High-speed electric slip ring cooling system based on vortex tube refrigeration

Abstract

The invention discloses a high-speed electric slip ring cooling system based on vortex tube refrigeration, belongs to the field of electric slip ring cooling, and aims to solve the problems that water vapor and oil mist particles in the environment are combined to form an oily sludge mixture, so that the pressure and flow of airflow entering a vortex tube cannot meet rated working requirements, and the refrigerating capacity of the vortex tube is reduced. The high-speed electric slip ring cooling system based on vortex tube refrigeration solves the problems that heat dissipation of an electric slip ring core heating area (the contact position of an electric brush and a collecting ring) is insufficient, and the hot spot temperature rises in the prior art, and comprises an electric slip ring, a vortex tube communicated to one side of the electric slip ring, and a communicating tube communicated to the end, away from the electric slip ring, of the vortex tube. The air cylinder is used for driving the filter screen to do transverse and vertical reciprocating motion, and hot air generated by the vortex tube is used for reversely blowing the filter screen. Therefore, online cleaning and area switching of the filter screen are achieved, permeability of the filter screen can be maintained without shutdown, continuous and stable operation of the electric slip ring cooling system is guaranteed, and working efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric slip ring cooling, in particular to a high-speed electric slip ring cooling system based on vortex tube refrigeration. BACKGROUND

[0002] In the field of industrial production, high-speed electric slip rings are widely used in machine tool machining, wind power equipment, metallurgical machinery, ship power systems, mining machinery, and humid coastal / near-shore operating equipment, as the core components for realizing power transmission and signal interaction between rotating equipment and fixed equipment. In these application environments, due to the characteristics of production processes or the influence of natural environment, oil mist and water are commonly present in some working conditions. Specifically, in machine tool machining workshops, a large amount of cutting fluid mist and hydraulic oil mist is generated during the operation of numerical control machine tools and hydraulic equipment; in metallurgical and mining machinery operating environments, oil mist and dust, water vapor are mixed together due to the leakage of equipment lubrication systems; ship power systems and coastal / near-shore operating equipment are long-term exposed to high-humidity marine climates, and the air contains not only salt water vapor but also oil mist generated by the combustion of fuel oil; in humid areas, the air humidity of outdoor operating high-speed rotating equipment is often in a high saturation state, and it may also be contaminated by oil mist from surrounding industrial emissions.

[0003] To meet the cooling requirements of high-speed electric slip rings under high power density operation, cooling devices based on vortex tube refrigeration are widely used due to their advantages such as modular integration, no need for refrigerants, and strong adaptability. The core working logic of this device is to introduce external compressed air into the vortex tube, separate it into low-temperature cold gas flow and high-temperature hot gas flow through the vortex effect, and then pass the low-temperature cold gas flow into the electric slip ring to achieve precise heat dissipation. Since compressed air directly affects the refrigeration efficiency of the vortex tube and the safe operation of the electrical components inside the electric slip ring, it is necessary to pretreat the compressed air entering the vortex tube by filtering out impurities such as oil mist, dust, and water vapor to prevent the nozzle from being blocked, the energy separation efficiency from being reduced, or the electric brush from being worn out, causing short circuits in the collector ring.

[0004] However, in the above-mentioned specific environments containing oil mist and water, the use of filter screens faces significant bottlenecks. The combination of water vapor and oil mist particles in the environment forms an oil sludge-like mixture, further exacerbating the initial plugging of filter screen pores, which increases the air passage resistance of the filter screen, reduces the flow rate of compressed air, and makes the pressure and flow rate of the air entering the vortex tube unable to meet the rated working requirements, resulting in a decrease in the refrigeration capacity of the vortex tube and insufficient heat dissipation in the core heating area of the electric slip ring (the contact between the electric brush and the collector ring), causing the temperature at the hot spot to rise; as the degree of plugging intensifies, the filter screen may completely fail, causing air flow interruption or flow reduction, which not only causes the vortex tube refrigeration function to fail, but also may cause problems such as insulation aging and increased contact resistance due to the long-term overheating of the electric slip ring, and in severe cases, directly leads to the burning of the electric slip ring, affecting the stable operation of the entire rotating equipment system.

