CN103287857A - Biomass micro-positive-pressure pneumatic transmission system - Google Patents

Abstract

The invention discloses a biomass micro positive pressure pneumatic conveying system, which is composed of a feeding system, a fan, a conveying pipeline system, a discharge system, a tail gas treatment system and an automatic control system. The feeding system includes a quantitative feeding device, a material collecting device, a positive pressure air shutoff, an accelerator, an air induction pipe, and a return air processing pipeline. The conveying pipeline system includes straight pipelines, connecting flanges and several quick-opening doors and transparent observation windows distributed on the pipelines. Its advantages are that it can achieve smooth feeding with a high concentration ratio, and the power consumption is small. It also improves the service life of the air lock, the applicability of the conveying system and the durability of the pipeline, and facilitates the removal and maintenance of the pipeline. It can ensure no environmental pollution problems and a high degree of automation.

Description

A micro positive pressure pneumatic conveying system for biomass

technical field

The invention relates to a pneumatic conveying system in the mechanical field. The system is particularly suitable for conveying biomass and bulk and powder materials with low bulk density, specifically, a biomass micro positive pressure pneumatic conveying system.

Background technique

For a long period of time, for the handling of biomass bulk and powder materials with low bulk density, it is mostly carried out manually on a small scale, and mechanically assists on a large scale. Generally, woven bags are used for packaging, forklift loading and unloading, and transportation vehicles. way. This way of handling has high work intensity, harsh working environment, low work efficiency, and requires a lot of manpower and material resources. With the continuous expansion of the production capacity of enterprises in recent years, this handling method obviously cannot meet the needs of large-scale production.

The conveying method of auger and scraper conveyor is also used in short-distance conveying of several meters to tens of meters. However, these methods are heavy equipment, occupy a large space, have poor environmental adaptability, heavy maintenance workload, and are easy to pollute the environment. If they are used for long-distance transportation, they are not only costly but also difficult to implement.

Micro positive pressure pneumatic conveying is a technology that uses wind energy to convey materials. Due to the characteristics of high conveying efficiency, easy automation, closed conveying process, no leakage of materials, less pollution, long-distance conveying in complex environments, flexible configuration, small space and site, etc., micro positive pressure pneumatic conveying technology There are many applications in the transportation of powder and bulk materials in metallurgy, grain, chemical industry, electric power and other industries. However, the micro-positive pressure pneumatic conveying system commonly used in the market is limited by feeding and other problems, such as low conveying concentration, serious material breaking problem, high energy consumption, low degree of automation, and serious pipeline wear.

In the grain processing industry, the flour transportation of modern flour processing plants also adopts the micro positive pressure transportation method. In the husking link in the rice processing process, the rice husk is often separated by air flow and blown into the rice husk temporary storage bin. When conveying flour, it is easy to convey because of its uniform texture and short conveying distance. Although the energy consumption is high, it can still meet the needs of production. In the husking process of rice processing, blowing the rice husks to the rice husk temporary storage bin through airflow is actually an application of micro positive pressure pneumatic conveying, but there are also problems such as low conveying concentration (0.5-2) and high energy consumption per unit conveying volume, because of this The transportation distance is very short in the environment, and the transportation is not the main task of the process, so there are not many studies on related issues, and no improved methods have been published.

Based on the above, on the basis of the existing flour and rice husk pneumatic conveying technology, the present invention is aimed at the fact that biomass is mostly production and processing waste (such as crop shells, cut straw, branches and leaves and their extruded products, etc.) , complex composition, large shape difference, low bulk density and other characteristics, invented a set of pneumatic conveying system suitable for biomass transportation, low energy consumption, high degree of automation, compact structure, long service life, easy installation and maintenance, and for After research and analysis, program demonstration, system design and prototype system development and engineering application assessment work, the present invention, namely the biomass micro-positive pressure pneumatic conveying system, was formed.

