WO2024191325A1 - Device and method for feeding bulk solid cryogenic material into a flow of compressed air - Google Patents

Abstract

The invention relates to cleaning contaminants from surfaces using a feeder. The present feeder comprises a housing having an inlet channel and an outlet channel for a flow of a compressed gas medium, a rotor mounted inside said housing and having at least one recess in the peripheral surface thereof, and a seal mounted inside the housing. The seal contains at least one first opening for receiving particles from a source at atmospheric pressure and feeding same into the recess in the peripheral surface of the rotor, at least one second opening for releasing said particles from said recess into a transport flow at a pressure above atmospheric pressure and receiving part of the transport flow into the recess, and at least one through-channel for pressure relief having at least one filter element. The pressure relief channel with a filter element is arranged in the direction of rotation of the rotor. The invention extends the working life of the rotor and seals as they become worn.

Description

DEVICE AND METHOD FOR FEEDING A BULK SOLID CRYOGENIC SUBSTANCE INTO A COMPRESSED AIR FLOW

Field of technology

The claimed invention relates to mechanical engineering, in particular to devices for cleaning surfaces from contamination, and can find application in various industries: automotive, aircraft, shipbuilding, nuclear industry, foundry, mechanical engineering, chemical and oil and gas, food, printing, light, power engineering and electronics. Namely: for cleaning pumps and tanks, oil field equipment; removing various organic coatings and contaminants (varnishes, paints, oils, wax, mastic, mold, algae, glue, soot and other deposits); cleaning from rust; removing graffiti from walls; cleaning electrical equipment: generators, electric motors, fans, compressors, radiators, printed circuit boards; cleaning press molds, ingot molds, core boxes in the foundry industry; cleaning automobile units at car washes; cleaning process equipment in the food industry; removing radioactive contamination. The surface being cleaned can be metal, glass, plastic, rubber, brick, etc.

State of the art

Dry ice cleaning is effectively used in a wide range of practical applications - from slag removal to cleaning printed circuit boards. This cleaning method can be successfully used for operating equipment without damage and dismantling, which significantly reduces its downtime.

Unlike conventional toxic chemicals, high-pressure water, and abrasive blasting, cryogenic blasting uses dry ice particles in a high-velocity air stream. There are no technological inconveniences associated with the processing of secondary raw materials and waste disposal. The physics of the carbon dioxide blasting process is as follows. Dry ice particles are accelerated in a carrier, which is compressed air. In this way, dry ice blasting is essentially similar to sandblasting. Since dry ice has a relatively low density, the process relies on the high velocity of the particles to obtain the necessary impact energy. When it hits a surface, the dry ice sublimates (evaporates), and an extremely rapid heat exchange process occurs between the ice granules and the surface. No moisture is formed during the evaporation of dry ice. The gas then expands hundreds of times compared to the volume of granulated dry ice during several milliseconds, causing a micro-explosion at the point of impact, which destroys the contaminant. Due to the large temperature difference between the ice particles and the surface being cleaned, a thermal shock also occurs, destroying the contaminant coating. This phenomenon is especially evident when processing non-metallic coatings, such as paint on a metal substrate.

Shot blasting systems have been around for decades. Typically, particles are fed into a conveying gas stream and transported as entrained particles to a blast nozzle, from which the particles exit, heading toward the workpiece or other target.

Carbon dioxide systems, including devices for creating carbon dioxide particulates, for introducing the particulates into a carrier gas, and for directing the entrained particulates toward an object, are well known, as are various associated components such as nozzles, and are shown in U.S. Patents 4,744,181, 4,843,770, 5,018,667, 5,050,805, 5,071,289, 5,188,151, 5,249,426, 5,288,028, 5,301,509, 5,473,903, 5,520,572, 6,024,304, 6,042,458, 6,346,035, 6,695,679, 6,726,549, 6,739,529, 6,824,450, 7,112,120, 8,187,057, and 8,869,551, as well as U.S. Patent Provisional Application Serial No. 61/592,313, filed January 30, 2012, to a method and apparatus for dosing carbon dioxide into particles, 14/062,118, filed October 24, 2013. Although this patent specifically refers to carbon dioxide in explaining the invention, the invention is not limited to carbon dioxide, but can be applied to any suitable cryogenic material. Thus, references to carbon dioxide herein should not be limited to carbon dioxide, but should be read to include any suitable cryogenic material.

Many conventional cleaning systems include rotating elements such as rotors with cavities or pockets to transport particles into the transport gas stream. Seals are used to press against the rotor surface to maintain a pressure differential to minimize parasitic losses.

From WO 02/060647 A1 a feeder with a feed cylinder with cavities that transport cryogenic particles from a hopper to a Venturi is known, which takes the form of a conical inlet and a conical outlet, where in the intermediate space a roof-shaped element, the gap between the inlet and outlet cones, increases or decreases. The roof-shaped element is moved by means of gas pressure into the feed cylinder.

