A pulverized coal injection pipe

Abstract

This utility model belongs to the field of rotary kiln technology and discloses a pulverized coal injection pipe, including a pulverized coal injection pipe body and prefabricated components disposed outside the pulverized coal injection pipe body. The prefabricated components are annular, and there are several prefabricated components, with adjacent prefabricated components spliced ​​together by a casting layer. The circumference of the prefabricated component is 150mm, and the inner diameter of the prefabricated component is 5mm larger than the outer diameter of the pulverized coal injection pipe body. The prefabricated component closest to the head of the pulverized coal injection pipe body is more than 50mm beyond the head of the pulverized coal injection pipe body. A ring is provided at the rear end of the prefabricated component, and an anchor is provided inside the ring. The anchor includes a fixing rod and symmetrically arranged anchor hooks. One end of the anchor hook is fixedly connected to the fixing rod, and the free end of the fixing rod is fixedly connected to the outer wall of the pulverized coal injection pipe body. The anchor hook is used to anchor the ring. This solution reduces the number of gaps between the prefabricated components by setting several annular prefabricated components and splicing adjacent prefabricated components together by a casting layer. This utility model solves the problem of excessive gaps in existing pulverized coal injection pipe prefabricated components.

Description

Technical Field

[0001] This solution belongs to the field of rotary kiln technology, specifically involving a pulverized coal injection pipe. Background Technology

[0002] As a core component of rotary kilns, pulverized coal injection pipes are widely used in industries such as building materials, metallurgy, and chemicals to generate high-temperature environments within the kiln. The front end of the pulverized coal injection pipe is constantly exposed to a high-temperature airflow of approximately 1200℃. Its 80mm thick protective castable refractory layer must withstand not only the intense erosion from the high-temperature, dust-laden airflow but also drastic temperature changes. Under these conditions, the castable refractory is highly susceptible to erosion, wear, cracking, and spalling. The damage is most severe closer to the head of the pulverized coal injection pipe (0-2 meters inside the rotary kiln), exhibiting a gradual burning-out phenomenon from the inside out.

[0003] When the refractory material at the head of the pulverized coal injection pipe burns out, exposing the metal outer wall, it constitutes a major equipment hazard and requires immediate repair. The repair method involves removing the pulverized coal injection pipe, erecting a platform, removing any remaining refractory material, re-welding the anchors, and setting up a mold for re-pouring. If one section of refractory material is burned, the entire circumference must be removed and re-cast. This method involves a large workload, and after pouring, a curing period is required before demolding. The entire repair process requires at least two shifts (16 hours or more), resulting in significant economic losses for the company due to kiln shutdown and production stoppage. Some factories with the resources may replace the pulverized coal injection pipe with a spare. However, spare pipes typically weigh up to 8 tons, requiring large lifting equipment, and the disassembly and reassembly process is complex. Nighttime operations pose safety hazards, and reconnecting the two flexible metal hoses at the tail end is labor-intensive, with poor sealing at the joints potentially leading to ash leakage. Replacing a spare pulverized coal injection pipe usually requires one 8-hour daytime shift, also presenting the problems of a large workload and high cost.

[0004] See the existing publication (announcement) number CN103629686A for a prefabricated pulverized coal injection pipe, which includes at least two prefabricated body sections for splicing into a prefabricated pulverized coal injection pipe. The prefabricated body section includes at least two splice blocks for splicing into a prefabricated body section. A splice joint is formed between two adjacent splice blocks. The splice joints on two adjacent prefabricated body sections are staggered.

[0005] The aforementioned precast pulverized coal injection pipe includes at least two precast body sections for splicing into a precast pulverized coal injection pipe. The precast body is composed of multiple blocks, meaning that a single precast component is a precast body composed of multiple blocks. However, this results in multiple gaps in the precast body, which makes it easier for high-temperature airflow and dust to enter. At the same time, the multiple splicing steps increase the workload of construction, require more construction time, and may result in human error during the splicing process, affecting the overall performance of the precast component. Utility Model Content

[0006] The purpose of this solution is to provide a pulverized coal injection pipe to address the problem of excessive gaps in existing pulverized coal injection pipe prefabrication components.

