CN111517310A

CN111517310A - Popped device of continuous microwave of graphite alkene

Info

Publication number: CN111517310A
Application number: CN202010339326.2A
Authority: CN
Inventors: 杨杰; 江兆潭; 王卫东; 轩海成; 高强
Original assignee: Shandong Woxi New Material Technology Co ltd
Current assignee: Shandong Woxi New Material Technology Co ltd
Priority date: 2020-04-26
Filing date: 2020-04-26
Publication date: 2020-08-11
Anticipated expiration: 2040-04-26
Also published as: CN111517310B

Abstract

The invention discloses a continuous microwave puffing device for graphene, and relates to the technical field of graphene processing. According to the invention, high-temperature gas generated during material puffing is utilized, so that a heat preservation effect is achieved on the puffing furnace, the problem of heat loss caused by large temperature difference inside and outside the puffing furnace is avoided, the heat of the puffed high-temperature material can be recycled, the recycled heat is used for preheating the material to be puffed, and the double-sided effect is achieved, so that the processing effect of the graphene material is better, and meanwhile, the waste of heat is reduced.

Description

Popped device of continuous microwave of graphite alkene

Technical Field

The invention relates to the technical field of graphene processing, in particular to a graphene continuous microwave puffing device.

Background

The preparation method of the graphene mainly comprises a physical method and a chemical method, wherein the physical method comprises a mechanical stripping method and an epitaxial growth method, and the chemical method comprises a chemical vapor deposition method and a redox method; in order to realize large-scale industrialization of graphene production, the most widely used preparation process at present is still an oxidation-thermal reduction method. The pre-puffing treatment of the graphene oxide in the existing production process mainly comprises a high-temperature resistance furnace or microwave puffing equipment, but when the graphene is subjected to microwave puffing treatment, heat in the puffing furnace is easy to lose, the puffing effect is easy to influence, and the graphene material is not perfect in the pretreatment when entering the puffing furnace, so that the waste of resources is easily increased, and in the puffing process, a large amount of graphene dust and harmful substances are contained in the generated high-temperature gas, and the influence on the air environment is easily caused. Therefore, the technical personnel in the field provide a graphene continuous microwave puffing device to solve the problems in the background technology.

Disclosure of Invention

The invention aims to provide a graphene continuous microwave puffing device to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a graphene continuous microwave puffing device comprises a puffing furnace, wherein a material receiving bin is arranged at the lower end of the puffing furnace, a furnace cover is arranged at the upper end of the puffing furnace, an exhaust pipe is arranged on the upper surface of the furnace cover, a feed hopper is arranged at one end of the puffing furnace, a control panel is arranged on one side face of the lower end of the feed hopper, a driving motor is arranged at the bottom end of the feed hopper, a casing is arranged at one end of the driving motor, the other end of the puffing furnace is connected with a communicating pipe, the puffing furnace is connected with a bag-type dust collector through the communicating pipe, a secondary purifying box is arranged on one side of the bag-type dust collector, a spiral conveying roller is arranged in the puffing furnace, a discharging groove is arranged below one end, positioned on the spiral conveying roller, in the puffing furnace, a heat preservation cavity is arranged in the puffing furnace, a heater, an inner hopper is arranged inside the feeding hopper, a preheating cavity is arranged between the feeding hopper and the inner hopper, and a second circulating pipe is arranged inside the preheating cavity.

As a further scheme of the invention: the material receiving bin is arranged on the lower end of the side face of the material receiving bin, one end of the material receiving bin is communicated with a material receiving bin inside the puffing furnace, and the other end of the material receiving bin is communicated with the puffing furnace.

As a still further scheme of the invention: the inside that driving motor's one end was located the casing is provided with the belt roller, and the belt roller surface has cup jointed the belt, the one end of spiral conveying roller is passed through the belt and the belt roller is rotated with driving motor's output and is connected, and the other end of spiral conveying roller rotates with the inner wall of puffing stove to be connected.

