Steel fireproof passive door

Abstract

The invention discloses a steel fireproof passive door, relates to the technical field of fireproof doors, and aims to solve the problem that door opening is affected due to large resistance of a door stopper during escape. According to the technical scheme, the fireproof door is characterized by comprising a door frame and two symmetrical door plates, and further comprising a fireproof structure used for forming the door plates and enabling the door plates to play a fireproof role; the door closer is arranged between the door frame and the door plate and is in a normally closed state, the door closer comprises a main shell, a hydraulic damping system and a main spring, the hydraulic damping system and the main spring are arranged in the main shell, a door closing damping main loop is formed in the hydraulic damping system, and a speed regulating valve and a buffer valve which can be independently adjusted are arranged on the door closing damping main loop; and an emergency disengagement mechanism. The emergency separation mechanism is arranged to automatically open the bypass oil duct when the emergency thrust exceeds the preset threshold value, door opening damping is greatly reduced, rapid evacuation of personnel is guaranteed, automatic reset is achieved after the event, balance of daily use and emergency escape can be guaranteed, and safety and durability are improved.

Description

Technical Field

[0001] This invention relates to the field of fire door technology, and more specifically, to steel fire-resistant passive doors. Background Technology

[0002] Passive doors are a type of door specifically designed for ultra-low energy buildings. Their main features are strong thermal insulation and high airtightness. These doors can effectively reduce heat exchange between indoors and outdoors, maintain a stable indoor temperature, and save energy consumption. Passive doors typically employ a multi-layered structural design, such as filling with thermal insulation materials and using high-performance sealing strips to ensure sound and heat insulation effects.

[0003] Regarding the opening and closing functions of doors, a built-in door closer is commonly used to achieve automatic closing of normally closed fire doors. Common door closers rely on springs to provide closing force, supplemented by a hydraulic damping system to control the closing speed, ensuring smooth closure and preventing violent impacts. However, the damping system of such conventional door closers is usually fixed or only has simple speed adjustment functionality. In emergencies, when people need to evacuate quickly and push the door outwards with great force, the strong damping force becomes a huge resistance, making it difficult to open the door and potentially obstructing escape routes, posing a serious safety hazard.

[0004] Therefore, a new solution is needed to address this problem. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a steel fireproof passive door, which has the advantages of automatically opening the bypass oil channel when the emergency thrust exceeds a preset threshold, greatly reducing the door opening damping and ensuring the rapid evacuation of personnel.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a steel fireproof passive door, comprising a door frame and two symmetrical door panels, and further comprising: The fireproof structure is used to form the door panel, so that the door panel can play a fireproof role. From the outside to the inside, it includes the first wood veneer panel, the first flame-retardant medium-density limiting plate, the heat insulation cotton, the first cold-rolled galvanized steel plate, the foam glass insulation board, the second cold-rolled galvanized steel plate, the second flame-retardant medium-density limiting plate, and the second wood veneer panel. A door closer is installed between the door frame and the door panel and is normally closed. The door closer includes a main housing, a hydraulic damping system and a main spring installed in the main housing. The hydraulic damping system forms a door closing damping main circuit. The door closing damping main circuit is equipped with an independently adjustable speed regulating valve and a buffer valve. The emergency release mechanism is set in parallel with the main circuit of the hydraulic damping system, including a valve body, a main valve core, a preload spring that provides preload force to the main valve core, and a bypass oil passage; The valve body contains a pressure sensing chamber and a bypass oil passage connected in parallel with the main closing damping circuit. The main valve core is slidably housed in the valve body, with its first end exposed to the pressure sensing chamber and its second end having a conical sealing surface for blocking or opening the bypass oil passage inlet. A preload spring is housed in the valve body and applies force to the main valve core, so that the conical sealing surface keeps blocking the bypass oil passage inlet under normal conditions. An adjustment structure is used to adjust the preload of the preload spring in order to set a preset pressure threshold for triggering the emergency release mechanism; The pressure sensing chamber is fluidly connected to the high-pressure chamber of the hydraulic damping system, so that when the door pushing force is applied to the door panel, the oil pressure in the high-pressure chamber can be transmitted to the pressure sensing chamber and act on the first end of the main valve core. When the thrust generated by the oil pressure on the main valve core is less than the preload of the preload spring, the bypass oil passage remains closed, and the hydraulic oil flows through the main closing damping circuit. When the thrust generated by the oil pressure on the main valve core is greater than the preload of the preload spring, the main valve core compresses the preload spring and generates displacement, thereby opening the inlet of the bypass oil passage, allowing the hydraulic oil to bypass through this passage and reducing the door opening damping.

