Fan equipment damper mechanism with adjustable stroke and standby limit

Abstract

A damper mechanism for a fan with a spare limit for opening adjustment stroke is provided. The center lines of the rotating arm (4) and the handle (13) are perpendicular to the center line of the damper shaft (3) and are mounted on the damper shaft (3). The outer end of the handle (13) is connected to the actuator (2). The other end of the handle (13) extends outward to connect to the lever (16). The first limit switch (9) and the second limit switch (10) are respectively installed at both ends of the rotating arc trajectory of the outer end of the lever (16). The top of the first limit switch (9) and the second limit switch (10) are respectively provided with the first limit contact (11) and the second limit contact (12). The mechanism integrates dual protection of electrical feedback and mechanical limit, controls the damper action, provides stable opening control, and ensures system reliability. Seamless switching in case of failure. No manual intervention is required throughout the process. It forms a closed-loop adjustment. It supports long-term operation and adjustment of the fan. It solves the problems of low adjustment accuracy, poor limit reliability, and lack of fault redundancy in the existing damper mechanism. It achieves high reliability and stable control of the damper opening and closing stroke, and the structure is simple and easy to promote.

Description

Technical Field

[0001] This utility model belongs to the technical field of ventilation or airflow distribution equipment in mines or tunnels (IPC classification E21F1 / 10), specifically the field of industrial ventilation equipment technology. In particular, it relates to an improved and optimized technology for safe and stable control of the opening stroke of the damper mechanism of a fan device, which is especially suitable for occasions requiring high-precision airflow control and fault redundancy. Background Technology

[0002] As more and more fan equipment needs to control air volume and air pressure, in actual use, damage to the internal limit switches of the actuator can easily lead to inaccurate product process parameters, resulting in a decrease in yield.

[0003] According to the latest industry trends, the existing wind turbine damper travel technology shows the following development trends:

[0004] 1) Intelligent control technology: Luoyang Beibo Sanyuan Flow Fan Technology Co., Ltd. published an invention patent for "a fan damper" on March 14, 2025, representing the industry's continuous innovation in damper technology.

[0005] 2) Remote control integration: The ventilation control device for coal mines adopts button-type local remote control technology, which realizes local and remote control of the air door by integrating advanced control system and sensors.

[0006] 3) Multi-door linkage design: The mine pneumatic interlocking air door adopts a four-door linkage two-way trolley design. When one set of air doors is opened, the other set of air doors is automatically locked, which improves ventilation efficiency and safety.

[0007] Patent application 201120552178.9 discloses an electric damper for a fan, mainly designed to address the numerous drawbacks of existing dampers for mine axial flow ventilation fans that utilize wind pressure to start. This utility model's electric damper for a fan includes a fan with a duct, a damper connected to the duct, and an electric connecting rod disposed within the duct and hinged to a hinge block on the damper. The duct is connected to the damper via a door hinge mounted thereon, and a limit switch is also provided within the duct. This utility model's electric damper for a fan features a simple and compact structure, electric control, and good controllability, effectively ensuring the timely opening and closing of the damper and its safe operation.

[0008] Existing damper stroke control devices have shortcomings in terms of accuracy, response speed, intelligence, and environmental adaptability, making it difficult to meet the demands of modern industrial automation, energy conservation, and complex operating conditions. Specifically, they suffer from the following deficiencies:

[0009] 1) Traditional dampers rely on manual adjustment, which has defects in opening control. For example, the threaded sleeve structure of patent CN221859176U has a slow response speed and cannot meet the needs of automation.

[0010] 2) As with the prior art of patent CN120368402A, there is no backup plan and the problem of airflow continuity when the main fan fails is not solved.

[0011] 3) The use of mechanical limiters, such as the DXZ-4 / 3 type, poses a risk of limit failure. Under vibration conditions, contact oxidation may occur, leading to malfunction. Utility Model Content

[0012] This utility model designs a damper mechanism for a fan with a standby limit switch for adjusting the opening stroke. By adding a pair of limit switches and limit contacts outside the actuator, it solves the problem of not being able to confirm whether the damper is fully open or closed due to the failure of the existing built-in limit switches in the actuator, and achieves precise, efficient and stable control of the damper stroke.

