A loading device for a medium-speed coal mill

Abstract

This utility model discloses a loading device for a medium-speed coal mill, relating to the technical field of medium-speed coal mills. It includes a base, guide rods, an upper guide block, and springs. The bottom of the base has a hemispherical base positioning hole for engaging with a hemispherical pressure ring positioning head of the pressure ring. Two guide rods are fixedly mounted on the top of the base, each with a spring sleeved on it. The upper guide block has two sleeve holes, and its top has a hemispherical guide block positioning hole for engaging with a hemispherical set screw positioning head of the set screw. A base positioning sleeve is coaxially fixed to the base positioning hole. A base support tube is mounted on one end of the base along its length. The bottom end face of the base support tube is flush with the bottom end face of the base positioning sleeve, so that both end faces are on the same plane. This ensures that the base and pressure ring remain horizontal, guaranteeing that the sleeve holes of the guide rods and upper guide blocks remain concentric, and preventing accelerated wear of the guide rods and upper guide blocks due to skewness of the loading device, or causing the coal mill to jam and stop operating.

Description

Technical Field

[0001] This utility model relates to the field of medium-speed coal mill technology, and in particular to a loading device for a medium-speed coal mill. Background Technology

[0002] A coal mill is a machine used in thermal power plants to crush coal into pulverized coal. It is an important auxiliary equipment for pulverized coal boilers. The main working principle of a coal mill is to feed raw coal into the mill and grind it into pulverized coal. Then, the pulverized coal is blown into the boiler furnace by hot air through exhaust fans and pulverized coal pipelines for combustion.

[0003] Medium-speed coal mills are commonly used, with the ZQM158 or ZQM178 models having a more complex structure. During operation, they require six sets of loading devices inside the mill chamber. Each loading device consists of a base, guide rod, upper guide block, and two sets of springs. These six loading devices are evenly distributed circumferentially on the top surface of the mill chamber's pressure ring. Each loading device has a corresponding set screw (typically DN80mm in diameter) above it. The upper guide block has a hemispherical positioning hole at its top center. The top of the set screw is threaded onto the mill chamber, and the bottom of the set screw has a hemispherical positioning head that abuts against the positioning hole. When the set screw is turned clockwise, the upper guide block presses down on the two sets of springs, which in turn applies pressure to the pressure ring, allowing the pressure ring to exert pressure on the upper grinding ring's steel balls to grind the coal powder. However, existing coal mill loading devices have defects due to insufficient production design: the base of the loading device is usually equipped with a hemispherical positioning hole and a hemispherical positioning head on the pressure ring for positioning. However, if the contact is unstable, the loading device is prone to tilting during the operation of the coal mill, which will accelerate the wear of the upper guide block and guide shaft, increase the frequency of replacing the loading device and increase the labor intensity of maintenance personnel. Utility Model Content

[0004] The purpose of this utility model is to solve the above-mentioned technical problems and provide a loading device for a medium-speed coal mill. This device addresses the issue that existing medium-speed coal mills, especially the ZQM158 or ZQM178 models, have a skewed loading device during operation, which leads to accelerated wear of the loading device or the entire loading device tipping over, causing the coal mill to jam and stop operating, or even resulting in the grinding ring breaking. This invention aims to avoid potential hazards to the safe and stable operation of the entire boiler.

[0005] To achieve the above objectives, this utility model provides the following solution: a loading device for a medium-speed coal mill, comprising a base, guide rods, an upper guide block, and springs. The bottom of the base is provided with a hemispherical base positioning hole, which is used to cooperate with the hemispherical pressure ring positioning head of the pressure ring. Two vertically arranged guide rods are fixedly provided on the top of the base, and each guide rod is fitted with a spring. The upper guide block is provided with two fitting holes for fitting onto the guide rods. The top of the upper guide block is provided with a hemispherical guide block positioning hole, which is used to cooperate with the hemispherical set screw positioning head of the set screw. A base positioning sleeve is coaxially fixed to the base positioning hole, and the base positioning sleeve is used to fit onto the pressure ring positioning head. A base support tube is provided at one end of the base in the length direction. The base support tubes are symmetrically arranged along the midpoint of the width direction of the base, and the bottom end face of the base support tube is flush with the bottom end face of the base positioning sleeve.

