The detergent can completely wash away the grease. And this leads to a quick failure of the bearings.
Very dirty external surfaces of such units must be wiped with a rag, which is slightly moistened with washing liquid. Despite the importance of the process of washing parts, in practice, washing is often neglected. Car parts are sometimes not washed at all, and if they are, then somehow. This happens due to a complete misunderstanding of the processes that occur in the car. And the consequences of such a misunderstanding can be quite severe. AT own article"Washing and cleaning of car parts" we tried to explain to you the full significance of this process.
Contaminants of various compositions are deposited on the outer and inner surfaces, they reduce the stability of protective coatings, and increase the rate of corrosion processes. Complete removal of all contaminants increases productivity by 15-20%. Multi-stage cleaning of parts is used. Includes cleaning under disassembled machine, cleaning before defecation, cleaning before reassembly, and washing before painting.
The choice is made on the nature of pollution, there are the following types of pollution:
1) Deposits of non-greasy origin (dust, dirt, plant residues).
2) Residues of pesticides and oily mud deposits.
3) Residues of oily materials.
4) Carbon deposits. (soot, varnish films, asphalt, resinous substances, scale.)
6) Remains of paintwork materials.
7) Technological pollution that appears during repair (metal shavings, lapping phase residues, product residues after grinding.)
The following cleaning methods:
1) Mechanical.
2) Physical thermal.
3) Thermal
4) Specialized
5) At special enterprises. Ultrasonic, thermochemical
Detergents.
Remove with a stream of water, which can be heated up to t 80 degrees. To remove lubricants, a 1-2% solution of caustic soda is used. To clean surfaces, I use synthetic detergents, such as MS, labomid, T. They are mixtures of alkali salts and surfactants. They are non-toxic, non-flammable and non-explosive. Surfactants - organic compounds that ensure the destruction of fatty films, preventing the re-deposition of contaminants. When in contact with water, an emulsion is obtained, that is, a detergent. Detergents such as MS 15, MS 16 are used to remove oily mud, resinous deposits.
These products are used in special machines with jet and circulation cleaning. Tools such as MS 8, MS 15 are cleaned of strong carbon deposits. Temperature up to 100 degrees. Such synthetic detergents as labomid 101, labomid 102 are used to remove oil-mud and asphalt-tar deposits. Concentration 20/30 g per liter of water, temperature up to 100 degrees, without mechanical action. Preparations such as TEM 100, TEM 100 A are alkaline salts used for jet cleaning, oil and mud, protection of the cleaned surface from corrosion, passivation. Organic solvents are also used. Mixtures of organic solvents and acid solutions. Cleaning of parts from soot, scale can be carried out in molten salts.
Cleaning equipment.
General purpose. Single-chamber jet washing machines OH-1366G, OH-837G, OH-4610 are used, they consist of washing chambers, a sliding table for placing parts, parts from 0.6 to 1.5 tons are usually used. Jet pressure 0.4-0.5 MPa. Cleaning of small parts is carried out by submersible washing machines ORG-4990, OM-9101. A turbulator is installed on the machine to create a flooded solution flow.
Removal of hard deposits.
These include soot, scale corrosion products and paint coatings. Carbon deposits are removed by mechanical thermal thermochemical method. Mechanical methods include cleaning the surface with a scraper. With a metal brush, stone brooch, sandblasting and waterjet processing are also included here. Cleaning with a stone brooch shows a good result, before cleaning the part must be degreased, this is done in order not to contaminate the brooch.
The thermal method is used to remove carbon deposits in exhaust and suction manifolds with excess oxygen or heat parts in thermal furnaces, removing carbon deposits and scale from black metal parts consists in immersing them in a melt of salts and alkalis. Descaling can be done mechanically and chemically. Steel cast iron parts are descaled by immersion in a hydrochloric acid solution, followed by rinsing in hot water. Parts made of aluminum or aluminum alloys cleaned in a 6% lactic acid solution at a temperature of 40 degrees, corrosion is removed mechanically and chemically.
In the first case, brushes are used, subjected to abrasive or sandblasting, with chemical methods, solutions of sulfuric hydrochloric and phosphoric acids are used. The paint from the empennage cabins is also removed mechanically and chemically. The chemical method is more effective, the surface is treated with a special wash, the paint swells and separates from the metal surface. Washes SD, SP6, AFT1 and others are used.
Washing and cleaning parts
After disassembly of machines and units, the parts are subjected to cleaning, degreasing and washing. Cleaning and washing parts has a big impact on the quality of the 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 pollution, size, configuration of parts and places of deposits of pollution, economic considerations, but the main factor determining the choice of method is the type of pollution.
