CN212409404U

CN212409404U - Power material lifting device for cement kiln and cement kiln adopting power material lifting device

Info

Publication number: CN212409404U
Application number: CN202021158038.9U
Authority: CN
Inventors: 王志宏
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-06-19
Filing date: 2020-06-19
Publication date: 2021-01-26
Anticipated expiration: 2030-06-19

Abstract

The utility model provides a cement kiln is with power lifting device and adopt device's cement kiln relates to cement kiln equipment field, the lower and higher problem of "short circuit" incidence of heat exchange efficiency who has solved prior art existence, power lifting device includes the hole raise the material impeller that drive arrangement was connected to magazine and transmission, the material impeller sets up in raising the material inboard and be located the feed inlet below, accept the platform low reaches, the material impeller is raised the wheel hub that has the pivot and set up in the blade on wheel hub surface, pivot level sets up and movable mounting raises the material in the magazine, drive arrangement is used for driving the rotation of material impeller. The lateral part of the material lifting box of the cement kiln is hermetically connected with the pipe wall of an outlet air pipe of the cyclone barrel, and the feeding pipe is hermetically connected with a feeding hole of the material lifting box. The utility model discloses a lifting device improves the material dispersion and with the gaseous mixed effect of high temperature, improves the heat exchange efficiency of cement kiln system, improves the energy efficiency of cement manufacture process to reduce the emergence of "short circuit".

Description

Power material lifting device for cement kiln and cement kiln adopting power material lifting device

Technical Field

The utility model relates to a cement kiln equipment field, specific theory is a cement kiln is with power lifting devices and adopt device.

Background

In the most common novel dry method kiln outside decomposing cement kiln in the world at present, a material preheating and decomposing system consisting of a multi-stage cyclone and a decomposing furnace is widely used for quickly preheating and decomposing low-temperature materials, wherein the flow direction of the materials is as follows: the method comprises the following steps of feeding a low-temperature material into a primary cyclone, a secondary cyclone, a tertiary cyclone, a four-stage cyclone, a decomposing furnace, a five-stage cyclone and a rotary kiln, wherein the flow direction of high-temperature gas is as follows: the system comprises a rotary kiln, a tertiary air pipe, a decomposing furnace, a five-stage cyclone, a four-stage cyclone, a three-stage cyclone, a two-stage cyclone, a first-stage cyclone and a discharge preheater.

Present novel dry process kiln outer decomposition cement kiln preheater and decomposing furnace used spill material device low temperature material and descend fast downwards along the unloading pipe slant under the effect of gravity, strike the platform department of accepting of spilling material device bottom, receive after the striking to splash towards high temperature tuber pipe direction, fall into in the high temperature tuber pipe after and meet with the interior high temperature gas that rises fast of this tuber pipe, the material is held up and change the direction of motion by the high temperature gas that rises fast, become with the high temperature air current syntropy motion, the material can mix gradually and the mutual contact with high temperature gas at this in-process, the realization is the process of heat transfer for the low temperature material that carries high temperature gas, reach the purpose that preheats the material and reduce gas temperature simultaneously. The materials fall and splash and disperse by virtue of natural flow after impacting the bearing platform, the material flow control capability is poor, the heat exchange efficiency of the system is low, and due to the fact that the downward movement speed of the stranded materials under the action of gravity is high and the downward movement force is large, all the materials are difficult to suspend by high-temperature gas, sometimes even the materials cannot suspend, and the materials can not directly collapse, so-called material short circuit occurs, and the whole cement kiln system can not normally produce.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to design a cement kiln is with power lifting devices and adopt device's cement kiln, improve the material dispersion and with high-temperature gas's mixed effect through the lifting devices that adopts from electrified power to improve the heat exchange efficiency of cement kiln system, improve the energy utilization efficiency of cement manufacture process, realize the purpose of energy saving, and reduce the emergence of "short circuit".

