阅读说明：本技术 一种聚丙烯酰胺干燥用分段加热热烘炉 (Polyacrylamide is dry with segmentation heating heat baker ) 是由 李金江 钟华东 荣洪杰 于 2021-08-25 设计创作，主要内容包括：本发明涉及一种聚丙烯酰胺干燥用分段加热热烘炉,涉及化工设备技术领域,包括炉座、炉体、继热筒、输送机、气筒、锥筒和加热管,炉体固连在炉座顶部,继热筒固连在炉体顶部,输送机固连在炉体一侧,气筒固连在炉座内,气筒顶部伸入炉体内且位于输送机输出端正下方,锥筒滑动连接在气筒上端,气筒内通入加压空气以将锥筒吹起,若干根加热管间隔分布在气筒四周的炉体内以对炉体内腔加热,本发明具有可使聚丙烯酰胺粉料快速干燥的优点。(The invention relates to a sectional heating heat drying furnace for drying polyacrylamide, which relates to the technical field of chemical equipment and comprises a furnace base, a furnace body, a heat relay cylinder, a conveyor, an air cylinder, a conical cylinder and heating pipes, wherein the furnace body is fixedly connected to the top of the furnace base, the heat relay cylinder is fixedly connected to the top of the furnace body, the conveyor is fixedly connected to one side of the furnace body, the air cylinder is fixedly connected into the furnace base, the top of the air cylinder extends into the furnace body and is positioned right below the output end of the conveyor, the conical cylinder is slidably connected to the upper end of the air cylinder, pressurized air is introduced into the air cylinder to blow up the conical cylinder, and the plurality of heating pipes are distributed in the furnace body around the air cylinder at intervals to heat the inner cavity of the furnace body.)

1. A section heating hot oven for drying polyacrylamide is characterized in that: the continuous heating furnace comprises a furnace base (1), a furnace body (2), a continuous heating cylinder (3), a conveyor (4), an air cylinder (5), a conical cylinder (6) and heating pipes (7), wherein the furnace body (2) is fixedly connected to the top of the furnace base (1), the continuous heating cylinder (3) is fixedly connected to the top of the furnace body (2), the conveyor (4) is fixedly connected to one side of the furnace body (2), the air cylinder (5) is fixedly connected to the inside of the furnace base (1), the top of the air cylinder (5) extends into the inside of the furnace body (2) and is positioned under the output end of the conveyor (4), the conical cylinder (6) is slidably connected to the upper end of the air cylinder (5), pressurized air is introduced into the air cylinder (5) to blow up the conical cylinder (6), and the plurality of heating pipes (7) are distributed in the furnace body (2) around the air cylinder (5) at intervals to heat the inner cavity of the furnace body (2).

2. The sectional heating and heating oven for drying polyacrylamide as claimed in claim 1, wherein: the bottom of the inner cavity of the stove base (1) is fixedly connected with a base (11), a heating coil (12) is fixedly connected on the base (11), and the heating coil (12) is embedded into the air cylinder (5).

3. The sectional heating and heating oven for drying polyacrylamide as claimed in claim 2, wherein: an air inlet pipe (51) is fixedly connected to one side of the air cylinder (5), the air inlet pipe (51) is communicated with the air cylinder (5), ash cleaning manholes (13) are erected on two sides of the bottom of the furnace base (1), the ash cleaning manholes (13) are communicated with the inner cavity of the furnace base (1), and the air inlet pipe (51) extends out of the furnace base (1) through the ash cleaning manholes (13) and is connected with an air pump.

4. The sectional heating and heating oven for drying polyacrylamide as claimed in claim 3, wherein: the top of the air cylinder (5) is provided with a nozzle (52), the caliber of the nozzle (52) is smaller than that of the air cylinder (5), and the outer diameter of the conical cylinder (6) is equal to that of the nozzle (51).

5. The sectional heating and heating oven for drying polyacrylamide as claimed in claim 4, wherein: the bottom of the conical cylinder (6) is fixedly connected with a cylindrical sliding column (65), the inner wall of the nozzle (52) is fixedly connected with a support (53), the sliding column (65) is connected in the support (53) in a sliding mode, the bottom of the sliding column (65) is fixedly connected with an annular limiting disc (66), and the outer diameter of the limiting disc (66) is larger than the aperture of a pore channel of the support (53) in contact with the sliding column (65).

