A plate heat exchanger capable of adjusting the angle of heat exchange plates according to air outlet temperature

Abstract

This invention provides a plate heat exchanger with adjustable heat exchange plate angles based on outlet air temperature, relating to the field of plate heat exchangers. It includes a housing, with an exhaust gas inlet pipe and an exhaust gas outlet pipe fixedly connected to the left and right sides of the housing, respectively, and a fresh air fan and a fresh air outlet pipe fixedly connected to the front and rear sides of the housing, respectively. A heat exchange plate mechanism is fixedly connected inside the housing. The heat exchange plate mechanism includes a base, a top seat, a supporting reinforcing rod, a first heat exchange plate, and a second heat exchange plate. The base and top seat are fixedly connected via the supporting reinforcing rod. This plate heat exchanger with adjustable heat exchange plate angles addresses the large temperature fluctuations in exhaust gas from stenters by using a temperature sensor to detect the temperature difference between the exhaust gas inlet and outlet. When the temperature difference is too small, the angle of the guide plate is automatically reduced, causing the exhaust gas to flow in a U-shaped channel, extending the heat exchange time and increasing the fresh air outlet temperature; conversely, the angle of the guide plate is increased when the temperature difference is too large, achieving adaptive control.

Description

Technical Field

[0001] This invention relates to the field of plate heat exchanger technology, specifically to a plate heat exchanger whose heat exchange plate angle can be adjusted according to the outlet air temperature. Background Technology

[0002] Stenter machines are key equipment in the textile printing and dyeing industry, typically operating at temperatures between 120℃ and 180℃. Their exhaust gases contain a large amount of heat, water vapor, oil mist, and fiber dust. Direct emission of these gases wastes energy and pollutes the environment; therefore, plate heat exchangers are often used to recover waste heat from the exhaust gases and preheat the fresh air entering the stenter, thus reducing energy consumption.

[0003] However, traditional plate heat exchangers cannot adjust the heat exchange area. When the temperature difference between the exhaust gas inlet and outlet is too small, it indicates that the heat exchange capacity is excessive, and it is necessary to reduce the exhaust gas flow rate or change the airflow path to extend the heat exchange time. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a plate heat exchanger whose heat exchange plate angle can be adjusted according to the outlet air temperature. An independently controllable air guide plate is set at the opening of the heat exchange plate on the exhaust gas side. By detecting the temperature difference between the inlet and outlet air through a temperature sensor, the angle of the air guide plate is automatically adjusted to change the effective cross-sectional area and airflow path of the exhaust gas channel, thereby controlling the heat exchange intensity, adapting to the fluctuation of the exhaust gas conditions of the stenter, and ensuring the stability of the fresh air outlet temperature.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a plate heat exchanger with adjustable heat exchange plate angles according to outlet air temperature, comprising a shell, with an exhaust gas inlet pipe and an exhaust gas outlet pipe fixedly connected to the left and right sides of the shell, respectively, and a fresh air fan and a fresh air outlet pipe fixedly connected to the front and rear sides of the shell, respectively; a heat exchange plate mechanism is fixedly connected inside the shell; the heat exchange plate mechanism includes a base, a top seat, a supporting reinforcing rod, a first heat exchange plate, and a second heat exchange plate; the base and the top seat are fixedly connected by the supporting reinforcing rod; the first heat exchange plate and the second heat exchange plate are alternately arranged between the base and the top seat, and both are U-shaped groove structures; a first heat exchange air duct is formed inside the first heat exchange plate, with its two ends connected to the exhaust gas inlet pipe and the exhaust gas outlet pipe, respectively; a second heat exchange air duct is formed inside the second heat exchange plate, with its two ends connected to the fresh air fan and the fresh air outlet pipe, respectively.

[0006] Furthermore, the height of the first heat exchange plate is more than twice the height of the second heat exchange plate.

[0007] Furthermore, a first air guide plate and a second air guide plate are rotatably connected to both sides of the opening of each of the first heat exchange plates; a first synchronization rod in the vertical direction is connected to the outer side of the plurality of first air guide plates, and each first air guide plate is rotatably connected to the first synchronization rod; a second synchronization rod in the vertical direction is connected to the outer side of the plurality of second air guide plates, and each second air guide plate is rotatably connected to the second synchronization rod; two driving mechanisms are provided in the top seat, which are respectively connected to the first air guide plate and the second air guide plate in a transmission connection.

