RU2450906C2 - Unit for aerohydrodynamic abrasive cleaning of surfaces, nozzle to this end (versions), and method of aerohydrodynamic abrasive cleaning of surfaces and composition to this effect - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to surface blasting, particularly, to aerohydrodynamic abrasive cleaning of surfaces, nozzle to this end, and method of aerohydrodynamic abrasive cleaning of surfaces and composition to this effect. Proposed unit comprises container with mixer to prepare abrasive suspension. Mixer comprises, at least, one vane. Nozzle serves to spray abrasive suspension and is communicated with aforesaid container and compressed gas feed device. Mixer comprises mixing blade arranged at container bottom. Besides, proposed unit comprises flushing fluid tank communicated with nozzle by air pump. Nozzle allows accelerating aerosol particles therein side upstream of nozzle outlet. Suspension contains clay loam and silica.

EFFECT: higher efficiency and reliability.

10 cl, 4 dwg

Description

The group of inventions relates to mechanical blasting of materials and can be used in various fields for cleaning any surfaces from organic and inorganic contaminants, removing coatings, including in layers, to give the surface new adhesive properties, to combine processing with passivation of the surface, for processing many types of parts with special requirements for fatigue strength and uncontrolled chemical processes during operation.

The invention can be used in the heavy and metallurgical industries, for example, in shops of metallurgical plants to remove scale from the surface of a semi-finished product from ferrous and non-ferrous metals, in the procurement shops of engineering plants to remove oxide films, rust, etc., for cleaning before painting, for preparing the surface for welding, soldering, applying anti-corrosion and other protective coatings, for dimensionless grinding during the finishing of parts, for cleaning bulk floors, etc. In the energy sector, the oil and gas complex and aviation, the invention can be used, for example, for cleaning and treating the blade apparatus of the rotor of turbines of thermal power plants, state district power plants, nuclear power plants (repair of gas turbine and steam engines, turbines, etc.), aircraft engines, cleaning and processing of the blade apparatus rotors of turbines of oil and gas pumping equipment, cleaning of pipeline elements, threads, decontamination of radioactive contaminants, etc. In transport and shipyards, the invention can be used to clean cars, including “graffiti”, to clean cars, wheelsets of railway cars for flaw detection, to process bodies and prepare parts for painting, to clean ship hulls, parts and equipment . In housing and communal services, construction and restoration, the invention can be used to clean various surfaces of facades from atmospheric, dirt, artificial pollution, biodegradants.

Closest to the proposed installation of aerohydrodynamic (AGD) abrasive surface cleaning, its nozzles and cleaning method are, respectively, the installation, nozzle and cleaning method known from SU 1740142 A1, publ. June 15, 1992 [1].

A known installation for aerohydrodynamic abrasive cleaning of surfaces includes a container for preparing an abrasive slurry with a stirring mechanism, including a stirrer with a blade, and a nozzle with an expanding nozzle for spraying an abrasive slurry, connected to the indicated container and to a compressed gas supply device.

A disadvantage of the known installation is the low cleaning quality when using mixtures having a relatively large and / or inhomogeneous fraction and forming a dense precipitate at the bottom of the tank.

The known nozzle for aerohydrodynamic abrasive cleaning of surfaces includes a hollow body with an expanding nozzle at the outlet, a compressed gas supply channel and a cleaning suspension supply channel connected to the body cavity.

A disadvantage of the known nozzle is the low cleaning efficiency due to the non-optimal combination of the speed of the jet of suspension, the concentration of abrasive particles in it, the shape and working area of the cleaning torch.

A known method of aerohydrodynamic abrasive cleaning of surfaces is that they act on the flow of the abrasive slurry with compressed gas to form aerosol particles and supply a stream of aerosol particles from the nozzle nozzle to the surface to be treated.

The disadvantage of this method is its low cleaning efficiency, due to the non-optimal combination of the speed of the jet of suspension, the concentration of abrasive particles in it, the shape and working area of the cleaning torch.

Closest to the proposed structure is a composition known from RU 2252084 C2, publ. 05/20/2005 [2].

The known composition for aerohydrodynamic abrasive cleaning of surfaces contains solid particles of aluminum oxide, silicon dioxide, calcium oxide, loam of various fractions.

A disadvantage of the known composition is the lack of cleaning efficiency due to the small particle size.