There are many known solutions for feeding dry ice particles into a compressed air flow - feeder designs. These solutions are divided into two main types: disk and rotary feeders. Disk feeders are based on a disk rotating around its axis with through holes along the periphery. Rotary feeders are based on a rotor rotating around its axis with pockets along the outer surface, such as patent RU2748313. The disadvantages of a disk feeder are the increased torque, due to which the disk feeder is sensitive to the moisture and water content in the compressed air flow, which can turn into water ice on the feeder disk and the torque is not enough to continue the rotation of the disk. An increase in the torque will affect the dimensions of the gear motor, which is undesirable for mobile cleaning systems. The rotary feeder has been proving its superiority over the disk feeder for more than 10 years due to its lower torque, which ensures continuous rotation even when water ice forms on the rotor. It is also important to note that rotary feeders have a greater self-sealing effect (multiplication of the seal from compressed air) and a longer sealing section through which compressed air can penetrate. Both of these parameters affect the resource of the feeder seal.

Controlling water and moisture in the compressed air flow is the most important task when preparing a cleaning system for operation.

To ensure low moisture content in compressed air, it is traditionally recommended to use refrigerated or absorption compressed air dryers. Absorption dryers create a lower dew point temperature in compressed air than refrigerated ones. Example: when compressing shop air at a flow rate of 1 cubic meter per minute, this means that we will get a compressed air flow with a water consumption of approximately 0.82 liters per hour. A refrigerated dryer will separate 0.76 liters of condensate per hour (91% of the original moisture flow) and will create a pressure dew point of +5 degrees Celsius. A desiccant dryer will separate 0.81 liters of condensate per hour (1.2% of the original moisture flow) and create a pressure dew point of -40 degrees Celsius. But at the same time, for the same air flow rate, adsorption dehumidifiers weigh much more, are larger in size and are more expensive, which is often inconvenient to use.

If the cleaning system operates on small cylindrical granules with a diameter of 1.6 and 3 mm, then usually the formation of water ice is not observed at normal compressed air consumption for cleaning, even in some cases without drying the compressed air. In the case of using the crushing technology, the situation changes dramatically. When crushing in any way (scraping with a blade, squeezing with rollers, cutting with knives as in patent RU2021109877 or PCT / RU2022 / 050080), the dry ice granule as a hard brittle the body creates very small dry ice crumbs when broken. These dry ice crumbs, which can be called flour, cool the parts of the cleaning system that the flour touches very strongly. The rotor is cooled the most in the feeder, since the crushed particles with flour are fed mainly from above onto the rotating rotor with pockets. Due to this, the rotor is frozen very strongly to temperatures close to the temperature of dry ice. After the rotor turns, the pocket, which contains crushed particles and dry ice flour, enters the compartment with moving compressed air. The compressed air washes the dry ice out of the pocket with its flow. At the same time, so that the compressed air does not escape from the cavity, the seal presses on the rotor due to the force from the pressure of the same compressed air. The lower seal traditionally repeats the peripheral cylindrical smooth surface of the rotor and is pressed against it, which ensures the tightness of the supply of dry ice into the compressed air flow. Compressed air contacts the rotor surface, which has a temperature much lower than the dew point of compressed air, regardless of the desiccant used. Microdroplets of water suspended in the compressed air flow contact the frozen surface of the rotor. Upon contact, the microdroplets chaotically adhere to the rotor surface and freeze an uncontrolled thickness of water ice deposits on the cylindrical surface of the rotor. These deposits push the entire sealing surface of the lower seal away from the original metal surface of the rotor. As a result, compressed air begins to leak between the water ice deposits and eventually penetrates partially into the dry ice feed area above the rotor. When compressed air blows from the gap between the rotor surface and the sealing surface that contacts the rotor, it blows the dry ice upward, which prevents the dry ice from entering the rotor pockets normally. This in turn creates uneven supply of dry ice into the compressed air, reduces dry ice consumption, creates dry ice accumulations inside the frame of the cleaning system and can lead to improper operation of the system as a whole.

The next difficulty of dry ice crushing cleaning systems is the limited flow rate of dry ice supplied to the compressed air flow. It would seem that it is possible to increase the supply of crushed dry ice to the rotor pockets by, for example, increasing the rotor speed. But even if the pockets are completely clogged before they are moved to the compressed air cavity, but the rotor has a high rotation speed, then the time the pocket stays in the compressed air cavity becomes too short, and some of the dry ice remains in the pocket. This is also due to the fact that small particles are lighter and are more easily captured by compressed air flows and swirls compared to inert heavy 3 mm granules. As a result Turbulent flows of compressed air with captured microparticles and dry ice particles are locked in the pocket when returning to the granule feeder area.

