A circulating heating oven for pipe processing

Abstract

The utility model provides a kind of circulation formula heating oven for pipe processing, it is related to pipe heating technical field, including oven main body, transmission hole is opened in oven main body two ends, each transmission hole outside is fixed annular mounting box, annular mounting box is formed annular air conveying cavity and is opened several air holes towards oven interior, it is connected between two annular mounting boxes by outside delivery pipeline, and circulation fan is set on pipeline.The utility model is driven by circulation fan, and hot air in oven forms the forced circulation flow from discharge end to feeding end, effectively solve the temperature uneven problem existing in traditional oven, make pipe circumferential and axial heating uniform, avoid local overheating, significantly improve the heating quality of PP pipe before flaring and bidirectional stretching processing, simultaneously realize waste heat recovery, reduce energy consumption.

Description

Technical Field

[0001] This utility model mainly relates to the field of pipe heating technology, specifically to a circulating heating oven for pipe processing. Background Technology

[0002] In advanced processing of polypropylene (PP) pipes, biaxial stretching (simultaneous axial and radial stretching) technology can significantly improve the ring stiffness, impact toughness, and dimensional stability of the pipes, producing high-performance modified pipes. This process requires simultaneous radial flaring and axial stretching of the pipe blank, which places extremely stringent requirements on the heating process: the area to be deformed in the pipe must achieve a highly uniform plastic state in both the circumferential and axial directions. Temperature differences in any area will lead to uneven orientation of the material's molecular chains, resulting in uneven wall thickness, stress concentration, and even tearing.

[0003] Currently, tunnel-type heating ovens are commonly used in this field to preheat pipes. These ovens typically have several electric heating tubes or hot air nozzles fixedly installed on the top, bottom, or sides of their inner walls as heat sources. The pipes are fed into the oven through the inlet and heated by the fixed heat sources as they pass through the oven.

[0004] However, this traditional heating method is difficult to meet the uniformity requirements of biaxial stretching when used in the process. This is mainly because the fixed heat source leads to uneven heating of the tubes in the oven, resulting in temperature gradients at different circumferential angles and axial positions. This non-uniformity may be tolerable for ordinary flaring, but it is fatal for the precision biaxial stretching process. It directly causes inconsistent flow resistance during stretching deformation, premature thinning or overstretching in some areas, seriously affecting the product quality and performance consistency of the biaxially stretched tubes.

[0005] Furthermore, the heat distribution within the oven is uneven, with a low temperature at the inlet and heat accumulation at the outlet. To ensure the precise process temperature required for biaxial stretching is reached in the middle section of the oven, the overall heating power must be increased. This not only wastes energy but also increases the risk of overheating in the pipe at the outlet. This unstable thermal environment makes it difficult to precisely control process parameters, affecting the stability of continuous production and the yield rate. Utility Model Content

[0006] 1. The technical problem to be solved by the utility model: This utility model provides a circulating heating oven for pipe processing to solve the technical problems existing in the background art.

[0007] 2. Technical Solution: To achieve the above objectives, the technical solution provided by this utility model is as follows: a circulating heating oven for pipe processing, comprising an oven body, wherein transmission holes for passing through pipes are respectively opened at both ends of the oven body along its length direction; Each of the aforementioned transmission holes is fixedly provided with an annular mounting box on its outer side. An annular air supply cavity is formed inside the annular mounting box, and the annular air supply cavity has several ventilation holes on the side facing the interior of the oven body. An external conveying pipe connects the annular mounting boxes at both ends of the oven body. A circulating fan is installed on this external conveying pipe to drive airflow in a forced circulation from the discharge end to the inlet end of the oven body. The circulating fan starts working after the oven is started or after a period of operation. It draws hot air from the air delivery chamber of the annular mounting box at the discharge end and forces it to the annular mounting box at the inlet end through the external conveying pipe. The hot air is then evenly sprayed into the oven through multiple ventilation holes in the annular air delivery chamber at the inlet end. As this airflow flows towards the discharge end, it exchanges heat with the pipes, heating them. Finally, the airflow is collected again by the annular mounting box at the discharge end and enters the next cycle. This process repeats continuously, forming a stable and clearly defined circulating drying air duct within the oven.