[0005] To solve the above problems, a high-speed electric slip ring cooling system based on vortex tube refrigeration is provided. SUMMARY

[0006] The purpose of the present application is to provide a high-speed electric slip ring cooling system based on vortex tube refrigeration, which solves the problem that water vapor in the environment combines with oil mist particles to form an oil sludge-like mixture, further exacerbating the initial plugging of filter screen pores, leading to increased ventilation resistance of the filter screen, reduced air flow of compressed air, and reduced flow rate, making the airflow pressure and flow rate entering the vortex tube unable to meet the rated operating requirements, resulting in a decrease in vortex tube refrigeration capacity, and insufficient heat dissipation in the core heating area of the electric slip ring (the contact between the brush and the collector ring), resulting in an increase in hotspot temperature.

[0007] To achieve the above purpose, the present application provides the following technical solution: a high-speed electric slip ring cooling system based on vortex tube refrigeration, comprising an electric slip ring, a vortex tube connected to one side of the electric slip ring, a communication pipe connected to the end of the vortex tube away from the electric slip ring, an outer shell connected to the end of the communication pipe away from the electric slip ring, a filter screen arranged on the inner side of the outer shell, a hot air outlet arranged on the outer side of the vortex tube, a push mechanism arranged on one side of the outer shell, a rotating mechanism arranged on the outer side of the push mechanism, and an air outlet pipe connected to the side of the outer shell away from the outer shell.

[0008] The rotating mechanism comprises a sliding assembly and a swinging assembly, and the swinging assembly is arranged on the inner side of the sliding assembly.

[0009] Preferably, the push mechanism comprises a first support plate fixedly connected to the outer side of the outer shell, a gas cylinder fixedly connected to the outer side of the first support plate, a gas rod fixedly connected to the output end of the gas cylinder, a fixed plate fixedly connected to one end of the gas rod, and the filter screen is arranged on one end of the fixed plate close to the vortex tube.

[0010] Preferably, the inner side of the fixed plate is provided with a sliding groove, the inner side of the sliding groove is provided with a sliding block, the sliding block is fixedly connected with the filter screen, the inner side of the fixed plate is provided with a first guide groove, the inner side of the first guide groove is provided with a first guide rod fixedly connected with the sliding block, the side of the outer shell close to the gas cylinder is provided with a first hole, the side of the outer shell close to the gas cylinder is provided with a baffle, and the inner side of the baffle is provided with a second hole for nesting.

[0011] Preferably, the width of the side of the sliding groove close to the gas cylinder is greater than the width of the side of the sliding groove away from the gas cylinder, and the outer side of the sliding groove is attached to the inner side of the sliding groove.

[0012] Preferably, the first guide groove is provided with point a outside the one end of the vortex tube, and is provided with point b inside the one end of the vortex tube, is provided with point c outside the other end of the vortex tube, and is provided with point d inside the other end of the vortex tube, the horizontal height of point a is higher than that of point b, and the horizontal height of point c is lower than that of point d.

[0013] Preferably, the sliding assembly comprises a connecting rod fixedly connected to the outside of the sliding block, one end of the connecting rod is fixedly connected with a push plate, the inside of the push plate is provided with a guide hole, the shell is vertically and slidingly connected with a push rod on the side close to the electric slip ring, and the inside of the guide hole is provided with a second guide rod fixedly connected with the push rod.

[0014] Preferably, the guide hole is in a wave shape, and the second guide rod and the second guide rod are in clearance fit.

[0015] Preferably, the swinging assembly comprises a nozzle rotatably connected to the outside of the communication pipe, the outside of the nozzle is fixedly connected with a sleeve, the inside of the sleeve is provided with a second guide groove, the inside of the second guide groove is provided with a third guide rod, the inside of the sleeve is provided with a push rod fixedly connected with the push rod, the shell is provided with a third hole for nesting the nozzle on the side close to the electric slip ring, the inside of the third hole is connected with a rubber sealing gasket, the hot air outlet is communicated with a air supply pipe of the nozzle, and the outside of the air supply pipe is provided with a cooling pipe.