[0007] To achieve the above objectives, this solution provides a pulverized coal injection pipe, including a pulverized coal injection pipe body and prefabricated components disposed outside the pulverized coal injection pipe body. The prefabricated components are annular prefabricated components, and there are several prefabricated components, with adjacent prefabricated components spliced ​​together by a casting layer.

[0008] The principle and effect of this solution are as follows: by setting up several annular prefabricated components and splicing adjacent prefabricated components through a casting layer, the number of gaps between the prefabricated components is reduced. The annular prefabricated components themselves are relatively complete, and the adjacent prefabricated components are tightly connected through the casting layer to form a relatively continuous whole, which reduces the intrusion of high-temperature airflow and dust, improves the high-temperature resistance and wear resistance of the pulverized coal injection pipe, and extends the service life of the equipment.

[0009] Furthermore, the prefabricated component is located at the head of the pulverized coal injection pipe body, the prefabricated component has a circumference of 150mm, and the inner diameter of the prefabricated component is 5mm larger than the outer diameter of the pulverized coal injection pipe body.

[0010] The principle and effect of this solution are as follows: by placing the prefabricated component at the head of the pulverized coal injection pipe body, and designing the prefabricated component as a ring with a circumference of 150mm and an inner diameter 5mm larger than the outer diameter of the pulverized coal injection pipe body, the prefabricated component is tightly fitted to the pulverized coal injection pipe body, reducing the gaps between the prefabricated components.

[0011] Furthermore, the precast component closest to the head of the pulverized coal injection pipe body exceeds 50mm from the head of the pulverized coal injection pipe body.

[0012] The principle and effect of this scheme are as follows: by setting the precast component closest to the head of the pulverized coal injection pipe body to be 50mm beyond the head of the pulverized coal injection pipe body, a buffer zone is formed, so that there is a certain gap between the precast component and the pulverized coal injection pipe body, reducing the direct impact of high-temperature airflow and dust on the head of the pulverized coal injection pipe body, and reducing the heat transfer between the precast component and the pulverized coal injection pipe body.

[0013] Furthermore, the rear end of the precast component is provided with a ring, and an anchor is provided inside the ring. The anchor includes a fixing rod and symmetrically arranged anchor hooks. One end of the anchor hook is fixedly connected to the fixing rod, and the free end of the fixing rod is fixedly connected to the outer wall of the pulverized coal pipe body. The anchor hook is used to anchor the ring.

[0014] The principle and effect of this solution are as follows: by setting a ring at the rear end of the precast component and setting anchors inside the ring, the anchors include a fixing rod and symmetrically arranged anchor hooks. One end of the anchor hook is fixedly connected to the fixing rod, and the free end of the fixing rod is fixedly connected to the outer wall of the pulverized coal injection pipe body. The anchor hooks firmly grasp the ring, so that the precast component and the pulverized coal injection pipe body are tightly combined, which enhances the stability and firmness of the connection.

[0015] Furthermore, it also includes a filling assembly disposed within the anchor, the filling assembly comprising a filling chamber and a piercing needle, the anchor having a through hole and a cavity, the through hole communicating with the cavity and being disposed below the cavity, the filling chamber being disposed within the cavity, the filling chamber being a flexible chamber, the filling chamber containing a filler; the piercing needle being used to pierce the filling chamber, the piercing needle being provided with a driving unit for driving the piercing needle to pierce the filling chamber.

[0016] The principle and effect of this scheme are as follows: (1) Anchors are usually made of heat-resistant steel, which has a large coefficient of thermal expansion, while the coefficient of thermal expansion of the castable is relatively small. In high-temperature environments, anchors will expand more than castables after being heated. For example, a 15mm long anchor will have a radial expansion of about 0.28mm at 1000℃. If the expansion joint size reserved during construction is smaller than the radial expansion of the anchor, the expansion of the anchor will compress the castable, causing cracks in the castable or gaps to form between the anchor and the anchor. Therefore, it is necessary to fill the gap between the anchor and the castable to avoid the cracks from increasing. (2) When the anchor expands due to heat and a gap is formed between it and the castable, the driving unit drives the piercing needle to pierce the filling chamber, so that the filler flows out from the through hole and fills the gap between the anchor and the castable, thereby enhancing the tight connection between the anchor and the castable.

[0017] Furthermore, the driving unit is a shape memory metal, one end of which is fixedly connected to the cavity and the free end is fixedly connected to the piercing needle. When heated, the shape memory metal is used to drive the piercing needle to pierce the filling cavity.