[0008] This forced circulation mechanism breaks through the limitations of traditional ovens that rely on natural convection or localized agitation for uneven temperature distribution. It allows hot air to penetrate the entire working area of ​​the oven, significantly improving the uniformity of circumferential and axial heating of the pipes and effectively preventing localized overheating. This is particularly beneficial for subsequent flaring and biaxial stretching processes of PP pipes, ensuring product quality. Simultaneously, recovering the higher-temperature outlet hot air for preheating the inlet pipes reduces heat loss and achieves energy-saving operation.

[0009] It should be noted that the inventive point of this utility model lies in the improvement of the existing oven structure, particularly the hot air circulation system and related support mechanisms. Therefore, the main body of the oven involved in this application, its box structure, internal heating elements such as electric heating tubes and infrared heaters, temperature control devices for maintaining the set process temperature, and temperature protection devices for over-temperature protection, such as fuses and mechanical temperature control switches, all adopt the conventional and mature configurations of tubular heating ovens described in this technical field. Those skilled in the art can perform conventional selection and settings according to specific production needs, such as heating power and temperature control accuracy. The scope of protection of this utility model does not involve improvements to these prior art components themselves.

[0010] Furthermore, the external conveying pipeline is an insulated pipeline.

[0011] Furthermore, an annular mounting box is fixedly connected to an annular mounting plate at one end near the oven body; the annular mounting plate has multiple mounting holes, and the mounting holes are fixedly connected to the oven body around the transmission hole by fasteners passing through the mounting holes; the inner ring area of ​​the annular mounting plate has multiple ventilation holes arranged in a ring.

[0012] Furthermore, the side wall of the annular mounting box is provided with a connection interface, which is connected to the annular air supply cavity; the end of the external conveying pipe is sleeved on the connection interface and locked and fixed by a pipe clamp.

[0013] Furthermore, the oven body is configured to be at least one; when there are multiple oven bodies, the multiple oven bodies are connected in series along the pipe conveying direction to jointly form an extended circulating heating oven.

[0014] Furthermore, a support frame is fixedly connected to the bottom of the oven body; a detachable I-shaped mounting block is provided at the middle of both ends of the support frame along its length direction, and a connecting block is fixedly provided at the end of the I-shaped mounting block away from the support frame, and a vertical connecting hole is opened in the center of the connecting block; the connecting hole can be detachably connected to the lifting support mechanism.

[0015] Furthermore, the lifting support mechanism includes a lifting column, which has a vertical guide groove on the side facing the connecting block, and the guide groove and the connecting hole are in sliding fit; a positioning bolt is also provided on the connecting block, and the end of the positioning bolt is operably pressed against the guide groove to lock the vertical position of the lifting column; a concave support block is connected to the top of the lifting column, and a concave support roller for directly supporting the support material is rotatably connected to the concave support block through a rotating shaft.

[0016] 3. Beneficial effects: Compared with the prior art, the technical solution provided by this utility model has the following advantages: This utility model is reasonably designed. Through a forced circulation system consisting of a ring-shaped mounting box, an external conveying pipe, and a circulating fan, hot air from the discharge end is recovered to the feed end, forming a stable and uniform circulating airflow in the oven. This fundamentally solves the problem of uneven heating of the pipe in the circumferential and axial directions, significantly improves the heating quality, and effectively recovers waste heat, reducing energy consumption.

[0017] The modular design of the ring-shaped mounting box and the series-connectable oven structure give the equipment high configuration flexibility, enabling it to quickly adapt to the needs of different production lines. Combined with an adjustable lifting support mechanism, it ensures the straightness and stability of various pipe diameters during the heating process. The entire system has a reasonable structure and is easy to assemble and disassemble, improving process quality while also enhancing the equipment's applicability and maintainability. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the structure of this utility model from another angle; Figure 3 This is a schematic diagram of the annular mounting box of this utility model when it is removed; Figure 4 This is a schematic diagram of the annular mounting box structure of this utility model; Figure 5 This is a cross-sectional view of the present invention during air circulation; Figure 6 This is a schematic diagram of the combined structure of this utility model.