It is worth remembering that in cleaning systems with 3 mm granules, which are inert and heavy compared to fine particles and flour, the seal has a channel for the exhaust of compressed air from the pocket when returning to the dry ice feed area. If the exhaust is not carried out, the compressed air will again blow away the dry ice particles, as described earlier. In this case, the exhaust channel usually has a sufficiently large cross-section, which is proportionate to the 3 mm dry ice granules, to ensure the guaranteed exhaust of compressed air, since the rotor rotates quickly.

In the case of crushed particles and at relatively high rotor speeds, the particles remain in the pocket, and when using the exhaust channel as for 3 mm granules, these particles fly out of the channel together with compressed air. This is due to the fact that small crushed particles (dry ice chips) are of different sizes when crushing granules and a dry ice block. When washing out the particles from the pockets with compressed air, a heterogeneous mixture with a high degree of particle distribution in the compressed air is obtained, when, unlike 3 mm granules, which have a low distribution of the mass of granules in the volume of compressed air. And since the compressed air remains in the pockets, then when exhausting, there is, in fact, an exhaust of not pure air and a heterogeneous mixture of compressed air and dry ice particles. As a result, particles accumulate in the machine frame and there is a loss of dry ice during cleaning. In this case, when reducing the cross-section of the exhaust channel to a smaller particle size, it will also be necessary to reduce the rotor speed, since the pockets will not have time to discharge compressed air through the narrow exhaust channel.

Another difficulty in the operation of cleaning systems is the wear of the seal and the feeder rotor due to foreign solid objects and dirt other than dry ice getting into the bin. As a result of abrasion, annular grooves/furrows appear on the surfaces of mainly the rotor and the lower seal, through which compressed air penetrates into the dry ice feed area. The negative effects of this were also described above.

A feed device for a jet processing system is known from the prior art (US7112120, published 26.09.2006). The known particle feed system includes a feeder having a rotor with a plurality of pockets formed on the peripheral surface. The flow path of the transport gas additionally includes pockets, so that essentially all of the transport gas flows through the pockets. A seal adjacent to the peripheral surface is actuated by the pressure of the transport gas, pressing its sealing surface against the peripheral surface of the rotor. When starting There is no significant pressure between the seal and the rotor, which reduces the starting torque requirements. Disadvantages of this invention: high hydraulic resistance for the flow inside the recess due to a sharp 180-degree turn, and from constantly alternating recesses for the passage of air. Due to vortices inside the recess, the particles will still not completely exit the recess. The exhaust channel is too large. There is no air discharge when ice builds up on the rotor.

A particle feed device is also known from the prior art (US10315862, published 11.06.2019). A device is described that introduces cryogenic particles obtained from a particle source having a first pressure into a moving transport fluid having a second pressure for final delivery to a workpiece or target as particles entrained in a transport fluid flow that is sealed between the particle source and the transport fluid flow. Disadvantages of this invention: too large exhaust channel. No air discharge when ice builds up on the rotor.

Also known from the prior art is a jet cleaning device (US4947592, published 14.08.1990). The device and method for jet cleaning of particles using sublimable pellets as a dispersed medium are described as having a source of sublimable pellets, a housing defining an internal cavity with spaced stations for receiving and unloading pellets, and a radial transport rotor for transporting pellets from the receiving station to the unloading station. The radial transport rotor additionally includes a plurality of transport cavities, each of which is formed on the peripheral surface of the radial transport rotor for receiving granules for radial transportation between the receiving and unloading stations. The receiving station communicates with the source of sublimable pellets and has a mechanical feed of pellets into the transport cavities. Disadvantages of this invention: too large an exhaust channel. No air discharge when ice builds up on the rotor.

The essence of the invention

The problem solved by the claimed invention is the creation of a reliable and highly productive device for cleaning with dry ice, which will ensure the maximum continuous operation of the feeder from the moment of warm start-up with or without the use of a compressed air dryer.

The technical result of the claimed invention consists in increasing the reliability and productivity of the dry ice cleaning process, increasing the flow rate of crushed dry ice through the feeder, and extending the service life of the rotor and seals when they wear out. The technical result of the claimed group of inventions is achieved due to the fact that the feeder comprises: a housing made with input and output channels for a flow of compressed gas medium, a rotor installed with the possibility of rotation around the axis of rotation in the housing and having a peripheral cylindrical surface; wherein the rotor is provided with at least one recess made on the said peripheral surface; a seal hermetically installed in the housing, having an internal cylindrical surface contacting with at least a part of the said peripheral surface of the rotor, wherein the said seal comprises at least one first opening for receiving particles from the said source with atmospheric pressure and for feeding the said particles with atmospheric pressure into the said recess formed on the peripheral surface of the rotor, at least one second opening for dispensing the said particles into the said transport flow with a pressure higher than atmospheric pressure from the said recess and receiving a part of the said transport flow inside the recess with subsequent pressure increase in the recess, and at least one through pressure relief channel, and at least one filter element located in the said channel, wherein at least one pressure relief channel with the filter element is located in the direction of rotation of the rotor between the opening for dispensing the said particles and the opening for receiving particles with atmospheric pressure.