[0006] Preferably, a guide block limiting sleeve is coaxially provided on the guide block positioning hole, and the guide block limiting sleeve is used for the set screw positioning head of the set screw to be fitted into.

[0007] Preferably, the guide block limiting sleeve has a diameter of DN80mm, a length of 50mm, and a wall thickness of 8mm.

[0008] Preferably, the base positioning sleeve has a diameter of DN80mm, a length of 20mm, and a wall thickness of 8mm.

[0009] Preferably, there are two base support tubes.

[0010] Preferably, the base support tube has a diameter of DN20mm, a length of 20mm, and a wall thickness of 4mm.

[0011] Preferably, the base positioning sleeve, the base support tube, and the guide block limiting sleeve are all made of metal tubes.

[0012] Preferably, the guide block positioning hole and the guide block limiting sleeve are fixed by welding, the base positioning hole and the base positioning sleeve are fixed by welding, and the base support tube is fixed by welding to the base.

[0013] Preferably, the welded ends of the guide block limiting sleeve and the base positioning sleeve are both chamfered.

[0014] Preferably, the chamfer is 60°.

[0015] The present invention achieves the following technical advantages over the prior art: In this utility model of a loading device for a medium-speed coal mill, a base positioning sleeve and a base support tube are added to the bottom of the base. The base positioning sleeve is coaxially arranged with the base positioning hole, and the bottom end face of the base support tube is flush with the bottom end face of the base positioning sleeve. In this way, the bottom end face of the base support tube and the bottom end face of the base positioning sleeve are on the same plane, so that when the base is placed on the pressure ring, the base and the pressure ring always remain in a horizontal state, ensuring that the sleeve hole of the guide rod and the upper guide block remain concentric. During operation, the loading device will not be tilted, avoiding accelerated wear of the guide rod and the upper guide block. This solves the problem of existing medium-speed coal mills, especially ZQM158 or ZQM178 medium-speed coal mills, where the loading device is tilted during operation, leading to accelerated wear of the loading device or the entire loading device tilting, causing the coal mill to jam and stop, or even the grinding ring to break, resulting in serious consequences. This avoids the hidden dangers to the safe and stable operation of the entire boiler.

[0016] Compared with the prior art, the other technical solutions of this utility model have also achieved the following technical effects: In this utility model of a medium-speed coal mill loading device, a guide block limiting sleeve is added to the guide block positioning hole, and a base positioning sleeve is added to the base positioning hole. In this way, even if the wear size of the grinding ring and steel ball decreases, the loading top screw will not detach from the guide block positioning hole of the upper guide block, causing the loading device to tip over. The increased groove depth also makes it less likely to fall off even if the loading bolts loosen and the steel ball wears less, thus avoiding the risk of the coal mill jamming and stopping, or even equipment damage accidents such as grinding ring breakage. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained by analyzing these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of the loading device for the medium-speed coal mill in this embodiment of the present invention; Figure 2 This is an exploded structural diagram of the loading device for a medium-speed coal mill in an embodiment of this utility model; Figure 3 This is a bottom view of the base structure in an embodiment of the present utility model; Figure 4 This is a top view of the upper guide block in an embodiment of the present utility model. Figure 5 This is a top-view perspective view of the base structure in an embodiment of the present utility model. Figure 6 This is a bottom-view three-dimensional structural diagram of the upper guide block in an embodiment of this utility model.