[0019] Figure label: 1. Oven body; 2. Transfer hole; 3. Annular mounting box; 4. Annular air supply cavity; 5. Ventilation hole; 6. External conveying pipe; 7. Circulating fan; 11. Support frame; 12. I-shaped mounting block; 13. Connecting block; 14. Connecting hole; 15. Lifting support mechanism; 31. Annular mounting plate; 32. Connecting interface; 151. Lifting column; 152. Guide groove; 153. Positioning bolt; 154. Concave support block; 155. Concave support roller. Detailed Implementation

[0020] To facilitate understanding of this utility model, a more comprehensive description of the utility model will be given below with reference to the accompanying drawings, which show several embodiments of the utility model. However, the utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the utility model will be more thorough and complete.

[0021] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "page", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this utility model, unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," "fixed," "provided with," and "located in" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0024] It should be noted that the structures not described in this utility model do not involve the design points and improvement directions of this utility model, and can all adopt existing technologies known to those skilled in the art.

[0025] The specific implementation of this utility model will be described in detail below with reference to specific embodiments.

[0026] See attached document Figure 1-6 A circulating heating oven for pipe processing includes an oven body 1, wherein transmission holes 2 for passing pipes are respectively opened at both ends of the oven body 1 along its length direction; Each of the transmission holes 2 is fixedly provided with an annular mounting box 3 on its outer side. An annular air supply cavity 4 is formed inside the annular mounting box 3, and several ventilation holes 5 are opened on the side of the annular air supply cavity 4 facing the inside of the oven body 1. An external conveying pipe 6 connects the annular mounting boxes 3 at both ends of the oven body 1. A circulating fan 7 is installed on the external conveying pipe 6 to drive airflow in a forced circulation from the discharge end to the inlet end of the oven body 1. In this embodiment, the circulating fan 7 starts working after the oven is started or after operating for a period of time. It draws hot air from the air delivery chamber of the annular mounting box 3 at the discharge end and forces it to the annular mounting box 3 at the inlet end through the external conveying pipe 6. The hot air is then evenly sprayed into the oven from multiple ventilation holes 5 of the annular air delivery chamber 4 at the inlet end. As this airflow flows towards the discharge end, it exchanges heat with the pipe material, heating it. Finally, the airflow is collected again by the annular mounting box 3 at the discharge end and enters the next cycle. This process repeats continuously, forming a stable and clearly defined circulating drying air duct within the oven.

[0027] This forced circulation mechanism breaks through the limitations of traditional ovens that rely on natural convection or localized agitation for uneven temperature distribution. It allows hot air to penetrate the entire working area of ​​the oven, significantly improving the uniformity of circumferential and axial heating of the pipes and effectively preventing localized overheating. This is particularly beneficial for subsequent flaring and biaxial stretching processes of PP pipes, ensuring product quality. Simultaneously, recovering the higher-temperature outlet hot air for preheating the inlet pipes reduces heat loss and achieves energy-saving operation.

[0028] It should be noted that the inventive point of this utility model lies in the improvement of the existing oven structure, particularly the hot air circulation system and related support mechanisms. Therefore, the oven body 1 involved in this application, its box structure, internal heating elements such as electric heating tubes and infrared heaters, temperature control devices for maintaining the set process temperature, and temperature protection devices for over-temperature protection, such as fuses and mechanical temperature control switches, all adopt conventional and mature configurations of tubular heating ovens described in this technical field. Those skilled in the art can make conventional selections and settings according to specific production needs, such as heating power and temperature control accuracy. The scope of protection of this utility model does not involve improvements to these prior art components themselves.