The utility model discloses a following technical scheme realizes:

the utility model provides a power material-lifting device for a cement kiln, which comprises a material-lifting box, a material-lifting impeller and a driving device;

the inner side of the material raising box is provided with a cavity, the upper part of the material raising box is provided with a feeding hole communicated with the cavity, the side part of the material raising box is provided with a discharging hole communicated with the cavity, and the material raising box is provided with a bearing platform;

the material raising impeller is arranged on the inner side of the material raising box, is positioned below the feeding hole and at the downstream of the receiving platform and is used for receiving materials impacted with the receiving platform; the material raising impeller comprises a hub with a rotating shaft and blades arranged on the surface of the hub, and the rotating shaft is horizontally arranged and movably arranged on the material raising box;

the driving device is in transmission connection with the rotating shaft and used for driving the lifting impeller to rotate.

When the structure is arranged, the material spreading box structure is utilized, the material lifting impeller in transmission connection with the driving device is additionally arranged in the material spreading box structure, and the driving device can drive the material lifting impeller to rotate around the rotating shaft horizontally arranged. The material that falls into in the lifting box from the feed inlet is striking the lifting impeller high-speed operation of accepting the platform back to the low reaches department, and violent secondary collision takes place for the material ability and the lifting impeller of gyration afterwards, further breaks up the reunion material, realizes the intensive dispersion to the material, makes material and high temperature hot gas flow more intensive mixing to improve the heat exchange efficiency of cement kiln system, improve the energy utilization efficiency of cement manufacture process. Meanwhile, the material is captured by the blades to move along the rotary direction and then is thrown out along the radial direction of the material lifting impeller to the direction far away from the axis under the action of centrifugal force, so that the material can be lifted into the air pipe at the outlet of the cyclone cylinder along an inclined upward parabolic track to meet with the high-speed upward hot air flow in the air pipe at the outlet of the cyclone cylinder, and finally, the air in the air pipe is fully mixed with the hot air flow and taken away, and the next process is carried out. The motion track of the material flowing into the material lifting impeller is changed for the second time, the material is lifted and scattered into the high-temperature air flow along the upward oblique angle, so that the material has the motion speed in the same direction as the upward air flow, the material is more easily taken away by the high-temperature air, and the short circuit of the material is reduced.

Further for better realization the utility model discloses, adopt the following structure that sets up very much: the material raising impeller is arranged below the bearing platform in an inclined mode.

When the structure is adopted, the material raising impeller is arranged below the bearing platform of the material raising box in an inclined manner, and the blades on the surface of the hub can just bear materials which are rushed down along the material raising impeller at a high speed.

Further for better realization the utility model discloses, adopt the following structure that sets up very much: the hub is sequentially provided with a plurality of blades which are arranged at equal angles along the circumferential direction of the hub.

Further for better realization the utility model discloses, adopt the following structure that sets up very much: the blades extend linearly in the height direction along the radial direction of the winnowing impeller, or the blades extend in a bending manner in the height direction towards the rear of the rotation direction of the winnowing impeller.

Further for better realization the utility model discloses, adopt the following structure that sets up very much: the blades are involute blades.

Further for better realization the utility model discloses, adopt the following structure that sets up very much: the receiving platform is a bevel board with a downstream end lower than an upstream end.

When the structure is adopted, the bearing platform is obliquely arranged, so that materials can more smoothly and violently impact the material raising impeller positioned at the downstream under the action of gravity and inertia after impacting the bearing platform, and a better impact dispersion effect is obtained.

Further for better realization the utility model discloses, adopt the following structure that sets up very much: the inclination angle between the bearing platform and the horizontal plane is 10-15 degrees.

Further for better realization the utility model discloses, adopt the following structure that sets up very much: the height of the blades is gradually reduced from the middle of the material lifting impeller towards two ends along the axial direction of the material lifting impeller.

When the structure is adopted, the lifting impeller is integrally of a drum-shaped structure with two thin ends and a thick middle part, so that the distribution range of the materials after being lifted and scattered is larger, the circular cross section of the lifting hot air flow can be better covered, the materials and the hot air flow are fully contacted and mixed, the heat exchange between the materials and the air flow is improved, and the heat exchange efficiency of the cement kiln preheater and the decomposing furnace system is improved.

The utility model also provides a cement kiln, including inlet pipe, whirlwind section of thick bamboo export tuber pipe and foretell power material lifting device, raise the lateral part sealing connection of magazine the pipe wall of whirlwind section of thick bamboo export tuber pipe, the discharge gate with the inside intercommunication of whirlwind section of thick bamboo export tuber pipe, the inlet pipe with raise the magazine feed inlet sealing connection.

