Exhaust stack outlet reducer

Abstract

The utility model discloses an exhaust cylinder outlet taper device, including a plurality of blades and drive part, the blade is located in the exhaust cylinder, a plurality of blades are arranged in the ring arrangement with the axis of the exhaust cylinder as the center, and the adjacent two blades are partially overlapped in turn, the root end of blade is rotatably connected with the inner wall of exhaust cylinder, the drive part is connected with the free end of one blade, and the blade can be driven to overturn along the root end. When the exhaust capacity changes, the drive part pushes the selected blade to overturn around the root end, and since the blades are connected with each other through the overlapping structure, the rotation of a single blade can drive the whole circle of blades to adjust the unfolding angle synchronously, and the change of the unfolding angle of the blade directly affects the effective flow area of the exhaust cylinder outlet.

Description

Technical Field

[0001] This utility model relates to the field of industrial ventilation equipment technology, and in particular to a device for a tapered outlet of an exhaust stack. Background Technology

[0002] In industrial production and laboratory environments, the emission of toxic and harmful gases must strictly comply with national standards such as the "Integrated Emission Standard for Air Pollutants" (GB16297). In locations where large quantities of toxic gases, explosive gases, or dust may be suddenly released, emergency ventilation systems must be installed according to process design requirements to increase ventilation volume and dilute the gases before emission. The height of the exhaust stack should meet the requirements of current national air pollution emission standards and should not be less than 15m. The recommended exhaust stack outlet velocity is 15m / s to 20m / s. Typically, a fixed tapered pipe is installed at the top of the exhaust stack to maintain the exhaust stack outlet velocity within the range of 15m / s to 20m / s.

[0003] Because emergency ventilation systems are typically shared with mechanical ventilation systems, daily ventilation volume is usually only half that of emergency ventilation. Laboratory fume hoods use variable air volume (VAV) designs for energy conservation, with the minimum VAV control of the fan possibly being about one-third of the total VAV. This results in the outlet velocity of fixed-diameter exhaust stacks deviating significantly from the standard range. This velocity fluctuation not only affects pollutant dispersion but may also lead to pollutant accumulation near the exhaust outlet due to insufficient velocity, or unnecessary energy waste due to excessive velocity.

[0004] Existing technologies lack devices that can adjust the outlet cross-sectional area according to real-time air volume, making it difficult to continuously meet emission standards under varying operating conditions. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a variable diameter exhaust pipe outlet tapering device that can adjust the wind speed at the exhaust pipe outlet.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: A tapered exhaust outlet device, comprising: Multiple blades are located inside the exhaust stack, arranged circumferentially around the axis of the exhaust stack, with adjacent blades partially overlapping. The root ends of the blades are rotatably connected to the inner wall of the exhaust stack. The drive unit, connected to the free end of one of the blades, is capable of driving the blade to rotate along its root end.

[0007] A further technical solution is that the driving unit includes: A fixed bracket is attached to the inner wall of the exhaust pipe; and The telescopic rod has its fixed end rotatably fixed to a fixed bracket and located on the axis of the exhaust pipe. The telescopic end of the telescopic rod is rotatably fixed to the free end of the inner side of the blade.

[0008] A further technical solution is that the driving unit further includes: The airflow sensor is located inside the exhaust stack; and The controller has its signal input terminal connected to the air volume sensor and its signal output terminal connected to the telescopic rod.

[0009] A further technical solution is that the blade has an arc-shaped sheet structure, and the curvature of the blade matches the inner wall of the exhaust pipe.

[0010] A further technical solution is that the blades are made of stainless steel.

[0011] A further technical solution is that the length of the blade is smaller than the radius of the inner cavity of the exhaust duct.

[0012] A further technical solution is that a support ring is fixed on the inner wall of the exhaust pipe, and multiple insertion holes are provided on the support ring. The inner edge of the support ring corresponding to the insertion hole is a rotating shaft section, and the cross-section of the rotating shaft section is circular. The root end of the blade is provided with a pin. After the pin is inserted into the socket, the pin bends and hooks with the rotating shaft section, so that the blade can rotate around the rotating shaft section.

[0013] A further technical solution is that the connection between the pin and the shaft section is an arc-shaped section.