6. The sectional heating and heating oven for drying polyacrylamide as claimed in claim 5, wherein: the cone cylinder (6) comprises an air cone surface (61), a sealing surface (62) and a material cone surface (63), the air cone surface (61) is in a shape of an inverted frustum, and the air cone surface (61) is fixedly connected with the sliding column (65); the sealing surface (62) is annular, the sealing surface (62) is fixedly connected to the top of the air cone surface (61), and the outer diameter of the sealing surface (62) is equal to the caliber of the nozzle (52); the material conical surface (63) is conical, the material conical surface (63) is fixedly connected to the top of the sealing surface (62), and the air conical surface (61) and the material conical surface (63) are hollow.

7. The sectional heating and heating oven for drying polyacrylamide as claimed in claim 6, wherein: the included angle between the generatrix of the air conical surface (61) and the axial line of the conical cylinder (6) is smaller than the included angle between the generatrix of the material conical surface (63) and the axial line of the conical cylinder (6).

8. The sectional heating and heating oven for drying polyacrylamide as claimed in claim 7, wherein: the inner cavity of the cone (6) is filled with gas or sandy soil.

9. The sectional heating and heating oven for drying polyacrylamide as claimed in claim 1, wherein: the spiral rod (43) is connected to the rotation of conveyer (4), and helical blade on spiral rod (43) butts on conveyer (4) internal face, and conveyer (4) one end has linked firmly motor (42), and motor (42) rotate with spiral rod (43) to be connected, and conveyer (4) are located spiral rod (43) top and have linked firmly feed cylinder (41), are equipped with polyacrylamide powder in feed cylinder (41).

10. The sectional heating and heating oven for drying polyacrylamide as claimed in claim 1, wherein: a heat-supply area (21) is arranged at the top of the furnace body (2), a plurality of heat-supply pipes (22) are fixedly connected in the heat-supply area (21), and the power of the heat-supply pipes (22) is lower than that of the heating pipes (7); the top of the furnace body (1) is fixed with a secondary heating cylinder (3) through a flange plate and bolts, a plurality of secondary heating pipes (31) are fixedly connected in the secondary heating cylinder (3) at intervals, and the power of the secondary heating pipes (31) is lower than that of the secondary heating pipes (22); the top of the heat relay cylinder (3) is fixedly connected with an air outlet pipe (32), and the air outlet pipe (32) is communicated with the storage tank.

Technical Field

The invention relates to the technical field of chemical equipment, in particular to a sectional heating and heating oven for drying polyacrylamide.

Background

At present, the polyacrylamide drying mode is usually carried out by adopting a natural gas hot oven, and the drying mode is well received by manufacturers when the hot oven is pushed out, but the following problems are prominent along with the application time: the drying heat is mainly the radiant heat of a burner, the temperature graduation of the radiant heat is unbalanced, the improvement is realized by the driving of a fan, but the waste heat radiation is basically relied on in the middle of a drying furnace, the temperature of the materials in the tempering stage before discharging is not controlled, and the overall heat efficiency is difficult to improve compared with the heat value of fuel; the air inlet of the oven is mainly a fan, particularly for a horizontal oven, the air inlet is low, the ground dust is more, the air inlet quality of the oven is poor, and the product purity and the product chromaticity are influenced; when powder materials are treated by a heat oven taking combustion as a heating mode, a horizontal oven is generally adopted, and one important disadvantage of the horizontal oven is large floor space, larger equipment investment and unsuitability for the trend of high intensive development of the land of the factory; the drying of powder materials has higher requirement on the dispersion degree of the materials, the materials are generally dispersed by a cyclone separator, the cyclone separator is generally driven by a motor, the application of the motor in a high-temperature environment is limited, the materials are particularly easy to burn out, the material dispersion effect is influenced, and the operation stability of equipment faces a larger challenge; the traditional electric heating oven has the problems that the heating pipe is easy to age and the heat efficiency is low; the drying of powder product materials also has the problem to be solved urgently that the powder is easy to be hung on the wall; meanwhile, the automation degree of the equipment is low, the operation is unstable, and the product quality is influenced.