Contents of the invention

The purpose of the present invention is to provide a set of pneumatic conveying system suitable for biomass transportation, low energy consumption, high degree of automation, compact structure, long service life, easy installation and maintenance, the specific technical solution is:

A biomass micro-positive pressure pneumatic conveying system is composed of a feeding system, a fan, a conveying pipeline system, a discharge system, a tail gas treatment system and an automatic control system, and is characterized in that:

a. The feeding system has a quantitative feeding device 2, a material collecting device 3, an accelerator 5, an air induction pipe 8 and a return air treatment pipeline 9;

b. The conveying pipeline system 7 has straight pipes, bent pipes, connecting flanges, some quick-opening doors and transparent observation windows distributed on the pipelines;

c. The described unloading system includes a cyclone separator 10, an unloading air lock 11, a hopper or a silo 12;

d. The automatic control system includes a sequence control device for starting and stopping the system, a feed rate control device, a material level detection alarm or control device, a motor overload protection device, and a display and operation interface device.

Preferably, the feeding system is also provided with a positive pressure air lock 4 .

Preferably, both the positive pressure air locker 4 and the discharge air locker 11 are provided with adjustable blades 21 , wear-resistant lining plates 23 and anti-seize brackets 22 .

Preferably, the air induction pipe 8 is used to induce air from the side of the air pipe between the fan 6 and the accelerator 5 to the lower chamber of the positive pressure air lock 4 or near the upper end of the accelerator 5 feed hopper.

Preferably, the return air processing pipeline 9, specifically, draws air from an appropriate part of the feeding system in front of the positive pressure air lock 4 to the air inlet of the fan through the pipeline and the dust removal device.

Preferably, for occasions where multi-point feeding or multi-point discharge is required, the delivery pipeline system further includes a two-way valve 13 .

Preferably, a tail gas treatment system is also included, and the tail gas treatment system includes a tail gas discharge pipe 14 and a dust collector 15 .

Preferably, the automatic control system in the whole biomass positive pressure conveying system is automatically controlled, monitored and coordinated in real time by PLC or single-chip microcomputer.

Preferably, the quick-opening door includes a hinge 24 , a seal 25 , a quick-opening door panel 26 and a lock catch 27 .

The quantitative feeding device is specifically a device for realizing quantitative feeding through the opening and closing degree of the electric gate, or the frequency conversion speed regulation of the auger, or the vibrating feeder.

The material collecting device is specifically a multi-entrance screw conveyor, a scraper conveyor or other equipment used to centrally send materials into positive pressure air locks or accelerators.

The return air processing pipeline described above is specifically to draw air from a suitable part of the feeding system before the positive pressure air shutoff to the air inlet of the fan through the pipeline and the dust removal device.

The fan mentioned above is specifically a Roots fan or a high- and medium-pressure centrifugal fan; since the Roots fan has an approximate constant flow characteristic, it is preferably used in long-distance transportation.

The straight pipe, specifically the straight section of the pipe made of seamless steel pipe or other wear-resistant pipe, is welded to a required length by standard flanges, collars, spiral connections or butt welding.

The elbow is designed for turning the pipeline, specifically, it is an elbow made of seamless steel pipes or spliced with ceramic composite pipes.

The dust collector can be a bag filter, a spray dust collector, a volumetric dust collector (ash chamber) or other dust removal devices.

The material level detection of the automatic control system is realized by using rotary resistance type, capacitive type, light induction type or sonar type material level sensor.

The detection points of the automatic control system include: motors used by each equipment of the system, and material level sensors arranged at various parts.

Technical scheme of the present invention can be realized in the following ways:

The feeding hopper or the bottom of the silo is connected to the quantitative feeding device, the quantitative feeding device is connected to the collecting device (for multi-point feeding), the collecting device is connected to the positive pressure air shutoff device, and the positive pressure air shutoff device is connected to the accelerator (in some occasions, it may not be used). Use a positive pressure airlock, at this time the dosing device is directly accelerated). The inlet end of the accelerator is connected to the fan, and the air outlet end is connected to the head end of the conveying pipeline. From the side of the air duct between the fan and the accelerator, use an air duct (such as a hose) to guide the air to the lower chamber of the positive pressure air lock (in some occasions, the positive pressure air lock may not be used, and at this time the air is induced to the quantitative feeding device. end or near the upper end of the accelerator feed hopper). From the appropriate part of the feeding system, the air is drawn to the air inlet of the fan through the pipeline and the dust removal device. According to the conveying environment, the conveying pipeline is composed of a straight pipe or a combination of a straight pipe and an elbow, and is connected by flanges, collars, spirals or butt welding. The end of the conveying pipeline is connected to the unloading system, specifically the air inlet of the cyclone separator connected to the unloading system, the cyclone separator is connected to the unloading air shutoff device, and the unloading air shutoff device is installed on the upper part of the receiving hopper or the receiving bin. For a simple system, the end of the conveying pipeline can be directly connected to the receiving room or open field, or through a similar cyclone separator or settling chamber to the receiving room or open field. The air outlet of the cyclone separator (if used) of the unloading system is connected to the exhaust gas treatment system through a pipe.

