Environment-friendly three-cylinder dryer

Abstract

The invention relates to the technical field of three-cylinder dryers, and discloses an environment-friendly three-cylinder dryer which comprises a base plate and a composite cylinder, the composite cylinder is arranged above the base plate, a driving rotating assembly is arranged between the base plate and the composite cylinder, an end cover is arranged at the front end of the composite cylinder, and a feeding pipe opening is formed in the center of the end cover; the end cover is provided with an air inlet feeding mechanism through a feeding pipe opening, and an air guide discharging mechanism is arranged at the end, away from the air inlet feeding mechanism, of the composite barrel. According to the environment-friendly three-cylinder drying machine, the air guiding and discharging mechanism is arranged, a material can be effectively limited and blocked through a material baffle with holes, it is guaranteed that airflow can pass through the air guiding and discharging mechanism, air can be further effectively filtered through a filter screen plate, it is guaranteed that the air exhausted to the outside reaches the emission standard, and after long-time use, the environment-friendly three-cylinder drying machine is not prone to falling off. The perforated striker plate and the filter screen plate can be effectively taken out by rotating the opening knob and pulling the handle, cleaning and maintenance are convenient, and time and labor are saved.

Description

Technical Field

[0001] The invention relates to the technical field of three-drum drying machines, in particular to an environmentally friendly three-drum drying machine. Background Art

[0002] The three-drum dryer is an improved product based on the single-drum rotary dryer. The dryer cylinder is composed of three coaxial horizontally placed inner, middle and outer cylinders stacked together. The material and hot air flow enter the inner to outer cylinder in turn. After the Z-shaped reciprocating flow of the machine body, the heat energy is fully utilized to dry the material before it is discharged.

[0003] Since the existing three-drum dryer generally uses multiple motors to drive the composite cylinder to rotate, the structure is easily damaged and cannot ensure the smooth rotation of the composite cylinder; the material blocks to be dried cannot be effectively crushed during the feeding process, and the material blocks are easy to block the feed port; in order to ensure the cleanliness of the airflow discharged at the end of the three-drum dryer, a filtering device needs to be installed. However, the filter element of the filtering device is generally installed inside the device, which is not convenient to disassemble for cleaning or replacement. The filtered hot air flow is directly discharged to the outside, resulting in energy waste. Therefore, it is necessary to provide an environmentally friendly three-drum dryer to solve the above problems. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides an environmentally friendly three-drum drying machine, which solves the problems mentioned in the above background.

[0005] The present invention provides the following technical solution: an environmentally friendly three-drum drying machine, comprising a base plate and a composite drum, wherein the composite drum is arranged above the base plate, a driving rotating assembly is arranged between the base plate and the composite drum, an end cover is arranged at the front end of the composite drum, a feed pipe opening is arranged at the center of the end cover, an air intake and feeding mechanism is arranged at the end cover through the feed pipe opening, and an air guide and unloading mechanism is arranged at one end of the composite drum away from the air intake and feeding mechanism;

[0006] The air intake and feeding mechanism comprises a first sleeve and a main pipeline, wherein the first sleeve is arranged at the end of the main pipeline, and the main pipeline is rotatably connected to the feed pipe opening of the end cover through the first sleeve;

[0007] The air-guiding material-feeding mechanism comprises a shell and a second sleeve, wherein the second sleeve is arranged at the front opening of the shell, and the shell is rotatably connected to the outlet pipe at the end of the composite cylinder through the second sleeve.

[0008] Preferably, the composite cylinder includes an outer cylinder, a middle cylinder and an inner cylinder, the middle cylinder is arranged inside the outer cylinder, the inner cylinder is arranged inside the middle cylinder, the inner cylinder feed port is connected with the outer cylinder feed port, the outer cylinder and the middle cylinder as well as the middle cylinder and the inner cylinder are connected by supporting connecting rods, and spiral lifting plates are arranged on the inner walls of the outer cylinder, the middle cylinder and the inner cylinder.