Therefore, in view of the above disadvantages, it is desirable to provide a sectional heating oven for drying polyacrylamide.

Disclosure of Invention

Technical problem to be solved

The invention aims to solve the technical problem of low heat efficiency of the existing hot oven.

(II) technical scheme

In order to solve the technical problem, the invention provides a sectional heating heat drying furnace for drying polyacrylamide, which comprises a furnace base, a furnace body, a heat relay cylinder, a conveyor, an air cylinder, a conical cylinder and heating pipes, wherein the furnace body is fixedly connected to the top of the furnace base, the heat relay cylinder is fixedly connected to the top of the furnace body, the conveyor is fixedly connected to one side of the furnace body, the air cylinder is fixedly connected into the furnace base, the top of the air cylinder extends into the furnace body and is positioned right below the output end of the conveyor, the conical cylinder is slidably connected to the upper end of the air cylinder, pressurized air is introduced into the air cylinder to blow up the conical cylinder, and the plurality of heating pipes are distributed in the furnace body around the air cylinder at intervals to heat the inner cavity of the furnace body.

As a further explanation of the present invention, preferably, the bottom of the inner cavity of the stove base is fixedly connected with a base, the base is fixedly connected with a heating coil, and the heating coil is embedded into the air cylinder.

As a further explanation of the invention, preferably, one side of the air cylinder is fixedly connected with an air inlet pipe, the air inlet pipe is communicated with the air cylinder, two sides of the bottom of the furnace base are provided with ash removal manholes, the ash removal manholes are communicated with the inner cavity of the furnace base, and the air inlet pipe extends out of the furnace base through the ash removal manholes and is connected with an air pump.

As a further explanation of the present invention, it is preferable that the top of the gas cylinder is provided with a spout, the caliber of the spout is smaller than the caliber of the gas cylinder, and the outer diameter of the cone is equal to the caliber of the spout.

As a further explanation of the present invention, preferably, the bottom of the conical cylinder is fixedly connected with a cylindrical sliding column, the inner wall of the nozzle is fixedly connected with a support, the sliding column is slidably connected in the support, the bottom of the sliding column is fixedly connected with an annular limiting disc, and the outer diameter of the limiting disc is larger than the aperture of the pore canal of the support contacting with the sliding column.

As a further explanation of the present invention, preferably, the cone comprises an air cone surface, a sealing surface and a material cone surface, the air cone surface is in an inverted frustum shape, and the air cone surface is fixedly connected with the sliding column; the sealing surface is annular and fixedly connected to the top of the gas cone surface, and the outer diameter of the sealing surface is equal to the caliber of the nozzle; the material conical surface is conical, the material conical surface is fixedly connected to the top of the sealing surface, and the air conical surface and the material conical surface are both hollow.

As a further description of the present invention, preferably, an included angle between the generatrix of the gas cone surface and the axis of the cone cylinder is smaller than an included angle between the generatrix of the material cone surface and the axis of the cone cylinder.

As a further illustration of the present invention, it is preferred that the cone inner cavity is filled with gas or sand.

As a further explanation of the present invention, it is preferable that a screw rod is rotatably connected in the conveyor, a helical blade on the screw rod abuts against an inner wall surface of the conveyor, one end of the conveyor is fixedly connected with a motor, the motor is rotatably connected with the screw rod, the conveyor is fixedly connected above the screw rod with a charging barrel, and polyacrylamide powder is filled in the charging barrel.

As a further explanation of the invention, preferably, a heat-sustaining region is arranged at the top of the furnace body, a plurality of heat-sustaining pipes are fixedly connected in the heat-sustaining region, and the power of the heat-sustaining pipes is lower than that of the heating pipes; the top of the furnace body is fixed with a heat relay cylinder through a flange plate and bolts, a plurality of heat relay pipes are fixedly connected in the heat relay cylinder at intervals, and the power of the heat relay pipes is lower than that of the heat relay pipes; the top of the heat relay cylinder is fixedly connected with an air outlet pipe which is communicated with the storage tank.

