An electromagnetic device and a negative pressure fan

Abstract

This utility model discloses an electromagnetic device applied to a negative pressure fan to assist in the opening and closing of a ventilation butterfly valve. The electromagnetic device includes a support assembly, an electromagnetic assembly, a control assembly, and several adsorption components. The support assembly is installed between the ventilation butterfly valves, the electromagnetic assembly is installed on the support assembly, and the adsorption components are installed on the ventilation butterfly valves. The control assembly is connected to the electromagnetic assembly to control its energization and de-energization. When the negative pressure fan is working, the electromagnetic assembly maintains its original magnetic force and attracts the adsorption components, keeping the ventilation butterfly valve in the open position. When the negative pressure fan stops working, the control assembly activates the electromagnetic assembly, causing it to lose its magnetic force, thereby closing the ventilation butterfly valve under gravity. This completely solves the problem of traditional mechanical butterfly valves being unable to quickly and fully open after the fan starts, ensuring a stable airflow output.

Description

Technical Field

[0001] This utility model relates to the field of negative pressure fan technology, specifically to an electromagnetic device and a negative pressure fan. Background Technology

[0002] The ventilation butterfly valve in a negative pressure fan is mainly used to regulate air volume and pressure, and can be adjusted as needed for production. By adjusting the opening and closing degree of the butterfly plate, the flow rate of gas in the pipeline is controlled to stabilize production processes, reduce energy consumption, and ensure safe operation. Rotating the butterfly plate can also change the direction of gas flow, making the flow relatively stable, reducing resistance within the pipeline, and improving ventilation efficiency. During operation, it effectively prevents backflow of gas, avoiding accidents.

[0003] A prior art invention patent, CN119825729A, describes a negative pressure fan, characterized by comprising: an air collecting duct with a support frame on its inner wall, the support frame connecting to a motor, and the motor having several fan blades; the air collecting duct is a hollow cylindrical structure; an air guide shroud, with one end of the air collecting duct connected to the air guide shroud; and a ventilation butterfly valve, with the other end of the air collecting duct connected to the ventilation butterfly valve, the ventilation butterfly valve having a truncated cylindrical structure. This invention patent's negative pressure fan can operate normally in high-pressure areas, the ventilation butterfly valve exhibits low air resistance when open and good sealing performance when closed; the ventilation butterfly valve ensures stable airflow for the high negative pressure fan, enabling long-term stable operation of the equipment.

[0004] The applicant's research revealed that the patented technology only uses a traditional mechanical butterfly valve when the fan is turned on. After the fan is turned on, the butterfly valve cannot guarantee the opening angle. As the fan pressure increases, the air volume decreases, resulting in a reduction in thrust, which prevents the butterfly valve from opening completely. Utility Model Content

[0005] To overcome the technical defects mentioned above, such as the butterfly valve not being able to guarantee the opening angle after the fan is turned on, the air volume decreasing after the fan pressure increases, resulting in reduced thrust and the butterfly valve not being able to fully open, this utility model provides an electromagnetic device and a negative pressure fan.

[0006] To solve the above problems, this utility model is implemented according to the following technical solution:

[0007] The present invention discloses an electromagnetic device applied to a negative pressure fan to assist in the opening or closing of a ventilation butterfly valve. The electromagnetic device includes a support assembly, an electromagnetic assembly, a control assembly, and several adsorption components. The support assembly is installed between the ventilation butterfly valves, the electromagnetic assembly is installed on the support assembly, and the adsorption components are installed on the ventilation butterfly valves. The control assembly is connected to the electromagnetic assembly to control the energization and de-energization of the electromagnetic assembly. When the negative pressure fan is working, the electromagnetic assembly maintains its original magnetic force and attracts the adsorption components, keeping the ventilation butterfly valve in the open position. When the negative pressure fan stops working, the control assembly activates the electromagnetic assembly, causing it to lose its magnetic force, thereby closing the ventilation butterfly valve under the action of gravity.

[0008] Preferably, the electromagnetic component is provided with a groove, and the groove is provided with a magnetic element, a coil and a filling layer from the inside to the outside.

[0009] Preferably, the magnetic component is inverted T-shaped.

[0010] Preferably, a coil is sleeved on the magnetic component, and the coil is made of copper; the filler encapsulates the magnetic component and the coil.

[0011] Preferably, the filler is epoxy resin.

[0012] Preferably, the bottom of the groove is provided with an inwardly recessed blind hole for fixing the magnetic component.