In a particular case, for implementing the claimed technical solution, the feeder contains at least two through pressure relief channels, each of which contains at least one filter element located in the said channel, wherein the second said pressure relief channel with the filter element is located in the direction of rotation of the rotor between the opening for receiving particles with atmospheric pressure and the opening for dispensing at least a portion of the said particles.

In a particular case, for implementing the claimed technical solution, the said rotor is designed with the possibility of rotation around its axis, wherein the said channel with the filter element is located in the direction of rotation of the rotor between the opening for dispensing the said particles and the opening for receiving particles with atmospheric pressure.

In a particular case, for the implementation of the claimed technical solution, the said seal consists of two parts made with an internal cylindrical surface in contact with the said peripheral surface of the rotor, while the said filter element is made integral with one of the said parts of the seal, while the filter surface is a continuation of the internal cylindrical surface in contact with the said peripheral surface of the rotor.

In a particular case, to implement the stated technical solution, the filter element is made in the form of a plurality of slits in the form of cracks made in the walls of the said part of the seal, with the gap of each crack being sufficient to retain at least a portion of the said particles.

In a particular case, to implement the stated technical solution, the mentioned slots are arranged randomly or arranged in the form of a linear array with equal pitch.

In a particular case, to implement the claimed technical solution, the filter element is formed at the entrance to the through discharge channel and is made in the form of a plurality of holes made in the walls of the said part of the seal, while the holes are made with a cross-section sufficient to retain at least part of the said particles.

In a particular case, to implement the stated technical solution, the mentioned holes are made in a round format.

In a particular case, to implement the stated technical solution, the mentioned holes are located randomly or in the form of a rectangular array with equal pitch.

In a particular case, for implementing the claimed technical solution, the said rotor is installed inside the said feeder housing on bearings, wherein the bearings are installed in the walls of the housing, wherein a cover is made in one wall of the housing, wherein the bearing located in the wall opposite the wall equipped with the said cover is made with an outer diameter smaller than the outer diameter of the rotor, and the outer diameter of the rotor is made smaller than the outer diameter of the bearing located in the wall of the housing equipped with the said cover.

In a particular case, to implement the stated technical solution, the feeder body is rigidly connected via a flange to the gearbox, thereby the gearbox body and the feeder body form a rigid assembly, while the gearbox is made of a worm type, and the motor is a three-phase electric motor.

In a particular case, to implement the claimed technical solution, the housing is made with an internal cavity formed by the walls of the housing, wherein the said cavity at the point of mating with the said seal is made to taper inward, and the said seal at the point of mating with the said housing is made with a continuous closed internal groove along its outer surface, into which a sealing ring is installed. The technical result of the claimed group of inventions is achieved due to the fact that the method includes the stages of: ensuring constant rotation of said rotor, feeding at atmospheric pressure through an opening for receiving and feeding from a particle source a first portion of said particles to at least one recess formed on the peripheral surface of the rotor; delivering by means of at least one recess a portion of the first portion of said particles through an opening for delivering said particles into said transport flow with a pressure higher than atmospheric and receiving a portion of said transport flow inside the recess with subsequent raising of the pressure in the recess, wherein the second portion of the first portion of said particles is retained in said at least one recess, before feeding the second portion of said particles into said at least one recess; the pressure in said at least one recess is released to atmospheric pressure by means of at least one through channel configured to release the pressure in said recess to atmospheric pressure, while retaining by means of at least one filter element a second portion of said first fraction of particles in at least one recess formed on the peripheral surface of the rotor; feeding a second portion of said particles into at least one recess formed on the peripheral surface of the rotor, while mixing said second portion of the first fraction of particles with the fed second fraction of said particles; and delivering said particles into said transport flow.

In a particular case, to implement the claimed technical solution, the said rotor is provided with constant rotation around its axis, while the pressure is released through the said channel, configured to release the pressure, located in the direction of rotation of the rotor between at least one opening for dispensing the first portion of the said particles and at least one opening for receiving particles with atmospheric pressure.

In a particular case, to implement the stated technical solution, pre-crushed particles of a solid cryogenic substance are used as the mentioned particles.