[0007] The present invention is further configured such that: a buffer structure is provided between the door frame and the door panel, the buffer structure includes thermally broken aluminum profiles fixedly connected to the door frame and the door panel and a sealing strip provided between the two thermally broken aluminum profiles, the sealing strip being embedded in one of the thermally broken aluminum profiles and abutting against the other thermally broken aluminum profile.

[0008] The present invention is further configured such that the preset pressure threshold is set by the adjustment structure to correspond to the door opening thrust of 300 Newtons to 600 Newtons.

[0009] The invention is further configured to include a sealing structure disposed on both sides of an adjacent door panel to provide a sealing effect between the two door panels. The sealing structure includes a cover plate fixedly connected to one of the door panels and a sealing sheet fixedly connected to the cover plate. The sealing sheet has a cross-section of a "7" shape and, when folded, abuts against the other door panel.

[0010] The invention is further configured such that the sealing structure includes a fireproof strip disposed at the bottom of the door panel, the fireproof strip abutting against the door frame.

[0011] The invention is further configured such that the sealing sheet is made of fluororubber, and the wavy texture of the 7-shaped folded portion of its cross-section enhances the sealing contact with the other door panel.

[0012] The invention is further configured such that the fireproof strip is detachably installed at the bottom of the door panel, and the fireproof strip is made of expanded graphite material, which can expand at high temperature to form a sealing layer.

[0013] In summary, the present invention has the following beneficial effects: The door closer achieves smooth and controllable closing of the door panel through the coordinated action of the hydraulic damping system and the main spring. The speed regulating valve can independently adjust the main closing speed to adapt to the flow of people and safety requirements. The buffer valve intervenes at the end of the closing process to achieve a gentle and silent closing, effectively avoiding impact. The emergency escape mechanism automatically opens the bypass oil passage when the emergency thrust exceeds the preset threshold, greatly reducing the door opening damping and ensuring rapid evacuation of personnel. It also automatically resets afterward, ensuring a balance between daily use and emergency escape, and improving safety and durability. The fireproof structure adopts a multi-layer composite design, including, from the outside to the inside, a first wood veneer panel, a first flame-retardant medium-density limiting plate, heat insulation cotton, a first cold-rolled galvanized steel plate, and a foam glass insulation board. The materials of each layer complement each other. The first wood veneer panel provides flame retardancy and heat barrier, the heat insulation cotton and foam glass insulation board effectively block heat transfer, and the first cold-rolled galvanized steel plate enhances structural strength and impact resistance. The symmetrical arrangement ensures consistent fire performance on both sides, and together they form an efficient physical barrier to block flames and high temperatures, meeting high standard fire resistance requirements and improving the overall fireproof reliability of the door panel. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the structure of the present invention. Figure 2 ; Figure 3 Cross-sectional view of the present invention Figure 1 ; Figure 4 for Figure 3 Enlarged view of point A in the image; Figure 5 Cross-sectional view of the present invention Figure 2 ; Figure 6 This is a schematic diagram of the door closer in this invention; Figure 7 This is a cross-sectional view of the door closer in this invention; Figure 8 for Figure 7 Enlarged view of point B in the image.

[0015] In the diagram: 1. Door frame; 2. Door panel; 3. Main housing; 4. Hydraulic damping system; 5. Main spring; 6. Speed ​​control valve; 7. Buffer valve; 8. Valve body; 9. Main valve core; 10. Preload spring; 11. Bypass oil passage; 12. Thermally broken aluminum profile; 13. Sealing strip; 14. First wood veneer panel; 15. First flame-retardant medium-density limiting plate; 16. Thermal insulation cotton; 17. First cold-rolled galvanized steel sheet; 18. Foam glass insulation board; 19. Second cold-rolled galvanized steel sheet; 20. Second flame-retardant medium-density limiting plate; 21. Second wood veneer panel; 22. Sealing plate; 23. Sealing sheet; 24. Fireproof strip. Detailed Implementation

[0016] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0017] In the description of this invention, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limiting this invention.