[0008] Furthermore, the drive mechanism includes a motor, a rotating shaft, a take-up reel, a cable, and a guide wheel; the motor is fixed inside the top seat, and its output end is connected to the rotating shaft for transmission; two take-up reels are fixedly connected to the rotating shaft, and the guide wheel is mounted on the top seat; one end of the cable is fixedly connected to the take-up reel, and the other end passes around the guide wheel and is fixedly connected to the outer end of the corresponding air guide plate.

[0009] Furthermore, a first temperature sensor and a second temperature sensor are fixedly connected to the exhaust gas inlet pipe and the exhaust gas outlet pipe, respectively; when the temperature difference between the first temperature sensor and the second temperature sensor is configured to be less than 30°, the driving mechanism drives the first air guide plate to rotate to a position of 25° to 35° with the airflow direction.

[0010] Furthermore, a third temperature sensor and a fourth temperature sensor are fixedly connected to the fresh air fan and the fresh air outlet duct, respectively; when the temperature difference between the third temperature sensor and the fourth temperature sensor is configured to be less than 30°, the drive mechanism drives the second air guide plate to rotate to a position of 25° to 35° with the airflow direction.

[0011] Furthermore, the lengths of the first air guide plate and the second air guide plate are equal.

[0012] Furthermore, elastic reset members are provided on both the left and right sides of the base. One end of the elastic reset member is fixedly connected to the base, and the other end is fixedly connected to the corresponding first or second air guide plate, which is used to suppress the shaking of the air guide plate when the airflow fluctuates.

[0013] Furthermore, there are multiple supporting and reinforcing rods, and the first heat exchange plate and the second heat exchange plate are each provided with mounting holes corresponding to the supporting and reinforcing rods. The first heat exchange plate and the second heat exchange plate pass through the supporting and reinforcing rods.

[0014] Furthermore, the first and second air guide plates have the following four working angle states: First state: Both the first and second air guide plates are rotated to the fully open position at 0° with the airflow direction. At this time, the cross-sectional area of ​​the exhaust gas passage is the largest and the flow rate is the largest, but the direct heat exchange time of the exhaust gas is the shortest and the heat exchange efficiency is the lowest. Second state: The first guide vane is rotated to an adjustment position of 25° to 35° with the airflow direction, and the second guide vane remains fully open. At this time, one side of the exhaust gas passage is blocked, forming an asymmetrical airflow. Third state: The first air guide plate remains fully open, and the second air guide plate is rotated to an adjustment position of 25° to 35° with the airflow direction. At this time, the other side of the exhaust gas passage is blocked, forming a reverse asymmetric airflow. Fourth state: Both the first and second air guide plates are rotated to an adjustment position of 25° to 35° with the airflow direction. At this time, the exhaust gas is forced to flow in a tortuous manner along the U-shaped heat exchange channel, with the longest heat exchange path, the longest residence time, and the most complete heat exchange.

[0015] This invention provides a plate heat exchanger with adjustable plate angle according to outlet air temperature, which has the following advantages: 1. This plate heat exchanger, which can adjust the angle of the heat exchange plates according to the outlet air temperature, is designed to address the large temperature fluctuations in the exhaust gas from the stenter. It uses a temperature sensor to detect the temperature difference between the exhaust gas inlet and outlet. When the temperature difference is too small, it automatically adjusts the angle of the air guide plate to make the exhaust gas flow in a tortuous manner along the U-shaped channel, prolonging the heat exchange time and increasing the temperature of the fresh air outlet. Conversely, it adjusts the angle of the air guide plate to achieve adaptive control. In the fourth state, both sides of the air guide plate are adjusted to 25°-35°, and the exhaust gas is forced to turn back multiple times along the wall of the U-shaped channel. This results in the longest path, the longest residence time, and the most efficient heat exchange, making it especially suitable for occasions where the exhaust gas temperature is low and deep waste heat recovery is required.

