Comprehensive cryo jet cleaning system for surfaces with modular co2 granule dispenser and controlled continuous-pulse modes and cryo jet cleaning method

Abstract

FIELD: cryo-jet cleaning system for surfaces.SUBSTANCE: system which contains a thermally insulated bin for carbon dioxide granules, a dispenser for introducing granules into a compressed gas flow, a pneumatic line, a manual gun-manipulator with replaceable nozzles, a pneumatic preparation unit with gas drying and filtration, a receiver and pressure regulator, and an electronic control system. The electronic control system is designed with the ability to set the flow rate of granules, pressure and / or flow rate of compressed gas and select the mode of continuous or pulsed supply of the cleaning jet with the setting of programmable frequency and duty cycle profiles. The dispenser is designed as a modular unit with the possibility of implementing at least one of the following dosing mechanisms: auger, disk, shaft or pneumatic.EFFECT: gentle and environmentally friendly cleaning without abrasive wear of the base and without secondary waste.36 cl, 5 dwg, 2 ex

Description

[0001] Technical field

[0002] The invention relates to the field of cleaning and processing surfaces, in particular to cryojet technologies using carbon dioxide (CO2) granules to remove contaminants, coatings and technological deposits, and can be used in mechanical engineering, the aerospace industry, energy, medicine, food and electronics industries.

[0003] Technology Level

[0004] Currently, various cryogenic (dry ice) blast cleaning devices are widely used. These units use solid carbon dioxide (CO2) granules as the working fluid. The operating principle is based on the impact of granules accelerated by compressed air on the contaminated surface. Cleaning is achieved through three factors: the low temperature of the granules (approximately -78.5°C), their kinetic impact, and instantaneous sublimation with a sharp increase in volume, creating a micro-explosive effect. Cryogenic blast cleaning technology is used in mechanical engineering, aircraft manufacturing, energy, food, and electronics industries due to its environmental friendliness, lack of abrasive wear on the substrate, and the absence of secondary waste.

[0005] The closest analogue to the present solution is a device for feeding solid cryogenic granules into a compressed air stream, described in RU 2748313 C1, published April 25, 2021. The device comprises a granule hopper, a feed unit with a portioning shaft and seal, and a path for aerodynamic "washing" of the granules. This solution delivers granules into the air stream, but focuses primarily on the design of the feed unit and its sealing elements. The disadvantages of this known device include:

[0006] - lack of controlled operating modes (continuous and pulsed);

[0007] - limited variability of dispensers (only the gross type is disclosed);

[0008] - lack of integration with the process parameter control system (granule consumption, air pressure / flow, mode selection);

[0009] - lack of thermal insulation of the hopper, built-in pneumatic preparation and a standard set of replaceable nozzles;

[0010] - lack of noise reduction and convenient readjustment to different working conditions.

[0011] Thus, the known device provides only a basic supply of CO2 granules, but does not solve the problem of creating a universal and customizable cryo-jet cleaning system with an extended range of modes, stable supply of granules and increased operational reliability.

[0012] Problem and technical result

[0013] The objective of the present invention is to create a comprehensive cryo-blasting surface cleaning system that ensures process versatility and customizability due to an extended range of granule feed modes (continuous and pulsed); stable dry ice feed under various operating conditions; and the ability to quickly adapt to the type of surface and contamination (nozzle selection, mode, flow rate).

[0014] The technical result achieved by implementing the claimed solution consists in increasing the efficiency and quality of cryo-blasting cleaning by simultaneously ensuring delicate removal of contaminants without abrasive wear of the base and without secondary solid or liquid waste, reducing the consumption of dry ice thanks to pulse modes and built-in pneumatic preparation, increasing the stability of the granule supply due to thermal insulation of the hopper and a built-in air drying system, flexible adjustment of process parameters (granule mass flow rate, air pressure / flow rate, supply mode) for a specific material and type of contaminant.

[0015] An additional technical result consists of increasing the ease of operation and safety of the installation due to the modular design of the dispensers, the presence of a standard set of replaceable nozzles, noise protection equipment, as well as an integrated electronic control system with the ability to save operating profiles.

[0016] Disclosure of the essence of the invention

[0017] The stated problem is solved, and the required technical result is achieved through the use of a cryo-jet cleaning system for surfaces, containing a thermally insulated bin for carbon dioxide granules, a dispenser for introducing granules into a compressed gas flow, a pneumatic line and a manual gun-manipulator with replaceable nozzles, characterized in that the system is equipped with a pneumatic preparation unit with air drying and filtration, a receiver and a pressure regulator, wherein the dispenser is made modular with the possibility of implementing at least one of the dosing mechanisms: screw, disk, shaft or pneumatic, and the system is equipped with an electronic control system configured to set the flow rate of granules, pressure and / or flow rate of compressed air and select a continuous or pulsed supply mode, including programmable frequency and duty cycle profiles.

[0018] The pneumatic preparation unit contains a refrigeration dryer and a fine coalescent filter.

[0019] The pulse mode is formed by a regulating / pulse valve in the air duct with synchronization of the dispenser operation.

[0020] The system is available in mobile or stationary versions.

[0021] Moreover, in a mobile version it contains a frame / chassis with a compressor, receiver and control system.

[0022] At the same time, the gun-manipulator is designed with an interface for quickly changing nozzles of various geometries, including straight, expanding and angular.

[0023] In this case, the compressed gas source is built-in (compressor on the frame) and / or external (main gas), with automatic source switching.