[0013] Another aspect of this utility model describes a negative pressure fan, wherein the negative pressure fan includes the electromagnetic device described in any one of the first aspects.

[0014] Preferably, the negative pressure fan further includes a motor and fan blades; a plurality of adsorption components are provided on the leeward side of the ventilation butterfly valve; after the negative pressure fan is turned on, the adsorption components are adapted to the position of the electromagnetic component.

[0015] Preferably, the ventilation butterfly valve has a plurality of elastic components on its windward side; each elastic component is provided with a tension spring, one end of which is connected to the valve stem, and the elastic component is used to reset the ventilation butterfly valve.

[0016] Preferably, the negative pressure fan is further provided with a current transformer; the current transformer is used to sense the current of the motor, and the current transformer activates the control component to connect or disconnect the electromagnetic component.

[0017] Compared with the prior art, the beneficial effects of this utility model are:

[0018] This application utilizes the demagnetization principle of electromagnetic components. After the fan is turned on, the airflow blows the butterfly valve, and the electromagnetic components maintain their original magnetic force to attract the ventilation butterfly valve. This allows the valve to quickly open to its maximum state upon opening, completely solving the problem of traditional mechanical butterfly valves failing to open quickly and fully after the fan starts, ensuring stable airflow output. When the fan pressure rises, the electrical control system maintains the butterfly valve fully open, effectively eliminating insufficient opening caused by valve plate rebound or airflow impact, thus preventing airflow attenuation and thrust reduction. The electromagnetic components achieve instantaneous synchronous opening or closing of the butterfly valve, with a response speed far superior to traditional manual or passive mechanical structures, making it particularly suitable for negative pressure systems requiring frequent start-stop or variable operating conditions. The rigid connection between the support components and the inner wall of the air collection duct disperses the vibration load on the valve plate under airflow impact, reducing mechanical wear and extending service life; it also avoids the valve shaft misalignment or jamming problems caused by insufficient support in traditional butterfly valves. By eliminating unnecessary throttling losses (turbulent energy consumption when a traditional butterfly valve is partially open), this invention can reduce the fan load. The measured energy saving rate is about 15% to 20% higher than that of mechanical valves, and the long-term economic benefits are significant. Attached Figure Description

[0019] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings, wherein:

[0020] Figure 1 This is a structural schematic diagram of the negative pressure fan of this utility model;

[0021] Figure 2 This is a schematic diagram of the negative pressure fan of this utility model from another perspective;

[0022] Figure 3 yes Figure 2 Sectional view of AA;

[0023] Figure 4 This is a schematic diagram illustrating the structural principle of an electromagnetic device and a ventilation butterfly valve according to this utility model.

[0024] Figure 5 This is a schematic diagram of the leeward side of an electromagnetic device according to this utility model;

[0025] Figure 6 This is a schematic diagram of the windward side of an electromagnetic device according to this utility model;

[0026] Figure 7 This is a schematic diagram of the structure of an electromagnetic component in an electromagnetic device according to this utility model;

[0027] Figure 8 yes Figure 7 Sectional view of BB;

[0028] In the diagram: 1 - Negative pressure fan, 11 - Electromagnetic device, 111 - Base, 112 - Valve stem, 113 - Left butterfly plate, 114 - Right butterfly plate, 115 - Support assembly, 116 - Electromagnetic assembly, 1161 - Groove, 1162 - Magnetic component, 1163 - Coil, 1164 - Filling layer, 1165 - Mounting blind hole, 117 - Elastic component, 1171 - Tension spring, 118 - Adsorption component, 12 - Motor, 121 - Bracket, 13 - Fan blade, 14 - Air collector, 141 - First protective net, 142 - Second protective net. Detailed Implementation

[0029] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0030] like Figures 1 to 8 As shown, the electromagnetic device 11 of this utility model is applied to a negative pressure fan 1 to assist in the opening or closing of a ventilation butterfly valve. The electromagnetic device 11 includes a support assembly 115, an electromagnetic component 116, a control assembly, and several adsorption components 118. The support assembly 115 is installed between the ventilation butterfly valves, the electromagnetic component 116 is installed on the support assembly 115, and the adsorption components are installed on the ventilation butterfly valves. The control assembly is connected to the electromagnetic component 116 to control the energization and de-energization of the electromagnetic component 116. When the negative pressure fan 1 is working, the electromagnetic component 116 maintains its original magnetic force and attracts the adsorption components 118, keeping the ventilation butterfly valve in the open position. When the negative pressure fan 1 stops working, the control assembly switches on the electromagnetic component 116, causing it to lose its magnetic force, thereby causing the ventilation butterfly valve to close under the action of gravity.