(III) advantageous effects

The technical scheme of the invention has the following advantages:

according to the invention, through designing the air cylinder with the conical cylinder, pressurized air is blown into the air cylinder, and the air outlet pipe is matched for pumping, so that powder can smoothly flow out of the charging cylinder, and the powder can be blown to the air outlet pipe, and the drying of the powder is realized by utilizing the enhanced air flow and the high-temperature baking in the furnace body. And when the wind power is weakened, the cone cylinder can naturally droop to seal the air cylinder, so that powder is prevented from entering the air cylinder, and multiple purposes are achieved.

Drawings

FIG. 1 is a sectional view of a furnace body of the present invention;

FIG. 2 is a view showing the installation position of an intake pipe of the present invention;

FIG. 3 is a view showing the internal structure of the hearth according to the present invention;

FIG. 4 is a top view of the present invention;

FIG. 5 is an enlarged view of A in FIG. 4;

FIG. 6 is a full sectional view of the present invention;

fig. 7 is an enlarged view of B in fig. 6.

In the figure: 1. a furnace base; 11. a base; 12. a heating coil; 13. a manhole for ash removal; 14. a blanking port; 2. a furnace body; 21. a heat-sustaining zone; 22. a heat-sustaining pipe; 3. a heat relay cylinder; 31. a relay pipe; 32. an air outlet pipe; 4. a conveyor; 41. a charging barrel; 42. a motor; 43. a screw rod; 5. an air cylinder; 51. an air inlet pipe; 52. a spout; 53. a support; 6. a conical cylinder; 61. a gas cone surface; 62. a sealing surface; 63. a material conical surface; 64. a cavity; 65. a traveler; 66. a limiting disc; 7. heating a tube; 71. a limiting sleeve.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, 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 some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

The utility model provides a polyacrylamide is dry with segmentation heating heat baker, combine figure 1, figure 2, including furnace base 1, furnace body 2, a heat transfer section of thick bamboo 3, conveyer 4, inflator 5, awl section of thick bamboo 6 and heating pipe 7, furnace body 2 links firmly at furnace base 1 top, a heat transfer section of thick bamboo 3 links firmly at furnace body 2 top, conveyer 4 links firmly in furnace body 2 one side, inflator 5 links firmly in furnace base 1, 5 tops of inflator stretch into in furnace body 2 and be located under the 4 output of conveyer, 6 sliding connection of awl section of thick bamboo 6 are in 5 upper ends of inflator, let in pressurized air in inflator 5 and can blow up awl section of thick bamboo 6, a plurality of heating pipe 7 interval distribution are in 5 furnace body 2 all around of inflator in order to 2 inner chambers of furnace body heating.

Combine fig. 1, fig. 3, stove seat 1 is square metal casing, and 1 inner chamber bottom of stove seat has linked firmly base 11, is equipped with the circuit board in the base 11, has linked firmly heating coil 12 on the base 11, and heating coil 12 adopts resistance-type heating tube, and heating coil 12 is snakelike distribution, and 12 both ends of heating coil imbed in the base 11 with circuit board electric connection, the circuit board is heating coil 12 power supplies so that heating coil 12 generates heat, and heating coil 12 imbeds to the inflator 5 in. The two sides of the bottom of the furnace base 1 are provided with ash cleaning manholes 13, and the ash cleaning manholes 13 are communicated with the inner cavity of the furnace base 1. The top of the furnace base 1 is provided with a blanking port 14 so as to communicate the inner cavity of the furnace base 1 with the inner cavity of the furnace body 2, the air cylinder 5 extends into the furnace body 2 through the blanking port 14, and the caliber of the blanking port 14 is larger than the outer diameter of the air cylinder 5 so as to enable impurities with large particle diameter to fall into the furnace base 1.