[0024] In this case, air, nitrogen and / or inert gas are used as compressed gas.

[0025] The pneumatic preparation unit additionally contains an adsorption dryer with automatic drainage.

[0026] Moreover, the hopper is equipped with a vibration activator and / or anti-friction inserts to prevent granules from caking.

[0027] In addition, the pneumatic line contains quick-release couplings and / or rotary couplings for quick changeover.

[0028] The dispenser module is designed to be quickly removable with a unified connection interface for interchangeable installation of auger, disc, shaft or pneumatic mechanisms.

[0029] In turn, the granule consumption is controlled by signals from the position / speed sensor of the dispenser drive and / or the hopper weight sensor with the calculation of the mass flow rate.

[0030] Moreover, the mixing zone is made with rounded joints and an anti-adhesive coating, eliminating dead zones and granule sticking.

[0031] In addition, the gun-manipulator is equipped with a “safety button” and a start lock in the absence of pressure / flow.

[0032] Moreover, the nozzle mounting interface is variable and is made with a quick-change bayonet / " / 4-turn with keyway positioning.

[0033] In addition, the nozzles are made of wear-resistant polymer / composite and / or metal with a hardening coating, with straightening inserts and radius channel connections.

[0034] The corner nozzle is made rotatable with a flow deflection angle in the range of 30-120°.

[0035] In addition, the system additionally contains a slot nozzle for forming a flat jet when processing areas.

[0036] The electronic control system implements closed loops for pressure and / or flow with digital filtering of measurements, limiting the rate of signal change and integrator protection.

[0037] In turn, the pulse mode is formed by a valve with frequency control in the range of at least 0.5-30 Hz and a duty cycle of 10-90% with synchronization of the supply of granules by the dispenser.

[0038] The system contains recipes / mode profiles with a set of settings (material type, pressure / flow rate, frequency and duty cycle) selected from the operator panel.

[0039] The system is also equipped with gas flow, pressure and temperature sensors with parameter indication and event logging (starts, accidents, deviations).

[0040] In addition, the system is housed in a noise-absorbing casing with ventilation and / or thermal screens.

[0041] The system also includes a remote interface (wired and / or wireless) for monitoring and updating profiles.

[0042] The system also contains at least two manipulator guns with flow switching or parallel operation.

[0043] In addition, the system is equipped with a bypass purge line to clean the lines from condensate and particles.

[0044] In this case, the working pressure of the compressed gas at the inlet of the dispenser is 0.4-1.8 MPa.

[0045] The jet speed at the nozzle outlet is 100-300 m / s.

[0046] The size of CO2 granules is in the range of 0.5-5mm in equivalent diameter.

[0047] The stated problem is solved, and the required technical result is achieved by implementing a method for cryo-jet cleaning of surfaces, implemented using a system that includes feeding carbon dioxide granules from a thermally insulated bin into a compressed air stream, transporting the mixture through a pneumatic line and ejecting it through a nozzle onto the surface being treated, wherein at least one parameter from the group is set by means of an electronic control system: mass flow rate of granules, pressure and / or air flow rate, continuous / pulsed feed mode, wherein in the pulsed mode a programmable profile is formed with specified frequency and duty cycle for adaptation to the type of material and contamination, ensuring the combined action of cryogenic cooling, kinetic impulse and sublimation expansion of CO2.

[0048] In this case, the pulse mode profile is selected from among pre-saved recipes for typical materials / contaminants.

[0049] In this case, in the pulse mode, the valve opening frequency is selected within the range of 0.5-30 Hz, and the duty cycle is 10-90%.

[0050] Before feeding the mixture, the air is dried and filtered to a specified dew point to prevent freezing.

[0051] For delicate surfaces, use a diffuser or slot nozzle, and for hard-to-reach areas, use an angle nozzle.

[0052] At the same time, the pressure and / or gas flow are monitored in closed loop mode and when the parameters go beyond the set limits, the system is transferred to a safe mode.

[0053] Brief description of drawings

[0054] The essence of the claimed invention is explained by drawings, which indicate the following positions:

[0055] 1 - Frame / chassis of mobile unit

[0056] 2 - Insulated CO2 Pellet Hopper

[0057] 3 - Dispenser / mixing chamber

[0058] 4 - Manipulator Pistol

[0059] 5 - Straight nozzle (replaceable)

[0060] 6 - Diffuser nozzle (expanding)

[0061] 7 - Angle nozzle (replaceable)

[0062] 8 - Pneumatic line

[0063] 9 - Pneumatic preparation unit (assembly unit, see positions 10-22)

[0064] 10 - Compressor motor

[0065] 11 - Viscous coupling

[0066] 12 - Compressor screw pair

[0067] 13 - Air filter (intake)

[0068] 14 - Separator tank (oil separation)

[0069] 15 - Oil filter

[0070] 16 - Radiator-cooler

[0071] 17 - Receiver

[0072] 18 - Safety valve on the receiver

[0073] 19 - Drain valve / condensate drain on the receiver

[0074] 20 - Refrigerated Dryer

[0075] 21 - Moisture and oil filter (fine cleaning)

[0076] 22 - Pressure regulator (reducer / proportional)

[0077] 23 - Air flow sensor

[0078] 24 - Control and regulation system

[0079] 25 - Operator Panel (HMI)

[0080] 26 - Air supply control / pulse valve

[0081] 27 - Temperature sensor

[0082] 28 - Pressure sensor

[0083] 29 - Controller / PLC (control unit)

[0084] Fig. 1 shows a general view of the mobile installation;

[0085] Fig. 2 shows the structural diagram of the system;

[0086] Fig. 3 shows the pneumatic preparation unit;

[0087] Fig. 4 shows the control system;

[0088] Fig. 5a, 6, c, g show a gun-manipulator and a set of nozzles (straight, expanding, angular) + schematic profiles of the gun-manipulator jet.