[0031] Understandably, such as Figures 3-4As shown, the support component 115 connects the air collection duct 14 in the negative pressure fan 1 to the valve stem 112 on the ventilation butterfly valve, providing stable support for the ventilation butterfly valve and the air collection duct 14. An external control component enables the linkage control between the electromagnetic component 116 and the negative pressure fan 1. In this embodiment, the control component is an external circuit control box. The control box detects the current in one phase of the motor 12 of the negative pressure fan 1 and outputs a control signal based on the current transformer detected within the control box. Simultaneously, the ventilation butterfly valve of the negative pressure fan 1 opens due to the fan's airflow, and the electromagnet at the valve attracts the butterfly plate, maintaining the magnetic attraction. When the fan stops, the current control signal detected by the current transformer in the control box disappears. This triggers the timer module within the control box, controlling its output to energize and demagnetize the electromagnet. The damper releases and returns to the closed position due to the spring force of the butterfly plate. When the negative pressure fan 1 starts running, the electromagnetic component 116 maintains its magnetic force. When the negative pressure fan 1 stops working, the control component connects to the electromagnetic component 116, causing the ventilation butterfly valve to return to its closed, sealed state under its own gravity. Compared to a continuously energized electromagnetic holding device, this reduces energy consumption by more than 80%. The response time of the electromagnetic component 116 from power failure to complete demagnetization is extremely short, ensuring that the ventilation butterfly valve closes immediately when the fan stops, preventing secondary dust generation caused by backflow of air from the pipeline. The support component 115 can be directly spliced ​​and installed on the existing ventilation butterfly valve without modifying the valve body structure. The control component has a built-in capacitor as a backup power source, which can maintain the electromagnetic force for ≥30 seconds in the event of a sudden power failure, ensuring that the butterfly valve still has a buffer time when the negative pressure fan 1 stops abnormally. The adsorption component 118 adopts a split layout. In this embodiment, the adsorption component 118 is installed on the left and right butterfly plates 114 in the ventilation butterfly valve, and its position is adapted to the electromagnetic component 116.

[0032] In a preferred embodiment, the electromagnetic component 116 is provided with a groove 1161, and the groove 1161 is provided with a magnetic element 1162, a coil 1163, and a filling layer 1164 from the inside to the outside. The magnetic element 1162 is inverted T-shaped. The coil 1163, made of copper, is sleeved on the magnetic element 1162; the filling layer 1164 surrounds the magnetic element 1162 and the coil 1163. The filling layer 1164 is made of epoxy resin. The bottom of the groove 1161 is provided with an inwardly recessed mounting blind hole 1165 for fixing the magnetic element 1162.

[0033] The inverted T-shaped magnetic component and the blind mounting hole 1165 at the bottom of the groove 1161 form a fitting structure, significantly enhancing vibration resistance and preventing displacement or loosening under high-frequency operating conditions. After curing, the epoxy resin filling layer forms an integrated support, reducing mechanical stress concentration between the coil and the magnetic component. In this embodiment, the coil 1163 is made of copper, which has high conductivity and reduces resistance loss. Combined with the inverted T-shaped magnetic component 1162, it effectively increases magnetic flux density. The inverted T-shaped structure expands the contact area between the magnetic component 1162 and the coil 1163, shortening the heat conduction path by more than 40%. Blind hole positioning enables rapid installation of the electromagnetic assembly 116, improving production efficiency. The epoxy resin filling layer 1164 encapsulates the coil 1163. In this embodiment, using epoxy resin as the filling layer 1164 can suppress wear on the coil 1163 during use. The inverted T-shaped magnetic component 1162 and the filler form a double safety net: the inverted T-shaped magnetic component 1162 provides mechanical pull-out resistance, and the filler has high shear strength, which can withstand the impact acceleration when the ventilation butterfly valve is brought close without causing magnetic core displacement. Furthermore, the epoxy filler layer 1164 achieves an IP67 sealing rating, making it suitable for direct use in high-humidity coastal environments.