[0016] Preferably, the second guide groove is in a spiral shape, and the third guide rod and the second guide groove are in clearance fit.

[0017] Preferably, the nozzle is symmetrically provided with two about the central axis of the communication pipe.

[0018] 1. Compared with the prior art, the beneficial effects of the present application are that the present application drives the filter screen to move horizontally and reciprocally up and down through the air cylinder, and the hot air generated by the vortex tube is used to blow the filter screen reversely. Thus, the online cleaning and area switching of the filter screen are realized, the permeability of the filter screen can be maintained without stopping, the continuous and stable operation of the electric slip ring cooling system is ensured, and the work efficiency is improved.

[0019] 2. The present application uses the filtered waste heat air generated in the vortex tube refrigeration process to blow the filter screen after temperature adjustment through the cooling pipe, the adhesion of oil stains and water vapor is reduced through heating, the discharge is promoted, the recycling of energy is realized, and external energy and secondary pollution are avoided.

[0020] 3. The present application shortens the residence time of pollutants on the filter screen through the online continuous cleaning mechanism of the filter screen, so that the pollutants are removed before being firmly adhered, the cleanliness of the filter screen is effectively maintained, and the pollution discharge efficiency is improved.

[0021] 4. The cooperation of the wave-shaped guide hole and the spiral-shaped second guide groove drives the nozzle to swing during the sweeping, thereby increasing the coverage of the hot air, making the cleaning air flow more evenly act on the filter screen surface, and further improving the discharge efficiency of oil stains and moisture. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall three-dimensional structure of the present application;

[0023] Figure 2 It is a schematic diagram of the appearance structure of the first guide groove of the present application;

[0024] Figure 3 It is a schematic diagram of the front view cross-sectional structure of the shell of the present application;

[0025] Figure 4 It is a schematic diagram of the rear view structure of the guide hole of the present application;

[0026] Figure 5 It is a schematic diagram of the front view cross-sectional structure of the sleeve of the present application;

[0027] Figure 6 It is a schematic diagram of the structure at A in the present application; Figure 1

[0028] Figure 7 It is a schematic diagram of the structure at B in the present application; Figure 3

[0029] Figure 8 It is a schematic diagram of the structure at C in the present application; Figure 4

[0030] Figure 9 It is a schematic diagram of the prior art electric slip ring from natural air cooling to using vortex tube air cooling.

[0031] In the figure: 1, electric slip ring; 2, vortex tube; 3, shell; 4, filter screen; 5, pushing mechanism; 6, rotating mechanism; 7, communication pipe; 8, hot air outlet; 51, first support plate; 52, air cylinder; 53, air rod; 54, fixed plate; 55, sliding groove; 56, sliding block; 57, first guide groove; 58, first guide rod; 59, first hole; 510, baffle; 511, second hole; 61, sliding assembly; 62, swinging assembly; 611, connecting rod; 612, push plate; 613, guide hole; 614, pushing rod; 615, second guide rod; 621, nozzle; 622, sleeve; 623, second guide groove; 624, third guide rod; 625, push rod; 626, third hole; 627, rubber sealing gasket; 628, air supply pipe; 629, cooling pipe; 9, air outlet pipe. DETAILED DESCRIPTION ​​​

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0033] Please refer to Figures 1-9 The present application provides a technical solution: a high-speed electric slip ring cooling system based on vortex tube refrigeration, comprising an electric slip ring 1, a vortex tube 2 connected to one side of the electric slip ring 1, a connecting pipe 7 connected to the end of the vortex tube 2 away from the electric slip ring 1, an outer shell 3 connected to the end of the connecting pipe 7 away from the electric slip ring 1, a filter screen 4 arranged on the inner side of the outer shell 3, a hot air outlet 8 arranged on the outer side of the vortex tube 2, a push mechanism 5 arranged on one side of the outer shell 3, a rotating mechanism 6 arranged on the outer side of the push mechanism 5, and an air outlet pipe 9 connected to the side of the outer shell 3 away from the outer shell 3.

[0034] The rotating mechanism 6 comprises a sliding assembly 61 and a swinging assembly 62, and the swinging assembly 62 is arranged on the inner side of the sliding assembly 61.