[0013] Therefore, this utility model provides a damper mechanism for a fan with an adjustable stroke and a spare limit switch, comprising an actuator, a damper shaft, a rotary arm, a first limit switch, a second limit switch, a first limit contact, a second limit contact, a handle, and a lever. The rotary arm and the handle are mounted on the damper shaft with their center lines perpendicular to the shaft's center line. The outer end of the handle is connected to the actuator, and the other end of the handle extends outward to connect to the lever. The first limit switch and the second limit switch are respectively installed at both ends of the lever's outer end's rotating arc trajectory. The first limit contact and the second limit contact are respectively protruding from the top of the first limit switch and the second limit contact.

[0014] The actuator is equipped with a limit unit. The limit unit is an SQ1 / SQ2 limit switch, which disconnects the control circuit after being triggered. The core components are limit switches, contactors, or H-bridge circuits.

[0015] A pointer is connected to the outer end of one side of the rotating arm, and an opening dial is set on the outside of the pointer.

[0016] Furthermore, to achieve the above objectives, this utility model is configured as follows:

[0017] In particular, the first limit switch and the second limit switch are fixed to the switch mounting plate. The top two wings of the switch mounting plate are trapezoidal and curved. After the first limit switch and the second limit switch are fixed to these two curved wings, the first limit contact 11 and the second limit contact are respectively located at the two ends of the arc-shaped trajectory of the lever's outer end.

[0018] In particular, two or more damper shafts are arranged adjacent to each other, and the outer ends of the rotating arms 4 installed on the adjacent damper shafts 3 are hingedly connected to each other.

[0019] In particular, the rotating arm and the handle are arranged in parallel. Furthermore, the rotating arm and the handle are fixedly installed at the lower and upper ends of the bushing, and the bushing is sleeved and fixed to the upper end of the damper shaft.

[0020] In particular, a sliding sleeve bearing is fitted onto the lower section of the damper shaft. Furthermore, a bearing is embedded in the inner wall of the upper end of the bearing.

[0021] In particular, the middle section of the lever bends upwards.

[0022] In particular, the first limit switch and the second limit switch are respectively fixedly connected to the first limit contact and the second limit contact at the top via elastic support rods on their outer sides.

[0023] In particular, the first and second limit switches are modified versions of the DXZ-4 / 3 type limit switches, with gold-plated contacts added to the first and second limit contacts to prevent oxidation.

[0024] Compared with the prior art, the beneficial effects of this utility model are:

[0025] This system integrates both electrical feedback and mechanical contacts for dual limit protection, controlling damper movement, providing stable opening control, and ensuring system reliability. It seamlessly switches in case of failure and requires no manual intervention throughout the entire process. It forms a closed-loop regulation system, supporting long-term fan operation and adjustment. It solves the problems of low adjustment accuracy, poor limit reliability, and lack of fault redundancy in existing damper mechanisms. It achieves highly reliable and stable control of the damper's opening and closing stroke, with a simple structure that is easy to promote. Attached Figure Description

[0026] The following figures are illustrative and should not be construed as limiting the scope of this invention. Referring to the figures helps the reader understand the embodiments of this invention and further appreciate its advantages and technical features.

[0027] Figure 1 This is a schematic diagram of the installation working structure for Example 1.

[0028] Figure 2 This is a partial structural diagram of Example 1.

[0029] Figure 3 This is a schematic diagram of the switch mounting plate structure in Example 1.

[0030] Figure 4 This is a schematic diagram of the corresponding structure of the limit switch and limit contact in Example 1.