[0019] Explanation of reference numerals in the attached figures: 1. Base; 11. Base positioning hole; 12. Base positioning sleeve; 13. Base support tube; 2. Guide rod; 3. Upper guide block; 31. Sleeve hole; 32. Guide block positioning hole; 33. Guide block limiting sleeve; 4. Spring; 5. Pressure ring; 51. Pressure ring positioning head; 6. Set screw; 61. Set screw positioning head. Detailed Implementation

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

[0021] The purpose of this utility model is to provide a loading device for a medium-speed coal mill to solve the problems existing in the prior art: to solve the problem that the loading device of existing medium-speed coal mills, especially ZQM158 or ZQM178, is tilted during operation, which leads to accelerated wear of the loading device or the entire loading device tilting over, causing the coal mill to jam and stop operating, or even the grinding ring to break, thus avoiding the hidden dangers to the safe and stable operation of the entire boiler.

[0022] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] like Figures 1 to 6 As shown, this embodiment provides a loading device for a medium-speed coal mill, including a base 1, guide rods 2, an upper guide block 3, and a spring 4. A hemispherical base positioning hole 11 is provided at the center of the bottom of the base 1, which is used to cooperate with the hemispherical pressure ring positioning head 51 of the pressure ring 5. Two guide rods 2 are fixedly provided on the top of the base 1, and the two guide rods 2 are arranged vertically. Each guide rod 2 is fitted with a spring 4. The upper guide block 3 has two fitting holes 31 for fitting onto the two guide rods 2 respectively. The diameter of the fitting holes 31 is smaller than the outer diameter of the spring 4. A hemispherical guide block positioning hole 32 is provided at the center of the top of the upper guide block 3, which is used to cooperate with the hemispherical top screw positioning head 61 of the top screw 6. The threaded section of the top screw 6 is threadedly connected to the mill chamber.

[0024] The improvement lies in the following: a base positioning sleeve 12 is coaxially fixed to the base positioning hole 11. The base positioning sleeve 12 is used to fit onto the pressure ring positioning head 51. A base support tube 13 is provided on one end of the base 1 in the length direction. The base support tube 13 is symmetrically arranged along the midpoint of the width direction of the base 1. The bottom end face of the base support tube 13 is flush with the bottom end face of the base positioning sleeve 12. In this way, the bottom end face of the base support tube 13 and the bottom end face of the base positioning sleeve 12 are located on the same plane. This ensures that when the base 1 is placed on the pressure ring 5, the base 1 and the pressure ring 5 always remain horizontal under the support of the base support tube 13 and the base positioning sleeve 12. This ensures that the fitting hole 31 of the guide rod 2 and the upper guide block 3 remains concentric, and the loading device will not tilt during operation, thus avoiding accelerated wear of the guide rod 2 and the upper guide block 3.

[0025] In one embodiment, a guide block limiting sleeve 33 is coaxially provided on the guide block positioning hole 32, and the guide block limiting sleeve 33 is used for the top screw positioning head 61 of the top screw 6 to be fitted into. Currently, because the guide block positioning hole 32 of the loading device is too shallow, after the coal mill has been running for a period of time, as the steel balls and grinding ring wear elements wear, the diameter of the upper grinding ring, lower grinding ring, and steel balls will shrink, and the spring 4 will gradually loosen. This will cause the top screw 6 to disengage from the guide block positioning hole 32 of the loading device, causing the entire loading device to tilt. In mild cases, this will cause the coal mill to jam and stop operating; in severe cases, it will cause the grinding ring to break. After installing a guide block limiting sleeve 33 on the guide block positioning hole 32 and a base positioning sleeve 12 on the base positioning hole 11, the loading top screw 6 will not disengage from the guide block positioning hole 32 of the upper guide block 3 and cause the loading device to tip over, even if the wear size of the grinding ring and steel ball decreases. The increased groove depth will also prevent the loading bolt from loosening and the steel ball from falling off easily, thus avoiding the risk of equipment damage accidents such as the coal mill jamming and shutdown or even the grinding ring breaking.