[0018] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] Steel fireproof passive doors, such as Figures 1-8 As shown, it includes a door frame 1 and two symmetrical door panels 2, as well as a fireproof structure, a door closer, an emergency escape mechanism, an adjustment structure, and a sealing structure for constituting the door panels 2 and providing fire protection.

[0020] In one embodiment, the door closer is located in the hinge area between the door frame 1 and the door panel 2 and is always in a normally closed state. The main body of the door closer is a robust and sealed main housing 3, which houses the hydraulic damping system 4 that realizes the door closing function and the main spring 5 that provides the main force. When the door panel 2 is opened, the main spring 5 is compressed by a set of connecting rods as the door hinge rotates, thereby storing elastic potential energy. Once the external force for opening the door disappears, the elastic potential energy is immediately released and converted into the rotational torque that drives the door panel 2 to close. However, if only the main spring 5 were used for strong driving, the door panel 2 would directly impact the door frame 1. The hydraulic damping system 4 buffers this impact force. The hydraulic damping system 4 is filled with hydraulic oil, forming a closed oil circuit. When the main spring 5 pushes the door panel 2 to close, it simultaneously drives an oil pump linked to the door hinge, forcing the hydraulic oil to flow throughout the entire closing damping main circuit. When the hydraulic oil flows through the specially designed narrow throttling orifice in the closing damping main circuit, it generates huge fluid resistance. This resistance smoothly offsets part of the energy of the main spring 5, thus transforming the violent impact into a controllable and uniform closing action. To achieve precise control of different stages of the closing process, two sets of valve groups that can be independently and precisely adjusted are also set up. One is the speed regulating valve 6, which is mainly responsible for controlling the uniform speed of the door panel 2 during most of the stroke. The other is the buffer valve 7, which intervenes specifically in the final stage of the closing stroke to achieve a gentle closure.

[0021] Specifically, although the speed regulating valve 6 and the buffer valve 7 in the hydraulic damping system 4 of the door closer are connected in parallel on the same main closing damping circuit, they achieve functional division and coordination through flow channel design, and are independently adjustable without interference. The speed regulating valve 6 is usually an adjustable needle valve, and the size of its internal throttle orifice can be changed by rotating the adjusting screw. When the throttle orifice opening is increased, the resistance to the hydraulic oil flow decreases, and the overall closing speed increases; conversely, the closing speed becomes slower. This allows installers to adjust the main movement speed of the door panel 2 to the optimal state according to the specific requirements of the usage scenario, such as traffic flow and safety regulations.

[0022] The buffer valve 7 is an angle-sensing valve that typically activates when the door panel 2 is closed to the final 15 to 30 degrees. At this point, a cam or lever linked to the door hinge triggers the regulating mechanism of the buffer valve 7, causing the opening of its throttle orifice to automatically and gradually decrease. This results in a greater throttling effect on the hydraulic oil, generating stronger damping force. This is existing technology and will not be elaborated further. As the door panel 2 is about to fully close, its kinetic energy is rapidly and gently absorbed, significantly reducing its speed and ultimately achieving a silent, impact-free closing effect, effectively protecting the door frame 1, door panel 2, and the door closer itself. This design, with independent adjustment of the speed regulating valve 6 and the buffer valve 7, allows users to set a faster, standard closing speed to improve passage efficiency while ensuring sufficient buffering at the closing endpoint, perfectly balancing efficiency and safety, durability and user experience.