[0009] Preferably, the driving rotation assembly includes a mounting frame, a driving gear, a synchronous wheel and a synchronous belt. Two mounting frames are provided, and the two mounting frames are respectively arranged at the two ends of the upper surface of the base plate. End shafts are arranged at the centers of both sides of the driving gear. The driving gear is rotatably arranged at the two ends inside the mounting frame through the end shafts. The end shaft inside the driving gear passes through the side wall of the mounting frame and is connected to the synchronous wheel. The two synchronous wheels on one side of the mounting frame are connected through a synchronous belt transmission.

[0010] Preferably, the driving rotation assembly also includes a bidirectional motor, a driving shaft and a reducer. The bidirectional motor is arranged on the upper surface of the base plate, and the reducer is arranged at both ends of the bidirectional motor. The output ends of the bidirectional motor are respectively connected to the two reducers, one end of the driving shaft is connected to the reducer, and the end of the driving shaft away from the reducer is connected to the synchronous wheel. Gear rings are provided at both ends of the outer surface of the composite cylinder, and the gear rings are meshed with the driving gears.

[0011] Preferably, the air intake and feeding mechanism also includes a feed pipe, a feed hopper and a crushing roller. The lower end of the feed pipe is connected to the main pipeline, and the upper end of the feed pipe is connected to the feed hopper. A hot air inlet is arranged at the front end of the main pipeline. Two crushing rollers are arranged, and both crushing rollers are rotatably arranged inside the feed hopper.

[0012] Preferably, the front end cam shafts of the two crushing rollers pass through the side wall of the lower hopper and are provided with gear plates, the two gear plates are meshed with each other, a motor seat is provided at the lower end of the side wall of the lower hopper, a crushing motor is provided on the upper end surface of the motor seat, and the output end of the crushing motor is connected to a gear plate.

[0013] Preferably, the air guiding and discharging mechanism also includes a side bracket, a filter box and an exhaust pipe, the side bracket is arranged on both sides of the shell, the lower end of the side bracket is connected to the base plate, the lower end of the shell is provided with a discharge port, the filter box is arranged on the upper end surface of the shell, and the exhaust pipe is arranged on the upper end surface of the filter box.

[0014] Preferably, two card slots are provided on the front side of the filter box, and sockets are provided in the card slots. A filter screen plate is inserted in the upper socket of the filter box, and a perforated material baffle plate is inserted in the lower socket of the filter box. Card plates are provided at the front end of the perforated material baffle plate and the filter screen plate.

[0015] Preferably, a knob is provided on the front of the filter box and located between the two slots, a handle is provided at the center of the front of the card plate, and an arc-shaped notch that cooperates with the knob is opened on the card plate.

[0016] Preferably, an air guide pipe is provided on one side of the exhaust pipe, and one end of the air guide pipe away from the exhaust pipe is connected to the feed pipe, and valves are provided on both the exhaust pipe and the air guide pipe.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The environmentally friendly three-drum dryer is provided with a driving rotation component and works through a bidirectional motor. The two driving shafts can be driven to rotate synchronously through a reducer, and then the driving shaft can drive the driving gears inside the two mounting frames to rotate synchronously, and then the driving gear can drive the composite drum to rotate through the gear ring to dry the material. There is no need for multiple motors to drive the composite drum, so as to ensure the stability of the composite drum; by providing an air intake and feeding mechanism, when the material enters the lower hopper through the conveyor belt, the crushing motor works and under the transmission action of the gear plate, it can drive the two crushing rollers to rotate synchronously, and then the crushing rollers can effectively crush the block material to avoid blockage.

[0019] 2. The environment-friendly three-drum dryer is equipped with an air-guiding and unloading mechanism. The perforated baffle plate can effectively limit and block the material and ensure that the airflow can pass through. The filter screen can further filter the gas to ensure that the gas discharged to the outside meets the emission standards. After long-term use, the perforated baffle plate and the filter screen can be effectively removed by turning the knob and pulling the handle, which is convenient for cleaning and maintenance, saving time and effort. By opening the valve on the air guide pipe, the filtered hot air flow can be effectively guided into the inside of the unloading pipe, which can preheat the material inside the unloading pipe. At the same time, the blowing of the air flow can accelerate the passage of the material through the unloading pipe, further avoiding material blockage and energy waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is one of the overall structural schematic diagrams of the environmentally friendly three-drum drying machine of the present invention;