As a still further scheme of the invention: four gas vents have been seted up to the surperficial equidistance of bell, and one side that the upper surface of bell is close to the gas vent corresponds heat preservation chamber department and has seted up the air inlet, the one end of blast pipe is linked together through gas vent and expansion furnace's inside, and the other end of blast pipe is linked together through the one end of air inlet with first circulating pipe, the other end of first circulating pipe is linked together through communicating pipe and sack cleaner, first circulating pipe encircles and sets up in the inside of heat preservation chamber.

As a still further scheme of the invention: the inside bottom of interior fill is provided with the stirring roller, the inside that the one end of stirring roller is located the casing is provided with agitator motor, the trailing flank of feeder hopper runs through there is the return pipe, and the leading flank of feeder hopper runs through there is the conveyer pipe, the one end of return pipe is connected with the compression pump, the inside that connects the feed bin is provided with the end storehouse, the U-shaped pipe has been laid to the bottom surface in end storehouse, be provided with the evaporimeter on the U-shaped pipe.

As a still further scheme of the invention: the second circulating pipe is located inside the preheating cavity and surrounds the outer side wall of the inner hopper, one end of the second circulating pipe is communicated with the loop pipe, the other end of the second circulating pipe is communicated with the conveying pipe, one end of the U-shaped pipe is communicated with the other end of the loop pipe through the compression pump, and the other end of the U-shaped pipe is communicated with the other end of the conveying pipe.

As a still further scheme of the invention: the second grade purifying box divide into about two-layer, the inside water tank that is provided with of lower floor of second grade purifying box, the upper surface middle part of water tank is provided with the connecting pipe, the inside water receiving tank that is provided with in upper strata of second grade purifying box, the inside top of upper strata of second grade purifying box corresponds water receiving tank department and is provided with and drenches the dish, the top correspondence of second grade purifying box drenches the middle part of dish and is provided with the water inlet, and the upper end side of second grade purifying box is provided with the outlet duct, the another side lower extreme of second grade purifying box is provided with the.

As a still further scheme of the invention: the one end of intake pipe is linked together with the upper end of sack cleaner, and the other end of intake pipe runs through the inside bottom that the second grade purifying box extended to the water tank, the inside notes of water tank has water, the water tank is linked together through the connecting pipe with the water receiving tank, the inside of drenching the dish is hollow structure, and drenches the lower surface distribution of dish and have a plurality of to drench the orifice.

Compared with the prior art, the invention has the beneficial effects that: the continuous microwave puffing device for graphene, which is designed by the invention, can utilize high-temperature gas generated in puffing of materials during actual operation, thereby playing a role in heat preservation for the puffing furnace, not only avoiding the problem of heat loss caused by large temperature difference inside and outside the puffing furnace, but also improving the puffing effect of the graphene materials, further, cooling the puffed high-temperature materials, recycling the high-temperature heat during cooling, transferring the high-temperature heat into the feed hopper, preheating the incoming graphene materials, thereby not only realizing the cooling of the puffed high-temperature materials, but also preheating the materials to be puffed, realizing double-sided effect, leading the processing effect of the graphene materials to be better, simultaneously reducing the waste of heat, and realizing the function of the secondary purification box, and carrying out secondary purification on the discharged gas, the method avoids harmful dust or impurities in the gas from being discharged into the air to influence the environmental quality or harm the human health, and the design has the advantages of simple and convenient operation, high energy recovery and utilization rate and ensured puffing effect of the material.

Drawings

Fig. 1 is a schematic structural diagram of a graphene continuous microwave puffing apparatus;

fig. 2 is a schematic structural diagram of a puffing furnace in a graphene continuous microwave puffing device;

FIG. 3 is a schematic view showing the installation of a first circulation pipe in the continuous microwave graphene expansion apparatus;

FIG. 4 is a schematic diagram of a feed hopper and a second circulation pipe in a graphene continuous microwave puffing apparatus;

fig. 5 is a schematic structural diagram of a secondary purification box in a graphene continuous microwave puffing device.