[0034] The second embodiment of this utility model provides a negative pressure fan 1, which includes an electromagnetic device 11. The negative pressure fan 1 also includes a motor 12 and fan blades 13. A plurality of adsorption components 118 are provided on the leeward side of the ventilation butterfly valve. When the negative pressure fan 1 is turned on, the adsorption components 118 are positioned to match the electromagnetic component 116. A plurality of elastic components 117 are provided on the windward side of the ventilation butterfly valve. A tension spring 1171 is provided on each elastic component 117, one end of which is connected to the valve stem 112. The elastic component 117 is used to reset the ventilation butterfly valve. A current transformer is also provided on the negative pressure fan 1. The current transformer is used to sense the current of the motor 12, and the current transformer activates the control component to connect or disconnect the electromagnetic component 116.

[0035] Understandably, the negative pressure fan 1 includes an air collection duct 14 and a ventilation butterfly valve. The inner wall of the air collection duct 14 is equipped with a bracket 121 for fixing and connecting a motor 12. The motor 12 has several fan blades 13. The air collection duct 14 has a hollow cylindrical structure. The fan blades 13 are mounted close to the motor 12. Gas flowing through the air collection duct 14 can cool the operating motor 12, extending its service life. The splicing installation method facilitates installation and maintenance. The ventilation butterfly valve includes a left butterfly plate 113 and a right butterfly plate 114. One side of the valve stem 112 is hinged to the left butterfly plate 113, and the other side is hinged to the right butterfly plate 114, enabling the ventilation butterfly valve to open and close. In this embodiment, the ventilation butterfly valve is radially inclined to the air collection duct 14, allowing the valve to close quickly when the negative pressure fan 1 stops working. Even if the tension spring fails unexpectedly, gravity alone can ensure the valve is fully closed. The two ends of the valve stem 112 are fixedly connected to the base 111 by bolts, which makes disassembly and assembly convenient and improves production efficiency.

[0036] The adsorption component 118 on the leeward side of the ventilation butterfly valve aligns with the electromagnetic component 116, establishing a rated magnetic force upon startup of the negative pressure fan 1. In this embodiment, the current transformer is housed within the control box, monitoring the motor current in real time. Upon power failure of the fan, the control component is triggered to connect the electromagnetic component, causing the ventilation butterfly valve to close completely under gravity, preventing reverse airflow contamination after the negative pressure in the pipe network disappears. During negative pressure fan operation, the electromagnetic component maintains its adsorption through a permanent magnet, saving energy compared to traditional electric actuators. The current transformer is located within the external control box of the negative pressure fan, while the electromagnetic component 116 is directly mounted on the ventilation butterfly valve. The current transformer detects abnormal current in the motor 12, such as short circuits or overloads, with millisecond-level response. When the motor 12 is running under no-load or low-load conditions, the current transformer automatically disconnects the electromagnetic component based on a current threshold. The current transformer and control box are options readily available in this field.

[0037] After the motor 12 of the negative pressure fan 1 is turned off, the electromagnetic force disappears, and the left butterfly plate 113 and right butterfly plate 114 close under the combined action of gravity torque and the additional force of the elastic component 117 and the tension spring 1171. The preload of the tension spring 1171 can cover the viscous resistance of the grease, ensuring a 100% valve closure rate. The elastic component 117 adopts a composite structure of 304 stainless steel sheet and tension spring 1171, which can still ensure valve closure even in the event of an electromagnetic failure. The tension spring 1171 and the valve stem 112 adopt a quick-release pin structure for rapid maintenance. The second embodiment reduces the starting current of the negative pressure fan 1 by 15% at the same power, ensuring reliable closure, and is suitable for ventilation systems in livestock sheds, tunnels, and clean rooms with strict requirements for energy consumption, noise, and leakage rate.

[0038] In this embodiment, as Figures 1-2As shown, a first protective net 141, made of stainless steel, is installed on the air inlet of the air collecting duct 14. The first protective net 141 has good corrosion resistance, heat resistance, low-temperature strength, and mechanical properties; it has good hot workability such as stamping and bending, and does not exhibit heat treatment hardening. In one embodiment, stainless steel is used to make the first protective net 141. It serves a safety protection function, preventing external objects, impurities, or animals from entering the fan, avoiding damage to the fan blades 13, motor 12, or other components, and protecting the safe operation of the fan. A second protective net 142 is connected to the air outlet of the air collecting duct 14. The second protective net 142 has a regularly arranged mesh structure. Stainless steel has good corrosion resistance, heat resistance, low-temperature strength, and mechanical properties; it has good hot workability such as stamping and bending, and does not exhibit heat treatment hardening. In one embodiment, stainless steel is used to make both the first and second protective nets 141, making them less susceptible to deformation due to external forces. The second protective mesh 142, made of stainless steel, features a regularly arranged grid structure and is installed at the air outlet of the air collection duct 14. It provides double-layer safety protection for the internal structure of the negative pressure fan, making the structure more stable and extending the fan's service life. The working principle of the electromagnetic device described in this utility model is as follows:

[0039] When the negative pressure fan 1 starts, the airflow blows the left butterfly plate 113 and the right butterfly plate 114 open. The control component synchronously outputs pulses to the inverted T-shaped magnetic component 1162 and the copper coil 1163 to form a central magnetic flux in the groove 1161. The magnetic flux then passes through the air gap and instantly attracts the left and right suction components 118 on the leeward side of the left and right butterfly plates 113 and 114. The magnetic pull of the suction component 118 overcomes the preload of the tension spring 1171, causing the left and right butterfly plates 114 to synchronously flip outward to the fully open position.

[0040] The continuous operation of the negative pressure fan 1 is controlled by the control component to switch to energy-saving mode, which reduces the average power consumption of the electromagnetic component 116 and ensures that the magnetic properties do not decay.

[0041] When the negative pressure fan 1 stops or the external power is cut off, the current transformer senses that the motor current has dropped to an extremely low value. When the control component connects the electromagnetic component 116, the inverted T-shaped magnetic component 1162 demagnetizes and the attraction force disappears. The left butterfly plate 113 and the right butterfly plate 114 close under the combined action of gravity torque and the restoring force of the tension spring 1171, sealing with zero leakage.

[0042] After closing, the elastic component 117 presses the valve plate tightly onto the sealing ring. This closed-loop control uses the fan start / stop as the sole trigger source, requiring no additional sensors. It is both energy-efficient and reliable, and suitable for harsh environments such as -20℃ to 60℃, high humidity, and high dust.

[0043] Other structures of the electromagnetic device and negative pressure fan described in this embodiment are referred to in the prior art.

[0044] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the technical solution of the present utility model shall still fall within the scope of the technical solution of the present utility model.

Claims

1. An electromagnetic device applied to a negative pressure fan to assist the opening or closing of a ventilation butterfly valve, characterized in that, The electromagnetic device includes a support assembly, an electromagnetic assembly, a control assembly, and several adsorption components; The support assembly is installed between the ventilation butterfly valves, the electromagnetic assembly is installed on the support assembly, and the adsorption element is installed on the ventilation butterfly valve; the control assembly is connected to the electromagnetic assembly to control the electromagnetic assembly to be energized and de-energized. When the negative pressure fan is working, the electromagnetic component maintains its original magnetic force and attracts the adsorption element, keeping the ventilation butterfly valve in the open position; When the negative pressure fan stops working, the control component activates the electromagnetic component, causing it to lose its magnetic force, thereby causing the ventilation butterfly valve to close under the action of gravity.

2. The electromagnetic device according to claim 1, characterized in that: The electromagnetic component is provided with a groove, and the groove is provided with a magnetic element, a coil and a filling layer from the inside to the outside.

3. An electromagnetic device according to claim 2, characterized in that: The magnetic component is inverted T-shaped.

4. An electromagnetic device according to claim 3, characterized in that: A coil is fitted onto the magnetic component, and the coil is made of copper. The filling layer encloses the magnetic element and the coil.

5. An electromagnetic device according to claim 4, characterized in that: The filler layer is made of epoxy resin.

6. An electromagnetic device according to claim 2, characterized in that: The bottom of the groove is provided with an inwardly recessed blind hole for fixing magnetic components.

7. A negative pressure fan characterized by, The negative pressure fan includes the electromagnetic device described in any one of claims 1 to 6.

8. A negative pressure fan according to claim 7, characterized in that: The negative pressure fan also includes a motor and fan blades; Several adsorption components are provided on the leeward side of the ventilation butterfly valve. When the negative pressure fan is turned on, the position of the adsorption component and the electromagnetic component are adapted.

9. A negative pressure fan according to claim 7, characterized in that: Several elastic components are provided on the windward side of the ventilation butterfly valve. The elastic component is provided with a tension spring, one end of which is connected to the valve stem. The elastic component is used to reset the ventilation butterfly valve.

10. A negative pressure fan according to claim 8, characterized in that: The negative pressure fan is also equipped with a current transformer; The current transformer is used to sense the current of the motor, and the current transformer activates the control component to connect or disconnect the electromagnetic component.

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