[0021] Figure 2 This is the second schematic diagram of the overall structure of the environmentally friendly three-drum drying machine of the present invention;

[0022] Figure 3 It is a structural schematic diagram of the base plate and the driving rotating assembly of the present invention;

[0023] Figure 4 It is a schematic diagram of the structure of the composite tube of the present invention;

[0024] Figure 5 It is a structural schematic diagram of the air intake and feeding mechanism of the present invention;

[0025] Figure 6 It is a structural schematic diagram of the air-guiding material feeding mechanism of the present invention;

[0026] Figure 7 It is a structural schematic diagram of the filter box of the present invention;

[0027] Figure 8 For the present invention Figure 3 A magnified schematic diagram of the structure in the middle.

[0028] In the figure: 1, base plate; 2, driving rotating assembly; 201, mounting frame; 202, driving gear; 203, synchronous wheel; 204, synchronous belt; 205, bidirectional motor; 206, driving shaft; 207, reducer; 3, composite cylinder; 301, outer cylinder; 302, middle cylinder; 303, inner cylinder; 304, end cover; 4, gear ring; 5, air intake and feeding mechanism; 501, first sleeve; 502, main pipeline; 503, discharge pipe; 504, discharge hopper; 5 05. Crushing roller; 506. Gear plate; 507. Crushing motor; 508. Motor seat; 6. Air guide and unloading mechanism; 601. Side bracket; 602. Shell; 603. Second bushing; 604. Discharge port; 605. Filter box; 606. Exhaust pipe; 607. Air guide pipe; 608. Valve; 609. Slot; 610. Socket; 611. Perforated baffle plate; 612. Filter screen plate; 613. Card plate; 614. Knob; 615. Handle. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] See also Figure 1-8 An environmentally friendly three-drum drying machine includes a base plate 1 and a composite drum 3, the composite drum 3 is arranged above the base plate 1, a driving rotating assembly 2 is arranged between the base plate 1 and the composite drum 3, an end cover 304 is arranged at the front end of the composite drum 3, a feed pipe opening is arranged at the center of the end cover 304, an air intake and feeding mechanism 5 is arranged at the end of the composite drum 3 away from the air intake and feeding mechanism 5, and an air guide and unloading mechanism 6 is arranged;

[0031] The air intake and feeding mechanism 5 includes a first sleeve 501 and a main pipe 502. The first sleeve 501 is arranged at the end of the main pipe 502. The main pipe 502 is rotatably connected to the feed pipe opening of the end cover 304 through the first sleeve 501.

[0032] The air-guiding unloading mechanism 6 comprises a shell 602 and a second sleeve 603 . The second sleeve 603 is arranged at the front opening of the shell 602 . The shell 602 is rotatably connected to the outlet pipe at the end of the composite cylinder 3 through the second sleeve 603 .

[0033] Among them; the composite cylinder 3 includes an outer cylinder 301, a middle cylinder 302 and an inner cylinder 303, the middle cylinder 302 is arranged inside the outer cylinder 301, the inner cylinder 303 is arranged inside the middle cylinder 302, the feed port of the inner cylinder 303 is connected with the feed port of the outer cylinder 301, the outer cylinder 301 and the middle cylinder 302 as well as the middle cylinder 302 and the inner cylinder 303 are connected by supporting connecting rods, and spiral lifting plates are arranged on the inner walls of the outer cylinder 301, the middle cylinder 302 and the inner cylinder 303. By setting the supporting connecting rod, the stability between the outer cylinder 301, the middle cylinder 302 and the inner cylinder 303 is guaranteed, the material and the hot air flow enter the inner to outer cylinder body in turn, and after the Z-shaped reciprocating flow of the body, the heat energy is fully utilized to dry the material before being discharged to ensure the drying effect.