Brief description of the drawings The details, features, and advantages of the present invention follow from the following description of embodiments of the claimed technical solution using drawings showing:

Fig. 1 shows a mobile device for cleaning with dry ice;

Fig. 2 shows a mobile device for cleaning with dry ice;

Fig. 3 shows a mobile device for cleaning with dry ice without external casing and without part of the power structure;

Fig. 4 shows the connection of the feeder to other units of the cleaning system.

Fig. 5 shows a feeder with a gear motor in section along a vertical plane passing through the rotor axis.

Fig. 6 shows an explosive assembly of the feeder, as well as an assembly of the feeder without the feeder housing to facilitate understanding of its structure.

Fig. 7 shows a section of a feeder based on the present technical solution.

Fig. 8 shows the first version of the technical embodiment of the filter element in the form of a solid upper seal with thin walls.

Fig. 9 shows the second version of the technical embodiment of the filter element in the form of a solid upper seal with a thin wall.

Fig. 10 shows the moment when particles of different sizes enter the rotor pocket.

Fig. 11 shows the moment of washing out the main part of the quantity of dry ice particles from the air, the direction of movement of which is indicated by the arrow “Air”.

Fig. 12 shows the moment of compressed air exhaust from the pocket through the cracks and retention of particles;

Fig. 13 shows the moment of return of a portion of dry ice particles to the pocket for receiving a new portion of dry ice particles.

Fig. 14 shows protection against air penetration into the bunker.

The following structural elements are indicated by numbers on the figures:

1 - Machine body; 2 - Operator handle; 3 - Particle dispersal nozzle; 4 - Control cable; 5 - Jet hose for supplying part and gas medium; 6 - Power cable; 7

- Hose for supplying gas from the source; 8 - Hopper hatch; 9 - Control panel; 10

- Hose connection adapter; 11 - Jet hose connection adapter; 12 - Hopper (Particle source); 13 - Chopper gear motor; 14 - Feeder gear motor; 15

- Gas pressure reducer; 16 - Feeder; 17 - Chopper; 18 - Air inlet/outlet; 19 - Air outlet/inlet; 20 - Feeder body; 21 - Upper seal; 22 - Lower seal; 23 - Rotor; 24 - Particle feed hole; 25 - Particle outlet hole; 26 - Pressure relief channel #1; 27 - Pressure relief channel #2; 28 - Particle mixing sleeve; 29 - Pneumatic cylinder; 30 - Pressure plate; 31 - Bearing #1; 32 - Bearing #2; 33 - Rotor stop cover; 34 - Recess; 35 - Filter element; 36 - Channel for seal ring; 37 - Rotor outer peripheral surface; 38 - Inner cylindrical seal surface; 39 - Particle share; 40 - Direction of rotor rotation; 41 - Solid seal body (without filter); 42 - Exhaust channel filter; 43 - Transport compressed gas flow; 44 - First part of the first particle fraction; 45 - Second part of the first particle fraction; 46 - Compressed gas exhaust from the recess through the filter and channel; 47 - Leakage of compressed gas medium due to wear of the cylindrical seal surface or water ice build-up on the rotor surface; 48 - Exhaust leakage of compressed gas medium through filters;

Disclosure of invention

Fig. 1 shows a dry ice cleaning system with a jet hose, electric power cable, control cable, compressed air hose, operator handle and nozzle connected to it. The cleaning system's function is to supply dry ice and then compressed air to the cleaning nozzle. Then the operator, holding the operator handle with the connected nozzle, runs a jet of compressed air with dry ice particles over the contaminated surface and removes contaminants from it. The operator handle can switch on the following functions: protection against unintentional start; activation of air and granule supply; adjustment of granule supply flow; switching on lights for illuminating the cleaning surface.

Fig. 2 shows a system for blast cleaning with dry ice particles. The system has a frame, handles, wheels, a hatch, and an operator panel. The system frame also has doors for access to the electrical control system. At the bottom of the frame, on one side, there is an adapter for connecting compressed air from a compressed air source, on the other side there is a quick-release connection for connecting a jet hose, a socket for connecting a control cable, a socket for connecting power, and a tap for releasing pressure from the system. The operator panel may contain the following elements: an indicator of incoming compressed air pressure; a handle for adjusting the compressed air pressure for cleaning; a cleaning pressure indicator; a system power button; an emergency button; an hour meter.

Fig.3 shows the cleaning system without the outer casing and part of the power structure. The hatch serves as a high-quality protective measure against dust and dirt during transportation, storage and operation of the cleaning system. A bunker is provided under the hatch. for storing filled granules, for example, with a diameter of 1.6 to 20 mm. A crusher is installed at the bottom of the hopper, for example, a crusher with rotating knives from patent RU2021109877 (PCT / RU2022 / 050080), which crushes granules, for example, with a diameter of 1.6 to 20 mm to the required size due to replaceable sieves with a gap, for example from 1.5 to 3.5 mm. The hopper is equipped with a vibrator to prevent granules from sticking together during storage in the hopper. As a result of a certain number of iterations of cutting by rotating knives, particles of the required size pass through the sieve. After that, the built-in impeller from patent RU2021109877 (PCT / RU2022 / 050080) throws the particles into a channel that directs the particles to the dry ice supply area of the feeder. The gear motors drive the crusher and feeder independently of each other.