[0035] The push mechanism 5 comprises a first support plate 51 fixedly connected to the outer side of the outer shell 3, a gas cylinder 52 fixedly connected to the outer side of the first support plate 51, a gas rod 53 fixedly connected to the output end of the gas cylinder 52, a fixed plate 54 fixedly connected to one end of the gas rod 53, and the filter screen 4 arranged at the end of the fixed plate 54 close to the vortex tube 2.

[0036] The inner side of the fixed plate 54 is provided with a sliding groove 55, the inner side of the sliding groove 55 is provided with a sliding block 56, the connection between the sliding block 56 and the filter screen 4 is fixed connection, a first guide groove 57 is formed on the inner side of the fixed plate 54, a first guide rod 58 fixedly connected with the sliding block 56 is arranged on the inner side of the first guide groove 57, a first hole 59 is formed on the side of the outer shell 3 close to the gas cylinder 52, a baffle 510 is arranged on the side of the outer shell 3 close to the gas cylinder 52, a second hole 511 for nesting is arranged on the inner side of the baffle 510, the width of the sliding groove 55 close to the gas cylinder 52 is greater than the width of the sliding groove 55 away from the gas cylinder 52, the outer side of the sliding block 56 is attached to the inner side of the sliding groove 55, a point a is arranged on the outer side of the end of the first guide groove 57 close to the vortex tube 2, a point b is arranged on the inner side of the end of the first guide groove 57 close to the vortex tube 2, a point c is arranged on the outer side of the end of the first guide groove 57 away from the vortex tube 2, and a point d is arranged on the inner side of the end of the first guide groove 57 away from the vortex tube 2, the horizontal height of the point a is higher than the horizontal height of the point b, and the horizontal height of the point c is lower than the horizontal height of the point d.

[0037] The sliding assembly 61 comprises a connecting rod 611 fixedly connected to the outside of the sliding block 56, one end of the connecting rod 611 is fixedly connected with a push plate 612, the inside of the push plate 612 is provided with a guide hole 613, the shell 3 is vertically and slidingly connected with a push rod 614 near one side of the electric slip ring 1, the inside of the guide hole 613 is provided with a second guide rod 615 fixedly connected with the push rod 614, the outer appearance structure of the guide hole 613 is wave-shaped, and the cooperation mode of the second guide rod 615 and the second guide rod 615 is gap cooperation.

[0038] The swinging assembly 62 comprises a nozzle 621 rotationally connected to the outside of the communication pipe 7, the outside of the nozzle 621 is fixedly connected with a sleeve 622, the inside of the sleeve 622 is provided with a second guide groove 623, the inside of the second guide groove 623 is provided with a third guide rod 624, the inside of the sleeve 622 is provided with a push rod 625 fixedly connected with the push rod 614, the shell 3 is provided with a third hole 626 for nesting the nozzle 621 near one side of the electric slip ring 1, the inside of the third hole 626 is connected with a rubber sealing gasket 627, the hot air outlet 8 is communicated with a blast pipe 628 of the nozzle 621, the outside of the blast pipe 628 is provided with a cooling pipe 629, the outer appearance structure of the second guide groove 623 is spiral-shaped, and the cooperation mode of the third guide rod 624 and the second guide groove 623 is gap cooperation, and the nozzle 621 is symmetrically provided with two about the central axis of the communication pipe 7.