[0089] Implementation of the invention

[0090] The operating principle of the claimed system is based on the use of solid carbon dioxide (dry ice) granules accelerated by a compressed air flow to high speeds (150-300 m / s) and directed through a nozzle onto the surface being cleaned. Cleaning is achieved through the combined action of three physical factors:

[0091] - cryogenic cooling (-78.5°C), causing embrittlement and cracking of contamination;

[0092] - sublimation expansion: granules instantly turn into gas with an increase in volume by 700 - 800 times, creating a local pressure pulse (“microexplosion”);

[0093] - kinetic impact, mechanically destroying the weakened layer of contamination.

[0094] Dry ice pellets completely sublime, leaving no solid or liquid waste; the removed contaminant particles are carried away by the air flow.

[0095] Below are the physical and technical principles of the process and the engineering relationships that justify the operating modes and units used in the present invention.

[0096] Let's calculate CO2 sublimation and refrigeration balance.

[0097] The specific heat of sublimation (at ~1 atm) is calculated using the formula

[0098] ΔH sub ≈5.7×10 2 kJ / kg. (1)

[0099] The refrigeration flow is calculated using the formula

[0100]

[0101] where - mass flow rate of dry ice granules, kg / s,

[0102] ΔH sub - specific heat of sublimation, J / kg,

[0103] - cooling capacity (heat flow), W.

[0104] Volume of CO2 gas from 1 kg of dry ice (under normal conditions):

[0105] Vg≈0.53-0.56 m 3 / kg, (3)

[0106] which corresponds to an increase in volume of 700-800 times compared to the solid phase.

[0107] The jet dynamics calculation is carried out as follows.

[0108] Dynamic pressure is determined by the formula

[0109]

[0110] where q is the dynamic pressure, Pa;

[0111] ρ - air density, kg / m3 3 ;

[0112] V - air / mixture flow velocity, m / s.

[0113] The flow momentum is calculated from the expression

[0114] J= *V, (5)

[0115] where J is the axial momentum of the flow, N;

[0116] - mass flow rate of the mixture, kg / s.

[0117] The jet power is calculated by the formula

[0118]

[0119] where R струи - flow power, W;

[0120] A с - nozzle outlet cross-section area, m 2 .

[0121] When designing system components, heat exchange and thermal shock processes occurring when dry ice granules come into contact with the surface being treated are taken into account. The heat flux density in the impingement zone can be estimated using the expression

[0122] =h * (T пов -T гран ), (7)

[0123] where - heat flux density, W / m 2 ;

[0124] h - heat transfer coefficient at impingement, W / (m 2 ⋅K);

[0125] T пов - surface temperature before treatment, °C or K;

[0126] T гран - granule temperature, °C or K.

[0127] The resulting sharp cooling of the contaminated layer leads to the development of thermoelastic stresses, the magnitude of which can be estimated using the formula:

[0128] σ терм =E*(α f - α s )*ΔT, (8)

[0129] where σ терм - stress in the coating, Pa;

[0130] E - modulus of elasticity of the coating material, Pa;

[0131] α f and α s - coefficients of linear thermal expansion of the coating and base, 1 / K;

[0132] ΔT - temperature difference, K.

[0133] To achieve optimal cleaning results, it's important to select not only nozzle geometry and air pressure, but also the CO2 granule delivery mode. A controlled pulse mode allows for alternating intense and paused phases, enhancing the thermal shock and mechanical impact while simultaneously reducing the average ice and air consumption. The average flow characteristics at duty cycle D are described by the relationship:

[0134]

[0135] where - average mass flow rate of granules, kg / s;

[0136] - mass flow rate in open phase, kg / s;

[0137] D - duty cycle (fraction of valve open state, 0-1).

[0138] The maximum operating pulse frequency is limited by the system response time, which includes the hydrodynamic relaxation of the jet and the thermal response of the contamination:

[0139]

[0140] where f is the pulse frequency, Hz;

[0141] τ гидр - characteristic hydrodynamic time of jet acceleration / attenuation, s;

[0142] τ тепл - characteristic thermal time of cooling / heating of pollution, sec.

[0143] Thus, the choice of pulse frequency and duty cycle sets a compromise between cleaning efficiency and the cost-effectiveness of granule consumption.

[0144] To ensure the specified ice mass flow rate, the system uses a modular dispenser. Its characteristics depend on the operating principle.

[0145] So, for the auger design, they rely on the expression

[0146] =ρ насып *A кан *s*n, (11)

[0147] where ρ насып - bulk density of granules, kg / m3 3 ;

[0148] A кан - cross-sectional area of ​​the auger channel, m 2 ;

[0149] s - auger pitch, m;

[0150] n - rotation speed, rpm.

[0151] In turn, for a disk or shaft design, the calculation of the dispenser is carried out on the basis of the formula

[0152] = ρ насып *V карм *ƒ карм , (12)

[0153] where V карм - volume of one pocket, m 3 ;

[0154] ƒ карм - frequency of pocket emptying, 1 / s.