The technical result of the proposed group of inventions is to increase the productivity, efficiency and quality of cleaning by increasing the uniformity of the used fractions of the abrasive material and giving the jet a high speed suspension, a larger effective cleaning zone and an optimal distribution of abrasive particles and water in it.

The technical result is achieved by the fact that the installation for aerohydrodynamic abrasive cleaning of surfaces contains a container for preparing an abrasive slurry with a stirring mechanism, including a stirrer with at least one blade, and a nozzle for spraying an abrasive slurry connected to the indicated container and to a compressed gas supply device, while the mixer of the stirring mechanism includes a chopping knife mounted on it in the bottom of the tank, and the installation is equipped with a tank for washing fluid connected to the nozzle by means of an air pump.

In specific embodiments, the stirring mechanism may include a pneumatic motor coupled to the mixer connected to a compressed gas supply device through an air preparation unit including a desiccant and a lubricant supply device.

The mixing tank can be equipped with a hopper with a locking mechanism.

The air pump is preferably connected to an existing compressed gas supply device through an air preparation unit including a desiccant and a lubricant supply means.

Installation units can be connected via hoses with taps installed on them, while pressure sensors are installed on hoses connected to the nozzle.

The problem of the heterogeneity of the fractions was solved due to the structural element of the installation - a grinding knife, which gives the mass uniformity to obtain the AGD mixture, and also allows to grind a larger fraction to particle sizes from 100 μm to 300 μm, which are more efficient and show higher cleaning performance (m ² / hour).

The problem is also solved by the fact that, in one embodiment, the feature of the nozzle for aerohydrodynamic abrasive cleaning of surfaces, comprising a hollow body with an outlet nozzle, a compressed gas supply channel and a cleaning suspension supply channel connected to the body cavity, is that the nozzle is configured to be connected with a tank with flushing fluid by means of a pneumatic pump, the compressed air supply channel is connected to the cylindrical cavity of the body from the side opposite the nozzle, the nozzle is supplied with and a spray located in the body cavity in the form of a T-shaped nozzle, the crossbar of which is located along the axis of the housing, and the rack is connected to the feed channel of the cleaning suspension, the nozzle has a tapering part and a cylindrical part at the exit, and the spray outlet is located at a distance from the entrance to the cylindrical part of the nozzle with providing an acceleration zone for aerosol particles of the cleaning suspension.

The problem is also solved by the fact that in another embodiment, the feature of the nozzle for aerohydrodynamic abrasive cleaning of surfaces containing a hollow body with an outlet nozzle, a compressed gas supply channel and a cleaning suspension supply channel connected to the body cavity, is that the nozzle is adapted to a tank with flushing liquid by means of a pneumatic pump, the nozzle has a tapering part and a cylindrical part at the outlet, the outlet of the compressed gas supply channel is located on Normal distance from the entrance into the cylindrical part of the nozzle ensuring acceleration zones for cleaning particulate matter slurry, and the slurry supply port of the cleaning chamber in communication with the annular body, outlet openings which are arranged around the outlet of the compressed gas channel.

The problem is also solved by the fact that in the method of aerohydrodynamic abrasive cleaning of surfaces, which consists in exposing the abrasive suspension to a stream of compressed gas inside the nozzle with a tapering part and with a spray gun to form aerosol particles and supplying a stream of aerosol particles from the nozzle to the surface, a feature is that use a nozzle with a cylindrical part at the outlet, in which the outlet of the atomizer is located at a distance from the entrance to the cylindrical part of the nozzle, providing an acceleration zone for aerosol particles.

The problem is also solved by the fact that the composition for aerohydrodynamic abrasive cleaning of surfaces contains solid particles of loam and silica in the following ratio, wt.%:

loam 25-90 silica 10-75

Preferably, the solid particles of loam and silica have sizes from 100 μm to 1.8 mm.

The invention is illustrated using the drawings.

Fig. 1 schematically shows the proposed installation, Fig. 2 shows a first embodiment of a nozzle with through spraying using a T-shaped nozzle, Fig. 3 shows a second variant of a nozzle with an annular spray chamber having outlet openings around an air stream; 4 shows the connection diagram of the nodes of the proposed installation.

Installation for aerohydrodynamic abrasive cleaning of surfaces (see figures 1, 4) contains a container 1 for preparing an abrasive slurry with a stirring mechanism and a nozzle 2 for spraying an abrasive slurry connected to a tank 1 and to a compressed gas supply device 3.