Near both ends of the conveying pipeline and appropriate parts, connect transparent observation windows in series and install quick-opening inspection doors.

The automatic control system uses PLC or single-chip microcomputer to control the start or stop of each motor according to the process requirements, and detects the real-time signals (fault, material level, speed, etc.) of each motor and material level sensors.

The general process route of the present invention is shown in accompanying drawing 4. For a more complex (such as multi-row warehouse feeding) long-distance conveying system, more than two feeding systems can also be used to feed the conveying pipeline occasionally, and a two-way valve (three-way valve) can be used to switch.

Working process of the present invention is as follows:

During normal operation, the material is fed to the collecting device through the quantitative feeding device, and the material is fed to the positive pressure air lock by the material collecting device, and the positive pressure air lock guides the material to the accelerator. After being accelerated by the accelerator, the material is mixed with the jet airflow at the lower part of the accelerator and sent into the conveying pipeline to enter the conveying process. The air is drawn from the air pipe between the fan and the accelerator to the lower chamber of the positive pressure air shutoff, which increases the pressure from the lower chamber of the air shutoff to the upper part of the accelerator, and drives the material to accelerate. The return air of the positive pressure air lock is guided from the appropriate part of the feeding system to the air inlet of the fan through the pipeline and the dust removal device, which avoids the environmental pollution caused by the overflow of the positive pressure air lock. After conveying to the conveying destination, the mixture of airflow and material enters the cyclone separator for separation. The separated material spins down and is discharged to the receiving hopper or the receiving bin through the discharge air lock. The separated tail gas goes up from the middle pipe of the cyclone separator to the tail gas discharge pipe, and the tail gas discharge pipe sends the tail gas to the tail gas treatment system for treatment and discharge.

For the multi-point feeding system, the switch between the feeding points can be realized through the electric (pneumatic) two-way valve or similar valve; for the multi-point unloading system, through the electric (pneumatic) two-way valve or similar valve, Switching between unloading points can be realized.

The general start-up sequence of the system of the present invention:

Exhaust gas treatment system—→unloading air lock——→fan——→positive pressure air lock—→collecting device——→quantitative feeding device

The general shutdown sequence of the system of the present invention:

Quantitative feeding device——→collecting device——→positive pressure air lock——→fan——→discharging air lock——→exhaust gas treatment system

Unexpected handling and control method of the present invention:

When the power supply is interrupted unexpectedly or the fan is shut down unexpectedly, it may cause the biomass to settle and accumulate in the pipeline, and the pipeline may be blocked when the machine is turned on again, causing the system to fail to work normally. For this reason, the present invention is provided with quick-opening door at the suitable position of accelerator, pipeline. Open the quick-opening doors in an appropriate order, supplemented by a fan to blow air, which can facilitate the removal of pipeline blockage.

When the material level of the receiving bin or hopper is higher than the high level, the system will alarm and stop automatically.

The control system of the present invention has interlocking and fault handling functions. When the system tries to start a certain device against the startup sequence (in manual mode), the startup will be locked; It will alarm; when the failure hinders the system transportation, it will stop automatically in sequence; when the failure is serious, it will stop all in an instant.