Further for better realization the utility model discloses, adopt the following structure that sets up very much: the rotation direction of the lifting impeller is from bottom to top at one side close to the bearing platform, and from top to bottom at one side far away from the bearing platform.

Further for better realization the utility model discloses, adopt the following structure that sets up very much: the central line of the rotating shaft is tangent to the section circle of the outlet air pipe of the cyclone cylinder.

When the structure is adopted, the material lifting impeller is half-inserted into the outlet air pipe of the cyclone cylinder, so that the ventilation area of the outlet air pipe of the original cyclone cylinder is reduced to some extent, the air speed of the outlet air pipe of the original cyclone cylinder is improved, and the material carrying capacity of the ascending hot air flow is improved. Meanwhile, when the material lifting impeller is half-inserted into the outlet air pipe of the cyclone cylinder, the whole volume of the power material lifting device can be reduced, and the power material lifting device is convenient to be connected with a discharging pipe of an established cement kiln system.

The utility model has the advantages of it is following and beneficial effect:

the utility model discloses in, utilize current material box structure that spills, increase the material impeller that raises that sets up and be connected with the drive arrangement transmission in its inside, drive arrangement can drive the pivot gyration that the material impeller set up around the level. The material that falls into in the lifting box from the feed inlet is striking the lifting impeller high-speed operation of accepting the platform back to the low reaches department, and violent secondary collision takes place for the material ability and the lifting impeller of gyration afterwards, further breaks up the reunion material, realizes the intensive dispersion to the material, makes material and high temperature hot gas flow more intensive mixing to improve the heat exchange efficiency of cement kiln system, improve the energy utilization efficiency of cement manufacture process. Meanwhile, the material is captured by the blades to move along the rotary direction and then is thrown out along the radial direction of the material lifting impeller to the direction far away from the axis under the action of centrifugal force, so that the material can be lifted into the air pipe at the outlet of the cyclone cylinder along an inclined upward parabolic track to meet with the high-speed upward hot air flow in the air pipe at the outlet of the cyclone cylinder, and finally, the air in the air pipe is fully mixed with the hot air flow and taken away, and the next process is carried out. The motion track of the material flowing into the material lifting impeller is changed for the second time, the material is lifted and scattered into the high-temperature air flow along the upward oblique angle, so that the material has the motion speed in the same direction as the upward air flow, the material is more easily taken away by the high-temperature air, and the short circuit of the material is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic half-section view of a power lifting device;

FIG. 2 is a schematic structural view of a winnowing impeller;

FIG. 3 is a schematic structural diagram of a part of a cement kiln using a dynamic lifting device;

FIG. 4 is a schematic process flow diagram of the material lifting device part;

labeled as:

1. a material raising box; 11. a feed inlet; 12. a discharge port; 13. a receiving platform;

2. a material raising impeller; 21. a hub; 22. a blade; 23. a rotating shaft;

3. a drive device; 31. a motor; 32. a drive train support; 33. a coupling;

4. a bearing seat;

5. a feed pipe;

6. an outlet air pipe of the cyclone.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. It is to be understood that the embodiments described are only some embodiments of the invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

Example 1:

the utility model provides a cement kiln is with power lifting devices, improves the material dispersion and with the gaseous mixed effect of high temperature through the lifting devices who adopts from taking power to improve the heat exchange efficiency of cement kiln system, improve the energy utilization efficiency of cement manufacture process, realize the purpose of energy saving, and reduce the emergence of "short circuit", as shown in figure 1, figure 2, figure 3, figure 4, set up to following structure especially:

comprises a material raising box 1, a material raising impeller 2 and a driving device 3.

Basically, the shell of the lifting box 1 is a hollow polyhedron with a cavity at the inner side. The inclined plane part of the upper part of the material lifting box 1 is separately provided with a round feed inlet 11, and the feed inlet 11 is communicated with the cavity inside the material lifting box 1 and is used for being connected with the feed pipe 5 to receive materials. The side part of the material raising box 1 is not sealed by a plate to form a discharge port 12 communicated with the cavity, the profile of the discharge port 12 is matched with the cyclone outlet air pipe 6 to be connected, a bearing platform 13 is arranged in the material raising box 1, and the bearing platform 13 is positioned below the discharge port 12.

