Novel coal mill impeller

Abstract

The utility model discloses a novel coal mill impeller which comprises an inner ring, an outer ring and blades. A fixing part is arranged on the inner ring along the circumference, and a plurality of bolt holes are formed in the fixing part; the cross section of the outer ring is an isosceles trapezoid, and a protruding part is arranged on the outer side of the top of the outer ring. A plurality of blades are fixedly connected between the inner ring and the outer ring and are obliquely arranged. According to the utility model, a metal ceramic casting integrated structure is adopted, so that the impeller has high wear resistance, long service life and repairability, the discharge amount of pebble coal is remarkably reduced, the spontaneous combustion risk is reduced, and the impeller has remarkable economic and environment-friendly benefits.

Description

Technical Field

[0001] This utility model relates to the field of coal mill technology, and more specifically to a novel coal mill impeller. Background Technology

[0002] The existing coal mill impeller assembly has several problems during operation. After approximately 5000 hours of operation, the throttling plate and other impeller parts are prone to detaching into the side body of the coal mill, damaging spare parts such as scrapers, lower skirts, and side body liners, affecting the safe operation of the coal mill. The original impeller has a large discharge of gravel and coal containing a certain amount of raw coal, leading to energy waste and a decline in economic indicators; the impeller has a short lifespan and is prone to damaging the scrapers, affecting the safe operation of the coal mill; and the frequent spontaneous combustion of gravel and coal poses a safety hazard to the normal operation of the equipment.

[0003] Analysis revealed that the main causes of these problems include excessively low throat velocity, which prevents the primary air from effectively separating raw coal from aggregate, and an unreasonable impeller structure design. Low nozzle velocity prevents the aggregate and raw coal ejected from the mill from being quickly blown away, accelerating the wear of the throttling plate and impeller structure. Existing impellers mostly use welded metal components, which have drawbacks such as easy deformation during welding, difficulty in achieving a streamlined shape, high internal stress, significant influence of the welder on weld quality, and poor weld joint toughness, further exacerbating the aforementioned problems. Utility Model Content

[0004] This utility model provides a novel coal mill impeller to solve the problems existing in the prior art.

[0005] To achieve the above objectives, this utility model provides a novel coal mill impeller, comprising: an inner ring, an outer ring, and blades; the inner ring has a fixing part along its circumference, and the fixing part has several bolt holes; the outer ring has an isosceles trapezoidal cross-section, and a protrusion is provided on the outer side of the top of the outer ring; several blades are fixedly connected between the inner ring and the outer ring, and the blades are inclined.

[0006] Preferably, the impeller is made entirely of metal-ceramic material and is formed by one-time casting.

[0007] Preferably, the width of the outer ring air inlet is greater than the width of the air outlet.

[0008] Preferably, the number of bolt holes is 48.

[0009] Preferably, the number of blades is 48.

[0010] Compared with the prior art, the present invention has the following advantages:

[0011] Reduce slag discharge: After optimizing the throat flow velocity, the amount of stone coal discharged is reduced by 30%-40%, and the loss of raw coal is significantly reduced;

[0012] Extended lifespan: The improved wear resistance of the cast structure extends the overall lifespan of the impeller to more than three times that of the original welded parts;

[0013] Safety and environmental protection: Reduce the risk of spontaneous combustion of coal and stone, improve the factory environment, and reduce safety hazards;

[0014] Economic efficiency: Maintenance costs are reduced by 50%, and long-term operating costs are better than those of traditional welded impellers. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0016] Figure 1 The attached figure is a structural schematic diagram of this utility model.

[0017] Figure 2 The attached figure is a cross-sectional view of the present invention.

[0018] Figure 3 The attached figure is an enlarged view of part A of this utility model.

[0019] Reference numerals: 1. Inner ring; 2. Outer ring; 3. Blade; 4. Bolt hole; 5. Protrusion. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this disclosure should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar terms used in the embodiments of this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly. Furthermore, in the description of this application, unless otherwise stated, the term "multiple" refers to two or more. The term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0022] Please see the appendix Figure 1-3 This utility model discloses a novel coal mill impeller, comprising: an inner ring 1, an outer ring 2, and blades 3; the inner ring 1 has a fixing part along its circumference, and the fixing part has several bolt holes 4; the outer ring 2 has an isosceles trapezoidal cross section, and the outer side of the top of the outer ring 2 has a protrusion 5; several blades 3 are fixedly connected between the inner ring 1 and the outer ring 2, and the blades 3 are inclined.