[0039] When the external air enters the inside of the vortex pipe 2 from the filter screen 4, the air cylinder 52 drives the air rod 53, the fixed plate 54, the sliding block 56 and the filter screen 4 to reciprocate, because the first guide groove 57 is provided with an a point near the outside of one end of the vortex pipe 2, and is provided with a b point near the inside of one end of the vortex pipe 2, the first guide groove 57 is provided with a c point away from the outside of one end of the vortex pipe 2, and is provided with a d point away from the inside of one end of the vortex pipe 2, the horizontal height of the a point is higher than the horizontal height of the b point, and the horizontal height of the c point is lower than the horizontal height of the d point, so that when the first guide rod 58 moves to the a point and moves back, it can move to the upper inside of the first guide groove 57, and when the first guide rod 58 moves to the c point and moves back, it can move to the upper end inside of the first guide groove 57, so that the first guide rod 58 drives the filter screen 4 to reciprocate up and down and transversely, and when the vortex pipe 2 operates, the entering air will be divided into cold air and hot air, the hot air enters the blast pipe 628 and the nozzle 621 from the hot air outlet 8, and the filter screen 4 which has been filtered is blown in the reverse direction, the oil stains and water vapor in the inside of the filter screen 4 which has been filtered are blown out from the air outlet hole 9, the blockage of the filter screen 4 is reduced, and the cooling effect of the electric slip ring is improved.

[0040] The filter screen 4 is moved transversely during the cleaning process, the cleaned filter screen 4 is replaced at the position of the uncleaned filter screen 4, the vortex tube 2 does not need to be stopped for cleaning, and the electric slip ring does not need to be stopped, thereby prolonging the stable operation time of the electric slip ring and improving the work efficiency.

[0041] The hot air enters the air supply pipe 628 and the nozzle 621 from the hot air outlet 8, is cooled by the cooling pipe 629, and has reached the temperature range that the filter screen 4 can contact for a long time. The hot air contacts the water vapor and oil stains inside the filter screen 4, the water vapor and oil stains are heated, the condensation of the water vapor and oil stains on the inside of the filter screen 4 is reduced, and the oil stain discharge efficiency is improved.

[0042] The hot air is generated by the vortex tube during the refrigeration process and has been filtered, so that external air does not need to be heated and filtered again, energy is saved, and other filter screens are not polluted.

[0043] The water vapor and oil stains of the filter screen 4 are cleaned, the water vapor and oil stains enter the inside of the filter screen 4 for a short time when being cleaned, and do not have enough time to adhere, the adhesion time of the water vapor and oil stains is reduced, the adhesion force is not strong, and the oil stain discharge efficiency is improved.

[0044] The connecting rod 611 drives the push plate 612 and the guide hole 613 to move reciprocally, the guide hole 613 has a wave shape, the second guide rod 615 is in clearance fit with the second guide rod 615, the guide hole 613 drives the second guide rod 615 and the push rod 614 connected with the housing 3 and the third guide rod 624 vertically and slidably to move up and down, the second guide groove 623 has a spiral shape, the third guide rod 624 is in clearance fit with the second guide groove 623, the third guide rod 624 drives the nozzle 621 and the sleeve 622 to rotate, the nozzle 621 swings, the wind direction of the nozzle 621 changes, the wind diffusion range is larger, and the oil stain and gas discharge efficiency is improved.

[0045] It should be noted that, in the present document, the terms such as first and second, etc., are used merely to differentiate one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Also, the terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, so that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0046] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A high-speed electric slip ring cooling system based on vortex tube cooling, comprising an electric slip ring (1), a vortex tube (2) connected to one side of the electric slip ring (1), a connecting pipe (7) connected to the end of the vortex tube (2) away from the electric slip ring (1), a housing (3) connected to the end of the connecting pipe (7) away from the electric slip ring (1), a filter screen (4) disposed inside the housing (3), and a hot air outlet (8) disposed outside the vortex tube (2), characterized in that: A pushing mechanism (5) is provided on one side of the outer shell (3). The pushing mechanism (5) is used to drive the filter screen (4) to perform horizontal reciprocating motion and vertical reciprocating motion, so as to realize the online alternating cleaning of the filter screen (4) and complete the cleaning operation of the filter screen (4) without stopping the machine. A rotating mechanism (6) is provided on the outside of the pushing mechanism (5). The rotating mechanism (6) includes a sliding component (61) and a swing component (62). The swing component (62) is provided on the inside of the sliding component (61). The sliding component (61) is used to convert the reciprocating motion of the pushing mechanism (5) into a vertical driving motion, providing power to the swing component (62); the swing component (62) is used to receive the hot air generated by the vortex tube (2) and realize swing jet, expand the hot air jet range, and improve the discharge efficiency of oil and water vapor inside the filter screen (4). The outer casing (3) is connected to an air outlet pipe (9) on the side away from the electric slip ring (1).