The material raising impeller 2 is used for receiving materials which are impacted with the receiving platform 13. The material raising impeller 2 is arranged in the inner cavity of the material raising box 1 and is integrally positioned below the feeding hole 11 and at the downstream position of the bearing platform 13. The material raising impeller 2 comprises a hub 21, blades 22 and a rotating shaft 23, the rotating shaft 23 is coaxial with the hub 21, the hub 21 is sleeved on the rotating shaft 23, and the blades 22 are fixedly arranged on the surface of the hub 21. The rotating shaft 23 is horizontally arranged, two ends of the rotating shaft 23 penetrate through steel plates on two sides of the material raising box 1 to the outside of the material raising box 1, and a labyrinth sealing device is arranged at a position where the rotating shaft 23 penetrates through the shell of the material raising box 1 so as to prevent air leakage and material leakage from the position. Two extending ends of the rotating shaft 23 are sleeved with a bearing respectively, a bearing seat 4 is fixed on the transmission system bracket 32 of the driving device 3 and the outer wall of the shell of the material raising box 1 through bolts, and the bearings at two ends of the rotating shaft 23 are arranged in the corresponding bearing seats 4. The shaft 23 is rotatable with the hub 21 and the blades 22 about the axis of the shaft 23.

The driving device 3 comprises a transmission system bracket 32 fixedly arranged on the outer wall of the material throwing box 1 in a welding mode, a motor 31 arranged on the transmission system bracket 32 and a pair of couplers 33, and the motor 31 is a variable-frequency high-speed motor. The shaft 23 is single-side driven, and its length ends at the bearing at the end of the shaft 23 without the drive 3. An end cover is arranged on one side of the bearing seat 4 far away from the material pumping box 1 to ensure the sealing of the bearing seat 4. At one end of the rotating shaft 23 with the driving device 3, the rotating shaft 23 penetrates through the bearing and then is provided with a half of the coupling 33, and the half of the coupling 33 is arranged at the main shaft of the motor 31, so that the motor 31 and the lifting impeller 2 are in transmission connection to drive the lifting impeller 2 to rotate.

Specifically, the blades 22 have a plurality of blades, such as twelve blades, and the twelve blades are sequentially arranged at equal angles around the circumference of the hub 21 and are radially distributed. The blades 22 may be linear blades extending straight in the height direction along the radial direction of the impeller 2, or curved blades extending curved in the height direction toward the rear of the rotation direction of the impeller 2, and the curved blades are preferably involute blades. The specific blade form is specifically determined as needed in the actual application.

As a preferable arrangement of the receiving platform 13 in this embodiment, the receiving platform 13 is a slope plate with a downstream end lower than an upstream end, and the angle of inclination between the receiving platform 13 and the horizontal plane is 10 to 15 °. The receiving platform 13 is obliquely arranged, so that the material from the cyclone outlet air pipe 6 can more smoothly and violently impact the material lifting impeller 2 positioned at the lower downstream from the higher upstream under the action of gravity and inertia after impacting the receiving platform 13, and a better impact dispersion effect is obtained.

Above structural scheme utilizes current material scattering box structure, increases the material impeller 2 that raises that sets up and be connected with drive arrangement 3 transmission in its inside, and drive arrangement 3 can drive material impeller 2 and revolve around the pivot 23 of level setting. The material that falls into in the material raising box 1 from feed inlet 11 is hitting the material raising impeller 2 high-speed operation of accepting platform 13 back to the low reaches department, and the violent secondary collision takes place for the material ability with the material raising impeller 2 of gyration afterwards, further breaks up the reunion material, realizes the intensive dispersion to the material, makes material and high temperature hot gas flow more intensive mixing to improve the heat exchange efficiency of cement kiln system, improve the energy utilization efficiency of cement manufacture process. Meanwhile, the material is captured by the blades 22 and moves along the rotary direction, and then is thrown out along the radial direction of the material lifting impeller 2 to the direction far away from the axis under the action of centrifugal force, so that the material can be lifted into the cyclone outlet air pipe 6 along the inclined upward parabolic track to meet with the high-speed upward hot air in the cyclone outlet air pipe 6, and finally, the air pipe air and the hot air are fully mixed and taken away to enter the next working procedure. The motion track of the material flowing into the material lifting impeller 2 is changed for the second time, the material is lifted along the upward oblique angle and is scattered into the high-temperature air flow, so that the material has the motion speed in the same direction as the upward air flow, the material is easier to be taken away by the high-temperature air, and the short circuit of the material is reduced.