[0014] A further technical solution is that the pin, after being bent, forms an angle of 0° to 90° with the blade.

[0015] A further technical solution is that a sealing layer is fixed on the end face of the support ring away from the blade.

[0016] The beneficial effects of adopting the above technical solution are as follows: When the exhaust volume changes, the drive unit pushes the selected blade to rotate around the root end. Since the blades are interconnected through the overlapping structure, the rotation of a single blade will drive the entire circle (all) blades to adjust their unfolding angle synchronously. The change in the unfolding angle of the blades directly affects the effective flow area of ​​the exhaust pipe outlet.

[0017] By incorporating a ring of blades that can rotate towards the center of the exhaust stack, the size of the exhaust stack outlet is dynamically adjusted, effectively solving the technical challenge of the exhaust stack outlet velocity deviating from the standard range under variable air volume conditions. The interlocking adjustment mechanism formed by the overlapping blades can respond quickly to real-time air volume. The separate, interconnected blades ensure both adjustment sensitivity and maintain airflow stability, ensuring that the outlet velocity remains within the set range. This guarantees emission compliance while avoiding pollutant accumulation due to insufficient airflow or energy waste caused by excessive airflow. Attached Figure Description

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0019] Figure 1 This is a top view of the structure of the present invention when it is folded to a certain set position; Figure 2 This is a top view of the structure of this utility model in its fully opened state; Figure 3 This is a schematic diagram of the main structure of the present invention when it is folded to a certain set position; Figure 4 This is a schematic diagram of the blade structure in this utility model (before the pin is bent); Figure 5 This is a schematic diagram of the support ring structure in this utility model. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Many specific details are set forth in the following description to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0021] In the description of this utility model, unless otherwise stated, the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not 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] Example 1: like Figures 1-4 As shown, an exhaust pipe outlet tapering device uses a mechanical structure to change the cross-sectional area of ​​the exhaust pipe 1 outlet, thereby maintaining a constant wind speed. The exhaust pipe outlet tapering device includes multiple blades 3 and a drive unit.

[0023] Multiple blades 3 are located inside the exhaust pipe 1. The multiple blades 3 are arranged in a ring around the axis of the exhaust pipe 1. Adjacent blades 3 partially overlap one another. The multiple blades 3 always form a ring-shaped, continuous closed surface. The root end of the blades 3 is rotatably connected to the inner wall of the exhaust pipe 1.

[0024] The drive unit is connected to the free end of one of the blades 3, and can drive the blade 3 to rotate along its root end, thereby driving the entire set of blades 3 to move together through one blade 3.

[0025] Blade 3 is an arc-shaped, sheet-like metal component with a specific installation method. It can be made by stamping thin stainless steel sheets. Stainless steel has high structural strength, preventing deformation and jamming of blade 3 due to thermal expansion. The curvature of blade 3 matches the curvature of the inner wall of exhaust pipe 1, allowing it to fit against the inner wall of exhaust pipe 1 when rotated outwards to its maximum position, ensuring all gas passes through the outlet on the inner side of blade 3. The length of blade 3 is less than the radius of the exhaust pipe's inner cavity. Even when blade 3 is rotated inwards to its minimum position, the exhaust pipe still has an outlet of a certain size, preventing accidental closure of the exhaust pipe outlet due to operational errors.

[0026] The drive unit is a power mechanism that can output mechanical motion. Specifically, it can be implemented by an electric push rod or a hydraulic cylinder. The linear motion of the drive unit is converted into the rotational motion of the blade 3.

[0027] When the exhaust volume changes, the drive unit pushes the selected blade 3 to rotate around its root end. Because the blades 3 are interconnected through an overlapping structure, the rotation of a single blade 3 causes all the blades 3 to synchronously adjust their unfolding angle. This change in the unfolding angle directly affects the effective flow area at the outlet of the exhaust stack 1. When the air volume decreases, the angle at which the blades 3 rotate towards the center (inwards) of the exhaust stack 1 increases, and the shape formed by all the blades 3 approaches a cone shape, thus reducing the outlet area. Conversely, when the air volume increases, the angle at which the blades 3 rotate towards the center of the exhaust stack 1 decreases, expanding the outlet area, thereby achieving automatic stabilization of the outlet air velocity. When the blades 3 rotate outwards and fit against the inner wall of the exhaust stack 1, the shape formed by all the blades 3 approaches a cylinder shape, and the opening of the tapering device at the exhaust stack outlet is at its maximum.