[0034] Among them; the driving rotation component 2 includes a mounting frame 201, a driving gear 202, a synchronous wheel 203 and a synchronous belt 204. Two mounting frames 201 are provided. The two mounting frames 201 are respectively arranged at the two ends of the upper surface of the base plate 1. End shafts are arranged at the centers of both sides of the driving gear 202. The driving gear 202 is rotatably arranged at the two ends inside the mounting frame 201 through the end shafts. The end shaft inside the driving gear 202 passes through the side wall of the mounting frame 201 and is connected to the synchronous wheel 203. The two synchronous wheels 203 on one side of the mounting frame 201 are connected through the synchronous belt 204. The mounting frame 201 is provided to facilitate the installation of the driving gear 202. The synchronous wheel 203 and the synchronous belt 204 can realize the synchronous rotation of the two driving gears 202 at both ends of the mounting frame 201.

[0035] Among them; the driving rotation component 2 also includes a bidirectional motor 205, a driving shaft 206 and a reducer 207. The bidirectional motor 205 is arranged on the upper end surface of the base plate 1, and the reducer 207 is arranged at both ends of the bidirectional motor 205. The output ends of the bidirectional motor 205 are respectively connected to the two reducers 207, one end of the driving shaft 206 is connected to the reducer 207, and the end of the driving shaft 206 away from the reducer 207 is connected to the synchronous wheel 203. Both ends of the outer surface of the composite cylinder 3 are sleeved with a gear ring 4, and the gear ring 4 is meshed with the driving gear 202. Through the operation of the bidirectional motor 205, the two driving shafts 206 can be driven to rotate synchronously through the reducer 207, and then the driving shaft 206 can drive the driving gears 202 inside the two mounting frames 201 to rotate synchronously, and then the driving gear 202 can drive the composite cylinder 3 to rotate through the gear ring 4 to dry the material. There is no need for multiple motors to drive the composite cylinder 3, thereby ensuring the stability of the composite cylinder 3.

[0036] Among them; the air intake feeding mechanism 5 also includes a feeding pipe 503, a feeding hopper 504 and a crushing roller 505, the lower end of the feeding pipe 503 is connected to the main pipeline 502, the upper end of the feeding pipe 503 is connected to the feeding hopper 504, the front end of the main pipeline 502 is provided with a hot air inlet, and two crushing rollers 505 are provided, and the two crushing rollers 505 are rotatably arranged inside the feeding hopper 504, and the front end convex shafts of the two crushing rollers 505 pass through the side wall of the feeding hopper 504 and are provided with a gear plate 506, and the two gear plates 5 06 are meshed with each other, a motor seat 508 is provided at the lower end of the side wall of the lower hopper 504, a crushing motor 507 is provided on the upper end surface of the motor seat 508, and the output end of the crushing motor 507 is connected to a gear plate 506. When the material enters the lower hopper 504 through the conveyor belt, the crushing motor 507 works, and under the transmission action of the gear plate 506, the two crushing rollers 505 can be driven to rotate synchronously, and then the crushing rollers 505 can effectively crush the block materials to avoid blockage.

[0037] Among them, the air guide and discharge mechanism 6 also includes a side bracket 601, a filter box 605 and an exhaust pipe 606. The side bracket 601 is arranged on both sides of the shell 602, and the lower end of the side bracket 601 is connected to the base plate 1. The lower end of the shell 602 is provided with a discharge port 604, the filter box 605 is arranged on the upper end surface of the shell 602, and the exhaust pipe 606 is arranged on the upper end surface of the filter box 605. Two card slots 609 are provided on the front of the filter box 605, and a socket 610 is provided in the card slot 609. A filter screen plate 612 is inserted in the upper socket 610 of the filter box 605, and a perforated material baffle plate 611 is inserted in the lower socket 610 of the filter box 605. The perforated material baffle plate 611 and the front end of the filter screen plate 612 are provided with a card plate 613. The front of the filter box 605 is located between the two card slots 609 A knob 614 is provided, and a handle 615 is provided at the center of the front of the card plate 613. The card plate 613 is provided with an arc-shaped notch that cooperates with the knob 614. Initially, the knob 614 is turned in a vertical state, and the upper and lower ends of the knob 614 are both stuck in the arc-shaped notch on the card plate 613 to ensure the stability of the perforated material baffle plate 611 and the filter screen plate 612. The perforated material baffle plate 611 can effectively limit and block the material and ensure that the airflow can pass through. The filter screen plate 612 can further effectively filter the gas to ensure that the gas discharged to the outside meets the emission standards. After long-term use, the knob 614 is turned to open and the handle 615 is pulled to effectively take out the perforated material baffle plate 611 and the filter screen plate 612, which is convenient for cleaning and maintenance, saving time and effort.