The advantages of this biomass micro positive pressure conveying system are:

a. The supporting feeding system is used, including feeding quantitative device, positive pressure air shut-off device and biomass micro-positive pressure conveying accelerator, which can realize smooth feeding with a higher concentration ratio, and solve the problem of micro-positive pressure pneumatic conveying system. Difficulty in feeding materials.

b. An anti-jam bracket is installed on the side of the inlet of the positive pressure air locker and the discharge air locker, which effectively solves the problem that the air locker is easily stuck by impurities; Replacement wear-resistant bushings, combined with radially adjustable blades that can compensate for wear, improve the service life of the air shutoff.

c. The delivery pipeline uses seamless steel pipes as straight pipes, and seamless steel pipes are used for large-radius cold-drawn forming or steel-ceramic composite pipes to make bent pipes, which improves the durability of the pipelines; equipped with transparent observation windows and quick-opening maintenance doors, The visibility of the transportation situation is improved, and the blockage removal and maintenance of the pipeline are facilitated; for the transportation that requires parallel flow or divergent flow, the present invention independently develops an electric (pneumatic) two-way valve, which can conveniently realize the switching of the transmission line.

d. The transportation pipeline used takes up little space, the line layout is simple and flexible, and the site adaptability is good.

e. The perfect and flexible unloading and exhaust gas treatment system, while adapting to the conditions of the transportation site, ensures no environmental pollution.

f. From the appropriate part of the feeding system, the air is drawn to the air inlet of the fan through the pipeline and the dust removal device, which well solves the environmental pollution problem of the return air of the positive pressure air shutoff device during the slight positive pressure pneumatic conveying.

g. Due to the high conveying concentration ratio (4-8), the diameter of the pipeline used is small, and the power consumption is also small, which can save energy by more than 50% compared with other conveying systems.

h. The whole system adopts PLC automatic control system, which has a high degree of automation and can realize one-button operation, which greatly saves labor costs.

i. Due to the above-mentioned advantages of the present invention, wheat bran, chaff, raw grain inclusions, etc., which were mostly used as processing waste before, can be collected, transported and reused at low cost (such as as renewable energy, further deep processing, etc.), not only in line with National energy conservation and emission reduction policies can also create certain economic benefits for enterprises.

j. The present invention can be directly used in the transportation of flour and powder and bulk materials in other fields.

Description of drawings

Fig. 1 is a system composition structural diagram of one of the present invention;

Fig. 2 is a structural diagram of the main part of the feeding system of the present invention;

Fig. 3 is a longitudinal sectional view of the pipeline quick-opening door of the present invention;

Fig. 4 is a cross-sectional view of the pipeline quick-opening door of the present invention;

Fig. 5 is a top view of the pipeline quick-opening door of the present invention;

Figure 6 is a general process roadmap of the system.

Among them: 1 Material bin 2 Feeding and dosing device 3 Material collecting device 4 Positive pressure air shutoff device 5 Accelerator 6 Fan 7 Conveying pipeline system 8 Air induction pipe 9 Return air treatment pipeline 10 Centrifugal cyclone separator accepts material 11 Unloading Material air locker 12 Hopper 13 Two-way valve 14 Exhaust gas discharge pipe 15 Dust collector 16 Air inlet 17 Air inlet 18 Material guide plate 19 Injection nozzle 20 Throat pipe 21 Adjustable leaf blade 22 Anti-seize bracket 23 Wear-resistant lining plate 24 Hinge 25 seal 26 quick door panel 27 lock.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1-6, the biomass micro-positive pressure conveying system is supplied by the material bin 1, the material bin 1 is connected to the quantitative feeding device 2, and the quantitative feeding device 2 is connected to the collecting device 3. When multi-point feeding, the material is collected The device has a corresponding number of feed ports, the collecting device 3 is connected to the positive pressure air shutoff 4, the lower outlet of the positive pressure air shutoff 4 is connected to the upper opening of the accelerator 5, and the air outlet of the fan 6 is connected to the air inlet of the accelerator 5. The air pipe between the blower fan 6 and the accelerator is provided with an air inlet 16, and the end of the lower chamber of the positive pressure air shutoff device 4 is provided with an air inlet 17, and the air inlet 16 and the air inlet 17 are connected with a thinner pipe (this example is a hose) 8; A return air treatment pipeline 9 is provided from the collecting device 3 to the air inlet of the fan 6 . The outlet of the accelerator 5 is connected to the delivery pipeline system 7, and the delivery pipeline system 7 is connected to the two-way valve 13 according to the complexity of the system. The end of the conveying pipeline system 7 is connected to the inlet of the centrifugal cyclone separator 10 , the bottom of the cyclone separator 10 is connected to the unloading air lock 11 , and the air outlet of the cyclone separator 10 is connected to the tail gas discharge pipe 14 . The tail gas discharge pipe 14 is connected to the tail gas treatment system 15 . The unloading air lock 11 is located on the upper part of the hopper or the silo. The control system can have separate control cabinets near the feeding system and unloading system or only one control cabinet at a convenient position for operation. Material level sensors can be installed at appropriate parts of the hopper, silo and feeding system. The control system can be controlled in accordance with the program. In addition to the start and stop of the machine, it also detects the working condition of the motor and the material level in real time, and handles it accordingly.

