Double-layer furnace pipe for preheating section of stainless steel annealing furnace

Abstract

The utility model provides a double-layer furnace pipe for a preheating section of a stainless steel annealing furnace, which comprises an outer furnace pipe and an inner furnace pipe which are sleeved inside and outside, an annular interlayer cavity for flue gas circulation is formed, a plurality of upper runner plates are uniformly arranged at the upper part of the annular interlayer cavity along the axial direction at intervals, and a plurality of lower runner plates are obliquely arranged at the lower part of the annular interlayer cavity at intervals; the two ends of the lower runner plate are correspondingly connected with the left diagonal and the right diagonal of the two upper runner plates respectively to form a spiral runner arranged around the inner furnace pipe, and the upper runner plates and the lower runner plate are connected with the inner wall of the outer furnace pipe and the outer wall of the inner furnace pipe. Flue gas flowing time is prolonged, the heat exchange effect is improved, and energy consumption is low.

Description

Technical Field

[0001] The utility model belongs to the technical field of stainless steel bright annealing furnaces, and particularly relates to a double-layer furnace liner for the preheating section of a stainless steel annealing furnace. Background Art

[0002] The demand in the stainless steel market shows a rapid growth trend, especially the demand for high-quality stainless steel products is increasing. After passing through a bright annealing furnace, the stainless steel strip can not only obtain a satisfactory metallographic structure by eliminating work hardening, but also obtain a non-oxidized bright surface, so it is highly favored by the market.

[0003] A bright annealing furnace usually mainly consists of components such as a furnace shell, refractories, a furnace liner, heating components, and gas charging components. Among them, the furnace liner plays a role in ensuring that the atmosphere inside the furnace liner is not affected by the outside world and preventing the strip steel from oxidizing when heated at high temperature. Therefore, the structure of the furnace liner has a very great influence on the performance and heating effect of the final product.

[0004] In the production process, in order to save fuel, no burners are arranged in the preheating section of the bright annealing furnace, and the furnace liner is directly heated by high-temperature flue gas. At present, the furnace liner in the preheating section usually adopts a single-layer structure, with poor heat exchange effect, unable to make good use of the waste heat of the flue gas, resulting in high energy consumption.

[0005] Therefore, a new furnace liner structure is needed to make full use of the waste heat of high-temperature flue gas to achieve the purpose of energy conservation and consumption reduction. Content of the Utility Model

[0006] The technical problem to be solved by the utility model is to provide a double-layer furnace liner for the preheating section of a stainless steel annealing furnace in view of the above problems. The flue gas flows through the interlayer of the furnace liner and flows out from the flue gas outlet. The flow direction of the flue gas is opposite to the movement direction of the strip steel, forming countercurrent heat exchange to heat the entire furnace liner.

[0007] The technical solution adopted by the utility model to solve the above technical problems is: a double-layer furnace liner for the preheating section of a stainless steel annealing furnace, characterized in that it includes an outer furnace liner and an inner furnace liner sleeved inside and outside, forming an annular interlayer cavity for flue gas circulation. A plurality of upper flow channel plates are evenly spaced along the axial direction at the upper part of the annular interlayer cavity, and a plurality of lower flow channel plates are inclined and arranged at intervals at the lower part of the annular cavity. The two ends of the lower flow channel plates are respectively connected to the left and right diagonal corners of two of the upper flow channel plates, forming a spiral flow channel around the inner furnace liner. The upper flow channel plates and the lower flow channel plates are both connected to the inner wall of the outer furnace liner and the outer wall of the inner furnace liner.

[0008] According to the above scheme, both the outer furnace liner and the inner furnace liner have a structure with an arched top and a flat bottom.

[0009] According to the above solution, the spiral flow channel is divided into a front section area and a rear section area. A transformation space is formed between the tail of the front section area and the head of the rear section area. The last upper flow channel plate of the front section area is the first upper flow channel plate of the rear section area. The front section area is a parallel double spiral flow channel, and the rear section area is a single spiral flow channel.

[0010] According to the above solution, the double spiral flow channel is formed by multiple lower flow channel plates arranged in parallel and the corresponding upper flow channel plates. The two ends of the first lower flow channel plate are respectively corresponding to the middle position of the inlet of the front section area and one end of the second lower flow channel plate. The two ends of the middle multiple lower flow channel plates are respectively corresponding to the left and right diagonal positions of two lower flow channel plates with one lower flow channel plate spaced in the middle in turn. The two ends of the last lower flow channel plate are respectively corresponding to the other end of the last lower flow channel plate of the front section area and the middle position of the tail.

[0011] According to the above solution, the single spiral flow channel is formed by multiple lower flow channel plates arranged in parallel and the corresponding upper flow channel plates. The two ends of each lower flow channel plate are respectively corresponding to the left and right diagonal positions of two adjacent upper flow channel plates.