In the figure: 1. a bulking furnace; 2. an exhaust pipe; 3. a feed hopper; 4. a housing; 5. a material receiving bin; 6. a discharge port; 7. a secondary purification box; 8. a communicating pipe; 9. a bag-type dust collector; 10. a furnace cover; 11. a control panel; 12. a drive motor; 13. a discharging pipe; 14. an exhaust port; 15. an air inlet; 16. a heat preservation cavity; 17. a discharging groove; 18. a spiral conveying roller; 19. a heater; 20. a first circulation pipe; 21. a bottom bin; 31. a stirring roller; 32. an inner bucket; 33. a preheating chamber; 34. a loop pipe; 35. a compression pump; 36. a second circulation pipe; 37. a delivery pipe; 38. a U-shaped tube; 39. an evaporator; 71. a water tank; 72. a connecting pipe; 73. a water receiving tank; 74. spraying a plate; 75. a water inlet; 76. an air outlet pipe; 77. an air inlet pipe.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 to 5, in the embodiment of the present invention, a graphene continuous microwave puffing apparatus includes a puffing furnace 1, a material receiving bin 5 is disposed at a lower end of the puffing furnace 1, a furnace cover 10 is disposed at an upper end of the puffing furnace 1, an exhaust pipe 2 is disposed on an upper surface of the furnace cover 10, a feed hopper 3 is disposed at one end of the puffing furnace 1, a control panel 11 is disposed on a side surface of a lower end of the feed hopper 3, a driving motor 12 (model MCA17N23-RS0B0) is disposed at a bottom end of the feed hopper 3, a housing 4 is disposed at one end of the driving motor 12, a communicating pipe 8 is connected to the other end of the puffing furnace 1, the puffing furnace 1 is connected to a bag-type dust collector 9 through the communicating pipe 8, a secondary purification box 7 is disposed at one side of the bag-type dust collector 9, a spiral conveying roller 18 is disposed, the inside of expansion furnace 1 has been seted up heat preservation chamber 16, and the inside of heat preservation chamber 16 is provided with heater 19, and the heating method of this heater 19 adopts current microwave heating method, and the outside that the inside of heat preservation chamber 16 is located heater 19 is provided with first circulating pipe 20, and the inside of feeder hopper 3 is provided with interior fill 32, and is provided with preheating chamber 33 between feeder hopper 3 and the interior fill 32, and the inside of preheating chamber 33 is provided with second circulating pipe 36.

The material bin 5 is connected with the unloading pipe 13 between stove 1 and the material receiving bin 5, a side lower extreme that connects the feed bin 5 is provided with discharge gate 6, the one end of unloading pipe 13 is linked together with the inside lower chute 17 of stove 1 that expands, and the other end of unloading pipe 13 is linked together with the material receiving bin 5, the inside that the one end of driving motor 12 is located casing 4 is provided with the belt roller, and the belt roller surface has cup jointed the belt, the one end of spiral conveying roller 18 is passed through the belt and the belt roller is rotated with the output of driving motor 12 and is connected, and the other end of spiral conveying roller 18 is rotated with the inner wall of stove 1 that expands and is connected, through the effect of spiral conveying roller 18, conveniently carry under silo 17 department with the material after popped, the cooperation of trough 17 and unloading pipe 13 under the rethread, arrange in connecing the material bin 5, connect the.

Four exhaust ports 14 are equidistantly formed in the surface of the furnace cover 10, an air inlet 15 is formed in one side, close to the exhaust port 14, of the upper surface of the furnace cover 10, corresponding to the heat preservation cavity 16, an air inlet 15 is formed in one end of the exhaust pipe 2, communicated with the interior of the expansion furnace 1 through the exhaust port 14, the other end of the exhaust pipe 2 is communicated with one end of a first circulating pipe 20 through the air inlet 15, the other end of the first circulating pipe 20 is communicated with a bag-type dust collector 9 through a communicating pipe 8, the first circulating pipe 20 is arranged in the heat preservation cavity 16 in a surrounding mode, when the furnace cover 10 is in sealing connection with the expansion furnace 1 during work, and the interior of the expansion furnace 1 is not communicated with the heat preservation cavity 16, therefore when graphene is subjected to expansion treatment in the expansion furnace 1, generated hot air is discharged into the exhaust pipe 2 through the exhaust port 14 and then discharged into the, and first circulating pipe 20 is evenly around inside heat preservation chamber 16, consequently when the hot-air enters into first circulating pipe 20, the heat transfer takes place for the inside cold air in high temperature hot-air and heat preservation chamber 16, thereby can make the inside air of heat preservation chamber 16 heat up, realize the heat preservation effect to expansion furnace 1 from this, in order to prevent at the popped in-process, the furnace body heat runs off, lead to the inside temperature of expansion furnace 1 not high enough and influence popped effect, the inside high temperature gas of first circulating pipe 20 is after the heat transfer, arrange into communicating pipe 8 by its other end, arrange into sack cleaner 9 by communicating pipe 8 again.