[0155] Finally, when designing the installation, it is important to correlate the thermal load on the surface being treated with the granule feed capacity. For a surface area of ​​area A and the required reduction in fouling temperature ΔT z the required heat flux is defined as:

[0156] ≈A*h*ΔT z , (13)

[0157] where - required heat flow, W;

[0158] h - heat transfer coefficient, W / (m2 ⋅K);

[0159] ΔT z - required temperature reduction, K.

[0160] The required mass flow rate of ice to implement this cooling is estimated by the expression:

[0161]

[0162] where ΔH sub - specific heat of sublimation of CO2, J / kg.

[0163] From the given physical relationships it follows that the efficiency of cryo-jet cleaning is determined by:

[0164] 1) ensuring the required mass flow rate of granules (formulas (2), (11), (12));

[0165] 2) the ability to regulate the speed and impulse of the jet v, J, P струи (formulas (4)-(6));

[0166] 3) stability of heat exchange and the magnitude of thermoelastic stresses σ терм (formulas (7), (8));

[0167] 4) optimal choice of frequency and pulse duty cycle ƒ, D (formulas (9), (10)).

[0168] To implement these requirements, the following units are provided in the claimed system (see Fig. 1-5):

[0169] 1. Thermally insulated bin that ensures stable ice supply and minimizes sublimation losses, which is critical to maintaining the calculated mass flow rate. .

[0170] 2. Modular dispenser (auger, disc, shaft or pneumatic), which allows you to set the flow rate according to formulas (11), (12) and adapt the feed mode to the type of surface and contamination.

[0171] 3. Pneumatic preparation (dryer, filters, receiver), which ensures the purity and stability of the air flow, which is necessary for the reproducibility of the speeds v and pressure q.

[0172] 4. Pneumatic line and gun with a set of replaceable nozzles that form a jet with a given cross-section Ac and speed v, realizing the calculated impulses and powers (formulas (4)-(6)).

[0173] 5. Electronic control system that implements a pulse mode with adjustable duty cycle D and frequency ƒ (formulas (9), (10)), which allows alternating phases of intense exposure and pauses.

[0174] Thus, each structural unit of the system directly corresponds to the physical parameters of the process and allows them to be controlled within the operating range, ensuring the achievement of the technical result: gentle and effective cleaning without abrasive wear of the base and without secondary waste.

[0175] Below is an analysis of the claimed design.

[0176] In general, the claimed complex cryojet cleaning system can be implemented in a stationary design or as a mobile unit.

[0177] In the mobile version, the cryo-jet cleaning system is made on a frame (1) mounted on wheels or supports for ease of movement, as shown in Fig. 1.

[0178] The upper part of the frame (1) houses a thermally insulated bin (2) for storing dry ice pellets. The bin is equipped with a lid and a thermal insulation layer to prevent premature sublimation of the pellets and ensure a stable supply of material.

[0179] At the bottom, the hopper (2) is connected to the dispenser (3), a modular unit that allows for the installation of a screw, disc, shaft, or pneumatic feed mechanism, depending on the required operating mode. From the dispenser, the granules enter the pneumatic line (8), which is connected to the compressed air system. For this purpose, a motor (10) is mounted on the frame and is kinematically linked to a compressor, which supplies air to the line (8).

[0180] On the side panel of the frame there is a control and regulation system (24), including an electronic controller (29), an operator interface (25) and connections to pressure sensors (28), temperature (27) and air flow (23), ensuring automatic maintenance of process parameters.

[0181] The flow of cryogenic mixture from the dispenser (3) is fed through the line (8) to the gun-manipulator (4) (see Fig. 5 a, b, c, d), from the nozzle (5), (6), (7) of which dry ice granules are directed at high speed onto the surface being cleaned.

[0182] Thus, all the main components - the hopper (2), the dispenser (3), the control system (24), the engine (10) and the pneumatic line (8) - are mounted in a single frame body (1), ensuring compactness, mobility and ease of maintenance of the unit.

[0183] Fig. 2 schematically shows the functional connections of the nodes of the complex system.

[0184] Compressed air tract.

[0185] Compressed air is generated by the compressor module, the drive of which is designated by the motor (10), then enters the receiver (17) for accumulation and smoothing of pressure pulsations. From the receiver, the flow is directed to the pneumatic preparation unit (9), where it undergoes pressure regulation (22), drying and filtration (for unit details, see Fig. 3). The prepared air is supplied via the pneumatic line (8) to the regulating / pulse valve (26), which, upon commands from the control system, ensures continuous or pulsed supply to the dispenser / mixing chamber (3). From the dispenser (3), the air-cryogenic mixture is transported to the manipulator gun (4).

[0186] CO2 Granule Path.

[0187] Dry ice granules flow by gravity from a heat-insulated bin (2) into a dispenser (3), where they are dosed into the air flow, accelerated and then directed through a line to a gun-manipulator (4) for ejection through a selected nozzle (see Fig. 5 6, c, d, positions 5-7).

[0188] Control and monitoring circuit.

[0189] The operation of the units is coordinated by the control and regulation system (24), including the operator panel (25) and the controller / PLC (29). The controller receives signals from the air flow sensor (23), temperature sensor (27), and pressure sensor (28) and generates control actions for the valve (26) and dispenser (3) to maintain the specified process parameters, including the implementation of the pulse mode (duty cycle and frequency).

[0190] Now let us turn to Fig. 3 - the pneumatic preparation unit (details of unit 9).

[0191] The pneumatic preparation unit (9) generates a compressed air flow with a stable pressure, flow rate, and humidity level for delivery to the dispenser (3). Fig. 3 shows the sequence of units along the flow path and their functions.