[0028] This embodiment achieves dynamic adjustment of the outlet size of the exhaust stack 1 by setting a ring of blades 3 that can rotate towards the center of the exhaust stack 1, effectively solving the technical problem of the outlet wind speed of the exhaust stack 1 deviating from the standard range under variable air volume conditions. The linkage adjustment mechanism formed by the overlapping of the blades 3 can respond quickly according to the real-time air volume. The separate linkage of the blades 3 can ensure both adjustment sensitivity and maintain the stability of airflow, ensuring that the outlet wind speed is always maintained within the set range. While ensuring emission compliance, it avoids pollutant accumulation due to insufficient wind speed or energy waste caused by excessive wind speed.

[0029] Example 2: The drive unit includes a fixed bracket 5 and a telescopic rod 4. The fixed bracket 5 is fixed to the inner wall of the exhaust pipe 1. The fixed end of the telescopic rod 4 is rotatably fixed to the fixed bracket 5 and located on the axis of the exhaust pipe 1. The telescopic end of the telescopic rod 4 is rotatably fixed to the free end of the inner side of the blade 3.

[0030] The fixed bracket 5 is a support structure welded to the inner wall of the exhaust stack 1. Specifically, it can be implemented using a cross-shaped frame welded from angle steel, providing a stable installation foundation for the telescopic rod 4. The telescopic rod 4 can utilize existing linear motion mechanisms such as electric actuators or hydraulic rods, changing its telescopic length through linear movement at its end. Both ends of the telescopic rod 4 are connected to corresponding components via universal joints, achieving a rotatable connection between the two ends of the telescopic rod 4 and the corresponding components. A universal joint is a hinged component with two orthogonal rotational degrees of freedom; specifically, a cross-type universal joint can be used, allowing the telescopic rod 4 to undergo angular compensation in three-dimensional space during extension and retraction.

[0031] The fixed bracket 5 is welded to the middle of the inner wall of the exhaust pipe 1. The fixed end of the telescopic rod 4 is installed at the center of the fixed bracket 5 via a universal joint. The telescopic end of the telescopic rod 4 is connected to the free end of the blade 3 via the universal joint. When the telescopic rod 4 shortens, it causes the connected blade 3 to rotate around its root toward the center (inward) of the exhaust pipe 1. Adjacent blades 3 rotate in tandem, causing the exhaust pipe 1 outlet to form a tapering opening (outlet narrowing). When the telescopic rod 4 extends, it causes the connected blade 3 to rotate around its root toward the outward, causing adjacent blades 3 to rotate in tandem, causing the exhaust pipe 1 outlet to widen. The universal joint allows the telescopic rod 4 to adaptively adjust the connection angle during movement, avoiding motion interference.

[0032] The blades 3 are driven by the telescopic rod 4 to form a dynamic tapering orifice. Combined with the multi-directional freedom of the universal joint, the outlet diameter can be adjusted in real time according to the change of the fan air volume, effectively maintaining the outlet air velocity within the standard range.

[0033] Through the above technical solution, this embodiment can automatically adjust the outlet cross-sectional area of ​​the exhaust stack 1 according to the actual air volume of the ventilation system, so that the outlet air velocity is always maintained within the legal standard range. The combination design of the telescopic rod 4 and the universal joint eliminates mechanical motion interference, ensuring the smooth and reliable adjustment process of the blade 3.

[0034] Example 3: The drive unit also includes an air volume sensor and a controller. The signal input terminal of the controller is connected to the air volume sensor, and the signal output terminal of the controller is connected to the telescopic rod 4.

[0035] The airflow sensor is a component used to monitor the gas flow rate inside the exhaust stack 1 in real time. It can be implemented using a thermal flow meter or a differential pressure flow meter, and its installation position can be set in the stable airflow area inside the exhaust stack 1. The controller is a computing unit that receives sensor signals and outputs control commands. It can be implemented using a PLC or a microcontroller. It converts the flow signal into the displacement of the telescopic rod 4 through a preset algorithm (which is existing technology).