[0038] Among them; an air guide pipe 607 is arranged on one side of the exhaust pipe 606, and the air guide pipe 607 is connected to the discharge pipe 503 at one end away from the exhaust pipe 606, and valves 608 are arranged on the exhaust pipe 606 and the air guide pipe 607. By opening the valve 608 on the air guide pipe 607, the filtered hot air flow can be effectively guided into the inside of the discharge pipe 503, which can play a role in preliminary preheating of the material inside the discharge pipe 503. At the same time, the blowing of the air flow can accelerate the passage of the material through the discharge pipe 503, further avoiding the blockage of the material.

[0039] Working principle: when the material enters the lower hopper 504 through the conveyor belt, the crushing motor 507 works, and under the transmission action of the gear plate 506, the two crushing rollers 505 can be driven to rotate synchronously, and then the crushing rollers 505 can effectively crush the block materials to avoid blockage. The bidirectional motor 205 works, and the two drive shafts 206 can be driven to rotate synchronously through the reducer 207, and then the drive shaft 206 can drive the drive gears 202 inside the two installation frames 201 to rotate synchronously, and then the drive gear 202 can drive the composite cylinder 3 to rotate through the gear ring 4, and the material and hot air flow enter the inner to outer cylinder in turn. After the Z-shaped reciprocating flow of the machine body, the heat energy is fully utilized to dry the material before it is unloaded to ensure the drying effect.

[0040] Furthermore, initially, the knob 614 is turned in a vertical state, and the upper and lower ends of the knob 614 are both stuck in the arc-shaped notches on the clamping plate 613, ensuring the stability of the perforated material baffle plate 611 and the filter screen plate 612. The perforated material baffle plate 611 can effectively limit the material and ensure that the airflow can pass through. The filter screen plate 612 can further effectively filter the gas to ensure that the gas discharged to the outside meets the emission standards. By opening the valve 608 on the air guide pipe 607, the filtered hot air flow can be effectively guided into the interior of the discharge pipe 503, which can preheat the material inside the discharge pipe 503. At the same time, the blowing of the air flow can accelerate the material to pass through the discharge pipe 503, further avoiding the blockage of the material. After long-term use, the knob 614 can be turned to open and the handle 615 can be pulled to effectively remove the perforated material baffle plate 611 and the filter screen plate 612, which is convenient for cleaning and maintenance, saving time and effort.

[0041] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An environmentally friendly three-drum drying machine, comprising a base plate (1) and a composite drum (3), wherein the composite drum (3) is arranged above the base plate (1), characterized in that: A driving rotating assembly (2) is arranged between the base plate (1) and the composite cylinder (3); an end cover (304) is arranged at the front end of the composite cylinder (3); a feed pipe opening is arranged at the center of the end cover (304); an air intake and feeding mechanism (5) is arranged on the end cover (304) through the feed pipe opening; and an air guide and unloading mechanism (6) is arranged at one end of the composite cylinder (3) away from the air intake and feeding mechanism (5); The air intake and feeding mechanism (5) comprises a first sleeve (501) and a main pipe (502), wherein the first sleeve (501) is arranged at the end of the main pipe (502), and the main pipe (502) is rotatably connected to the feeding pipe opening of the end cover (304) through the first sleeve (501); The air-guiding material-feeding mechanism (6) comprises a shell (602) and a second shaft sleeve (603), wherein the second shaft sleeve (603) is arranged at the front opening of the shell (602), and the shell (602) is rotatably connected to the outlet pipe at the end of the composite cylinder (3) via the second shaft sleeve (603).

2. The environmentally friendly three-drum dryer according to claim 1, characterized in that: The composite cylinder (3) comprises an outer cylinder (301), a middle cylinder (302) and an inner cylinder (303); the middle cylinder (302) is arranged inside the outer cylinder (301); the inner cylinder (303) is arranged inside the middle cylinder (302); a feed port of the inner cylinder (303) is connected to a feed port of the outer cylinder (301); the outer cylinder (301) and the middle cylinder (302) as well as the middle cylinder (302) and the inner cylinder (303) are connected via supporting connecting rods; and spiral lifting plates are arranged on the inner walls of the outer cylinder (301), the middle cylinder (302) and the inner cylinder (303).