The use of the present invention can also be used without using a grinder of any type, namely using only cylindrical granules as a cleaning agent.

Fig. 4 shows the connection of the feeder to other units of the cleaning system. Compressed air is supplied through an adapter and enters the compressed air pressure regulator, which can be designed, for example, as a conventional pressure regulator with a movable membrane and pilot control, or as a standard ball valve with positioning of the angle of rotation of the ball with an opening using, for example, a rotary pneumatic drive.

Next, compressed air at the set pressure enters the feeder, where the air is mixed with dry ice particles.

The feeder is also connected to a gear motor, which makes the feeder rotor rotate. For example, the gear motor can be of a worm type, and the motor can be three-phase, where the rotor is adjusted using a frequency converter.

After the feeder, compressed air with dry ice particles enters the quick-release coupling, to which the jet hose is connected.

Fig. 5 shows a feeder with a gear motor in section along a vertical plane passing through the rotor axis. The rotor can be made of metal, preferably stainless steel AISI 304. The gear reducer sets the rotor in motion through its tail via a key (not shown). The feeder body is rigidly connected via a flange to the gear reducer, thereby the gear reducer body and the feeder body form a rigid assembly. The body can be made of any metal, for example, an aluminum alloy. The rotor is installed in a hollow body and is held in it by an external bearing and an internal bearing. The body is made as a prismatic cup, which has two through holes. Each hole is equipped with its own a metal bearing, preferably stainless steel and filled with grease. The bearings have different external diameters. In the internal hole there is a small protrusion against which the external ring of the internal bearing rests. Both internal rings of both bearings rest against the rotor. The external hole is made completely through, therefore, to prevent the external bearing from flying out of the housing, an end metal plate is provided, which is attached to the housing with bolts. Thus, the rotor is rigidly fixed along its axis.

The lower and upper seals are installed inside the cup, which can be made of antifriction material, such as PTFE or ultra-high molecular weight polyethylene PE1000. The upper seal is pressed against the rotor slightly. The upper metal plate is rigidly fixed to the upper part of the housing and does not allow the upper seal to rise up. The upper plastic also presses the bushings that hold the pneumatic cylinders with metal strikers. There are special cutouts in the upper seal for the bushings. The upper plate also has a place for installing a vibrator.

The strikers are installed only in case of operation of the cleaning system without using a crusher when cleaning with 3 mm granules. In this version, 3 mm particles completely cover the feeder feed area. And to prevent 3 mm granules from sticking together from leaking air from the lower seal, the strikers produce a reciprocating motion and the granules are constantly in a state of mixing. And the vibrator is installed when using a crusher to prevent the adhesion of particles and microparticles of dry ice accumulated in the feeder granule feed area when cleaning is stopped.

The housing has internal walls of the upper and lower levels. The upper level of the walls is stretched almost along the entire depth of the housing and ensures unidirectional movement without rotation of the upper and lower seals inside the housing. The lower level of the walls protrudes slightly inside the housing at the same distance along the perimeter and serves to seal the lower seal using an annular sealing ring, for example, made of NBR butadiene-nitrile rubber. At the same time, the height of the lower level of the walls is small and is sufficient only for sealing the ring. The scheme with two levels of walls ensures reliable installation and dismantling of the lower seal, since the sealing ring will not slide along the entire height of the inner walls of the housing, but only along the lower level of the walls. Also, for ease of dismantling the upper and lower seals, both seals have threaded holes for screwing bolts into them, by which the seals can be easily pulled out. Fig. 6 shows an explosive assembly of the feeder, as well as an assembly of the feeder without the feeder body to facilitate understanding of its structure.

This design also allows for more technologically advanced maintenance of the feeder to check for damage to the rotor and seals or to disassemble it to remove foreign objects. The increased technological efficiency consists in minimizing the risk of damage to the most critical surfaces: the rotor surface and the surface of the lower seals. This is achieved due to the fact that the outer diameter of the inner bearing is smaller than the rotor diameter, and the rotor diameter is smaller than the outer diameter of the outer bearing. As a result, when pulling out the rotor with bearings, the surface of the lower seal does not touch anything except the bearing surface, as well as the rotor surface.

Fig. 7 shows a section of a feeder based on the present invention. The right and left white parts are filter elements.