The mixing mechanism includes a mixer 4 and a pneumatic motor 5 connected thereto, connected to a compressed gas supply device 3 through an air preparation unit 6, including a desiccant 7 and lubricant supply means 8. The mixer 4 is made with blades 9 and a chopping knife 10 mounted on it in the bottom of the tank 1.

The mixing tank 1 is equipped with a loading funnel 11 with a locking mechanism 12.

The installation is equipped with a tank 13 for flushing fluid connected to the nozzle 2 by means of a pneumatic pump 14 connected to the compressed gas supply device 3 through the air preparation unit 6.

The installation nodes are connected by means of hoses to the taps 15 installed on them, while on the hoses connected to the nozzle 2, pressure sensors 29 are installed. A pressure gauge 30 is installed on the hose connecting the air preparation unit 6 to the capacity 1.

In the upper part of the tank 1, a loading hole 31 is made and a fuse 32 to 6 atm is installed.

The nozzle 2 according to the first embodiment of the invention (see figure 2) contains a hollow body 16 with a nozzle 17 at the outlet. A channel 18 for supplying compressed gas and a channel 19 for supplying a cleaning suspension are connected to the cavity of the housing 1. The compressed air supply channel 18 is connected to the cylindrical cavity of the housing 1 from the side opposite to the nozzle 17. In the cavity of the housing 1 there is a spray in the form of a T-shaped pipe 20, the crossbar 21 of which is located along the axis of the housing, and the stand 22 is connected to the cleaning suspension supply channel 19 . The nozzle 17 has a tapering part 23 and at the exit a cylindrical part 24, while the nozzle outlet 25 is located at a distance from the entrance to the cylindrical part 24 of the nozzle 17, providing an acceleration zone for aerosol particles of the cleaning suspension.

The nozzle 2 according to the second embodiment of the invention (see figure 3) also contains a hollow body 16 with a nozzle 17 at the outlet. A channel 18 for supplying compressed gas in the form of a venturi and a channel 19 for supplying a cleaning suspension are connected to the cavity of the housing 1. The nozzle 17 has a tapering part 23 and a cylindrical part 24 at the exit. The outlet 26 of the compressed gas supply channel 18 is located at a distance from the entrance to the nozzle cylindrical part 24 to provide an acceleration zone for aerosol particles of the cleaning suspension. The cleaning suspension supply channel 19 is in communication with the annular chamber chamber 27, the outlet openings 28 of which are located around the outlet 26 of the compressed gas supply channel.

In both versions of the nozzles 2 there are pronounced zones of acceleration of air (zone A), while in the nozzle in figure 3 the acceleration zone is improved by using a venturi (cone). There is also a zone B - the acceleration zone of the air / cleaning mixture, in which air is mixed with the mixture in an enclosed space and the initial mixture is accelerated, and zone C is the zone in the nozzle 24 of the accelerator, in which the mixture is further accelerated, forming a working torch with larger area and increased cleaning efficiency.

Examples of mixtures of loams and silica dust used for cleaning:

PP-MT 30: 30% loam, 70% pulverized silica.

PP-MT 50: 50% loam, 50% pulverized silica.

PP-MT 70: 70% loam, 30% pulverized silica.

PP-MT 90: 90% loam, 10% pulverized silica.

Cleaning compositions are dispersions of loamy loam and special additives.

Loam in accordance with GOST - 28177-89 with a fraction of up to 40 microns, dust-like quartz in accordance with GOST - 9077-82 with a fraction of up to 40 microns can be used in these compositions.

However, it is more preferable to use fractions from 100 μm to 1.8 mm. The larger fraction is used to remove heavy contaminants such as corrosion and old paint and allows cleaning with a quality value of Sa2 according to ISO 8501-1. A smaller fraction (from 100 μm to 300 μm) is additionally crushed by mixing and allows the AGD cleaning and surface treatment, in which the chemical composition of the surface layer remains unchanged, which is an important factor for many types of parts with special requirements for fatigue strength and flow uncontrolled chemical processes during operation and allows to achieve Sa3 quality values according to ISO 8501-1.

The choice of the cleaning composition depends on the degree and type of contamination of the surface being cleaned, equipment, finishing materials, the condition of the facade, the presence of architectural details and is determined by the technology of work at a particular object.