[0023] In one embodiment, the emergency disconnect mechanism is configured in parallel with the main circuit of the hydraulic damping system 4, including a valve body 8, a main valve core 9, a preload spring 10 that provides preload force to the main valve core 9, and a bypass oil passage 11. The valve body 8 has a pressure sensing chamber and a bypass oil passage 11 configured in parallel with the closing damping main circuit. The main valve core 9 is slidably housed in the valve body 8, with its first end exposed to the pressure sensing chamber to withstand the oil pressure from the hydraulic system. The second end has a conical sealing surface for blocking or opening the inlet of the bypass oil passage 11, ensuring that it can tightly block the inlet of the bypass oil passage 11 under normal conditions. The preload spring 10 is housed in the valve body 8 and applies force to the main valve core 9. This force is transmitted to the conical sealing surface, pressing it firmly against the inlet sealing seat, thereby completely isolating the bypass oil passage 11 under normal conditions, forcing all hydraulic oil to flow through the closing damping main circuit with damping function.

[0024] The pressure sensing chamber is fluidly connected to the high-pressure chamber formed by the hydraulic damping system 4 during the door opening action through a small pressure guide channel. This allows any thrust applied to the door panel 2 attempting to open it to be converted into oil pressure within the high-pressure chamber and instantaneously transmitted to the end face of the first end of the main valve core 9, generating a hydraulic thrust to move it. In normal, low-force door opening operations, this hydraulic thrust is insufficient to overcome the preload set by the preload spring 10, the bypass oil passage 11 remains closed, and the door closer operates in its normal damping state. However, in an emergency, when personnel forcefully push the door to escape, the applied thrust increases dramatically, causing the oil pressure in the high-pressure chamber to surge instantaneously. The preset pressure threshold is set by an adjustment structure to correspond to an outer door opening thrust of 300 to 600 Newtons. This range is higher than the normal door opening force (approximately 100-150N), effectively preventing false triggering, and is also lower than the force that might cause injury to personnel or be impossible to exert in a panic, ensuring the reliability of emergency escape.

[0025] Once the thrust generated by the hydraulic pressure on the main valve core 9 exceeds the preset threshold of the preload spring 10, the force balance is broken. The main valve core 9 immediately compresses the preload spring 10 and moves axially inward. The conical sealing surface at its second end then disengages from the sealing seat, thereby opening the inlet of the bypass oil passage 11. At this moment, the hydraulic oil obtains a flow path with minimal resistance, allowing a large amount to flow back directly from this bypass oil passage 11. This causes the resistance of the hydraulic damping system 4 to decrease dramatically in an instant, and the thrust required to open the door is suddenly reduced. The door panel 2 can be easily and quickly pushed open, greatly ensuring the smooth and safe evacuation of personnel in emergency situations. Afterward, when the door-pushing force is released and the pressure in the high-pressure chamber drops, the preload spring 10 will push the main valve core 9 back to its original position, re-closing the bypass oil passage 11. The entire system automatically returns to its normal damping and closing function without any manual reset.

[0026] In one embodiment, the adjustment structure is used to adjust the preload of the preload spring 10 to set a preset pressure threshold for triggering the emergency release mechanism. The pressure sensing chamber is fluidly connected to the high-pressure chamber of the hydraulic damping system 4, so that when the door pushing force is applied to the door panel 2, the oil pressure in the high-pressure chamber can be transmitted to the pressure sensing chamber and act on the first end of the main valve core 9. When the thrust generated by the oil pressure on the main valve core 9 is less than the preload of the preload spring 10, the bypass oil passage 11 remains closed, and the hydraulic oil flows through the door closing damping main circuit. When the thrust generated by the oil pressure on the main valve core 9 is greater than the preload of the preload spring 10, the main valve core 9 compresses the preload spring 10 and generates displacement, thereby opening the inlet of the bypass oil passage 11, allowing the hydraulic oil to bypass through this passage and reducing the door opening damping.