[0016] 2. This plate heat exchanger can adjust the angle of the heat exchange plates according to the outlet air temperature. The four angle states cover a variety of working conditions, from fast straight-through (low heat exchange, large flow) to tortuous path (high efficiency heat exchange), as well as asymmetrical modes such as two-sided deflection, which can flexibly adapt to changes in exhaust gas volume and airflow adjustment after local ash accumulation. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a top view of the structure of the present invention; Figure 3 This is a schematic diagram of the heat exchange plate mechanism of the present invention; Figure 4 This is a front view of the heat exchange plate mechanism of the present invention; Figure 5 This is a cross-sectional view of the heat exchange plate mechanism of the present invention; Figure 6 For the present invention Figure 3Enlarged view of the structure at point A in the middle.

[0018] In the diagram: 1. Outer casing; 2. Exhaust gas inlet duct; 3. Exhaust gas outlet duct; 4. Fresh air fan; 5. Fresh air outlet duct; 6. First temperature sensor; 7. Second temperature sensor; 8. Third temperature sensor; 9. Fourth temperature sensor; 10. Base; 11. Top seat; 12. Supporting and reinforcing rod; 13. First air guide plate; 14. First synchronizing rod; 15. Second air guide plate; 16. Second synchronizing rod; 17. Elastic reset component; 18. First heat exchange plate; 19. Second heat exchange plate; 20. Reel; 21. Motor; 22. Rotating shaft; 23. Cable; 24. Guide wheel. Detailed Implementation

[0019] This invention provides a plate heat exchanger whose plate angle can be adjusted according to the outlet air temperature, such as... Figures 1 to 6 As shown, it includes an outer shell 1, an exhaust gas side duct, a fresh air side duct, a heat exchange plate mechanism, an air guide plate assembly, and a drive mechanism.

[0020] The outer casing 1 is a rectangular box, with exhaust gas inlet pipe 2 and exhaust gas outlet pipe 3 fixedly connected to the left and right sides, respectively. A fresh air fan 4 (blowing air into the heat exchanger) and a fresh air outlet pipe 5 are fixedly connected to the front and rear sides, respectively. The high-temperature exhaust gas (approximately 120-180℃) discharged from the stenter enters the heat exchanger through the exhaust gas inlet pipe 2, exchanges heat with the fresh air, and is then discharged from the exhaust gas outlet pipe 3 (temperature reduced to 60-80℃); the fresh air enters the stenter after preheating.

[0021] The outer casing 1 houses a heat exchange plate mechanism, including a base 10, a top seat 11, multiple supporting and reinforcing rods 12, a first heat exchange plate 18, and a second heat exchange plate 19. The base 10 and top seat 11 are fixedly connected by vertical supporting and reinforcing rods 12, forming a frame. Both the first heat exchange plate 18 and the second heat exchange plate 19 have U-shaped groove structures, arranged in an alternating layer between the base and the top seat. The U-shaped groove opening of the first heat exchange plate 18 faces left and right, forming a first heat exchange air duct, with its two ends connected to the exhaust gas inlet pipe 2 and the exhaust gas outlet pipe 3, respectively. The U-shaped groove opening of the second heat exchange plate 19 faces front and back, forming a second heat exchange air duct, with its two ends connected to the fresh air fan 4 and the fresh air outlet pipe 5, respectively. The height (U-shaped groove depth) of the first heat exchange plate 18 is more than twice the height of the second heat exchange plate 19 (in this embodiment, the height of the first heat exchange plate is 200mm and the height of the second heat exchange plate is 80mm) to increase the heat exchange area on the exhaust gas side and compensate for the decrease in heat transfer coefficient caused by the oil film in the exhaust gas.

[0022] Each first heat exchange plate 18 has a first air guide plate 13 and a second air guide plate 15 rotatably connected to its opening (i.e., the exhaust gas inlet side and outlet side). The outer sides of the multiple first air guide plates 13 are connected by a vertical first synchronizing rod 14, and each air guide plate is rotatably connected to the synchronizing rod to ensure that the air guide plates in the same row rotate synchronously. Similarly, the multiple second air guide plates 15 are connected by a second synchronizing rod 16. The top seat 11 is provided with two independent drive mechanisms, which drive the first synchronizing rod 14 and the second synchronizing rod 16 respectively, thereby controlling the angle of the air guide plates on both sides.