[0012] According to the above solution, heat exchange fins are arranged in parallel at intervals between two adjacent lower flow channel plates.

[0013] According to the above solution, a flue gas outlet pipe communicating with the annular sandwich cavity is provided on the top surface of the tail of the outer furnace liner.

[0014] According to the above solution, the height of the heat exchange fins is not greater than 30 mm.

[0015] According to the above solution, the width of the inner furnace liner is greater than the sum of the maximum width of the product strip steel and the maximum deviation amount.

[0016] According to the above solution, the vertical distance between the highest point of the top of the inner furnace liner and the product strip steel is 180 mm to 220 mm, and the vertical distance between the bottom of the inner furnace liner and the product strip steel is 15 mm to 30 mm.

[0017] The beneficial effects of the present utility model are as follows: A double-layer furnace liner for the preheating section of a stainless steel annealing furnace is provided, forming an interlayer cavity. Flue gas flows through the interlayer cavity and exits from the flue gas outlet. The flow direction of the flue gas is opposite to the movement direction of the strip steel, forming countercurrent heat exchange. A number of upper flow channel plates and lower flow channel plates are arranged in the interlayer to form spiral flow channels, enabling the flue gas to rotate around the furnace liner, increasing the flow distance, and improving the heat exchange efficiency. Through the arrangement of the lower flow channel plates, double spiral flow channels are formed on the flue gas inlet side, reducing the flow resistance on the inlet side. A number of heat exchange fins with a height not exceeding 30 mm are added in the lower flow channel plates to further strengthen heat exchange and improve the heat exchange effect. The top of the furnace liner is arched, increasing the radiant heat transfer to the product strip steel and further enhancing the heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a front view of an embodiment of the present utility model;

[0019] Figure 2 is an axonometric view of an embodiment of the present utility model with the outer furnace liner hidden;

[0020] Figure 3 is an axonometric view of another perspective of an embodiment of the present utility model with the outer furnace liner hidden. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] To better understand the present utility model, the present utility model will be further described below in conjunction with the drawings and embodiments.

[0022] It should be noted that in the description of the present utility model, the orientation or positional relationships indicated by the terms "transverse", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0023] Such as Figure 1As shown in the figure, a double-layer furnace liner for the preheating section of a stainless steel annealing furnace includes an outer furnace liner 1 and an inner furnace liner 2 which are sleeved inside and outside each other, forming an annular sandwich cavity 3 for flue gas circulation. Along the axial direction, multiple upper flow channel plates 4 are evenly spaced at the upper part of the annular sandwich cavity, and multiple lower flow channel plates 5 which are inclined are spaced at the lower part of the annular cavity. The two ends of the lower flow channel plates are respectively connected corresponding to the left and right diagonal corners of two upper flow channel plates, forming a spiral flow channel around the inner furnace liner. Both the upper flow channel plates and the lower flow channel plates are connected to the inner wall of the outer furnace liner and the outer wall of the inner furnace liner. A flue gas outlet pipe 6 communicating with the annular sandwich cavity is provided on the top surface at the tail of the outer furnace liner. The flue gas flows through the annular sandwich cavity and flows out from the flue gas outlet pipe. The flowing direction of the flue gas is opposite to the moving direction of the strip steel, forming countercurrent heat exchange to heat the entire furnace liner.

[0024] At the same time, the upper flow channel plates and the lower flow channel plates also play the role of stiffening ribs, improving the structural stability of the double-layer furnace liner.

[0025] Both the outer furnace liner and the inner furnace liner have a structure with an arched top surface and a flat bottom surface. The upper part is designed to be arched, increasing the upper heat transfer area and the radiant heat transfer to the product strip steel.

[0026] The spiral flow channel is divided into a front section area and a rear section area. A transformation space 7 is formed between the tail of the front section area and the head of the rear section area. The last upper flow channel plate in the front section area is the first upper flow channel plate in the rear section area. The front section area is a parallel double-spiral flow channel, and the rear section area is a single-spiral flow channel. The flue gas flowing in the double-spiral flow channel converges in the transformation space and enters the single-spiral flow channel.

[0027] The double-spiral flow channel is formed by multiple lower flow channel plates arranged in parallel and the corresponding upper flow channel plates. The two ends of the first lower flow channel plate are respectively corresponding to the middle position of the inlet in the front section area and one end of the second lower flow channel plate. The two ends of the multiple middle lower flow channel plates are sequentially respectively corresponding to the left and right diagonal corners of two lower flow channel plates with one lower flow channel plate spaced in the middle. The two ends of the last lower flow channel plate are respectively corresponding to the other end of the last lower flow channel plate in the front section area and the middle position of the tail.

[0028] The setting of the double-spiral flow channel on the inlet side forms a double flow channel near the flue gas inlet side, reducing the flow resistance.