[0036] Specifically, a flow sensor continuously collects gas flow data within the exhaust stack 1 and transmits the signal to the controller. The controller compares the received flow data with a preset threshold range. When the flow rate is detected to be lower or higher than the set value, it generates a corresponding control command to drive the telescopic rod 4 to extend or retract. The displacement of the telescopic rod 4 changes the opening and closing angle of the blades 3 through mechanical linkage, thereby adjusting the effective flow area at the outlet of the exhaust stack 1. For example, when the airflow decreases, the controller controls the telescopic rod 4 to retract, causing the blades 3 to close and enlarge, reducing the outlet cross-sectional area to maintain the airflow; when the airflow increases, the operation is reversed.

[0037] This embodiment achieves dynamic adjustment of the outlet diameter through real-time monitoring and closed-loop control, establishes a direct correlation between the flow signal and the control actuator, improves the system's adaptability to different operating conditions, and avoids the operational lag of manual adjustment. It can automatically adjust the outlet cross-sectional area of ​​the exhaust stack 1 when the air volume changes, so that the outlet air velocity is stably maintained within the compliant range.

[0038] Example 4: A support ring 2 is fixed on the inner wall of the exhaust pipe 1, such as Figure 5 As shown, the support ring 2 has multiple insertion holes 7, and the inner edge of the support ring 2 corresponding to each insertion hole 7 is a rotating shaft section 201, the cross-section of which is circular. Figure 4 As shown, the root end of the blade 3 is provided with a pin 6. After the pin 6 is inserted into the socket 7, the pin 6 is bent and hooked to the rotating shaft section 201, so that the blade 3 can rotate around the rotating shaft section 201.

[0039] The support ring 2 is an annular structure fixed to the inner wall of the exhaust pipe 1, specifically by welding metal rings. The support ring 2 provides the mounting base for the blade 3. The insertion hole 7 is a hole in the support ring 2 used to accommodate the insertion pin 6 of the blade 3. The rotating shaft section 201 is a cylindrical structure formed on the inner edge of the support ring 2 corresponding to the insertion hole 7, serving as the axis of rotation for the blade 3. The insertion pin 6 is an extension structure at the root end of the blade 3. After the insertion pin 6 is inserted into the insertion hole 7, it is mechanically locked by bending, allowing the blade 3 to form a rotatable connection with the support ring 2. When the drive unit rotates a blade 3, the mating structure between the insertion pin 6 and the rotating shaft section 201 allows the blade 3 to rotate around its axis, while the bent insertion pin 6 provides a mechanical limit, preventing the blade 3 from dislodging from the insertion hole 7.

[0040] By connecting the pin 6 to the rotating shaft section 201, rapid assembly and disassembly of a single blade 3 can be achieved while ensuring reliable connection. Furthermore, the connection point between the pin 6 and the rotating shaft section 201 is preferably an arc-shaped section, forming a curved transition area where the pin 6 contacts the rotating shaft section 201. This arc-shaped section reduces the contact stress between the pin 6 and the cylindrical surface of the rotating shaft section 201, thus reducing frictional resistance during rotation.

[0041] Through the above technical solution, a detachable rotatable connection between the blade 3 and the inner wall of the exhaust pipe 1 is achieved. The bending and locking of the pin 6 avoids the use of additional fasteners and simplifies the installation process. The cylindrical design of the rotating shaft section 201 ensures the stability of the blade 3 during rotation, making the tapering adjustment process smoother and more reliable, ensuring that the blade 3 maintains stable rotation during frequent adjustments, and extending the service life of the device.

[0042] Example 5: When the insertion pin 6 is bent, it forms an angle of 0° to 90° with the blade 3; when the angle is 90°, the insertion pin 6 is bent perpendicular to the blade 3; when the angle is 0°, the insertion pin 6 is bent parallel to the blade 3.