[0029] The external conveying pipe 6 is an insulated pipe. In this embodiment, the insulated pipe can be made of common industrial insulation materials such as rock wool insulation pipe, glass wool insulation pipe, or polyurethane foam insulation pipe. It is connected to the air supply cavity of the annular mounting box 3, thereby forming a closed airflow circulation channel.

[0030] Please refer to this carefully. Figure 3 The annular mounting box 3 is fixedly connected to an annular mounting plate 31 at one end near the oven body 1. The annular mounting plate 31 has multiple mounting holes, which are fixedly connected to the oven body 1 around the transmission hole 2 by fasteners passing through them. The inner ring area of ​​the annular mounting plate 31 has multiple ventilation holes 5 arranged in a ring. In this embodiment, a portion of the circulating airflow is evenly sprayed from the ventilation holes 5 of the annular mounting plate 31 at the feed end to preheat the newly entered pipe; another portion of the airflow is drawn in from the ventilation holes 5 of the annular mounting plate 31 at the discharge end and enters the circulation system. This structural design allows the annular mounting box 3 and its internal air delivery chamber to be installed and disassembled as a single module, greatly facilitating equipment maintenance and cleaning. More importantly, the ventilation holes 5 of the annular array can ensure that the airflow is evenly delivered and drawn out in the circumferential direction of the pipe. Together with the circumferential air outlet of the annular mounting box 3, they form a multi-dimensional uniform air supply system, which fundamentally avoids the problem of local overheating of the pipe caused by uneven airflow distribution and provides a crucial uniform thermal environment for the biaxial stretching process.

[0031] Please refer to this carefully. Figure 1 and Figure 4 The annular mounting box 3 has a connection interface 32 on its side wall, which is connected to the annular air supply cavity 4. The end of the external conveying pipe 6 is sleeved on the connection interface 32 and locked in place by a pipe clamp. In this embodiment, the sleeve and pipe clamp locking method constitutes a detachable fastening connection, which is not only easy to install, but also ensures the airtightness of the connection interface 32, effectively preventing hot air leakage at key connection points and ensuring the overall efficiency of the circulating air duct.

[0032] The oven body 1 is configured as at least one; when there are multiple oven bodies 1, the multiple oven bodies 1 are connected in series along the pipe conveying direction to jointly form an extended circulating heating oven. In this embodiment, please refer to... Figure 6 The oven body 1 can be used independently, or multiple oven bodies 1 with the same structure can be connected in series along the pipe conveying direction to form an extended circulating heating oven, according to the specific requirements of the heating zone length in the actual production process.

[0033] Its working principle is that each independent oven main body module 1 is equipped with the aforementioned circulating air duct system. When multiple modules are connected in series, the two annular mounting boxes 3 located at the feed end and discharge end of the entire equipment, together with the external conveying pipe 6 and the circulating fan 7, constitute a centralized hot air circulation system that runs through the entire extended oven. The airflow is drawn from the final discharge end, transported through the insulated pipe to the initial feed end, and forms a stable, continuous, and uniform temperature field inside the extended oven.

[0034] Please refer to this carefully. Figure 4 The bottom of the oven body 1 is fixedly connected to a support frame 11; a detachable I-shaped mounting block 12 is provided at the middle of both ends of the support frame 11 along its length direction, and a connecting block 13 is fixedly provided at the end of the I-shaped mounting block 12 away from the support frame 11. A vertical connecting hole 14 is opened in the center of the connecting block 13; the connecting hole 14 is detachably connected to a lifting support mechanism 15. In this embodiment, according to the specifications of the pipe to be processed, the absolute height of the support component is adjusted by the lifting support mechanism 15 so that it can accurately support the pipe and ensure that the axis of the pipe is consistent with the center line of the transmission hole 2 when the pipe passes through the oven. The stable I-shaped mounting block 12 and the detachable connection method not only ensure the reliability of the support, but also provide convenience for equipment maintenance.