The bottom end of the inner hopper 32 is provided with a stirring roller 31, one end of the stirring roller 31 is positioned in the casing 4 and is provided with a stirring motor, the rear side surface of the feed hopper 3 is penetrated with a loop pipe 34, the front side surface of the feed hopper 3 is penetrated with a delivery pipe 37, one end of the loop pipe 34 is connected with a compression pump 35 (adopting a compressor commonly used in a market refrigerator), the interior of the receiving bin 5 is provided with a bottom bin 21, the bottom surface of the bottom bin 21 is paved with a U-shaped pipe 38, the U-shaped pipe 38 is provided with an evaporator 39, a second circulation pipe 36 is positioned in the preheating cavity 33 and surrounds the outer side wall of the inner hopper 32, one end of the second circulation pipe 36 is communicated with the loop pipe 34, the other end of the second circulation pipe 36 is communicated with the delivery pipe 37, one end of the U-shaped pipe 38 is communicated with the other end of the loop pipe 34 through the compression pump 35, the other end of the U-shaped pipe 38 is communicated with the other end, after the graphene material is expanded and enters the material receiving bin 5 through the discharging pipe 13, the expanded material is in a high-temperature state, so that the material is cooled when entering the material receiving bin 5 and subjected to a temperature difference reaction in the material receiving bin 5, and the low-temperature cooling liquid in the U-shaped pipe 38 can quickly absorb heat of high temperature generated by the material under the action of the evaporator 39 in the bottom bin 21 and the cooling liquid in the U-shaped pipe 38, and the low-temperature cooling liquid is heated and sublimated into high-temperature gas cooling liquid, and then the high-temperature gas cooling liquid is discharged into the second circulating pipe 36 in the preheating cavity 33 through the conveying pipe 37 at one end of the U-shaped pipe 38, a condenser is arranged on the surface of the second circulating pipe 36 in the preheating cavity 33, the high-temperature gas cooling liquid is in the second circulating pipe 36 and subjected to the temperature difference and the condenser in the preheating cavity 33, so that the temperature in the preheating cavity 33 can be quickly sublimated and be raised, and the high-temperature gas coolant liquid is through exothermic desublimation, form low-temperature liquid coolant liquid once more, pass through the return circuit pipe 34 discharge of the second circulating pipe 36 other end again, and through compressor pump 35's effect, make low-temperature liquid coolant liquid in the return circuit pipe 34 compress into low temperature low pressure liquid coolant liquid, thereby flow in the U-shaped pipe 38 once more, absorb once more the heat that 5 inside high-temperature material of butt joint feed bin produced, the circulation effect, on the one hand can carry out rapid cooling to the material after popped fast and handle, on the other hand can preheat the graphite alkene material thing of treating popped in the feeder hopper 3, so that subsequent popped processing, prevent thermal waste promptly, the continuous popped efficiency of graphite alkene material thing has been improved again.