[0192] Composition and operation of the unit (in the direction of flow).

[0193] Compressor module.

[0194] The compressor motor (10) drives the compressor unit. The viscous coupling (11) provides damping of starting / shock torques and protects the shaft group. The compressor screw pair (12) compresses the air to the required pressure. The air filter (13) (suction) traps dust and aerosols at the inlet, reducing wear. The compressor outlet contains oil aerosol and superheated air.

[0195] Primary separation and purification. The separator tank (14) separates oil mist and condensate from the compressed air; the oil is returned to the compressor's oil circuit. The oil filter (15) further cleans the flow of residual oil / particles after separator 14.

[0196] Cooling and accumulation. The radiator-cooler (16) reduces the temperature of the compressed air, increasing the efficiency of subsequent drying. The receiver (17) accumulates compressed air, smooths out pulsations, and serves as a buffer during the pulse operation of the valve (26).

[0197] The receiver is equipped with: a safety valve (18) for pressure protection and a drain valve / condensate drain (19) for periodic removal of condensate.

[0198] Drying and fine filtration. The refrigerated dryer (20) lowers the dew point, preventing condensation and freezing in the dispenser (3) and pneumatic line (8). The moisture and oil filter (21) (coalescing / fine filter) removes residual aerosols and fine impurities, ensuring clean air at the process inlet.

[0199] Regulation and control. The pressure regulator (22) (reducer / proportional) sets the operating pressure for section 8→26→3, ensuring reproducible jet velocity and correct operation of the dispenser. The air flow sensor (23) measures the current volumetric / mass flow; its signal is sent to the controller (29) of the system (24) (see Fig. 4) for closed-loop control of modes, including pulsed.

[0200] Functional features.

[0201] The combination of the radiator, refrigeration dryer, and fine filter ensures a low dew point and minimal residual oil content, preventing freezing and sticking of CO2 granules in the mixing zone. The receiver, in turn, improves pressure stability when switching valve 26 in pulse mode and reduces the load on the compressor module. The pressure regulator sets the operating pressure in the process circuit, independent of fluctuations on the compressor side. Air flow sensor 23 measures the flow rate to maintain target parameters. and calculation of pulse profiles (see Fig. 4).

[0202] Maintenance and safety are ensured by monitoring and periodically replacing filter elements (13, 15, 21) based on pressure drop / regulations. Condensate is also regularly removed through the drain valve (19) and the operation of the safety valve (18) is checked.

[0203] Thus, the pneumatic preparation unit (9) ensures stable and reproducible air flow parameters (pressure, flow rate, temperature and humidity) necessary for the correct operation of the dispenser (3) and the formation of a cryojet at the outlet of the manipulator gun (4), including in controlled continuous-pulse modes (see Fig. 2 and Fig. 4).

[0204] Let us refer to Fig. 4, which shows the control and regulation system (24).

[0205] The specified unit (24) provides setting, maintenance and switching of the cryo-jet cleaning system, including continuous and pulse modes, as well as control of air flow parameters and the state of the dispenser (3).

[0206] The operator panel (25) is an HMI interface for setting the setpoints (pressure, pulse profile: frequency / duty cycle, target air flow, granule flow), calling up recipes and displaying current parameters / alarms.

[0207] The controller / PLC control unit (29) is the central unit for processing signals and generating control actions; it is connected to the power and pneumatic elements and receives signals from the sensors.

[0208] The air flow sensor (23) is installed in the pneumatic tract on the side of the pneumatic preparation unit (9) and transmits the measured value to the controller (29). for closed-loop control.

[0209] The temperature sensor (27) monitors the air temperature (and / or in the mixer area / pneumatic line (8)) to prevent freezing and going beyond the permissible conditions.

[0210] The pressure sensor (28) monitors the working pressure in the feed section to the dispenser (3).

[0211] The air supply control / pulse valve (26) is an actuator on the line (8) that generates a continuous supply or pulse modulation according to the commands of the controller (29).

[0212] The dispenser / mixing chamber (3) receives control signals (start / stop, speed profiles, pulse synchronization enable).

[0213] The principle of the system.

[0214] The operator sets the setpoints (pressure, target air flow, continuous / pulse mode, pulse frequency / duty cycle, recipes) on the operator panel (25). The controller (29) reads the measurements from sensors (23), (27), (28) in real time, compares them with the setpoints, and controls the air supply valve (26) and the dispenser (3).

[0215] In continuous mode, a stable flow / pressure is maintained at the dispenser inlet with correction by sensors (23) and (28).

[0216] In pulse mode, the controller (29) generates the specified frequency ƒ and duty cycle D of the valve (26) opening, optionally synchronizing the time profiles of the granule feed in (3) to maintain the target average flow rate and increase the peak effect of the jet.

[0217] When the temperature limit / alarm values ​​in the temperature sensor (27) or the pressure in the pressure sensor (28) are reached, the controller (29) switches the system to a safe mode: limiting the opening of the valve (26), stopping the dispenser (3), warning / alarm indication on the operator panel (25).

[0218] The system implements two closed loops (flow rate via sensor 23 and pressure via sensor 28) with measurement filtering, PID / PI control, rate of change limitation, dead zone, cascade coordination (priority to pressure loop) and safe switching of valve 26 / stopping of dispenser 3 when parameters go beyond the limits.

[0219] Setting the pulse profile ƒ (Hz) and D (0-1) to ensure acceptable response times for the line (8) and mixer / dispenser (3).