[0027] The core function of the adjustment structure is to accurately set and change the initial preload force of the preload spring 10 acting on the main valve core 9, thereby ultimately determining the preset pressure threshold for triggering the emergency disengagement function. This adjustment structure typically consists of an axially movable adjustment plug, a mating threaded pair, and a spring seat for transmitting force and preventing spring buckling. By rotating the adjustment plug with a special tool, it can be screwed in or out of the threaded hole in the valve body 8. When the adjustment plug is screwed in, it further compresses the preload spring 10 through the spring seat, thereby increasing its preload force on the main valve core 9; conversely, it reduces the preload force, changing the initial sealing pressure of the conical sealing surface of the main valve core 9 pressing against the inlet of the bypass oil passage 11. Technicians can perform precise calibration and adjustment on-site according to the specific door weight, usage frequency, and safety regulations, ensuring that the fire evacuation passage can maintain the necessary closing damping during daily use and can be easily pushed open by personnel in an emergency.

[0028] In one embodiment, such as Figures 1-5As shown, the fireproof structure is used to form the door panel 2, enabling the door panel 2 to play a fireproof role. The fireproof structure includes, from the outside to the inside, a first wood veneer panel 14, a first flame-retardant medium-density limiting plate 15, heat insulation cotton 16, a first cold-rolled galvanized steel plate 17, a foam glass insulation board 18, a second cold-rolled galvanized steel plate 19, a second flame-retardant medium-density limiting plate 20, and a second wood veneer panel 21. During installation, the main steps are as follows: First, the first wood veneer panel 14 and the first flame-retardant medium-density limiting plate 15 are pressed together with a high-temperature resistant adhesive to form an outer decorative layer. At the same time, the second wood veneer panel 21 and the second flame-retardant medium-density limiting plate 20 are pressed together to form an inner decorative layer. Then, heat insulation cotton 16 is covered on one side of the first cold-rolled galvanized steel plate 17, and the other side is bonded to the foam glass insulation board 18 with a high-temperature resistant adhesive. The other side of the foam glass insulation board 18 is then bonded to the second cold-rolled galvanized steel plate 19 to form a core fireproof and heat-insulating core layer. Finally, the outer veneer layer, the core fireproof and heat-insulating core layer, and the inner veneer layer are aligned as a whole, and then bonded together with a high-temperature resistant adhesive under mechanical pressure to obtain a complete door panel 2.

[0029] The fireproof structure begins with the outermost layer, the first wood veneer panel 14. This layer primarily meets the aesthetic needs of daily use, but it is also treated with flame retardants. When exposed to fire, it effectively inhibits its own combustion and forms a carbonized layer, delaying the direct attack of flames on the internal core structure. The next layer is the first flame-retardant medium-density limiting board 15. This layer is hard and not only provides a flat and stable base for the veneer panel, but more importantly, it constructs an effective thermal barrier in the early stages of a fire through its stable form at high temperatures and excellent thermal insulation performance, preventing flames from rapidly penetrating inward. Following this is the thermal insulation cotton 16, whose main components are high-temperature resistant rock wool or aluminum silicate wool. It has an extremely low thermal conductivity and a large number of static air pores, which can absorb and block the transfer of heat in the form of conduction and convection, significantly slowing down the speed at which heat flows through the door panel 2, thereby strongly supporting the overall thermal insulation performance of the door panel 2. Next is the first cold-rolled galvanized steel sheet 17, which provides basic structural strength and impact resistance. In a fire, the first cold-rolled galvanized steel sheet 17 is non-combustible and can effectively reflect some radiant heat. Its high melting point ensures that the structure remains intact at high temperatures. The next layer is a foam glass insulation board 18. This material is composed of countless closed glass bubbles. It is an inorganic, non-combustible material with low thermal conductivity. Under sustained high temperatures, it can maintain dimensional stability and physical strength for a long time without melting, dripping, or producing toxic fumes. It can ensure that the door panel 2 meets the insulation requirements for several hours in the standard fire resistance test.

[0030] Following this, the structure is symmetrically arranged inwards with the second cold-rolled galvanized steel sheet 19, the second flame-retardant medium-density limiting plate 20, and the second wood veneer panel 21, ensuring the consistency of performance and structural balance of the door panel 2 when both sides are exposed to fire. This multi-layered, heterogeneous composite structure cleverly integrates the decorative, flame-retardant, heat-insulating, and structural properties of the materials. The layers support each other and complement each other's functions, jointly constructing a reliable physical barrier that can effectively block flames and high temperatures and meet high standard fire resistance requirements.