[0031] The reference numerals in the figures include:

[0032] 1. Damper box; 2. Actuator; 3. Damper shaft; 4. Rotary arm; 5. Pull rod; 6. Pointer; 7. Opening degree dial; 8. Switch mounting plate; 9. First limit switch; 10. Second limit switch; 11. First limit contact; 12. Second limit contact; 13. Handle; 14. Shaft seat; 15. Shaft sleeve; 16. Lever. Detailed Implementation

[0033] It should be noted that:

[0034] In the description of this utility model, unless otherwise expressly specified and limited, the terms "comprising" and "having," and any variations thereof, are intended to cover other possible options under the same logic not listed. For example, a process, method, system, product, or device comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or device. The terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationships commonly used when the utility model product is in use. They are only for the convenience of describing the 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 the utility model. Furthermore, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. Furthermore, terms such as "horizontal," "vertical," and "suspended" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," not that the structure must be completely horizontal, but can be slightly tilted. The terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components.

[0035] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of any conflict, the definitions in this specification shall prevail.

[0036] Fan actuators are an indispensable and important component of automatic control systems. Their function is to receive control signals from the controller, change the magnitude of the controlled medium, and thus maintain the controlled variable at the required value or within a certain range. It is an assembly of actuator and control valve in an automatic control system, receiving signals from regulators or computers (DCS, PLC, etc.) and adjusting the flow rate of the process medium according to its location and characteristics in the process pipeline.

[0037] The typical working principle of a fan actuator is as follows: When the actuator receives a given control signal from the upstream stage, the signal is sent to a microcomputer or digital electronic control circuit via the input circuit. The control circuit drives a micro motor to rotate. After being reduced in speed by a reducer, the motor drives the controlled object (such as a damper) to rotate from 0 to 90 degrees via a coupling. Simultaneously, the rotation angle position signal is fed back to the control circuit. When the rotation angle reaches the given position or the mechanical endpoint, the motor stops rotating, eliminating the need for a limit switch. The actuator can also output a signal to display the rotation angle position or directly control another actuator.

[0038] The limiting unit includes a mechanical limiting device, an electronic limiting circuit, and a composite limiting structure, wherein:

[0039] Mechanical limit devices: These limit the displacement range of moving parts through physical contact, such as stops and pins, which are commonly found in equipment such as cranes and machine tools.

[0040] Electronic limit circuit: It uses limit switches or sensor trigger signals to control the start and stop of motors or actuators, such as the fire cut-off limit switch of electric hoists.

[0041] Composite limiting structure: such as the elastic limiting unit in BYD's patent, which achieves buffering and position locking functions through elastic elements.

[0042] Modern fan damper travel control system has the following technical features:

[0043] Dual control mode: Some products adopt pure pneumatic control or electrical dual control mode to ensure stable operation of the ventilation system.

[0044] Safety Interlock Mechanism: The full private server safety interlock design enhances the automation and safety of the damper, effectively preventing the spread of dangerous factors.

[0045] Adaptive adjustment: The mine pneumatic louver regulating damper optimizes the ventilation system by reserving an adjustable air window to solve the problem of air distribution.

[0046] In this invention, the damper integrates both closed-loop opening control and a two-stage stroke limit design, achieving dual mechanical and electrical limit control. It meets the requirements of GB / T 12238-2023 "Ventilation Regulating Butterfly Valves" and DL / T 5047-95 "Technical Specifications for Construction and Acceptance of Power Plants".

[0047] The principle of this utility model is that the adjustment accuracy is improved to ±1°, which is 80% higher than the ±5° adjustment accuracy of the traditional structure; the MTBF≥100,000 cycles limit reliability reaches 99.9%, which meets the GB / T 12238 standard; the damper mechanism is protected by setting the opening / closing limit positions to avoid actuator overload or mechanical collision.

[0048] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0049] Example 1: This utility model includes: an actuator 2, a damper shaft 3, a rotating arm 4, a first limit switch 9, a second limit switch 10, a first limit contact 11, a second limit contact 12, a handle 13, and a lever 16. (See attached diagram) Figure 1 , 2 As shown, the center line of the rotating arm 4 and the handle 13 is perpendicular to the center line of the damper shaft 3 and is mounted on the damper shaft 3. The outer end of the handle 13 is connected to the actuator 2. The other end of the handle 13 extends outward and is connected to the lever 16. The first limit switch 9 and the second limit switch 10 are respectively installed at both ends of the outer end of the lever 16 in the rotating arc trajectory. The top of the first limit switch 9 and the second limit switch 10 are respectively provided with the first limit contact 11 and the second limit contact 12.