[0220] The system has pre-stored operating profiles (material / contaminant type, pulse frequency ƒ, duty cycle D, pressure and flow setpoints) that the operator selects and activates via the operator panel (25); the profile execution is ensured by the controller / PLC (29) with control of the valve (26) and the dispenser (3).

[0221] Also automatically records starts / stops, alarms for the temperature sensor (27) and pressure sensor (28), deviations for the air flow sensor (23), as well as the current state of the valve (26) and the dispenser (3) with a time stamp and the cause of the event.

[0222] This design of the control and regulation system (24) ensures the maintenance of the calculated flow parameters and the flexible formation of the cryo-jet cleaning mode, increasing the repeatability of the result and reducing CO2 consumption while maintaining the processing efficiency.

[0223] A quick-release fitting is installed at the outlet of the mixing unit for connection to the blaster pistol-manipulator (4). Fig. 5a, 6, c, d shows the pistol (4), which is equipped with a landing interface for replaceable nozzles (5, 6, 7), including straight-through, expanding and angular.

[0224] The spray gun (4) features a handle with an internal feed channel for the mixture. The spray gun (4) is connected to the pneumatic line (8) via a standard shank / BRS. A quick-change mounting interface on (4) (bayonet / thread) allows for quick, tool-free replacement of nozzles (5, 6, 7). The internal channels of the nozzles (5, 6, 7) are optimized for minimal losses and uniform acceleration of the granules. The nozzle material is wear-resistant (polymer / composite) and resistant to abrasive and cryogenic effects.

[0225] Let's consider the design of replaceable nozzles (5, 6, 7).

[0226] Straight nozzle (5) provides maximum axial velocity and dynamic pressure in the spot, high "range". Geometry: cylindrical / weakly confuser insert with a short straightening section; outlet diameter d вых Typically 4-12 mm; jet divergence angle ≤5°. Used for localized cleaning of areas with strong dirt adhesion, removing thick coatings, and processing edges. Optimum distance 25-200 mm.

[0227] The diverging (expanding) nozzle (6) features a converging throat and diffuser with an outlet expansion (opening angle of 6-15°) for controlled cross-sectional enlargement; a slotted version is also available for forming a "flat" jet. This configuration provides an increased contact area with a moderate reduction in peak velocities; uniform surface cooling. It is used for processing large areas, delicate materials (plastics, painted substrates), and final cleaning without etching. Optimum distance: 50-300 mm.

[0228] The angle nozzle (7) features a 30-90° elbow / channel bend (preferably 45° and 90°), with a profiled bend to minimize losses; a version with a rotating "head." This configuration provides access to hidden / end surfaces, maintaining an effective flow rate after the bend. Suitable for processing grooves, cavities, the back sides of ribs, and areas with limited access. The optimal distance is 30-150 mm; a transverse "sweeping" trajectory is convenient.

[0229] The nozzles are attached to the gun-manipulator (4) on a quick-change interface (bayonet / 1 / 4-turn) without tools, with positioning on a keyway stop. Preferred materials: wear-resistant polymers / composites (filled polyamide, PEEK, polyurethane) or hard-anodized aluminum alloys; internal channels are designed with low adhesion / friction and equipped with straightening inserts (honeycomb structures) and radius fillets to reduce turbulence and local losses. The choice of nozzle determines the jet profile (spot / strip / angular access) and the intensity-area ratio and is carried out in conjunction with the pressure and pulse profile settings (frequency ƒ, duty cycle D) of the control system (24, 29).

[0230] It should be noted that the above description of the design and operation of the integrated cryojet cleaning system (see Figs. 1-5 a, 6, c, d) illustrates only one possible embodiment. It is obvious to those skilled in the art that, while maintaining the stated set of essential features, the specific design solutions of individual components—the shape and materials of the nozzles, the type of dispenser, the design of the control system, the method of arranging and placing the elements on the frame—can be varied without departing from the essence of the invention, as defined by the claims. Both stationary and mobile versions of the unit are possible, along with various configurations of pneumatic preparation units and control systems that ensure the same technical result.

[0231] Example 1 “Intensive local cleaning” (metal, stubborn dirt).

[0232] Design: mobile system on a frame with a built-in compressor, receiver and pneumatic preparation unit (refrigeration dryer + coalescent filter) → auger-type dispenser → gun-manipulator with a straight nozzle.

[0233] CO2 granule size: 2-3mm; cylindrical granules, with a bulk density of 900-1100 kg / m3 3 .

[0234] Dispenser inlet pressure: 1.2-1.6 MPa.

[0235] Outlet jet speed: 250-300 m / s.

[0236] Feed mode: continuous (no pulse), closed loop pressure and flow are enabled.

[0237] Nozzle: straight, d o ut=8-10 mm, divergence angle ≤5°, distance to the surface 50-120 mm.

[0238] Control of granule flow rate: by the speed of the dispenser drive and / or by the weight of the hopper.

[0239] Metal-Hard Mode: This is a preset profile (recipe) in the electronic control system, containing setpoints for a pressure of 1.4 MPa, an air flow of 250 l / min, a granule feed rate of 0.07 kg / s, a straight nozzle selection, and a continuous feed mode without pulses. The controller automatically activates the corresponding parameters and controls the dispenser and valve according to this profile.

[0240] The device operates as follows.