[0043] The bending of pin 6 involves bending the end of pin 6, which is inserted into the socket 7 of the support ring 2, to form a hook-like structure that connects to the rotating shaft section. The 0°~90° angle range allows for both the maximum and minimum opening states of the blades 3 after rotation, adapting to the exhaust port diameter adjustment requirements under different airflow conditions. It also maintains connection stability when the blades 3 are subjected to airflow, preventing pin 6 from detaching from the socket 7. The length of the hook-shaped structure after the pin 6 is bent can be 1.2-1.5 times the diameter of the shaft section to ensure that the blade 3 remains stably connected during rotation. A lubricating coating, such as polytetrafluoroethylene, can be applied to the surface of the shaft section on the support ring 2 to reduce rotational friction resistance.

[0044] Example 6: A sealing layer is fixed on the end face of the support ring 2 away from the blade 3. Preferably, the inner edge of the sealing layer is tightly fitted to the inner wall of the exhaust pipe 1.

[0045] The sealing layer is a flexible material layer covering the end face of the support ring 2. Specifically, it can be made of rubber or silicone and is fixed to the lower end face of the support ring 2 by adhesive or snap-fit. Its function is to prevent gas leakage from the gaps between the support ring 2 and the inner wall of the exhaust pipe 1, and from the insertion hole 7, ensuring that the airflow completely passes through the converging channel formed by the blade 3. It can adapt to pressure fluctuations caused by changes in airflow within the exhaust pipe 1, avoiding airflow leakage problems caused by the installation gap of the support ring 2 and the insertion hole 7, thereby ensuring the accuracy of the outlet airflow speed adjustment. This embodiment adds a sealing layer to form a continuous closed surface between the support ring 2 and the inner wall of the exhaust pipe 1, while simultaneously sealing the insertion hole 7, eliminating leakage channels and ensuring that the airflow is completely controlled by the tapered structure formed by the blades 3, thus improving the stability of wind speed regulation. For variable air volume systems or emergency ventilation systems with frequent air volume changes, this ensures that the exhaust gas flow rate meets national standards.

[0046] The above are merely preferred embodiments of this utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

Claims

1. A tapered outlet device for an exhaust stack, characterized in that, include: Multiple blades are located inside the exhaust stack, arranged circumferentially around the axis of the exhaust stack, with adjacent blades partially overlapping. The root ends of the blades are rotatably connected to the inner wall of the exhaust stack. The drive unit, connected to the free end of one of the blades, is capable of driving the blade to rotate along its root end.

2. The exhaust stack outlet tapering device according to claim 1, characterized in that, The drive unit includes: A fixed bracket is attached to the inner wall of the exhaust pipe; and The telescopic rod has its fixed end rotatably fixed to a fixed bracket and located on the axis of the exhaust pipe. The telescopic end of the telescopic rod is rotatably fixed to the free end of the inner side of the blade.

3. The exhaust stack outlet tapering device according to claim 2, characterized in that, The drive unit also includes: The airflow sensor is installed inside the exhaust pipe; and The controller has its signal input terminal connected to the air volume sensor and its signal output terminal connected to the telescopic rod.

4. The exhaust stack outlet tapering device according to claim 1, characterized in that, The blades have an arc-shaped, plate-like structure, and the curvature of the blades matches the inner wall of the exhaust pipe.

5. The exhaust stack outlet tapering device according to claim 1, characterized in that, The blades are made of stainless steel.

6. The exhaust stack outlet tapering device according to claim 1, characterized in that, The length of the blade is less than the radius of the inner cavity of the exhaust duct.

7. The exhaust stack outlet tapering device according to claim 1, characterized in that, A support ring is fixed on the inner wall of the exhaust pipe. The support ring has multiple insertion holes. The inner edge of the support ring corresponding to the insertion holes is a rotating shaft section. The cross-section of the rotating shaft section is circular. The root end of the blade is provided with a pin. After the pin is inserted into the socket, the pin bends and hooks with the shaft section, so that the blade can rotate around the shaft section.

8. The exhaust stack outlet tapering device according to claim 7, characterized in that, The connection between the pin and the shaft section is an arc-shaped section.

9. The exhaust stack outlet tapering device according to claim 7, characterized in that, The pins are bent at an angle of 0° to 90° to the blade.

10. The exhaust stack outlet tapering device according to claim 7, characterized in that, A sealing layer is fixed on the end face of the support ring away from the blade.

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