Example 2:

this embodiment is further optimized on the basis of above-mentioned embodiment, and further for better realization the utility model discloses, adopt the following structure that sets up very much:

the material raising impeller 2 is integrally arranged at the oblique lower part of the bearing platform 13, specifically, the axis of the rotating shaft 23 is positioned at the oblique lower part of the bearing platform 13, and the cross-section circle of the material raising impeller 2 can be tangent to or intersected with the extension line of the bearing platform 13. When the material raising impeller 2 is arranged obliquely below the bearing platform 13 of the material raising box 1, the material raising impeller 2 is arranged at a position which can enable the blades 22 on the surface of the hub 21 to just bear the materials which are undershot at a high speed along the material raising impeller 2.

Example 3:

the hub 21 in the material raising impeller 2 is an equal-diameter hub, and the height of the blades 22 is gradually reduced from the middle of the material raising impeller 2 towards two ends along the axial direction of the material raising impeller 2, so that the whole material raising impeller 2 is in a drum-shaped structure with two thin ends and a thick middle part, the purpose of doing so is to enable the distribution shape of the material after being raised and scattered to be better matched with the circular cross section of the outlet air pipe 6 of the cyclone cylinder, the distribution range of the material is larger, the circular cross section of the rising hot air flow can be better covered, the full contact and mixing of the material and the hot air flow are realized, the heat exchange of the material and the air flow is improved, and the heat exchange efficiency of a cement preheater and a decomposing furnace.

Example 4:

the present embodiment further provides a cement kiln based on the above embodiments, and particularly adopts the following arrangement structure:

the cement kiln adopts the power material-lifting device in the embodiment 3, and the power material-lifting device is arranged at a required position for use. The structure provided with the power material raising device comprises a feeding pipe 5, a cyclone outlet air pipe 6 and a power material raising device. An opening is formed in the pipe wall of the cyclone outlet air pipe 6, a lateral part discharge port 12 of the material raising box 1 is aligned to the opening and is in sealing connection with the periphery of the opening, the discharge port 12 is communicated with the inside of the cyclone outlet air pipe 6, the feeding pipe 5 is obliquely arranged, and the bottom end of the feeding pipe 5 is aligned to a feeding port 11 in the upper part of the material raising box 1 and is in sealing connection with the feeding port.

As a preferred arrangement scheme of the material lifting impeller 2 in this embodiment, a center line of a rotating shaft 23 of the material lifting impeller 2 is tangent to a cross-sectional circle of the cyclone outlet air duct 6, so that the material lifting impeller 2 is half-inserted into the cyclone outlet air duct 6, which can reduce the ventilation area of the original cyclone outlet air duct at this location, thereby increasing the wind speed at this location and increasing the material carrying capacity of the ascending hot air flow. Meanwhile, when the material lifting impeller 2 is half-inserted into the cyclone cylinder outlet air pipe 6, the whole volume of the power material lifting device can be reduced, and the power material lifting device is convenient to be connected with a discharging pipe of an established cement kiln system.

The rotation direction of the material raising impeller 2 is from bottom to top at the side close to the bearing platform 13, and from top to bottom at the side far away from the bearing platform 13.

Above structural scheme improves the material dispersion and with high-temperature gas's mixed effect through the lifting devices who adopts from taking power to improve cement kiln system's heat exchange efficiency, improve the energy utilization efficiency of cement manufacture process, realize energy saving's purpose. The dynamic material lifting device replaces the traditional static material spreading on the cement kiln cyclone, so the installation position of the dynamic material lifting device is the position of the original static material spreading box of each cyclone of the cement kiln. During production, as shown in fig. 4, the hollow arrow represents ascending hot air flow, the black dots represent materials, the materials in the cement kiln system flow into the lifting box 1 of the power lifting device along the feeding pipe 5 of the cyclone cylinder, the materials fall to the higher end of the inclined bearing platform 13 under the action of gravity and inertia, flow to the lifting impeller 2 along the lower downstream direction of the bearing platform 13 after being collided, are collided and dispersed by the blades 22 rotating at high speed and are thrown upwards into the outlet air pipe 6 of the cyclone cylinder in an inclined mode to meet the high-speed ascending hot air flow in the air pipe, and finally are fully mixed and taken away by the air pipe and the hot air flow to enter the next process.