[0029] The single-spiral flow channel is formed by multiple lower flow channel plates arranged in parallel and the corresponding upper flow channel plates. The two ends of each lower flow channel plate are respectively corresponding to the left and right diagonal corners of two adjacent upper flow channel plates.

[0030] Heat exchange fins 8 with a height not exceeding 30 mm are arranged in parallel and spaced between two adjacent lower flow channel plates, further strengthening the heat exchange effect.

[0031] The width of the inner furnace lining of the double-layer furnace lining is determined according to the maximum width of the strip steel for the produced product and the maximum deviation amount, ensuring that the edge of the strip steel does not rub against or collide with the inner wall of the furnace lining and minimizing the width as much as possible. In the height direction, it is determined according to the sag degree of the strip steel, ensuring that the lowest point of the strip steel is between 15 mm and 30 mm away from the bottom of the inner furnace lining. The inner top of the furnace lining above the strip passing line is made into an arched structure, and the highest point is generally between 180 mm and 220 mm away from the strip passing line, which is convenient for threading the strip steel and does not increase the volume of the furnace lining too much. In short, on the premise of meeting the process requirements and product quality, reducing the internal volume of the furnace lining is beneficial to strengthening heat transfer and reducing costs at the same time.

[0032] The above content is only used to help understand the method and core idea of the present utility model and is not intended to limit the present utility model; at the same time, those of ordinary skill in the art can also understand that, based on the idea of the present utility model, there may be changes in the specific implementation manner and application scope. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present utility model are all included in the protection scope of the present utility model.

Claims

1. A double-layer furnace for the preheating section of a stainless steel annealing furnace, characterized in that: It comprises an outer furnace liner and an inner furnace liner which are arranged inside and outside, forming an annular sandwich cavity for smoke circulation, a plurality of upper flow channel plates are evenly spaced along the axial direction on the upper part of the annular sandwich cavity, a plurality of lower flow channel plates are obliquely spaced on the lower part of the annular cavity, two ends of the lower flow channel plates are respectively connected to the left and right diagonal corners of the two upper flow channel plates to form a spiral flow channel arranged around the inner furnace liner, and the upper flow channel plates and the lower flow channel plates are both connected to the inner wall of the outer furnace liner and the outer wall of the inner furnace liner.

2. The double-layer furnace for the preheating section of a stainless steel annealing furnace according to claim 1, characterized in that: The outer furnace liner and the inner furnace liner are both structures with an arched top surface and a flat bottom surface.

3. The double-layer furnace for the preheating section of a stainless steel annealing furnace according to claim 2, characterized in that: The spiral flow channel is divided into a front section area and a rear section area, a transformation space is formed between the tail of the front section area and the head of the rear section area, the last upper flow channel plate of the front section area is the first upper flow channel plate of the rear section area, the front section area is a parallel double spiral flow channel, and the rear section area is a single spiral flow channel.

4. The double-layer furnace for the preheating section of a stainless steel annealing furnace according to claim 3, characterized in that: The double helix flow channel is formed by a plurality of lower flow channel plates arranged in parallel and the corresponding upper flow channel plates. The two ends of the first lower flow channel plate are respectively arranged corresponding to the middle position of the inlet of the front section area and one end of the second lower flow channel plate. The two ends of the middle multiple lower flow channel plates are respectively arranged corresponding to the left and right diagonal positions of the two lower flow channel plates separated by a lower flow channel plate in between. The two ends of the last lower flow channel plate are respectively arranged corresponding to the other end of the last lower flow channel plate in the front section area and the middle position of the tail.

5. The double-layer furnace for the preheating section of a stainless steel annealing furnace according to claim 4, characterized in that: The single spiral flow channel is formed by a plurality of lower flow channel plates arranged in parallel and the corresponding upper flow channel plates, and the two ends of each lower flow channel plate are respectively arranged corresponding to the left and right diagonal positions of two adjacent upper flow channel plates.

6. The double-layer furnace for the preheating section of a stainless steel annealing furnace according to claim 5, characterized in that: Heat exchange fins are arranged in parallel and at intervals between two adjacent lower flow channel plates.

7. The double-layer furnace for the preheating section of a stainless steel annealing furnace according to claim 6, characterized in that: A smoke outlet pipe communicating with the annular sandwich cavity is arranged on the top surface of the tail portion of the outer furnace.

8. The double-layer furnace for the preheating section of a stainless steel annealing furnace according to claim 6, characterized in that: The height of the heat exchange fins is no more than 30 mm.

9. The double-layer furnace for the preheating section of a stainless steel annealing furnace according to claim 8, characterized in that: The width of the inner furnace is greater than the sum of the maximum width and the maximum deviation of the product strip.

10. The double-layer furnace for the preheating section of a stainless steel annealing furnace according to claim 9, characterized in that: The vertical distance between the highest point on the top of the inner furnace and the product strip steel is 180mm-220mm, and the vertical distance between the bottom of the inner furnace and the product strip steel is 15mm-30mm.

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