A proportion of 6 liters of cleaning agent per 40 liters of water is sufficient to clean most contaminants. For the final washing of the facade surface from cleaning products, tap water is used.

The composition of the PP-MT 30 is used to clean heavy contaminants, remove stains from the surface, remove rust, scale, for example, to clean metal structures from aluminum alloys and other non-ferrous metals from atmospheric and other contaminants.

The composition of PP-MT 50 is used for cleaning medium pollution, layer-by-layer cleaning of stains, removing rust, moss, mold, carbon deposits, graffiti from facades, cleaning turbine rotors, and architectural monuments.

The composition of PP-MT 70 is used to clean light impurities, efflorescence, soil and atmospheric pollution.

The composition of PP-MT 90 is used to clean brittle surfaces from light impurities.

To prevent the occurrence of foci of biodestructive agents on facades and monuments, it is possible to use “cannon” lime according to GOST-9179-77 with a fraction of up to 100 microns as a cleaning composition.

The installation is as follows.

The unit can operate in the cleaning mode, in the washing / hydrophobization mode and in the drying mode. The nozzle operating modes are selected by opening or closing the corresponding taps 15 mounted on the nozzle 2, to which the nozzles are connected.

The unit must be operated at an ambient temperature of at least + 5 ° C.

Depending on the type and degree of contamination, the distance from the object being cleaned to the outlet of the nozzle 24 should be 50 ... 180 mm. In the process, the axis of the nozzle should be located at an angle of 60 ... 80 degrees to the machined surface of the facade.

When working with the installation, the actions are performed in the following sequence:

- check the absence of gaps in the transport systems of air supply and composition;

- connect the air supply hoses to the compressor and check the reliability of the connection and the absence of kinks in the air and suspension hoses;

- fill the tank 1 with the finished composition or prepare the composition directly in the tank 1 for which pour tap water into it and add the solid component in the required concentration;

- include a mechanism for mixing the composition to ensure preliminary mixing of the composition for at least 10 seconds;

- include the supply of air and slurry to the respective transport lines with reliable holding in the hands of the nozzle 2 and the direction of the nozzle 24 towards the surface to be cleaned.

In the cleaning mode, air under pressure from 4 to 12 atm enters the air supply device 3, in which the distribution through the systems takes place. In the desiccant 7 of the air preparation unit 6, it is drained and lubricated by means of a lubricant supply means 8.

From block 6, air through a tap / regulator enters a pneumatic motor 5, which transmits rotation to a mixer 4 with blades 9 and a chopping knife 10, due to which mixing of a mixture of water and a cleaning composition or grinding of a dry cleaning composition such as soda in a container 1 is performed. When the pulp is mixed, dense layers are deposited at the bottom of the tank 1. The sediment interferes with the passage of pulp into the channel 19. The knife 10 is designed to loosen the sediment at the bottom of the tank 1 and prevent its formation.

From block 6, air is also supplied to a container 1 for preparing an abrasive slurry to create a pressure of 1-1.5 atm in it, which is necessary for the formation of the mixture and its transportation through the hose to the nozzle 2.

When mixed with water in the above proportions of PP-MT cleaning composition, an abrasive slurry is formed under a pressure of 1-1.5 atm, which is necessary for the manifestation of the properties of AGD cleaning and the creation of the Rebinder effect.

The suspension from the tank 1 is fed through the channel 19 to the pipe 20 or to the annular chamber 27, at the outlet of which it is mixed with a high-pressure stream of air entering the channel 18 from the device 3, and acquires acceleration. Next, the mixture of air and suspension is accelerated to high speeds. Under the action of the jet, a so-called hydroabrasive aerosol is formed, consisting of abrasive particles, air and liquid. The hydroabrasive spray obtained in this way cleans surfaces. The energy carrier of aerosol particles in the AGD method is a high-speed (more than 500 m / s) air stream. Aerosol particles are water molecules concentrated in droplets under high pressure (about 1 atm), inside of which are solid particles (abrasive dust) ranging in size from 300 nm to 40 microns. Hitting the surface, water in contact, due to the manifestation of the Rebinder effect, reduces the strength of the surface being treated, after which the abrasive particle mechanically destroys the contamination and the water washes out the split fragments and carries them along with the used abrasive.

The working fluid provides transportation of abrasive particles from the supply tank to the surface to be treated, continuously cleans the surface to be treated, removing spent abrasive particles and particles of removed material, eliminates dust formation, regulates the thermal regime in the treatment zone, allows collecting waste from cleaning and reusing the working mixture.