[0050] As mentioned above, a pointer 6 is connected to the outer end of one side of the rotating arm 4, and an opening scale 7 is set outside the pointer 6.

[0051] As mentioned above, the first limit switch 9 and the second limit switch 10 are fixed on the switch mounting plate 8. (See attached diagram) Figure 3 As shown, the bottom edge of the switch mounting plate 8 is fixed to the outer wall of the damper box 1. The two wings at the top of the switch mounting plate 8 are trapezoidally bent so that after the first limit switch 9 and the second limit switch 10 are fixed on these two bent wings, the first limit contact 11 and the second limit contact 12 are respectively located on the two ends of the arc-shaped trajectory of the outer end of the lever 16. At the same time, it is also necessary to ensure that the rotating arm 4 rotates without interference inside the switch mounting plate 8.

[0052] In the aforementioned configuration, two or more damper shafts 3 are arranged adjacent to each other, and the outer ends of the rotating arms 4 mounted on the adjacent damper shafts 3 are hingedly connected to each other with a tie rod 5. In particular, a tie rod 5 is hinged to each of the two outer ends of the rotating arms 4.

[0053] As described above, the rotating arm 4 and the handle 13 are arranged in parallel. Furthermore, the rotating arm 4 and the handle 13 are fixedly installed at the lower and upper ends of the bushing 15, and the bushing 15 is sleeved and fixed to the upper end of the damper shaft 3.

[0054] As described above, a bearing seat 14 is slidably sleeved on the lower section of the damper shaft 3. Specifically, a bearing is embedded in the inner wall of the upper end of the bearing seat 14. The lower end of the bearing seat 14 is fixed to the outer wall of the damper box 1. The inner end of the damper shaft 3 passes through the outer wall of the damper box 1 and is connected to the damper blades. The air duct inside the damper box 1 is divided into several fan-shaped ventilation areas radially around its center. Damper blades, which can be driven to rotate by the damper shaft 3, are installed in these fan-shaped ventilation areas; these damper blades rotate synchronously, achieving a complete closure to full opening of the inner cavity of the damper box 1.

[0055] In particular, the middle section of lever 16 is bent upwards. This is to prevent interference with the top of the first limit switch 9 and the second limit switch 10 when the outer section of lever 16 rotates.

[0056] As mentioned above, the first limit switch 9 and the second limit switch 10 are respectively fixedly connected to the first limit contact 11 and the second limit contact 12 at the top via elastic support rods on their outer sides.

[0057] In this embodiment of the present invention, the opening degree dial 7 is disposed on the outer wall of the damper box 1.

[0058] In this embodiment of the invention, the average diameter of the circumscribed circle of the lever 16 is less than half the average diameter of the circumscribed circle of the handle 13. That is, the lever 16 is significantly thinner than the handle 13. In particular, the outer end of the lever 16 is slender and rigid to facilitate precise contact with the first limiting contact 11 or the second limiting contact 12.

[0059] In the embodiments of this utility model, as shown in the appendix Figure 2 As shown, on the damper box 1, the switch mounting plate 8, the first limit switch 9, the second limit switch 10, the first limit contact 11, the second limit contact 12, and the outer end of the lever 16 are located on the air inlet side, while the pointer 6 and the opening dial 7 are located on the air outlet side.

[0060] Preferably, the damper box 1 is 350mm long and has an outer diameter of 800mm-900mm, and the lever 16 is 210mm long. The switch mounting plate 8 is 67mm thick, and the top wing is 52mm wide with a trapezoidal bend of 135°.

[0061] Preferably, the first limit switch 9 and the second limit switch 10 are selected from OMRON WLCA12-2N-N.