Pollution of road machines operating in difficult conditions of road construction can be divided into the following types: deposits of non-fatty origin (dust, dirt, etc.) and oily-mud deposits; lubricant residues; carbon deposits; scale; corrosion; technological deposits in the process of repair; deposits of cement mortar and concrete.
Rice. 12. Schemes for hanging a mechanized tool:
a - on a cable with a counterweight; b - on a spring suspension;
1 - counterweight; 2 - wrench; 3 - block; 4 - cable; 5 - lever; b - emphasis; 7 - switch
Deposits of non-fat origin and oily mud are formed on the outer surface of machine parts and assemblies. Dust, dirt during the operation of machines fall on dry and oily surfaces. Such contaminants are relatively easy to remove.
Lubricant residues are found on all parts of machines that operate in an oily environment; this is the most common type of pollution, the removal of which requires special preparations and cleaning and washing conditions.
Carbon 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 soot, varnish films, precipitation and asphalt-resinous substances, in addition, carbon deposits include bitumen and asphalt concrete mixture residues that remain on the outer surfaces of road machine parts during operation. them with these materials.
Carbon deposits are formed during the combustion of fuels and oils. The unburned solid particles released adhere to the oil films and gradually sinter, forming a layer of soot on the walls of the combustion chambers, piston crowns, valves, candles and exhaust manifolds.
Lacquer films are formed when high temperatures are applied to oil layers of small thickness. They deposit on connecting rods, pistons, crankshafts and other parts.
Sediments formed from the products of oil oxidation, 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 sediment and can have an abrasive effect on parts. To remove carbon deposits, special preparations and certain conditions are required.
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 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, so even a minimal layer of scale significantly worsens the conditions for heat transfer, leads to overheating of engine parts, especially parts of the connecting rod and 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 parts of the engine cooling system and all other metal surfaces.
Technological pollution on details and knots are formed in the course of repair, assembly and running-in of units. These are the remains of lapping pastes, grinding wheels, metal chips, etc. They also need to be removed in a timely and thorough manner, as they can cause intense wear of the rubbing surfaces of parts.
Deposits of cement mortar and concrete occur on the 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 physico-chemical method of washing and cleaning (jet and in baths) is that contaminants are removed from the surfaces of parts with aqueous solutions of various preparations or special solvents under certain conditions. The main modes of high-quality washing and cleaning with aqueous solutions are: high temperature of the washing chemical solution (80-95 ° C), flow or jet of the solution at significant pressure and effective detergents.
The ultrasonic washing and cleaning method 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, upon rupture of which high-power hydraulic shocks occur, destroying carbon deposits on the surfaces of parts within 2-4 minutes, and oil films within 30 minutes. - 40 s. On fig. 13 shows the setting for ultrasonic cleaner and cleaning parts. The PMS-4 transducer is attached to the bottom of the welded metal pool (Fig. 13, b) and receives power from the ultrasonic generator UZG-2.5. 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 hung in the bath in a slatted basket with meshes 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 parts cleaning:
a - converter (emitter); b - ultrasonic unit
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 economical effect by speeding up the cleaning process and improving the quality of machine repair 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.
Washing liquids and preparations. As washing liquids, aqueous solutions of caustic soda (caustic soda), soda ash (sodium carbonate) with the addition of emulsifiers (liquid glass, laundry soap, trisodium phosphate) and anti-corrosion additives (chromic, sodium nitrite) and Traktorin, ML- 51, ML-52, "Labamid-101", "Labamid-203", AM-15, MS-6, MS-8, etc.
Aqueous alkaline solutions are heated to a temperature of 80-95 °C. When the heating temperature drops to 70 °C and below, the viscosity of oil deposits remains elevated, which makes it difficult to separate them and impairs the quality of washing. Due to the strong corrosive effect, alkaline solutions (with the presence of caustic soda) intended for washing 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 Traktorin, ML-51, ML-52, MS-6 and MS-8 are the most effective detergents produced by chemical industry. The use of these preparations is economically advantageous in comparison with expensive caustic soda. Their main advantages over aqueous alkaline solutions are low toxicity, good solubility in water, and the possibility of being used for 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 washing of parts. The preparation ML-52 and MS-8 is used for boiling out parts in baths from strong carbon deposits. The temperature of solutions from these preparations is 70-80 °C. Duration of degreasing 8-20 min. 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 ethoxylated alcohol), is used to clean parts from strong tar 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 with a concentration of "Labamid-203" is used in the form of aqueous solutions with a concentration of 25-35 g / l at a temperature of 80-100 ° C in bath-type washing machines.