[0031] In one embodiment, a sealing structure is disposed on both adjacent sides of the door panels 2 to provide a sealing effect between the two door panels 2. The sealing structure includes a cover plate 22 fixedly connected to one of the door panels 2 and a sealing sheet 23 fixedly connected to the cover plate 22. The cover plate 22 mechanically covers the gap generated when the two door panels 2 are joined, preventing flames from penetrating directly through the gap. The sealing sheet 23 has a V-shaped cross-section and abuts against the other door panel 2 after being folded. The sealing structure also includes a fireproof strip 24 disposed at the bottom of the door panel 2, which abuts against the door frame 1. The sealing sheet 23 is made of fluororubber, and its V-shaped folded portion has a wavy texture to enhance the sealing contact with the other door panel 2. Fluororubber is known for its excellent high-temperature resistance, excellent anti-aging ability, and elasticity over a wide temperature range, ensuring that it can maintain effective sealing performance for a long time even in high-temperature fire environments. The cross-section of the sealing strip 23 is designed in the shape of the number 7. This structure gives it a certain degree of elasticity and deformability. When installed, the sealing strip 23 is folded along the edge of the door so that one fold fits tightly against the cover plate 22, while the other fold uses the elastic recovery force of the material itself to continuously and forcefully press against the flat side of the adjacent door panel 2. This creates a flexible and continuous tight contact zone between the two door panels 2, achieving basic airtightness under normal conditions.

[0032] To further enhance the reliability and adaptability of the sealing sheet 23, the folded part of its seven-shaped cross-section is also designed with a wave-shaped texture, which increases the surface area and friction coefficient of the actual contact surface between the sealing sheet 23 and the opposite door panel 2. When the sealing sheet 23 is pressed against the other door panel 2 with a certain pressure, these wave-shaped textures can better fill and fit the unevenness that may exist on the other metal surface, thereby greatly enhancing the airtightness of the sealing sheet 23, making it difficult for smoke and flame to leak and penetrate between the two door panels 2.

[0033] In one embodiment, a buffer structure is provided between the door frame 1 and the door panel 2. The buffer structure includes a thermally broken aluminum profile 12 fixedly connected to the door frame 1 and the door panel 2, and a sealing strip 13 disposed between the two thermally broken aluminum profiles 12. The sealing strip 13 is embedded in one of the thermally broken aluminum profiles 12 and abuts against the other thermally broken aluminum profile 12. A fireproof strip 24 is detachably installed at the bottom of the door panel 2 through a slotted structure. The fireproof strip 24 is made of expanded graphite material and can expand at high temperature to form a sealing layer.

[0034] The fire-resistant strip 24 forms a tight abutment with the lower edge of the door frame 1 when the door is closed. This fire-resistant strip 24 is made of a special expanded graphite material and is installed in a detachable manner at the bottom of the door panel 2 for easy daily inspection and replacement. Under normal temperature conditions, it provides a basic seal. In the event of a fire, when the ambient temperature rises to its preset critical point, this fire-resistant strip 24 will rapidly expand in volume, thereby completely sealing the gap between the door panel 2 and the door frame 1, forming a dense and non-combustible expanded carbon layer. Working together with the fluororubber sealing sheet 23 on the vertical edge, it constructs a three-dimensional fireproof sealing network that is seamless, adaptive, and provides multiple layers of protection from room temperature to high temperature and from the vertical edge to the bottom.

[0035] Structural principle: The door frame 1 and the symmetrical door panels 2 are connected by a built-in normally closed door closer. The door closer is provided with closing force by the main spring 5 and achieves smooth closing by the hydraulic damping system 4. An emergency release mechanism is set in parallel on the door closer. By adjusting the preset pressure threshold of the structure, the main valve core 9 opens the bypass oil passage 11 under emergency thrust, which greatly reduces the door opening damping to ensure rapid evacuation. The interior of the door panel 2 adopts a multi-layer composite fireproof structure, which is composed of multiple layers of fireproof materials symmetrically stacked to form a highly efficient fireproof and heat insulation barrier. In terms of sealing structure, the door panels 2 are equipped with a combination of a wavy textured sealing sheet 23 and a cover plate 22. The bottom of the door is equipped with a detachable expanded graphite fireproof strip 24. Combined with the thermally broken aluminum profile 12 and sealing strip 13 between the door frame 1 and the door panel 2, a passive door that can be used in daily use or in emergency situations such as fire is formed.