In this case, they can be either separate elements or part of the upper seal. If the filter elements are separate elements, then the complexity of manufacturing lies in creating a repeating cylindrical surface. Since in the case of a sufficiently large gap between the surface of the rotor and the filter element, microparticles can accumulate in this gap and stick together with water ice. As a result, the filter element will become clogged. And in the case of manufacturing the filter element as part of the upper seal, a single continuous contact surface with the rotor surface is obtained. This ensures cleaning of the filter element by the rotor itself.

Fig. 8 shows the first best embodiment of the filter element in the form of a solid upper seal with walls. These walls have a plurality of slots in the form of slits, where the gap of each slot is sufficient to retain at least a portion of the returned dry ice particles. The plurality of slots can be made in the form of a random arrangement, but it is desirable in the form of a linear array with an equal pitch to facilitate easy production with a disk cutter. After returning, the particles remain in pockets, which are refilled with dry ice for the next rotation of the rotor and the supply of dry ice to the compressed air flow.

Fig. 9 shows the second best variant of the technical embodiment of the filter element in the form of a solid upper seal with a thin wall. These walls have a plurality of holes of any shape, preferably round, where the cross-section of each hole is sufficient to retain at least a portion of the returned dry ice particles. The plurality of holes can be made in the form of a chaotic arrangement holes, but preferably in a rectangular array with equal pitch to facilitate easy production by drilling. After return, the particles remain in the pockets, which are refilled with dry ice for the next rotation of the rotor and the introduction of dry ice into the compressed air stream.

Another technical solution option may represent the first best technical solution, but with one filter element in the area of the required exhaust.

Another technical solution option may represent the second best technical solution, but with one filter element in the area opposite the required exhaust.

Another technical solution option may be any combination of the first and second best technical solutions.

Another variant of the technical solution may be a single body of the upper and lower seal and filter elements from the first or second best technical solution.

Fig. 10 - Fig. 13 show four frames of animation of the first best technical solution in operation. The right black element is part of the solid body of the upper seal. The rotor rotates clockwise.

The technical solution can be used to create equipment for cleaning with dry ice granules.

Using small dry ice particles has the following advantages over larger pellet sizes, such as 3mm diameter pellets, when cleaning:

- smaller particles accelerate faster and require a shorter distance to accelerate, which means shorter nozzles can be used;

- with small particles, nozzles with a smaller critical cross-section can be used, which ensures lower compressed air consumption;

- small particles penetrate better into narrow cracks;

- small particles have less inertia compared to 3 mm granules, and therefore clean more delicately and do not damage fragile surfaces;

- increases the density of dry ice mass distribution in the volume of compressed air, which reduces dry ice consumption;

- when using a crusher, it becomes possible to use large granules and blocks of dry ice, which have a lower evaporation rate compared to 3 mm granules. Fig. 14 shows protection against air penetration into the bin during freezing of the feeder rotor and during wear. During freezing of the rotor with water ice, air leaks from under the seal will pass through the side filter elements as shown in Fig. 14 without capturing dry ice particles from the rotor pockets, and as a result will not penetrate into the area of particle feed into the rotor pockets. In this way, dry ice particles will more stably enter the pockets and with fewer losses in the area of the filter elements reach the lower area, where they will mix with compressed air for cleaning. Such filter elements mentioned above perform the function of protection against rotor freezing, and some of the penetrating compressed air exits through the filters without reaching the particle feed.

When the rotor is frozen with ice, the lower seal moves down; in this case, ice does not grow uniformly on the rotor surface, but in islands; then air begins to penetrate from the granule feed area in all directions from under the rotor; the main purpose of protection is to prevent the air flow from entering the upper granule feed area; if there were no filter elements on both sides. This design solves the disadvantage of analogs that contain only one exhaust channel without a filter, due to which air exited through the exhaust channel to the side, but on the other side it flowed around the rotor and penetrated upward and interfered with the supply of granules; but at the same time, the air that would exit through the wide exhaust channel would throw out returning dry ice particles, or such a disadvantage, which provides that instead of a wide exhaust channel there would be one filter in comparison with the first disadvantage described above, then the returning particles would not fly away through the exhaust, but, on the other hand, the air would also penetrate upward.

The design, in order to eliminate the described shortcomings, could be improved in such a way as to install another exhaust channel with a filter on the other side (approximately mirrored or diametrically opposite), then the air there will also exit to the side and will not capture the particles that are fed. Thus, the exhaust will be carried out on both sides of the rotor, and the particles for feeding and returning will not be carried away from the rotor pockets.

This disclosure relates generally to continuous or nearly continuous movement of particles from a first region to a second region where there is a pressure difference between the regions, and to a device and method for sealing between the two regions during the movement of the particles.