[0023] The drive mechanism includes a motor 21, a rotating shaft 22, a take-up reel 20, a cable 23, and a guide wheel 24. The motor 21 is fixed inside the top seat 11, and its output shaft is connected to the rotating shaft 22. Two take-up reels 20 are fixed on the rotating shaft 22, and the guide wheel 24 is mounted on the side wall of the top seat 11. One end of the cable 23 is wound and fixed to the take-up reel 20, and the other end passes over the guide wheel 24 and is fixedly connected to the outer end of the corresponding air guide plate (or the end of the synchronizing rod). When the motor 21 rotates forward, the take-up reel 20 tightens the cable, pulling the air guide plate to rotate; when rotating in reverse, the cable is released, and the air guide plate is reset by the elastic reset element 17 (spring). This drive method occupies little space, is suitable for narrow spaces inside the top seat, and the cable is resistant to high temperatures and oil stains.

[0024] A first temperature sensor 6 and a second temperature sensor 7 are installed on the exhaust gas inlet duct 2 and exhaust gas outlet duct 3, respectively; a third temperature sensor 8 and a fourth temperature sensor 9 are installed on the fresh air fan 4 and fresh air outlet duct 5, respectively. The control system (PLC) collects the four temperature data in real time. When the temperature difference between the exhaust gas inlet and outlet is less than 30°C (indicating that the waste heat of the exhaust gas is not being fully utilized), the control system starts the corresponding motor, driving the first guide vane 13 (or the second guide vane 15) to rotate to a position of 25°~35° with the airflow direction, causing the exhaust gas to flow in a tortuous manner along the U-shaped channel, prolonging the heat exchange time and increasing the fresh air outlet temperature. Conversely, when the temperature difference is large, the angle of the guide vane is increased to increase the flow rate.

[0025] When the temperature difference between the inlet and outlet of the exhaust gas is less than 30°C (indicating that the waste heat of the exhaust gas is not being fully utilized), the control system starts the corresponding motor, driving the first guide vane 13 to rotate to a position of 25°~35° with the airflow direction, causing the exhaust gas to flow in a tortuous manner along the U-shaped channel, extending the heat exchange time and improving the heat exchange efficiency. Similarly, when the temperature difference between the inlet and outlet of the fresh air (i.e., the difference between the third temperature sensor 8 and the fourth temperature sensor 9) is less than 30°C, it indicates that the fresh air is not absorbing enough heat from the exhaust gas, and the fresh air outlet temperature is too low. At this time, the control system starts another motor, driving the second guide vane 15 to rotate to a position of 25°~35° with the airflow direction, increasing the flow resistance on the exhaust gas side, forcing the exhaust gas to contact the heat exchange plate wall more fully in the U-shaped channel, extending the heat exchange path, thereby increasing the fresh air outlet temperature. When the temperature difference is greater than 30°C, the guide vane gradually opens to 0°, reducing resistance, increasing airflow, and preventing the fresh air from overheating or increasing system energy consumption.

[0026] Depending on the exhaust gas flow rate, temperature, and heat exchange requirements of the stenter, the air guide plate can be in the following four states: State 1 (Fully Open 0°): Both the first guide vane 13 and the second guide vane 15 are rotated to 0° (parallel to the airflow direction). At this time, the cross-sectional area of ​​the exhaust gas passage is the largest, and the exhaust gas passes through directly and quickly, resulting in the largest flow rate. However, the contact time between the gas and the heat exchange plate wall is short, leading to the least efficient heat exchange. This state is suitable for special operating conditions where the exhaust gas temperature is extremely high, rapid heat removal is required, or the demand for fresh air is very high.

[0027] State 2 (Left-side deflection): The first guide vane 13 rotates to 25°~35° (partially closed), while the second guide vane 15 remains at 0°. Exhaust gas mainly passes through the right-side channel, increasing resistance on the left side and creating an asymmetrical airflow. This state can alter the airflow distribution, adapting to situations where localized fouling occurs on the heat exchange plates or where heat load adjustments are required.