[0018] The principle and effect of this solution are as follows: the shape memory metal expands when heated, driving the piercing needle to move towards the filling chamber and pierce the filling chamber, so that the filling material in the filling chamber flows out through the through hole and finally flows into the gap between the anchor and the casting material.

[0019] Furthermore, the driving unit includes a spring, a first hook, and a second hook. One end of the spring is fixedly connected to the piercing needle, and the free end is fixedly connected to the cavity. The piercing needle is fixedly connected to the first hook, and the second hook is fixedly disposed in the cavity. The second hook is configured to cooperate with the first hook. The second hook is a second hook that melts when heated.

[0020] The principle and effect of this scheme are as follows: In the initial state, the spring is in a compressed state, and the first hook is locked by the second hook. When the pulverized coal pipe is heated, the second hook melts, the first hook loses the restriction of the second hook, and under the drive of the spring preload, the piercing needle moves towards the filling chamber and pierces the filling chamber, allowing the filling material in the filling chamber to flow out through the through hole, and finally flow into the gap between the anchor and the casting material.

[0021] Furthermore, a guide groove is provided inside the cavity, and the first hook is slidably disposed in the guide groove.

[0022] The principle and effect of this solution are as follows: the guide groove is used to provide positioning and guidance for the movement of the first hook, so as to prevent it from dislodging or slipping during the movement process.

[0023] Furthermore, a groove is provided inside the cavity, which is used to guide the puncture needle to move towards the filling chamber, and the puncture needle is slidably connected to the groove.

[0024] The principle and effect of this solution are as follows: the groove is used to provide positioning and guidance for the movement of the puncture needle, so as to prevent dislocation or slippage during its movement.

[0025] Furthermore, the number of filling components is three sets, and they are respectively located in the fixing rod and the two anchor hooks.

[0026] The principle and effect of this solution are as follows: since there may be gaps between the fixing rod and the two anchor hooks and the casting material, filling components are set in the fixing rod and the two anchor hooks. Attached Figure Description

[0027] Figure 1 This is a cross-sectional view of a front view of a pulverized coal injection pipe according to this utility model; Figure 2 This is a cross-sectional view of a pulverized coal injection pipe according to the present invention. Figure 3 This is a schematic diagram of the internal structure of the anchor of this utility model. Figure 1 ; Figure 4 for Figure 3 Enlarged view of point A in the middle; Figure 5 This is a schematic diagram of the internal structure of the anchor of this utility model. Figure 2 ; Figure 6 for Figure 5 A magnified view of point B in the middle.

[0028] The corresponding labels in the attached drawings are named as follows: 1. Coal injection pipe body; 2. Precast component; 3. Ring; 4. Anchor nail; 41. Through hole; 42. Cavity; 421. Slide groove; 43. Fixing rod; 44. Anchor hook; 5. Filling assembly; 51. Filling chamber; 52. Puncture needle; 53. Shape memory metal; 54. Spring; 55. First hook; 56. Second hook. Detailed Implementation

[0029] The following will describe the concept and technical effects of this utility model clearly and completely with reference to the embodiments, so as to fully understand the purpose, features and effects of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are all within the scope of protection of this utility model. Example 1: Please see Figure 1 and Figure 2 A pulverized coal injection pipe includes a pulverized coal injection pipe body 1 and prefabricated components 2 disposed outside the pulverized coal injection pipe body 1. The prefabricated components 2 are disposed at the head of the pulverized coal injection pipe body 1. The circumference of the prefabricated components 2 is 150 mm. The inner diameter of the prefabricated components 2 is 5 mm larger than the outer diameter of the pulverized coal injection pipe body 1. The prefabricated components 2 closest to the head of the pulverized coal injection pipe body 1 are 50 mm beyond the head of the pulverized coal injection pipe body 1, so as to facilitate the assembly of the prefabricated components 2 with the pulverized coal injection pipe body 1. The prefabricated components 2 are annular prefabricated components 20 in number, and adjacent prefabricated components 2 are spliced ​​together by a casting layer. The casting layer uses a casting material that is high alumina, mullite, silicon carbide, or zirconium silicate refractory castable with a density of 2.4 to 2.6 g / cm³ and a thermal expansion coefficient of 6 × 10 K at 1200 °C.