Referring to fig. 1 and 2, the furnace body 2 is a cylindrical barrel, and the heating pipes 7 are annularly distributed on the inner wall of the furnace body 2. The top of the furnace body 2 is provided with a truncated cone-shaped heat-continuing area 21, a plurality of heat-continuing pipes 22 are distributed in the heat-continuing area 21 at intervals in an annular shape, the material and the structure of the heat-continuing pipes 22 are the same as those of the heating pipes 7, and the power of the heat-continuing pipes 22 is lower than that of the heating pipes 7. The secondary heating cylinder 3 is also a cylindrical cylinder, the secondary heating cylinder 3 is fixedly connected to the top of the heat-sustaining region 21 through a flange plate and bolts, a plurality of secondary heating pipes 31 are annularly distributed in the secondary heating cylinder 3 at intervals, the materials and the structures of the secondary heating pipes 31 and the heating pipes 7 are the same, and the power of the secondary heating pipes 31 is lower than that of the heat-sustaining pipes 22. Wherein the heating pipe 7 is set to be between 95 and 115 ℃; the setting temperature of the heat-continuing pipe 22 is between 75 ℃ and 100 ℃; the temperature of the heat relay pipe 31 is set to be 55-80 ℃. Setting temperature rise and temperature fall gradient signals according to the heating temperature rise delay allowance of each section of heating pipe, and realizing rapid temperature rise and heat preservation operation according to the number of the heating pipes corresponding to the signal start and stop, wherein the temperature regulation gradient is preferably between 3 ℃ and 6 ℃, and is preferably 5 ℃. The top of the heat relay cylinder 3 is fixedly connected with an air outlet pipe 32, and the output end of the air outlet pipe 32 is connected with a storage tank for storing the dried materials.

Referring to fig. 4 and 6, the conveyor 4 is a cylindrical straight cylinder, the conveyor 4 is obliquely and fixedly connected to one side of the furnace body 2, one end of the conveyor 4 with low height extends into the furnace body 2, and the other end of the conveyor 4 extends out of the furnace body 2. The screw rod 43 is rotationally connected in the conveyor 4, the helical blade on the screw rod 43 is abutted on the inner wall surface of the conveyor 4, one end of the conveyor 4 is fixedly connected with the motor 42, the motor 42 is rotationally connected with the screw rod 43, the conveyor 4 is positioned above the screw rod 43 and is fixedly connected with the charging barrel 41, and powdery materials such as polyacrylamide are filled in the charging barrel 41.

Referring to fig. 3 and 6, the air cylinder 5 is a cylindrical pipeline, one side of the air cylinder 5 is fixedly connected with an air inlet pipe 51, the air inlet pipe 51 is communicated with the air cylinder 5, and the air inlet pipe 51 extends out of the furnace base 1 through the ash removal manhole 13 and is connected with an air pump. The top of the air cylinder 5 is provided with a nozzle 52, the caliber of the nozzle 52 is smaller than that of the air cylinder 5, and the outer diameter of the conical cylinder 6 is equal to the caliber of the nozzle 52. An air cylinder 5 is provided for introducing pressurized air into the furnace body 2, and a nozzle 52 is provided to increase the flow rate of the air, making it easier for the air to blow up the powder. Referring to fig. 5, the bottom of the conical cylinder 6 is fixedly connected with a cylindrical sliding column 65, the inner wall of the nozzle 52 is fixedly connected with a support 53, the sliding column 65 is slidably connected in the support 53, the bottom of the sliding column 65 is fixedly connected with an annular limiting disc 66, and the outer diameter of the limiting disc 66 is larger than the aperture diameter of a pore channel of the support 53 in contact with the sliding column 65. The bracket 53 and the sliding column 65 are used for connecting the air cylinder 5 to the conical cylinder 6, and can limit the conical cylinder 6 to move up and down only along the axial direction of the furnace body 2, and the limiting disc 66 is arranged to prevent the conical cylinder 6 from slipping off the nozzle 52.

With reference to fig. 6 and 7, the cone 6 includes an air cone surface 61, a sealing surface 62 and a material cone surface 63, the air cone surface 61 is in an inverted frustum shape, and the air cone surface 61 is fixedly connected with a sliding column 65; the sealing surface 62 is annular, the sealing surface 62 is fixedly connected to the top of the gas cone surface 61, and the outer diameter of the sealing surface 62 is equal to the caliber of the nozzle 52; the material conical surface 63 is conical, the material conical surface 63 is fixedly connected to the top of the sealing surface 62, and the included angle between the generatrix of the gas conical surface 61 and the axis of the conical cylinder 6 is smaller than the included angle between the generatrix of the material conical surface 63 and the axis of the conical cylinder 6. The gas cone surface 61 and the material cone surface 63 are hollow, so that the gas cone surface 61, the sealing surface 62 and the material cone surface 63 enclose a cavity 64, and the cavity 64 can be filled with gas or sand, wherein the gas density is lower than that of air. Can make under the same atmospheric pressure, make the air change or more difficult flow into in furnace body 2, make pressurized air to the buoyancy effect of powder changeable, can separate the impurity of different particle size and weight in the powder, when buoyancy is less, then required powder that weight is lighter can get into in the outlet duct 32, impurity granule that weight is heavier then drops to the furnace base 1 in through blanking mouth 14, clear away through asking ash man's hole 13 after drying work accomplishes, save the screening of screen cloth, save man-hour.