The adjustable blade blade 21 cuts into the side fortification card support 22 at the feed port of the positive pressure air lock and the discharge air lock, and a wear-resistant lining plate 23 is set on the positive pressure air lock and the discharge air lock inner wall.

When the system is working normally, the quantitative feeding device 2 feeds the material to the collecting device 3, and the collecting device 3 feeds the material to the positive pressure air lock 4, and the positive pressure air lock 4 guides the material to the accelerator 5. After being accelerated by the accelerator 5, the material is mixed with the jet flow at the lower part of the accelerator 5 and sent into the conveying pipeline system 7 to enter the conveying process. From the air pipe between the fan 6 and the accelerator 5, the air is introduced to the lower chamber of the positive pressure air shutoff device 4, which increases the pressure between the lower chamber of the positive pressure air shutoff device 4 and the upper part of the accelerator 5, and drives the induction of materials on the material guide plate 18. Down, the accelerated flow is towards the front of the nozzle of the accelerator. Since the direction of the accelerated flow tends to be consistent with the direction of the jet stream of the nozzle, the resistance of the jetting material is greatly reduced, and smooth feeding is realized. The return air of the positive pressure air lock 4 is drawn from the appropriate part of the feeding system to the air inlet of the fan 6 through the return air processing pipeline 9, thereby avoiding the environmental pollution problem caused by the overflow of the return air of the positive pressure air lock 4. After the transportation reaches the destination, the mixture of airflow and material enters the cyclone separator 10 to realize separation. The separated material spins down and is discharged to the receiving hopper or the receiving bin 12 through the discharge locker 11 . The separated tail gas goes up from the middle pipe of the cyclone separator 10 to the tail gas discharge pipe 14, and the tail gas discharge pipe 14 sends the tail gas to the tail gas treatment system 15 for treatment and discharge.

For the multi-point feeding system, the switch between the feeding points can be realized through the electric (pneumatic) two-way valve 13 or similar valve; for the multi-point unloading system, the electric (pneumatic) two-way valve 13 or similar Valves for switching between discharge points.

The specific operation sequence of the conveying pipeline blockage removal of the conveying pipeline system 7 is: open the lock 27, open the quick-opening door panel 26 downward around the hinge 24, open all the quick-opening doors on the conveying pipeline in turn, start the fan, and when the conveying pipeline 7 is the first After the quick-opening door material is emptied, turn off the fan, close the first quick-opening door of the conveying pipeline, pay attention to keep the seal 25 intact, and replace it if necessary; start the fan again, and turn off the fan when the second quick-opening door in the first part of the conveying pipeline is emptied. Open the door at the front of the pipeline, and so on, until all the pipelines are cleared.

When the material level of receiving bin or hopper 12 is higher than the high material level, the system will alarm and stop automatically.

When the system tries to start a certain device against the startup sequence (in manual mode), the startup will be locked; It will alarm; when the failure hinders the system transportation, it will stop automatically in sequence; when the failure is serious, it will stop all in an instant. The advantages of this biomass micro positive pressure conveying system are:

a. The supporting feeding system is used, including feeding quantitative device, positive pressure air shut-off device and biomass micro-positive pressure conveying accelerator, which can realize smooth feeding with a higher concentration ratio, and solve the problem of micro-positive pressure pneumatic conveying system. Difficulty in feeding materials.

b. An anti-jam bracket is installed on the side of the inlet of the positive pressure air locker and the discharge air locker, which effectively solves the problem that the air locker is easily stuck by impurities; Replacement wear-resistant bushings, combined with radially adjustable blades that can compensate for wear, improve the service life of the air shutoff.