[0026] In one embodiment, the guide block limiting sleeve 33 has a diameter of DN80mm, a length of 50mm, and a wall thickness of 8mm.

[0027] In one embodiment, the base positioning sleeve 12 has a diameter of DN80mm, a length of 20mm, and a wall thickness of 8mm.

[0028] In one embodiment, there are two base support tubes 13.

[0029] In one embodiment, the base support tube 13 has a diameter of DN20mm, a length of 20mm, and a wall thickness of 4mm.

[0030] In one embodiment, the base positioning sleeve 12, the base support tube 13, and the guide block limiting sleeve 33 are all made of metal tubes, such as steel tubes.

[0031] In one embodiment, the guide block positioning hole 32 and the guide block limiting sleeve 33 are fixed by welding, the base positioning hole 11 and the base positioning sleeve 12 are fixed by welding, and the base support tube 13 is fixed by welding to the base 1.

[0032] In one embodiment, the welded ends of the guide block limiting sleeve 33 and the base positioning sleeve 12 are both chamfered.

[0033] In one embodiment, the chamfer is 60°.

[0034] In one embodiment, the specific modification process is as follows: In one embodiment, the base 1 has a trapezoidal structure. The upper bottom surface of the base 1 faces downward and the lower bottom surface faces upward. The base positioning hole 11, the base positioning sleeve 12, and the base support tube 13 are disposed on the upper top surface of the base 1.

[0035] In one embodiment, the upper guide block 3 includes a trapezoidal structure and two sleeves. The upper bottom surface of the trapezoidal structure faces upward and the lower bottom surface faces downward. A guide block positioning hole 32 and a guide block limiting sleeve 33 are provided on the upper bottom surface. The trapezoidal structure has two holes, and the two sleeves are coaxially arranged at the two holes, forming two sleeve holes 31. The diameter of the sleeve hole 31 is larger than that of the guide rod 2 to ensure smooth sliding, but the diameter of the sleeve hole 31 is smaller than that of the spring 4 to ensure that the spring 4 can be compressed.

[0036] Modifications and optimizations were carried out without altering the overall performance and structure of the original loading device: Step 1: Based on the original loading device base positioning hole 11 and guide block positioning hole 32, both being DN80mm in diameter, select a DN80mm pipe with an 8mm wall thickness and process short pipes of 50mm and 20mm lengths respectively. The DN80mm 50mm short pipe has one end chamfered at a 60-degree angle. The DN80mm 20mm short pipe also has one end chamfered at a 60-degree angle. Simultaneously, select a DN20mm pipe with a 4mm wall thickness and process a 20mm long short pipe.

[0037] Step 2: Fix a short pipe with a length of 50mm and a diameter of DN80mm onto the guide block positioning hole 32. When fixing, ensure that the guide block positioning hole 32 and the chamfered end of the short pipe are concentric and perform multiple welds to form the guide block limiting sleeve 33. Fix a short pipe with a diameter of DN80mm and a diameter of 20mm onto the base positioning hole 11. Ensure that the base positioning hole 11 and the chamfered end of the short pipe are concentric and perform multiple welds to form the base positioning sleeve 12. Fix short pipes with a diameter of DN20mm and a diameter of 20mm onto one end of the base 1 along its length and weld them symmetrically at the midpoint of the width direction to form the base support pipe 13.

[0038] The technical problem to be solved by the loading device for this medium-speed coal mill is: This solution addresses the issue of misalignment of the loading device in existing ZQM158 or ZQM178 coal mills during operation. This misalignment can lead to accelerated wear of the loading device, complete tilting, mill jamming, or even grinding ring breakage, posing a serious threat to the safe and stable operation of the entire boiler. Such an accident not only wastes equipment parts and costs (upper grinding ring: 40,000 RMB, lower grinding ring: 50,000 RMB) but also significantly increases the workload for maintenance personnel (replacing a single grinding ring requires five people and five days).