The secondary purification box 7 is divided into an upper layer and a lower layer, a water tank 71 is arranged inside the lower layer of the secondary purification box 7, a connecting pipe 72 is arranged in the middle of the upper surface of the water tank 71, a water receiving tank 73 is arranged inside the upper layer of the secondary purification box 7, a spraying disc 74 is arranged at the top end of the upper layer of the secondary purification box 7 corresponding to the water receiving tank 73, a water inlet 75 is arranged at the top of the secondary purification box 7 corresponding to the middle of the spraying disc 74, an air outlet pipe 76 is arranged on one side surface of the upper end of the secondary purification box 7, an air inlet pipe 77 is arranged at the lower end of the other side surface of the secondary purification box 7, one end of the air inlet pipe 77 is communicated with the upper end of the bag-type dust collector 9, the other end of the air inlet pipe 77 penetrates through the secondary purification box 7 and extends to the inner bottom end of the water tank 71, water is filled inside the water, after the graphene is puffed, high-temperature gas can be generated, the high-temperature gas contains a large amount of harmful substances and graphene dust, the high-temperature gas is discharged into a bag-type dust remover 9 through a communicating pipe 8 for dust treatment, a large amount of graphene dust in the gas can be treated and recovered, then the primarily treated gas is discharged into a water tank 71 in a secondary purification box 7 through an air inlet pipe 77, so that the gas is fully contacted with water in the water tank 71, harmful particles in the gas can be removed, after the gas is fully contacted with the water, the gas can be discharged into a water receiving tank 73 on the upper layer of the secondary purification box 7 through a connecting pipe 72 (the upper layer and the lower layer of the secondary purification box 7 are sealed), the water is injected into a spraying disc 74 through an external water inlet 75 and is sprayed out through spraying holes on the lower surface of the spraying disc, and the treated gas can be fully contacted with the water again, harmful dust and impurities in the gas are further removed, the gas after secondary treatment is discharged through the gas outlet pipe 76, and the problem that the air environment is affected by the harmful dust or impurities in the gas is solved.

The working principle of the invention is as follows: the invention utilizes the high-temperature gas generated in the expansion process of the graphene materials to convey the high-temperature gas in the first circulating pipe 20, the first circulating pipe 20 surrounds the heat preservation cavity 16 in the expansion furnace 1, so that the heat preservation effect can be realized in the expansion furnace 1, simultaneously, the problem that the expansion effect is not ideal enough due to the loss of heat caused by large temperature difference between the inside and the outside of the expansion furnace 1 is avoided, after the expansion of the materials is finished, the high-temperature materials are discharged into the material receiving bin 5 through the discharging pipe 13, after the expanded high-temperature materials enter the material receiving bin 5, the heat generated by the high-temperature materials can be absorbed through the action of the low-temperature cooling liquid in the U-shaped pipe 38 and the evaporator 39, the rapid cooling of the high-temperature materials is realized, and simultaneously, the absorbed heat can be transferred into the preheating cavity 33 through the second circulating pipe 36 to preheat the materials in the feeding hopper 3, thereby can improve the popped effect of graphite alkene material, it is further, have the graphite alkene dust in the popped produced gas of material, consequently, utilize sack cleaner 9 can carry out recycle to the graphite alkene dust in the gas, recycle second grade purifying box 7 carries out secondary purification to gas, so that carry out secondary purification to harmful dust or impurity in the gas, thereby make the combustion gas not contain harmful substance, avoid it to influence air circumstance, the design is not only simple and fast to operate, and carry out recycle to the heat of popped in-process, also can preserve the inside and outside temperature of puffing stove 1 simultaneously, improve popped effect.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims

1. The graphene continuous microwave puffing device comprises a puffing furnace (1) and is characterized in that a material receiving bin (5) is arranged at the lower end of the puffing furnace (1), a furnace cover (10) is arranged at the upper end of the puffing furnace (1), an exhaust pipe (2) is arranged on the upper surface of the furnace cover (10), a feeding hopper (3) is arranged at one end of the puffing furnace (1), a control panel (11) is arranged on one side face of the lower end of the feeding hopper (3), a driving motor (12) is arranged at the bottom end of the feeding hopper (3), a shell (4) is arranged at one end of the driving motor (12), a communicating pipe (8) is connected to the other end of the puffing furnace (1), a bag-type dust collector (9) is connected to the puffing furnace (1) through the communicating pipe (8), a secondary purifying box (7) is arranged on one side of the bag-type dust collector (9), and a spiral, and the inside of expansion furnace (1) is located the one end below of spiral conveying roller (18) and has seted up down silo (17), heat preservation chamber (16) have been seted up to the inside of expansion furnace (1), the inside in heat preservation chamber (16) is provided with heater (19), and the outside that the inside in heat preservation chamber (16) is located heater (19) is provided with first circulating pipe (20), the inside of feeder hopper (3) is provided with interior fill (32), and is provided with between feeder hopper (3) and interior fill (32) and preheats chamber (33), the inside in preheating chamber (33) is provided with second circulating pipe (36).