[0028] State 3 (Right-side deflection): The first guide vane 13 remains at 0°, and the second guide vane 15 rotates to 25°~35°. In contrast to State 2, the exhaust gas deflects to the left.

[0029] State 4 (Dual Adjustment): Both the first guide vane 13 and the second guide vane 15 are rotated to 25°~35°. At this state, after the exhaust gas enters the U-shaped heat exchange channel, it is obstructed by the guide vanes on both sides and cannot pass through in a straight line. It is forced to flow in a tortuous manner along the heat exchange plate wall, significantly extending the path and increasing the residence time, resulting in the most efficient heat exchange and the highest outlet air temperature. This state is the optimal operating mode under normal waste heat recovery conditions.

[0030] One end of the elastic reset element 17 (coil spring) is fixed to the base 10, and the other end is connected to the air guide plate or synchronizing rod. It provides reset torque and suppresses vibration caused by airflow impact. There are generally four elastic reset elements 17 on each side. The support and reinforcing rod 12 passes through the mounting holes on the first and second heat exchange plates and plays a role in positioning and supporting the heat exchange plates to prevent deformation.

[0031] Working principle High-temperature exhaust gas enters the U-shaped groove of the first heat exchange plate 18 through the inlet duct, flowing laterally across the surface of the heat exchange plate and transferring heat to the wall. Fresh air is delivered by the fresh air fan 4 into the U-shaped groove of the second heat exchange plate 19, flowing longitudinally across the other side of the heat exchange plate, absorbing heat, and then being discharged from the outlet duct. A temperature sensor monitors the temperature difference between the inlet and outlet air in real time, and the control system adjusts the angle of the exhaust gas-side guide vane according to the temperature difference. Specifically, when the temperature difference between the fresh air inlet and outlet is less than 30°C, the second guide vane 15 is rotated to 25°-35° to increase the heat exchange path length; when the temperature difference between the exhaust gas inlet and outlet is less than 30°C, the first guide vane 13 is rotated to the same angle. Conversely, when the temperature difference is large, the guide vane angle is increased to increase the flow rate, changing the exhaust gas flow path and the effective heat exchange area. When the temperature difference between the exhaust gas inlet and outlet is small, adjust the air guide plate to state four (double 25°-35°). The exhaust gas flows along the U-shaped channel in a tortuous manner, resulting in the longest heat exchange path and the most efficient heat exchange, thereby increasing the temperature of the fresh air outlet. When the temperature difference is large, gradually open the air guide plate to state one to increase the exhaust gas flow and prevent the fresh air from overheating. In addition, states two and three can be used to adjust the airflow uniformity or assist in blowing away localized dust accumulation.

[0032] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A plate heat exchanger with adjustable heat exchange plate angle according to outlet air temperature, comprising a shell (1), characterized in that: The outer shell (1) is fixedly connected to the left and right sides with an exhaust gas inlet pipe (2) and an exhaust gas outlet pipe (3), respectively. The outer shell (1) is fixedly connected to the front and rear sides with a fresh air fan (4) and a fresh air outlet pipe (5), respectively. A heat exchange plate mechanism is fixedly connected inside the outer shell (1). The heat exchange plate mechanism includes a base (10), a top seat (11), a support and reinforcing rod (12), a first heat exchange plate (18), and a second heat exchange plate (19). The base (10) and the top seat (11) are fixedly connected by the support and reinforcing rod (12); the first heat exchange plate (18) and the second heat exchange plate (19) are alternately arranged between the base (10) and the top seat (11), and both are U-shaped groove structures; a first heat exchange air duct is formed in the first heat exchange plate (18), and its two ends are respectively connected to the exhaust gas inlet pipe (2) and the exhaust gas outlet pipe (3); a second heat exchange air duct is formed in the second heat exchange plate (19), and its two ends are respectively connected to the fresh air fan (4) and the fresh air outlet pipe (5).

2. The plate heat exchanger according to claim 1, characterized in that: The height of the first heat exchange plate (18) is more than twice the height of the second heat exchange plate (19).