[0039] The beneficial effects of this medium-speed coal mill loading device have been verified: Before the improvement: Due to the unreasonable installation structure of the coal mill loading device, the loading device was prone to tilting, accelerating the wear of the guide rod and upper guide block. Every 3000 hours of operation, the entire worn loading device needed repair or replacement, increasing the workload of maintenance personnel and wasting material costs. Because of the unreasonable installation structure of the loading device, specifically the shallow depth of the top screw positioning hole, the grinding ring and steel balls would shrink after wear, causing the top screw to detach from the loading device, leading to the loading device tipping over. This could result in the coal mill jamming and stopping, or even serious equipment damage such as grinding ring breakage.

[0040] After the improvement: Previously, the coal mill required repair or replacement of all six loading units every 3000 hours of cumulative operation. Now, the repair or replacement of the entire loading unit is delayed until 5000 hours of safe and stable operation, reducing the replacement frequency of the loading units and decreasing the workload of maintenance personnel and material consumption costs. Furthermore, there have been no longer any equipment damage accidents caused by the coal mill loading unit tipping over, resulting in the coal mill jamming and shutdown, or even the grinding ring breaking, ensuring the safe and stable operation of the boiler.

[0041] This utility model uses specific examples to illustrate its principles and implementation methods. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the idea of ​​this utility model. In summary, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A loading device for a medium-speed coal mill, comprising a base, guide rods, an upper guide block, and springs, wherein the bottom of the base is provided with a hemispherical base positioning hole for engaging with a hemispherical pressure ring positioning head of a pressure ring, two vertically arranged guide rods are fixedly provided on the top of the base, each guide rod being fitted with a spring, the upper guide block is provided with two fitting holes for fitting onto the guide rods, and the top of the upper guide block is provided with a hemispherical guide block positioning hole for engaging with a hemispherical set screw positioning head of a set screw, characterized in that: A base positioning sleeve is coaxially fixed to the base positioning hole. The base positioning sleeve is used to fit onto the pressure ring positioning head. A base support tube is provided at one end of the base in the length direction. The base support tube is symmetrically arranged along the midpoint of the width direction of the base. The bottom end face of the base support tube is flush with the bottom end face of the base positioning sleeve.

2. The loading device for a medium-speed coal mill according to claim 1, characterized in that: A guide block limiting sleeve is coaxially provided on the guide block positioning hole, and the guide block limiting sleeve is used for the set screw positioning head of the set screw to be fitted into.

3. The loading device for a medium-speed coal mill according to claim 2, characterized in that, The guide block limiting sleeve has a diameter of DN80mm, a length of 50mm, and a wall thickness of 8mm.

4. The loading device for a medium-speed coal mill according to claim 1 or 3, characterized in that: The base positioning sleeve has a diameter of DN80mm, a length of 20mm, and a wall thickness of 8mm.

5. The loading device for a medium-speed coal mill according to claim 1, characterized in that: There are two base support tubes.

6. The loading device for a medium-speed coal mill according to claim 1 or 5, characterized in that: The base support tube has a diameter of DN20mm, a length of 20mm, and a wall thickness of 4mm.

7. The loading device for a medium-speed coal mill according to claim 3, characterized in that: The base positioning sleeve, the base support tube, and the guide block limiting sleeve are all made of metal tubes.

8. The loading device for a medium-speed coal mill according to claim 7, characterized in that: The guide block positioning hole and the guide block limiting sleeve are fixed by welding, the base positioning hole and the base positioning sleeve are fixed by welding, and the base support tube is fixed by welding to the base.

9. The loading device for a medium-speed coal mill according to claim 8, characterized in that: Both the guide block limiting sleeve and the base positioning sleeve have chamfered ends.

10. The loading device for a medium-speed coal mill according to claim 9, characterized in that: The chamfer is 60°.

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