Connecting structure for boiler material returning pipe

Abstract

The utility model discloses a connecting structure for a boiler material returning pipe, which comprises the material returning pipe and an inserting cylinder which are respectively arranged on a boiler, the material returning pipe and the inserting cylinder are arranged in an inner and outer nesting mode and are partially overlapped, and the outer wall of the material returning pipe and the outer wall of the inserting cylinder are mutually connected through a bellow expansion joint. A first protection layer and a second protection layer are arranged outside the material returning pipe and the inserting cylinder respectively, a mounting groove is formed between the first protection layer and the second protection layer, the bellow expansion joint is located in the mounting groove, and the two ends of the bellow expansion joint are connected with the first protection layer and the second protection layer respectively; the first protection layer and the second protection layer are the same in structure and comprise protection pipes arranged outside the material returning pipe or the inserting cylinder in a sleeving mode, the inner sides of the protection pipes are filled with first heat preservation cotton layers, and a plurality of first baffles are annularly distributed at the two ends of the inner walls of the protection pipes. The first baffles are located on the outer sides of the two ends of the first heat preservation cotton layer and used for limiting the first heat preservation cotton layer. According to the utility model, the corrosion damage of the connecting part of the material returning pipe in the use process can be effectively relieved.

Description

Technical Field

[0001] The utility model relates to a boiler return structure, in particular to a connection structure for a boiler return pipe. Background Art

[0002] During the production process of a boiler, small particulate fuels are discharged together with the flue gas. Therefore, current manufacturers will install a filtering mechanism and a return pipe in the boiler, that is, use the filtering mechanism to separate the fuel particles in the flue gas, and the separated fuel particles are returned to the filter through the return pipe, so as to achieve the full utilization of the fuel. On this basis, since the return pipe near the boiler end is affected by the furnace temperature and undergoes thermal expansion and contraction, in order to prevent the return pipe from cracking due to thermal expansion and contraction, manufacturers will use an expansion structure for protection, that is, a socket is sleeved at the end of the return pipe, and the end of the socket extends to the outside of the return pipe and is welded to the boiler. The return pipe and the socket are connected to each other through a corrugated expansion joint. Thus, when the socket undergoes thermal expansion and contraction, it can effectively prevent the return pipe from being stressed and cracked, and use the corrugated expansion joint to ensure its sealing effect.

[0003] However, the defect of this structure is that since the fuel and its flue gas contain sulfur, when the fuel particles return to the boiler with the flue gas, they will corrode the side wall of the return pipe, and after the return pipe has a corrosion break, it will impact the external corrugated expansion joint, resulting in corrosion damage to its connection part. And the existing expansion structure cannot overcome this technical problem.

[0004] Therefore, a connection structure for a boiler return pipe with good anti-corrosion effect is needed. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a connection structure for a boiler return pipe. It can effectively alleviate the corrosion damage of the connection part of the return pipe during use.

[0006] The technical solution of the utility model: A connection structure for a boiler return pipe, including a return pipe and a socket respectively arranged on the boiler. The return pipe and the socket are arranged in an inner and outer nested manner and partially overlap. The outer walls of the return pipe and the socket are connected to each other through a corrugated expansion joint. First protective layers and second protective layers are respectively arranged outside the return pipe and the socket. An installation groove is formed between the first protective layer and the second protective layer. The corrugated expansion joint is located in the installation groove and is connected to the first protective layer and the second protective layer at both ends respectively; the structures of the first protective layer and the second protective layer are the same, including a protective pipe sleeved outside the return pipe or the socket. The inner side of the protective pipe is filled with a first heat-insulating cotton layer. A plurality of first baffles are annularly distributed at both ends of the inner wall of the protective pipe. The first baffles are located outside both ends of the first heat-insulating cotton layer.

[0007] In the above-mentioned connecting structure for a boiler return pipe, an annular second baffle is provided outside the return pipe or the insertion cylinder. The second baffle is located on the outer sides of both ends of the first heat-insulating cotton layer and is used to limit the first heat-insulating cotton layer. The second baffle and the first baffle are radially offset from each other inside and outside.

[0008] In the above-mentioned connecting structure for a boiler return pipe, an inner sleeve is detachably connected to the end of the return pipe. The end of the inner sleeve extends to the inside of the return pipe and forms a receiving cavity between the inner wall of the return pipe. The receiving cavity is filled with a second heat-insulating cotton layer.