[0030] The rear end of the precast component 2 is provided with a ring 3, which is a ring for supporting refractory castable. An anchor 4 is provided inside the ring 3. The anchor 4 includes a fixing rod 43 and symmetrically arranged anchor hooks 44. One end of the anchor hook 44 is fixedly connected to the fixing rod 43, and the free end of the fixing rod 43 is fixedly connected to the outer wall of the pulverized coal injection pipe body 1. The anchor hook 44 is used to anchor the ring 3.

[0031] Specific working principle: (1) Fabrication of precast component 2: The 3-meter section of the head of the pulverized coal pipe body 1 is made into 20 ring-shaped precast components 2, each ring is 150mm long, and the inner ring diameter is 5mm larger than the outer diameter of the pulverized coal pipe body 1 to ensure assembly fit. The material of precast component 2 is ultra-high temperature corundum mullite high-strength refractory castable. The inner ring of precast component 2 is set with circularly distributed heat-resistant steel nails. In normal times, these precast components 2 are mass-produced by molds, and the quality of each piece is strictly controlled as spare parts for emergency repair. (2) Emergency repair process: When the pulverized coal pipe body 1 is burned and needs emergency repair, first stop the kiln, stop the material and stop the fire, and quickly remove the pulverized coal pipe body 1 from the kiln head cover. After cooling slightly, knock the precast component 2 of the burned part that has peeled off. Since the burn is more serious closer to the head, keep peeling off until the whole ring is completely intact. Then clean the metal outer surface of the pulverized coal pipe body 1 and apply high temperature adhesive refractory mud evenly. Next, the spare precast part 2 is sequentially fitted onto the pulverized coal injection pipe body 1, and adhesive refractory mortar is applied to the contact surface between adjacent precast parts 2 until the precast part 2 extends 50mm beyond the original length to the end of the pulverized coal injection pipe body 1.

[0032] Example 2: The differences between this embodiment and the previous embodiment are as follows: Please see Figures 3-6 To avoid gaps between the anchor bolt 4 and the casting material, a filling component 5 is provided inside the anchor bolt 4. There are three sets of filling components 5, located in the fixing rod 43 and the two anchor hooks 44 respectively. Each filling component 5 includes a filling chamber 51 and a piercing needle 52. The anchor bolt 4 has a through hole 41 and a cavity 42, with the through hole 41 communicating with the cavity 42 and located below the cavity 42. The filling chamber 51 is located inside the cavity 42 and is a flexible chamber containing a filler, which can be a quick-drying cement-based filler. The filling material has the characteristics of self-flowing and self-sealing, and can flow to the gap between the filling anchor 4 and the casting material; the piercing needle 52 is used to pierce the filling chamber 51. The cavity 42 is provided with a sliding groove 421, which is used to guide the piercing needle 52 to move towards the filling chamber 51. The piercing needle 52 is slidably connected to the sliding groove 421. The sliding groove 421 is used to provide positioning and guidance for the movement of the piercing needle, and to prevent it from dislodging or slipping during the movement process; the piercing needle 52 is provided with a driving unit for driving the piercing needle 52 to pierce the filling chamber 51.

[0033] The drive unit uses shape memory metal 53 (see Figure 3 and Figure 4 The shape memory metal 53 is made of Ti-50.8Ni-0.1Zr shape memory alloy. At a high temperature of 500℃, this alloy exhibits elongation properties, thereby driving the piercing needle 52 to pierce the filling chamber 51. One end of the shape memory metal 53 is fixedly connected to the cavity 42, and the free end is fixedly connected to the piercing needle 52. When heated, the shape memory metal 53 drives the piercing needle 52 to pierce the filling chamber 51. Through the elongation of the shape memory metal 53 due to heat, the piercing needle 52 moves towards the filling chamber 51 and pierces it, causing the filling material inside the filling chamber 51 to flow out through the through hole 41 and finally into the gap between the anchor 4 and the casting material.