[0062] In this embodiment of the invention, a limit unit is installed on the actuator 2. A limit unit is a device or component used to constrain the displacement or range of motion of an object, and is a core component in the field of mechanical safety control. Specifically, the limit unit installed on the actuator 2 is an SQ1 / SQ2 limit switch, which disconnects the control circuit upon triggering. The core components are limit switches, contactors, or H-bridge circuits. Among these, H-bridge circuits are particularly suitable for DC motor control, and the H-bridge circuit, in conjunction with the limit switch, achieves precise forward and reverse stopping.

[0063] In this embodiment of the utility model, under special circumstances, a manual operation mode is supported, that is, the connection between the actuator 2 and the handle 13 is unlocked, and the pointer 6 of the rotating arm 4 and the opening degree dial 7 are compared with the manual operation of the rotating handle 13 to control the opening angle of the damper blade.

[0064] Preferably, the first limit switch 9 and the second limit switch 10 are improved versions of the DXZ-4 / 3 type limit switch, and the first limit contact 11 and the second limit contact 12 are made of gold-plated contacts to prevent oxidation.

[0065] The implementation principle of this embodiment is as follows: During operation, the electrical limit mechanism installed on the actuator 2 works normally. While the driving arm 4 drives the pointer 6 to move in an arc on the opening dial 7 to indicate, the driving arm 4 drives the pull rod 5 and the damper shaft 3, so that all adjacent damper shafts 3 synchronously drive their respective damper blades to rotate and adjust the opening to control the ventilation volume. During this period, the pull rod 5 is responsible for mutual pulling so that all damper shafts 3 work synchronously.

[0066] When the electrical limit mechanism installed on the actuator 2 malfunctions, the outer end of the lever 16 performs mechanical limit monitoring based on the positional relationship between the first limit contact 11 and the second limit contact 12. When a possible abnormality occurs, the first limit contact 11 and the second limit contact 12 trigger an alarm signal, which is received by the first limit switch 9 and the second limit switch 10 and fed back to the actuator 2 for timely adjustment or cessation of operation.

[0067] The implementation principle of this embodiment is as follows: It has been clearly established both theoretically and experimentally that the working mode of the contact-limit switch, consisting of the first limit switch 9, the second limit switch 10, the first limit contact 11, and the second limit contact 12, has stable and accurate performance over a long period of time. However, after long-term operation, it is difficult to balance the sensitivity, accuracy, and sealing performance of the damper blade opening and closing. This is due to the influence of wind resistance pressure, as well as the polarization vibration of the damper shaft 3, the rotating arm 4, and the damper blade, and the mechanical inertial braking effect of rotational kinetic energy. This is also the reason why the damper equipment control, which relies solely on the electrical components of the actuator for limit control, is prone to inaccurate opening control stroke limit. In this embodiment, a redundant configuration is used for the damper opening control travel limit. Specifically, in addition to the existing electrical feedback of the limit unit in actuator 2, a pair of redundant limit components—a first limit contact 11 and a second limit contact 12—are added to the inner and outer edges of the damper shaft 3 and the rotating arm 4. These, along with the first limit switch 9 and the second limit switch 10, complete the damper blade system, establishing a dual limit protection system of electrical feedback and mechanical contacts. This achieves a balance between reliable, precise, and agile mechanism opening. Even in the event of damage to the actuator 2's own limit unit and electrical feedback failure, damper control can still be reliably completed using only the redundant contact-limit switch configuration.

[0068] Preferably, the control signals for actuator 2, first limit switch 9, and second limit switch 10 support both analog signals (0-10V, 4-20mA) and digital signals (Modbus, BACnet). In particular, the high-torque actuator 2 is suitable for driving large-sized or high-resistance damper blades. The locking time of actuator 2 is generally required to be completed within 1 to 3 seconds, balancing safety and system impact.