This power lifting device has the lifting impeller 2 that can turn round at a high speed, and the blade 22 that the lifting impeller 2 was taken can break the material of reunion when contacting with the material, makes the dispersion effect of material better than the material dispersion effect of traditional material scattering device. The rotary motion of the material raising impeller 2 can change the motion track of the material flowing into the blades 22, and the material is raised and scattered into the high-temperature airflow along an upward oblique angle, so that the material has a motion speed in the same direction as the ascending airflow, and in the traditional material scattering device, the material is downwards rushed into the ascending airflow under the action of gravity, so that compared with the prior art, the power material raising device in the embodiment can make the material more easily taken away by the high-temperature gas, and the problem of material short circuit existing in the traditional material scattering device is reduced. The axial outer edge of the blades 22 of the power material lifting device is drum-shaped, so that the distribution range of the material after being lifted and scattered can better cover the circular section of the ascending hot air flow, the full contact and mixed contact of the material and the air flow are realized, the heat exchange of the material and the air flow is improved, and the heat exchange efficiency of the cement kiln preheater and the decomposing furnace system is improved.

The above description is only for the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present invention, and all should be covered within the protection scope of the present invention.

Claims

1. The utility model provides a cement kiln is with power lifting devices which characterized in that: comprises a material raising box (1), a material raising impeller (2) and a driving device (3);

the inner side of the material raising box (1) is provided with a cavity, the upper part of the material raising box (1) is provided with a feeding hole (11) communicated with the cavity, the side part of the material raising box (1) is provided with a discharging hole (12) communicated with the cavity, and the material raising box (1) is provided with a bearing platform (13);

the material raising impeller (2) is arranged on the inner side of the material raising box (1), is positioned below the feeding hole (11) and at the downstream of the receiving platform (13), and is used for receiving materials impacted with the receiving platform (13); the material raising impeller (2) comprises a hub (21) with a rotating shaft (23) and blades (22) arranged on the surface of the hub (21), wherein the rotating shaft (23) is horizontally arranged and movably arranged on the material raising box (1);

the driving device (3) is in transmission connection with the rotating shaft (23) and is used for driving the material raising impeller (2) to rotate.

2. The power material-raising device for the cement kiln as claimed in claim 1, characterized in that: the material raising impeller (2) is arranged obliquely below the bearing platform (13).

3. The power material-raising device for the cement kiln as claimed in claim 1, characterized in that: the hub (21) is sequentially provided with a plurality of blades (22) which are arranged at equal angles along the circumferential direction.

4. The power material-raising device for the cement kiln as claimed in claim 1, characterized in that: the blades (22) extend linearly in the height direction along the radial direction of the lifting impeller (2), or the blades (22) extend in a bent manner in the height direction towards the rear of the rotation direction of the lifting impeller (2).

5. The power material-raising device for the cement kiln as claimed in claim 4, characterized in that: the blades (22) are involute blades.

6. The power material-raising device for the cement kiln as claimed in claim 2, characterized in that: the receiving platform (13) is a bevel plate with the downstream end lower than the upstream end.

7. The power material-raising device for the cement kiln as claimed in claim 6, characterized in that: the inclination angle between the bearing platform (13) and the horizontal plane is 10-15 degrees.

8. The power material-lifting device for the cement kiln according to any one of claims 1 to 7, characterized in that: the height of the blades (22) is gradually reduced from the middle of the material lifting impeller (2) towards two ends along the axial direction of the material lifting impeller (2).

9. A cement kiln is characterized in that: the power winnowing device comprises a feeding pipe (5), a cyclone outlet air pipe (6) and the power winnowing device according to any one of claims 1 to 8, wherein the side part of the winnowing box (1) is hermetically connected with the pipe wall of the cyclone outlet air pipe (6), the discharging port (12) is communicated with the interior of the cyclone outlet air pipe (6), and the feeding pipe (5) is hermetically connected with the feeding port (11) of the winnowing box (1).

10. A cement kiln according to claim 9, characterized in that: the central line of the rotating shaft (23) is tangent to the section circle of the cyclone outlet air pipe (6).