Rice. 14. Single chamber conveyor parts degreasing machine:
1 - pumping pumping unit; 2 - drain manifold; 3 - injection pumping unit; 4- washing chamber; 5 - settling tanks; 6 - plate conveyor
Equipment. The choice of equipment depends on the type of contamination of the parts, their size, detergents and the capacity of the repair company. For washing, degreasing and cleaning parts in the repair industry, the most widely used are conveyor-type jet washers, intermittent chamber washers, bathtubs and special installations (for cleaning parts from carbon deposits, scale, etc.).
Conveyor-type jet washers designed for washing units, assemblies and parts can be one-, two- and three-chamber. Single-chamber machines are intended for washing with water or degreasing with solutions that do not require subsequent rinsing with water. On 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 the 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 of the chambers, followed by hot water washing in the second.
Three-chamber machines have three washing zones. In the first zone, dirt is softened with a washing solution, in the second zone it is thoroughly washed and in the third zone it is rinsed with hot water. . It is economically feasible to use conveyor-type machines at large repair enterprises.
In intermittent chamber washing machines, parts are washed with a single solution, followed by rinsing with hot water. In the latter case, there are two baths: for washing solution and hot water. These machines are used in small repair enterprises and repair shops of operating farms.
Bathtubs are the simplest washing installations. Most often they are used for digestion of parts in alkaline or acid solutions. Bathtubs are made of steel; they consist of two compartments, one for washing solution, the other for water. The top of the bath is closed with a double-leaf lid.
Cleaning parts from soot. Details of soot can be cleaned by mechanical and physico-chemical methods.
Removal of carbon deposits mechanically 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 located in hard-to-reach places of the part. In addition, after the removal of soot on the smooth surfaces of parts, risks are formed, which during operation serve as centers of soot formation. Cleaning parts from carbon deposits with metal brushes and scrapers, due to its simplicity, has become widespread in the repair shops of road construction organizations. At large repair enterprises, cleaning of parts from soot with stone chips (crushed cherry and apricot pits) is widely used. This method is used to clean pistons, block heads, exhaust manifolds from carbon deposits. Its essence lies in the fact that crushed shells of fruit pits are fed to the part under air pressure of 0.4-0.5 MPa (4-5 kgf / cm2). Hitting the surface of the part, it cleans the deposit. On fig. 15 shows the design of the installation for cleaning parts with stone chips. Dry stone chips are poured into the tank through the door. Then it enters the bunker through the grid and the valve, and from there - into the mixer. The valve is opened at the right time with a lever. Air is supplied through the tube to the mixer, which carries the crumb into the sleeves to the tips. The amount of air entering the mixer is regulated by a valve, which is actuated by a pedal. The parts to be cleaned are placed on a rotating table. The worker, through the holes in the front door, inserts his hand into the protective sleeve and, taking the tip, directs a jet of stone chips onto the part, observing the cleaning process through the viewing glass.
Rice. 15. Installation for cleaning parts with stone chips
The working chamber is illuminated by a lamp. Dust crumbs and soot particles are sucked out through the pipe 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 tap is opened. This method is economical, productive and high-quality. For example, to clean a set of parts of one D-54A engine from carbon deposits, 4-5 kg of stone chips are consumed, which is 15-20 kopecks in monetary terms, the cleaning time is 30 minutes. Due to the fact that the crumb is deformed upon impact, there are no burrs and scratches on the cleaned surface of the part.
Small parts (valves, tappets, springs, etc.) are economically feasible to be chemically cleaned of carbon deposits. 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 washed in cold and hot water.
Rice. 16. Descaling unit:
1 - bath; 2 - cover; 3 - roller table; 4 - electric motor; 5 - special pump; 6 - electric heating device
Cleaning parts from scale. Cleaning of the water jacket of blocks and cylinder heads of engines is carried out at special installations. On fig. 16 shows an installation for descaling the block's water jacket. The block is installed on roller table 3 and with the help of a hose attached to the side flange of the block, a solution of trisodium phosphate heated to 60-80 ° C is pumped through its jacket at the rate of approximately 3-5 kg per 1 m3 of water. Can be used to remove scale and 8-10% hydrochloric acid solution. To protect the internal surfaces of parts from corrosion, 3-4 g of urotropine per 1 liter is added to the solution as an inhibitor. The solution is heated to 50-60 °C. The duration of washing, depending on the thickness of the scale layer, can be in the range of 10-70 minutes. After removing scale, the internal cavities of the parts must be rinsed with clean water.
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