2. The high-speed electric slip ring cooling system based on eddy current tube cooling according to claim 1, characterized in that: The pushing mechanism (5) includes a first support plate (51) fixedly connected to the outside of the outer shell (3). A cylinder (52) is fixedly connected to the outside of the first support plate (51). A rod (53) is fixedly connected to the output end of the cylinder (52). A fixed plate (54) is fixedly connected to one end of the rod (53). The filter screen (4) is located at one end of the fixed plate (54) near the vortex tube (2).

3. The high-speed electric slip ring cooling system based on eddy current tube cooling according to claim 2, characterized in that: The inner side of the fixed plate (54) is provided with a sliding groove (55), and the inner side of the sliding groove (55) is provided with a slider (56). The slider (56) is fixedly connected to the filter screen (4). The inner side of the fixed plate (54) is provided with a first guide groove (57). The inner side of the first guide groove (57) is provided with a first guide rod (58) fixedly connected to the slider (56). The outer shell (3) is provided with a first hole (59) on the side near the cylinder (52). The outer shell (3) is provided with a baffle (510) on the side near the cylinder (52). The inner side of the baffle (510) is provided with a second hole (511) for nesting.

4. A high-speed electric slip ring cooling system based on eddy current tube cooling according to claim 2, characterized in that: The width of the groove (55) near the cylinder (52) is greater than the width of the groove (55) away from the cylinder (52), and the outer side of the slider (56) is in contact with the inner side of the groove (55).

5. A high-speed electric slip ring cooling system based on eddy current tube cooling according to claim 2, characterized in that: Point a is provided on the outer side of the first guide groove (57) near the vortex tube (2), and point b is provided on the inner side of the first guide groove (57) near the vortex tube (2). Point c is provided on the outer side of the first guide groove (57) away from the vortex tube (2), and point d is provided on the inner side of the first guide groove (57) away from the vortex tube (2). The horizontal height of point a is higher than the horizontal height of point b, and the horizontal height of point c is lower than the horizontal height of point d.

6. A high-speed electric slip ring cooling system based on eddy current tube cooling according to claim 3, characterized in that: The sliding assembly (61) includes a connecting rod (611) fixedly connected to the outside of the slider (56). One end of the connecting rod (611) is fixedly connected to a push plate (612). The push plate (611) has a guide hole (613) inside. The outer shell (3) is vertically slidably connected to a push rod (614) on the side near the electric slip ring (1). A second guide rod (615) fixedly connected to the push rod (614) is provided inside the guide hole (613).

7. A high-speed electric slip ring cooling system based on eddy current tube cooling according to claim 6, characterized in that: The guide hole (613) has a wavy appearance, and the second guide rod (615) is fitted with the second guide rod (615) in a clearance fit.

8. A high-speed electric slip ring cooling system based on eddy current tube cooling according to claim 1, characterized in that: The swing assembly (62) includes a nozzle (621) rotatably connected to the outside of the connecting pipe (7). A sleeve (622) is fixedly connected to the outside of the nozzle (621). A second guide groove (623) is provided on the inner side of the sleeve (622). A third guide rod (624) is provided on the inner side of the second guide groove (623). A push rod (625) fixedly connected to the push rod (614) is provided on the inner side of the sleeve (622). A third hole (626) for nesting the nozzle (621) is provided on the side of the outer shell (3) near the electric slip ring (1). A rubber sealing gasket (627) is connected to the inner side of the third hole (626). The hot air outlet (8) is connected to an air supply pipe (628) connected to the nozzle (621). A cooling pipe (629) is provided on the outer side of the air supply pipe (628).

9. A high-speed electric slip ring cooling system based on eddy current tube refrigeration according to claim 8, characterized in that: The second guide groove (623) has a spiral shape, and the third guide rod (624) and the second guide groove (623) are fitted with a clearance fit.

10. A high-speed electric slip ring cooling system based on eddy current tube cooling according to claim 9, characterized in that: The nozzle (621) is arranged symmetrically about the central axis of the connecting pipe (7).

Images