[0034] The driving unit can preferably be a spring 54, a first hook 55, and a second hook 56. One end of the spring 54 is fixedly connected to the piercing needle 52, and the free end is fixedly connected to the cavity 42. The piercing needle 52 is fixedly connected to the first hook 55. A guide groove (not shown in the figure) is provided in the cavity. The first hook 55 is slidably disposed in the guide groove. The guide groove is used to provide positioning and guidance for the movement of the first hook 55. The second hook 56 is fixedly disposed in the cavity 42 and is configured to cooperate with the first hook 55. The second hook 56 is a second hook 56 that melts when heated and can be made of rubber.

[0035] Specific working principle: In the initial state, the spring 54 is in a compressed state and the first hook 55 is locked by the second hook 56. When the pulverized coal pipe body 1 is heated, the second hook 56 melts, the first hook 55 loses the restraint of the second hook 56, and under the drive of the pre-tightening force of the spring 54, the piercing needle 52 moves towards the filling chamber 51 and pierces the filling chamber 51, so that the filling material in the filling chamber 51 flows out through the through hole 41 and finally flows into the gap between the anchor 4 and the casting material.

[0036] The above descriptions are merely embodiments of this utility model, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of this utility model, and these should also be considered within the scope of protection of this utility model. These modifications will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application shall be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A coal injection pipe comprising a coal injection pipe body (1) and a preform (2) provided outside the coal injection pipe body (1), characterized in that, The precast component (2) is a ring-shaped precast component (2), and there are several precast components (2), and adjacent precast components (2) are spliced ​​together by a casting layer.

2. A coal injection pipe according to claim 1, characterised in that: The prefabricated component (2) is located at the head of the pulverized coal injection pipe body (1). The prefabricated component (2) has a circumference of 150 mm and an inner diameter that is 5 mm larger than the outer diameter of the pulverized coal injection pipe body (1).

3. A coal injection pipe according to claim 2, characterised in that: The precast component (2) closest to the head of the pulverized coal injection pipe body (1) is more than 50 mm away from the head of the pulverized coal injection pipe body (1).

4. A coal injection pipe according to claim 1, characterised in that: The precast component (2) has a ring (3) at its rear end. An anchor (4) is provided inside the ring (3). The anchor (4) includes a fixing rod (43) and symmetrically arranged anchor hooks (44). One end of the anchor hook (44) is fixedly connected to the fixing rod (43). The free end of the fixing rod (43) is fixedly connected to the outer wall of the pulverized coal injection pipe body (1). The anchor hook (44) is used to anchor the ring (3).

5. A coal injection pipe according to claim 4, characterised in that: It also includes a filling component (5) disposed in the anchor (4), the filling component (5) including a filling chamber (51) and a piercing needle (52), the anchor (4) having a through hole (41) and a cavity (42), the through hole (41) communicating with the cavity (42) and being disposed below the cavity (42), the filling chamber (51) being disposed in the cavity (42), the filling chamber (51) being a flexible chamber, the filling chamber (51) containing a filler; the piercing needle (52) being used to pierce the filling chamber (51), the piercing needle (52) having a driving unit for driving the piercing needle (52) to pierce the filling chamber (51).

6. A coal injection pipe according to claim 5, characterised in that: The driving unit is a shape memory metal (53). One end of the shape memory metal (53) is fixedly connected to the cavity (42), and the free end is fixedly connected to the piercing needle (52). When heated, the shape memory metal (53) is used to drive the piercing needle (52) to pierce the filling chamber (51).

7. A coal injection pipe according to claim 5, characterised in that: The driving unit includes a spring (54), a first hook (55) and a second hook (56). One end of the spring (54) is fixedly connected to the piercing needle (52), and the free end is fixedly connected to the cavity (42). The piercing needle (52) is fixedly connected to the first hook (55). The second hook (56) is fixedly disposed in the cavity (42). The second hook (56) is configured to cooperate with the first hook (55). The second hook (56) is a second hook (56) that melts when heated.

8. A coal injection pipe according to claim 7, characterised in that: The cavity is provided with a guide groove, and the first hook (55) is slidably disposed in the guide groove.

9. A pulverized coal injection pipe according to claim 7, characterized in that: The cavity (42) is provided with a groove (421), which is used to guide the puncture needle (52) to move towards the filling chamber (51). The puncture needle (52) is slidably connected to the groove (421).

10. A pulverized coal injection pipe according to claim 5, characterized in that: The number of filling components (5) is three sets, and they are respectively located in the fixing rod (43) and the two anchor hooks (44).

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