3. The plate heat exchanger according to claim 1, characterized in that: Each of the first heat exchange plates (18) has a first air guide plate (13) and a second air guide plate (15) rotatably connected to both sides of the opening. The outer sides of multiple first air guide plates (13) are connected to a vertical first synchronization rod (14), and each first air guide plate (13) is rotatably connected to the first synchronization rod (14); the outer sides of multiple second air guide plates (15) are connected to a vertical second synchronization rod (16), and each second air guide plate (15) is rotatably connected to the second synchronization rod (16); the top seat (11) is provided with two driving mechanisms, which are respectively connected to the first air guide plate (13) and the second air guide plate (15).

4. The plate heat exchanger according to claim 3, characterized in that: The drive mechanism includes a motor (21), a rotating shaft (22), a take-up reel (20), a cable (23), and a guide wheel (24). The motor (21) is fixed inside the top seat (11), and its output end is connected to the rotating shaft (22) for transmission. Two take-up wheels (20) are fixedly connected to the rotating shaft (22), and the guide wheel (24) is installed on the top seat (11). One end of the cable (23) is fixedly connected to the take-up wheel (20), and the other end passes around the guide wheel (24) and is fixedly connected to the outer end of the corresponding air guide plate.

5. The plate heat exchanger according to claim 3, characterized in that: The exhaust gas inlet pipe (2) and the exhaust gas outlet pipe (3) are respectively fixedly connected to a first temperature sensor (6) and a second temperature sensor (7); When the temperature difference between the first temperature sensor (6) and the second temperature sensor (7) is configured to be less than 30°C, the driving mechanism drives the first air guide plate (13) to rotate to a position of 25° to 35° with respect to the airflow direction.

6. The plate heat exchanger according to claim 3, characterized in that: The fresh air fan (4) and the fresh air outlet pipe (5) are respectively fixedly connected to a third temperature sensor (8) and a fourth temperature sensor (9). When the temperature difference between the third temperature sensor (8) and the fourth temperature sensor (9) is configured to be less than 30°C, the driving mechanism drives the second air guide plate (15) to rotate to a position of 25° to 35° with respect to the airflow direction.

7. The plate heat exchanger according to claim 3, characterized in that: The lengths of the first air guide plate (13) and the second air guide plate (15) are equal.

8. The plate heat exchanger according to claim 3, characterized in that: Both sides of the base (10) are provided with elastic reset members (17). One end of the elastic reset member (17) is fixedly connected to the base (10), and the other end is fixedly connected to the corresponding first air guide plate (13) or second air guide plate (15) to suppress the shaking of the air guide plate when the airflow fluctuates.

9. The plate heat exchanger according to claim 1, characterized in that: The number of the support and reinforcement rods (12) is multiple. The first heat exchange plate (18) and the second heat exchange plate (19) are each provided with mounting holes corresponding to the support and reinforcement rods (12). The first heat exchange plate (18) and the second heat exchange plate (19) are inserted through the support and reinforcement rods (12).

10. The plate heat exchanger according to claim 3, characterized in that: The first air guide plate (13) and the second air guide plate (15) have the following four working angle states: First state: The first air guide plate (13) and the second air guide plate (15) are both rotated to the fully open position with 0° to the airflow direction. At this time, the cross-sectional area of ​​the exhaust gas channel is the largest and the flow rate is the largest, but the exhaust gas direct heat exchange time is the shortest and the heat exchange efficiency is the lowest. Second state: The first guide vane (13) is rotated to an adjustment position of 25° to 35° with the airflow direction, and the second guide vane (15) remains fully open. At this time, one side of the exhaust gas passage is blocked, forming an asymmetrical airflow. Third state: The first guide vane (13) remains fully open, and the second guide vane (15) is rotated to an adjustment position of 25° to 35° with the airflow direction. At this time, the other side of the exhaust gas passage is blocked, forming a reverse asymmetric airflow. Fourth state: The first guide plate (13) and the second guide plate (15) are both rotated to an adjustment position of 25° to 35° with the airflow direction. At this time, the exhaust gas is forced to flow along the U-shaped heat exchange channel in a tortuous manner, with the longest heat exchange path, the longest residence time, and the most sufficient heat exchange.

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