2. The graphene continuous microwave puffing device according to claim 1, wherein a discharging pipe (13) is arranged between the puffing furnace (1) and the material receiving bin (5), a discharging hole (6) is formed in the lower end of one side face of the material receiving bin (5), one end of the discharging pipe (13) is communicated with a discharging groove (17) in the puffing furnace (1), and the other end of the discharging pipe (13) is communicated with the material receiving bin (5).

3. The graphene continuous microwave puffing device according to claim 1, wherein a belt roller is arranged at one end of the driving motor (12) inside the casing (4), a belt is sleeved on the surface of the belt roller, one end of the spiral conveying roller (18) is rotatably connected with the output end of the driving motor (12) through the belt and the belt roller, and the other end of the spiral conveying roller (18) is rotatably connected with the inner wall of the puffing furnace (1).

4. The graphene continuous microwave puffing device according to claim 1, wherein four exhaust ports (14) are formed in the surface of the furnace cover (10) at equal intervals, an air inlet (15) is formed in one side, close to the exhaust ports (14), of the upper surface of the furnace cover (10) and corresponds to the heat preservation cavity (16), one end of the exhaust pipe (2) is communicated with the inside of the puffing furnace (1) through the exhaust ports (14), the other end of the exhaust pipe (2) is communicated with one end of the first circulating pipe (20) through the air inlet (15), the other end of the first circulating pipe (20) is communicated with the bag-type dust collector (9) through the communicating pipe (8), and the first circulating pipe (20) is arranged inside the heat preservation cavity (16) in a surrounding mode.

5. The graphene continuous microwave puffing device according to claim 1, wherein a stirring roller (31) is arranged at the bottom end of the inner hopper (32), a stirring motor is arranged at one end of the stirring roller (31) inside a shell (4), a loop pipe (34) penetrates through the rear side face of the feeding hopper (3), a conveying pipe (37) penetrates through the front side face of the feeding hopper (3), a compression pump (35) is connected to one end of the loop pipe (34), a bottom bin (21) is arranged inside the material receiving bin (5), a U-shaped pipe (38) is paved on the bottom face of the bottom bin (21), and an evaporator (39) is arranged on the U-shaped pipe (38).

6. The graphene continuous microwave puffing device according to claim 5, wherein the second circulating pipe (36) is located inside the preheating cavity (33) and surrounds the outer side wall of the inner bucket (32), one end of the second circulating pipe (36) is communicated with the loop pipe (34), the other end of the second circulating pipe (36) is communicated with the conveying pipe (37), one end of the U-shaped pipe (38) is communicated with the other end of the loop pipe (34) through the compression pump (35), and the other end of the U-shaped pipe (38) is communicated with the other end of the conveying pipe (37).

7. The graphene continuous microwave puffing device according to claim 1, wherein the secondary purification box (7) is divided into an upper layer and a lower layer, a water tank (71) is arranged inside the lower layer of the secondary purification box (7), a connecting pipe (72) is arranged in the middle of the upper surface of the water tank (71), a water receiving groove (73) is arranged inside the upper layer of the secondary purification box (7), a spraying disc (74) is arranged at the position, corresponding to the water receiving groove (73), of the top inside of the upper layer of the secondary purification box (7), a water inlet (75) is arranged in the middle of the spraying disc (74) corresponding to the top of the secondary purification box (7), an air outlet pipe (76) is arranged on one side surface of the upper end of the secondary purification box (7), and an air inlet pipe (77) is arranged at the lower end of the side surface of the secondary purification.

8. The graphene continuous microwave puffing device according to claim 7, wherein one end of the air inlet pipe (77) is communicated with the upper end of the bag-type dust collector (9), the other end of the air inlet pipe (77) penetrates through the secondary purification box (7) and extends to the bottom end of the interior of the water tank (71), water is injected into the water tank (71), the water tank (71) is communicated with the water receiving tank (73) through a connecting pipe (72), the interior of the spraying disc (74) is of a hollow structure, and a plurality of spraying holes are distributed in the lower surface of the spraying disc (74).