In the washing / hydrophobization mode, the pneumatic pump 14, also working from the air coming from the device 3, provides for the transfer of water or a hydrophobizer from the tank 13 for the flushing liquid through the hose to the nozzle 2.

The drying mode is achieved by closing two taps 15 on the hoses connected to containers 1, 13 and opening the faucet 15 of the hose connected to the air supply device 3. The surface air is dried from the nozzle 2.

When interacting with the surface, the proposed processing method does not adversely affect the parameters of the initial metal surface, which compares it favorably with other methods of cleaning and decontamination. After processing, the physicochemical composition of the surface layer of the metal remains unchanged, which is an important factor for many types of parts with special requirements for fatigue strength and uncontrolled chemical processes during operation. Also, when using the proposed method, the adhesive properties of the metal are improved, which is due to a decrease in surface water absorption after processing.

Claims (10)

1. Installation for aerohydrodynamic abrasive cleaning of surfaces, containing a container for preparing an abrasive slurry with a stirring mechanism, comprising a mixer with at least one blade, and a nozzle for spraying an abrasive slurry connected to the indicated container and to a compressed gas supply device, characterized in that the mixer of the stirring mechanism includes a chopping knife mounted on it in the bottom of the tank, and the installation is equipped with a tank for flushing fluid connected to a sucker by means of an air pump. 2. Installation according to claim 1, characterized in that the stirring mechanism includes a pneumatic motor connected to the mixer connected to a compressed gas supply device through an air preparation unit, including a desiccant and a lubricant supply device. 3. Installation according to claim 1, characterized in that the mixing tank is equipped with a loading funnel with a locking mechanism. 4. Installation according to claim 2, characterized in that the pneumatic pump is connected to a compressed gas supply device through an air preparation unit, including a desiccant and a lubricant supply means. 5. Installation according to claim 1, characterized in that its nodes are connected by means of hoses with taps installed on them, while pressure sensors are installed on hoses connected to the nozzle. 6. Nozzle for aerohydrodynamic abrasive cleaning of surfaces, comprising a hollow body with an outlet nozzle, a compressed gas supply channel and a cleaning suspension supply channel connected to the body cavity, characterized in that it is adapted to be connected to the container with the washing liquid by means of a pneumatic pump, channel compressed air supply is connected to the cylindrical cavity of the housing from the side opposite the nozzle, the nozzle is equipped with a spray located in the cavity of the housing in the form of a T-shaped nozzle, the crossbar of which is located along the axis of the casing, and the rack is connected to the feed channel of the cleaning suspension, the nozzle has a tapering part and a cylindrical part at the exit, and the nozzle outlet is located at a distance from the entrance to the cylindrical part of the nozzle, providing an acceleration zone for aerosol particles of the cleaning suspension. 7. Nozzle for aerohydrodynamic abrasive cleaning of surfaces, comprising a hollow body with an outlet nozzle, a compressed gas supply channel and a cleaning suspension supply channel connected to the body cavity, characterized in that it is adapted to be connected to the container with a washing liquid by means of a pneumatic pump, a nozzle has a tapering part and a cylindrical part at the outlet, the outlet of the compressed gas supply channel is located at a distance from the entrance to the cylindrical part of the nozzle, providing an for aerosol particles of the cleaning suspension, and the supply channel of the cleaning suspension is in communication with the annular chamber chamber, the outlet openings of which are located around the outlet of the compressed gas supply channel. 8. The method of aerohydrodynamic abrasive cleaning of surfaces, which consists in the fact that inside the nozzle with a tapering part and with a spray gun, they act on the flow of the abrasive suspension with compressed gas to form aerosol particles and a stream of aerosol particles from the nozzle is fed to the surface, characterized in that they use a nozzle with a cylindrical part at the outlet, in which the outlet of the atomizer is located at a distance from the entrance to the cylindrical part of the nozzle with providing an acceleration zone for aerosol particles. 9. The composition for aerohydrodynamic abrasive cleaning of surfaces, containing solid particles of loam and silica, characterized in that the loam and silica have the following ratio, wt.%:
loam 25-90 silica 10-75 10. The composition according to claim 9, characterized in that the solid particles of loam and silica have sizes from 100 μm to 1.8 mm

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