Claims

Invention formula 1. A feeder configured to transport particles from a source into a transport flow of a compressed gas medium with a pressure higher than atmospheric, wherein said feeder comprises: a housing made with input and output channels for a flow of compressed gas medium, a rotor mounted with the possibility of rotation around the axis of rotation in the housing and having a peripheral cylindrical surface; wherein the rotor is provided with at least one recess made on said peripheral surface; a seal hermetically installed in the housing, having an internal cylindrical surface that contacts at least a portion of the said peripheral surface of the rotor, wherein the said seal comprises: at least one first opening for receiving particles from the said source with atmospheric pressure and for feeding the said particles with atmospheric pressure into the said recess formed on the peripheral surface of the rotor, at least one second opening for dispensing the said particles into the said transport flow with a pressure higher than atmospheric pressure from the said recess and for receiving a portion of the said transport flow inside the recess with subsequent pressure increase in the recess, and at least one through pressure relief channel, and at least one filter element located in the said channel, wherein the said at least one pressure relief channel with the filter element is located in the direction of rotation of the rotor between the opening for dispensing the said particles and the opening for receiving particles with atmospheric pressure. 2. The feeder according to claim 1, characterized in that said seal contains at least two through pressure relief channels, each of which contains at least one filter element located in said channel, wherein the second said pressure relief channel with the filter element is located in the direction of rotation of the rotor between the opening for receiving particles at atmospheric pressure and the opening for dispensing at least a portion of said particles. 3. The feeder according to item 1, characterized in that the said seal consists of two parts made with an internal cylindrical surface in contact with the said peripheral surface of the rotor, wherein the said filter element is made integral with one said part of the seal, wherein the filter surface is a continuation of the inner cylindrical surface in contact with the said peripheral surface of the rotor. 4. A feeder according to item 3, characterized in that the filter element is made in the form of a plurality of slits in the form of cracks made in the walls of the said part of the seal, wherein the gap of each crack is sufficient to retain at least a portion of the said particles. 5. The feeder according to item 4, characterized in that the said slots are arranged randomly or arranged in the form of a linear array with equal pitch. 6. A feeder according to item 3, characterized in that the filter element is formed at the entrance to the through discharge channel and is made in the form of a plurality of openings made in the walls of the said part of the seal, wherein the openings are made with a cross-section sufficient to retain at least a portion of the said particles. 7. The feeder according to item 6, characterized in that the said openings are made in a round shape. 8. A feeder according to item 6, characterized in that said openings are arranged randomly or in the form of a rectangular array with equal pitch. 9. The feeder according to item 1, characterized in that the said rotor is installed inside the said feeder housing on bearings, wherein the bearings are installed in the walls of the housing, wherein a cover is made in one wall of the housing, wherein the bearing located in the wall opposite the wall equipped with the said cover is made with an outer diameter smaller than the outer diameter of the rotor, and the outer diameter of the rotor is made smaller than the outer diameter of the bearing located in the wall of the housing equipped with the said cover. 10. The feeder according to item 1, characterized in that the feeder body is rigidly connected via a flange to the reducer, thereby the reducer body and the feeder body form a rigid assembly, wherein the reducer is of a worm type, and the motor is a three-phase electric motor. 11. The feeder according to item 1, characterized in that the housing is made with an internal cavity formed by the walls of the housing, wherein said seal at the point of mating with said housing is made with a continuous closed internal groove along its outer surface, into which a sealing ring is installed. 12. A method for transporting particles from a source into a transport flow of a compressed gas medium, implemented using a device according to claim 1, comprising the steps of: ensuring constant rotation of said rotor, feeding at atmospheric pressure through an opening for receiving and feeding from a particle source a first portion of said particles into at least one recess made on the peripheral surface of the rotor; issuing, by means of at least one said recess, a portion of the first portion of said particles through an opening for issuing said particles into said transport flow with a pressure higher than atmospheric pressure and receiving a portion of said transport flow inside the recess with subsequent pressure increase in the recess, wherein the second portion of the first portion of said particles is retained in said at least one recess, before feeding the second portion of said particles into said at least one recess, the pressure in said at least one recess is released to atmospheric pressure by means of at least one through channel configured to release the pressure in said recess to atmospheric pressure, wherein the second portion of said first portion of particles is retained in at least one recess formed on the peripheral surface of the rotor by means of at least one filter element, and the second portion of said particles is fed into at least one recess formed on the peripheral surface of the rotor, wherein said second portion of the first portion of particles is mixed with supplied by the second share of said particles, and release at least a portion of said particles into said transport flow. 13. The method according to claim 12, characterized in that, while ensuring constant rotation of said rotor around its axis, pressure is released through said channel configured to release pressure, located in the direction of rotation of the rotor between at least one opening for dispensing the first portion of said particles and at least one opening for receiving particles with atmospheric pressure. The method according to paragraph 12, characterized in that the said particles are pre-crushed particles of a solid cryogenic substance. 19