[0009] In the above-mentioned connecting structure for a boiler return pipe, one end of the inner sleeve is bolted to the end of the return pipe through a flange. The other end of the inner sleeve extends into the return pipe and is connected with a bent portion. There is a gap between the end of the bent portion and the inner wall of the return pipe.

[0010] In the above-mentioned connecting structure for a boiler return pipe, a stepped groove is formed between the second baffle and the protection pipe. The end of the corrugated expansion joint extends into the stepped groove to connect with the second baffle. The stepped groove is filled with a sealing filler, and the sealing filler is used to seal the connection gap between the protection pipe and the corrugated expansion joint.

[0011] Compared with the prior art, the present utility model has the following characteristics:

[0012] (1) By defining the structures of the first protective layer and the second protective layer, the first protective layer and the second protective layer can respectively wrap and protect the return pipe and the insertion cylinder from the outside, thereby effectively preventing the connection part from generating a break after being corroded and improving the return stability of the return pipe. On this basis, through the structural cooperation of the first baffle and the second baffle, on the one hand, it can fix the protection pipe and the first heat-insulating cotton layer and avoid the offset of the first protective layer and the second protective layer; on the other hand, it can also prevent the damage caused by the return pipe or the insertion cylinder to the protection pipe after thermal expansion and contraction, and improve the structural stability of the present utility model;

[0013] (2) Through the structural cooperation of the inner sleeve and the second heat-insulating cotton layer, it can also protect the return pipe at the interval between the first protective layer and the second protective layer, that is, prevent the flue gas from impacting the external corrugated expansion joint after passing through the return pipe, and further improve the anti-corrosion effect of the present utility model;

[0014] (3) Through the structural cooperation of the stepped groove and the sealing filler, it can seal the connection part after the corrugated expansion joint is installed, thereby preventing the flue gas in the return pipe from overflowing from the connection gap;

[0015] Therefore, the present utility model can effectively alleviate the corrosion damage of the connection part of the return pipe during use. Description of the Drawings

[0016] Figure 1 is the structural schematic diagram of the present utility model;

[0017] Figure 2 is Figure 1 the sectional view taken along the direction A of

[0018] The reference signs in the drawings are: 1 - return pipe, 2 - insertion cylinder, 3 - corrugated expansion joint, 4 - first protective layer, 5 - second protective layer, 6 - protective pipe, 7 - first heat-insulating cotton layer, 8 - first baffle, 9 - second baffle, 10 - inner sleeve, 11 - second heat-insulating cotton layer, 12 - sealing packing. Specific embodiments

[0019] The present utility model will be further described below in conjunction with the drawings and embodiments, but it shall not be used as a basis for limiting the present utility model.

[0020] Embodiment. A connecting structure for a boiler return pipe, the structure is as Figure 1 shown, including a return pipe 1 and an insertion cylinder 2 respectively arranged on the boiler. The return pipe 1 and the insertion cylinder 2 are arranged in an inner and outer nested manner and partially overlap. The outer walls of the return pipe 1 and the insertion cylinder 2 are connected to each other through a corrugated expansion joint 3. The outer parts of the return pipe 1 and the insertion cylinder 2 are respectively provided with a first protective layer 4 and a second protective layer 5. An installation groove is formed between the first protective layer 4 and the second protective layer 5. The corrugated expansion joint 3 is located in the installation groove and is connected to the first protective layer 4 and the second protective layer 5 at both ends respectively; the structures of the first protective layer 4 and the second protective layer 5 are the same, including a protective pipe 6 sleeved outside the return pipe 1 or the insertion cylinder 2. The inner side of the protective pipe 6 is filled with a first heat-insulating cotton layer 7. The first heat-insulating cotton layer 7 is used to wrap and protect the return pipe 1 or the insertion cylinder 2. A plurality of first baffles 8 are annularly distributed at both ends of the inner wall of the protective pipe 6. The first baffles 8 are located outside both ends of the first heat-insulating cotton layer 7.

[0021] An annular second baffle 9 is provided outside the return pipe 1 or the insertion cylinder 2. The second baffle 9 is located outside both ends of the first heat-insulating cotton layer 7 and is used to limit the first heat-insulating cotton layer 7. The second baffle 9 and the first baffle 8 are radially offset inside and outside.