[0035] Please refer to this carefully. Figure 4The lifting support mechanism 15 includes a lifting column 151. The lifting column 151 has a vertical guide groove 152 on the side facing the connecting block 13. The guide groove 152 and the connecting hole 14 form a sliding fit. The connecting block 13 is also provided with a positioning bolt 153. The end of the positioning bolt 153 is operably pressed against the guide groove 152 to lock the vertical position of the lifting column 151. The top of the lifting column 151 is connected to a concave support block 154. A concave support roller 155 for directly supporting the pipe is rotatably connected to the concave support block 154 through a rotating shaft. In this embodiment, when it is necessary to adjust the support height, the positioning bolt 153 is loosened first. At this time, the extension length of the lifting column 151 can be adjusted manually or by the drive device, thereby driving the top concave support roller 155 to rise and fall synchronously. After the support roller lifts the pipe to the required height, usually aligning the pipe axis with the center of the transmission hole 2, the positioning bolt 153 is tightened again to complete the fixation. When the pipe is conveyed through the oven, the outer wall of the pipe comes into contact with the concave support roller 155, which drives the support roller to rotate freely around its axis.

[0036] The above-described embodiments are merely illustrative of certain implementations of this utility model, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these modifications and improvements all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A circulating heating oven for pipe processing, comprising an oven body (1), characterized in that: The oven body (1) has transmission holes (2) for inserting pipes at both ends along its length. Each of the transmission holes (2) is fixed with an annular mounting box (3) on its outer side. An annular air supply cavity (4) is formed inside the annular mounting box (3), and the annular air supply cavity (4) has several ventilation holes (5) on the side facing the interior of the oven body (1). An external conveying pipe (6) is connected between the annular mounting boxes (3) at both ends of the oven body (1). A circulating fan (7) is installed on the external conveying pipe (6) to drive the airflow to circulate from the discharge end to the feed end of the oven body (1).

2. The circulating heating oven for pipe processing according to claim 1, characterized in that: The external conveying pipeline (6) is an insulated pipeline.

3. The circulating heating oven for pipe processing according to claim 1, characterized in that: The annular mounting box (3) is fixedly connected to an annular mounting plate (31) at one end near the oven body (1); the annular mounting plate (31) has multiple mounting holes, and the mounting holes are fixedly connected to the oven body (1) around the transmission hole (2) by fasteners passing through the mounting holes; the inner ring area of ​​the annular mounting plate (31) has multiple ventilation holes (5) arranged in a ring.

4. The circulating heating oven for pipe processing according to claim 1, characterized in that: The annular mounting box (3) has a connection interface (32) on its side wall, which is connected to the annular air supply cavity (4); the end of the external conveying pipe (6) is fitted onto the connection interface (32) and locked and fixed by a pipe clamp.

5. A circulating heating oven for pipe processing according to claim 1, characterized in that: The oven body (1) is set to at least one; when there are multiple oven bodies (1), the multiple oven bodies (1) are connected in series along the pipe conveying direction to form an extended circulating heating oven.

6. A circulating heating oven for pipe processing according to claim 1, characterized in that: The bottom of the oven body (1) is fixedly connected to a support frame (11); the support frame (11) is provided with a detachable I-shaped mounting block (12) at the middle of both ends along its length direction, and a connecting block (13) is fixedly provided at the end of the I-shaped mounting block (12) away from the support frame (11), and a vertical connecting hole (14) is opened in the center of the connecting block (13); the connecting hole (14) is detachably connected to the lifting support mechanism (15).

7. A circulating heating oven for pipe processing according to claim 6, characterized in that: The lifting support mechanism (15) includes a lifting column (151), on which a vertical guide groove (152) is provided on the side facing the connecting block (13), and the guide groove (152) and the connecting hole (14) form a sliding fit; a positioning bolt (153) is also provided on the connecting block (13), and the end of the positioning bolt (153) is operablely pressed against the guide groove (152) to lock the vertical position of the lifting column (151); a concave support block (154) is connected to the top of the lifting column (151), and a concave support roller (155) for directly supporting the support material is rotatably connected to the concave support block (154) through a rotating shaft.

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