[0036] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A steel fireproof passive door, comprising a door frame and two symmetrical door panels, characterized in that, Also includes: The fireproof structure is used to form the door panel, so that the door panel can play a fireproof role. From the outside to the inside, it includes the first wood veneer panel, the first flame-retardant medium-density limiting plate, the heat insulation cotton, the first cold-rolled galvanized steel plate, the foam glass insulation board, the second cold-rolled galvanized steel plate, the second flame-retardant medium-density limiting plate, and the second wood veneer panel. A door closer is installed between the door frame and the door panel and is normally closed. The door closer includes a main housing, a hydraulic damping system and a main spring installed in the main housing. The hydraulic damping system forms a door closing damping main circuit. The door closing damping main circuit is equipped with an independently adjustable speed regulating valve and a buffer valve. The emergency release mechanism is set in parallel with the main circuit of the hydraulic damping system, including a valve body, a main valve core, a preload spring that provides preload force to the main valve core, and a bypass oil passage. The valve body contains a pressure sensing chamber and a bypass oil passage connected in parallel with the main closing damping circuit. The main valve core is slidably housed in the valve body, with its first end exposed to the pressure sensing chamber and its second end having a conical sealing surface for blocking or opening the bypass oil passage inlet. A preload spring is housed in the valve body and applies force to the main valve core, so that the conical sealing surface keeps blocking the bypass oil passage inlet under normal conditions. An adjustment structure is used to adjust the preload of the preload spring in order to set a preset pressure threshold for triggering the emergency release mechanism; The pressure sensing chamber is fluidly connected to the high-pressure chamber of the hydraulic damping system, so that when the door pushing force is applied to the door panel, the oil pressure in the high-pressure chamber can be transmitted to the pressure sensing chamber and act on the first end of the main valve core. When the thrust generated by the oil pressure on the main valve core is less than the preload of the preload spring, the bypass oil passage remains closed, and the hydraulic oil flows through the main closing damping circuit. When the thrust generated by the oil pressure on the main valve core is greater than the preload of the preload spring, the main valve core compresses the preload spring and generates displacement, thereby opening the inlet of the bypass oil passage, allowing the hydraulic oil to bypass through this passage and reducing the door opening damping.

2. The steel fireproof passive door according to claim 1, characterized in that: A buffer structure is provided between the door frame and the door panel. The buffer structure includes thermally broken aluminum profiles fixedly connected to the door frame and the door panel, and a sealing strip disposed between the two thermally broken aluminum profiles. The sealing strip is embedded in one of the thermally broken aluminum profiles and abuts against the other thermally broken aluminum profile.

3. The steel fireproof passive door according to claim 1, characterized in that: The preset pressure threshold is set by the adjustment structure to correspond to the door opening thrust of 300 Newtons to 600 Newtons.

4. The steel fireproof passive door according to claim 1, characterized in that: It also includes a sealing structure, which is set on both sides of the door panel to provide a sealing effect between the two door panels. The sealing structure includes a cover plate fixedly connected to one of the door panels and a sealing sheet fixedly connected to the cover plate. The sealing sheet has a cross-section of a "7" shape and abuts against the other door panel after being folded.

5. The steel fireproof passive door according to claim 4, characterized in that: The sealing structure also includes a fireproof strip installed at the bottom of the door panel, which abuts against the door frame.

6. The steel fireproof passive door according to claim 4, characterized in that: The sealing strip is made of fluororubber, and its cross-section has a wavy texture in the 7-shaped folded portion to enhance the sealing contact with the other door panel.

7. The steel fireproof passive door according to claim 5, characterized in that: The fireproof strip is detachably installed at the bottom of the door panel. The fireproof strip is made of expanded graphite material, which can expand at high temperatures to form a sealing layer.

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