[0022] The end of the return pipe 1 is detachably connected with an inner sleeve 10. The end of the inner sleeve 10 extends to the inside of the return pipe 1 and forms a receiving cavity between the inner wall of the return pipe 1. The receiving cavity is filled with a second heat-insulating cotton layer 11. The second heat-insulating cotton layer 11 is used to wrap and protect the gap between the two first heat-insulating cotton layers 7.

[0023] One end of the inner sleeve 10 is bolted to the end of the return pipe 1 through a flange. The other end of the inner sleeve 10 extends into the return pipe 1 and is connected with a bent part. There is a gap between the end of the bent part and the inner wall of the return pipe 1.

[0024] A stepped groove is formed between the second baffle 9 and the protection tube 6. The end of the corrugated expansion joint 3 extends into the stepped groove to connect with the second baffle 9. The second baffle 9 is provided with mounting holes for connecting the expansion joint flange. The stepped groove is filled with a sealing filler 12, and the sealing filler 12 is used to seal the connection gap between the protection tube 6 and the corrugated expansion joint 3.

[0025] The working principle of the present utility model: When the present utility model is in use, fuel particles pass through the return pipe 1 and the inserting cylinder 2 in sequence with the flue gas and enter the boiler, realizing the recycling of fuel particles. When the return pipe 1 and the inserting cylinder 2 are corroded and damaged due to impact during use, the external first heat-insulating cotton layer 7 can play a protective and intercepting effect, preventing the flue gas from directly overflowing from the break, that is, ensuring the sealing performance of the connection part. Similarly, when the flue gas impacts the return pipe 1 at the installation groove position, the inner sleeve 10 and the second heat-insulating cotton layer 11 can protect the impacted part, preventing the return pipe 1 at this part from being corroded and broken after being impacted, and the problem that the flue gas overflows from the break and damages the corrugated expansion joint 3, improving the use stability of the present utility model.

Claims

1. A connecting structure for a boiler return pipe, comprising a return pipe (1) and an insertion cylinder (2) respectively arranged on the boiler. The return pipe (1) and the insertion cylinder (2) are arranged in an inner and outer nested manner and partially overlap. The outer walls of the return pipe (1) and the insertion cylinder (2) are connected to each other through a corrugated expansion joint (3), and it is characterized in that: A first protective layer (4) and a second protective layer (5) are respectively arranged outside the material return pipe (1) and the insertion cylinder (2). An installation groove is formed between the first protective layer (4) and the second protective layer (5). The corrugated expansion joint (3) is located in the installation groove and its two ends are respectively connected to the first protective layer (4) and the second protective layer (5). The first protective layer (4) and the second protective layer (5) have the same structure, including a protective pipe (6) sleeved outside the material return pipe (1) or the insertion cylinder (2). The inner side of the protective pipe (6) is filled with a first heat-insulating cotton layer (7). A number of first baffles (8) are annularly distributed at both ends of the inner wall of the protective pipe (6). The first baffles (8) are located outside both ends of the first heat-insulating cotton layer (7).

2. The connecting structure for a boiler return pipe according to claim 1, wherein: An annular second baffle (9) is arranged outside the material return pipe (1) or the insertion cylinder (2). The second baffle (9) is located outside both ends of the first heat-insulating cotton layer (7) and is used to limit the first heat-insulating cotton layer (7). The second baffle (9) and the first baffle (8) are radially offset from each other inside and outside.

3. A connecting structure for a boiler return pipe according to claim 1, characterized in that: An inner sleeve (10) is detachably connected to the end of the material return pipe (1). The end of the inner sleeve (10) extends to the inside of the material return pipe (1) and a receiving cavity is formed between the end of the inner sleeve (10) and the inner wall of the material return pipe (1). The receiving cavity is filled with a second heat-insulating cotton layer (11).

4. A connecting structure for a boiler return pipe according to claim 3, characterized in that: One end of the inner sleeve (10) is bolted to the end of the material return pipe (1) through a flange. The other end of the inner sleeve (10) extends into the material return pipe (1) and is connected with a bent part. A gap is left between the end of the bent part and the inner wall of the material return pipe (1).

5. A connection structure for a boiler return pipe according to claim 2, characterized in that: A step groove is formed between the second baffle (9) and the protective pipe (6). The end of the corrugated expansion joint (3) extends into the step groove to connect the second baffle (9). A sealing filler (12) is filled in the step groove. The sealing filler (12) is used to seal the connection gap between the protective pipe (6) and the corrugated expansion joint (3).

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