c. The delivery pipeline uses seamless steel pipes as straight pipes, and seamless steel pipes are used for large-radius cold-drawn forming or steel-ceramic composite pipes to make bent pipes, which improves the durability of the pipelines; equipped with transparent observation windows and quick-opening maintenance doors, The visibility of the transportation situation is improved, and the blockage removal and maintenance of the pipeline are facilitated; for the transportation that requires parallel flow or divergent flow, the present invention independently develops an electric (pneumatic) two-way valve, which can conveniently realize the switching of the transmission line.

d. The transportation pipeline used takes up little space, the line layout is simple and flexible, and the site adaptability is good.

e. The perfect and flexible unloading and exhaust gas treatment system, while adapting to the conditions of the transportation site, ensures no environmental pollution.

f. From the appropriate part of the feeding system, the air is drawn to the air inlet of the fan through the pipeline and the dust removal device, which well solves the environmental pollution problem of the return air of the positive pressure air shutoff device during the slight positive pressure pneumatic conveying.

g. Due to the high conveying concentration ratio (4-8), the diameter of the pipeline used is small, and the power consumption is also small, which can save energy by more than 50% compared with other conveying systems.

h. The whole system adopts PLC automatic control system, which has a high degree of automation and can realize one-button operation, which greatly saves labor costs.

i. Due to the above-mentioned advantages of the present invention, wheat bran, chaff, raw grain inclusions, etc., which were mostly used as processing waste before, can be collected, transported and reused at low cost (such as as renewable energy, further deep processing, etc.), not only in line with National energy conservation and emission reduction policies can also create certain economic benefits for enterprises.

j. The present invention can be directly used in the transportation of flour and powder and bulk materials in other fields.

It can be known from common technical knowledge that the present invention can be realized through other embodiments without departing from its spirit or essential features. Accordingly, the above-disclosed embodiments are, in all respects, illustrative and not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are embraced by the present invention.

Claims (9)

1. A biomass micro-positive pressure pneumatic conveying system is composed of a feeding system, a blower fan, a conveying pipeline system, a discharge system, a tail gas treatment system and an automatic control system, and is characterized in that: a. The described feeding system has a quantitative feeding device (2), a material collecting device (3), an accelerator (5), an air induction pipe (8) and a return air processing pipeline (9); b. The conveying pipeline system (7) has straight pipes, curved pipes, connecting flanges, some quick-opening doors and transparent observation windows distributed on the pipelines; c. The described unloading system includes a cyclone separator (10), an unloading air lock (11), a hopper or a silo (12); d. The automatic control system includes a sequence control device for starting and stopping the system, a feed rate control device, a material level detection alarm or control device, a motor overload protection device, and a display and operation interface device. 2. The biomass micro positive pressure pneumatic conveying system according to claim 1, characterized in that, said feeding system is also provided with a positive pressure air lock (4). 3. The micro positive pressure pneumatic conveying system for biomass as claimed in claim 2, characterized in that, the air duct (8) from the blower fan (6) to the side of the accelerator (5) uses a soft The pipe induces wind to the lower chamber of the positive pressure air shutoff device (4) or near the upper end of the accelerator (5) feed hopper. 4. The micro positive pressure pneumatic conveying system for biomass as claimed in claim 1 and claim 2, characterized in that, the positive pressure air lock (4) and the discharge air lock (11) are all equipped with Adjust the blade blade (21), the wear-resistant lining plate (23) and the anti-seize bracket (22). 5. The biomass micro positive pressure pneumatic conveying system according to claim 1, characterized in that, the conveying pipeline system further comprises a two-way valve (13). 6. The biomass micro-positive pressure pneumatic conveying system according to claim 1, further comprising a tail gas treatment system comprising a tail gas discharge pipe (14) and a dust collector (15). 7. The biomass micro-positive pressure pneumatic conveying system as claimed in claim 1, wherein the automatic control system in the whole biomass micro-positive pressure conveying system is automatically controlled, real-time monitored and coordinated by a PLC or a single-chip microcomputer. 8. The biomass micro-positive pressure pneumatic conveying system according to claim 1, characterized in that, the quick-opening door includes a hinge (24), a seal (25), a quick-opening door panel (26) and a lock (27) . 9. The biomass micro-positive pressure pneumatic conveying system as claimed in claim 1, characterized in that, the return air treatment pipeline (9) includes an air induction pipe from the feeding system, a dust chamber and a blower fan Air intake near the air inlet.

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