With reference to fig. 1 and 2, the heating pipe 7 mainly includes an alloy heating pipe, a tungsten wire heating pipe and an infrared heating pipe, the alloy heating pipe is preferred, each heating pipe 7, the heat continuing pipe 22 and the heat continuing pipe 31 are independently and automatically controlled through a circuit and are not affected by each other, and the heating pipe 7, the heat continuing pipe 22 and the heat continuing pipe 31 are sleeved with steel pipes, so that the heating pipe 7, the heat continuing pipe 22 and the heat continuing pipe 31 are prevented from being scratched by powder in the movement process. Wherein the end height of the heating pipe 7 is slightly higher than the output port height of the conveyor 4, the heating pipe 7 is sleeved with a limit sleeve 71 in a sliding manner, and the limit sleeve 71 is fixedly connected to the inner wall of the furnace body 2 and used for fixing the heating pipe 7.

When the powder drying is performed, pressurized air is injected into the air inlet pipe 51, and the heating coil 12 and the heating pipe 7, the heat continuing pipe 22 and the heat continuing pipe 31 are started to perform preheating. At the moment, the pressurized air flows through the heating coil 12 to heat the pressurized air, then the conical cylinder 6 is blown up from the nozzle 52, a gap is formed between the conical cylinder 6 and the nozzle 52 to enable the pressurized air to flow into the furnace body 2, then the powder is injected into the conveyor 4 through the material cylinder 41, the screw rod 43 conveys the powder into the furnace body 2 under the driving of the motor 42, the powder falls on the material conical surface 63 of the conical cylinder 6 and flows around the conical cylinder 6 under the action of gravity until the powder is contacted with the pressurized air, the powder is blown to the inner wall of the furnace body 2 by the pressurized air, at the moment, the air pump on the air outlet pipe 32 is started to pump the air in the furnace body 2, the powder flows to the continuous heating area 21 and the continuous heating cylinder 3 under the action of the air pump of the pressurized air and the air outlet pipe 32, the dispersed heating of the pressurized air and the sectional heating of the heating pipe 7, the continuous heating pipe 22 and the continuous heating pipe 31 can enable the powder to be sufficiently heated and dried, and the material that flows through the continuous heating cylinder 3 is heated the temperature and is close to normal temperature, can avoid the high and difficult problem that scatters and disappears and lead to the powder rotten of powder middle part temperature of the powder of piling after getting into the storage tank.

In summary, the air cylinder 5 with the cone cylinder 6 is arranged, so that the problem that powder cannot fall smoothly due to the fact that the powder is directly blown to the discharge hole of the conveyor 4 can be solved, air can be dispersed by the aid of the air cone surface 61, the powder can be primarily dispersed by the aid of the material cone surface 63, and the dispersed air can be further blown to disperse the powder, so that the heating area of the powder is increased, the heat exchange efficiency is higher, and the drying efficiency is higher. And combines the multistage heating of furnace body 2 to maintain gentle temperature gradient, improve drying efficiency. And the automatic temperature control device controls the start and stop of each heating component and the air pump and the power adjustment, so that the drying precision is improved. Compared with the existing general fuel hot oven, the heat utilization rate can be improved by 32 percent, the electric energy consumption is reduced by about 15 percent, and the drying rate accuracy can be controlled within 1 percent. In addition, the heating pipe 7 is reasonable in height design, so that powder can be heated, impact of the powder on the heating pipe 7 can be reduced to the maximum degree, and the service life of the heating pipe 7 is prolonged.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.