Waterjet cleaning

Waterjet cleaning technology to quickly, efficiently and safely remove various types of pollution (corrosion, scale, rust, salt deposits, graffiti, etc.) from the surface of any shape without damaging the base material, while not causing harm to the environment.

Currently, there are quite a number of different technologies for treatment of surfaces. Each of them has certain advantages as well as disadvantages. In the application of many treatment technologies rather acute problem of ecology and recycling process emerging with the waste. Of existing modern methods: abrasive blasting, shot peening, ultrasonic cleaning, high pressure water, acid etching, - none of the above-mentioned no combines three main requirements - the environment, productivity and quality. Usually sacrificed the ecological balance between production activities and the environment.

Water jet cleaning technology has long been known, the first information about it appeared in the 60's of the last century, but for a long time, this method was not popular because it was hard to realize the process. Wide technology waterjet surface treatment received in the last two or three years. Currently, this technology is increasingly used in developed countries as well as in our own. The method is used where necessary to quickly and safely perform the work of cleaning and surface preparation.

 The essence of the method

Surface treatment of the air stream is filled with fine particles of water with abrasive is mixed with low pressure jets of pulp and high-pressure air stream accelerates the mixing chamber to speeds close to the sound. Feature of the technology of such processing is that with equal performance, higher quality cleaning of small value considerably reduces the burden for environmental protection. In addition, in terms of quality of machined surfaces, water jet cleaning has several advantages over other methods, because it allows you to remove dirt without disturbing the original surface, wash them out of the micropores and microcracks, the cleaning of thin sheets (0.3 mm) without warping , get to the roughness Ra 0,5 m, no sharzhirovaniya. The number of possible schemes and developed structures jet devices is large enough.

At present, the most widely used treatment waterjet machines are forced to pump slurry feed to the mixing chamber and its subsequent dispersal of compressed air. Such plants are stable in a wide range of pressure and flow suspension, providing enough performance and quality of treatment. In the process of development of technology waterjet machining conducted numerous studies on the material selection process fluid. Search criteria served as the best match the performance and quality of the process in compliance with hygiene standards.

Waterjet machining feature is the combination of the material removal process and the process of lubricating and cooling the treated surface. The working fluid slows somewhat abrasive, but it performs the following important functions: it provides transportation of abrasive particles from the storage container to the work surface, continuously cleans the surface, removing the spent abrasive particles and particles of your shot, eliminates dust, is the bearer of surfactants, creating absorbent layers of polar molecules and reduce the interatomic bonds in the surface layer of the material, thus reducing the hardness and fracture resistance of the material, regulates thermal conditions in the treatment area, prevents adhesion of the particles of the material removed to the treated surface and exhibits anti-corrosion properties.

Best result was obtained with the use of pomegranate concentrate, mineral abrasive, non-toxic material that does not contain silicon (ISO 11126-10 2000s), with a fraction of less than 0.1 mm, with a specific gravity of 4.1 t/m3, a Mohs hardness of 7 ,5-8, 0, grain shape is cubic, with sharp cutting edges, with a concentration in the suspension of about 20-30%. It was also found that the possible application of corundum, alumina, aluminum silicates, metal oxides, a saturated solution of soda ash. Studies and numerical simulations of the process impact of the drop and the solid particles were thoroughly conducted by American scientists (F Adler, A Ruff, C Viderhorn etc.). In the theoretical studies of erosion processes of liquid droplets and solid particles were determined speed and power characteristics, shape of the nozzle and calculated its basic parameters. This method allows you to replace outdated cleaning methods (abrasive, shot blasting, waterjet and mechanical) for a better and more eco-friendly, let you clean the surface of metals and non-metals from organic and inorganic contaminants, remove the cover, including layers, add new surface adhesion properties, producing decorative surface finishing products.

 Applications

These methods have been successfully applied in the engine-production, CHP power plant (gas turbine repair and steam engines, turbines, etc), shops of metallurgical plants (removal of scale from the surface of the semi-finished products of iron and non-ferrous metals), procurement workshops engineering plants (removal of oxide films, rust and etc. ) assembly plants (surface preparation prior to painting.) Applications waterjet cleaning: cleaning before painting, clearing suspensions in paint lines, cleaning stained defective parts from paint, cleaning molds motor drives, descaling metal sheets descaling titanium profile descaling round slab, cleaning of turbine blades, cleaning oil pollution from oil, cleaning all containers of various contaminants, cleaning welds, cleaning of any machine units, parts of industrial pollution, clearing of any metal, piping components, threads, surface preparation for welding, soldering, spray corrosion and other protective coating, cleaning pipes from the primer and protective coating, cleaning turbines, rotor blades, diaphragms, valves, piston housing, cleaning of wheel sets of railway wagons for fault detection, cleaning and rental of any casting, descaling after the heat treatment, the removal of oxide films discoloration and other contaminants, cleaning facades adjacent land and buildings of reinforced concrete structures, the dimensionless sand with finishing details, matte surface.

 Technological parameters

Abrasive (flow max b kg / sq m, the fraction of 20 -100 mm), compressed air (pressure of 7.6 atm, flow rate 4 cu m / min, the guild network or compressor), technical water (pressure 1,0-1, 5 atm, flow rate - 180 l / h 0 5 kW), the degree of surface cleaning - up to 100% Sa 3, roughness - the original (unchanged treated surface), not more than 062 mm.

 Summary

The advantages of the waterjet cleaning: conservation and roughness of the machined surface (from Ra 0,5 m), the lack of a controlled degree of hardening of machined surfaces can handle thin and delicate surfaces, the lack of removal of the base metal, the lack sharzhirovaniya, introduction of abrasive in the surface layer, the elimination of corrosion centers (for metals), the possibility of further inspection surface, the possibility of adding sequestering in the cleaning process to protect the cleaned surface of the secondary corrosion, environmentally friendly techniques (work in a closed loop), the abrasive garnet has a health certificate, no dust at work, compatibility with existing production processes, lack of need for water treatment, the use of free and low-cost raw materials, the use of abrasive repeatedly, resulting in lower cost of the process, fire, explosion.

 Restrictions on use

Ideal application of the method of waterjet cleaning - performance thin papers, where the highest class is important for cleaning up or getting the ideal surface with small roughness, without hardening, without inclusions, etc., but not appropriate for cleaning surfaces such as hull ships, which in the first place Cost performance index.

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