[0241] On the operator panel, select the "Metal-Hard" profile, after which the system automatically sets the preset pressure, flow rate, and pellet feed rate. The pressure and flow control circuits are activated, ensuring the parameters are stabilized within acceptable limits. The compressor supplies air to the receiver, from where the flow is directed to the pneumatic preparation unit, where it undergoes drying and fine filtration. The treated air is fed to the auger-type dispenser. The auger speed is set by the controller based on the selected profile and ensures a mass flow rate of CO2 pellets of approximately 0.06-0.08 kg / s.

[0242] Granules measuring 2-3 mm in size flow by gravity from a heat-insulated hopper into the dispenser channel and are uniformly introduced into the compressed air flow, forming a homogeneous two-phase mixture. The mixture is then directed through a pneumatic line to a spray gun with a straight nozzle.

[0243] A jet with a velocity of approximately 270 m / s and a diameter of approximately 9 mm forms at the nozzle outlet. Upon impact with the metal surface, the contaminated layer instantly cools to -70…-78°C, becoming embrittled and fractured due to thermoelastic stress and the sublimation expansion of CO2. The removed contaminant particles are carried away by the air flow.

[0244] This results in rapid removal of thick, firmly adhered layers on the edges and ribs of metal parts without abrasive wear of the base.

[0245] Example 2 “Delicate area cleaning” (painted, polymer and composite surfaces).

[0246] Design: mobile or stationary system with the compressor unit, receiver, pneumatic preparation unit (refrigeration dryer + coalescent filter), modular disc-type dispenser, pneumatic line and a manipulator gun with a slot or diffuser nozzle mounted on the frame.

[0247] CO2 granule size: 0.5-1.0mm; finely dispersed granules, spherical or cylindrical in shape, providing a soft effect and uniform flow distribution.

[0248] Dispenser inlet pressure: 0.6-0.8 MPa.

[0249] Outlet jet speed: 120-180 m / s.

[0250] Feed mode: pulse, with frequency and duty cycle control, synchronized with the operation of the dispenser.

[0251] Nozzle: slot or diffuser; opening angle 6-15°, outlet slit (width 8-12 mm, length 30-60 mm); distance to surface 120-250 mm.

[0252] Pellet consumption control: based on signals from the feeder drive speed sensor and readings from the hopper weight sensor.

[0253] Soft-Wide Mode: A preset profile (recipe) for gentle processing of large surfaces. The profile includes the following settings: pressure of 0.7 MPa, air flow of 180 l / min, pulse frequency of 8 Hz, duty cycle of 40%, granule feed rate of 0.03 kg / s, slot nozzle selection, and closed-loop pressure and flow control. The controller automatically activates the profile parameters and coordinates the pulse valve and dispenser to maintain synchronous feed.

[0254] The operation of the device according to example 2 is as follows.

[0255] On the operator panel, select the "Soft-Wide" profile, after which the system automatically sets the pressure, flow, frequency, and pulse duty cycle settings. The pressure and flow control loops are activated. The compressor generates an air flow, which, after passing through the receiver, is dried and filtered in the air preparation unit, lowering the dew point and preventing moisture condensation. The treated air enters the control valve, which generates a pulsed flow with a set frequency of 8 Hz and a duty cycle of 40%.

[0256] The controller simultaneously controls a disc-type dispenser: CO2 granules 0.5-1 mm in size are evenly injected into each open pulse phase and accelerated by a compressed air flow, forming a soft two-phase jet. The mixture is fed through a pneumatic line into a gun-manipulator with a slot nozzle installed. At the nozzle outlet, a jet is formed at a speed of approximately 150 m / s, creating uniform cooling of a 40-50 mm wide surface area. During the pulse opening phase, the contaminated layer is briefly cooled to -60…-70°C, cracking and separating from the base, and during the pause, pressure is restored and the channel self-cleans. This alternating process increases efficiency due to increased thermal shock while simultaneously reducing average CO2 consumption and noise.

[0257] Removed dirt particles are carried away by the air flow; the surface remains dry and without mechanical damage.

[0258] Thus, the use of the stated system ensures gentle and uniform cleaning of painted, plastic, composite or thin-walled surfaces without etching or deformation, as well as final cleaning and degreasing of products in the electrical and aviation industries.

[0259] Taking into account the novelty of the set of essential features, the technical solution to the problem, the inventive step and the materiality of all general and particular features of the invention proven in the section “Prior Art” and “Disclosure of the Invention”, the technical feasibility and industrial applicability of the invention proven in the section “Implementation and Industrial Realization of the Invention”, the solution to the inventive problems and the confident achievement of the required technical result during the implementation and use of the invention, in our opinion, the claimed group of inventions satisfies all the requirements of protectability imposed on inventions.

[0260] The analysis also shows that all general and particular features of the invention are essential, since each of them is necessary, and all together they are not only sufficient to achieve the purpose of the invention, but also make it possible to implement the invention industrially.

Claims

1. A cryo-jet cleaning system for surfaces comprising a thermally insulated hopper for carbon dioxide granules, a dispenser for introducing granules into a compressed gas flow, a pneumatic line and at least one hand-held manipulator gun with replaceable nozzles, characterized in that it is equipped with a pneumatic preparation unit with gas drying and filtration, a receiver and a pressure regulator and an electronic control system configured to set the flow rate of granules, pressure and / or flow rate of compressed gas and select a mode of continuous or pulsed supply of a cleaning jet with setting programmable frequency and duty cycle profiles, wherein the dispenser is made modular with the possibility of implementing at least one of the dosing mechanisms: auger, disk, shaft or pneumatic.

2. The system according to paragraph 1, characterized in that the pneumatic preparation unit contains a refrigeration dryer and a fine coalescent filter.