3. The environmentally friendly three-drum dryer according to claim 1, characterized in that: The driving rotation assembly (2) comprises a mounting frame (201), a driving gear (202), a synchronous wheel (203) and a synchronous belt (204). Two mounting frames (201) are provided, and the two mounting frames (201) are respectively provided at two ends of the upper surface of the base plate (1). End shafts are provided at the centers of both sides of the driving gear (202). The driving gear (202) is rotatably provided at two ends inside the mounting frame (201) via the end shafts. The end shaft inside the driving gear (202) passes through the side wall of the mounting frame (201) and is connected to the synchronous wheel (203). The two synchronous wheels (203) on one side of the mounting frame (201) are connected by a synchronous belt (204).

4. The environmentally friendly three-drum dryer according to claim 3, characterized in that: The driving rotating assembly (2) also includes a bidirectional motor (205), a driving shaft (206) and a reducer (207); the bidirectional motor (205) is arranged on the upper end surface of the base plate (1); the reducer (207) is arranged at both ends of the bidirectional motor (205); the output ends of the bidirectional motor (205) are respectively connected to the two reducers (207); one end of the driving shaft (206) is connected to the reducer (207); the end of the driving shaft (206) away from the reducer (207) is connected to the synchronous wheel (203); and both ends of the outer surface of the composite cylinder (3) are sleeved with gear rings (4); the gear rings (4) and the driving gear (202) are meshed with each other.

5. The environmentally friendly three-drum dryer according to claim 1, characterized in that: The air intake and feeding mechanism (5) also includes a feeding pipe (503), a feeding hopper (504) and a crushing roller (505); the lower end of the feeding pipe (503) is connected to the main pipeline (502); the upper end of the feeding pipe (503) is connected to the feeding hopper (504); a hot air inlet is arranged at the front end of the main pipeline (502); two crushing rollers (505) are arranged, and both crushing rollers (505) are rotatably arranged inside the feeding hopper (504).

6. The environmentally friendly three-drum dryer according to claim 5, characterized in that: The front end convex shafts of the two crushing rollers (505) both pass through the side wall of the lower hopper (504) and are provided with a gear plate (506), the two gear plates (506) are meshed with each other, a motor seat (508) is provided at the lower end of the side wall of the lower hopper (504), a crushing motor (507) is provided on the upper end surface of the motor seat (508), and the output end of the crushing motor (507) is connected to a gear plate (506).

7. The environmentally friendly three-drum dryer according to claim 5, characterized in that: The air guide and discharge mechanism (6) further comprises a side bracket (601), a filter box (605) and an exhaust pipe (606); the side bracket (601) is arranged on both sides of the shell (602); the lower end of the side bracket (601) is connected to the base plate (1); the lower end of the shell (602) is provided with a discharge port (604); the filter box (605) is arranged on the upper end surface of the shell (602); and the exhaust pipe (606) is arranged on the upper end surface of the filter box (605).

8. The environmentally friendly three-drum dryer according to claim 7, characterized in that: The filter box (605) has two slots (609) on the front side, and a socket (610) is provided in the slot (609). A filter screen plate (612) is inserted into the upper socket (610) of the filter box (605), and a perforated material blocking plate (611) is inserted into the lower socket (610) of the filter box (605). A slot (613) is provided at the front end of the perforated material blocking plate (611) and the filter screen plate (612).

9. The environmentally friendly three-drum dryer according to claim 8, characterized in that: A knob (614) is provided on the front of the filter box (605) and between the two slots (609); a handle (615) is provided at the center of the front of the card plate (613); and an arc-shaped notch that cooperates with the knob (614) is provided on the card plate (613).

10. The environmentally friendly three-drum dryer according to claim 9, characterized in that: An air guide pipe (607) is provided on one side of the exhaust pipe (606), and one end of the air guide pipe (607) away from the exhaust pipe (606) is connected to the feed pipe (503), and valves (608) are provided on both the exhaust pipe (606) and the air guide pipe (607).

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