[0069] Example 2: After the implementation of this utility model, the limit switch of actuator 2 needs to be tested quarterly to verify its positioning accuracy within ±1mm and its operational reliability. Simultaneously, for the backup limit mechanisms of the first limit switch 9 and the second limit switch 10, a main system failure is simulated monthly to verify a switching response time of ≤1 second. This ensures that under emergency shut-off requirements, the limit switches and actuators support the damper response time, reducing the time from signal reception to full action to 1-3 seconds; the damper positioning accuracy and airflow adjustment accuracy are within ±5%; the damper sealing performance has a leakage rate of <5% in the fully closed state; and the operating temperature range is -20℃ to 80℃. The limit reliability reaches 99.9%, with an MTBF ≥ 100,000 cycles, conforming to GB / T 12238 standard.

[0070] Based on the embodiments of this utility model described above, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this utility model.

Claims

1. A damper mechanism for a fan with a standby limit switch for adjusting the opening stroke, comprising an actuator (2), a damper shaft (3), a rotating arm (4), a first limit switch (9), a second limit switch (10), a first limit contact (11), a second limit contact (12), a handle (13), and a lever (16); characterized in that, The centerline of the rotating arm (4) and the handle (13) is perpendicular to the centerline of the damper shaft (3) and is mounted on the damper shaft (3). The outer end of the handle (13) is connected to the actuator (2). The other end of the handle (13) extends outward to connect to the lever (16). The first limit switch (9) and the second limit switch (10) are respectively installed at both ends of the outer end of the lever (16) in the rotating arc trajectory. The top of the first limit switch (9) and the second limit switch (10) are respectively provided with a first limit contact (11) and a second limit contact (12).

2. The damper mechanism for a fan with an adjustable stroke reserve limit as described in claim 1, characterized in that, The actuator (2) is equipped with a limit unit; the limit unit is an SQ1 / SQ2 limit switch, which disconnects the control circuit after being triggered. The core components are limit switches, contactors or H-bridge circuits.

3. The damper mechanism for a fan with a standby limit switch for adjusting the opening stroke as described in claim 1, characterized in that, A pointer (6) is connected to the outer end of one side of the rotating arm (4), and an opening scale (7) is set on the outside of the pointer (6).

4. The damper mechanism for a fan with a standby limit switch for adjusting the opening stroke as described in claim 1, characterized in that, The first limit switch (9) and the second limit switch (10) are fixed on the switch mounting plate (8); the top two wings of the switch mounting plate (8) are trapezoidal and rolled up; the first limit switch (9) and the second limit switch (10) are respectively fixed on the two rolled up wings, and the first limit contact (11) and the second limit contact (12) are respectively located on the two ends of the outer arc trajectory of the lever (16).

5. The damper mechanism for a fan with a standby limit switch for adjusting the opening stroke as described in claim 1, characterized in that, Two or more damper shafts (3) are arranged adjacent to each other, and the outer ends of the rotating arms (4) installed on the adjacent damper shafts (3) are hinged to each other with a tie rod (5).

6. The damper mechanism for a fan with a standby limit switch for adjusting the opening stroke as described in claim 1, characterized in that, The rotating arm (4) and the handle (13) are arranged in parallel; the rotating arm (4) and the handle (13) are fixedly installed at the lower and upper ends of the bushing (15), and the bushing (15) is sleeved and fixed at the upper end of the damper shaft (3).

7. The damper mechanism for a fan with a standby limit switch for adjusting the opening stroke as described in claim 1, characterized in that, A sliding sleeve (14) is connected to the lower section of the damper shaft (3); a bearing is embedded in the inner wall of the upper end of the sleeve (14).

8. The damper mechanism for a fan with a standby limit switch for adjusting the opening stroke as described in claim 1, characterized in that, The middle section of lever (16) is bent upwards.

9. The damper mechanism for a fan with an adjustable stroke reserve limit as described in claim 1, characterized in that, The first limit switch (9) and the second limit switch (10) are respectively fixedly connected to the first limit contact (11) and the second limit contact (12) at the top via elastic support rods on their outer sides.

10. The damper mechanism for a fan with a standby limit switch for adjusting the opening stroke as described in claim 1, characterized in that, The first limit switch (9) and the second limit switch (10) are modified versions of the DXZ-4 / 3 type limit switch. The first limit contact (11) and the second limit contact (12) are made of gold-plated contacts to prevent oxidation.

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