[0023] The streamlined design of the impeller flow section reduces operating resistance, ensures uniform primary airflow distribution, and improves the separation efficiency of gravel and raw coal.

[0024] To further optimize the above technical solution, the impeller is made of metal-ceramic material and is formed by one-time casting.

[0025] The modified impeller is made of metal-ceramic material, which is suitable for large parts subjected to high stress and severe wear.

[0026] Castings offer exceptional design flexibility, allowing for maximum freedom in shape and size selection, and are easily formed and reshaped. The refined design of shape and mass, minimal stress concentration, and superior overall structural integrity all contribute to the flexibility and technological advantages of cast steel design. Castings exhibit the greatest adaptability and variability in metallurgical manufacturing, allowing for the selection of different chemical compositions and microstructures to meet diverse engineering requirements. Mechanical and performance properties can be selected over a wide range through various heat treatment processes, and they possess good weldability and machinability. Compared to structural components, castings can be used under a variety of different operating conditions, and their overall mechanical properties surpass those of any other alloy.

[0027] The impeller, which is cast in one piece, can be directly fixed to the tray, eliminating the need for a connecting ring and reducing the amount of on-site maintenance work.

[0028] The metal-ceramic material comprises a tungsten carbide and cobalt-based alloy with a hardness ≥60HRC. The flow cross-section has a smooth transition, with a throat velocity range of 50-75 m / s. This velocity range effectively reduces slag discharge, decreases the raw coal content in the discharge, reduces energy waste, and improves economic indicators such as unit power supply coal consumption and boiler thermal efficiency. Simultaneously, the smooth flow cross-section effectively reduces equipment wear during operation, extending equipment lifespan.

[0029] To further optimize the above technical solution, the width of the air inlet of the outer ring 2 is greater than the width of the air outlet.

[0030] The narrow-mouth design, which is smaller at the top and larger at the bottom, can effectively increase the wind speed and direction at the throat, which is conducive to the formation of spiral wind, thereby improving the carrying capacity of coal powder. It can blow back the lighter stone coal for further grinding, reducing the amount of stone coal emitted.

[0031] To further optimize the above technical solution, the number of bolt holes 4 is 48.

[0032] The impeller is directly fixed to the tray through bolt hole 4 to ensure the air leakage rate of the circumferential seal at the impeller.

[0033] To further optimize the above technical solution, the number of blades 3 is 48.

[0034] The modified casting blades are thicker than the welded parts and are formed in a single casting process. This design results in lower blade stress, reduced deformation, and superior overall mechanical properties compared to welded components. The high hardness and wear resistance of the blades significantly extend the overall lifespan of the impeller compared to traditional welded components. Specifically, the base material has a lifespan of at least 5 years, and the lifespan of the castings in vulnerable areas is more than three times that of the welded parts, greatly reducing long-term investment costs.

[0035] By optimizing the throat velocity and flow cross-section, the amount of coal slag discharged was effectively reduced, lowering the raw coal content in the discharge, saving energy, and improving the power plant's economic efficiency. The occurrence of spontaneous combustion and flameout of coal slag was reduced, lowering safety hazards and ensuring the normal operation of the equipment and the safety of personnel. Simultaneously, due to the optimized impeller structure, the risk of parts falling off and damaging other equipment was reduced, further improving the safety of the coal mill operation.

[0036] In summary, the novel coal mill impeller of this utility model, through innovative design in terms of materials and structure, effectively solves the problems existing in the current coal mill impeller, and has significant economic and social benefits. It is worthy of widespread promotion and application in the field of coal mill equipment.

[0037] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0038] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A novel coal mill impeller, characterized in that, include: The inner ring (1), outer ring (2), and blades (3) are provided; the inner ring (1) is provided with a fixing part along its circumference, and the fixing part is provided with several bolt holes (4); the outer ring (2) has an isosceles trapezoidal cross section, and the outer side of the top of the outer ring (2) is provided with a protrusion (5); several blades (3) are fixedly connected between the inner ring (1) and the outer ring (2), and the blades (3) are inclined.

2. The novel coal mill impeller according to claim 1, characterized in that, The impeller is made entirely of metal-ceramic material and is formed by one-time casting.

3. The novel coal mill impeller according to claim 1, characterized in that, The width of the air inlet of the outer ring (2) is greater than the width of the air outlet.

4. The novel coal mill impeller according to claim 1, characterized in that, The number of bolt holes (4) is 48.

5. The novel coal mill impeller according to claim 1, characterized in that, The number of blades (3) is 48.

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