3. The system according to paragraph 1, characterized in that it is equipped with a control / pulse valve, designed with the possibility of forming a pulse mode in the air duct with synchronization of the operation of the dispenser.

4. The system according to paragraph 1, characterized in that it is made in a mobile or stationary version.

5. The system according to paragraph 4, characterized in that in the mobile version it contains a frame / chassis with the placement of a compressor, receiver and control system.

6. The system according to paragraph 1, characterized in that the gun-manipulator is made with an interface for quickly changing nozzles of various geometries, including straight, expanding and angular.

7. The system according to paragraph 1, characterized in that the source of compressed gas is built-in - a compressor on a frame and / or external - main gas, with automatic source switching.

8. The system according to paragraph 1, characterized in that air, nitrogen and / or inert gas is used as the compressed gas.

9. The system according to paragraph 1, characterized in that the pneumatic preparation unit additionally contains an adsorption dryer with automatic drainage.

10. The system according to paragraph 1, characterized in that the hopper is equipped with a vibration activator and / or antifriction inserts to prevent caking of granules.

11. The system according to claim 1, characterized in that the pneumatic line contains quick-release connections and / or rotary couplings for quick changeover.

12. The system according to paragraph 1, characterized in that the dispenser module is made quickly removable with a unified connection interface for the interchangeable installation of a screw, disk, shaft or pneumatic mechanisms.

13. The system according to claim 1, characterized in that it is equipped with a position / speed sensor for the dispenser drive and / or a hopper weight sensor with mass flow calculation to ensure control of the granule flow rate based on signals.

14. The system according to claim 1, characterized in that it contains a mixing zone made with rounded joints and an anti-adhesive coating, eliminating dead zones and hanging of granules.

15. The system according to paragraph 1, characterized in that the gun-manipulator is equipped with a safety button and a start lock in the absence of pressure / flow.

16. The system according to claim 6, characterized in that the nozzle fastening interface is made in the form of a quick-change bayonet connection / key positioning with 1 / 4 turn.

17. The system according to paragraph 6, characterized in that the nozzles are made of a wear-resistant polymer / composite and / or metal with a hardening coating, with straightening inserts and radius channel connections.

18. The system according to paragraph 6, characterized in that the nozzle is made in the form of a rotating angular nozzle with a flow deflection angle in the range of 30-120°.

19. The system according to claim 6, characterized in that it additionally contains a slot nozzle for forming a flat jet when processing areas.

20. The system according to paragraph 1, characterized in that the electronic control system implements closed loops for pressure and / or flow with digital filtering of measurements, limiting the rate of change of the signal and protection of the integrator.

21. The system according to claim 1, characterized in that it is equipped with a valve that generates a pulse mode, designed with control of the pulse mode frequency in the range of at least 0.5-30 Hz and a duty cycle of 10-90% with synchronization of the supply of granules by the dispenser.

22. The system according to claim 1, characterized in that it contains recipes / profiles of feeding modes with a set of settings, such as type of material, pressure / flow rate, frequency and duty cycle, selected from the operator panel.

23. The system according to paragraph 1, characterized in that it is equipped with gas flow, pressure and temperature sensors with parameter indication and event logging in the form of starts, accidents, and deviations.

24. The system according to paragraph 1, characterized in that it is made in a noise-absorbing casing with ventilation and / or thermal screens.

25. The system according to claim 1, characterized in that it contains a remote wired and / or wireless interface for monitoring and updating profiles.

26. The system according to claim 1, characterized in that it contains at least two manipulator guns with flow switching or parallel operation.

27. The system according to paragraph 1, characterized in that it is equipped with a bypass purge line for cleaning the lines from condensate and particles.

28. The system according to paragraph 1, characterized in that the working pressure of the compressed gas at the inlet to the dispenser is 0.4-1.8 MPa.

29. The system according to claim 1, characterized in that the jet velocity at the nozzle outlet is 100-300 m / s.

30. The system according to claim 1, characterized in that the size of the CO2 granules is in the range of 0.5-5 mm in equivalent diameter.

31. A method for cryo-jet cleaning of surfaces, implemented using a system according to any one of paragraphs. 1-30, characterized in that carbon dioxide granules are fed from a thermally insulated bin into a stream of compressed air, the mixture is transported along a pneumatic line and ejected through a nozzle onto the surface being treated, while at least one parameter from the group is set by means of an electronic control system: mass flow rate of granules, pressure and / or air flow rate, continuous / pulsed feed mode, wherein in the pulsed mode a programmable profile is formed with specified frequency and duty cycle for adaptation to the type of material and contamination, ensuring the combined action of cryogenic cooling, kinetic impulse and sublimation expansion of carbon dioxide CO2.

32. The method according to paragraph 31, characterized in that the pulse mode profile is selected from among pre-stored recipes for typical materials / contaminants.

33. The method according to paragraph 31, characterized in that in the pulse mode, a valve is used that generates the pulse mode, wherein the opening frequency of said valve is selected within the range of 0.5-30 Hz, and the duty cycle is 10-90%.

34. The method according to paragraph 31, characterized in that before feeding the mixture, the air is dried and filtered to a specified dew point to prevent freezing.

35. The method according to paragraph 31, characterized in that a diffuser or slot nozzle is used for delicate surfaces, and an angled nozzle is used for hard-to-reach areas.

36. The method according to paragraph 31, characterized in that the pressure and / or gas flow is monitored in closed-loop mode and, when the parameters go beyond the set limits, the system is transferred to a safe mode.

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